阅读说明：本技术 冲落式冲水大便器 (Flushing toilet ) 是由 今泉祥子 于 2021-03-16 设计创作，主要内容包括：本发明提供一种冲落式冲水大便器,即使清洗水量相对较少也能够维持有效的污物排出性能。具体而言,本发明的冲落式冲水大便器具备承接污物的盆部及连接于盆部下方部的排水弯管管路。排水弯管管路具有：入口管部,其一端侧与盆部的下方部连续或连接；弯管上升管部,其一端侧与入口管部的另一端侧连续或连接而形成上升流路；以及弯管下降管部,其一端侧与弯管上升管部的另一端侧连续或连接而形成下降流路。在与上升流路的流路方向垂直的截面中,在上升流路的下游侧的一部分形成有扩大部,其流路截面积比上升流路的上游侧的流路截面积大。在上升流路的下游端及/或下降流路的上游侧形成有缩小部,其流路截面积比上升流路的上游侧的流路截面积小。(The invention provides a flush toilet capable of maintaining effective waste discharge performance even if the amount of cleaning water is relatively small. Specifically, the flush toilet of the present invention includes a bowl portion for receiving waste, and a drain trap pipe line connected to a lower portion of the bowl portion. The drain trap pipe line has: an inlet pipe part, one end side of which is continuous with or connected with the lower part of the basin part; an elbow ascending pipe section having one end side connected to the other end side of the inlet pipe section to form an ascending flow path; and a bent-tube descending tube portion having one end side connected to the other end side of the bent-tube ascending tube portion to form a descending flow path. In a cross section perpendicular to the flow path direction of the ascending flow path, an enlarged portion having a flow path cross-sectional area larger than that of the ascending flow path on the upstream side is formed in a part of the downstream side of the ascending flow path. A narrowing portion having a smaller flow path cross-sectional area than the flow path cross-sectional area of the ascending flow path on the upstream side is formed at the downstream end of the ascending flow path and/or on the upstream side of the descending flow path.)

1. A flush toilet includes a bowl portion for receiving waste and a drain trap pipe connected to a lower portion of the bowl portion,

the drain trap pipe line has: an inlet pipe portion, one end side of which is continuous with or connected to the lower portion of the bowl portion;

an elbow ascending pipe section having one end side connected to the other end side of the inlet pipe section to form an ascending flow path;

and a bent pipe descending pipe portion having one end side connected to the other end side of the bent pipe ascending pipe portion to form a descending flow path,

an enlarged portion having a larger flow path cross-sectional area than the flow path cross-sectional area on the upstream side of the ascending flow path is formed in a portion of the ascending flow path on the downstream side thereof in a cross section perpendicular to the flow path direction of the ascending flow path,

a narrowed portion having a flow path cross-sectional area smaller than that of the upstream side of the ascending flow path is formed at the downstream end of the ascending flow path and/or the upstream side of the descending flow path.

2. The flush toilet according to claim 1,

the expansion portion expands above the ascending flow path.

3. The flush toilet according to claim 2,

an upstream end of the top surface of the enlarged portion is located at a position higher than a highest reaching position of the bottom surface of the ascending flow path.

4. The flush toilet according to claim 2 or 3,

the flow path height of the narrowing portion is lower than the flow path height on the upstream side of the ascending flow path.

5. The flush toilet according to any one of claims 1 to 4,

at least a part of a top surface of the enlarged portion of the ascending flow path is formed by a wall surface extending in a substantially vertical direction.

6. The flush toilet according to any one of claims 1 to 5,

at least a part of a top surface of the enlarged portion of the ascending flow path has a curved shape that is convex upward in a cross section perpendicular to the flow path direction of the ascending flow path.

7. The flush toilet according to claim 6,

at least a part of the top surface of the constricted portion has a curved shape that protrudes upward in a cross section perpendicular to the flow path direction of the ascending flow path or the descending flow path.

8. The flush toilet according to any one of claims 1 to 6,

in a cross section perpendicular to the flow path direction of the descending flow path, a 2 nd expanded portion having a flow path cross-sectional area larger than that of the expanded portion is formed in a part of the descending flow path on the downstream side.

Technical Field

The present invention relates to a flush toilet, and more particularly to a flush toilet with excellent water saving performance.

