JP7592238B2 - Flush water tank device and flush toilet equipped with same - Google Patents

Description

The present invention relates to a flush water tank device and a flush toilet equipped with the same, and in particular to a flush water tank device that supplies flush water to the toilet body of a flush toilet, and a flush toilet equipped with the same.

2. Description of the Related Art Conventionally, flush water tank devices that supply flush water to the toilet body of a flush toilet are known, for example, from the devices described in Patent Documents 1 to 3.
First, in the conventional flush water tank devices described in Patent Documents 1 and 2, a small tank is provided within the water storage tank main body, and the water storage area in which flush water is stored within the water storage tank main body is divided into two water storage areas, one inside and one outside the small tank.
In addition, an opening for switching between large and small flushes is provided in the side wall of the small tank, and a switching valve for switching between large and small flushes is provided in this opening so as to be able to open and close.
As a result, when a large flush of the toilet is performed, the switch valve for switching between large and small flushes opens, and the flush water stored in the two water storage areas inside and outside the small tank is used for the large flush of the toilet. On the other hand, when a small flush of the toilet is performed, the switch valve for switching between large and small flushes closes, and only the flush water stored in one of the two water storage areas (outside the small tank) is used for the small flush of the toilet.
In the conventional flush water tank devices described in Patent Documents 1 and 2, the changeover valve for switching between large and small flushes is kept closed by the difference in the amount of flush water inside and outside the small tank acting on the changeover valve in a closing direction, and when the difference in the amount of flush water inside and outside the small tank disappears, the changeover valve opens.
Next, in the conventional flush water tank device described in Patent Document 3, a drain valve for a large flush and a drain valve for a small flush are each provided so as to be able to open and close relative to the drain outlet at the bottom of the water storage tank. These drain valves open and close the drain outlet by rotating vertically about a rotating shaft, and also function as a large/small flush switching valve that allows switching between large and small flushes.
In addition, a brake plate is provided on the opposite side of the valve body of such a drain valve (a switching valve for switching between large and small flushes) with respect to the pivot shaft. As a result, when the valve body of the drain valve descends due to gravity to close, water pressure acts as resistance on the upper surface of the brake plate, suppressing the descent of the valve body and delaying the closing operation of the valve body.

JP 2015-151758 A (Patent No. 6361856 A) JP 2015-31000 A Japanese Patent Application Publication No. 8-232319

However, the large/small flush switching valve in the conventional flush water tank apparatus described in the above-mentioned Patent Documents 1 and 2 opens in a direction against the water pressure relative to the opening, and the drain valve in the conventional flush water tank apparatus described in the above-mentioned Patent Document 3 also opens in a direction against the water pressure relative to the drain outlet. For this reason, when the toilet is in the large flush mode, depending on the water pressure acting on the valve body, there is a risk that the valve body will not be able to open sufficiently and will enter a closed state, creating the problem that the large/small flush switching valve cannot be reliably maintained in an open state.
Therefore, when the large flush mode of the toilet is being executed, there is a problem that the flush water that should be used for the large flush in the water tank body may not be supplied to the toilet body in sufficient quantity, which may result in poor cleaning of the toilet.
Therefore, in recent years, a pressing issue has been how to accurately execute each of the toilet's large and small flush modes by reliably maintaining the large/small flush switching valve in an open state when the toilet is in the large flush mode, and by reliably maintaining the large/small flush switching valve in a closed state when the toilet is in the small flush mode.

The present invention has been made to solve the problems of the prior art and the problems that have been required in recent years, and aims to provide a flush water tank device that can reliably maintain the large/small flush switching valve in an open state when the toilet is in a large flush mode, and can reliably maintain the large/small flush switching valve in a closed state when the toilet is in a small flush mode, and can accurately execute both the large and small flush modes of the toilet, and a flush toilet equipped with the same.

In order to solve the above-mentioned problems, the present invention provides a flush water tank device that supplies flush water to the toilet body of a flush toilet, comprising a water storage tank body that is capable of storing flush water for flushing the toilet body, a large/small flush switching device that makes it possible to set the amount of flush water supplied from the water storage tank body to the toilet body to either large or small, and an operation device that operates the large/small flush switching device when starting a toilet flush, thereby making it possible to switch the flush mode of the toilet to either a large flush mode or a small flush mode. The large/small flush switching device has a switching opening formed to pass through the partition wall and enabling communication between the first and second water storage sections of the water storage tank body, and a switching opening that is open to the switching opening and that is formed to pass through the partition wall and enables communication between the first and second water storage sections of the water storage tank body, and a switching opening that is open to the switching opening. and a large/small flush switching valve that is arranged to be closable, the partition wall being provided with a switching valve support portion that rotatably supports the large/small flush switching valve at or near the switching opening, and the large/small flush switching valve being provided with a rotating shaft portion that is rotatably supported by the switching valve support portion, a valve body portion that is provided on the rotating shaft portion and enables the switching opening to be opened and closed, and a valve body auxiliary portion that is provided on the opposing side or parallel side to the valve body body portion, with the rotating shaft portion as the center, and at least one of the valve body body portion and the valve body auxiliary portion is provided with a valve body adjustment portion that adjusts the valve body body portion to maintain an open state when the operating portion is switched to the large flush mode, and the valve body body portion and the non-valve body portion are configured to maintain a closed state due to a water volume difference or water pressure difference of the flush water stored in each of the first water storage portion and the second water storage portion of the water storage tank body, when the operating portion is switched to the small flush mode.
In the present invention configured in this manner, when starting to flush the toilet, for example, when the operating unit is switched to large flush mode, the valve body main body of the large/small flush switching valve in the large/small flush switching device opens, and the switching opening in the partition wall that separates the first water storage section and the second water storage section of the water tank main body is opened.
At this time, the valve body adjustment section provided on at least one of the valve body main body and valve body auxiliary section of the large/small flush switching valve can adjust the center of gravity position of the entire large/small flush switching valve so that the valve body main body in the large flush mode is maintained in an open state.
This makes it possible to prevent the valve body portion of the large/small flush switching valve from accidentally going into a closed state while the large flush mode of the toilet is being executed.
Therefore, when the large flush mode of the toilet is being executed, it is possible to prevent a shortage of flush water supplied from the water storage tank body to the toilet body, which would result in a decrease in toilet flushing performance during large flushes.
On the other hand, when starting to flush the toilet, for example, when the operating unit is switched to the small flush mode, the valve body main body and valve body auxiliary part of the large/small flush switching valve are maintained in a closed state due to the difference in water volume or water pressure of the flush water stored in each of the first and second water storage units of the water tank body.
Therefore, it is possible to avoid the risk that the valve body main body of the large/small flush switching valve will accidentally open while the toilet's small flush mode is being executed, causing the flush water stored in the second water storage section of the water tank body to be discharged from the switching opening into the first water storage section, making it impossible to accurately execute the toilet's small flush mode.
As a result, when the toilet is in large flush mode, the large/small flush switching valve can be reliably maintained in an open state, and when the toilet is in small flush mode, the large/small flush switching valve can be reliably maintained in a closed state, so that each of the toilet's large and small flush modes can be accurately executed.

In the present invention, preferably, the switching valve support portion is provided near the upper portion of the switching opening, and the valve body main portion is provided so that, when the valve is open, its lower end portion can rotate from near the bottom surface of the switching opening toward an upward position around the pivot shaft portion.
In the present invention configured in this manner, there is a demand for the entire water storage tank body to be made smaller in view of the recent diversification of designs for flush water tank devices and flush toilets, and in the second water storage section in the water storage tank body, which does not have a drain outlet, it is desirable to use the stored flush water in a way that reduces residual water as much as possible.
Furthermore, if the switching valve support part is provided at the bottom of the switching opening, when the valve body main body is open and the flushing water in the second water storage part of the water tank body is discharged from the switching opening, there is a higher risk that something that will hinder the discharge of the flushing water, such as the rotating shaft part of the large/small flush switching valve or part of the valve body main body, will remain near the bottom of the switching opening.
This can result in residual water remaining in the second water storage section of the water storage tank body, resulting in a problem of reduced drainage efficiency at the switching opening.
In contrast, in the present invention, a switching valve support part that rotatably supports the pivot shaft part of the large/small flush switching valve is provided near the upper part of the switching opening, and the valve body main body part of the large/small flush switching valve is provided so that when the valve is open, its lower end part is rotatable from near the bottom surface of the switching opening toward an upward position around the pivot shaft part, so that no space is required near the bottom surface of the switching opening for the pivot shaft part of the large/small flush switching valve.
Therefore, when the valve body main body is open and the cleaning water in the second water storage section of the water storage tank main body is discharged through the switching opening, there is no longer anything near the bottom of the switching opening to hinder the discharge of the cleaning water, thereby reducing the amount of residual water in the second water storage section of the water storage tank main body.
Furthermore, when the valve body main body of the large/small flush switching valve is open, when its lower end rotates from near the bottom of the switching opening toward an upward position around the pivot shaft, even if gravity or water pressure acts on the valve body main body to rotate it in the closing direction, the valve body adjustment portion can be adjusted to maintain the valve body main body in the open state.
Therefore, when the toilet is in the large flush mode, it is possible to prevent the valve body of the large/small flush switching valve from accidentally entering a closed state, thereby preventing an insufficient amount of flush water being supplied from the water storage tank body to the toilet body, which in turn prevents a decrease in toilet flushing performance during large flushes.

In the present invention, the valve body adjustment portion of the large/small flush switching valve is preferably provided on the side opposing the valve body main portion with the rotation shaft portion as the center, and includes a weight member provided on the valve body auxiliary portion.
In the present invention configured in this manner, a weight member is provided in the valve body auxiliary portion of the large/small flush switching valve as a valve body adjustment portion, so that the center of gravity position of the entire large/small flush switching valve can be adjusted so that the valve body main portion in the large flush mode is maintained in the open state.
Therefore, when the operating unit is switched to the large flush mode, the weight of the weight member of the valve body adjustment unit causes both the valve body main body and the valve body auxiliary part of the large/small flush switching valve to rotate in the opening direction around the pivot shaft part, and the valve body main body can be adjusted to maintain the open state.
Therefore, while the large flush mode of the toilet is being performed, the valve body portion of the large/small flush switching valve can be prevented from being erroneously placed in a closed state, thereby ensuring that the large flush of the toilet is performed.

In the present invention, preferably, the weight member is plate-shaped, and the valve body auxiliary portion has a weight mounting portion to which the weight member is detachably attached, the weight mounting portion having a weight mounting surface provided on the tip side of the valve body auxiliary portion, and a retaining portion provided on this weight mounting surface and holding the weight member from the side so that the weight member can slide in the longitudinal direction of the valve body auxiliary portion, the retaining portion having a hook portion provided on the tip side of the weight mounting surface and capable of elastically deforming in an out-of-plane direction relative to the weight mounting surface when the weight member is attached or detached, and a concave curved surface is formed on the surface of the hook portion opposite to the weight mounting surface so as to partially reduce the thickness between the base end and tip end of the hook portion.
In the present invention configured in this manner, in the weight mounting portion of the valve body auxiliary portion, a holding portion that holds the plate-shaped weight member from the side so that it can slide in the longitudinal direction of the valve body auxiliary portion is provided on the tip side of the weight mounting surface and is equipped with a hook portion that can elastically deform in the out-of-plane direction relative to the weight mounting surface when the weight member is attached or detached, and a concave curved surface is formed on the surface of the hook portion opposite the weight mounting surface so as to partially reduce the thickness between the base end and tip end of the hook portion, thereby dispersing stress generated at the base end of the hook portion when the weight member is attached or detached.
This avoids stress concentration at the base end of the hook portion, thereby preventing damage to the hook portion due to stress concentration, and allows the weight member to be securely attached and held in place against the weight mounting portion of the valve body auxiliary part.
Therefore, since the weight member can be reliably provided in the valve body auxiliary portion of the large/small flush switching valve as a valve body adjustment portion, the center of gravity position of the entire large/small flush switching valve can be adjusted so that the valve body main body portion in the large flush mode is maintained in the open state.
Therefore, when the operating unit is switched to the large flush mode, the weight of the weight member of the valve body adjustment unit causes both the valve body main body and the valve body auxiliary part of the large/small flush switching valve to rotate in the opening direction around the pivot shaft part, and the valve body main body can be adjusted to maintain the open state.
As a result, the valve body of the large/small flush switching valve can be prevented from being mistakenly placed in a closed state while the large flush mode of the toilet is being performed, thereby ensuring that the large flush of the toilet is performed.

