JP7615467B2 - Flush toilet - Google Patents

Description

The present invention relates to flush toilets, and in particular to flush toilets that are flushed with flush water supplied from a flush water source to expel waste.

As described in Patent Documents 1 to 3, flush toilets have been known in which a rim water passage is formed inside the rim portion, and flush water guided to a rim spout downstream of the rim water passage is spouted rearward.

Patent Document 1 discloses that a throttle section formed in the upstream water conduit of the rim water conduit increases the flow rate of the wash water and agitates the air that has accumulated downstream of the throttle section. Patent Document 2 discloses that a guide wall section formed in the rim water conduit reduces the air space other than the wash water, thereby reducing the overall volume of the rim water conduit. Patent Document 3 discloses that a step section is formed on the top of the guide wall section in the rim water conduit, creating a turbulent flow in which the wash water rotates even in the space above the step section.

JP 2019-27214 A JP 2019-27138 A JP 2019-49118 A

Thus, in flush toilets such as those described in Patent Documents 1 to 3 above, in order to suppress the generation of abnormal noises caused by air in the flush water when water is discharged from the rim, consideration has been given to passing the flush water through a guide wall section or the like within the rim water passage so as to agitate the air above within the rim water passage.
However, when the flushing water passes through such guide walls within the rim water passage, the pressure loss of the flushing water becomes relatively large, causing the flow rate of the flushing water discharged from the rim water outlet to decrease, resulting in a problem that the cleaning power of the rim water discharged from the bowl portion is reduced.

Therefore, the present invention has been made to solve the problems of the conventional technology described above, and aims to provide a flush toilet that can improve the quietness of the rim water spout and the cleaning performance of the bowl section when spouted from the rim.

In order to achieve the above-mentioned objective, one embodiment of the present invention is a flush toilet that is flushed with flushing water supplied from a flushing water source and discharges waste, comprising a bowl portion having a bowl-shaped waste receiving surface and a rim portion formed on the upper edge of the waste receiving surface, a rim water outlet portion that spouts flushing water from the rim portion into the bowl portion, a rim water passage extending within the rim portion to the rim water outlet portion, and a guide portion provided within the rim water passage, the guide portion being provided at a position opposite to the inlet portion of the rim water passage and formed to rise upward from the bottom surface of the rim water passage, and the guide portion being formed to rise from the bottom surface and comprising a side wall that forms a lateral flow path that passes alongside the guide portion within the rim portion, and a downwardly sloping portion that slopes downward from the upper portion of the guide portion towards the downstream side of the rim water passage.
In one embodiment of the present invention configured in this manner, the guide portion comprises a side wall formed to rise from the bottom surface and forming a flow path that passes through the side of the guide portion within the rim portion, and a downward slope portion that slopes downward from the upper part of the guide portion toward the downstream side of the rim water passage. This allows the guide portion to guide a portion of the flush water upward within the rim water passage, making it easier to remove the air at the upper part of the rim water passage downstream together with the flush water, and flush water that has risen to the upper part of the guide portion is guided downward by the downward slope portion, suppressing pressure loss of flush water that crosses the guide portion, and allowing flush water from the side flow passage that passes through the side of the guide portion to smoothly merge while making it difficult to reduce the flow rate of the flush water guided by the downward slope portion. Therefore, it is possible to reduce the sound generated by the air being discharged as a relatively large mass when the flush water passes through the rim water passage, and to make it difficult to reduce the flow rate of the rim water discharge. This makes it possible to improve the quietness of the rim water discharge of the flush toilet and the flushing performance of the bowl portion by the rim water discharge.

In the present invention, the downwardly inclined portion is preferably formed so that its width narrows toward the downstream side of the rim water passage.
In one embodiment of the present invention configured in this manner, the downwardly sloping portion is formed so that its width narrows toward the downstream side of the rim water passage, thereby increasing the flow rate of the wash water as it passes over the guide portion and is guided downward by the downwardly sloping portion, allowing the wash water to merge smoothly with the wash water from the side flow path that passes along the side of the guide portion and making it easier to guide the flow of the wash water after the two parts are joined.

In the present invention, preferably, the downwardly inclined portion extends to the bottom side region of the rim water passage.
In one embodiment of the present invention configured in this manner, the downwardly inclined portion extends to the bottom area of the rim water passage, whereby flush water that has passed over the guide portion can be guided to the bottom area by the downwardly inclined portion, making it possible to further reduce pressure loss of flush water that passes over the guide portion and to smoothly merge with flush water from the side flow path that passes to the side of the guide portion.

In the present invention, preferably, the downward inclined portion includes a first inclined portion extending from an upper portion of the guide portion, and a second inclined portion extending from the first inclined portion and inclining further downward than the first inclined portion.
In one embodiment of the present invention configured in this manner, the downward inclined portion includes a first inclined portion extending from an upper portion of the guide portion, and a second inclined portion extending from the first inclined portion and inclining further downward than the first inclined portion. This allows a portion of the flush water flowing down along the first inclined portion to flow as if it is jumping out from the first inclined portion into the downstream space, and makes it easier for a flow from a flow path passing by the side of the guide portion to flow below this jumping out flow. This makes it easier for the flow of flush water from the first inclined portion and the flow of flush water from the flow path passing by the side of the guide portion to merge more smoothly.

In the present invention, preferably, the guide portion further includes an upwardly inclined portion provided at a position opposite the inlet portion and inclined upward from the bottom surface towards the downstream side of the rim water passage.
In one embodiment of the present invention configured in this manner, the upwardly sloping portion of the guide section makes it easier for the wash water flowing in from the inlet section to rise to the top of the guide section, making it easier to remove the air at the top of the rim water passage together with the wash water in relatively fine chunks downstream, and suppressing the pressure loss of the wash water rising to the top of the guide section.

In the present invention, the downward inclined portion of the guide portion is preferably longer than the upward inclined portion in a top view.
In one embodiment of the present invention configured as described above, the downward inclined portion of the guide portion is longer than the upward inclined portion in a top view, which suppresses turbulence of the wash water guided by the upward inclined portion, and makes it easier to form a flow in a direction along the downward inclined portion while making it difficult to reduce the flow speed of the wash water guided by the downward inclined portion, making it easier to merge more smoothly with the wash water from the flow path passing by the side of the guide portion.

In the present invention, preferably, the guide portion further includes a flat portion formed on an upper portion thereof.
In one embodiment of the present invention configured in this manner, the guide portion further has a flat portion formed on its upper portion, thereby making it easier for the cleaning water that has risen to the top of the guide portion to flow along the flat portion, preventing the cleaning water from peeling off from the upper portion, and preventing the flow of the cleaning water from being disturbed and causing pressure loss.