Background

Conventionally, as one type of flush toilet, a flush toilet is known. A flush toilet is a flush toilet based on the principle that waste is flushed by the action of running water generated by the fall of water.

For example, patent document 1 discloses a flush toilet in which a protrusion is provided on a drain pipe cover connected to a drain trap pipe line to suppress the occurrence of siphon in an underground pipe. Patent document 2 discloses a flush toilet in which the bottom surface of the upstream end side of the trap descending pipe portion of the drain trap pipe is formed as a downward inclined surface.

The discharge performance of waste (excrement, toilet paper, etc.) in a flush toilet is mainly determined by the water head of accumulated water in the bowl portion generated when the toilet is washed. More specifically, the discharge performance of the contaminants is determined by a water level difference between a water level of accumulated water before the start of washing and a maximum water level of accumulated water when the washing water is supplied after the start of washing. Generally, the larger the water head difference, the higher the dirt discharge performance.

Patent document

Patent document 1: japanese laid-open patent publication No. 2016-176320

Patent document 2: japanese unexamined patent publication No. 2018-112004

Disclosure of Invention

In recent years, flush toilets have been required to be further water-saving. However, in the flush toilet, if the amount of flush water is reduced, a sufficient water head difference cannot be secured, and the waste discharge performance may be reduced.

Here, the drain trap pipe generally includes: an inlet pipe part, one end side of which is continuous with or connected with the lower part of the basin part; an elbow ascending pipe section having one end side connected to the other end side of the inlet pipe section to form an ascending flow path; and a bent-tube descending tube portion having one end side connected to the other end side of the bent-tube ascending tube portion to form a descending flow path.

As shown in fig. 9, in the conventional elbow ascending pipe portion, the cross-sectional area of the ascending flow path is substantially constant with respect to the cross-section perpendicular to the flow path direction of the ascending flow path. In such a conventional elbow ascending pipe portion, if water saving is performed, there is a possibility that the dirt cannot ascend the ascending pipe portion and returns to the inlet pipe portion or the like.

In this way, in the flush toilet, the shape of the drain trap pipe, particularly the shape of the flow path of the trap rising pipe portion, is in need of improvement in terms of water saving and improvement in waste discharge performance.

The object of the present invention is to provide a flush toilet capable of maintaining effective waste discharge performance even with a relatively small amount of wash water.

The present invention is a flush toilet bowl including a bowl portion for receiving waste and a drain trap pipe connected to a lower portion of the bowl portion, the drain trap pipe including: an inlet pipe portion, one end side of which is continuous with or connected to the lower portion of the bowl portion; an elbow ascending pipe section having one end side connected to the other end side of the inlet pipe section to form an ascending flow path; and an elbow descending pipe portion having one end side connected to the other end side of the elbow ascending pipe portion to form a descending flow path, wherein an enlarged portion having a flow path cross-sectional area larger than the flow path cross-sectional area on the upstream side of the ascending flow path is formed in a part of the downstream side of the ascending flow path in a cross section perpendicular to the flow path direction of the ascending flow path, and a narrowed portion having a flow path cross-sectional area smaller than the flow path cross-sectional area on the upstream side of the ascending flow path and/or the downstream side of the descending flow path is formed at the downstream end of the ascending flow path and/or the upstream side of the descending flow path.

According to the present invention, when the washing water and the filth flow into the elbow rising pipe portion of the drain elbow pipe line at the time of toilet washing, the scattering of the filth (breaking of the lumps) is promoted in the enlarged portion where the flow path cross-sectional area becomes large. Then, in the reduced portion where the flow path cross-sectional area is reduced, the cleaning water and the dirt diffused in the enlarged portion are collected again and efficiently rectified. This acts to maintain effective dirt discharge performance even when the amount of washing water is relatively small.

Preferably, the enlarged portion is enlarged above the ascending flow path.

Accordingly, when the wash water and the waste flow into the elbow rising pipe portion of the drain elbow pipe line at the time of toilet cleaning, a part of the wash water flows into the region enlarged on the upper side in the enlarged portion where the flow path cross-sectional area on the upper side is enlarged. By the behavior of the washing water, a rotational force can be applied to the dirt passing through the enlarged portion, and the dirt can be rolled in a direction (a longitudinal direction) to move over the highest arrival position of the ascending flow path. This acts to maintain effective dirt discharge performance even when the amount of washing water is relatively small.

