FLUSH TOILET

Abstract

A flush toilet is configured to discharge human waste by flushing with flush water, and includes a bowl and a drain trap pipe line. The bowl includes a waste receiving surface configured to receive human waste, a rim above the waste receiving surface, and a standing water part below the waste receiving surface such that a standing water surface forms inside the standing water part. The drain trap pipe line is connected to a lower part of the bowl and configured to discharge human waste. The rim includes an inner circumferential surface, and one rim discharge port configured to generate a swirling flow by discharging the flush water along the inner circumferential surface. The waste receiving surface includes an upper part having a concave shape extending around an entire circumference of the bowl, and a lower part having a convex shape extending around the entire circumference of the bowl.

Description

TECHNICAL FIELD

Aspects of the present invention relate to a flush toilet, and particularly to a flush toilet that discharges human waste by flushing with flush water.

BACKGROUND

In a known flush toilet such as an example described in Patent Literature 1, one rim discharge port is located at the back left side of a bowl; and the rim discharge port discharges flush water frontward to wash a waste receiving surface with a swirling flow. Such a flush toilet is configured to use the water supply pressure of flush water from a service water pipe to discharge the flush water from the one rim discharge port. The flush water that is discharged from the rim discharge port swirls along an inner circumferential surface of the rim to reach the entire waste receiving surface.

Also, a known flush toilet such as an example described in Patent Literature 2 includes a variable flow rate device that varies the flow rate of the flush water discharged from the rim discharge port. In such a flush toilet, the variable flow rate device varies the flow rate of the flush water discharged from the rim discharge port to wash away human waste adhered to the waste receiving surface. As a result, the flush water evenly reaches the entire waste receiving surface to wash away the human waste adhered to the waste receiving surface.

PRIOR ART

Patent Literature

[Patent Literature 1] Japanese Patent Application Laid-Open No. 2009-052228

[Patent Literature 2] Japanese Patent Application Laid-Open No. 2013-79546

SUMMARY OF THE INVENTION

However, the flush toilet described in the aforementioned Patent Literature 1 has a problem in that if the water supply pressure of the flush water from the service water pipe changes, the flush water cannot evenly reach the entire waste receiving surface; and the human waste that is adhered to the waste receiving surface remains without being washed away. Specifically, if the water supply pressure drops, more flush water is discharged from the rim discharge port and flows downward into the front region of the bowl, and so the flush water no longer reaches the back region of the bowl. Therefore, the human waste that is adhered to the waste receiving surface in the back region of the bowl cannot be washed away sufficiently. On the other hand, if the water supply pressure becomes high, more flush water is discharged from the rim discharge port and swirls toward the back region of the bowl, and so the flush water no longer flows downward onto the waste receiving surface in the front region of the bowl. Therefore, the human waste that is adhered to the waste receiving surface in the front region of the bowl cannot be washed away sufficiently.

FIG. 12 shows flush water swirling around a bowl 102 of a conventional flush toilet 100. In FIG. 12, a flow of the flush water that is discharged from the rim discharge port 100 and flows toward the front region of the bowl 102 is illustrated by F100; and a flow of the flush water that is discharged from the rim discharge port 100 and flows toward the back region of the bowl 102 is illustrated by F101. In FIG. 12, a region that is insufficiently washed by the flush water (a region A) is shown in white.

In the conventional flush toilet 100 as shown in FIG. 12, a portion of the flush water discharged from the rim discharge port 100 flows downward onto the waste receiving surface and flows toward the front region of the bowl 102 (the flow F100 of the flush water). The remainder of the flush water discharged from the rim discharge port 100 swirls around the inner circumferential surface of the rim and flows toward the back region of the bowl 102 (the flow F101 of the flush water). If the water supply pressure is high, the flow rate of the flow F101 of the flush water increases, and the flow rate of the flow F100 of the flush water decreases. Therefore, the waste receiving surface in the front region at the right side of the bowl cannot be sufficiently washed by the flush water (see region A of FIG. 12).

On the other hand, as in the flush toilet described in the aforementioned Patent Literature 2, it may be considered to use a variable flow rate device that varies the flow rate of the flush water discharged from the rim discharge port to suppress the change of the discharge pattern of the flush water discharged from the rim discharge port due to the change of the water supply pressure of the flush water from the service water pipe. However, the use of a variable flow rate device unfavorably increases the product cost.