In the present invention, preferably, in a plan view, the base end of the hook portion is connected to the weight mounting surface adjacent to the base end of the hook portion by curved surfaces of at least two radii of curvature, the curved surfaces including a first curved surface of a first radius of curvature formed on the base end side of the hook portion and a second curved surface of a second radius of curvature formed on the weight mounting surface side adjacent to the base end of the hook portion from the first curved surface, and the first radius of curvature is set larger than the second radius of curvature.
In the present invention configured in this manner, the base end of the hook portion is connected, in a planar view, to the weight mounting surface adjacent to the base end of the hook portion by at least two first curved surfaces having a first radius of curvature and a second curved surface having a second radius of curvature, and the curved surfaces are set so that the first radius of curvature of the first curved surface formed on the base end side of the hook portion is larger than the second radius of curvature of the second curved surface formed on the weight mounting surface side adjacent to the base end of the hook portion.Therefore, when the weight member is attached or detached, or when the weight member is attached to the weight mounting portion of the valve body auxiliary portion, stress generated at the base end of the hook portion can be dispersed.
This avoids stress concentration at the base end of the hook portion, thereby preventing damage to the hook portion due to stress concentration, and allows the weight member to be securely attached and held in place against the weight mounting portion of the valve body auxiliary part.
Therefore, since the weight member can be reliably provided in the valve body auxiliary portion of the large/small flush switching valve as a valve body adjustment portion, the center of gravity position of the entire large/small flush switching valve can be adjusted so that the valve body main body portion in the large flush mode is maintained in the open state.
Therefore, when the operating unit is switched to the large flush mode, the weight of the weight member of the valve body adjustment unit causes both the valve body main body and the valve body auxiliary part of the large/small flush switching valve to rotate in the opening direction around the pivot shaft part, and the valve body main body can be adjusted to maintain the open state.
As a result, the valve body of the large/small flush switching valve can be prevented from being mistakenly placed in a closed state while the large flush mode of the toilet is being performed, thereby ensuring that the large flush of the toilet is performed.

In the present invention, preferably, the pivot shaft portion of the large/small flush switching valve is arranged to extend horizontally within the second water storage section of the water storage tank body, and is arranged on the first water storage section side of the water storage tank body relative to the switching opening when viewed from the central axis direction of the switching opening, and the valve body main body portion has a protrusion portion arranged to protrude in a direction perpendicular to the axial direction of the pivot shaft portion, and a tip portion arranged in a direction perpendicular to the protruding direction of the protrusion portion, and the center of gravity of the valve body main body portion is positioned so that an orientation extending horizontally from the protrusion portion toward the tip portion is maintained in the open valve state.
In the present invention configured in this manner, the rotating shaft portion of the large/small flush switching valve can be arranged to extend horizontally within the second water storage section of the water storage tank body, and can be arranged on the first water storage section side of the water storage tank body rather than the switching opening when viewed from the central axis direction of the switching opening.
Furthermore, in the valve body main body, a protrusion is provided so as to protrude in a direction perpendicular to the axial direction of the pivot shaft, and a tip portion is provided in a direction perpendicular to the protruding direction of this protrusion, so that the center of gravity of the valve body main body in the open valve state can be positioned so that an attitude extending horizontally from the protrusion portion to the tip portion is maintained.
This makes it possible to adjust the position of the center of gravity of the entire large/small flush switching valve so that the valve body portion in the large flush mode is maintained in the open state.
Therefore, while the large flush mode of the toilet is being performed, the valve body portion of the large/small flush switching valve can be prevented from being erroneously placed in a closed state, thereby ensuring that the large flush of the toilet is performed.

In the present invention, preferably, the large/small flush switching device further includes a swinging member that is swingably connected to the valve body auxiliary part of the large/small flush switching valve, and a chain-like or linear connecting member that connects this swinging member to the operating part and can be pulled up by the operating part, and when the connecting member is pulled up by the operating part when the small flush mode of the toilet is started, the swinging member is pulled up together with the connecting member from an initial position in which the valve body main body part is in an open state, and is capable of swinging while connected to the valve body auxiliary part in the direction in which the valve body main body part closes, and then, when the connecting member is released from its pulled up state, the swinging member is configured to be released from its connection with the valve body auxiliary part and to be swingable to the initial position while the closed state of the valve body main body part is maintained.
In the present invention thus configured, when the small-flush mode of the toilet is started and the chain-like or linear connecting member is operated to be pulled up by the operating unit, the oscillating member is pulled up together with the connecting member from the initial position in which the valve body main body is in the open state, and oscillates while connected to the valve body auxiliary part in the direction in which the valve body main body is closed, so that the valve body main body is in the closed state. After that, when the connecting member is released from the pulled-up state, the oscillating member is released from the connection with the valve body auxiliary part, and can oscillate to the initial position with the valve body main body maintained in the closed state.
In other words, when the chain-like or linear connecting member is released from the pulled-up state and pulled down, only the oscillating member which has been released from its connection with the valve body auxiliary part can oscillate to the initial position independently of the valve body main part and the valve body auxiliary part.
Furthermore, if the center of gravity of the entire large/small flush switching valve is adjusted so that the valve body main body in the large flush mode is maintained in an open state in order to make the water tank body smaller and save water, there is a risk that, for example, when the water level difference between the first and second water storage sections of the water tank body becomes small while the toilet is in the small flush mode, the downward movement of the chain or linear connecting member will cause the valve body main body in the closed state to open.
Therefore, in the present invention, by connecting a chain-like or linear connecting member only to a oscillating member that can oscillate independently of the valve body main body and the valve body auxiliary part, it is possible to prevent the downward movement of the chain-like or linear connecting member from interfering with the valve body main body and the valve body auxiliary part, which are maintained in a closed valve state, even when the water level difference between the first and second water storage parts of the water storage tank body is small while the toilet is in the small-flush mode.
This avoids the risk of the downward movement of the chain-like or linear connecting member causing the valve body main body, which is in a closed state, to open when the toilet's small-flush mode is in operation, and allows the valve body main body to be maintained in a closed state.
Therefore, when the toilet's small-flush mode is being executed, it is possible to suppress malfunctions in which the valve body main body or valve body auxiliary part, which has been maintained in a closed state, erroneously rotates in the opening direction, causing the valve body main body, which is in a closed state, to switch to an open state, thereby enabling the toilet's small-flush mode to be executed accurately.

Next, the present invention is a flush toilet equipped with the above-mentioned flush water tank device.
In the present invention configured in this manner, when the toilet is in large flush mode, the large/small flush switching valve can be reliably maintained in an open state, and when the toilet is in small flush mode, the large/small flush switching valve can be reliably maintained in a closed state.
It is therefore possible to provide a flush toilet equipped with a flush water tank apparatus that can accurately execute both the large and small flush modes of the toilet.

The flush water tank device of the present invention, and the flush toilet equipped with it, can reliably maintain the large/small flush switching valve in an open state when the toilet is in large flush mode, and can reliably maintain the large/small flush switching valve in a closed state when the toilet is in small flush mode, allowing each of the toilet's large and small flush modes to be accurately performed.

1 is a plan view showing a flush toilet equipped with a flush water tank apparatus according to an embodiment of the present invention. FIG. 2 is a side view of a flush water tank apparatus according to one embodiment of the present invention, and is a cross-sectional view taken along line II-II of the flush toilet shown in FIG. 1. 1 is a block diagram showing the basic configuration of a flush water tank apparatus according to an embodiment of the present invention. 1 is a schematic front cross-sectional view of a water storage tank body and a small tank, illustrating the basic configuration of a flush water tank apparatus according to an embodiment of the present invention. 2 is a plan view showing the internal structure of the water storage tank body of a flush water tank apparatus according to an embodiment of the present invention; FIG. This is a partially enlarged front cross-sectional view of the jet nozzle accommodating portion in the water storage tank body of a flush water tank device according to one embodiment of the present invention, showing the state in which the flow path switching valve is set in the flow path on the suction port side of the throat pipe. This is a partially enlarged front cross-sectional view of the jet nozzle accommodating portion in the water storage tank body of a cleaning water tank device according to one embodiment of the present invention, showing the state in which the flow path switching valve is set in the flow path on the water storage tank body side other than the suction port side of the throat pipe. 2 is a partial front cross-sectional view showing an enlarged view of the water storage tank body and small tank of a flush water tank apparatus according to one embodiment of the present invention. FIG. 1 is a perspective view of a small tank of a flush water tank apparatus according to an embodiment of the present invention, viewed diagonally from above and to the front right. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 9 is a partially enlarged perspective view showing an enlarged portion of the large/small flush switching valve device of the flush water tank apparatus according to one embodiment of the present invention shown in FIG. 8 . FIG. 1 is a partially enlarged view of the large/small flush switching valve device in a flush water tank apparatus according to one embodiment of the present invention, showing the open state of the switching valve body of the large/small flush switching valve device in a standby state before the start of the toilet flush operation and when the large flush operation of the toilet has begun. FIG. 2 is a partially enlarged view of the large/small flush switching valve device in a flush water tank apparatus according to one embodiment of the present invention, showing the closed state of the switching valve body of the large/small flush switching valve device when the small flush operation of the toilet has begun. 1 is a partially enlarged view of the large/small flush switching valve device in a flush water tank apparatus according to one embodiment of the present invention, showing the closed state of the switching valve body of the large/small flush switching valve device during a small flush of the toilet. FIG. This is a partially enlarged view of the large/small flush switching valve device in a flush water tank device according to one embodiment of the present invention, showing the state in which the switching valve body of the large/small flush switching valve device, which is in a closed state, opens while water is being supplied from the water supply valve device to the water storage tank body after the small flush of the toilet has been completed. 1 is an enlarged plan view showing a weight mounting portion of a valve body auxiliary portion of a switching valve body in a large/small flush switching valve device for a flush water tank apparatus according to an embodiment of the present invention. FIG. 13 is a cross-sectional view taken along line XIIIA-XIIIA in FIG. 12. A cross-sectional view similar to Figure 13A showing the weight mounting portion of the valve body auxiliary part of the switching valve body in a large/small flush switching valve device of a flush water tank apparatus according to one embodiment of the present invention, showing the state when the weight member is attached to or detached from the weight mounting portion. 4 is a flowchart showing the flow of operation of a flush water tank apparatus according to one embodiment of the present invention.

A flush toilet equipped with a flush water tank apparatus according to one embodiment of the present invention will now be described with reference to the accompanying drawings.
First, the basic structure of a flush toilet equipped with a flush water tank apparatus according to one embodiment of the present invention will be described with reference to Figures 1 and 2.
FIG. 1 is a plan view showing a flush toilet equipped with a flush water tank apparatus according to one embodiment of the present invention, and FIG. 2 is a side view of the flush water tank apparatus according to one embodiment of the present invention, and is a cross-sectional view taken along line II-II of the flush toilet shown in FIG.

1 and 2, a flush toilet 2 equipped with a flush water tank apparatus 1 according to one embodiment of the present invention comprises a toilet body 4. The flush water tank apparatus 1 of this embodiment, the details of which will be described later, is disposed on the upper surface of the rear side of this toilet body 4.
Next, as shown in Figures 1 and 2, the toilet body 4 comprises a bowl portion 6 provided on its front side, a rim portion 8 formed on the upper edge of the bowl portion 6, and a shelf portion 10 formed on the inner circumference of the rim portion 8.
Furthermore, an inlet 12a of a trap drainage channel 12 opens at the bottom of the bowl portion 6 of the toilet body 4, and this trap drainage channel 12 is equipped with an ascending pipe 12b extending upward and a descending pipe 12c extending downward. As can be seen from the shape of this trap drainage channel 12, the flush toilet 2 according to this embodiment is a wash-down type toilet that discharges waste by a drop in height.
In this embodiment, a form applied to a wash-down toilet will be described, however, the present invention is not limited to this form and can also be applied to other types of flush toilets, such as a so-called siphon type toilet, which uses the siphon action to suck up waste in the bowl and discharge it to the outside all at once through the drain trap pipe.

Next, the toilet body 4 is equipped with a water conduit 16 into which flushing water discharged from the drain outlet 14 of the flushing water tank device 1 flows, a first rim spout 18 formed in the center of the left side when viewed from the front of the shelf portion 10, and a second rim spout 20 formed in the rear right side when viewed from the front.
In addition, the water conduit 16 branches downstream into a first water conduit 16a and a second water conduit 16b, and the flushing water in the water conduit 16 reaches the first rim outlet 18 via the first water conduit 16a, while reaching the second rim outlet 20 via the second water conduit 16b. The flushing water is discharged from the first rim outlet 18 and the second rim outlet 20, respectively, to wash the bowl portion 6 and discharge waste matter from the trap drain 12.

Next, the flush water tank assembly 1 of this embodiment will be described in detail with reference to Figures 1 to 11D.
First, Fig. 3 is a block diagram showing the basic configuration of a flush water tank apparatus according to one embodiment of the present invention. Also, Fig. 4 is a schematic front cross-sectional view of the storage tank main body and small tank showing the basic configuration of a flush water tank apparatus according to one embodiment of the present invention. Furthermore, Fig. 5 is a plan view showing the internal structure of the storage tank main body of a flush water tank apparatus according to one embodiment of the present invention.
In addition, in the flush water tank device 1 shown in Figure 3, for convenience, the entire internal structure of the water storage tank main body 22 has been diagrammatically simplified, and therefore the structural arrangement of the flush water tank device 1 shown in Figures 4 and 5 is different.
Also, in the flush water tank apparatus 1 shown in FIG. 4, some of the structure has been simplified.
Furthermore, with regard to the left-right direction of the flush water tank device 1 shown in Figures 1 to 11D, the left side in the left-right direction when viewed from the front side (user side) of the toilet body 4 of the flush toilet 2 is defined as the "left side," and the right side in the left-right direction when viewed from the front side of the toilet body 4 is defined as the "right side."