In the present invention, the downward inclined portion of the guide portion is preferably formed to have a gentler inclination than the upward inclined portion in a side view.
In one embodiment of the present invention configured as described above, the downward slope portion of the guide portion is formed to have a gentler slope than the upward slope portion in a side view, whereby the wash water rises in a relatively short time due to the relatively steep upward slope portion, suppressing turbulence of the wash water guided by the upward slope portion, and the wash water flows along the downward slope portion for a relatively long time while making it difficult to reduce the flow speed of the wash water guided by the downward slope portion, making it easier to form a flow in a direction along the downward slope portion, and easier to smoothly merge with the wash water from the side flow path passing by the side of the guide portion.

The flush toilet of the present invention can improve the quietness of the rim water spout and the cleaning performance of the bowl section when spouted from the rim.

FIG. 1 is an overall configuration diagram of a flush toilet according to a first embodiment of the present invention. FIG. 1 is a plan view of a flush toilet according to a first embodiment of the present invention. 3 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 2 is a schematic perspective view showing the inside of the rim water passage and guide part of a flush toilet according to a first embodiment of the present invention, with the upper part of the rim part omitted. FIG. 1 is a top view showing the inside of the rim water passage and the guide part as viewed from above, with the upper part of the rim part of a flush toilet according to a first embodiment of the present invention omitted. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. FIG. 13 is a diagram showing an example of the results of a numerical analysis, by computer simulation, of the distribution of flush water and air in the rim water channel of a flush toilet according to the first embodiment of the present invention when flush water is supplied into the rim water channel from an inlet portion. FIG. 11 is a schematic perspective view showing the inside of the rim water passage and guide part with the upper part of the rim part of a flush toilet according to a second embodiment of the present invention omitted. FIG. 3 is a cross-sectional view showing a cross-section along a line similar to line III-III in FIG. 1 in a flush toilet according to a second embodiment of the present invention. FIG. 13 is a top view showing the inside of the rim water passage and the guide portion as viewed from above, with the upper part of the rim portion of a flush toilet according to a second embodiment of the present invention omitted. 11 is a cross-sectional view taken along line XI-XI of FIG.

Next, a flush toilet according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
Fig. 1 is an overall configuration diagram of a flush toilet according to a first embodiment of the present invention. Also, Fig. 2 is a plan view of the flush toilet according to the first embodiment of the present invention, and Fig. 3 is a cross-sectional view taken along line III-III in Fig. 1.
As shown in Figure 1, a flush toilet 1 according to a first embodiment of the present invention comprises a main water supply channel 2 through which flush water supplied from a main water supply source W0 (flush water source) such as a water line passes, a ceramic toilet body 4, and a flush water supply device 6. The flush toilet 1 is flushed with flush water supplied from the main water supply source W0 to expel waste.
In the following explanation of the first embodiment of the present invention, the near side as seen from the user using the flush toilet 1 (the user standing in front of the flush toilet 1 to use the flush toilet 1) is referred to as the front side, the far side as seen from the user is referred to as the rear side, the right side as seen from the front of the flush toilet 1 is referred to as the right side, and the left side as seen from the front is referred to as the left side.

Next, as shown in FIGS. 1 and 2, the toilet body 4 includes a bowl portion 8 for receiving waste, and a drain trap pipe line 12 extending from the bottom of the bowl portion 8.
Furthermore, the flush water supply device 6, which will be described in detail later, is provided rearward of the bowl portion 8 of the toilet body 4, and is a functional part that enables flush water supplied from the main water supply passage 2 to be supplied to the toilet body 4. More specifically, this functional part is powered by electricity, and includes a function for controlling the stop of flush water discharge into the bowl portion 8 of the toilet body 4.

The bowl portion 8 comprises a bowl-shaped waste receiving surface 9, a rim portion 10 formed on the upper edge of the waste receiving surface 9, and a shelf surface 11 provided around the entire circumference to connect the waste receiving surface 9 and the rim portion 10. The shelf surface 11 is formed as a flat surface between the waste receiving surface 9 and the rim portion 10, and forms a slight downward slope inward.

Next, as shown in Figures 2 and 3, the flush toilet 1 further comprises a rim water passage 46 formed in the rim section 10 on either the left or right side of the bowl section 8 so that flush water supplied from the flush water source flows into the bowl section 8, a rim water outlet section 48 formed at the downstream end of the rim water passage 46 and which discharges flush water rearward, and a guide section 50 provided within the rim water passage 46 and which guides the flow of flush water. The rim water passage 46 and the rim water outlet section 48 are formed so that flush water supplied from the flush water source flows into the bowl section 8, forming a swirling flow within the bowl section 8.

The rim water outlet 48 discharges flushing water from the rim 10 into the bowl 8. The rim water outlet 48 is provided at the outlet of the rim water passage 46 in the rim 10 on either the left or right side of the bowl 8 of the toilet body 4 (for example, the right side when looking at the toilet body 4 from the front). The rim water outlet 48 forms the rim water conduit at the opening of the rim 10. The rim water outlet 48 is made of ceramic, but may be made of other materials such as resin. The rim water outlet 48 is provided in the rear area of the toilet body 4, rearward of the center of the toilet body 4 (the central transverse line E extending in the left-right direction so as to divide the bowl 8 in half in the front-rear direction). The rim water outlet 48 is formed as a single rim water outlet on the inner peripheral surface of the rim 10, and is formed to discharge water to the rear of the bowl. The opening direction of the rim spout portion 48 is approximately the same as the extension direction of the inner portion 60.

The bowl portion 8 further includes a rim water outlet passage 68 that extends rearward from the rim water outlet portion 48 on the rear side of the rim water outlet portion 48. The rim water outlet passage 68 is formed in an overhanging shape from the inside to the outside of the bowl portion 8.

