JP7486307B2 - Flush toilet - Google Patents

Description

This disclosure relates to a flush toilet.

Patent Document 1 discloses a flush toilet equipped with a toilet bowl having a waste receiving surface, a water storage section recessed downward from the lower edge of the waste receiving surface, and a water discharge section that creates a swirling flow within the toilet bowl by discharging flushing water into the toilet bowl. This flush toilet is equipped with a turning section that changes the flow direction of the swirling flow towards the water storage section. When the swirling flow collides with the turning section, a flowing down water flow can be formed that flows down a localized area in the water storage section. By forming a flowing down water flow, this flush toilet enhances the ability to discharge waste within the water storage section.

JP 2012-202143 A

In order to achieve various objectives, such as waste discharge capacity, it is desirable to increase the amount of water flowing down. However, the swirling flow that forms the flowing down water gradually flows down in accordance with the slope of the waste receiving surface in the range from the spout to the turning part. Therefore, there is a limit to how much flow rate the flowing down water can achieve. In relation to these problems, the inventors of the present application have come to recognize that there is room for improvement in the technology of Patent Document 1.

One of the objectives of this disclosure is to provide a flush toilet that can increase the flow rate of the downstream water flow.

One aspect of the present disclosure for solving the above-mentioned problems is a flush toilet. A flush toilet of one aspect is a flush toilet comprising a toilet bowl and a water discharge section, the toilet bowl comprising a waste receiving surface and a water storage section recessed downward from the lower edge of the waste receiving surface, the water discharge section having a water discharge port that opens into the toilet bowl, and by discharging flush water from the water discharge port into the toilet bowl, a first swirling flow and a second swirling flow that merge within the toilet bowl are formed, the second swirling flow travels in a swirling direction in the rear region of the toilet bowl, the toilet bowl comprises a turning section that turns the flow direction of the second swirling flow towards the water storage section by collision with the second swirling flow, and the first swirling flow collides with the second swirling flow in the opposite swirling direction to the turning section so as to push the second swirling flow towards the outer periphery.

1 is a configuration diagram of a toilet device according to an embodiment. 2 is a cross-sectional view taken along line AA of FIG. 1. This is a cross-sectional view taken along line B-B of FIG. FIG. 2 is a plan view showing a portion of the flush toilet of the embodiment. 5 is a diagram showing a part of the CC cross section of FIG. 4. FIG. 5 is a diagram showing a part of the cross section taken along the line DD in FIG. 4. FIG. 5 is a diagram showing a part of the E-E cross section of FIG. 4. FIG. 3 is an enlarged view of FIG. 2 . FIG. 4 is a diagram showing a part of the FF cross section of FIG. 3. FIG. 5 is a diagram showing a part of the cross section taken along the line GG in FIG. 4. 9 is a view showing a part of a toilet device of a modified example, seen from the same perspective as in FIG. 8 . FIG. 8 is an enlarged view of FIG. FIG. 9 is an enlarged view of FIG. FIG. 3 is another enlarged view of FIG. 2 . 1 is a configuration diagram of a water supply device according to an embodiment. This is a cross-sectional view taken along line HH of FIG. FIG. 4 is a cross-sectional plan view showing how cleaning water flows in the initial stage. FIG. 11 is a plan cross-sectional view showing how the wash water flows in a subsequent stage. FIG. 11 is a side cross-sectional view showing how the wash water flows in a subsequent stage. FIG. 11 is a cross-sectional view seen from the rear side showing how cleaning water flows in the initial stage. 11 is a cross-sectional view seen from the rear side showing the flow of cleaning water in a subsequent stage. FIG. FIG. 11 is another cross-sectional plan view showing how cleaning water flows in the initial stage. FIG. 11 is another cross-sectional plan view showing how the wash water flows in a subsequent stage. FIG. 2 is another plan view showing a portion of the flush toilet of the embodiment. 25 is a graph showing the radii of curvature at positions X1 to X9 in FIG. 24 . FIG. 25 is a plan view showing the terminal end of the first water conduit of FIG. 24 .

The following describes the embodiments. Identical components are given the same reference numerals, and duplicate explanations will be omitted. In each drawing, components are omitted, enlarged, or reduced as appropriate for the sake of convenience. The drawings should be viewed according to the orientation of the reference numerals.

Please refer to FIG. 1. FIG. 1 is also a plan view of a flush toilet 10 (hereinafter, simply referred to as the toilet 10). The toilet device 12 of this embodiment mainly comprises the toilet 10 constituting a Western-style toilet, and a water supply device 14 that supplies flush water to the toilet 10. Details of the water supply device 14 will be described later.

Please refer to Figures 2 to 4. The toilet 10 of this embodiment is mainly characterized by the following innovations. These innovations are (1) the upper overhang surface 44 and the lower overhang surfaces 50A, 50B, (2) the overhang portion 28, and (3) two innovations related to the way flushing water flows. First, the configuration that is the premise for these will be explained, and then each will be explained in order.

The material of the toilet 10 in this embodiment is ceramic. The material of the toilet 10 is not particularly limited, and may be, for example, resin. The toilet 10 comprises a toilet bowl 16, an upper surface 18 where the upper end opening of the toilet bowl 16 opens, and a toilet drainage channel 20 connected to the bottom of the toilet bowl 16. The upper surface 18 is provided so as to extend from the upper end opening of the toilet bowl 16 in the front-rear and left-right directions. The toilet drainage channel 20 is connected to a drain pipe (not shown) installed in the building. The toilet drainage channel 20 serves as a passageway for waste and the like to be discharged from inside the toilet bowl 16 into the drainage pipe.

The positional relationships of the components will be described below using three mutually perpendicular directions. These directions are the front-to-rear direction X, the left-to-right direction Y, and the up-to-down direction Z. When the toilet bowl 10 is installed in a toilet room, ideally the front-to-rear direction X and the left-to-right direction Y are horizontal, and the up-to-down direction Z is vertical. The front-to-rear direction X and the left-to-right direction Y correspond to the front-to-rear direction, front-to-rear direction, and left-to-right direction Y of a user sitting in a normal position on a toilet seat (not shown) attached to the toilet bowl 10.

The following description will use the circumferential and radial directions of the toilet bowl 16. The "circumferential direction" refers to the direction going around the center C of the toilet bowl 16 in a plan view, and the "radial direction" refers to the direction perpendicular to the vertical line passing through the center C. The line that bisects the maximum left-right dimension of the toilet 10 is called the left-right center line Ly. Of the isotropic lines Lx1 to Lx3 that divide the maximum front-to-rear dimension of the inner surface of the toilet bowl 16 into four equal parts, the front isotropic line is Lx1, the rear isotropic line is Lx3, and the isotropic line between them is called the front-to-rear center line Lx2. In this embodiment, the center C of the toilet bowl 16 refers to the intersection of the left-to-right center line Ly and the front-to-rear center line Lx2. The outer and inner peripheral sides in the circumferential direction are also simply called the "outer peripheral side" and "inner peripheral side".

With respect to the toilet bowl 16, the area in front of the front isometric line Lx1 is referred to as the front area 16F, the area behind the rear isometric line Lx3 is referred to as the rear area 16B, and the areas between the front isometric line Lx1 and the rear isometric line Lx3 are referred to as the side areas 16R, 16L. The side areas 16R, 16L include a first side area 16R (hereinafter also referred to as the right side area 16R) on one side (the right side in this embodiment) and a second side area 16L (hereinafter also referred to as the left side area 16L) on the other side (the left side in this embodiment).

The toilet bowl 16 comprises a waste receiving surface 22 for receiving waste, a rim portion 24 forming the upper end portion of the toilet bowl 16, and a water collection portion 26 recessed downward from the lower end edge of the waste receiving surface 22. The inner peripheral surface of the rim portion 24 is provided in the range from the upper end opening 16a of the toilet bowl 16 to the outer peripheral end 22a of the waste receiving surface 22.

The rim portion 24 has an overhang portion 28 that protrudes inward from the upper portion of the inner peripheral surface of the rim portion 24. In this embodiment, the overhang portion 28 is provided over a range that covers most of the circumference of the toilet bowl portion 16, more specifically, over the entire circumference. In this embodiment, "over most of the circumference" refers to a range that covers 70% or more of the circumference, preferably 80% or more of the circumference, and more preferably 90% or more of the circumference.

The toilet bowl 10 is equipped with water outlets 30A, 30B that form swirling flows Fa, Fb (see also FIG. 18) by discharging flushing water from water outlets 32A, 32B into the toilet bowl 16. The water outlets 30A, 30B are equipped with water outlets 32A, 32B that open to the inner circumferential surface of the rim 24, and a water passage 33 that supplies flushing water supplied from the water supply device 14 to the water outlets 32A, 32B.