If the upstream side end of the top surface of the enlarged portion is located at a position lower than the highest arrival position of the bottom surface of the ascending flow path, a rotational force can be more effectively given to dirt passing through the enlarged portion. On the other hand, if the upstream end of the top surface of the enlarged portion is located at a position higher than the highest reaching position of the bottom surface of the ascending flow path, a constant (or less than a constant) flow path cross-sectional area can be maintained in a longer region in the ascending flow path, and therefore potential energy due to a water head can be utilized more efficiently (with low loss).

Preferably, the flow path height of the narrowing portion is lower than the flow path height on the upstream side of the ascending flow path. That is, the flow path cross-sectional area of the narrowed portion is preferably narrowed in the vertical direction.

Accordingly, since the direction in which the flow path cross-sectional area is expanded in the expanding portion coincides with the direction in which the flow path cross-sectional area is reduced in the reducing portion, the cleaning water and dirt diffused in the expanding portion are more effectively rectified in the reducing portion. This can improve the dirt discharge performance.

Preferably, at least a part of a top surface of the enlarged portion of the ascending flow path is formed by a wall surface extending in a substantially vertical direction.

According to the present invention, when the enlarged portion is formed in such a manner, a rotational force can be more effectively applied.

Preferably, at least a part of a top surface of the enlarged portion of the ascending flow path has a curved shape that is convex upward in a cross section perpendicular to the flow path direction of the ascending flow path.

Thus, even if the cross-sectional area of the flow path in the enlarged portion is increased, excessive disturbance of the flow of the washing water and the dirt in the enlarged portion is effectively suppressed.

In this case, it is preferable that at least a part of the top surface of the reduced portion has a curved shape which is convex upward in a cross section perpendicular to the flow path direction of the ascending flow path or the descending flow path.

Accordingly, the top surface of the ascending flow path (and the descending flow path) can be smoothly formed from the enlarged portion to the reduced portion, and the cleaning water and dirt spread in the enlarged portion can be more effectively rectified. This also improves the dirt discharge performance.

Preferably, a 2 nd expanded portion having a larger flow path cross-sectional area than the expanded portion is formed in a portion of the descending flow path on the downstream side thereof with respect to a cross section perpendicular to the flow path direction of the descending flow path.

This can suppress the occurrence of a siphon phenomenon in the descending flow path.

According to the present invention, a flush toilet that can maintain effective waste discharge performance even with a relatively small amount of flush water can be provided.

Drawings

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

Fig. 2 is a sectional view taken along line II-II of fig. 1 (the water storage tank 4 is not shown).

Fig. 3 is a sectional view taken along line III-III of fig. 2.

Fig. 4 is a sectional view taken along line IV-IV of fig. 2.

Fig. 5 is a cross-sectional view taken along line V-V of fig. 2.

Fig. 6 is a sectional view taken along line VI-VI of fig. 2.

Fig. 7 is an explanatory diagram of the operation of the flush toilet of the present embodiment.

Fig. 8 is an explanatory diagram of another function of the flush toilet of the present embodiment.

Fig. 9 is a sectional view showing the shape of an ascending flow path of a conventional elbow ascending pipe portion.

Description of the reference numerals

1-flush type flush toilet; 2-the toilet body; 2 a-water supply port; 4-a water storage tank; 8-a basin part; 12-a water accumulation part; 14-a drain trap line; 14 a-an inlet tube portion; 14 b-elbow riser section; 14 c-a down leg portion of the elbow; 16-a dirt receiving surface; 18-a rim portion; 20-a water conduit; 21-a main water path; 23 a-1 st basin rim water conduit; 23 b-2 nd basin rim water conduit; 24 a-1 st water discharge portion; 24 b-2 nd water discharge portion; 25-the bottom surface of the water channel is communicated with the basin edge; 30-ascending flow path; 32-an enlarged portion; 33-a substantially vertical wall; 34-a substantially horizontal wall; 36-a narrowing section; 40-descending flow path; 42-enlargement 2; a-an upstream side end of the top surface of the enlarged portion; b-highest arrival position of bottom surface of ascending flow path.