1 and 2, a jet water conduit 16 is formed from the outer surface to the bottom of the bowl portion 8 of the toilet body 4. The downstream side of this jet water conduit 16 is directed toward the inlet 12a of the drain trap pipe 12 at the bottom of the bowl portion 8, and a jet water outlet 16a is provided at the downstream end of the jet water conduit 16.
Additionally, a jet-side water supply passage 2b of a flush water supply device 6, the details of which will be described later, is provided upstream of the jet water passage 16 of the toilet body 4. Flush water supplied from this jet-side water supply passage 2b to the jet water passage 16 of the toilet body 4 is discharged from the jet water outlet 16a toward the drain trap pipe 12, so that jet water is discharged.
As shown in FIG. 1, the upstream side of the rim-side water supply passage 2 a of the wash water supply device 6 is connected to a changeover valve 18 (described in detail later) at the branch point B of the main water supply passage 2 .
On the other hand, as shown in FIG. 1, the upstream side of the jet side water supply passage 2b of the cleaning water supply device 6 is connected to a pressure pump 22 (details of which will be described later) of the cleaning water supply device 6, which is provided downstream of the water storage tank 20 of the cleaning water supply device 6.

Next, the drain trap pipe 12 of the toilet body 4 is connected to the bottom of the bowl portion 8 to form a drainage path for discharging waste. The drain trap pipe 12 consists of an inlet 12a provided at the bottom of the bowl portion 8, a trap riser pipe 12b rising from the inlet 12a, and a trap descender pipe 12c descending from the trap riser pipe 12b, with the top 12d being between the trap riser pipe 12b and the trap descender pipe 12c. Also, as shown in FIG. 1, the outlet 12e of the trap descender pipe 12c of the drain trap pipe 12 is connected to the inlet of the drain socket S located at the rear and below the toilet body 4. Furthermore, as shown in FIG. 1, the outlet on the rear side of the drain socket S is connected to the inlet of the drain pipe D extending from the rear wall (not shown) side of the toilet body 4. Water is formed above the connection between the waste receiving surface 9 and the drain trap pipe 12. In this embodiment, the drain trap pipe 12 is shown draining into the drain pipe D on the wall behind the flush toilet 1, but this is not limited to wall drainage, and a drain socket that drains into the floor can be connected and drained into a drain pipe installed on the floor.

Next, each component of the flush water supply device 6 of the flush toilet 1 according to this embodiment will be explained generally with reference to FIG.
First, as shown in FIG. 1, the flush water supply device 6 comprises, from the upstream side to the downstream side of the main water supply passage 2, a stop valve 24, a branch fitting 26, a valve unit 28, and a changeover valve 18.
Next, the valve unit 28 includes a constant flow valve 30, a diaphragm type main valve 32, and an electromagnetic valve 34 such as a solenoid valve.
The flush water supply device 6 also includes a controller 36. The controller 36 has a built-in calculation device such as a CPU and a storage device such as a memory, and can control electrically connected devices based on a predetermined control program, etc. In this embodiment, the controller 36 is configured to function as a control unit that controls the opening and closing operation of the opening/closing valve (solenoid valve 34) of the valve unit 28, the switching operation of the switching valve 18, and the rotation speed and operating time of the pressure pump 22, etc.

Furthermore, the constant flow valve 30 of the valve unit 28 is intended to restrict the flush water that has passed from the stop valve 24 in the main water supply line 2 through the branch fitting 26 to a predetermined flow rate or less.
Incidentally, in a configuration in which a genital sanitary washing device (not shown) is provided for the flush toilet 1, the branch fitting 26 can also be connected to a water supply pipe (not shown) for supplying washing water to the genital sanitary washing device (not shown).
Furthermore, in the valve unit 28, when the solenoid valve 34 is opened under the control of the controller 36, the main valve 32 opens, and the cleaning water that has passed through the main valve 32 from the constant flow valve 30 is supplied to the switching valve 18 at the branch B downstream of the main water supply line 2.
Here, the switching valve 18 is capable of supplying flushing water from the main water supply passage 2 to both the rim side water supply passage 2a and the tank side water supply passage 2c at the same time, making it possible to arbitrarily change the ratio of the amount of water supplied to the rim side and the tank side.

Next, the flush water supply device 6 is equipped with a tank device T that enables flush water supplied from the main water supply passage 2 to be supplied to the toilet body 4. This tank device T is equipped with a water storage tank 20 that is connected to the rear of the toilet body 4 and stores the flush water supplied from the main water supply passage 2, and a pressure pump 22 that pressure-feeds the flush water in this water storage tank 20 to the toilet body 4.
Furthermore, downstream of the branch B on the downstream side of the main water supply passage 2, there are provided a rim side water supply passage 2a that communicates with the rim water passage 46 of the toilet body 4, and a tank side water supply passage 2c that is connected to the water storage tank 20.
As a result, the flush water supplied from the main water supply source W0 to the branch B of the main water supply passage 2 is used as at least one of the rim water supply to the rim side water supply passage 2a and the tank water supply to the tank side water supply passage 2c.

The wash water supply device 6 is also provided with a pump water supply passage 2d extending from the downstream side of the tank side water supply passage 2c to the pressure pump 22, and a jet side water supply passage 2b extending from the pressure pump 22 to the downstream side.
As a result, in the flush toilet 1 of this embodiment, flush water supplied from the main water supply channel 2 under direct water supply pressure is supplied from the rim side water supply channel 2a of the flush water supply device 6 through the rim water passage 46 of the toilet body 4 to the rim water outlet portion 48, making it possible for water to be discharged from the rim water outlet portion 48 (so-called "rim water discharge").
Furthermore, the flush water supplied from the main water supply passage 2 to the flush water supply device 6 passes through the tank side water supply passage 2c, the water storage tank 20, the pump water supply passage 2d and the pressure pump 22 of the flush water supply device 6, and is then supplied from the jet side water supply passage 2b through the jet water conduit 16 of the toilet body 4 to the jet water outlet 16a, making it possible for water to be discharged from the jet water outlet 16a (so-called ``jet water discharge'').
In other words, the flush toilet 1 of this embodiment is capable of using both rim spouting of flush water directly pressurized from the main water supply line 2, and jet spouting of flush water pressurized by the pressure pump 22 from the water storage tank 20, and is configured to function as a so-called hybrid flush toilet 1.

Next, an upper float switch 38 and a lower float switch 40 are respectively disposed inside the water storage tank 20. The water level inside the water storage tank 20 can be detected by these float switches 38, 40.
For example, the upper float switch 38 switches on when the water level in the water tank 20 reaches a predetermined water level, and the controller 36 detects the on state of the upper float switch 38 and closes the solenoid valve 34.
On the other hand, the lower float switch 40 switches on when the water level in the storage tank 20 drops to a predetermined water level that is lower than the predetermined stored water level detected by the upper float switch 38, and the controller 36 detects the on state of the lower float switch 40 and stops the pressure pump 22.
In addition, the pressure pump 22 draws the cleaning water stored in the water tank 20 into the pump water supply passage 2d, and pressurizes the cleaning water from this pump water supply passage 2d into the jet side water supply passage 2b, thereby discharging it from the jet water outlet 16a.