The toilet 10 of this embodiment has multiple water outlets 30A, 30B. The multiple water outlets 30A, 30B include a first water outlet 30A that outlets flushing water from a first water outlet 32A, and a second water outlet 30B that outlets flushing water from a second water outlet 32B. The first water outlet 32A is provided on one side (the right side in this embodiment) of the left-right center line Ly. More specifically, the first water outlet 32A is provided in the right side region 16R. The second water outlet 32B is provided in the rear region 16B of the toilet bowl 16 on the other side (the left side in this embodiment) of the left-right center line Ly. The second water outlet 30B is provided separately from the first water outlet 30A.

The first water discharge section 30A forms a first swirling flow Fa that swirls within the toilet bowl 16 using flush water discharged from the first water discharge port 32A. The second water discharge section 30B forms a second swirling flow Fb that swirls within the toilet bowl 16 using flush water discharged from the second water discharge port 32B.

The toilet bowl 16 includes water conduits 34A, 34B that receive the swirling flows Fa, Fb on a shelf surface 36 and guide them in the swirling direction Dt1, and a turning section 38 that redirects the flow direction of the second swirling flow Fb toward the water reservoir 26. The water conduits 34A, 34B include a first water conduit 34A that guides the first swirling flow Fa in the swirling direction Dt1, and a second water conduit 34B that guides the second swirling flow Fb in the swirling direction Dt1.

See Figures 5 to 8. The shelf surface 36 is provided on the waste receiving surface 22 in a portion of the radial range extending from the outer circumferential end of the waste receiving surface 22 toward the inner circumferential side. In this embodiment, the shelf surface 36 comprises a concave curved surface portion 36a that constitutes the outer circumferential end of the shelf surface 36, and a flat surface portion 36b that is connected to the concave curved surface portion 36a on the inner circumferential side of the concave curved surface portion 36a. The flat surface portion 36b is flat on a cut surface along the radial direction.

The waste receiving surface 22 has a convex curved connecting surface 39 that is connected to the shelf surface 36 on the inner circumferential side of the flat surface portion 36b of the shelf surface 36. The slope of the flat surface portion 36b is gentler than that of the connecting surface 39. Figures 5 to 8 show the boundary B1 between the shelf surface 36 and the connecting surface 39. This boundary B1 is an inflection point between the flat surface portion 36b of the shelf surface 36 and the connecting surface 39 in a cut surface along the radial direction. In this specification, an "inflection point" refers to a point where the curvature changes. This "inflection point" includes, for example, the boundary between a pair of curves with different curvatures, the boundary between a curve and a straight line, etc.

Moving on to the explanation of the first main ingenuity. The toilet bowl 16 has upright surfaces 40, 42A, 42B rising from the outer peripheral end 22a of the waste receiving surface 22. The upright surfaces 40, 42A, 42B include the inner peripheral side upright surface 40 and the rear side upright surfaces 42A, 42B. Each figure shows the boundary B2 between the outer peripheral end 22a of the waste receiving surface 22 and each upright surface 40, 42A, 42B, and the boundary B3 between each upright surface 40, 42A, 42B and the overhang surface 44, 50A, 50B. These boundaries B2, B3 are inflection points in a cut surface along the radial direction. In this specification, the "upright surface" refers to a surface that forms an angle of 45° or more with respect to the horizontal plane in the entire range between the lower inflection points B2 and B4 (described later) and the upper inflection point B3 in a cut surface along the radial direction.

The inner peripheral side standing surface 40 connects the waste receiving surface 22 and the overhang portion 28. The inclination angle of the inner peripheral side standing surface 40 with respect to the horizontal plane is smallest at the front end 24a of the rim portion 24 and increases with increasing distance from the front end 24a in the circumferential direction.

The rim portion 24 has an upper overhang surface 44 provided on the inner peripheral surface of the rim portion 24. The upper overhang surface 44 is provided on the underside of the overhang portion 28. The upper overhang surface 44 extends from the upper end (inflection point B3) of the inner peripheral side standing surface 40 toward the inner peripheral side. In this specification, the "overhang surface" refers to a surface that includes a portion that forms an angle of less than 45° with the horizontal plane in a cut surface along the radial direction. In this embodiment, the upper overhang surface 44 is provided over a range that covers most of the circumferential direction of the toilet bowl portion 16, specifically, over the entire circumference. The upper overhang surface 44 is provided in the front region 16F and the rear region 16B of the toilet bowl portion 16.

In this embodiment, the upper overhang surface 44 is provided with a horizontal upper flat surface 46 that is flat in a cut surface along the radial direction. The upper flat surface 46 is provided over a large portion of the circumferential direction of the toilet bowl 16, more specifically, over the entire circumference. In this specification, "horizontal" includes not only the case where it is parallel to a horizontal plane perpendicular to the vertical line, but also the case where it is inclined with respect to the horizontal plane within a range of more than 0° and 15° or less. The inclination angle of the upper flat surface 46 with respect to the horizontal plane is preferably 0° or more and 10° or less, and more preferably 0° or more and 5° or less. The inclination angle of the lower flat surface 52 described later is the same.

The toilet bowl 16 has openings 48A, 48B that open into the inner peripheral upright surface 40. The openings 48A, 48B include a first opening 48A provided in the right side region 16R of the toilet bowl 16 and a second opening 48B provided in the rear region 16B of the toilet bowl 16. The rear upright surfaces 42A, 42B include a first rear upright surface 42A provided further back than the first opening 48A and a second rear upright surface 42B provided further back than the second opening 48B.

The rim portion 24 has lower overhang surfaces 50A, 50B provided on the inner peripheral surface of the rim portion 24. The lower overhang surfaces 50A, 50B are provided on the outer peripheral side and lower side than the upper overhang surface 44. This condition is satisfied in a cut surface along the radial direction. The lower overhang surfaces 50A, 50B include a first lower overhang surface 50A extending from the upper end (inflection point B3) of the first rear side standing surface 42A toward the inner peripheral side, and a second lower overhang surface 50B extending from the upper end (inflection point B3) of the second rear side standing surface 42A toward the inner peripheral side. The lower overhang surfaces 50A, 50B of this embodiment are provided with a horizontal lower flat surface 52 that is flat in a cut surface along the radial direction.

The lower overhanging surfaces 50A, 50B are provided at positions that vertically face the lower surfaces of the water conduits 34A, 34B. In this embodiment, the lower surfaces of the water conduits 34A, 34B refer to the shelf surface 36. The lower overhanging surfaces 50A, 50B serve as water-conducting surfaces that form the upper surfaces of the water conduits 34A, 34B. The lower overhanging surfaces 50A, 50B come into contact with the swirling flow and thereby have the function of guiding the swirling flow in the swirling direction Dt1.

The rim portion 24 has connection surfaces 54A, 54B that connect the upper overhang surface 44 and the lower overhang surfaces 50A, 50B. At least a portion of the connection surfaces 54A, 54B is configured as part of the inner peripheral side standing surface 40. The connection surfaces 54A, 54B are connected to the upper overhang surface 44 via a concave curved surface portion 56, and are connected to the lower overhang surfaces 50A, 50B via a convex curved surface portion 58. In a cut surface along the radial direction passing through the openings 48A, 48B, the lower inflection point B4, which is the lower end of the inner peripheral side standing surface 40 that is part of the connection surfaces 54A, 54B, is the upper end of the convex curved surface portion 58.

The connection surfaces 54A and 54B include a first connection surface 54A that connects the upper overhang surface 44 and the first lower overhang surface 50A, and a second connection surface 54B that connects the upper overhang surface 44 and the second lower overhang surface 50B. The first connection surface 54A forms the upper edge of the first opening 48A. The vertical dimension of the first connection surface 54A gradually decreases toward the turning direction Dt1 (see FIG. 3). The second connection surface 54B forms the upper edge of the second opening 48B. The second connection surface 54B smoothly continues to a portion of the inner peripheral side standing surface 40 adjacent to both sides of the second connection surface 54B in the circumferential direction. In this specification, "smoothly continuing" means that the two objects being mentioned are continuous without forming unevenness between them.

Each connection surface 54A, 54B extends downward toward the outer periphery. The acute angle θ1 that the second connection surface 54B makes with respect to the horizontal plane is set so that the connection surfaces 54A, 54B are not visible to a user standing in front of the toilet bowl 10 at a distance of 40 cm from the toilet bowl 10. This user is someone of average build in the country where the toilet bowl 10 is sold. This angle θ1 is gentler than the acute angle θ2 that the second rear standing surface 42B makes with respect to the horizontal plane. This condition is met in the entire circumferential range in which the second connection surface 54B is provided.