Therefore, the present invention is directed to solve the problems described above, and is directed to a flush toilet that can cause the flush water to evenly reach the entire waste receiving surface to wash away the human waste adhered to the waste receiving surface while suppressing a product cost increase.

To achieve such an object, an aspect of the present invention is a flush toilet configured to discharge human waste by flushing with flush water, in which the flush toilet includes a bowl and a drain trap pipe line; the bowl includes a waste receiving surface configured to receive human waste, a rim located above the waste receiving surface, and a standing water part that is located below the waste receiving surface and configured so that a standing water surface forms inside the standing water part; the drain trap pipe line is connected to a lower part of the bowl and configured to discharge human waste; the rim includes an inner circumferential surface, and one rim discharge port configured to generate a swirling flow of flush water by discharging the flush water along the inner circumferential surface of the rim; the waste receiving surface includes an upper part and a lower part; the upper part of the waste receiving surface has a concave shape extending around an entire circumference of the bowl; and the lower part of the waste receiving surface has a convex shape extending around the entire circumference of the bowl.

According to the aspect of the present invention having such a configuration, the waste receiving surface includes an upper part and a lower part; the upper part of the waste receiving surface has a concave shape extending around the entire circumference of the bowl; and the lower part of the waste receiving surface has a convex shape extending around the entire circumference of the bowl; therefore, the flush water can be prevented from falling from the upper part of the waste receiving surface; and the flush water can swirl around on the upper part of the waste receiving surface. As a result, the flush water can evenly reach the entire waste receiving surface to wash away the human waste adhered to the waste receiving surface. Also, a product cost increase can be suppressed because a variable flow rate device or the like is not used.

According to the aspect of the present invention, favorably, the rim discharge port is located in a back region of the bowl and configured to discharge the flush water frontward.

In the aspect of the present invention having such a configuration, the rim discharge port is located in the back region of the bowl and configured to discharge the flush water frontward, and so the waste receiving surface in the front region of the bowl can be washed with flush water having a sufficient water force.

According to the aspect of the present invention, favorably, a width of the upper part of the waste receiving surface is greater than a width of the lower part of the waste receiving surface when viewed in plan.

In the aspect of the present invention having such a configuration, the width of the upper part of the waste receiving surface is greater than the width of the lower part of the waste receiving surface when viewed in plan; therefore, the upper part of the waste receiving surface can be increased, and more flush water can swirl around on the upper part of the waste receiving surface.

According to the aspect of the present invention, favorably, a height of the upper part of the waste receiving surface is equal to a height of the lower part of the waste receiving surface or greater than the height of the lower part of the waste receiving surface when viewed in side-view.

In the aspect of the present invention having such a configuration, the height of the upper part of the waste receiving surface is equal to the height of the lower part of the waste receiving surface or greater than the height of the lower part of the waste receiving surface when viewed in side-view; therefore, the upper part of the waste receiving surface can be increased, and more flush water can swirl around on the upper part of the waste receiving surface.

According to the aspect of the present invention, favorably, a boundary between the upper part and the lower part of the waste receiving surface is inclined downward toward a front of the bowl when viewed in side-view.

In the aspect of the present invention having such a configuration, the boundary between the upper part and the lower part of the waste receiving surface is inclined downward toward the front of the bowl when viewed in side-view; therefore, the upper part of the waste receiving surface in the front region of the bowl can be larger, and more flush water can swirl around on the upper part of the waste receiving surface.

According to the aspect of the present invention, favorably, an incline angle of the upper part of the waste receiving surface relative to a horizontal plane is smaller in a front region of the bowl than in the back region of the bowl when viewed in side-view.

In the aspect of the present invention having such a configuration, the incline angle of the upper part of the waste receiving surface relative to the horizontal plane is smaller in the front region of the bowl than in the back region of the bowl when viewed in side-view, and so more flush water can swirl around on the upper part of the waste receiving surface in the front region of the bowl.

According to the aspect of the present invention, favorably, the rim discharge port is located in one of a left region or a right region of the bowl when viewed in plan; and a width of the upper part of the waste receiving surface is larger in the one of the left region or the right region than in the other of the left region or the right region when viewed in plan.