With this structure, during normal toilet flushing, the controller 36 detects the operation of a toilet flush switch (not shown) by the user, and sequentially activates the solenoid valve 34, the switching valve 18, and the pressure pump 22.
This causes water to begin to be discharged sequentially from the rim water outlet 48 and the jet water outlet 16a, and the cleaning water that has cleaned the inside of the bowl portion 8 is discharged from the drain trap pipe 12 together with the waste matter in the bowl portion 8.
Furthermore, after flushing is completed, the controller 36 opens the solenoid valve 34 , the switching valve 18 is switched to the tank side water supply passage 2 c , and the flush water in the main water supply passage 2 is replenished to the water storage tank 20 .
When the water level in the water tank 20 rises and the upper float switch 38 detects the specified water level, the controller 36 closes the solenoid valve 34, causing the main valve 32 to close the main water supply line 2 and stopping the water supply.
Furthermore, each of these devices of the flush water supply device 6 (functional section) is adapted to be stored in a rear functional storage section V0 (see FIG. 2) in the area rearward of the bowl section 8 of the toilet body 4.

Next, the structure of the rim water passage 46 in this embodiment will be specifically described with reference to FIGS.
The rim water passage 46 is provided in the rim portion 10 on either the left or right side of the bowl portion 8 of the toilet body 4 (for example, the right side when the toilet body 4 is viewed from the front side). The rim water passage 46 forms a rim water conduit that extends from an inlet portion 46a located in the rear region of the bowl portion 8 to the rim water outlet portion 48. The rim water passage 46 extends from the rear side of the toilet body 4 toward the front, and then bends toward the rear halfway, forming a so-called U-turn shape. Furthermore, the inlet portion 46a of the rim water passage 46 is connected to the rim side water supply passage 2a of the flush water supply device 6, the details of which will be described later. The flush water supplied from this rim side water supply passage 2a to the rim water passage 46 is discharged from the rim water outlet portion 48 toward the rear into the bowl portion 8 as rim water. The rim water passage 46 is formed of ceramic, but may be formed of other materials such as resin.

The rim water passage 46 has an outer portion 56 that extends forward from the inlet portion 56d inside the rim portion 10, a bent portion 58 that bends inward from the downstream end of the outer portion 56, and an inner portion 60 that extends rearward from the bent portion 58 to the rim water outlet portion 48.

The outer portion 56 extends from the rear region of the toilet body 4 to a front region forward of the central transverse line E of the toilet body 4. The outer portion 56 forms a flow path located outside the inner portion 60. A guide portion 50 is provided within the outer portion 56. The outer wall 46e of the rim water passage 46 forms the outer wall surface of the outer portion 56.

The bent portion 58 forms a return flow path within a limited space in the rim portion on one side of the toilet body 4. The bent portion 58 forms a U-shaped flow path that returns approximately 180 degrees when viewed from above to connect the outer portion 56 and the inner portion 60. The bent portion 58 is formed within the rim portion 10, which extends in a straight line. The bent portion 58 is located in the front region forward of the central transverse line E of the toilet body 4.

As shown in FIG. 3, the inner portion 60 extends from the front region of the toilet body 4 to the rear region rearward of the central transverse line E of the toilet body 4. The inner portion 60 can straighten the flow of flushing water in a straight line just before it reaches the rim spout portion 48.

Next, the structure of the guide portion 50 in this embodiment will be specifically described with reference to FIGS.
The guide portion 50 is formed so as to guide a portion of the flow of flush water into an upper space above the rim water passage 46. The guide portion 50 is provided at a position opposite the inlet portion 46a of the rim water passage 46 and is formed so as to protrude upward from the bottom surface 46b of the rim water passage 46.

The guide section 50 further includes a side wall 52 that is formed to rise from the bottom surface 46b and forms a lateral flow path 53 that passes along the side of the guide section 50 within the rim section 10, a downwardly inclined section 54 that slopes downward from the upper part of the guide section 50 toward the downstream side of the rim water passage 46, an upwardly inclined section 72 that is provided in a position opposite the inlet section 46a and slopes upward from the bottom surface 46b toward the downstream side of the rim water passage 46, and a flat section 74 formed on the upper part of the upwardly inclined section 72.

As shown in FIG. 3, the side wall 52 defines a side flow passage 53 inside the bowl section 8 from the guide section 50 between the side wall 52 and the inner vertical wall 46d of the rim water passage 46. The side flow passage 53 extends along the inside of the toilet bowl of the guide section 50. The side flow passage 53 extends from the inner end on the upstream side of the guide section 50 toward the downstream end on the downstream side of the downward slope section 54. The bottom surface of the side flow passage 53 is formed to be almost flat from the upstream side to the downstream side, which makes it easier to form a relatively fast and rectified flow in the rim water passage 46.

As shown in FIG. 4, the downwardly sloping portion 54 is formed so that its width narrows toward the downstream side of the rim water passage 46. For example, when viewed from above, the downwardly sloping portion 54 is formed so that its width in the left-right direction gradually narrows toward the downstream side of the rim water passage 46.

The lower end of the downwardly sloping portion 54 extends to the bottom side region 70 of the rim water passage 46. The bottom side region 70 is, for example, a region below the bottom surface 46b side of half the height of the rim water passage 46, and is a region in the vicinity of the bottom surface 46b. The bottom side region 70 may be defined in other ways, such as a region below the bottom surface 46b side of half the height of the guide portion 50.

The downward inclined portion 54 is formed so as to gradually decrease in height toward the downstream side of the rim water passage 46. The downward inclined portion 54 includes a first inclined portion 54a extending from the upper portion of the guide portion 50, and a second inclined portion 54b extending from the first inclined portion 54a and inclining further downward than the first inclined portion 54a. Therefore, the second inclined portion 54b on the downstream end side is formed so as to bend further downward from the first inclined portion 54a. The first inclined portion 54a and the second inclined portion 54b are inclined downward toward the downstream side and are also inclined slightly downward toward the side flow path 53 side slightly inside the toilet bowl. The outer portion of the downward inclined portion 54 is connected to the outer wall 46e of the rim water passage 46.

As shown in FIG. 5, the downward inclined portion 54 of the guide portion 50 is longer than the upward inclined portion 72 in a top view. The length L1 connecting the center of the upstream side edge and the center of the downstream side edge of the downward inclined portion 54 is longer than the length L2 connecting the center of the upstream side edge and the center of the downstream side edge of the upward inclined portion 72. In addition, the length L3 of the inner side edge of the downward inclined portion 54 is longer than the length L4 of the inner side edge of the upward inclined portion 72.