See Figures 3 and 9. The first lower overhang surface 50A slopes upward in the turning direction Dt1 and smoothly connects to the inner upper surface 32a of the first water outlet 32A and the upper overhang surface 44. The end 50a of the first lower overhang surface 50A on the counter turning direction Dt2 side is located at the same height as the inner upper surface 32a of the first water outlet 32A. The end 50b of the first lower overhang surface 50A on the turning direction Dt1 side is also located at the same height as the upper overhang surface 44. The counter turning direction Dt2 here refers to the side opposite the turning direction Dt1 in the circumferential direction, and the height position refers to the position in the vertical direction Z.

See Figures 9 and 10. The second lower overhang surface 50B smoothly continues to the inner upper surface 32b of the second water outlet 32B. The end 50c of the second lower overhang surface 50B on the counter-rotation direction Dt2 side is located at the same height as the inner upper surface 32b of the second water outlet 32B.

The second water conduit 34B includes a water channel section 35 that guides the swirling flow from the second water outlet 32B to the turning section 38. The water channel section 35 extends linearly in the discharge direction Da of the second water outlet 32B. The discharge direction Da here refers to the direction along the central axis of the second water outlet 32B. The height dimension L0 from the lower surface of the water channel section 35 to the second lower overhang surface 50B is equal in size in the range from the starting end 35a to the ending end 35b of the water channel section 35. The lower surface of the water channel section 35 here refers to the flat surface section 36b of the shelf surface 36 in this embodiment. This condition is met in a vertical cross section cut along the discharge direction Da. In this specification, "equal" includes the case where the two objects to be compared are identical, as well as the case where they are almost identical. The height dimension here refers to the dimension in the vertical direction Z.

The effect of the first ingenuity described above will now be explained. Lower overhang surfaces 50A, 50B and upper overhang surface 44 are provided on the inner peripheral surface of rim portion 24. Therefore, the gap between upper overhang surface 44 and waste receiving surface 22 can be made wider than when upper overhang surface 44 is provided at the same height as lower overhang surfaces 50A, 50B. This makes it easier to insert a cleaning tool (e.g., a cloth) between them from the inner peripheral side, making it easier to clean upper overhang surface 44 and waste receiving surface 22 with the cleaning tool. As a result, good cleanability can be obtained.

The lower overhanging surfaces 50A, 50B form the upper surfaces of the water conduits 34A, 34B. Therefore, the cross-sectional area of the water conduits 34A, 34B can be made smaller than when the lower overhanging surfaces 50A, 50B are provided at the same height as the upper overhanging surface 44. This allows a large amount of swirling flow to flow in the water conduits 34A, 34B. This in turn makes it easier to design a large amount of swirling flow to reach a desired location. The "desired location" here refers to the turning section 38, for example.

The lower overhanging surfaces 50A, 50B are smoothly connected to the inner upper surfaces 32a, 32b of the water outlets 32A, 32B. This allows for a structure with no steps between the inner upper surfaces 32a, 32b of the water outlets 32A, 32B and the lower overhanging surfaces 50A, 50B. As a result, the cleaning water discharged from the water outlets 32A, 32B makes it less likely that areas will be left unwashed.

The first lower overhang surface 50A slopes upward in the turning direction Dt1 and smoothly continues to the upper overhang surface 44. Therefore, compared to when there is a step in the first lower overhang surface 50A on the way to the turning direction Dt1, water traveling along the first lower overhang surface 50A can more easily travel to the upper overhang surface 44. As a result, washing water discharged from the first water outlet 32A makes it less likely that any areas will be left unwashed.

The height dimension L0 (see FIG. 10) is the same from the start end 35a to the end end 35b of the water channel section 35. Therefore, compared to when the height dimension L0 is increased in the swirling direction Dt1, the flush water discharged from the second water outlet 32B is more likely to flow to the turning section 38 while maintaining its momentum. As a result, it is easier to make the high-flow swirling flow reach the turning section 38 and form the high-flow flow Fd (see FIG. 18) described below.

The second connection surface 54B extends downward as it approaches the outer periphery. Therefore, compared to when the second connection surface 54B extends vertically downward from the upper overhang surface 44, the second connection surface 54B can be made less visible when looking inside the toilet bowl 16 from the outside. As a result, good design is achieved. In particular, the second connection surface 54B is provided in the rear region 16B of the toilet bowl 16, which is easily visible to a user standing in front of the toilet 10. This is effective in achieving good design.

Other features of the first ingenuity are described below. Please refer to Figures 2, 3, 5, and 6. The upper overhang surface 44 has a front region 60A provided in an area including the front region 16F of the toilet bowl 16, and a rear region 60B provided in an area including the rear region 16B of the toilet bowl 16. The boundary 62 between the front region 60A and the rear region 60B is provided in the side regions 16R and 16L.

The front region 60A of this embodiment is provided at a constant height. The height dimension of the overhang portion 28 is constant over the entire circumferential range of the front region 60A. The rear region 60B is provided at a lower height than the front region 60A. The height position of the rear region 60B of this embodiment gradually decreases as it approaches the left-right center line Ly of the toilet bowl 16. The height dimension of the overhang portion 28 gradually increases in the rear region 60B as it approaches the left-right center line Ly of the toilet bowl 16.

With the above configuration, the height position Pa1 of the upper overhang surface 44 in the rear region 16B is lower than the height position Pa2 of the upper overhang surface 44 in the front region 16F. This makes it easier to clean a wide circumferential range without the upper overhang surface 44 getting stuck, compared to when there are areas on the upper overhang surface 44 with large height differences.

The rear region 16B of the toilet bowl 16 is an area that is easily visible to a user standing in front of the toilet 10. Therefore, from the perspective of achieving good design, it is desirable to reduce the height dimension of the second connection surface 54B. While achieving this objective, consider a case in which the height position Pa1 of the upper overhang surface 44 of the rear region 16B is aligned with the height position Pa2 of the upper overhang surface 44 of the front region 16F. Figure 11 shows part of a modified toilet device 12 that meets this condition.

In this case, the height position Pb of the second lower overhang surface 50B, which functions as a water guide surface, becomes high, and the water channel cross-sectional area of the second water guide channel 34B becomes large. In this respect, in this embodiment, the height position Pa1 of the upper overhang surface 44 in the rear region 16B is lower than the height position Pa2 of the upper overhang surface 44 in the front region 16F. Therefore, compared to the above-mentioned case, the height dimension of the second connection surface 54B can be reduced while the height position Pb of the second lower overhang surface 50B can be lowered (see Figure 2). As a result, a large flow rate of flush water can be flowed through the second water guide channel 34B while achieving good design.

In addition, consider a case where the height position Pa2 of the upper overhang surface 44 of the front region 16F is aligned with the height position Pa1 of the upper overhang surface 44 of the rear region 16B. According to this embodiment, the gap between the upper overhang surface 44 and the waste receiving surface 22 can be made wider than in such a case. This makes it easier to insert a cleaning tool from the inner periphery between them, and good cleaning performance can be achieved. In other words, a large flow rate of cleaning water can be made to flow through the second water conduit 34B while achieving good design and cleaning performance.

Refer to FIG. 7. In a cut surface along the radial direction passing through the first lower overhang surface 50A and the upper overhang surface 44, the horizontal dimension Ld1 of the first lower overhang surface 50A is greater than the horizontal dimension Lu1 of the upper overhang surface 44. In a similar cut surface, the horizontal dimension of the lower flat surface 52 is greater than the horizontal dimension of the upper flat surface 46. Refer to FIG. 8. In a cut surface along the radial direction passing through the second lower overhang surface 50B and the upper overhang surface 44, the horizontal dimension Ld2 of the first lower overhang surface 50A is greater than the horizontal dimension Lu2 of the upper overhang surface 44. In a similar cut surface, the horizontal dimension of the lower flat surface 52 is greater than the horizontal dimension of the upper flat surface 46.