Detailed Description

(integral constitution)

Hereinafter, a flush toilet according to an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a plan view showing a flush toilet according to an embodiment of the present invention, fig. 2 is a sectional view taken along line II-II of fig. 1 (a water storage tank 4 is not shown), fig. 3 is a sectional view taken along line III-III of fig. 2, fig. 4 is a sectional view taken along line IV-IV of fig. 2, fig. 5 is a sectional view taken along line V-V of fig. 2, fig. 6 is a sectional view taken along line VI-VI of fig. 2, fig. 7 is an explanatory view of an operation of the flush toilet of the present embodiment, and fig. 8 is an explanatory view of other operations of the flush toilet of the present embodiment.

As shown in fig. 1 to 7, a flush toilet 1 according to an embodiment of the present invention includes a toilet main body 2 made of pottery or the like. A reservoir tank 4 as a source of wash water is provided above the rear side of the toilet main body 2. The water storage tank 4 is connected to a water supply source (not shown) such as a water supply line.

In the following description, the right side when the toilet main unit 2 is viewed from the front is referred to as "right side", and the left side when the toilet main unit 2 is viewed from the front is referred to as "left side".

The washing operation is started by operating an operation lever (not shown) provided in the water storage tank 4. Specifically, a drain valve (not shown) of the reservoir tank 4 is opened by the operation of the operation lever, and a predetermined amount of flush water is supplied from the reservoir tank 4 to a supply port 2a provided on the rear side of the toilet main unit 2.

Here, the predetermined amount of wash water is about 3.8 to 6.0 liters, which is smaller than the amount of wash water (e.g., about 13 liters) of a conventional general wash down toilet.

Instead of the reservoir tank 4, another water supply device such as a flush valve that can supply a predetermined amount of cleaning water may be used.

A bowl portion 8 is formed at the front upper portion of the toilet main body 2. The bowl portion 8 has a dirt receiving surface 16 formed in a bowl shape and a bowl edge portion 18 formed at an upper edge portion thereof and discharging water toward the dirt receiving surface 16.

The rim portion 18 of the present embodiment is formed substantially over the entire periphery of the upper edge portion of the bowl portion 8 and projects inward. The bowl rim water passage bottom surface 25 is formed in a substantially flat rack shape substantially horizontally inward along substantially the entire periphery of the bowl portion 8. With this configuration, the washing water flowing on the rim water passage bottom surface 25 can form a water flow that circulates around the upper portion of the bowl portion 8, and the washing water can be guided to each region in the bowl portion 8 relatively uniformly.

A water conduit 20 is provided inside the toilet main body 2 to guide wash water introduced from a supply port 2a provided on the rear side of the toilet main body 2 into the bowl portion 8 through the bowl rim water passage bottom surface 25.

The water conduit 20 includes a main water conduit 21, a 1 st bowl rim water conduit 23a, a 1 st water discharge portion 24a, a 2 nd bowl rim water conduit 23b, and a 2 nd water discharge portion 24 b.

As shown in fig. 1, main water passage 21 is formed from below water storage tank 4 toward the front of the toilet. Main water channel 21 is branched into a 1 st bowl rim water conduit 23a and a 2 nd bowl rim water conduit 23b on the downstream side. Thus, the wash water supplied to the main water passage 21 flows into the 1 st and 2 nd rim water conduits 23a and 23 b.

The 1 st bowl rim water conduit 23a is formed along the bowl rim portion 18 from the rear of the bowl portion 8 toward the left side. A 1 st water discharge portion 24a is formed at a downstream end of the 1 st rim water conduit 23a (e.g., near the left center of the rim portion 18).

Thus, the washing water flowing from the main water channel 21 into the 1 st rim water channel 23a flows counterclockwise in plan view, then flows from the 1 st water discharge portion 24a onto the rim water channel bottom surface 25, and is discharged onto the waste receiving surface 16 of the bowl portion 8.

The 2 nd rim water conduit 23b is formed at the rear of the bowl portion 8 and has a curved portion that curves the flow direction of the washing water. A 2 nd water discharge portion 24b is formed at a downstream end of the 2 nd rim water conduit 23b (for example, at the right rear side of the rim portion 18).