As shown in FIG. 6, the downwardly inclined portion 54 of the guide portion 50 is formed to have a gentler inclination than the upwardly inclined portion 72 in a side view. For example, the inclination angle α1 of the downwardly inclined portion 54 with respect to the horizontal is gentler than the inclination angle α2 of the upwardly inclined portion 72 with respect to the horizontal in a side view. The inclination angle α1 of the downwardly inclined portion 54 is the angle between the horizontal and an imaginary line connecting the upper and lower ends of the downwardly inclined portion 54. The inclination angle α1 of the downwardly inclined portion 54 may be determined by the inclination angle of the first inclined portion 54a. The inclination angle α2 of the upwardly inclined portion 72 is the angle between the horizontal and an imaginary line connecting the upper and lower ends of the upwardly inclined portion 72.

The upward inclined portion 72 forms an inclined surface that rises from the bottom surface 46b to the upper part of the guide portion 50. The upward inclined portion 72 is formed in an arc shape that protrudes toward the inlet portion 46a. The upward inclined portion 72 is formed so that the flushing water that flows from the inlet portion 46a toward the upward inclined portion 72 can be easily guided upward. The upward inclined portion 72 is formed so that it gradually becomes higher in the height direction toward the downstream side of the rim water passage 46. The upward inclined portion 72 is formed so that its width in the left-right direction gradually becomes narrower toward the downstream side of the rim water passage 46. The outer portion of the upward inclined portion 72 is connected to the outer wall 46e of the rim water passage 46.

The flat portion 74 forms a substantially horizontal flat surface at the top of the guide portion 50. The flat portion 74 is connected to the downstream end of the upward inclination portion 72. The flat portion 74 is also connected to the upstream end of the downward inclination portion 54. The flat portion 74 is connected to the outer wall 46e of the rim water passage 46. When viewed from above, the flat portion 74 forms a triangular shape together with the upward inclination portion 72. The upward inclination portion 72 and the flat portion 74 are formed continuously, and the flat portion 74 and the downward inclination portion 54 are formed continuously. A part of the upward inclination portion 72 and the downward inclination portion 54 is formed continuously without the flat portion 74. The connection portion between the flat portion 74 and the upward inclination portion 72, and/or the connection portion between the flat portion 74 and the downward inclination portion 54, and/or the connection portion between the upward inclination portion 72 and the downward inclination portion 54 are connected via a step. In addition, the connection between the flat portion 74 and the upwardly inclined portion 72, and/or the connection between the flat portion 74 and the downwardly inclined portion 54, and/or the connection between the upwardly inclined portion 72 and the downwardly inclined portion 54 may be smoothly connected without a step.

Next, the operation (function) of the flush toilet according to the first embodiment of the present invention will be explained with reference to FIGS.
When a user presses, for example, an operation button (not shown) for the large flush after using the toilet, a signal from this operation button (not shown) is sent to the controller 36, commencing the large flush flush operation of the flush toilet 1. When the user operates the operation button (not shown), the controller 36 supplies flush water from a water supply source such as a water line, via the rim-side water supply passage 2a of the flush water supply device 6 to the inlet 46a of the rim water passage 46. The flush water is discharged from the rim-side water supply passage 2a into the rim water passage 46, as shown by arrow W0 (see Figure 5).

As shown in FIG. 5, flush water discharged from the rim-side water supply passage 2a into the rim water passage 46 reaches the guide section 50, which is located opposite the inlet section 46a. A portion of the flush water that reaches the guide section 50 rises toward the upper space in the rim water passage 46 along the upwardly inclined section 72, as shown by the arrow W1. The guide section 50 makes it easier for flush water to flow into the upper space above the center line C2 (see FIG. 6) in the height direction of the rim water passage 46. Therefore, the flush water stirs up the air that has accumulated at the top of the rim water passage 46, making it easier to discharge this air. Therefore, the accumulated air is discharged together with the flush water, which can further suppress the generation of abnormal sounds such as air bursts and air mixing sounds, and can further improve noise reduction.

As shown by arrow W2, the cleaning water that rises to the top of the guide section 50 flows from the upward inclined section 72 along the flat section 74. Since the flat section 74 has a tapered triangular shape at the front side, the cleaning water gradually flows down from the flat section 74 to the downward inclined section 54.

The washing water flowing into the downward inclined portion 54 flows down along the first inclined portion 54a, as shown by the arrow W3. The washing water flows linearly toward the front side along the inclination direction of the first inclined portion 54a. A part of the washing water flows further down from the downstream end of the first inclined portion 54a along the second inclined portion 54b, as shown by the arrow W4 (see FIG. 6). Since the second inclined portion 54b is formed at a steeper inclination angle than the first inclined portion 54a, the washing water is accelerated more on the second inclined portion 54b. On the other hand, a part of the washing water flows from the downstream end of the first inclined portion 54a, as shown by the arrow W5, so as to jump out into the air downstream (forward) without following the second inclined portion 54b.

As shown by arrow W6, a flow is formed on the side of the guide section 50 from the side flow path 53 that passes along the side of the guide section 50. This makes it easier for the flow from the side flow path 53 that passes along the side of the guide section 50 to flow below the flow that shoots out from the downstream end of the first inclined section 54a as shown by arrow W5. This makes it harder for the flow of cleaning water from the first inclined section 54a and the flow of cleaning water from the side flow path 53 that passes along the side of the guide section 50 to collide, making it easier for these flows to merge more smoothly.

As shown by arrow W7, after merging, the cleaning water flows linearly forward through outer portion 56. At this time, the air is stirred in the cleaning water as relatively small chunks, and relatively large chunks of air are less likely to separate at bent portion 58, which suppresses the generation of abnormal noise caused by air.

The cleaning water turns rearward at the bend 58, passes through the inner portion 60, and is discharged rearward from the rim water outlet 48. The cleaning water discharged from the rim water outlet 48 forms a swirling flow that flows downward while swirling inside the bowl portion 8, cleaning the inner wall surface of the bowl portion 8.