Here, the horizontal dimensions Ld1 and Ld2 of the lower overhang surfaces 50A and 50B refer to the horizontal dimensions from the inflection point B3 between the rear side standing surface 42B and the lower overhang surfaces 50A and 50B to the inflection point B5 between the lower overhang surfaces 50A and 50B and the convex curved surface portion 58. The inclination angle of the lower overhang surfaces 50A and 50B with respect to the horizontal plane is less than 45° in the range including the inflection point B5. The convex curved surface portion 58 of this embodiment forms a convex curved surface shape with a single radius of curvature that connects the lower overhang surfaces 50A and 50B and a part of the connecting surfaces 54A and 54B (the inner peripheral side standing surface 40). The inclination angle of the convex curved surface portion 58 is 45° or more in a part of the range from the inflection point B5 toward the outer peripheral side. The horizontal dimensions Lu1 and Lu2 of the upper overhang surface 44 refer to the horizontal dimensions from the inflection point B3 between the inner peripheral side standing surface 40 (connection surfaces 54A and 54B) and the upper overhang surface 44 to the inner peripheral end of the overhang portion 28.

This makes it easier to flow a large flow of flushing water through the water conduits 34A and 34B compared to when the horizontal dimensions Lu1 and Lu2 of the upper overhang surface 44 are greater than the horizontal dimensions Ld1 and Ld2 of the lower overhang surfaces 50A and 50B.

Refer to FIG. 7. In a cut surface along the radial direction passing through the first connection surface 54A and the overhang portion 28, the height dimension Ha1 of the first connection surface 54A is greater than the height dimension Hb1 of the overhang portion 28. Here, the height dimension Ha1 of the first connection surface 54A refers to the height dimension from the inflection point B5 to the inflection point B3. Here, the height dimension Hb2 of the overhang portion 28 refers to the height dimension from the inflection point B3 to the upper surface portion 18 of the toilet bowl 10. This condition may be satisfied between the second connection surface 54B and the overhang portion 28.

We now move on to the explanation of the second feature. Please refer to Figures 12 and 13. The underside of the overhanging portion 28, more specifically, the upper overhanging surface 44, is located above the inner upper surfaces 32a, 32b of the water outlets 32A, 32B. The waste receiving surface 22 is located below the inner lower surfaces 32c of the water outlets 32A, 32B at a position Pc where it overlaps with the overhanging portion 28 in the vertical direction Z.

The overhang portion 28 that satisfies these conditions is provided over most of the circumferential range of the toilet bowl 16, specifically, over the entire circumference, with a height dimension La greater than the height dimensions Lb1, Lb2 of the water outlets 32A, 32B from the waste receiving surface 22. This height dimension La refers to the minimum height dimension between the overhang portion 28 and the waste receiving surface 22 on a cross section along the radial direction. In this embodiment, this condition is satisfied in relation to the height dimension Lb1 of the first water outlet 32A, and also in relation to the height dimension Lb2 of the second water outlet 32B.

The overhang portion 28 is composed of a plate-shaped solid portion. This means that no hollow portion is formed in the area that overlaps with the overhang portion 28 in the vertical direction. It can also be said that no hollow portion is formed in the rim portion 24 on the inner side of the inner standing surface 40 (connection surfaces 54A, 54B) in a cut surface along the radial direction. This condition is met over most of the circumferential range of the toilet bowl portion 16, more specifically, over the entire circumference.

The effect of the second ingenuity will be explained. The overhang portion 28 is provided with a height dimension La that is greater than the height dimensions Lb1, Lb2 of the water outlets 32A, 32B relative to the waste receiving surface 22. Therefore, compared to a case where the height dimension La of the overhang portion 28 is set to match the height dimensions Lb1, Lb2 of the water outlets 32A, 32B, it is easier to insert a cleaning tool between the overhang portion 28 and the waste receiving surface 22. As a result, it is easier to clean the overhang portion 28 and the waste receiving surface 22. In particular, by using the overhang portion 28 and the waste receiving surface 22 as guides, it is easier to move a cleaning tool placed between them in a wide circumferential range of the toilet bowl 16. Therefore, it is easier to clean the overhang portion 28 and the waste receiving surface 22 in a wide circumferential range without getting stuck.

The overhang portion 28 is composed of a solid portion. Therefore, the height dimension of the overhang portion 28 can be made smaller than when a hollow portion is formed in the overhang portion 28. As a result, a space of a larger height dimension La can be secured between the overhang portion 28 and the waste receiving surface 22 by the amount of the reduction in the height dimension of the overhang portion 28.

The upper overhang surface 44 of the overhang portion 28 is provided with the upper flat surface 46 described above. Therefore, compared to when the upper overhang surface 44 is greatly inclined with respect to the horizontal plane, a space with a large height dimension La can be secured over a wide radial range between the overhang portion 28 and the waste receiving surface 22.

Other features related to the second ingenuity will be described. See Figures 2, 3, and 5. The waste receiving surface 22 has a central recess 64 provided in the left-right center of the toilet bowl 16, forward of the water storage portion 26. The central recess 64 continues from the lower edge 22b of the waste receiving surface 22 to the outer circumferential end 22a. At least a portion of the central recess 64 is located below the shelf surface 36. The outer circumferential end 64a of the central recess 64 is connected to the inner circumferential upright surface 40 without the shelf surface 36 in between. It can also be understood that the shelf surface 36 is not provided in the left-right center in the front region 16F of the toilet bowl 16.

Refer to Figures 5 and 14. The outer peripheral end 22a of the waste receiving surface 22 is provided with concave curved surface portions 22c, 36a connected to the inner peripheral standing surface 40 as part of the waste receiving surface 22. The concave curved surface portions 22c, 36a include the concave curved surface portion 22c that is part of the central recess 64 and the concave curved surface portion 36a that is part of the shelf surface 36. The concave curved surface portion 22c in this embodiment is a concave curved surface having a single radius of curvature. The inner peripheral standing surface 40 is provided with a flat surface 40a that is flat on a cut surface along the radial direction in the front region 16F of the toilet bowl 16. The flat surface 40a in this embodiment is provided in the range from the lower end to the upper end of the inner peripheral standing surface 40 in the front region 16F of the toilet bowl 16.

The vertical line Lc passing through the inner peripheral end of the overhang portion 28 is set so as to pass through the inner peripheral side standing surface 40, specifically, the flat surface 40a of the inner peripheral side standing surface 40. The vertical line Lc is set so as to pass through the inner peripheral side standing surface 40 on the outer side of the inflection point B2, which is the boundary between the flat surface 40a of the inner peripheral side standing surface 40 and the concave curved surface portion 22c. In this embodiment, this condition is met in at least a part of the front region 16F of the toilet bowl portion 16. More specifically, it is met in a part of the circumferential range including the front end 24a of the rim portion 24.

This allows the overhang portion 28 to protrude less than when the vertical line Lc is set to pass through the waste receiving surface 22. As a result, it becomes easier to reach the back of the underside of the overhang portion 28 with a cleaning tool, resulting in better cleaning performance. This effect is particularly effective in the front region 16F of the toilet bowl 16, which is easily soiled by urine splashes.

See Figures 4, 5, and 14. The left side region 16L is provided on the opposite side of the first water outlet 32A with respect to the left-right center line Ly. The protrusion amount Le1 (hereinafter also referred to simply as the protrusion amount) of the overhang portion 28 in the front region 16F is smaller than the protrusion amount Le2 of the left side region 16L. Here, the protrusion amounts Le1 and Le2 refer to the horizontal dimension from the upper end (inflection point B3) of the inner peripheral side standing surface 40 to the inner peripheral end of the overhang portion 28 on a cut surface along the radial direction.

The amount of protrusion in the left side region 16L and the front region 16F is minimum in the front region 16F and maximum in the left side region 16L. The point where the amount of protrusion in the front region 16F is minimum is the front end 24a of the rim portion 24. The amount of protrusion of the overhang portion 28 in the left side region 16L and the front region 16F gradually increases toward the turning direction Dt1, reaching its maximum, and decreases as it moves away from the maximum point Pd (see Figure 4) in the turning direction Dt1.

This makes it easier for the cleaning tool to reach the back of the area below the overhanging portion 28 in the front region 16F compared to when the protrusion amount Le1 of the overhanging portion 28 in the front region 16F is set to the same as the protrusion amount Le2 in the left side region 16L. As a result, even better cleaning performance can be obtained. This effect is particularly effective in the front region 16F of the toilet bowl 16, which is easily soiled by urine splashes.

In order to explain the third and fourth ingenious points, the premise will be explained. Refer to FIG. 15. The water supply device 14 includes a tank 80 for storing flushing water, an on-off valve 84 installed in an upstream water passage 82 leading to the tank 80, a pump 88 installed in a downstream water passage 86 leading to the tank 80, and a control unit 90 for controlling the on-off valve 84 and the pump 88. The upstream water passage 82 is a passage for flushing water supplied from a water source to the tank 80. The downstream water passage 86 is a passage for flushing water supplied from the tank 80 to the water discharge units 30A and 30B of the toilet 10. The water source is, for example, a water supply system, a water tank, etc. The on-off valve 84 is an electrically driven valve such as a solenoid valve or an electric valve, and can be opened and closed under the control of the control unit 90. The pump 88 can send flushing water in the tank 80 to the toilet 10 under the control of the control unit 90.

