Water-washable toilet

Abstract

To prevent deterioration of discharge performance by suppressing backflow of flush water at the bent portion of the drain trap. [Solution] The flush toilet according to the embodiment is a flush toilet that flushes the toilet body with flush water, and the toilet body comprises a bowl portion, a drain trap, a jet spout, and a discharge outlet. The bowl portion receives waste. The drain trap is connected to the bottom of the bowl portion. The jet spout sprays flush water toward the drain trap. The discharge outlet is connected to the drain trap and discharges waste from the toilet body. The drain trap comprises an ascending pipe, a bent pipe, and a descending pipe. The ascending pipe is connected to the bowl portion. The bent pipe is connected to the ascending pipe and has an ascending bent portion that rises rearward and a descending bent portion that descends rearward. The descending pipe is connected to the bent pipe. The drain trap forms a space that bulges rearward downstream of the apex of the bend in the bent pipe, and has a bulging portion that continues to the discharge outlet.

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION The disclosed embodiments relate to a flush toilet. [Background technology]

[0002] Conventionally, flush toilets include a so-called blowout type, which is equipped with a drain trap having an ascending pipe, a curved pipe, and a descending pipe, and which sprays flushing water with great force from a jet spout toward the drain trap to generate a powerful water flow, thereby blowing waste downstream without relying on siphon action (see, for example, Patent Document 1).

[0003] Additionally, in some flush toilets, the internal space downstream of the bent portion is expanded to make it easier to send waste backward (downstream) in the drain trap (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-206562 [Patent Document 2] Japanese Patent Application Publication No. 10-331239 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of the conventional flush toilets described above, in the case of blowout flush toilets, the jet discharge does not cause the flush water to diffuse, but instead flows through the rising pipe at a thin flux, which can cause the flush water to collide with the upper inner surface of the curved pipe near the top of the drain trap, causing some of the flush water to flow back.As a result, the flush water flowing back through the rising pipe can create resistance, reducing drainage performance.

[0006] It is also possible to strengthen the drainage power of the flush water by expanding the internal space downstream of the bent part of the drain trap, but simply expanding the internal space of the drain trap may cause the flush water to collide with the enlarged space and become trapped, which could actually reduce drainage performance.

[0007] One aspect of the embodiment aims to provide a flush toilet that can suppress backflow of flush water at the bent portion of the drain trap, thereby preventing a decline in drainage performance. [Means for solving the problem]

[0008] A flush toilet according to one aspect of the embodiment is a flush toilet that flushes the toilet body with flushing water, the toilet body comprising a bowl portion that receives waste, a drain trap connected to the bottom of the bowl portion, a jet spout that sprays flushing water from the front of the drain trap toward the drain trap, and an outlet connected to the drain trap that discharges waste from the toilet body, the drain trap comprising an ascending pipe connected to the bowl portion, a curved pipe connected to the ascending pipe and having an ascending bend that rises as it heads rearward and a descending bend that descends from the ascending bend as it heads rearward, and a descending pipe connected to the curved pipe, the drain trap forming a space that bulges out toward the rear downstream of the apex of the bend in the curved pipe and having a bulge that continues to the outlet.

[0009] With this configuration, a space is formed in the drain trap that bulges out as it moves rearward, so when flush water spurting from the jet spout reaches the downstream side of the bent apex of the drain trap, the flush water flows into the bulging section, i.e., the space that bulges out toward the rear. This makes it possible to suppress backflow of flush water in the bent section (bent pipe) of the drain trap. Furthermore, by suppressing the backflow of flush water in this way, it is possible to suppress a decrease in discharge performance.

[0010] Furthermore, in the flush toilet described above, the descending pipe has a protruding portion that protrudes rearward so as to be continuous with the descending bent portion and continues to the discharge outlet.

[0011] With this configuration, the section from the curved duct to the outlet is continuous, so flush water that flows into the bulging section is quickly guided to the outlet, and flush water does not stagnate in the bulging section. In this way, flush water does not stagnate in the bulging section, which further reduces the deterioration of discharge performance.

[0012] Furthermore, in the flush toilet described above, the protruding portion protrudes so as to extend horizontally rearward from the upper inner circumferential surface of the downward bent portion.

[0013] With this configuration, the protrusion protrudes horizontally from the curved pipeline, so that the cleaning water flowing along the upper inner surface of the downward bend at the position where it changes from the upper inner surface of the downward bend to the protrusion in the drain trap can be separated from the upper inner surface and sent into the space of the protrusion.

[0014] Furthermore, in the flush toilet described above, the protrusion is formed only on the rear side of the downcomer pipe.

[0015] With this configuration, the protrusion is formed only on the rear side of the descending pipe, in other words, the protrusion is formed only in the rear part of the descending pipe, so the rearward flow vector is larger and the flow of cleaning water toward the discharge outlet can be strengthened.

[0016] Furthermore, in the flush toilet described above, the lateral width of the protruding portion is approximately the same as the lateral width of the upward bent portion.

[0017] With this configuration, the lateral width of the protrusion is approximately the same as the lateral width of the upward bend, so that the cleaning water flowing through the upward bend can flow into the protrusion without causing pressure loss.

[0018] Furthermore, in the flush toilet described above, the curved pipe is composed of an ascending bend that rises as it moves rearward and a descending bend that descends from the ascending bend as it moves rearward, and the curvature of the upper inner circumferential surface of the descending bend, when viewed from the side, is smaller than the curvature of the upper inner circumferential surface of the ascending bend.