Jet water discharge is then started. First, the controller 36 sends a signal to the pressure pump 22 to start it. The flush water stored in the water storage tank 20 is pressurized by the pressure pump 22 and discharged from the jet water discharge port 16a that opens at the bottom of the bowl section 8. The flush water discharged from the jet water discharge port 16a flows into the drain trap pipe 12, and when the drain trap pipe 12 is filled with water, a siphon phenomenon is caused. Due to this siphon phenomenon, the accumulated water and waste in the bowl section 8 are sucked into the drain trap pipe 12 and discharged from the downstream drain pipe (not shown). After a predetermined time has elapsed since flush water was supplied to the toilet body 4, the controller 36 stops the discharge from the rim water discharge port 48 and stops the operation of the pressure pump 22, and the series of flushing operations is completed.

Next, an example of analysis of the operation (action) of the flush toilet according to the first embodiment of the present invention will be described with reference to FIG.
Figure 7 is a diagram showing an example of the results of a numerical analysis, by computer simulation, of the distribution of flush water and air in the rim water channel of a flush toilet according to the first embodiment of the present invention when flush water is supplied from the inlet into the rim water channel. In the numerical analysis results in Figure 7, the white parts indicate areas where flush water is flowing, and the black parts indicate areas where air is present. Figure 7 shows, from top to bottom, the results of the numerical analysis 0.15 seconds, 0.30 seconds, 0.45 seconds, and 0.60 seconds after water supply to the rim water channel 46 begins.

According to the analysis results shown in FIG. 7, the flush water discharged from the rim-side water supply passage 2a into the rim water passage 46 rises along the upward inclination 72 toward the upper space in the rim water passage 46. Therefore, the air accumulated in the upper part of the rim water passage 46 is agitated by the flush water, and this air is gradually discharged as relatively small lumps. The flush water further flows downstream along the flat portion 74. It can be seen that a part of the flush water is easily allowed to flow downstream in the upper space in the rim water passage 46, and the formation of air pockets is suppressed in the regions G and H of the upper space in the rim water passage 46. In addition, the flush water flows down along the downward inclination 54, and smoothly merges with the flush water from the side flow path 53 passing by the side of the guide portion 50 while making it difficult to reduce the flow speed of the flush water guided by the downward inclination 54. Therefore, the turbulence of the flush water flow after the merging is also suppressed, and the occurrence of air pockets in the region H is also suppressed. In this way, the formation of relatively large air pockets, which tend to cause relatively loud noise, is suppressed.

Next, the operation of the flush toilet 1 according to the first embodiment of the present invention described above will be explained.
First, according to the flush toilet 1 according to the first embodiment of the present invention, the guide portion 50 comprises a side wall 52 formed to rise from the bottom surface 46b and forming a side flow path 53 that passes beside the guide portion 50 within the rim portion 10, and a downwardly sloping portion 54 that slopes downward from the top of the guide portion 50 toward the downstream side of the rim water passage 46. This allows the guide portion 50 to guide part of the flush water upward within the rim water passage 46, making it easier to remove air at the top of the rim water passage 46 downstream together with the flush water, and flush water that has risen to the top of the guide portion 50 is guided downward by the downwardly sloping portion 54, suppressing pressure loss of flush water that crosses the guide portion 50, and allowing the flush water to smoothly merge with the flush water from the side flow path 53 that passes beside the guide portion 50, while making it difficult to reduce the flow rate of the flush water guided by the downwardly sloping portion 54. This therefore reduces the sound generated by air being discharged as a relatively large mass when the flush water passes through the rim water passage 46, and makes it difficult to reduce the flow rate of the rim water discharge. This makes it possible to improve the quietness of the rim water spouting of the flush toilet 1 and the cleaning performance of the bowl portion 8 caused by the rim water spouting.

Next, according to the flush toilet 1 according to the first embodiment of the present invention, the downwardly inclined portion 54 is formed so that its width narrows toward the downstream side of the rim water passage 46, so that when flush water that has passed over the guide portion 50 is guided downward by the downwardly inclined portion 54, the flow rate of the flush water is increased, allowing it to smoothly merge with flush water from the side flow path 53 that passes along the side of the guide portion 50, and making it easier to guide the flow of flush water after the merging.

In addition, according to the flush toilet 1 of the first embodiment of the present invention, the downwardly inclined portion 54 extends to the bottom side region 70 of the rim water passage 46. This allows flush water that has passed over the guide portion 50 to be guided to the bottom side region 70 by the downwardly inclined portion 54, further reducing pressure loss of flush water that passes over the guide portion 50 and allowing the flush water to smoothly merge with the flush water from the side flow path 53 that passes along the side of the guide portion 50.

Furthermore, according to the flush toilet 1 according to the first embodiment of the present invention, the downwardly inclined portion 54 includes a first inclined portion 54a extending from the upper portion of the guide portion 50, and a second inclined portion 54b extending from the first inclined portion 54a and inclining further downward than the first inclined portion 54a. This allows a portion of the flush water flowing down along the first inclined portion 54a to flow as if it is jumping out from the first inclined portion 54a into the downstream space, making it easier for the flow from the flow path passing along the side of the guide portion 50 to flow below this jumping out flow. This makes it easier for the flow of flush water from the first inclined portion 54a and the flow of flush water from the flow path passing along the side of the guide portion 50 to merge more smoothly.

Furthermore, according to the flush toilet 1 of the first embodiment of the present invention, the upwardly inclined portion 72 of the guide portion 50 makes it easier for the flush water flowing in from the inlet portion 46a to rise to the top of the guide portion 50, making it easier to remove the air at the top of the rim water passage 46 together with the flush water downstream in relatively fine chunks, and suppressing pressure loss of the flush water rising to the top of the guide portion 50.

Furthermore, according to the flush toilet 1 of the first embodiment of the present invention, the downwardly inclined portion 54 of the guide portion 50 is longer than the upwardly inclined portion 72 when viewed from above. This suppresses turbulence of the flush water guided by the upwardly inclined portion 72, and makes it easier to form a flow in a direction along the downwardly inclined portion 54 while making it difficult for the flow rate of the flush water guided by the downwardly inclined portion 54 to decrease, making it easier for the flush water to merge more smoothly with the flush water from the flow path that passes to the side of the guide portion 50.

Furthermore, according to the flush toilet 1 of the first embodiment of the present invention, the guide portion 50 further includes a flat portion 74 formed on its upper portion, which allows flush water that has risen to the top of the guide portion 50 to easily flow along the flat portion 74, preventing the flush water from peeling off from this upper portion and preventing the flow of flush water from being disturbed, resulting in pressure loss.