First, as shown in Figures 3 to 5, the flush water tank device 1 comprises a ceramic outer tank T, a water storage tank body 22 which is an inner tank housed within this outer tank T, and a water supply pipe 24 connected to a water source such as a water line (not shown).
In the water storage tank body 22 , a portion of the flush water supplied via a water supply pipe 24 is stored so that it can be supplied to the water passage 16 of the toilet body 4 .
As shown in FIG. 4, the water storage tank body 22 is disposed at a relatively low position on the rear side of the toilet body 4, and the upper end of the water storage tank body 22 is positioned at a low height, that is, it is a so-called low silhouette type tank, and as shown in FIG. 5, it is formed in a flat shape that is long in the left-right direction when viewed in a plane.

Next, as shown in FIGS. 3 to 5, a water supply valve device 28 is provided inside the water storage tank body 22 for stopping the supply of flush water supplied from the water supply pipe 24 via the constant flow valve 26.
The water supply valve device 28 includes a main valve 30 which is a water supply valve that opens and closes the water supply passage downstream of the constant flow valve 26 .
The flush water tank apparatus 1 also includes an operating device 32 (operating lever 32a, drive rotation shaft 32b) which is an operating section for operating the water supply valve apparatus 28 when starting a toilet flush.

Next, the internal structure and operating mechanism of the water supply valve device 28 will be described in detail with reference to FIGS.
First, the water supply valve device 28 further includes a poppet valve 34 , a float 36 , and a float-side pilot valve 38 .
The poppet valve 34 is an operating side pilot valve that opens and closes the main valve 30 by rotating the operating lever 32a and the drive rotary shaft 32b of the operating device 32. The float 36 moves up and down by buoyancy according to the water level in the water storage tank body 22. The float side pilot valve 38 opens and closes the main valve 30 by the up and down movement of the float 36.

Next, the main structure of the main valve 30 portion of the water supply valve device 28 includes a main valve body 30a, which is a pilot-type diaphragm valve, a main valve seat 30b on which the main valve body 30a sits, and a pressure chamber 30c which causes the main valve body 30a to move relative to the main valve seat 30b due to internal pressure.
As a result, the water supply valve device 28 can be switched between either a water stopping state in which the main valve body 30a is seated on the main valve seat 30b to stop the water flow, or a water supply state in which the main valve body 30a is separated from the main valve seat 30b to supply water.
The pressure chamber 30c is provided with a poppet hole 34a and a float-side pilot hole 38a for releasing the pressure in the pressure chamber 30c.
Furthermore, a poppet valve 34 is provided in a poppet hole 34a of the pressure chamber 30c so as to be able to open and close. This poppet valve 34 is connected to a drive rotation shaft 32b that connects the operating lever 32a and the water supply valve device 28. This drive rotation shaft 32b is rotatable about its axis in conjunction with manual operation of the operating lever 32a by the user, and forms part of an operating section for operating the water supply valve device 28.
Furthermore, a float side pilot valve 38 is provided in a float side pilot hole 38a of the pressure chamber 30c. This float side pilot valve 38 can be opened and closed by the up and down movement of the float 36 according to the water level of the flush water in the water storage tank body 22.
It is also possible to provide an electromagnetic valve instead of the poppet valve 34 and to change the operating device 32 to a switch or the like.

In addition, a bleed hole (not shown) is provided in the main valve body 30a, and when the water flow is stopped, the bleed hole (not shown) connects the primary side flow path A of the water supply pipe 24 to the inside of the pressure chamber 30c.
The poppet hole 34a is formed so that its opening area is larger than the opening area of the float-side pilot hole 38a. Also, the poppet hole 34a is formed at a higher position than the float-side pilot hole 38a, as shown in FIG.

Furthermore, as shown in FIG. 4, the water supply valve device 28 is normally in a water-stopped state, in which the poppet hole 34a and the float side pilot hole 38a are both closed, and the primary side flow path A of the water supply pipe 24 is connected to the pressure chamber 30c through a bleed hole (not shown).
As a result, the water pressure in the primary side flow path A of the water supply pipe 24 and the pressure chamber 30c is the same water pressure (primary side flow path pressure α), and the secondary side flow path B of the water supply pipe 24 is open to the atmosphere.Since the area on which the water pressure acts on the main valve body 30a is larger than the area of the primary side flow path A, the main valve body 30a is pressed against the main valve seat 30b and is in a closed state.

Next, in the water supply valve device 28, when the poppet hole 34a is opened by the poppet valve 34 and/or the float side pilot hole 38a is opened by the float side pilot valve 38, cleaning water flows out of the pressure chamber 30c and the pressure in the pressure chamber 30c decreases.
As a result, the main valve body 30a moves away from the main valve seat 30b to open the valve and enter a water discharge state.

In addition, in the water supply valve device 28, when the poppet hole 34a is closed by the poppet valve 34 and the float side pilot hole 38a is closed by the float side pilot valve 38, the pressure in the pressure chamber 30c again becomes the primary side flow path pressure α, the main valve body 30a moves toward the main valve seat 30b, and finally the valve is closed (water stop state).
At this time, the cleaning water in the primary side flow path A is injected little by little into the pressure chamber 30c through the bleed hole, so that the main valve body 30a is closed (water-stopped state) a predetermined time later after the poppet hole 34a and the float side pilot hole 38a are closed.
A jet pump unit 42 (details of which will be described later) is provided in the water supply passage downstream of the water supply valve device 28 and connected via a vacuum breaker valve 40 .

Next, the jet pump unit 42 will be described in detail with reference to FIGS. 3 to 6B.
First, as shown in Figures 3 to 5, the jet pump unit 42 is provided downstream of a water supply pipe 44 extending from the vacuum breaker valve 40, and includes, from the upstream side to the downstream side, a jet nozzle 46, a flow path switching valve 48, and a throat pipe 50.
In addition, each of these jet nozzles 46, flow path switching valve 48, and suction port 50a of the throat pipe 50 are arranged within a jet nozzle accommodating section H that protrudes downward from one of the left and right sides of the water storage tank body 22 (the right side when looking at the water storage tank body 22 from the front side in Figure 3).

6A and 6B show partially enlarged front cross-sectional views of a jet nozzle housing portion in the water storage tank body of a flush water tank apparatus according to one embodiment of the present invention.
FIG. 6A shows a state in which the flow passage switching valve 48 of the jet pump unit 42 is set in the flow passage on the suction port 50 a side of the throat pipe 50 .
On the other hand, FIG. 6B shows a state in which the flow path switching valve 48 of the jet pump unit 42 is set to the flow path on the water storage tank body 22 side other than the suction port 50 a side of the throat pipe 50 .
As shown in Figures 4 to 6B, the jet nozzle 46 of the jet pump unit 42 is positioned at least partially submerged inside the water storage tank body 22, and sprays cleaning water supplied from a water supply pipe 44 extending from the vacuum breaker valve 40.
The vacuum breaker valve 40 is provided to draw in air from the outside and prevent the inside of the water supply pipe 44 from the vacuum breaker valve 40 to the jet nozzle 46 from becoming negative pressure.

Next, as shown in Figures 3 to 6B, the flow path switching valve 48 of the jet pump unit 42 is provided near the downstream side of the jet nozzle 46, and is capable of switching the flow path of the cleaning water sprayed from the jet nozzle 46 depending on the water level in the water storage tank main body 22.
3 to 6B, the throat pipe 50 of the jet pump unit 42 is provided in the vicinity of the downstream side of the flow path switching valve 48. A suction port 50a is formed at one end (upstream end) of the throat pipe 50, while a discharge port 50b for discharging wash water is formed at the other end (downstream end) of the throat pipe 50.
Furthermore, as shown in FIG. 4, the throat pipe 50 has a pipe shape extending from its suction port 50a to its exhaust port 50b, for example, formed into an inverted U-shape (or, in other words, an inverted J-shape or a gooseneck shape).
Here, the jet nozzle 46 is disposed so as to face the suction port 50a of the throat pipe 50. The suction port 50a of the throat pipe 50 and the jet nozzle 46 are always submerged in the water storage tank body 22.

Also, as shown in Figures 3, 4, 6A and 6B, the flow path switching valve 48 is capable of switching the flow path of the jetted cleaning water to either a toilet flushing flow path 52 that communicates with the toilet body 4, or a tank water storage flow path 54 that communicates with the water storage tank body 22, depending on the water level in the water storage tank body 22.
Specifically, when flushing the bowl portion 6 of the toilet body 4, the suction port 50a of the throat pipe 50 is opened by the flow path switching valve 48, and the flush water jetted from the jet nozzle 46 flows into the suction port 50a of the throat pipe 50 through the toilet flushing flow path 52. The flush water that flows into the throat pipe 50 flows out of the discharge port 50b of the throat pipe 50 and is discharged from the drain port 14 of the flush water tank device 1 to the water conduit 16 side of the toilet body 4.
On the other hand, the tank water storage flow path 54 is a flow path in which, when water is stored in the water storage tank main body 22, the suction port 50a of the throat pipe 50 is closed by the flow path switching valve 48, and the cleaning water jetted from the jet nozzle 46 is directed into the water storage tank main body 22 outside the throat pipe 50 without flowing into the throat pipe 50.

Incidentally, when the flow path switching valve 48 is set to the toilet flushing flow path 52, the jet nozzle 46 jets flush water from the suction port 50a of the throat pipe 50 toward the inside, thereby inducing a so-called "jet pump effect" in which the flow rate of flush water flowing through the throat pipe 50 is increased beyond the flow rate of flush water jetted from the jet nozzle 46. As a result, flush water at an increased flow rate is supplied from the discharge port 50b of the throat pipe 50 through the drain port 14 toward the water conduit 16 of the toilet body 4.
In addition, the term "jet pump action" used in this specification means that the forceful flow of cleaning water sprayed from the jet nozzle 46 toward the suction port 50a of the throat pipe 50 creates a negative pressure that directly draws in the surrounding cleaning water, such as near the suction port 50a of the throat pipe 50, without relying on other mechanical elements such as a pump, and uses this negative pressure to transport the cleaning water in the water storage tank body 22 that has been sucked into the throat pipe 50 toward the toilet body 4.

4 and 5, an overflow pipe 56 extending in the vertical direction is provided inside the water storage tank body 22. This overflow pipe 56 is provided adjacent to the downcomer pipe portion 38b extending in the vertical direction of the throat pipe 50 of the jet pump unit 42, and its lower end is connected to the drain outlet 14.
As a result, when the water level in the water storage tank body 22 rises above the stop water level and exceeds the position of the overflow outlet 56a of the overflow pipe 56, the flushing water flows into the overflow pipe 56 and is supplied as make-up water to the water conduit 16 of the toilet body 4 from the drain outlet 14.
3 to 6B, a make-up water channel (make-up water pipe 58) that connects a portion of the tank storage flow path 54 to the overflow port 56a is provided inside the water storage tank body 22. As a result, a portion of the flush water in the tank storage flow path 54 shown in Fig. 6B flows into the overflow pipe 56 via the make-up water pipe 58, is supplied to the water conduit 16 of the toilet body 4 from the drain port 14, and is ultimately used as make-up water to form a seal in the toilet body 4.

Next, as shown in Figures 4 and 5, the flush water tank device 1 is equipped with a large/small flush switching device 60 provided within the water storage tank main body 22, and this large/small flush switching device 60 makes it possible to switch between either the large flush mode or the small flush mode.
The large/small flush switching device 60 also includes a small tank 62 for switching between large and small flushes provided within the water storage tank body 22 , and a large/small flush switching valve device 64 provided in this small tank 62 .

Next, Fig. 7 is a partial front cross-sectional view showing an enlarged view of the water storage tank main body and small tank of a flush water tank apparatus according to one embodiment of the present invention, and Fig. 8 is a perspective view of the small tank of a flush water tank apparatus according to one embodiment of the present invention, seen from diagonally above and to the front right.
In FIG. 8, a portion of the front wall surface (front partition wall 66a) of the small tank 62 is cut away so that the large/small cleaning switching valve device 64 inside the small tank 62 can be seen.
4 to 8, the small tank 62 has a side wall (partition wall 66) that extends in the vertical direction and partitions the small tank 62 into an external area S1 on the water storage tank body 22 side and an internal area S2 inside the small tank 62. This partition wall 66 forms a wall surface that extends in the vertical direction, and the small tank 62 as a whole is cup-shaped with its upper part open and surrounded on all four sides in the front-to-back and left-to-right directions, and the overall length of the small tank 62 in the left-to-right direction is longer than its overall length in the front-to-back direction.
Incidentally, within the external area S1 of the small tank 62 within the water storage tank body 22, the jet nozzle 46, the suction port 50a of the throat pipe 50, etc. are arranged.
Here, as shown in Figures 4 and 5, the external area S1 of the small tank 62 within the water storage tank main body 22 is the first water storage section within the water storage tank main body 22, and the bottom of this first water storage section is a water storage area in which the outlet 50b of the throat pipe 50 connected to the drain outlet 14 of the cleaning water tank device 1 is provided.
In addition, the internal area S2 of the small tank 62 within the water storage tank main body 22 serves as a second water storage section within the water storage tank main body 22, and is a water storage area in which the discharge outlet 50b of the throat pipe 50 connected to the drain outlet 14 of the cleaning water tank device 1 is not provided.