Thus, the washing water flowing from the main water channel 21 into the 2 nd rim water channel 23b flows clockwise in plan view, then bends (reverses) the flow direction at the bent portion and flows counterclockwise, and then flows from the 2 nd water discharge portion 24b onto the rim water channel bottom surface 25 and is discharged onto the dirt receiving surface 16 of the bowl portion 8.

In this way, the flush toilet 1 of the present embodiment discharges wash water from the 1 st and 2 nd water discharge portions 24a and 24b provided in the bowl edge portion 18, and generates a swirling flow in the waste receiving surface 16 of the bowl portion 8, thereby washing the bowl portion 8.

(construction of the Drain trap pipe line 14)

A water accumulation portion 12 (a portion below the bowl portion) is formed below the bowl portion 8, and a predetermined amount of accumulated water is accumulated. The water accumulation surface of the initial water level is denoted by W0. One end side of an inlet pipe portion 14a of the drain trap pipe 14 is connected or connected to the lower end of the water accumulating portion 12. The accumulated water functions as a water seal to prevent the backflow of odor and the like from the drain trap pipe 14 toward the bowl portion 8.

The other end of the inlet pipe portion 14a is continuous with or connected to one end of the elbow ascending pipe portion 14b forming the ascending flow path 30. The other end side of the elbow ascending pipe portion 14b is continuous with or connected to one end side of the elbow descending pipe portion 14c forming the descending flow path 40. The other end side of the elbow descending pipe portion 14c is connected to a discharge pipe (not shown) provided on the ground.

As shown in fig. 2, the bottom surface (the lowermost surface of the pipe) of the inlet pipe portion 14a is formed as a curved surface which is convex downward in side view, and the bottom surface of the region of the upstream end of the elbow ascending pipe portion 14b is also formed as a curved surface which is convex downward, and both are smoothly continuous or continuous with each other.

In a cross section perpendicular to the flow path direction of the inlet pipe portion 14a, the bottom surface (the lowermost surface of the pipe) of the inlet pipe portion 14a is formed as a curved surface that is convex downward.

In a similar manner, as shown in fig. 2, the inlet pipe portion 14a is also formed with a curved surface that is convex downward on the top surface (the uppermost surface of the pipe) in a side view, and the elbow ascending pipe portion 14b is also formed with a curved surface that is convex downward on the top surface in the region of the upstream end thereof, and both are smoothly continuous or continuous with each other.

In a cross section perpendicular to the flow path direction of the inlet pipe portion 14a, the top surface of the inlet pipe portion 14a (the uppermost surface of the pipe) is formed as an upwardly convex curved surface.

The left and right side surfaces of the inlet pipe portion 14a and the left and right side surfaces of the region of the upstream side end of the elbow ascending pipe portion 14b are also smoothly continuous or continuous with each other.

The bent-tube ascending tube portion 14b has a straight tube shape extending obliquely upward in the middle region, and the cross section perpendicular to the flow path direction of the ascending flow path 30 is constant in the cross-sectional shape shown in fig. 3 (flow path width 78mm, flow path height 63 mm).

In the present embodiment, the cross section perpendicular to the flow path direction of the ascending flow path 30 in the region (curved region) of the upstream end of the elbow ascending pipe portion 14b is also the same as the cross sectional shape shown in fig. 3.

An enlarged portion 32 having a larger flow passage cross-sectional area than the flow passage cross-sectional area on the upstream side of the ascending flow passage 30 (cross-sectional area of the cross-sectional shape shown in fig. 3) is formed in a part of the downstream side of the ascending flow passage 30. The enlarged portion 32 is enlarged above the ascending flow path 30, and as shown in fig. 2, an upstream end a of a top surface of the enlarged portion 32 is located at a position higher than a highest reaching position B of a bottom surface of the ascending flow path 30 (a height difference is about 15 mm).

More specifically, the top surface of the enlarged portion 32 of the present embodiment is formed by a substantially vertical wall surface 33 extending in a substantially vertical direction from the upstream side end a and a substantially horizontal wall surface 34 extending in a substantially horizontal direction. The substantially vertical wall surface 33 has a flat shape, and the substantially horizontal wall surface 34 has a curved shape protruding upward at least in a region on the left-right direction center side in a cross section perpendicular to the flow path direction of the ascending flow path 30, similarly to the top surface of the ascending flow path 30 on the upstream side of the enlarged portion 32 (see fig. 3) (see fig. 4: flow path width 78mm, flow path maximum height 80 mm).