When a predetermined cleaning start condition is met, the control unit 90 starts driving the pump 88. This cleaning start condition is, for example, obtaining an operation start command. The operation start command is input to the control unit 90 through the operation of a switch or the like (not shown). When the control unit 90 starts driving the pump 88, it drives the pump 88 at a constant rotation speed until a predetermined set time has elapsed. After the predetermined set time has elapsed, the control unit 90 stops driving the pump 88. Through the above series of operations, a set amount of cleaning water is supplied from the tank 80.

The water supply device 14 is equipped with a float switch (not shown) that detects the water level in the tank 80. When the water level in the tank 80 detected by the float switch falls below the set water level, the control unit 90 switches the on-off valve 84 to the open state. This allows cleaning water to be supplied from the upstream water passage 82 into the tank 80. When the water level in the tank 80 exceeds the set water level, the control unit 90 switches the on-off valve 84 to the closed state. This stops the supply of cleaning water from the upstream water passage 82 into the tank 80. Through the above series of operations, the set amount of cleaning water is stored in the tank 80.

Refer to FIG. 16. The water conduits 34A and 34B are composed of the above-mentioned upright surfaces 40, 42A, and 42B and the overhang surfaces 44, 50A, and 50B in addition to the shelf surface 36. The shelf surface 36 of the first water conduit 34A is formed to extend circumferentially from the first water outlet 32A to the first terminal position Pe1 in the range except for the central recess 64 of the toilet bowl 16. The first terminal position Pe1 is a position that smoothly continues to the shelf surface 36 of the second water conduit 34B on the inner periphery side of the second water outlet 32B. The shelf surface 36 of the second water conduit 34B is formed to extend circumferentially from the second water outlet 32B to the second terminal position Pe2. The second terminal position Pe2 is a position that smoothly continues to the shelf surface 36 of the first water conduit 34A on the inner periphery side of the first water outlet 32A. In this embodiment, the shelf surface 36 is formed over the entire circumferential range of the toilet bowl 16, except for the central recess 64. The shelf surface 36 in this embodiment smoothly continues to the inner lower surface 32c of the spouts 32A and 32B.

See Figures 3 and 16. The water storage section 26 forms the bottom of the toilet bowl 16. Water W that becomes part of the sealing water is stored in the water storage section 26. The water storage section 26 has a bottom wall surface 26a and a number of upright wall surfaces 26b, 26c that rise from the bottom wall surface 26a. The entrance to the toilet drainage channel 20 opens at the rear of the bottom wall surface 26a of the water storage section 26.

The vertical wall surfaces 26b, 26c include a first vertical wall surface 26b provided on one of the left and right sides (the right side in this embodiment) of the water storage section 26, and a second vertical wall surface 26c provided on the other of the left and right sides (the left side in this embodiment) of the water storage section 26. The first vertical wall surface 26b and the second vertical wall surface 26c are tapered toward the front in order to form an induced flow Fe (see FIG. 18) described below, and their front ends are connected via a concave curved surface 26d.

The turning portion 38 is provided on the inner peripheral surface of the rim portion 24. In plan view, the turning portion 38 is formed in the rear region 16B of the toilet bowl portion 16 on the opposite side of the second water outlet 32B with respect to the left-right center line Ly. In plan view, the turning portion 38 is provided at a position that overlaps with the inner peripheral surface of the rim portion 24 when the second water outlet 32B is projected in the discharge direction Da of the second water outlet 32B.

The inner peripheral surface of the rim portion 24 includes a first adjacent portion 94 adjacent to the turning portion 38 in the counter-rotation direction Dt2, and a second adjacent portion 96 adjacent to the turning portion 38 in the rotation direction Dt1. The turning portion 38 is connected to the first adjacent portion 94 via a first bent portion 98 that is concave on the outer peripheral side. The turning portion 38 is connected to the second adjacent portion 96 via a second bent portion 100 that is convex on the inner peripheral side. The first adjacent portion 94 and the turning portion 38 are formed by the second rear side standing surface 42B, and the second adjacent portion 96 is formed by the inner peripheral side standing surface 40. The turning portion 38 and the first adjacent portion 94 are connected to the second lower overhang surface 50B. The second lower overhang surface 50B can suppress the scattering of splashes that occur when colliding with the turning portion 38.

The flushing method using the toilet device 12 described above will now be described with reference to Figures 17 to 19. Figure 17 shows how flush water flows in the initial stage immediately after toilet flushing begins. Figures 18 and 19 show how flush water flows in subsequent stages following the initial stage. In each figure, the main flow direction is indicated with an arrow. In this specification, the "main flow" refers to a streaky flow in which some of the flush water flows in a partially gathered state.

The toilet device 12 of this embodiment discharges waste using a wash-off flushing method that uses a drop in water to flush away waste. When a predetermined flush start condition is met, the water supply device 14 supplies a predetermined set amount of flush water to the water outlets 30A, 30B of the toilet 10. The flush water supplied to the water outlets 30A, 30B is discharged from the water outlets 32A, 32B into the toilet bowl 16 via the water passage 33. The flush water discharged from the water outlets 32A, 32B forms the aforementioned swirling flows Fa, Fb that swirl within the toilet bowl 16. The inside of the toilet bowl 16 is washed by the swirling flows Fa, Fb, and waste within the toilet bowl 16 is discharged through the toilet drainage channel 20.

The first swirling flow Fa passes through the right side region 16R and the front region 16F of the toilet bowl 16, and then travels in a swirling direction through the left side region 16L toward the rear. A portion of the first swirling flow Fa branches off into a branch flow Fc in the front region 16F of the toilet bowl 16. The branch flow Fc flows into the water collection section 26 from the front.

The second swirling flow Fb travels in the swirling direction Dt1 through the rear region 16B of the toilet bowl 16 and forward through the right side region 16R. A portion of the second swirling flow Fb collides with the turning portion 38 and is redirected toward the water storage portion 26. A portion of the second swirling flow Fb is redirected toward the water storage portion 26, forming an inflow water flow Fd that flows into the water storage portion 26 from the rear. The flowing down water flow Fd flows into the water storage portion 26 with greater force than the water flow that gradually flows down from the swirling flows Fa, Fb that are subjected to centrifugal force.

The downflow water flow Fd flows into the water storage section 26 from the rear, dropping down. The downflow water flow Fd flows forward while contacting the first vertical wall surface 26b of the water storage section 26. The forward downflow water flow Fd collides with the bottom wall surface 26a and the first vertical wall surface 26b of the water storage section 26, turning backward and upward within the water storage section 26. As a result, the downflow water flow Fd rises within the water storage section 26 and then descends under its own weight. As a result, the downflow water flow Fd forms a backward induced flow Fe, which is a vertical swirling flow that rotates around an axis in the left-right direction Y. The induced flow Fe descends within the water storage section 26, becoming a flow that pushes waste into the entrance of the toilet drainage channel 20. In this way, the water pool section 26 is configured to form an induced flow Fe that pushes waste into the toilet drainage channel 20 by the downflow water flow Fd that flows forward while contacting the first standing wall surface 26b. The induced flow Fe is joined by a branch flow Fc that flows into the water pool section 26 from the front. This amplifies the water force of the induced flow Fe.

Now, we move on to the explanation of the third ingenuity. Please refer to FIG. 18. The first swirling flow Fa passes through a portion of the one-side half 16c (hereinafter also referred to as the right half 16c) located on one side of the left-right center line Ly of the toilet bowl 16, located in the swirling direction Dt1 from the first water outlet 32A. The second swirling flow Fb passes through a range that straddles the first water outlet 32A in the circumferential direction in the right half 16c of the toilet bowl 16. The first swirling flow Fa and the second swirling flow Fb join together in the toilet bowl 16 when in the subsequent stage. The joining point Pf is on the shelf surface 36 of the first water conduit 34A located in the swirling direction from the first water outlet 32A in the right half 16c of the toilet bowl 16.

Refer to Figure 20. This figure shows a portion of the front region 16F of the toilet bowl 16 from the same perspective as Figure 5. This figure shows the center position Py in the left-right direction Y along the left-right center line Ly. In this figure, a line Lf is drawn on the upper edge of the area where the swirling flow Fa reaches as it flows along the inner circumferential surface of the rim portion 24 at each stage. The same is true for Figure 21.