In the aspect of the present invention having such a configuration, the rim discharge port is located in one of the left region or the right region of the bowl when viewed in plan; and the width of the upper part of the waste receiving surface is larger in the one of the left region or the right region than in the other of the left region or the right region when viewed in plan; therefore, the flush water that has been discharged from the rim discharge port and traveled one lap around the bowl can swirl around on the upper part of the waste receiving surface to be guided into the front region of the bowl.

According to flush toilets of aspects of the present invention, flush water can evenly reach the entire waste receiving surface to wash away human waste adhered to the waste receiving surface while suppressing a product cost increase.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a flush toilet according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view along line II-II of FIG. 1;

FIG. 3 is a partially enlarged view of a bowl of the flush toilet according to the embodiment of the present invention shown in FIG. 1;

FIG. 4 is a cross-sectional view along line IV-IV of FIG. 3;

FIG. 5 is a cross-sectional view along line V-V of FIG. 3;

FIG. 6 is a cross-sectional view along line VI-VI of FIG. 3;

FIG. 7 is a cross-sectional view along line VII-VII of FIG. 3;

FIG. 8 is a cross-sectional view along line VIII-VIII of FIG. 3;

FIG. 9 is a cross-sectional view along line IX-IX of FIG. 3;

FIG. 10 is a cross-sectional view along line X-X of FIG. 3;

FIG. 11 is a schematic view showing flush water swirling around the bowl in the flush toilet according to the embodiment of the present invention; and

FIG. 12 is a schematic view showing flush water swirling around a bowl of a conventional flush toilet.

DETAILED DESCRIPTION

A flush toilet according to an embodiment (hereinbelow, referred to as the present embodiment) of the present invention will now be described with reference to the drawings.

First, the overall structure of the flush toilet according to the present embodiment will be described with reference to FIGS. 1 and 2.

FIG. 1 is a plan view of the flush toilet according to the embodiment of the present invention; and FIG. 2 is a cross-sectional view along line II-II of FIG. 1.

As shown in FIGS. 1 and 2, the flush toilet 1 according to the present embodiment is a so-called siphon-jet toilet in which a siphon action is generated by a jet discharge filling the interior of a drain trap pipe line with water. The flush toilet 1 includes a ceramic toilet main body 2, a toilet seat and a toilet lid (not illustrated) located at the upper surface of the toilet main body 2, and a water storage tank (not illustrated) that is located at the upper back part of the toilet main body 2 and stores flush water to be used to flush the toilet.

Flush toilets of embodiments of the present invention are not limited to a siphon-jet flush toilet, and may be a siphon flush toilet that generates a siphon action with rim discharge, or a washdown flush toilet that pushes human waste with a flow action generated by the head of the flush water inside the bowl.

The flush toilet 1 includes the ceramic toilet main body 2; and the toilet main body 2 includes a bowl-shaped bowl 6, a drain trap pipe line 8 that is connected to the lower part of the bowl 6 and discharges human waste, a rim discharge port 10 that performs a rim discharge, a rim water conduit 12 that supplies flush water to the rim discharge port 10, a jet discharge port 14 that performs a jet discharge, and a jet water conduit 16 that supplies flush water to the jet discharge port 14.

The bowl 6 includes a waste receiving surface 18 that receives human waste, a rim 20 that is formed above the bowl 6 and includes an inner circumferential surface 20a at the inner side of the rim 20, a shelf 22 formed between the waste receiving surface 18 and the rim 20, and a standing water part 24 formed below the waste receiving surface 18 and configured so that a standing water surface WL forms inside the standing water part 24.

Although the shelf 22 is included between the waste receiving surface 18 and the rim 20 in the flush toilet 1 of the present embodiment, flush toilets of embodiments of the present invention may not include the shelf 22; and the waste receiving surface 18 and the rim 20 may be directly connected.

The drain trap pipe line 8 includes an inlet 8a, an ascending pipe line 8b extending upward from the inlet 8a, a descending pipe line 8c extending downward from the ascending pipe line 8b, and a top part 8d that is positioned between the descending pipe line 8c and the ascending pipe line 8b and regulates the water level of the standing water surface WL.