On the other hand, the cross-sectional shape of the bottom surface of the expanded portion 32 of the present embodiment, which is perpendicular to the flow path direction of the ascending flow path 30, is substantially constant (see fig. 4), and is substantially the same as the cross-sectional shape of the bottom surface of the ascending flow path 30 on the upstream side of the expanded portion 32 (see fig. 3).

In the present embodiment, a narrowed portion (see FIG. 5: 78mm in channel width and 60mm in channel maximum height) having a smaller channel cross-sectional area than the channel cross-sectional area on the upstream side of the ascending channel 30 (see FIG. 3) is further formed in the region of the downstream end of the ascending channel 30. In the present embodiment, as shown in fig. 5, the top surface of the constricted portion 36 has a curved shape that is convex upward in the region on the left-right direction center side in the cross section perpendicular to the flow path direction of the ascending flow path 30.

The substantially horizontal wall surface 34 (top surface) of the enlarged portion 32 and the top surface of the reduced portion 36 are smoothly continuous (or connected) so that the cross-sectional shape of the ascending flow path 30 smoothly transitions from the enlarged portion 32 to the reduced portion 36. The cross-sectional area of the flow path is constant in the reduced portion 36 (see fig. 5). (the cross-sectional area of the flow path from the downstream end of the expanding section 32 to the upstream end of the narrowing section 36 is smaller than the cross-sectional area of the flow path on the upstream side of the ascending flow path 30 (see FIG. 3) and larger than the cross-sectional area of the flow path of the narrowing section 36 (see FIG. 5))

The cross-sectional shape of the bottom surface is substantially the same from the enlarged portion 32 to the reduced portion 36 (see fig. 4 and 5). Thus, the bottom surface of the ascending flow path 30 is smoothly formed from the upstream end to the downstream end of the ascending flow path 30.

In the present embodiment, a 2 nd expanded portion 42 having a larger flow path cross-sectional area than the expanded portion 32 is formed in the descending flow path 40 (see FIG. 6: about 83mm in flow path width and 119mm in maximum flow path height). This configuration suppresses occurrence of a siphon phenomenon in the descending flow path 40.

From the downstream end of the narrowing portion 36 (the downstream end of the ascending flow path 30) to the upstream end of the 2 nd expanding portion 42, the top surface and the bottom surface of the descending flow path 40 smoothly and continuously transition, respectively, so that the flow path sectional area of the descending flow path 40 smoothly increases.

(action)

Next, an operation of the flush toilet of the present embodiment will be described.

When an operation button (not shown) of a flush operation panel (not shown) is operated to flush the toilet, a drain valve (not shown) provided in the reservoir tank 4 is opened, and a predetermined flush water amount (for example, 3.8 liters) from the reservoir tank 4 is supplied to the water conduit 20 in the toilet main body 2 from the supply port 2a on the rear side of the toilet main body 2.

Then, the washing water supplied to water conduit 20 is branched to 1 st and 2 nd basin rim water conduits 23a and 23b via main water conduit 21.

The wash water spouted from the 1 st spout portion 24a through the 1 st rim water conduit 23a flows over the rim water passage bottom surface 25 and rotates on the upper portion of the bowl portion 8, and descends from the rim water passage bottom surface 25 to the waste receiving surface 16 while rotating, thereby washing the bowl portion 8.

The washing water spouted from the 2 nd spout portion 24b through the 2 nd rim water conduit 23b also flows over the rim water passage bottom surface 25 and rotates on the upper portion of the bowl portion 8, and descends from the rim water passage bottom surface 25 to the waste receiving surface 16 while rotating, thereby washing the bowl portion 8.

The wash water descending while washing the bowl portion 8 is discharged from the drain trap pipe portion 14 together with the dirt.