Next, as shown in Figures 4 to 8, the small tank 62, more specifically, comprises a small tank main body 68 arranged to extend from one left or right side (right side in Figures 4, 7 and 8) within the water storage tank main body 22 to the other longitudinal side (left side in Figures 4, 7 and 8), and a protrusion 70 that protrudes downward from the lower end of the other side (left side in Figures 4, 7 and 8) of the small tank main body 68 to the base surface 22a of the water storage tank main body 22.
4 and 8, the overall shape of the small tank is generally L-shaped in front view, extending from one of the left and right sides of the small tank main body 68 (the right side when the small tank main body 68 is viewed from the front) to the other side in the longitudinal direction (the left side when the small tank main body 68 is viewed from the front), and then protruding downward by a protrusion 70, so that the other sidewall in the left-right direction of the small tank main body 68 (the left sidewall when the small tank main body 68 is viewed from the front) and the left partition wall 70b on the other side in the left-right direction of the protrusion 70 form an integral wall surface in the vertical direction. In other words, the overall length of the protrusion 70 in the left-right direction is shorter than the overall length of the small tank main body 68 in the left-right direction.
In addition, the overall shape of the small tank 62 is not necessarily limited to a form in which the left side wall of the small tank main body 68 and the left partition wall 70b of the protrusion 70 in the left-right direction form an integral wall surface in the vertical direction, but may be a roughly L-shaped shape extending from one of the left and right sides of the small tank main body 68 to the other side in the longitudinal direction, then protruding downward by the protrusion 70, and then extending from one of the left and right sides of the small tank main body 68 to the other side in the longitudinal direction.
A switching opening 72 is provided in a partition wall (right partition wall 70a) on one of the left and right sides (the right side in Figs. 4 and 8) of the protruding portion 70.

Furthermore, as shown in Figures 6A, 6B and 7, the water tank main body 22 is provided with a base surface 22a on which the lowest bottom surface 70c of the protrusion 70 of the small tank 62 is located, and a lowest bottom surface 22b within the jet nozzle accommodating section H that protrudes downward in an area on one of the left and right sides of this base surface 22a (the area on the right side when the water tank main body 22 is viewed from the front).
As a result, the protrusion 70 of the small tank 62 is formed so as to protrude downward from the lower end of the small tank main body 68 to the base surface 22 a within the water storage tank main body 22 .

FIG. 9 is a cross-sectional view taken along line XI-XI of FIG.
As shown in FIGS. 4 and 7 to 9, the switching opening 72 of the protruding portion 70 of the small tank 62 is arranged so as to be directed toward the jet nozzle 46 of the jet pump unit 42 and the suction port 50 a of the throat pipe 50 .
In addition, in the area S1 within the water tank body 22 between the switching opening 72 of the small tank 62 and the suction port 50a of the jet nozzle 46 and the throat pipe 50, a straightening area (storage tank body side straightening area R1) is provided which straightens the cleaning water after it is discharged from the switching opening 72 of the small tank 62.

Next, as shown in Figures 4 to 9, the protrusion 70 of the small tank 62 is provided with a right-side partition wall 70a on one side (right side) of the left-right longitudinal direction in which a switching opening 72 is formed, and a left-side partition wall 70b provided opposite the other side (left side) of the right-side partition wall 70a in the left-right longitudinal direction.
In addition, within the internal region S2 of the small tank 62 formed between the first side wall surface, which is the wall surface of the right side partition wall 70a of the protrusion 70 of each of these small tanks 62, and the second side wall surface, which is the wall surface of the left side partition wall 70b of the protrusion 70, a straightening region (small tank internal straightening region R2) is provided which straightens the cleaning water before it is discharged from the switching opening 72 in the small tank 62.
Furthermore, the small tank internal flow straightening region R2 has a maximum width dimension L1 [mm] in the left-right direction that is set to be larger than a maximum width dimension W1 [mm] in the front-rear direction (L1>W1).

As shown in Figures 5 and 9, the maximum width dimension W1 in the front-to-rear short direction of the protrusion 70 of the small tank 62 is set to be smaller than the maximum width dimension W2 of each of the maximum width dimensions when the maximum width dimension of the internal area of the water storage tank body 22 is divided in half in the short direction (W1 < W2).

Next, as shown in FIGS. 4 and 7, the switching opening 72 of the small tank 62 is disposed above the suction port 50 a of the throat pipe 50 .
As shown in FIG. 9, the water tank body 22 has a longitudinal center axis C1 that bisects the maximum front-to-rear width dimension of the internal region S2 into a front region F0 and a rear region B0, and a transverse center axis C2 that bisects the maximum left-to-right width dimension of the internal region S2 into a left-to-right side region (right region R0) and a right-to-left side region (left region L0).
Furthermore, as shown in Figure 9, the protrusion 70 of the small tank 62 is located in a region (left side region L0) on one side of the short side center axis C2 of the water storage tank body 22 (right side region R0) where the suction port 50a of the throat pipe 50 is located, relative to a region on the other side of the short side center axis C2 (left side) where the suction port 50a is not located.
In addition, the protruding portion 70 of the small tank 62 is disposed in a region (front region F0) on the other side of the longitudinal central axis C1 of the water storage tank body 22 where the center O1 of the drain outlet 14 (center O1 of the outlet 50b of the throat pipe 50) is not disposed, relative to a region (rear region B0) on one side of the longitudinal central axis C1 of the water storage tank body 22 where the center O1 of the drain outlet 14 of the water storage tank body 22 (center O1 of the outlet 50b of the throat pipe 50) is disposed. As a result, the protruding portion 70 of the small tank 62 is disposed so as to be spaced apart from the suction port 50a of the throat pipe 50.

Next, as shown in Figure 9, the switching opening 72 is located within the water tank body 22 in a region (left side region L0) on the other side of the short side center axis C2 where the suction port 50a of the throat pipe 50 is not provided, compared to a region (right side region R0) on the left or right side of the short side center axis C2 where the suction port 50a is provided, and is located in a region (front region F0) forward of the longitudinal center axis C1.
9, the switching opening 72 has a central axis C3 that passes through the center O2 of the opening cross section and extends in the left-right longitudinal direction of the water storage tank body 22. The central axis C3 of the switching opening 72 is disposed to be spaced apart from the central axis C4 of the throat pipe 50 in the longitudinal direction to one side (front side) in the front-rear direction of the water storage tank body 22 in the plan view of FIG.

Next, the large/small flush switching valve device 64 will be described in detail with reference to FIGS. 4, 5, 7, 8, 10, and 11A to 11D.
First, Figure 10 is a partially enlarged perspective view showing an enlargement of the large/small flush switching valve device portion of the flush water tank apparatus according to one embodiment of the present invention shown in Figure 8. Also, Figures 11A to 11D are partially enlarged views showing an enlargement of the large/small flush switching valve device portion in the flush water tank apparatus according to one embodiment of the present invention.
In particular, Fig. 11A shows the open state of the switching valve body of the large/small flush switching valve device in the standby state before the start of the toilet flush operation and when the large flush operation of the toilet has begun. Fig. 11B shows the closed state of the switching valve body of the large/small flush switching valve device when the small flush operation of the toilet has begun. Fig. 11C shows the closed state of the switching valve body of the large/small flush switching valve device during a small flush of the toilet. Fig. 11D shows the state in which the switching valve body of the large/small flush switching valve device in the closed state has opened after the small flush of the toilet has ended and water is being supplied from the water supply valve device to the water storage tank main body.

As shown in Figures 4, 5, 7, 8, 10, and 11A to 11D, the large/small flush switching valve device 64 includes a switching valve body 74, a swinging member 76, a ball chain 78, and a pull-up lever 80.
First, as shown in FIGS. 10 to 11D, a bottom surface 68a of the small tank main body 68 is provided with a pair of switching valve support portions 68b, 68b arranged in a pair in the front-rear direction and protruding upward.
As shown in FIG. 10, each of these switching valve support portions 68b, 68b is provided in the vicinity of the upper portion of the switching opening 72 and is incorporated into a portion of each of the front partition wall 66a and the rear partition wall 66b of the small tank 62.
Furthermore, the switching valve support portions 68b, 68b are arranged parallel to each other in the front-rear direction, and hinge projections 68c that protrude in the front-rear direction are provided on the surfaces of the switching valve support portions 68b, 68b that face each other in the front-rear direction.

Next, as shown in FIG. 10, the switching valve body 74 of the large/small flush switching valve device 64 includes a rotating shaft portion 74a, a valve body main portion 74b, and a valve body auxiliary portion 74c.
10, the pivot shaft 74a of the switching valve body 74 is rotatably supported by the switching valve support parts 68b, 68b. More specifically, the pivot shaft 74a is a hinge part that forms hinge holes 74d that are rotatably connected to the hinge protrusions 68c, and the hinge axis C5 is provided to extend horizontally in the front-rear direction within the small tank 62.
Next, as shown in FIG. 10, a valve body portion 74b of the switching valve body 74 is provided integrally with a rotating shaft portion 74a, and enables the switching opening portion 72 to be opened and closed.
10, the valve element auxiliary portion 74c of the switching valve element 74 is provided integrally with the base end portion 74e of the valve element main body portion 74b. More specifically, this valve element auxiliary portion 74c is provided on the side opposite the base end portion 74e of the valve element main body portion 74b to the tip end portion 74f of the valve element main body portion 74b, and is provided on the side facing the valve element main body portion 74b with respect to the pivot shaft portion 74a.

10, the switching valve support portion 68b is provided near the upper portion of the switching opening 72. The valve body portion 74b of the switching valve body 74 is provided so that, when the valve is open, its lower end portion can rotate from near the bottom surface of the switching opening 72 toward an upward position around the central axis (hinge axis C5) of the hinge hole 74d of the rotating shaft portion 74a.
As a result, the valve body main portion 74b and the valve body auxiliary portion 74c of the switching valve body 74 are able to rotate integrally around the front-to-rear central axis of each hinge protrusion 68c and the central axis of each hinge hole 74d (hinge axis C5), allowing the valve body main portion 74b to be opened and closed relative to the switching opening 72.
The valve body main body 74b of the switching valve body 74 opens and closes the switching opening 72, thereby changing the amount of flush water supplied to the toilet body 4 through the jet pump unit 42, making it possible to switch between a large flush and a small flush.

Next, as shown in FIG. 10, each hinge hole 74d of the pivot shaft portion 74a of the switching valve body 74 is provided to extend horizontally in the front-rear direction within the second water storage portion of the water storage tank body 22 (the internal region S2 of the small tank 62).
Also, as shown in Figure 11A, the pivot shaft portion 74a of the switching valve body 74 is located on the first water storage section (external area S1 of the small tank 62) side of the water storage tank main body 22 relative to the switching opening 72 when viewed from the direction of the central axis C3 of the switching opening 72.
Furthermore, as shown in Figures 10 and 11A, the valve body main body 74b of the switching valve body 74 is provided with a protrusion 74g provided so as to protrude in a direction perpendicular to the axial direction of the pivot shaft portion 74a (the axial direction of the hinge axis C5), and a tip portion 74f provided in a direction perpendicular to the protruding direction of this protrusion 74g.
As a result, the center of gravity G (see FIG. 11A) of the valve body 74b is positioned so that in the open state, the valve body 74b maintains a posture extending horizontally from the protrusion 74g toward the tip 74f.

Next, as shown in FIGS. 10 to 11D, the valve body auxiliary portion 74c is provided with a plate-shaped weight member 74h.
This weight member 74h is detachably attached to the weight mounting portion Q of the valve body auxiliary portion 74c, which will be described in detail later, and functions as a valve body adjustment portion that adjusts the valve body main body portion 74b to maintain it in an open state when the large/small flush switching valve device 64 is switched to the large flush mode.

Next, as shown in FIGS. 10 to 11D, the swinging member 76 of the large/small flush switching valve device 64 is provided swingably on a swinging shaft 74i that protrudes forward and backward at the base end portion 74e of the switching valve body 74.
One end of a ball chain 78, which is a chain-like or linear (string-like) connecting member, is connected to a part of the swinging member 76. The other end of the ball chain 78 is connected to a part of a lifting lever 80 that is connected to the drive rotation shaft 32b of the operating device 32.
When the large flush mode of the toilet is started, the lifting lever 80 of the operating device 32 is operated to be lifted, whereby the ball chain 78 is lifted and the swinging member 76 is lifted.
In this embodiment, a form in which a ball chain 78 is used as a chain-shaped or linear (string-shaped) connecting member is described; however, a chain-shaped connecting member or a wire-shaped connecting member in a form other than the ball chain 78 may also be used.

Furthermore, the swinging member 76 is also connected to the valve body auxiliary portion 74c of the switching valve body 74 in a manner that allows the connection to be released.
As shown in Figures 10 and 11, for example, when the valve body main portion 74b and the valve body auxiliary portion 74c of the switching valve body 74 are in an open state with the valve body 74 in a substantially horizontal position, the oscillating member 76 is positioned on the bottom surface 68a of the small tank main body portion 68 so as to support the valve body auxiliary portion 74c of the switching valve body 74 from below.