The lower end of the descending pipe line 8c of the drain trap pipe line 8 is connected to a drain pipe (not illustrated) via a drain socket (not illustrated).

One rim discharge port 10 is located in a back region at the left side of the bowl 6 and is configured to discharge flush water frontward. The flush water that is discharged from the rim discharge port 10 swirls around the inner circumferential surface 20a of the rim 20 and the shelf 22 while flowing downward onto the waste receiving surface 18; and the waste receiving surface 18 is washed by the swirling flow.

The rim water conduit 12 is formed in a tapered configuration in which the flow channel cross section gradually decreases toward the rim discharge port 10. A service water pipe (not illustrated), which is a water supply source, is connected to the upstream side of the rim water conduit 12. Flush water from the service water pipe is supplied to the rim water conduit 12; and the water supply pressure of the service water pipe is utilized to discharge the flush water from the rim discharge port 10.

The water supply source that supplies the flush water to the rim discharge port 10 is not limited to the service water pipe of the present embodiment and may be a water storage tank, a pump, etc.

The jet discharge port 14 is formed at the bottom part of the bowl 6. The jet discharge port 14 is arranged to face the inlet 8a of the drain trap pipe line 8 and is directed toward the inlet 8a of the drain trap pipe line 8. The jet discharge port 14 discharges the flush water toward the inlet 8a of the drain trap pipe line 8 and generates a siphon action by promptly filling the interior of the drain trap pipe line 8 with water.

The jet water conduit 16 as an entirety is formed in a U-shape when viewed in plan. A water storage tank (not illustrated), which is a water supply source, is connected to the upstream side of the jet water conduit 16. The flush water from the water storage tank is supplied to the jet water conduit 16; and the flush water is discharged from the jet discharge port 14 by the head pressure of the flush water stored inside the water storage tank.

The water supply source that supplies the flush water to the jet discharge port 14 is not limited to the water storage tank of the present embodiment, and may be a service water pipe, a pump, etc.

In the flush toilet 1 of the present embodiment, the flush water amount used in the full flush is 4.8 liters; and the flush water amount used in the light flush is 3.8 liters. The flush water amount that is discharged from the rim discharge port 10 is 2.3 liters; and the instantaneous flow rate of the flush water discharged from the rim discharge port 10 is 10 to 20 L/min.

The shape of the bowl 6 of the flush toilet 1 according to the present embodiment will now be described in detail with reference to FIGS. 3 to 10.

The figures herein are not necessarily drawn to scale, and do not implicitly limit dimensions or proportions of possible features according to various embodiments of the present invention.

FIG. 3 is a partially enlarged view of the bowl of the flush toilet according to the present embodiment shown in FIG. 1; and FIGS. 4 to 10 are cross-sectional views viewed along lines IV-IV to X-X of FIG. 3.

In FIG. 3, regions formed by bisecting the interior of the bowl 6 in the lateral direction as viewed from the front side of the toilet main body by a center line CL1 extending in the longitudinal direction of the toilet main body when viewed in plan are respectively referred to as the left and right regions of the bowl 6. Also, regions formed by bisecting the interior of the bowl 6 in the longitudinal direction by a center line CL2 extending in the lateral direction of the toilet main body when viewed in plan are respectively referred to as the front and back regions of the bowl 6.

“Longitudinal” means “frontward and/or backward”, and “lateral” means “leftward and/or rightward”. “Above”, “below”, “left”, “right”, “front”, “back”, and “behind” each indicate a relative position or action along one respective axis, without implying limitations along other axes. That is, “above” is not implicitly restricted to “directly above”, “behind” is not implicitly restricted to “directly behind”, etc.

As shown in FIGS. 3 to 5, the waste receiving surface 18 is a dry surface that is positioned higher than the standing water surface WL and is exposed to the outside. The waste receiving surface 18 is located between the shelf 22 and the standing water part 24 (the standing water surface WL). The waste receiving surface 18 includes an upper part 18a, which is formed in a downward concave shape extending around the entire circumference of the bowl 6, and a lower part 18b, which is located below the upper part 18a and is formed in an upward convex shape extending around the entire circumference of the bowl 6. As a result, flush water swirls around on the concave-shaped upper part 18a. The upper part 18a of the waste receiving surface 18 is located between the shelf 22 and the lower part 18b; and the lower part 18b of the waste receiving surface 18 is located between the upper part 18a and the standing water part 24 (the standing water surface WL). A boundary X of the upper part 18a and the lower part 18b of the waste receiving surface 18 is set to the position of the inflexion point at which the concave shape changes to the convex shape (see FIGS. 4 and 5).