When the first swirling flow Fa is in the initial stage, it flows upward due to centrifugal force in the front region 16F of the toilet bowl 16, and then flows downward due to its own weight. The first swirling flow Fa travels along the inner circumferential upright surface 40 of the rim portion 24 in the front region 16F of the toilet bowl 16 as a portion 24b of the circumferential range of the inner surface of the rim portion 24. As a result, when the first swirling flow Fa is in the initial stage before merging with the second swirling flow Fb, it travels along the portion 24b of the inner surface of the rim portion 24 to reach the first maximum water level WL1.

The location where the first maximum water level WL1 is reached is a location closer to the swirl direction Dt1 than the front end 24a of the inner circumferential surface of the rim portion 24. In this specification, the "maximum water level" refers to the highest water level in the water flowing along a portion 24b of the inner circumferential surface of the rim portion 24. In the initial stage, the first swirling flow Fa continues to reach the highest water level at a location closer to the swirl direction Dt1 than the front end 24a of the rim portion 24, although there is slight change in position in the vertical and circumferential directions. In this embodiment, the first maximum water level WL1 is above the height position Pc of the inner upper surface 32a of the first water outlet 32A. The first maximum water level WL1 is located below the upper overhang surface 44 of the overhang portion 28.

Refer to FIG. 21. When the first swirling flow Fa is in a subsequent stage after merging with the second swirling flow Fb, the amount of water in the first swirling flow Fa increases by merging with the second swirling flow Fb. As a result, the first swirling flow Fa travels to reach a second maximum water level WL2, which is higher than the first maximum water level WL1, in a portion 24b of the inner circumferential surface of the rim portion 24. The first swirling flow Fa travels to reach a water level in the portion 24b of the rim portion 24 that is higher than when it is in the initial stage.

The point Pg where the second maximum water level WL2 is reached (see also FIG. 4) is a point closer to the swirl direction Dt1 than the front end 24a of the inner surface of the rim portion 24, similar to the point where the first maximum water level WL1 is reached. In the subsequent stage, the first swirling flow Fa is continuously at the highest water level at a point closer to the swirl direction Dt1 than the front end 24a of the rim portion 24, although there is a slight change in position in the vertical and circumferential directions. This second maximum water level WL2 is located above the height position Pc of the inner upper surface 32a of the first water outlet 32A. The second maximum water level WL2 is a position where it reaches the upper overhang surface 44 of the overhang portion 28. The flush water discharged from the second water outlet 32B reaches above the inner upper surface 32a of the first water outlet 32A in the process of running along the inner surface of the rim portion 24. When in the subsequent stage, the water level rises more than when in the initial stage, even at points on both sides of the circumferential direction of the point Pg where the second maximum water level WL2 is reached.

Now, we move on to the explanation of the fourth innovation. See Figure 22. In the initial stage, part of the second swirling flow Fb gradually flows downward in accordance with the gradient of the waste receiving surface 22 as it flows over the waste receiving surface 22. As a result, in the range from the second water outlet 32B to the turning section 38, part Ff of the second swirling flow Fb flows down into the pool section 26 before reaching the turning section 38.

Refer to FIG. 23. In this figure, the first swirling flow Fa and the second swirling flow Fb are shown with hatching. In the subsequent stage, the first swirling flow Fa collides with the second swirling flow Fb in the opposite swirling direction Dt2 from the turning portion 38 of the toilet bowl 16, so as to push the second swirling flow Fb toward the outer periphery. The collision point Ph of the first swirling flow Fa and the second swirling flow Fb is on the shelf surface 36 of the first water conduit 34A in the rear region 16B of the toilet bowl 16. This makes it possible to reduce the amount of water of the second swirling flow Fb that flows down to the pool portion 26 side in the range from the second water outlet 32B to the turning portion 38. As a result, after merging with the first swirling flow Fa, the collision flow rate of the second swirling flow Fb against the turning portion 38 is larger than before merging with the first swirling flow Fa.

The toilet 10 of this embodiment is configured to form the above flows within the toilet bowl 16. In configuring it in this way, the shape of the toilet bowl 16, the flow rate of the flushing water discharged from the water dischargers 30A, 30B, the direction in which the flushing water is discharged, etc. are determined. The flow rate of the flushing water is determined, for example, according to the cross-sectional shape of the water outlets 32A, 32B of the water dischargers 30A, 30B and the water passage 33. In this embodiment, the "shape of the toilet bowl 16" here includes the inner circumferential surface of the rim 24, the waste receiving surface 22, and the water collection section 26.

The effects of the third and fourth improvements will be explained. When the first swirling flow Fa is in a subsequent stage after merging with the second swirling flow Fb, it is transmitted so as to reach a higher water level in the part 24b of the rim portion 24 than when it is in the initial stage. Therefore, compared to when the water level of the first swirling flow Fa in the part 24b of the rim portion 24 does not change, the cleaning range of the inner surface of the rim portion 24 can be made wider in the vertical direction.

In addition, the flow rate of the first swirling flow Fa can be reduced compared to when the first swirling flow Fa reaches the water level in the subsequent stage before merging with the second swirling flow Fb. As a result, splashes are less likely to occur at the junction Pf of the first swirling flow Fa and the second swirling flow Fb.

In particular, the toilet 10 of this embodiment has an overhang portion 28 above the water outlets 32A and 32B, with a height dimension La greater than the water outlets 32A and 32B relative to the waste receiving surface 22. Even in this case, it is effective in widening the cleaning range of the inner surface of the rim portion 24 in the vertical direction.

The second maximum water level WL2 is a position that reaches the overhang portion 28. Therefore, the underside of the overhang portion 28 can also be effectively cleaned by the first swirling flow Fa. In addition, the first maximum water level WL1 is located below the overhang portion 28. Therefore, the flow rate of the first swirling flow Fa can be reduced compared to when the first swirling flow Fa reaches the overhang portion 28 before merging with the second swirling flow Fb. As a result, splashes can be further prevented from occurring at the junction Pf of the first swirling flow Fa and the second swirling flow Fb.

A portion 24b of the rim 24 is provided in the front region 16F of the toilet bowl 16. This is effective in widening the cleaning range in the vertical direction as described above in areas that are easily soiled by urine splashes.

The water discharge sections 30A, 30B include a first water discharge section 30A that forms a first swirling flow Fa and a second water discharge section 30B that forms a second swirling flow Fb. Therefore, compared to using only a single water discharge section 30A, 30B, a large flow rate of swirling flows Fa, Fb can be formed by the wash water discharged from each water discharge section 30A, 30B.

In the case of a direct water supply system in which flushing water is supplied directly from a water source to the toilet bowl 10, the water pressure decreases over time. As a result, the flow rate of flushing water supplied to the toilet bowl 10 decreases over time. In this regard, this embodiment employs a water supply system that uses a pump 88. Therefore, compared to the direct water supply system, a constant flow rate of flushing water can be stably supplied to the toilet bowl 10. This is achieved by driving the pump 88 at a constant rotation speed. This makes it easier to maintain the state in which the second maximum water level WL2 has been reached in the toilet bowl 16 for a long period of time, allowing the inner surface of the rim portion 24 to be cleaned well.

The first swirling flow Fa collides with the second swirling flow Fb in the counter-swirling direction Dt2 from the turning portion 38 of the toilet bowl 16, pushing the second swirling flow Fb toward the outer periphery. This increases the flow rate of the second swirling flow Fb that collides with the turning portion 38. This increases the flow rate of the downflow water flow Fd that is formed by the collision with the turning portion 38. This increases the flow rate of the desired flow to be realized in the reservoir portion 26 by using the high-flow rate downflow water flow Fd that flows into a localized location. In this embodiment, the desired flow here refers to the induced flow Fe described above. This increase in flow rate provides good waste discharge capacity.

Other features of the third ingenuity are described below. See FIG. 18. The second swirling flow Fb merges with the first swirling flow Fa on the right half 16c of the toilet bowl 16. In this embodiment, the following ingenuity is used to ensure that a sufficient flow rate of the second swirling flow Fb can stably reach the junction point Pf.

Refer to Figure 6. In a cross section cut along the left-right direction Y, the horizontal dimension from the center position Py in the left-right direction Y of the toilet bowl 16 to the outer circumferential edge of the waste receiving surface 22 of the right half 16c is called Lg1. In this embodiment, the outer circumferential edge of the waste receiving surface 22 refers to the inflection point B2 between the waste receiving surface 22 and the upright surfaces 40, 42A, and 42B.