As a result, the switching valve body 74 of the large/small flush switching valve device 64 is connected to the drive rotation shaft 32 b of the water supply valve device 28 via the swinging member 76 , the ball chain 78 , and the pull-up lever 80 .
For example, as shown in FIG. 11A, in the standby state before the start of the toilet flushing operation, the ball chain 78 is in a slack state, and the valve body main body 74b of the switching valve body 74 is in a horizontal position, opening the switching opening 72.
As shown in FIG. 11A, when the large-flush operation of the toilet has started, the user rotates the operating lever 32a in one direction, and the drive rotation shaft 32b is rotated in one direction.
However, since the pull-up lever 80 does not rotate integrally with the drive shaft 32b and remains stationary, the ball chain 78 is not pulled up by the pull-up lever 80 and remains slack. As a result, the valve body 74b of the switching valve 74 maintains the switching opening 72 open.

Next, as shown in FIG. 11B, when the small flush operation of the toilet has started, the user rotates the operating lever 32a in the other direction, and the drive rotation shaft 32b is rotated in the other direction.
As a result, the pull-up lever 80 rotates integrally with the drive rotation shaft 32 b , and the ball chain 78 is pulled up by the pull-up lever 80 .
Then, by pulling up this ball chain 78, the oscillating member 76 is pulled up so that its tip is raised, and it oscillates from the initial position in the standby state (see Figure 11A) around the oscillating axis 74i in the valve closing direction while connected to the valve body auxiliary part 74c of the switching valve body 74 (see Figure 11B).
As a result, the valve body main portion 74b and valve body auxiliary portion 74c of the switching valve body 74, as well as the entire oscillating member 76, are in an upright position, and the valve body main portion 74b of the switching valve body 74 is in a state in which it closes the switching opening 72 (see Figure 11B).
At this time, as shown in Figure 11B, the water level WL1 in the water storage tank body 22 in the external area S1 of the small tank 62 is lower than the water level WL2 in the internal area S2 of the small tank 62, and the water pressure P2 in the internal area S2 of the small tank 62 is higher than the water pressure P2 in the water storage tank body 22 in the external area S1 of the small tank 62 (P2 > P1), so that the water level difference ΔWL (= WL2 - WL1) and the water pressure difference ΔP (= P2 - P1) cause the valve body main body portion 74b of the switching valve body 74 to be maintained in a closed state.

Next, as shown in FIG. 11C, during a small flush of the toilet, the pull-up lever 80 rotates to return to its original state before it was pulled up (the standby state in FIG. 11A), and the drive rotation shaft 32b also rotates in one direction together with the pull-up lever 80.
At this time, the ball chain 78 is released from the pulled-up state, and the reaction force from the ball chain 78 also causes the swinging member 76 to be disconnected from the valve body auxiliary portion 74c of the switching valve body 74. As a result, the swinging member 76 swings in a direction returning to the standby state independently of the valve body auxiliary portion 74c, and assumes a horizontal position (see FIG. 11C).
At this time, as shown in Figure 11C, the water level WL1 in the water storage tank body 22 in the external area S1 of the small tank 62 is lower than the water level WL2 in the internal area S2 of the small tank 62, and the water pressure P2 in the internal area S2 of the small tank 62 is higher than the water pressure P2 in the water storage tank body 22 in the external area S1 of the small tank 62 (P2 > P1), so that the water level difference ΔWL (= WL2 - WL1) and the water pressure difference ΔP (= P2 - P1) cause the valve body main body portion 74b of the switching valve body 74 to be maintained in a closed state.
In addition, during the toilet's small flush, the oscillating member 76 rotates (oscillates) independently of the valve body auxiliary portion 74c of the switching valve body 74, thereby preventing the ball chain 78 itself from interfering with the valve body main portion 74b or the valve body auxiliary portion 74c of the switching valve body 74 and causing the valve to open, and the valve body main portion 74b of the switching valve body 74 is maintained in a closed state.
8, a small communication hole 68d is provided in the bottom surface 68a on one of the left and right sides (the right side when the small tank body 68 is viewed from the front) of the small tank body 68, which connects the internal area S2 of the small tank 62 with the external area S1 (inside the water storage tank body 22). As a result, the water level WL2 of the flush water in the small tank 62 is in a state in which the switching opening 72 is closed by the valve body body 74b of the switching valve body 74, but is slightly lowered and is higher than the water level WL1 in the water storage tank body 22 (WL2>WL1) (see FIG. 11C).
Incidentally, during the full-flush operation of the toilet, flush water present in a position far from the switching opening 72 in the small tank 62 is discharged from the small communicating hole 68d into the external area S1 of the small tank 62, thereby making it possible to reduce the amount of flush water remaining in the small tank 62.

Next, as shown in FIG. 11D, when the water level WL1 of the flush water in the water storage tank body 22 drops to the water level DWL1, the flow path switching valve 48 is switched to the water storage flow path 54, the flush water of the jet nozzle 46 is switched from supplying water to the throat pipe 50 to supplying water to the water storage tank body 22, the small flush of the toilet is completed, and water is supplied to the water storage tank body 22.
As a result, the water level WL1 in the external area S1 of the small tank 62 (the water level in the water storage tank body 22) rises and becomes the same water level as the water level WL2 of the cleaning water in the small tank 62 (WL1 = WL2), and the water level difference ΔWL (= WL2 - WL1) and the water pressure difference ΔP (= P2 - P1) become 0.
At this time, since the valve body auxiliary portion 74c provided on the swinging member 76 side of the switching valve body 74 is provided with a weight member 74h (see Figs. 10 and 11D), the balance between the weight of this weight member 74h and the center of gravity G of the valve body main portion 74b of the switching valve body 74 is adjusted in the direction of the open valve state. As a result, the valve body main portion 74b of the switching valve body 74 rotates to a horizontal position and is in the open valve state.
In addition, a weight member 74h is provided in the valve body auxiliary portion 74c of the switching valve body 74, so that when the cleaning water in the small tank 62 is discharged from the switching opening 72 to the external area S1 of the small tank 62 during the large flush operation, the flow of the cleaning water in the small tank 62 is prevented from accidentally causing the valve body main portion 74b of the switching valve body 74 to enter a closed state.
Furthermore, as shown in FIG. 6B, within the jet nozzle accommodating section H of the water storage tank main body 22, the flow path switching valve 48 is switched to the tank water storage flow path 54, so that the cleaning water jetted from the jet nozzle 46 is supplied into the water storage tank main body 22 without flowing into the throat pipe 50.

Next, with reference to FIG. 10 and FIG. 12 to FIG. 13B, the details of the weight attachment portion Q in the valve body auxiliary portion 74c of the switching valve body 74 to which the weight member 74h is attached will be described.
First, Fig. 12 is an enlarged plan view showing an enlarged weight mounting portion of the valve body auxiliary part of the switching valve body in a large/small flush switching valve device of a flush water tank apparatus according to one embodiment of the present invention. Also, Fig. 13A is a cross-sectional view taken along line XIIIA-XIIIA in Fig. 12. Furthermore, Fig. 13B is a cross-sectional view similar to Fig. 13A showing the weight mounting portion of the valve body auxiliary part of the switching valve body in a large/small flush switching valve device of a flush water tank apparatus according to one embodiment of the present invention, and shows the state when the weight member is attached to or detached from the weight mounting portion.

10 and 12 to 13B, the weight mounting portion Q of the valve body auxiliary portion 74c of the switching valve body 74 has a weight mounting surface 82 provided on the tip side (right side in the left-right longitudinal direction) of the upper surface of the valve body auxiliary portion 74c in the horizontal state. The weight mounting portion Q also has a holding portion 84 provided on the weight mounting surface 82 and holding the weight member 74h from the side so that the weight member 74h can slide in the longitudinal direction of the valve body auxiliary portion 74c.
Next, the retaining portion 84 includes a pair of base end front and rear retaining protrusions 84a, 84a provided on the base end side (left side in the left-right direction in Figure 12) and both ends in the width direction (front-to-back direction) of the weight mounting surface 82, and a pair of tip end side front and rear retaining protrusions 84b, 84b provided on the tip end side (left side in the left-right direction in Figure 12) and both ends in the width direction (front-to-back direction) of the weight mounting surface 82.
In addition, the holding portion 84 includes a pair of holding frames 84c, 84c provided at both ends in the width direction between each of the base end front and rear holding protrusions 84a and each of the tip end front and rear holding protrusions 84b of the weight mounting surface 82, and a single base end central holding protrusion 84d provided on the base end side of each of the base end front and rear holding protrusions 84a, 84a on the weight mounting surface 82.

Furthermore, the holding portion 84 is provided with a flexible hook portion 86 that is provided in the center in the width direction on the tip side of the weight attachment surface 82 and faces the base end side central holding protrusion 84d.
In this hook portion 86, when the weight member 74h is attached to or detached from the weight mounting portion Q, elastic bending deformation (elastic bending deformation with a deflection amount δ shown in FIG. 13B) is possible in the out-of-plane direction (the up-down direction in FIG. 13B) relative to the weight mounting surface 82 in response to the load acting from the weight member 74h.
The upper surface of the hook portion 86 forms a part of the weight mounting surface 82, and the tip of the upper surface of the hook portion 86 is provided with a holding protrusion (tip side central holding protrusion 86a) that protrudes upward.
Incidentally, when the weight member 74h is inserted into the weight mounting portion Q from the tip side and mounted at a predetermined mounting position on the weight mounting surface 82, both left and right end faces of the plate-like weight member 74h are held by the base end side central holding protrusion 84d and the tip end side central holding protrusion 86a, and both front and rear end faces of the weight member 74h are held by the front and rear base end side central holding protrusions 84d, 84d, the front and rear tip end side central holding protrusions 86a, 86a, and the front and rear holding frames 84c, 84c. Also, parts of the front and rear ends of the upper surface of the weight member 74h are held by the front and rear holding frames 84c, 84c.

Next, as shown in Figures 12 to 13B, a concave curved surface 86b is formed on the surface of hook portion 86 opposite to weight mounting surface 82 (the lower surface of hook portion 86), and the vertical thickness d between base end E1 and tip end E2 of hook portion 86 (thickness d between the upper and lower surfaces of hook portion 86) is partially reduced.
As a result, even if the hook portion 86 elastically deforms when the weight member 74h is attached or detached from the weight mounting portion Q, the stress generated at the base end E1 of the hook portion 86 is dispersed, thereby avoiding stress concentration at the base end E1 of the hook portion 86 and reducing damage and load to the hook portion 86.

12, a pair of front and rear slits 88 (a front slit 88a and a rear slit 88b) are formed to extend in the left-right direction on both the front and rear sides of the hook portion 86. The base end (left end) of each slit 88 essentially forms part of the base end E1 of the hook portion 86.
As a result, the base end E1 of the hook portion 86 is connected to the adjacent weight mounting surfaces 82 in the front and rear via each slit 88a, 88b by curved surfaces with at least two radii of curvature (a first curved surface 90 with a first radius of curvature ρ1 and a second curved surface 92 with a second radius of curvature ρ2).
Here, as shown in FIG. 12, the first curved surface 90 having a first radius of curvature ρ1 is a proximal curved surface 90 formed on the base end E1 side of the hook portion 86 (proximal side relative to the base end E1 of the hook portion 86) in the curved surface forming the end on one of the left and right sides (left side) of each slit 88a, 88b.
On the other hand, as shown in FIG. 12, the second curved surface 92 having the second radius of curvature ρ2 is a distal curved surface 92 formed on the side of the weight mounting surface 82 (distal to the base end E1 of the hook portion 86) adjacent to the front and rear of the base end E1 of the hook portion 86 in the curved surface forming the end portion on one of the left and right sides (left side) of each slit 88a, 88b.
As shown in FIG. 12, the first radius of curvature ρ1 of the first curved surface 90 in plan view is set to be larger than the second radius of curvature ρ2 of the second curved surface 92 (ρ1>ρ2).
As a result, even if the hook portion 86 elastically deforms when the weight member 74h is attached or detached from the weight mounting portion Q, the first radius of curvature ρ1 of the first curved surface 90 proximal to the base end E1 of the hook portion 86 is set relatively large, so that the stress generated at the base end E1 of the hook portion 86 is dispersed, thereby preventing stress concentration at the base end E1 of the hook portion 86 and reducing damage and load to the hook portion 86.

As shown in FIG. 4, the water level WL in the water storage tank body 22 is at the following position.
First, the water level DWL1 indicates the lowest water level in the area S1 in the water tank body 22 when each of the large and small flushes of the toilet is completed, as shown in Figure 4, and is located below the lower end of the switching opening 72.
Next, as shown in Figure 4, the water level DWL1 is the lowest water level in area S1 in the water storage tank body 22 when each of the large and small flushes is completed, and the water level DWL2 indicates the lowest water level in area S2 in the small tank 62 when the small flush is completed.
4, the water level WL0 is the stop water level (highest water level) in the initial state (standby state) of flush water stored in the storage tank body 22. This stop water level WL0 indicates the normal stop water level before or after use of the flush toilet 2, and is located slightly above the water level DWL2.
Incidentally, the water level WL1 shown in FIG. 4 is the water level in the area S1 in the water storage tank body 22 when the water level is decreasing or increasing, and is higher than the minimum water level DWL1 and lower than the maximum water level WL0.
The water level WL2 shown in FIG. 4 is the water level in the area S2 in the small tank 62 when the water level is decreasing or increasing, and is higher than the minimum water level DWL2 and lower than the maximum water level WL0.