Here, in the cross section perpendicular to the flow path direction of the ascending flow path 30 of the flush toilet 1 of the present embodiment, an enlarged portion 32 having a flow path cross-sectional area larger than the flow path cross-sectional area on the upstream side of the ascending flow path 30 is formed in a part of the downstream side of the ascending flow path 30, and a reduced portion 36 having a flow path cross-sectional area smaller than the flow path cross-sectional area on the upstream side of the ascending flow path 30 is formed at the downstream end of the ascending flow path 30 (and the upstream side of the descending flow path 40).

Thus, when the washing water and the filth flow into the trap rising pipe portion 14a of the drain trap pipe 14 at the time of toilet cleaning, as shown in fig. 7, the scattering of the filth (breaking of the lumps) is promoted in the enlarged portion 32 having the enlarged flow path cross-sectional area. In the reduced portion 36 having a reduced flow path cross-sectional area, the cleaning water and dirt diffused in the enlarged portion 32 are collected again and efficiently rectified. Based on this effect, effective dirt discharge performance can be maintained even if the amount of washing water is relatively small.

In the flush toilet 1 according to the present embodiment, the enlarged portion 32 is enlarged above the ascending flow path 30.

Thus, when the wash water and the waste flow into the elbow rising pipe portion 14a of the drain elbow pipe line 14 at the time of toilet cleaning, a part of the wash water flows into the area where the upper side is enlarged in the enlarged portion 32 where the upper side flow path cross-sectional area is enlarged. By the behavior of the washing water, a rotational force as indicated by an arrow in fig. 8 can be applied to the dirt passing through the enlarged portion 32, and the dirt can be rolled in a direction (a longitudinal direction) to move over the highest arrival position of the ascending flow path 30. Based on this effect, effective dirt discharge performance can be maintained even if the amount of washing water is relatively small.

In the flush toilet 1 according to the present embodiment, the upstream end a of the top surface of the enlarged portion 32 is located at a position higher than the highest arrival position B of the bottom surface of the ascending flow path 30.

This allows a constant flow path cross-sectional area to be maintained in a longer region in the ascending flow path 30, and thus makes it possible to utilize potential energy due to the drop height of water with higher efficiency (low loss).

In the flush toilet 1 according to the present embodiment, the flow path height of the reduced portion 36 is lower than the flow path height on the upstream side of the ascending flow path 30. That is, the flow path cross-sectional area of the narrowing portion 36 is narrowed in the vertical direction.

In this way, since the direction in which the flow path cross-sectional area is expanded in the expanded portion 32 coincides with the direction in which the flow path cross-sectional area is reduced in the reduced portion 36, the wash water and dirt diffused in the expanded portion 32 are more effectively rectified in the reduced portion 36. This can improve the dirt discharge performance.

In the flush toilet 1 according to the present embodiment, a part of the top surface of the enlarged portion 32 of the upward flow path 30 is formed by a substantially vertical wall surface 33 extending in a substantially vertical direction from the upstream side end a.

Thereby, the rotational force as shown by the arrow in fig. 8 can be more effectively provided to the filth.

In the flush toilet 1 according to the present embodiment, a part of the top surface of the enlarged portion 32 of the ascending flow path 30 is formed by the substantially horizontal wall surface 34, and has a curved shape that is convex in a cross section perpendicular to the flow path direction of the ascending flow path 30.

Thus, even if the cross-sectional area of the flow path is increased in the enlarged portion 32, the flow of the washing water and the dirt is effectively prevented from being excessively disturbed in the enlarged portion 32.

In the flush toilet 1 according to the present embodiment, the top surface of the reduced portion 36 also has a curved shape that is convex upward in a cross section perpendicular to the flow path direction of the ascending flow path 30.

Accordingly, the top surface of the ascending flow path 30 (and the descending flow path 40) can be smoothly formed from the enlarged portion 32 to the reduced portion 36, and the cleaning water and dirt spread in the enlarged portion 32 can be more effectively rectified. This also improves the dirt discharge performance.

In the flush toilet 1 according to the present embodiment, the 2 nd enlarged portion 42 having a larger flow passage cross-sectional area than the enlarged portion 32 is formed in a portion of the downward flow passage 40 on the downstream side thereof with respect to a cross-section perpendicular to the flow passage direction of the downward flow passage 40.

This can suppress the occurrence of a siphon phenomenon in the descending flow path 40.