As shown in FIG. 3, a width W1 of the upper part 18a of the waste receiving surface 18 is set to be greater than a width W2 of the lower part 18b of the waste receiving surface 18 extending around the entire circumference of the bowl 6 when viewed in plan (W1>W2). Herein, the width W1 of the upper part 18a and the width W2 of the lower part 18b are lengths along radial-directions of perfect circles centered on a center O of the bowl 6. As a result, the upper part 18a of the waste receiving surface 18 can be larger, and more flush water can swirl around on the upper part 18a of the waste receiving surface 18.

As shown in FIG. 3, the width W1 of the upper part 18a of the waste receiving surface 18 is set so that a width w1 at the left side in the left region in which the rim discharge port 10 is located is greater than a width w2 at the right side in the right region when viewed in plan (w1>w2). As a result, the flush water that was discharged from the rim discharge port 10 and traveled one lap can be guided over the upper part 18a of the waste receiving surface 18 and into the front region of the bowl 6. Also, the width W1 of the upper part 18a of the waste receiving surface 18 is set so that the width is largest at the front side in the front region of the bowl 6 when viewed in plan; and the width is smallest at the back side in the back region of the bowl 6 when viewed in plan.

As shown in FIGS. 4 to 10, a height H1 of the upper part 18a of the waste receiving surface 18 is set to be equal to a height H2 of the lower part 18b of the waste receiving surface 18 extending around the entire circumference of the bowl 6 or greater than the height H2 of the lower part 18b of the waste receiving surface 18 when viewed in side-view (H1≥H2). As a result, the upper part 18a of the waste receiving surface 18 can be larger; and more flush water can swirl around on the upper part 18a of the waste receiving surface 18. Also, the height H1 of the upper part 18a of the waste receiving surface 18 is set so that the height is largest at the front side in the front region of the bowl 6 when viewed in side-view; and the height is smallest at the back side in the back region of the bowl 6 when viewed in side-view.

As shown in FIGS. 4 and 5, the incline angle of the upper part 18a of the waste receiving surface 18 relative to the horizontal plane (the interior angle between the horizontal plane and the upper part 18a of the waste receiving surface) is smaller in the front region of the bowl 6 than in the back region of the bowl 6 when viewed in side-view. In other words, the incline of the upper part 18a of the waste receiving surface 18 in the front region of the bowl 6 is closer to the horizontal plane than the incline of the upper part 18a of the waste receiving surface 18 in the back region of the bowl 6. As a result, more flush water can swirl around on the upper part 18a of the waste receiving surface 18 in the front region of the bowl 6. As shown in FIGS. 4 and 5, the upper part 18a of the waste receiving surface 18 is set so that the upper part 18a has a first curvature radius R1 in the front region of the bowl 6 and a second curvature radius R2 in the back region of the bowl 6; and the first curvature radius R1 is greater than the second curvature radius R2 (R1>R2).

As shown in FIGS. 4 and 5, the boundary X between the upper part 18a and the lower part 18b of the waste receiving surface 18 is inclined downward toward the front when viewed in side-view. As a result, the upper part 18a of the waste receiving surface 18 in the front region of the bowl 6 can be larger; and more flush water can swirl around on the upper part 18a of the waste receiving surface 18.

The flow of flush water swirling around the bowl 6 in the flush toilet according to the present embodiment will now be described with reference to FIG. 3.

In FIG. 3, a swirling flow of the flush water that is discharged from the rim discharge port 10, swirls around the bowl 6, and travels a first lap is illustrated by F1; and a swirling flow of the flush water that is discharged from the rim discharge port 10, swirls around the bowl 6, and travels a second lap is illustrated by F2.