In this case, in the same cut surface, the horizontal dimension Lg2 of the shelf surface 36 in the right half 16c is 0.25 times or more larger than the horizontal dimension Lg1. In this specification, the horizontal dimension Lg2 of the shelf surface 36 refers to the horizontal dimension from the inner peripheral end of the shelf surface 36 to the outer peripheral end (in this embodiment, the outer peripheral end of the waste receiving surface 22) in the above-mentioned cut surface. In this embodiment, the inner peripheral end of the shelf surface 36 refers to the inflection point B1 between the flat surface portion 36b of the shelf surface 36 and the connecting surface 39. This numerical condition is satisfied over the entire range in the front-rear direction X at the point where it overlaps with the water storage portion 26 in the left-right direction Y. This numerical condition is set based on the experimental study results of the inventor. This makes it easier to stably deliver a sufficient flow rate of cleaning water to the confluence point Pf of the first swirling flow Fa and the second swirling flow Fb. As a result, the flow described using Figures 20 and 21 can be stably realized.

Other features of the fourth ingenuity point will be described. See Figure 18. The first swirling flow Fa collides with the second swirling flow Fb on the left half 16d of the toilet bowl 16. In this embodiment, the following ingenuity is implemented to ensure that a sufficient flow rate of the first swirling flow Fa reaches the collision point Ph stably.

Refer to FIG. 6. In a cross section cut along the left-right direction, the horizontal dimension from the center position Py in the left-right direction Y of the toilet bowl 16 to the outer periphery of the waste receiving surface 22 of the left half 16d is called Lh1. In this case, in the same cross section, the horizontal dimension Lh2 of the shelf surface 36 in the left half 16d is 0.25 times or more larger than the horizontal dimension Lh1. This numerical condition is satisfied over the entire range in the front-back direction X at the point where it overlaps with the water storage section 26 in the left-right direction Y. This numerical condition is set based on the results of experimental investigations by the inventor. This makes it easier to stably deliver a sufficient flow rate of flushing water to the collision point Ph of the first swirling flow Fa and the second swirling flow Fb. As a result, the flow described using FIG. 22 and FIG. 23 can be stably realized.

Please refer to FIG. 24. The shape of the inner peripheral surface of the rim portion 24 will be described below based on the outer peripheral contour line Li of the rim portion 24 in a plan view. This outer peripheral contour line Li is the outermost edge of the inner peripheral surface of the rim portion 24 in a cut surface cut along the radial direction. In this embodiment, the outer peripheral contour line Li is drawn by the rising surfaces 40, 42A, and 42B of the rim portion 24.

In FIG. 24, dashed lines are drawn at the main positions of inflection points on the outer circumferential contour line Li of the inner circumferential surface of the rim portion 24. In FIG. 25, the radii of curvature at positions X1 to X9 in FIG. 24 are shown. The first water conduit 34A comprises a front portion 34a including the front end portion 16b of the toilet bowl portion 16, a terminal portion 34b provided at the most downstream side of the first water conduit 34A, and an intermediate portion 34c connecting the terminal portion 34b and the front portion 34a. The front portion 34a is concavely curved with a first radius of curvature R1 in a plan view. The first radius of curvature R1 is, for example, 100 to 150 mm. In this embodiment, the front portion 34a has the same radius of curvature over its entire circumferential range.

The inflection point Pj1 between the front portion 34a and the middle portion 34c is provided in the front region 16F of the toilet bowl 16. The inflection point Pj2 between the middle portion 34c and the end portion 34b is provided in the rear region 16B of the toilet bowl 16. In this embodiment, the middle portion 34c includes a first portion 34d that is continuous with the front portion 34a and constitutes the majority of the middle portion 34c, and a second portion 34e that is continuous with the first portion 34d and the end portion 34b. The first portion 34d is concavely curved with a second radius of curvature R2 that is larger than the first radius of curvature R1. The second portion 34e is concavely curved with a third radius of curvature R3 that is smaller than the first radius of curvature R1.

To achieve the flow described using FIG. 23, it is preferable to deliver a sufficient amount of the first swirling flow Fa to the terminal portion 34b of the first water conduit 34A. From this perspective, it is desirable to impart as much centrifugal force as possible to the first swirling flow Fa as it travels from the front end portion 16b of the toilet bowl 16 to the terminal portion 34b of the first water conduit 34A. To impart centrifugal force to the first swirling flow Fa in such a path, it is desirable to make the radius of curvature of the inner peripheral surface of the rim portion 24 in this path in a plan view relatively small. From this perspective, it is preferable to satisfy the following condition.

The maximum radius of curvature of the inner peripheral surface of the water conduits 34A, 34B in the range from the front end 16b of the toilet bowl 16 to the terminal portion 34b of the first water conduit 34A, excluding the terminal portion 34b of the first water conduit 34A, is Rm. In this case, the maximum radius of curvature Rm is preferably 3.5 times or less than the radius of curvature R1, and more preferably 3.0 times or less than the radius of curvature R1. In this embodiment, the maximum radius of curvature Rm is at the first portion 34d of the intermediate portion 34c of the first water conduit 34A. In general, the radius of curvature Rm at the intermediate portion 34c of the first water conduit 34A is 4.0 times or more than the radius of curvature R1.

This allows centrifugal force to be effectively applied to the first swirling flow Fa as it travels from the front end 16b of the toilet bowl 16 to the terminal portion 34b of the first water conduit 34A. As a result, a sufficient flow rate of the first swirling flow Fa can be delivered to the terminal portion 34b of the first water conduit 34A.

Refer to FIG. 26. In this embodiment, the terminal portion 34b of the first water conduit 34A is a concave curved surface having a single radius of curvature. The inner circumferential surface of the rim portion 24 has a third adjacent portion 102 having a convex curved surface adjacent to the terminal portion 34b of the first water conduit 34A in the swirling direction Dt1. The terminal end 34f of the inner circumferential surface of the first water conduit 34A is an inflection point between the concave terminal portion 34b of the first water conduit 34A and the third adjacent portion 102.

Lj is the tangent line that touches the end 34f of the inner peripheral surface of the first water conduit 34A in a plan view. The intersection Pi between the inner peripheral surface of the rear region 16B of the toilet bowl 16 and the tangent line Lj is located on the counter-swirling direction Dt2 side of the left-right center line Ly of the toilet bowl 10. This means that this intersection Pi is located on the second water outlet 32B side of the left-right center line Ly of the toilet bowl 10.

As a result, the flush water discharged from the second water outlet 32B can be held toward the outer periphery sooner than when this intersection Pi is located closer to the turning section 38 (to the right of the paper in FIG. 26) than the left-right center line Ly. As a result, the amount of water in the second swirling flow Fb that flows down toward the pool section 26 can be further reduced in the range from the second water outlet 32B to the turning section 38. As a result, the flow rate of the flowing down water flow Fd that is formed by collision with the turning section 38 can be further increased.

The acute angle that the tangent Lj makes with the left-right center line Ly in a plan view is defined as θ. The smaller this angle θ, the easier it is to hold back the wash water discharged from the second water outlet 32B toward the outer periphery. From this perspective, it is preferable that the angle θ be, for example, 60° or less, and even more preferable that it be 50° or less.

Other variations of each component are described below.

The toilet device 12 may be flushed using a flushing method other than the wash-down method. Such a flushing method may be, for example, a siphon method.

The number of water outlets 30A, 30B is not particularly limited. The number of water outlets 30A, 30B may be either one or three or more. The same applies to the number of water outlets 32A, 32B. An example has been described in which the discharge direction of water outlets 32A, 32B is counterclockwise. Alternatively, the discharge direction of water outlets 32A, 32B may be clockwise. The same applies to the swirling direction Dt1 of the swirling flows Fa, Fb.

An example has been described in which one side in the left-right direction Y is the right side and the other side is the left side. Alternatively, one side in the left-right direction Y may be the left side and the other side may be the right side. This means that the wording "right side" in the embodiment may be replaced with "left side" and the wording "left side" may be replaced with "right side". This assumes, for example, that the swirling direction Dt1 of the swirling flows Fa, Fb is clockwise.

Either the lower overhang surface 50A, 50B or the upper overhang surface 44 may be omitted, or both may be omitted. This means that the overhang portion 28 may be omitted.

The relationship between the height dimension L0 of the overhang portion 28 relative to the waste receiving surface 22 and the height dimensions Lb1, Lb2 of the water outlets 32A, 32B is not particularly limited. For example, the height dimension L0 may be the same as the height dimensions Lb1, Lb2.

The flow of flush water described using Figures 20 and 21 is not essential for the toilet 10. The flow of flush water described using Figures 22 and 23 is not essential for the toilet 10. Of these flow methods, either one of them may be used, or neither of them may be used.

(Regarding the first innovation) The flat surfaces 46, 52 do not have to be provided on each overhang surface 44, 50A, 50B.