Next, the operation of the flush water tank assembly 1 according to one embodiment of the present invention will be described with reference to FIGS.
FIG. 14 is a flow chart showing the flow of operation of a flush water tank assembly according to one embodiment of the present invention.
As shown in FIG. 14, when performing either the large flush or small flush of the flush toilet 2, first, in step S1, the user rotates the operating lever 32a of the operating device 32.
Specifically, when the operating lever 32a is rotated in one direction (for example, toward the front (large flush side) when looking at the flush water tank device 1 from the front), the large flush mode is started, and when the operating lever 32a is rotated in the other direction (for example, toward the rear (small flush side) when looking at the flush water tank device 1 from the front), the small flush mode is started.

Next, the large flush mode will be described below.
When the large flush mode is started, the drive rotation shaft 32b of the operating device 32 is rotated in one direction by rotating the operating lever 32a, but the lifting lever 80 of the large/small flush switching valve device 64 remains stationary and does not rotate integrally with the drive rotation shaft 32b.
As a result, the ball chain 78 is not pulled up by the pull-up lever 80 and is in a slack state, so that the swinging member 76 is not pulled up by the ball chain 78 .
Furthermore, the weight of the weight member 74h causes the valve body auxiliary portion 74c of the switching valve body 74 to assume a substantially horizontal position on the swinging member 76, pressing the swinging member 76 against the bottom surface 68a of the small tank body 68. This causes the valve body main portion 74b of the switching valve body 74 to maintain a state in which the switching opening 72 is open (see FIG. 11A).

Next, in step S2 of FIG. 14, the poppet valve 34 of the water supply valve device 28 is opened by the rotation of the drive rotation shaft 32b of the operating device 32 in one direction.
At this time, the water storage tank body 22 is filled with flushing water near the stop water level (highest water level) WL0, so the flow path switching valve 48 of the jet pump unit 42 is switched to the toilet flushing flow path 52 due to the buoyancy of the flushing water in the water storage tank body 22, and the suction port 50a of the throat pipe 50 is opened by the flow path switching valve 48.
Then, in step S4 of FIG. 14, when the poppet valve 34 of the water supply valve device 28 opens, in step S4, wash water flows out of the pressure chamber 30c of the water supply valve device 28, and the pressure in the pressure chamber 30c decreases.
As a result, the main valve body 30a of the water supply valve (main valve 30) of the water supply valve device 28 moves away from the main valve seat 30b, opening the valve, and the cleaning water supplied to the water supply valve device 28 from the water supply pipe 24 via the constant flow valve 26 is supplied from the water supply valve device 28 into the water supply pipe 44 downstream.
Thereafter, the flushing water in the water supply pipe 44 is supplied to the jet nozzle 46 of the jet pump unit 42 via the vacuum breaker valve 40. The flushing water supplied to this jet nozzle 46 is sprayed toward the suction port 50a of the throat pipe 50 via the toilet flushing flow path 52 of the flow path switching valve 48, and jet spouting begins (see FIG. 6A).
In addition, when jet water spouting begins, the forceful flow of cleaning water sprayed from the jet nozzle 46 toward the suction port 50a of the throat pipe 50 creates a negative pressure that directly draws in the surrounding cleaning water, such as near the suction port 50a of the throat pipe 50, without relying on other mechanical elements such as a pump, and this negative pressure is used to transport the cleaning water in the water storage tank body 22 that has been sucked into the throat pipe 50 toward the toilet body 4, creating a so-called "jet pump action."

Furthermore, if the jet water spouting continues, in step S5 of FIG. 14, the water level WL1 in the water storage tank body 22 drops, so that the float 36 of the water supply valve device 28 descends and the float-side pilot valve 38 opens.
At this time, since the internal area S2 of the small tank 62 and the external area S1 (area S1 within the water storage tank body 22) are connected via the open switching opening 72 and the small communicating hole 68d of the small tank 62, the water level WL2 within the small tank 62 also decreases together with the water level WL1 within the water storage tank body 22.
Then, when the water level WL1 in the water storage tank main body 22 and the water level WL2 in the small tank 62 drop to the minimum water level DWL1, the buoyancy caused by the cleaning water in the water storage tank main body 22 acting on the flow path switching valve 48 of the jet pump unit 42 also decreases.
As a result, the flow path switching valve 48 of the jet pump unit 42 is switched to the tank water storage flow path 54, and the suction port 50a of the throat pipe 50 is closed by the flow path switching valve 48 (see Figure 6B).
Therefore, flush water jetted from the jet nozzle 46 is supplied into the water storage tank body 22 from the tank water storage flow path 54 of the flow path switching valve 48. At the same time, a portion of this flush water is replenished into the overflow pipe 56 from the make-up water pipe 58, and then replenished to the toilet body 4 side.
This flush water supplied to the toilet body 4 is used when forming a water seal in the toilet body 4.

14, when the water level WL1 in the water storage tank body 22 rises due to water supply from the tank water storage flow path 54 of the flow path switching valve 48 into the water storage tank body 22, the float 36 of the water supply valve device 28 rises due to the buoyancy of the flush water at the rising water level WL1, and the float-side pilot valve 38 closes. Since the small tank 62 is connected through the opened switching opening 72 and the small communication hole 68d, the water level WL2 in the small tank 62 also rises together with the water level WL1 in the water storage tank body 22.
As a result, the pressure in the pressure chamber 30c of the water supply valve device 28 again becomes the primary flow path pressure α, the main valve body 30a moves toward the main valve seat 30b, and finally the main valve 30 is closed (water stop state).
At this time, in step S8 of Figure 14, since the water storage tank body 22 is filled with flushing water at the stop water level (highest water level) WL0, the flow path switching valve 48 of the jet pump unit 42 is again switched to the toilet flushing flow path 52 due to the buoyancy of the flushing water in the water storage tank body 22, and the suction port 50a of the throat pipe 50 is opened by the flow path switching valve 48.
Then, in step S9 of FIG. 14, water storage in the water storage tank body 22 is completed, whereby the large-flush mode is completed and the device goes into a standby state (see FIG. 11A).

Next, the small-flush mode will be described below.
First, in step S1 of FIG. 14, when the small-flush mode has been started, the drive rotation shaft 32b of the operation device 32 is rotated in the other direction by rotating the operation lever 32a.
Then, in step S2 of Figure 14, the poppet valve 34 of the water supply valve device 28 opens, the flow path switching valve 48 of the jet pump unit 42 is switched to the toilet flushing flow path 52, and the suction port 50a of the throat pipe 50 is opened by the flow path switching valve 48.

Next, in step S3 of FIG. 14, the pull-up lever 80 of the large/small flush switching valve device 64 moves in conjunction with the drive rotation shaft 32b (rotates integrally with the drive rotation shaft 32b), and the ball chain 78 is pulled up by the pull-up lever 80.
Then, as the ball chain 78 is pulled up, the oscillating member 76 oscillates around the oscillating axis 74i of the switching valve body 74 so that its tip rises, and the switching valve body 74 and the oscillating member 76 as a whole assume an upright position (see Figure 11B).
Furthermore, the valve body portion 74b of the switching valve body 74 is in a state of closing the switching opening 72 by being in a vertically raised position.

Next, as in the large-flush mode, in step S4 of FIG. 14, the water supply valve (main valve 30) of the water supply valve device 28 opens, cleaning water is sprayed from the jet nozzle 46 toward the suction port 50a of the throat pipe 50, and jet spouting begins (see FIG. 6A).
Then, as in the large-flush mode, in step S5 of FIG. 14, as the jet water spouting continues, the water level WL1 in the water tank body 22 drops, causing the float 36 of the water supply valve device 28 to descend and the float-side pilot valve 38 to open.

11B and 11C, the water level WL1 in the water storage tank body 22 of the external area S1 of the small tank 62 is lower than the water level WL2 in the internal area S2 of the small tank 62, and the water pressure P2 in the internal area S2 of the small tank 62 is higher than the water pressure P2 in the water storage tank body 22 of the external area S1 of the small tank 62 (P2>P1). The water level difference ΔWL (=WL2-WL1) and the water pressure difference ΔP (=P2-P1) maintain the valve body portion 74b of the switching valve 74 in a closed state.

Next, in step S6 of FIG. 14, when the water level WL1 in the water storage tank body 22 further drops to the minimum water level DWL1 and the water level WL2 in the small tank 62 drops to the minimum water level DWL2, the small flush of the toilet ends (see FIG. 11D).
At this time, as shown in Figure 6B, in the jet nozzle housing section H of the water storage tank body 22, the flow path switching valve 48 is switched to the tank water storage flow path 54, so that flush water jetted from the jet nozzle 46 is supplied into the water storage tank body 22 without flowing into the throat pipe 50. At the same time, a portion of this flush water is replenished from the make-up water pipe 58 into the overflow pipe 56, and then replenished to the toilet body 4 side.
Thereafter, as water is further supplied into the water storage tank main body 22, the water level WL1 in the external area S1 of the small tank 62 (the water level within the water storage tank main body 22) rises, and the water level WL2 of the cleaning water in the small tank 62 and the water level WL1 within the water storage tank main body become the same water level (WL1 = WL2). As a result, the water level difference ΔWL (= WL2 - WL1) and the water pressure difference ΔP (= P2 - P1) become zero, and the water level difference and water pressure difference that maintain the valve body main body 74b of the switching valve body 74 in a closed state disappear. Therefore, the valve body auxiliary portion 74c of the switching valve body 74 rotates toward the oscillating member 76 to assume a horizontal posture due to the balance between the weight of the weight member 74h (see Figures 10 and 11D) and the center of gravity G of the valve body main body 74b of the switching valve body 74, and the valve body main body 74b, which rotates integrally with this valve body auxiliary portion 74c, becomes in an open state.

14, the water level WL1 in the water storage tank body 22 rises due to water being supplied from the tank water storage flow path 54 of the flow path switching valve 48 into the water storage tank body 22, and the float 36 of the water supply valve device 28 rises due to the buoyancy caused by the flush water at this raised water level WL1, closing the float-side pilot valve 38. This closes the main valve 30 of the water supply valve device 28, and the water supply is stopped.
At this time, the small tank 62 is in communication with the open switching opening 72 and the small communication hole 68d, so the water level WL2 in the small tank 62 also rises together with the water level WL1 in the water storage tank body 22.
Furthermore, as in the large-flush mode, in step S8 of FIG. 14, since the water storage tank body 22 is filled with flush water at the stop water level (highest water level) WL0, the flow path switching valve 48 of the jet pump unit 42 is again switched to the toilet flushing flow path 52 due to the buoyancy of the flush water in the water storage tank body 22, and the suction port 50a of the throat pipe 50 is opened by the flow path switching valve 48.
Then, in the same manner as in the large-flush mode, when water storage in the water storage tank body 22 is completed in step S9 in FIG. 14, the small-flush mode is completed and the standby state is entered (see FIG. 11A).

Next, the operation of the flush water tank apparatus 1 according to one embodiment of the present invention will be described with reference to FIGS.
According to the flush water tank device 1 of one embodiment of the present invention described above, when starting to flush the toilet, for example, when the operating device 32 is switched to large flush mode, the valve body main body 74b of the switching valve body 74 of the large/small flush switching valve device 64 in the large/small flush switching device 60 opens, and the switching opening 72 of the partition wall 66 that separates the first water storage section (external area S1 of the small tank 62) and the second water storage section (internal area S2 of the small tank 62) of the water storage tank body 22 is opened.
At this time, the position of the center of gravity G of the entire switching valve body 74 can be adjusted by the valve body adjustment section (weight member 74h) provided in the valve body auxiliary section 74c of the switching valve body 74 of the large/small flush switching valve device 64 so that the valve body main body section 74b in the large flush mode is maintained in the open state.
This makes it possible to prevent the valve body main portion 74b of the switching valve body 74 of the large/small flush switching valve device 64 from accidentally going into a closed state while the large flush mode of the toilet is being executed.
Therefore, when the large flush mode of the toilet is being executed, it is possible to prevent a shortage of flush water supplied from the water storage tank body 22 to the toilet body 4, which would result in a decrease in toilet flushing performance during the large flush.
On the other hand, when starting to flush the toilet, for example, if the operating device 32 is switched to the small flush mode, the valve body main portion 74b and the valve body auxiliary portion 74c of the switching valve body 74 of the large/small flush switching valve device 64 are maintained in a closed valve state due to the water level difference ΔWL (= WL2 - WL1) and water pressure difference ΔP (= P2 - P1) of the flush water stored in the first water storage section (external area S1 of the small tank 62) and the second water storage section (internal area S2 of the small tank 62) of the water storage tank body 22, respectively.
Therefore, when the small flush mode of the toilet is being executed, the valve body main body 74b of the switching valve body 74 of the large/small flush switching valve device 64 may mistakenly be opened, causing the flush water stored in the internal area S2 of the small tank 62 of the water storage tank body 22 to be discharged from the switching opening 72 into the external area S1 of the small tank 62, thereby avoiding the risk that the small flush mode of the toilet may not be executed correctly.
As a result, when the toilet is in the large flush mode, the valve body main body 74b of the switching valve body 74 of the large/small flush switching valve device 64 can be reliably maintained in an open state, and when the toilet is in the small flush mode, the valve body main body 74b of the switching valve body 74 can be reliably maintained in a closed state, so that each of the toilet's large and small flush modes can be accurately executed.