First, as shown in FIG. 3, the flush water that is discharged from the rim discharge port 10 swirls around on the inner circumferential surface 20a of the rim 20 and the shelf 22 while flowing downward onto the waste receiving surface 18 (the swirling flow F1 of the first lap).

Then, the flush water that was discharged from the rim discharge port 10 and has traveled one lap swirls around on the upper part 18a of the waste receiving surface 18 (the swirling flow F2 of the second lap). The upper part 18a of the waste receiving surface 18 has a concave shape extending around the entire circumference of the bowl 6; therefore, the flush water is prevented from falling from the upper part 18a of the waste receiving surface 18; and the flush water swirls around on the upper part 18a of the waste receiving surface 18.

The flush water that swirled around the upper part 18a of the waste receiving surface 18 flows along the lower part 18b of the waste receiving surface 18 and flows into the standing water surface WL inside the standing water part 24. The flush water that flows into the standing water surface WL flows into the drain trap pipe line 8 and is discharged with the flush water discharged from the jet discharge port 14.

Effects of the flush toilet 1 according to the present embodiment above will now be described.

FIG. 11 is a schematic view showing flush water swirling around the bowl in the flush toilet according to the embodiment of the present invention. In FIG. 11, a flow of the flush water that is discharged from the rim discharge port 10 and flows toward the front region of the bowl 6 is illustrated by F3; and a flow of the flush water that is discharged from the rim discharge port 10 and flows toward the back region of the bowl 6 is illustrated by F4. In FIG. 11, a region that is insufficiently washed by the flush water is shown in white.

In the flush toilet 1 of the present embodiment as shown in FIG. 11, similarly to a conventional flush toilet (see FIG. 12), a portion of the flush water discharged from the rim discharge port 10 flows downward onto the waste receiving surface 18 and flows toward the front region of the bowl 6 (the flow F3 of the flush water). The remainder of the flush water discharged from the rim discharge port 10 swirls around the inner circumferential surface 20a of the rim 20 and the shelf 22 and flows toward the back region of the bowl 6 (the flow F4 of the flush water). In the flush toilet 1 of the present embodiment, the upper part 18a of the waste receiving surface 18 has a concave shape extending around the entire circumference of the bowl 6, and so the flush water that has traveled one lap around the bowl 6 swirls around on the upper part 18a of the waste receiving surface 18 (the flow F4 of the flush water). As a result, the flush water can reach the front region at the right side of the bowl 6 to reduce the region insufficiently washed by the flush water (the white portion of FIG. 11) compared to the conventional flush toilet (see FIG. 12).

In the flush toilet 1 according to the present embodiment, the waste receiving surface 18 includes the upper part 18a and the lower part 18b; the upper part 18a of the waste receiving surface 18 has a concave shape extending around the entire circumference of the bowl 6; and the lower part 18b of the waste receiving surface 18 has a convex shape extending around the entire circumference of the bowl 6; therefore, the flush water can be prevented from falling from the upper part 18a of the waste receiving surface; and the flush water can swirl around on the upper part 18a of the waste receiving surface 18. As a result, the flush water can evenly reach the entire waste receiving surface 18 to wash away human waste adhered to the waste receiving surface 18. A variable flow rate device or the like is not used, and so a product cost increase can be suppressed.

In the flush toilet 1 according to the present embodiment, the rim discharge port 10 is located in the back region of the bowl 6 and configured to discharge flush water frontward, and so the waste receiving surface 18 in the front region of the bowl 6 can be washed with flush water having a sufficient water force.

In the flush toilet 1 according to the present embodiment, the width W1 of the upper part 18a of the waste receiving surface 18 is greater than the width W2 of the lower part 18b of the waste receiving surface 18 when viewed in plan; therefore, the upper part 18a of the waste receiving surface 18 can be larger; and more flush water can swirl around on the upper part 18a of the waste receiving surface 18.

In the flush toilet 1 according to the present embodiment, the height H1 of the upper part 18a of the waste receiving surface 18 is equal to the height of the lower part 18b of the waste receiving surface 18 or greater than the height H2 of the lower part 18b of the waste receiving surface 18 when viewed in side-view; therefore, the upper part 18a of the waste receiving surface 18 can be larger; and more flush water can swirl around on the upper part 18a of the waste receiving surface 18.