The circumferential range in which the upper overhang surface 44 is provided is not particularly limited. For example, the upper overhang surface 44 may be provided only in the front region 16F and the rear region 16B of the toilet bowl 16.

The height position of the upper overhang surface 44 is not particularly limited by the circumferential position of the toilet bowl 16. For example, the upper overhang surface 44 may be provided at a constant height position over the entire circumference of the toilet bowl 16.

The lower overhanging surfaces 50A and 50B do not have to form the upper surfaces of the water channels 34A and 34B. This means that the lower overhanging surfaces 50A and 50B do not have to have the function of guiding wash water.

The lower overhanging surfaces 50A, 50B may be continuous with the inner upper surfaces 32a, 32b of the water outlets 32A, 32B via a stepped surface.

The first lower overhang surface 50A may be continuous with the upper overhang surface 44 via a step surface.

The height dimension H0 from the bottom surface of the water channel portion 35 of the water conduits 34A, 34B to each lower overhang surface 50A, 50B is not particularly limited. This height dimension H0 may be the same size in the turning direction Dt1, while the lower overhang surfaces 50A, 50B may have an upward slope in the turning direction Dt1.

The angle that the connection surfaces 54A, 54B make with respect to the horizontal plane is not particularly limited. The connection surfaces 54A, 54B may extend vertically downward, for example.

(Regarding the second feature) Unlike the embodiment, the overhang portion 28 may have a hollow portion formed therein.

The plumb line Lc passing through the inner circumferential end of the overhang portion 28 may be provided so as to pass through the waste receiving surface 22. The condition that the plumb line Lc is provided so as to pass through the inner circumferential standing surface 40 may be satisfied in any of the side regions 16L, 16R and the rear region 16B of the toilet bowl portion 16.

The amount of protrusion of the overhang portion 28 is not particularly limited. For example, the amount of protrusion Le1 may be the same as the amount of protrusion Le2, or may be greater than the amount of protrusion Le2.

(Regarding the third and fourth ingenuity points) In order to realize the flow of flush water described using Figures 20 and 21, the specific structure of the toilet 10 is not particularly limited. For example, in order to realize this, the toilet 10 may only have the first water discharge section 30A. This assumes the case where the flow of Figure 21 is realized by forming a second swirling flow Fb by a first swirling flow Fa circulating inside the toilet bowl 16, and then merging the second swirling flow Fb with the first swirling flow Fa.

When in the subsequent stage, the first swirling flow Fa may reach a higher water level than when in the initial stage without any change in its maximum water level. This assumes a case where the maximum water level WL1 of the first swirling flow Fa when in the initial stage reaches the overhang portion 28. This also includes cases where, when in the subsequent stage, the water level rises at points on both sides of the circumferential position relative to the point where the maximum water level WL1 is reached when in the initial stage.

The portion 24b of the circumferential range of the inner surface of the rim portion 24 is not particularly limited to the location where the water level changes as shown in FIG. 21. Such a portion 24b of the rim portion 24 may be, for example, the rear region 16B of the toilet bowl portion 16.

The height positions of the first maximum water level WL1 and the second maximum water level WL2 are not particularly limited. For example, the first maximum water level WL1 may be located below the inner upper surface 32a of the first water outlet 32A. In addition, the second maximum water level WL2 may be located below the overhang portion 28.

The horizontal dimensions Lg2, Lh2 of the shelf surface 36 are not particularly limited. The horizontal dimension Lg2 of the shelf surface 36 may be, for example, less than 0.25 times the horizontal dimension Lg1. The horizontal dimension Lh2 of the shelf surface 36 may be, for example, less than 0.25 times the horizontal dimension Lh1.

The water supply method of the water supply device 14 is not particularly limited. The water supply method may be, for example, a direct water supply pressure type. In this case, the water supply device 14 is configured using, for example, a flush valve, etc.

The specific structure of the toilet 10 is not particularly limited in order to realize the flow of flush water described using Figures 22 and 23. For example, to realize this, the toilet 10 may only be equipped with the second water discharge section 30B. This assumes the case where the flow of Figure 23 is realized by forming a first swirling flow Fa by a second swirling flow Fb circulating inside the toilet bowl 16, and then merging the second swirling flow Fb and the first swirling flow Fa.

An example of forming an induction flow Fe in the water storage section 26 using the downflow water flow Fd has been described. The example of the water flow formed in the water storage section 26 using the downflow water flow Fd is not particularly limited. For example, the downflow water flow Fd may flow directly into the entrance of the toilet drainage channel 20.

The radius of curvature of the inner peripheral surface of the first water channel 34A in a plan view is not particularly limited.

The tangent line Li with the inner peripheral surface of the rear region 16B of the toilet bowl 16 and the intersection point Lt may be located closer to the turning portion 38 than the left-right center line Ly.

The above describes the embodiments and the modified examples in detail. When understanding the technical ideas that abstract the embodiments and the modified examples, the technical ideas should not be interpreted as being limited to the contents of the embodiments and the modified examples. The structures referred to in the embodiments and the modified examples naturally include structures that are offset by the amount of errors such as dimensional errors and manufacturing errors. The contents of the embodiments and the modified examples allow for many design changes such as changing, adding, and deleting components. In the above-mentioned embodiments, the contents that allow such design changes are emphasized by adding the notation "embodiment". However, design changes are also allowed even in contents that do not have such notation. The hatching on the cross sections of the drawings does not limit the material of the hatched object. Any combination of the above components is also valid. For example, any description of the modified examples may be combined with the embodiments.

10...flush toilet, 12...toilet bowl device, 14...water supply device, 16...toilet bowl portion, 16B...rear region, 16F...front region, 16b...front end, 22...waste receiving surface, 24...rim portion, 24a...front end, 24b...part, 26...storage portion, 28...overhang portion, 30A, 30B...water outlet portion, 32A, 32B...water outlet, 32a, 32b...inner upper surface, 34A, 34B...water channel, 34b...terminal portion, 34f...terminal end, 36...shelf surface, 38...turning portion, 40...inner circumference side standing surface, 42 A, 42B...rear standing surface, 44...overhang surface, 44...upper overhang surface, 46...upper flat surface, 50A, 50B...lower overhang surface, 54A...connection surface, 80...tank, 88...pump, Fa...first swirling flow, Fb...second swirling flow, Fb...second swirling flow, L0, Lb1, Lb2...height dimension, Le1, Le2...projection amount, Lg1, Lg2, Lh1, Lh2...horizontal dimension, R1, Rm...radius of curvature, WL1...first maximum water level, WL2...second maximum water level.

Claims (4)

A toilet bowl portion,
A flush toilet having a water discharge portion,
The toilet bowl portion includes a waste receiving surface and a water collecting portion recessed downward from a lower end edge of the waste receiving surface,
The water discharge section has a water discharge port that opens into the toilet bowl section, and by discharging flush water from the water discharge port into the toilet bowl section, a first swirling flow and a second swirling flow that merge within the toilet bowl section are formed,
The second swirling flow propagates in a swirling direction through a rear region of the toilet bowl,
The toilet bowl portion is
a water channel that receives the first swirling flow by a shelf surface and guides the first swirling flow in the swirling direction;
a deflection section that deflects the flow direction of the second swirling flow toward the pooling water section by collision of the second swirling flow,
In a plan view, the acute angle θ that a tangent to the end of the inner circumferential surface of the water channel makes with the left-right center line of the flush toilet is 50° or less;
In a cross section taken along the left-right direction, the horizontal dimension of the shelf surface is at least 0.25 times the horizontal dimension from the center of the flush toilet to the outer circumferential edge of the waste receiving surface,
A flush toilet in which the first swirling flow collides with the second swirling flow in a direction opposite to the turning portion so as to push the second swirling flow toward the outer periphery. 2. The flush toilet according to claim 1, wherein, in a plan view, the maximum radius of curvature of the water channel in the range from the front end of the toilet bowl to the terminal portion of the water channel, excluding the terminal portion of the water channel, is 3.5 times or less the radius of curvature of the water channel at the front end of the toilet bowl. 3. The flush toilet according to claim 1 or 2, wherein, in a plan view, the intersection of a tangent to the end of the inner circumferential surface of the water conduit and the inner circumferential surface of the rear region of the toilet bowl is located on the counter-swirling direction side of the left - right center line of the flush toilet. 4. The flush toilet according to claim 1, wherein the water discharge section includes a first water discharge section that forms the first swirling flow by discharging flush water, and a second water discharge section that is provided separately from the first water discharge section and that forms the second swirling flow by discharging flush water.

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