Furthermore, according to the flush toilet 1 of the first embodiment of the present invention, the downwardly inclined portion 54 of the guide portion 50 is formed with a gentler incline than the upwardly inclined portion 72 in a side view. As a result, flush water rises in a relatively short time due to the relatively steep upwardly inclined portion 72, suppressing turbulence of the flush water guided by the upwardly inclined portion 72, and while making it difficult for the flow rate of the flush water guided by the downwardly inclined portion 54 to decrease, the flush water flows along the downwardly inclined portion 54 for a relatively long time, making it easier to form a flow in a direction along the downwardly inclined portion 54, and making it easier for the flush water to merge smoothly with the flush water from the side flow path 53 that passes along the side of the guide portion 50.

Next, a flush toilet according to a second embodiment of the present invention will be described with reference to Figures 8 to 11. The second embodiment is an example in which the downwardly sloping portion of the guide section of a flush toilet according to the present invention is formed into a different shape. Figure 8 is a schematic perspective view showing the inside of the rim water passage and the guide section of a flush toilet according to the second embodiment of the present invention, with the upper part of the rim section omitted. Figure 9 is a cross-sectional view showing a cross-section along a line similar to line III-III in Figure 1 in a flush toilet according to the second embodiment of the present invention. Figure 10 is a top view showing the inside of the rim water passage and the guide section as viewed from above, with the upper part of the rim section of a flush toilet according to the second embodiment of the present invention omitted. Figure 11 is a cross-sectional view taken along line XI-XI in Figure 10.
Because the flush toilet 101 according to the second embodiment has a structure roughly similar to the flush toilet 1 according to the first embodiment described above, only the points in which the second embodiment of the present invention differs from the first embodiment will be explained; similar parts will be given the same reference symbols in the drawings and explanations will be omitted.

As shown in FIG. 8, the flush toilet 1 is provided with a guide portion 150 that is provided within the rim water passage 46 and guides the flow of flush water. The guide portion 150 is provided on the outer portion 56 of the rim water passage 46.

Next, the structure of the guide portion 150 in this embodiment will be specifically described with reference to FIGS.
The guide portion 150 is formed so as to guide a portion of the flow of flush water into an upper space above the rim water passage 46. The guide portion 150 is provided at a position opposite the inlet portion 46a of the rim water passage 46 and is formed so as to protrude upward from the bottom surface 46b of the rim water passage 46.

The guide section 150 further includes a side wall 52 that is formed to rise from the bottom surface 46b and forms a side flow path 53 that passes along the side of the guide section 150 within the rim section 10, a downwardly inclined section 154 that slopes downward from the upper part of the guide section 150 toward the downstream side of the rim water passage 46, an upwardly inclined section 72 that is provided in a position opposite the inlet section 46a and slopes upward from the bottom surface 46b toward the downstream side of the rim water passage 46, and a flat section 74 formed on the upper part of the upwardly inclined section 72.

As shown in FIG. 9, the side wall 52 defines a side flow passage 53 inside the bowl section 8 from the guide section 150 between the side wall 52 and the inner vertical wall 46d of the rim water passage 46. The side flow passage 53 extends along the inner side of the toilet bowl of the guide section 150. The side flow passage 53 extends from the inner end on the upstream side of the guide section 150 toward the downstream end on the downstream side of the downward slope section 154.

The downwardly inclined portion 154 is formed so that its width narrows as it approaches the downstream side of the rim water passage 46. For example, when viewed from above, the downwardly inclined portion 154 is formed in a roughly triangular shape, and its width in the left-right direction gradually narrows as it approaches the downstream side of the rim water passage 46.

The lower end of the downwardly sloping portion 154 extends to the bottom side region 70 of the rim water passage 46. The bottom side region 70 is, for example, a region below the bottom surface 46b side of half the height of the rim water passage 46, and is a region in the vicinity of the bottom surface 46b. The bottom side region 70 may be defined in other ways, such as a region below the bottom surface 46b side of half the height of the guide portion 150.

As shown in FIG. 8, the downwardly inclined portion 154 is formed so that it gradually becomes lower in height toward the downstream side of the rim water passage 46. The downwardly inclined portion 154 is formed by an inclined surface with a substantially constant inclination angle from the top of the guide portion 150 to the bottom surface 46b. The downwardly inclined portion 154 is inclined downward toward the downstream side and is also inclined slightly toward the side flow path 53 slightly inside the toilet bowl. The outer portion of the downwardly inclined portion 154 is connected to the outer wall 46e of the rim water passage 46.

As shown in FIG. 10, the downward inclined portion 154 of the guide portion 150 is longer than the upward inclined portion 72 in a top view. The length L11 connecting the center of the upstream side edge and the center of the downstream side edge of the downward inclined portion 154 is longer than the length L12 connecting the center of the upstream side edge and the center of the downstream side edge of the upward inclined portion 72. In addition, the length L13 of the inner side edge of the downward inclined portion 154 is longer than the length L14 of the inner side edge of the upward inclined portion 72.

The downwardly inclined portion 154 of the guide portion 50 is formed to have a gentler inclination than the upwardly inclined portion 72 in a side view. For example, the inclination angle α1 (see FIG. 6) of the downwardly inclined portion 154 with respect to the horizontal is gentler than the inclination angle α2 (see FIG. 6) of the upwardly inclined portion 72 with respect to the horizontal in a side view. The inclination angle α1 of the downwardly inclined portion 154 is the angle between the horizontal and an imaginary line connecting the upper and lower ends of the downwardly inclined portion 154. The inclination angle α2 of the upwardly inclined portion 72 is the angle between the horizontal and an imaginary line connecting the upper and lower ends of the upwardly inclined portion 72.

As shown in FIG. 11, the downward slope 154 forms a relatively large slope from the top of the guide portion 150 to the bottom surface 46b. Therefore, the thickness I1 of the outer wall 46e of the rim water passage 46 near the portion in contact with the downward slope 154 can be made smaller than the conventional thickness in the portion where the downward slope 154 is formed. If the downward slope 154 was not formed as in the conventional case, a platform-shaped protrusion would be formed in the rim water passage up to the portion where the downward slope 154 is not formed, as shown by the dotted line in FIG. 11, and the thickness I2 of the outer wall 46e would be relatively large. In contrast, by forming the downward slope 154, the upper part of the slope is removed, and the thickness I1 of the outer wall 46e where the downward slope 154 is formed can be made smaller, improving the escape of moisture from the ceramic outer wall 46e and reducing the defective rate of the product. In addition, the range of the outer wall 46e having a relatively large thickness can be further reduced, reducing the defective rate of the product. For convenience of explanation, the second embodiment has been described, but the downwardly sloping portion 54 is also formed in the first embodiment, which can similarly reduce the product defect rate.