In the flush toilet 1 according to the present embodiment, the boundary X between the upper part 18a and the lower part 18b of the waste receiving surface 18 is inclined downward toward the front when viewed in side-view; therefore, the upper part 18a of the waste receiving surface 18 in the front region of the bowl 6 can be larger; and more flush water can swirl around on the upper part 18a of the waste receiving surface 18.

In the flush toilet 1 according to the present embodiment, the incline angle of the upper part 18a of the waste receiving surface 18 relative to the horizontal plane is smaller in the front region of the bowl 6 than in the back region of the bowl 6 when viewed in side-view, and so more flush water can swirl around on the upper part 18a of the waste receiving surface 18 in the front region of the bowl 6.

In the flush toilet 1 according to the present embodiment, the width of the upper part 18a of the waste receiving surface 18 is set so that one of the left region or the right region of the bowl 6 at which the rim discharge port 10 is located has the width w1 that is greater than the width w2 of the other of the left region or the right region of the bowl 6 when viewed in plan; therefore, the flush water that was discharged from the rim discharge port 10 and has traveled one lap can swirl around on the upper part 18a of the waste receiving surface 18 to be guided into the front region of the bowl 6.

Various changes and modifications are possible within the scope of the technical ideas described in the claims without limiting the embodiments of the present invention described above.

Claims

1. A flush toilet configured to discharge human waste by flushing with flush water, the flush toilet comprising:

a bowl including a waste receiving surface configured to receive human waste, a rim located above the waste receiving surface, and a standing water part located below the waste receiving surface, the standing water part being configured so that a standing water surface forms inside the standing water part; and

a drain trap pipe line connected to a lower part of the bowl, the drain trap pipe line being configured to discharge human waste, wherein

the rim includes an inner circumferential surface, and one rim discharge port configured to generate a swirling flow of flush water by discharging the flush water along the inner circumferential surface of the rim,

the waste receiving surface includes an upper part and a lower part,

the upper part of the waste receiving surface has a concave shape extending around an entire circumference of the bowl, and

the lower part of the waste receiving surface has a convex shape extending around the entire circumference of the bowl.

2. The flush toilet according to claim 1, wherein the rim discharge port is located in a back region of the bowl and configured to discharge the flush water frontward.

3. The flush toilet according to claim 1, wherein a width of the upper part of the waste receiving surface is greater than a width of the lower part of the waste receiving surface when viewed in plan.

4. The flush toilet according to claim 3, wherein a height of the upper part of the waste receiving surface is equal to a height of the lower part of the waste receiving surface or greater than the height of the lower part of the waste receiving surface when viewed in side-view.

5. The flush toilet according to claim 1, wherein a boundary between the upper part and the lower part of the waste receiving surface is inclined downward toward a front of the bowl when viewed in side-view.

6. The flush toilet according to claim 1, wherein an incline angle of the upper part of the waste receiving surface relative to a horizontal plane when viewed in side-view is smaller in a front region of the bowl than in a back region of the bowl.

7. The flush toilet according to claim 1, wherein

the rim discharge port is located in one of a left region or a right region of the bowl when viewed in plan, and

a width of the upper part of the waste receiving surface is larger in the one of the left region or the right region than in the other of the left region or the right region when viewed in plan.

8. The flush toilet according to claim 2, wherein a width of the upper part of the waste receiving surface is greater than a width of the lower part of the waste receiving surface when viewed in plan.

9. The flush toilet according to claim 8, wherein a height of the upper part of the waste receiving surface is equal to a height of the lower part of the waste receiving surface or greater than the height of the lower part of the waste receiving surface when viewed in side-view.

10. The flush toilet according to claim 2, wherein a boundary between the upper part and the lower part of the waste receiving surface is inclined downward toward a front of the bowl when viewed in side-view.

11. The flush toilet according to claim 2, wherein an incline angle of the upper part of the waste receiving surface relative to a horizontal plane when viewed in side-view is smaller in a front region of the bowl than in the back region of the bowl.

12. The flush toilet according to claim 2, wherein

the rim discharge port is located in one of a left region or a right region of the bowl when viewed in plan, and

a width of the upper part of the waste receiving surface is larger in the one of the left region or the right region than in the other of the left region or the right region when viewed in plan.