Furthermore, according to the flush water tank apparatus 1 of this embodiment, in view of the recent diversification of designs for flush water tank apparatuses 1 and flush toilets 2, there is a demand for the overall size of the water storage tank body 22 to be reduced, and in the case of a small tank 62 that is not provided with an outlet (drain outlet 14, outlet 50b of throat pipe 50) in the water storage tank body 22, it is desirable to use the stored flush water in a way that reduces residual water as much as possible.
Furthermore, if the switching valve support portion 68b of the small tank main body portion 68 is provided at the bottom of the switching opening 72, when the cleaning water in the small tank 62 is discharged from the switching opening 72 with the valve body portion 74b of the switching valve body 74 open, there is an increased risk that something that will hinder the discharge of the cleaning water, such as part of the pivot shaft portion 74a or valve body portion 74b of the switching valve body 74 of the large/small cleaning switching valve device 64 remaining near the bottom of the switching opening 72.
This can cause residual water to remain in the small tank 62, resulting in a problem of reduced drainage efficiency of the switching opening 72.
In contrast, in the flush water tank apparatus 1 of this embodiment, a switchover valve support portion 68b that rotatably supports the pivot shaft portion 74a of the switchover valve body 74 of the large/small flush switchover valve device 64 is provided near the upper portion of the switchover opening 72, and the valve body main portion 74b of the switchover valve body 74 is provided so that, when the valve is open, its lower end portion can pivot from near the bottom surface of the switchover opening 72 toward an upward position centered on the pivot shaft portion 74a. As a result, no space is required near the bottom surface of the switchover opening 72 for providing the pivot shaft portion 74a of the switchover valve body 74.
Therefore, when the valve body main body 74b of the switching valve body 74 is open and the cleaning water in the small tank 62 is discharged from the switching opening 72, there is nothing near the bottom of the switching opening 72 to hinder the discharge of the cleaning water, so the amount of residual water in the small tank 62 can be reduced.
Furthermore, when the valve body main portion 74b of the switching valve body 74 is open and its lower end rotates from near the bottom surface of the switching opening 72 toward an upward position around the pivot shaft portion 74a, even if gravity or water pressure acts on the valve body main portion 74b to rotate it in the closing direction, the valve body adjustment portion (weight member 74h) provided in the valve body auxiliary portion 74c can be adjusted to maintain the valve body main portion 74b in the open state.
Therefore, it is possible to prevent the valve body main body 74b of the switching valve body 74 of the large/small flush switching valve device 64 from accidentally going into a closed state while the large flush mode of the toilet is being executed. This makes it possible to prevent a shortage of flush water supplied from the water storage tank body 22 to the toilet body 4, which would otherwise cause a decrease in toilet flushing performance during large flushing.

Furthermore, according to the flush water tank apparatus 1 of this embodiment, the weight member 74h is provided as a valve body adjustment portion on the valve body auxiliary portion 74c of the switching valve body 74 of the large/small flush switching valve device 64. This makes it possible to adjust the position of the center of gravity G of the entire switching valve body 74 of the large/small flush switching valve device 64 so that the valve body main body portion 74b of the switching valve body 74 in the large flush mode is maintained in the open valve state.
Therefore, when the operating device 32 is switched to the large flush mode, the weight of the weight member 74h of the valve body adjustment section causes both the valve body main body 74b and the valve body auxiliary portion 74c of the switching valve body 74 to rotate in the valve opening direction around the pivot shaft portion 74a, and the valve body main body 74b can be adjusted to maintain the open state.
Therefore, when the large flush mode of the toilet is being executed, it is possible to prevent the valve body main body 74b of the switching valve body 74 of the large/small flush switching valve device 64 from accidentally entering a closed state, thereby ensuring that the large flush of the toilet is executed.

Furthermore, according to the flush water tank apparatus 1 of this embodiment, the weight mounting portion Q of the valve body auxiliary portion 74c of the switching valve body 74 is provided with a holding portion 84 that holds the plate-shaped weight member 74h from the side so that it can slide in the longitudinal direction of the valve body auxiliary portion 74c. This holding portion 84 is provided on the tip side of the weight mounting surface 82 and has a hook portion 86 that is capable of elastic deformation (elastic bending deformation with a deflection amount δ shown in FIG. 13B) in the out-of-plane direction relative to the weight mounting surface 82 when the weight member 74h is attached or detached.
In addition, on the surface of the hook portion 86 opposite the weight mounting surface 82 (the lower surface of the hook portion 86), a concave curved surface 86b is formed so as to partially reduce the thickness d between the base end E1 and the tip end E2 of the hook portion 86 (the thickness d between the upper and lower surfaces of the hook portion 86).
This allows the stress generated at the base end E1 of the hook portion 86 when the weight member 74h is attached or detached to be dispersed, thereby making it possible to avoid stress concentration at the base end E1 of the hook portion 86.
Therefore, damage to the hook portion 86 due to stress concentration can be prevented, and the weight member 74h can be securely attached and held to the weight attachment portion Q of the valve body auxiliary portion 74c.
Therefore, since the weight member 74h can be securely provided as a valve body adjustment part on the valve body auxiliary part 74c of the switching valve body 74 of the large/small flush switching valve device 64, the position of the center of gravity G of the entire large/small flush switching valve device 64 can be adjusted so that the valve body main body part 74b in the large flush mode is maintained in the open state.
Therefore, when the operating device 32 is switched to the large flush mode, the weight of the valve body adjustment section causes both the valve body main body 74b and the valve body auxiliary portion 74c of the switching valve body 74 of the large/small flush switching valve device 64 to rotate in the valve opening direction around the pivot shaft portion 74a, and the valve body main body 74b can be adjusted to maintain the open state.
As a result, when the large flush mode of the toilet is being executed, it is possible to prevent the valve body main body 74b of the switching valve body 74 of the large/small flush switching valve device 64 from accidentally entering a closed state, thereby ensuring that the large flush of the toilet is executed.

Furthermore, according to the flush water tank device 1 of this embodiment, in the weight mounting portion Q of the valve body auxiliary portion 74c of the switching valve body 74, the base end E1 of the hook portion 86 is connected to the weight mounting surface 82 adjacent to the base end E1 of the hook portion 86 in the planar view shown in Figure 12 by at least two first curved surfaces (proximal curved surfaces 90) having a first radius of curvature ρ1 and a second curved surface (distal curved surface 92) having a second radius of curvature ρ2.
In addition, the first radius of curvature ρ1 of the proximal curved surface 90 formed on the base end E1 side of the hook portion 86 is set to be larger than the second radius of curvature ρ2 of the distal curved surface 92 formed on the weight mounting surface 82 side adjacent to the base end E1 of the hook portion 86 (ρ1 > ρ2).
This makes it possible to disperse the stress generated at the base end E1 of the hook portion 86 when the weight member 74h is attached or detached to the weight mounting portion Q of the valve body auxiliary portion 74c of the switching valve body 74, or when the weight member 74h is attached to the weight mounting portion Q of the valve body auxiliary portion 74c.
Therefore, stress concentration at the base end E1 of the hook portion 86 can be avoided, thereby preventing damage to the hook portion 86 due to stress concentration, and the weight member 74h can be securely attached and held to the weight mounting portion Q of the valve body auxiliary portion 74c.
Therefore, since the weight member 74h can be securely provided as a valve body adjustment part on the valve body auxiliary part 74c of the switching valve body 74 of the large/small flush switching valve device 64, the position of the center of gravity G of the entire large/small flush switching valve device 64 can be adjusted so that the valve body main body part 74b in the large flush mode is maintained in the open state.
Therefore, when the operating device 32 is switched to the large flush mode, the weight of the valve body adjustment section causes both the valve body main body 74b and the valve body auxiliary portion 74c of the switching valve body 74 of the large/small flush switching valve device 64 to rotate in the valve opening direction around the pivot shaft portion 74a, and the valve body main body 74b can be adjusted to maintain the open state.
As a result, when the large flush mode of the toilet is being executed, it is possible to prevent the valve body main body 74b of the switching valve body 74 of the large/small flush switching valve device 64 from accidentally entering a closed state, thereby ensuring that the large flush of the toilet is executed.

Also, according to the flush water tank apparatus 1 of this embodiment, the pivot shaft portion 74a of the switching valve body 74 of the large/small flush switching valve device 64 is a hinge portion that forms hinge holes 74d that are rotatably connected to each hinge protrusion 68c. Also, the pivot shaft portion 74a of this switching valve body 74 can be provided so that the hinge axis C5 of the hinge hole 74d extends horizontally in the front-to-rear direction within the small tank 62, and can be provided on the first water storage portion (external area S1 of the small tank 62) side of the switching opening 72 when viewed from the direction of the central axis C3 of the switching opening 72.
Furthermore, in the valve body main body 74b of the switching valve body 74 of the large/small flush switching valve device 64, a protrusion 74g is provided so as to protrude in a direction perpendicular to the axial direction of the pivot shaft portion 74a, and a tip portion 74f is provided in a direction perpendicular to the protruding direction of this protrusion portion 74g, so that the center of gravity G can be positioned so that the valve body main body 74b in the open state maintains an attitude extending horizontally from the protrusion portion 74g to the tip portion 74f.
As a result, the position of the center of gravity G of the entire switching valve body 74 of the large/small flush switching valve device 64 can be adjusted so that the valve body main body 74b in the large flush mode is maintained in an open state.
Therefore, when the large flush mode of the toilet is being executed, it is possible to prevent the valve body main body 74b of the switching valve body 74 of the large/small flush switching valve device 64 from accidentally entering a closed state, thereby ensuring that the large flush of the flush toilet 2 is executed.

Furthermore, according to the flush water tank device 1 of this embodiment, when the toilet's small-flush mode is initiated, the chain-like or linear connecting member (ball chain 78) is pulled up by the pull-up lever 80 of the operating device 32, and the oscillating member 76 is pulled up together with the ball chain 78 from the initial position in which the valve body main body portion 74b of the switching valve body 74 is in the open state.
As a result, the swinging member 76 swings in the direction in which the valve body portion 74b of the switching valve body 74 closes while being connected to the valve body auxiliary portion 74c, and the valve body portion 74b enters the closed state.
Thereafter, when the ball chain 78 is released from its pulled-up state, the oscillating member 76 releases its connection with the valve body auxiliary portion 74c of the switching valve body 74, and is able to oscillate to its initial position while the valve body main body portion 74b is maintained in the closed state (see Figure 11C).
In other words, when the chain-like or linear ball chain 78 is released from its pulled-up state and pulled down, only the oscillating member 76, which has been disconnected from the valve body auxiliary portion 74c of the switching valve body 74, can oscillate to the initial position independently of the valve body main portion 74b and the valve body auxiliary portion 74c.
Furthermore, if the position of the center of gravity G of the entire switching valve body 74 of the large/small flush switching valve device 64 is adjusted so that the valve body main body 74b in the large flush mode is maintained in an open state in order to make the water storage tank body 22 more compact and water-saving, for example, when the small flush mode of the toilet is being executed and the water level difference ΔWL (= WL2 - WL1) between the first water storage section (external area S1 of the small tank 62) and the second water storage section (internal area S2 of the small tank 62) of the water storage tank body 22 becomes small, there is a risk that the downward movement of the chain-like or linear ball chain 78 will cause the valve body main body 78b in the closed state to open.
Therefore, in the flush water tank device 1 of this embodiment, a chain-like or linear ball chain 78 is connected only to the oscillating member 76, which can oscillate independently of the valve body main body 74b and valve body auxiliary part 74c of the switching valve body 74 of the large/small flush switching valve device 64, so that even when the water level difference ΔWL (= WL2 - WL1) between the first water storage section (external area S1 of the small tank 62) and the second water storage section (internal area S2 of the small tank 62) of the water storage tank body 22 is small while the toilet is in the small flush mode, the movement of the chain-like or linear ball chain 78 being pulled down can be prevented from interfering with the valve body main body 74b and valve body auxiliary part 74c, which are maintained in a closed valve state.
This avoids the risk of the downward movement of the chain or linear ball chain 78 causing the valve body main body 74b, which is in a closed state, to open when the toilet is in the small-flush mode, and allows the valve body main body 74b to be maintained in a closed state.
Therefore, while the toilet's small-flush mode is being executed, it is possible to suppress malfunctions in which the valve body main body 74b or the valve body auxiliary part 74c, which are maintained in a closed state, erroneously rotate in the opening direction, causing the valve body main body 74b, which is in a closed state, to switch to an open state, thereby enabling the small-flush mode of the flush toilet 2 to be executed accurately.

Furthermore, with a flush toilet 2 equipped with a flush water tank device 1 according to this embodiment, in large flush mode, the switching valve body 74 of the large/small flush switching valve device 64 can be reliably maintained in an open state, and in small flush mode, the switching valve body 74 of the large/small flush switching valve device 64 can be reliably maintained in a closed state.
Therefore, it is possible to provide a flush toilet 2 equipped with a flush water tank apparatus 1 that can accurately execute both the large and small flush modes of the toilet.