Again, in this embodiment, the upwardly inclined portion 72 forms an inclined surface that rises from the bottom surface 46b to the top of the guide portion 150. The flat portion 74 forms a substantially horizontal flat surface at the top of the guide portion 150. The flat portion 74 is connected to the upstream end of the downwardly inclined portion 154.

Next, the operation (function) of the flush toilet according to the first embodiment of the present invention will be explained with reference to FIG. 10 etc.
When the large-flush flushing operation of the flush toilet 101 is started, flush water is discharged from the rim-side water supply passage 2a into the rim water passage 46, as shown by arrow W10 (see FIG. 10).

As shown in FIG. 10, flush water discharged from the rim-side water supply passage 2a into the rim water passage 46 reaches the guide section 150, which is located opposite the inlet section 46a. A portion of the flush water that reaches the guide section 150 rises toward the upper space in the rim water passage 46 along the upwardly inclined section 72, as shown by the arrow W11. The guide section 150 makes it easier for flush water to flow into the upper space above the center line C2 (see FIG. 6) in the height direction of the rim water passage 46. Therefore, the air that has accumulated at the top of the rim water passage 46 is quietly agitated by the flush water through relatively small lumps, and this air can be easily discharged quietly through relatively fine air lumps. Therefore, it is possible to further suppress the generation of abnormal noises such as air explosions and air mixing sounds caused by relatively large lumps of accumulated air being discharged all at once together with the flush water, and to further improve quietness.

As shown by arrow W12, the cleaning water that rises to the top of the guide section 150 tends to flow from the upwardly inclined section 72 along the flat section 74, and flows along the flat section 74. Since the flat section 74 has a tapered triangular shape on the front side, the cleaning water gradually flows down from the flat section 74 to the downwardly inclined section 154.

The cleaning water that flows into the downwardly inclined portion 154 flows down along the downwardly inclined portion 154 as shown by the arrow W13. The cleaning water flows linearly toward the front side along the inclination direction of the downwardly inclined portion 154. The cleaning water that flows down along the downwardly inclined portion 154 can flow smoothly down to the vicinity of the bottom surface 46b, and mainly merges with the flow from the side flow path 53 near the bottom surface 46b.

As shown by arrow W14, a flow is formed on the side of the guide section 150 from the side flow path 53 that passes along the side of the guide section 150. The flow of cleaning water from the downward inclined section 154 flows in roughly the same direction as the flow from the side flow path 53, so the flow of cleaning water from the downward inclined section 154 and the flow of cleaning water from the side flow path 53 that passes along the side of the guide section 50 are less likely to collide, making it easier for these flows to merge more smoothly.

As shown by arrow W15, after merging, the cleaning water flows linearly forward through outer portion 56. At this time, air is stirred in the cleaning water, making it difficult for air masses to separate at bent portion 58, and thus reducing the generation of abnormal noise caused by air.

The cleaning water turns rearward at the bend 58, passes through the inner portion 60, and is discharged rearward from the rim water outlet 48. The cleaning water discharged from the rim water outlet 48 forms a swirling flow that flows downward while swirling inside the bowl portion 8, cleaning the inner wall surface of the bowl portion 8.

Next, the operation of the flush toilet 101 according to the second embodiment of the present invention described above will be explained.
In the second embodiment of the present invention configured in this way, the guide portion 150 guides a portion of the flush water upward in the rim water passage 46, making it easier to remove the air at the top of the rim water passage 46 downstream together with the flush water, and the flush water that has risen to the top of the guide portion 150 is guided downward by the downward slope portion 54, suppressing pressure loss of the flush water that exceeds the guide portion 150, and while making it difficult to reduce the flow rate of the flush water guided by the downward slope portion 54, it can smoothly merge with the flush water from the side flow path 53 that passes by the side of the guide portion 150. Therefore, it is possible to reduce the sound generated by the air being discharged as a relatively large mass when the flush water passes through the rim water passage 46, and it is possible to make it difficult to reduce the flow rate of the rim water discharge. This improves the quietness of the rim water discharge of the flush toilet 101 and the flushing performance of the bowl portion 8 by the rim water discharge.

1: Flush toilet 8: Bowl portion 9: Waste receiving surface 10: Rim portion 12a: Inlet portion 46: Rim water passage 46a: Inlet portion 46b: Bottom surface 48: Rim spout portion 50: Guide portion 52: Side wall 53: Side flow path 54: Downward inclined portion 54a: First inclined portion 54b: Second inclined portion 56d: Inlet portion 70: Bottom surface side region 72: Upward inclined portion 74: Flat portion 101: Flush toilet 150: Guide portion 154: Downward inclined portion

Claims (8)

A flush toilet that is flushed with flush water supplied from a flush water source to discharge waste,
A bowl portion including a bowl-shaped waste receiving surface and a rim portion formed on an upper edge of the waste receiving surface;
a rim water outlet portion that discharges flush water from the rim portion into the bowl portion;
A rim water passage extending within the rim portion to the rim spout portion;
A guide portion provided in the rim water passage,
The guide portion is provided at a position opposite to the inlet portion of the rim water passage and is formed so as to protrude upward from the bottom surface of the rim water passage,
The guide portion has a side wall that rises from the bottom surface and defines a side flow path that passes along a side of the guide portion within the rim portion;
a downwardly inclined portion that slopes downward from an upper portion of the guide portion toward the downstream side of the rim water passage. The flush toilet according to claim 1, wherein the downwardly inclined portion is formed so that its width narrows toward the downstream side of the rim water passage. The flush toilet according to claim 1 or 2, wherein the downwardly inclined portion extends to the bottom side area of the rim water passage. The flush toilet according to any one of claims 1 to 3, wherein the downwardly inclined portion comprises a first inclined portion extending from an upper portion of the guide portion, and a second inclined portion extending from the first inclined portion and inclining further downward than the first inclined portion. The flush toilet according to any one of claims 1 to 4, wherein the guide portion further includes an upwardly inclined portion that is provided at a position opposite the inlet portion and that slopes upward from the bottom surface toward the downstream side of the rim water passage. The flush toilet according to claim 5, wherein the downwardly inclined portion of the guide portion is longer than the upwardly inclined portion when viewed from above. The flush toilet according to any one of claims 1 to 6, wherein the guide portion further includes a flat portion formed on its upper portion. The flush toilet according to claim 5, wherein the downwardly inclined portion of the guide portion is formed with a gentler inclination than the upwardly inclined portion when viewed from the side.

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