Incidentally, the large/small flush switching valve device 64 of the flush water tank apparatus 1 according to one embodiment of the present invention described above has been described as being applied to a flush water tank apparatus 1 that employs a jet pump unit 42, but it can also be applied to other types of flush water tank apparatus that employ something other than a jet pump unit 42.
In other words, as a form of flush water tank apparatus that employs something other than a jet pump unit 42, a so-called gravity-fed flush water tank apparatus can be adopted in which the water level of flush water stored in the storage tank body is lowered by gravity, discharged from the drain outlet of the storage tank body, and supplied to the toilet body 4, and a large/small flush switching valve device similar to that of this embodiment can be applied to this gravity-fed flush water tank apparatus.

Furthermore, with regard to the large/small flush switching valve device 64 of the flush water tank apparatus 1 according to one embodiment of the present invention described above, a form has been described in which a weight member 74h is provided on the valve body auxiliary portion 74c of the switching valve body 74 as a valve body adjustment portion that adjusts the valve body main body portion 74b to maintain an open state when the large flush mode is switched to, but this is not limited to this form and other forms of valve body adjustment portions may be adopted.
For example, as another form of valve body adjustment portion, a valve body auxiliary portion 74c may be provided on the side parallel to the valve body main portion 74b, centered on the pivot shaft portion 74a, and a member such as a float that makes it easier to generate buoyancy in the direction in which the valve body main portion 74b of the switching valve body 74 is opened, may be provided on the valve body auxiliary portion 74c or the valve body main portion 74b.
Alternatively, a float or the like may be provided as a valve body adjustment portion on the valve body main portion 74b of the switching valve body 74, and a weight member 74h may be provided as a valve body adjustment portion on the valve body auxiliary portion 74c of the switching valve body 74, and valve body adjustment portions may be provided on both the valve body main portion and the valve body auxiliary portion 74c.

1 Flush water tank device 2 Flush toilet 4 Toilet body 6 Bowl section 8 Rim section 10 Shelf section 12 Trap drain channel 12a Trap drain channel inlet 12b Trap drain channel ascent pipe 12c Trap drain channel downcomer pipe 14 Drain 16 Toilet body water conduit 16a First water conduit 16b Second water conduit 18 First rim water outlet 20 Second rim water outlet 22 Water storage tank body 22a Base surface within water storage tank body 22b Lowest bottom surface within jet nozzle housing section of water storage tank body 24 Water supply pipe 26 Constant flow valve 28 Water supply valve device 30 Main valve (water supply valve)
30a: main valve body; 30b: main valve seat; 30c: pressure chamber; 32: operating device (operating portion)
32a Operating lever (operating part)
32b Drive rotation shaft (operation unit)
34 Poppet valve 34a Poppet hole 36 Float 38 Float side pilot valve 38a Float side pilot hole 40 Vacuum breaker valve 42 Jet pump unit 44 Water supply pipe 46 Jet nozzle 48 Flow path switching valve 50 Throat pipe 50a Suction port 50b Discharge port 50c Throat pipe descending pipe 52 Toilet flush flow path 54 Tank water storage flow path 56 Overflow pipe 56a Overflow port 58 Make-up water pipe 60 Large/small flush switching device 62 Small tank for switching between large and small flushes (second water storage section)
64 Large/small flushing switching valve device (large/small flushing switching valve)
66 Small tank partition wall 66a Front partition wall 66b Rear partition wall 68 Small tank main body 68a Bottom surface of small tank main body 68b Switching valve support portion 68c Hinge protrusion (hinge portion)
68d Small communication hole 70 Projection 70a Right side partition wall of the projection (first side wall surface)
70b Left partition wall of protrusion (second side wall surface)
70c: lowest bottom surface of protrusion 72: switching opening 74: switching valve body (large/small flush switching valve)
74a: Rotating shaft portion 74b: Valve body portion 74c: Valve body auxiliary portion 74d: Hinge hole 74e: Base end portion of valve body portion 74f: Tip portion of valve body portion 74g: Protruding portion of valve body portion 74h: Weight member (valve body adjustment portion)
74i Oscillating shaft 76 Oscillating member 78 Ball chain 80 Lifting lever 82 Weight mounting surface 84 Holding portion 84a Base end front and rear holding protrusions 84b Tip end front and rear holding protrusions 84c Holding frame 84d Base end central holding protrusion 86 Hook portion 86a Tip end central holding protrusion 86b Concave curved surface 88 Slit 88a Front slit 88b Rear slit 90 First curved surface 92 Second curved surface A Primary flow path of water supply pipe B Secondary flow path of water supply pipe B0 Rear region with respect to the longitudinal central axis of the water storage tank body C1 Longitudinal central axis that bisects the internal region of the water storage tank body into a front region and a rear region C2 Short central axis that bisects the internal region of the water storage tank body into a left region and a right region C3 A central axis passing through the center of the opening cross section of the switching opening and extending in the left and right longitudinal direction of the water storage tank body C4 A central axis in the longitudinal direction of the throat pipe in a plan view C5 An axis of the hinge d Thickness of the hook portion DWL1 Minimum water level in the water storage tank body when each of the large and small flushes is completed DWL2 Minimum water level in the small tank when the small flush is completed E1 Base end of the hook portion E2 Tip of the hook portion F0 Area in front of the longitudinal central axis of the water storage tank body G Center of gravity of the valve body portion H Jet nozzle accommodating portion L0 Area on the left side of the short-side central axis of the water storage tank body L1 Maximum width dimension in the left and right direction of the flow straightening area in the small tank O1 Center of the drain outlet of the water storage tank body, center of the discharge outlet of the throat pipe O2 Center of the opening cross section of the switching opening P1 Water pressure P2 Water pressure Q Weight mounting portion R0 Area on the right side of the short-side central axis of the water storage tank body R1 R2: Flow straightening area on the main body of the water storage tank R1: Flow straightening area inside the small tank S1: External area of the small tank (first water storage section inside the main body of the water storage tank)
S2: Internal area of small tank (second water storage section in water storage tank body)
T Exterior tank W Cleaning water W1 Maximum width dimension in the front-to-back short direction of the protruding part of the small tank, maximum width dimension in the front-to-back direction of the flow straightening area inside the small tank W2 Maximum width dimension of each when the internal area of the water storage tank body is divided in half in the short direction WL0 Stopping water level, maximum water level WL1 Water level in the water storage tank body (exterior area of the small tank) WL2 Water level in the internal area of the small tank δ Amount of deflection ΔP Water pressure difference ΔWL Water level difference ρ1 First radius of curvature of the first curved surface ρ2 Second radius of curvature of the second curved surface

Claims (8)

A flush water tank device that supplies flush water to a toilet body of a flush toilet, comprising:
a water storage tank body capable of storing flush water for flushing the toilet body;
a large/small flush switching device that allows the amount of flush water supplied from the water storage tank body to the toilet body to be set to either large or small;
and an operation unit that operates the large/small flush switching device when starting toilet flushing, and switches the flushing mode of the toilet to either the large flush mode or the small flush mode,
the water storage tank body includes a drain outlet provided at its bottom to enable flush water in the water storage tank body to be drained toward the toilet body, a first water storage section including the drain outlet, a second water storage section not including the drain outlet, and a partition wall separating the first water storage section from the second water storage section;
The large/small flush switching device includes a switching opening formed to penetrate the partition wall and enabling communication between the first water storage section and the second water storage section of the water storage tank body, and a large/small flush switching valve provided so as to be able to open and close the switching opening,
the partition wall is provided with a switching valve support portion that rotatably supports the large/small flush switching valve at or near the switching opening,
The large/small flush switching valve includes a rotating shaft portion rotatably supported by the switching valve support portion, a valve body main portion provided on the rotating shaft portion to enable opening and closing of the switching opening portion, and a valve body auxiliary portion provided on the side facing or parallel to the valve body main portion around the rotating shaft portion,
at least one of the valve body main body and the valve auxiliary unit is provided with a valve body adjustment unit that adjusts the valve body main body so as to maintain an open state when the operation unit is switched to a large-flush mode,
the valve body main body and the valve body auxiliary portion are configured such that, when the operating portion is switched to the small-flush mode, a closed valve state is maintained due to a water volume difference or a water pressure difference between the flush water stored in each of the first water storage portion and the second water storage portion of the water storage tank body,
A flush water tank apparatus characterized in that the switching valve support portion is provided near the upper portion of the switching opening, and the valve body main body portion is provided so that, when the valve is open, its lower end portion is rotatable from near the bottom surface of the switching opening toward an upward position around the pivot shaft portion . The flush water tank apparatus according to claim 1, wherein the valve body adjustment portion of the large/small flush switching valve is provided on the opposite side to the valve body main body portion centered around the pivot shaft portion, and is provided with a weight member provided on the valve body auxiliary portion. the weight member is plate-shaped, and the valve body assisting portion includes a weight mounting portion to which the weight member is detachably attached,
the weight attachment portion includes a weight attachment surface provided on the tip side of the valve body auxiliary portion, and a holding portion provided on the weight attachment surface and holding the weight member from the side so as to be slidable in the longitudinal direction of the valve body auxiliary portion,
the holding portion includes a hook portion provided on a tip side of the weight mounting surface and elastically deformable in an out-of-plane direction with respect to the weight mounting surface when the weight member is attached or detached,
A flush water tank device as described in claim 2, wherein a concave curved surface is formed on the surface of the hook portion opposite the weight mounting surface so as to partially reduce the thickness between the base end and the tip end of the hook portion. The flush water tank apparatus of claim 3, wherein the base end of the hook portion, in a plan view, is connected to the weight mounting surface adjacent to the base end of the hook portion by curved surfaces of at least two radii of curvature, the curved surfaces including a first curved surface of a first radius of curvature formed on the base end side of the hook portion and a second curved surface of a second radius of curvature formed on the weight mounting surface side adjacent to the base end of the hook portion from the first curved surface, the first radius of curvature being set larger than the second radius of curvature. The pivot shaft portion of the large/small flush switching valve is provided to extend horizontally within the second water storage portion of the water storage tank body, and is provided closer to the first water storage portion of the water storage tank body than the switching opening when viewed from the central axis direction of the switching opening,
The flush water tank apparatus according to any one of claims 1 to 4, wherein the valve body main body comprises a protrusion arranged to protrude in a direction perpendicular to the axial direction of the pivot shaft, and a tip portion arranged in a direction perpendicular to the protruding direction of the protrusion, and the center of gravity of the valve body main body is positioned so that in an open valve state, it maintains an orientation extending horizontally from the protrusion toward the tip portion. The large/small flush switching device further includes a swinging member that is swingably connected to the valve body auxiliary portion of the large/small flush switching valve, and a chain-like or linear connecting member that connects the swinging member to the operating portion and can be pulled up by the operating portion,
When the small-flush mode of the toilet is started and the connecting member is operated to be raised by the operating portion, the swinging member is raised together with the connecting member from an initial position in which the valve body main portion is in an open state, and the valve body main portion can swing in a direction in which the valve body main portion closes while being connected to the valve body auxiliary portion,
A flush water tank apparatus as described in any one of claims 1 to 5, wherein when the connecting member is released from its pulled- up state, the oscillating member is then disconnected from the valve body auxiliary portion and is configured to be able to oscillate to the initial position while the valve body main body portion is maintained in a closed valve state. A flush water tank device that supplies flush water to a toilet body of a flush toilet, comprising:
a water storage tank body capable of storing flush water for flushing the toilet body;
a large/small flush switching device that allows the amount of flush water supplied from the water storage tank body to the toilet body to be set to either large or small;
and an operation unit that operates the large/small flush switching device when starting toilet flushing, and switches the flushing mode of the toilet to either the large flush mode or the small flush mode,
the water storage tank body includes a drain outlet provided at its bottom to enable flush water in the water storage tank body to be drained toward the toilet body, a first water storage section including the drain outlet, a second water storage section not including the drain outlet, and a partition wall separating the first water storage section from the second water storage section;
The large/small flush switching device includes a switching opening formed to penetrate the partition wall and enabling communication between the first water storage section and the second water storage section of the water storage tank body, and a large/small flush switching valve provided so as to be able to open and close the switching opening,
the partition wall is provided with a switching valve support portion that rotatably supports the large/small flush switching valve at or near the switching opening,
The large/small flush switching valve includes a rotating shaft portion rotatably supported by the switching valve support portion, a valve body main portion provided on the rotating shaft portion to enable opening and closing of the switching opening portion, and a valve body auxiliary portion provided on the side facing or parallel to the valve body main portion around the rotating shaft portion,
at least one of the valve body main body and the valve auxiliary unit is provided with a valve body adjustment unit that adjusts the valve body main body so as to maintain an open state when the operation unit is switched to a large-flush mode,
the valve body main body and the valve body auxiliary portion are configured such that, when the operating portion is switched to the small-flush mode, a closed valve state is maintained due to a water volume difference or a water pressure difference between the flush water stored in each of the first water storage portion and the second water storage portion of the water storage tank body,
The pivot shaft portion of the large/small flush switching valve is provided to extend horizontally within the second water storage portion of the water storage tank body, and is provided closer to the first water storage portion of the water storage tank body than the switching opening when viewed from the central axis direction of the switching opening,
The valve body main body comprises a protrusion arranged to protrude in a direction perpendicular to the axial direction of the pivot shaft, and a tip portion arranged in a direction perpendicular to the protruding direction of the protrusion, and the valve body main body is characterized in that its center of gravity is positioned so that in an open valve state it maintains an orientation extending horizontally from the protrusion toward the tip portion . A flush toilet equipped with a flush water tank device according to any one of claims 1 to 7.

Images