[0019] With this configuration, the upper inner surface of the downward bend, which collides with the flushing water that has reached downstream of the bend apex of the drain trap, has a gentle curve in side view, making it easier for the flushing water to be guided rearward; further, the upper inner surface of the upward bend, which is upstream of the downward bend, has a steeper curve in side view than the upper inner surface of the downward bend, making it harder for the flushing water to return upstream.

[0020] Furthermore, in the flush toilet described above, the downward bent portion has a distance between the upper end of the upper inner circumferential surface and the lower end of the lower inner circumferential surface in the flow path cross section that increases toward the downstream side in a side view.

[0021] This configuration prevents backflow of flush water that reaches downstream of the bent apex of the drain trap due to collision with the upper inner surface of the downward bent portion, and makes it easier to guide the flush water to the discharge outlet. [Effects of the Invention]

[0022] According to one aspect of the embodiment, backflow of flush water can be suppressed at the bent portion of the drain trap, and a decrease in drainage performance can be suppressed. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a side cross-sectional view showing a flush toilet according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] FIG. 3 is a side cross-sectional view showing the bulging portion and the protruding portion of the drain trap. [Figure 4A] FIG. 4A is a cross-sectional view taken along line BB in FIG. [Figure 4B] FIG. 4B is a cross-sectional view taken along line CC in FIG. [Figure 5A] FIG. 5A is an explanatory diagram of the flow of cleaning water in this example. [Figure 5B] FIG. 5B is an explanatory diagram of the flow of cleaning water in the comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0024] Embodiments of the flush toilet disclosed in this application will be described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below.

[0025] <Flush toilet> The overall structure of a flush toilet 1 according to this embodiment will be explained with reference to Figures 1 and 2. Figure 1 is a side cross-sectional view of a flush toilet 1 according to this embodiment. Figure 2 is a cross-sectional view taken along line AA in Figure 1.

[0026] As shown in Figures 1 and 2, a flush toilet 1 comprises a toilet body 2. The toilet body 2 is made of ceramic, for example. The toilet body 2 may also be made of resin, or a combination of ceramic and resin. The toilet body 2 is a so-called wall-mounted type that is attached to the wall of the toilet room. A water supply device such as a water storage tank 3, which is the source of flush water, is installed above the rear side of the toilet body 2.

[0027] The water storage tank 3 is connected to a water supply source (not shown), such as a water supply system. When the flushing operation is started by operating an operating lever (not shown) provided on the water storage tank 3, a drain valve (not shown) on the water storage tank 3 opens, and a predetermined amount of flush water (for example, 6 L) is supplied from the water storage tank 3 to a supply port 4 that opens at the top of the central rear side of the toilet body 2. Note that the supply port 4 need not be located in the center, but may also be formed off to the right or left of the front-to-rear center line.

[0028] Furthermore, the flush toilet 1 can be used in a water-saving flush toilet in which the amount of flush water supplied from the water storage tank 3 is in the range of 3L to 6L, preferably in a water-saving flush toilet in the range of 4.8L to 6L.

[0029] Furthermore, the water supply device such as the water storage tank 3 may be other water supply devices such as a flush valve that can supply a specified amount of flush water, in addition to the water storage tank 3 described above.

[0030] Furthermore, a bowl section 5 is formed at the upper front part of the toilet body 2, and a water conduit 6 is formed at the upper rear part of the toilet body 2 between a supply port 4 connected to the downstream end of the water storage tank 3 and a rim water conduit 11, which will be described later, and which directs flush water supplied from the water storage tank 3 from the supply port 4 to the rim water conduit 11. Note that the water conduit 6 and part of the flow path of the rim water conduit 11 may be formed by other structures such as a distributor.

[0031] The lower part of the bowl 5 is a water reservoir 7, which stores a predetermined amount of water, the initial water level of which is indicated by WL. The lower end of the water reservoir 7 is connected to the inlet of a drain trap 8, which extends rearward from the inlet.

[0032] The bowl portion 5 is formed in a bowl shape and includes a rim portion 10 that forms a rim water passage 11 for guiding flush water at the upper edge of the bowl surface that receives the waste.

[0033] The water conduit 6 extends forward from the supply port 4 and is connected to the rim water conduit 11. The water conduit 6 extends from the vicinity of the supply port 4, which is disposed approximately in the center of the toilet body 2, toward the bowl portion 5.

[0034] In the water conduit 6, the flush water W1 is well rectified, the directionality of the flush water W1 is increased, and the flush water W1 is discharged from the water conduit 6 as a regulated flow in the direction that tries to circulate around the rim water conduit 11, and as a flow with relatively strong water force.

[0035] Furthermore, part of the headrace 6 is formed so that it is parallel to part of the junction with the rim water passage 11. Near the outlet (spout) 10a of the headrace 6, this roughly matches the flow direction of the flush water W2 that attempts to circulate around the rim water passage 11, so the flush water W1 that flows out from the outlet 10a of the headrace 6 flows in roughly the same circling direction (circumferential direction) through the rim water passage 11, forming a flow that attempts to circulate around the rim water passage 11 while maintaining water force (a state in which the flow rate and flow speed are roughly maintained).

[0036] This prevents the flushing water W1 that joins the rim water passage 11 from the water conduit 6 from flowing in the opposite direction to the main flow (flushing water W2) of the rim water passage 11, and prevents the main flow (flushing water W2) from flowing down onto the bowl surface through the slit opening 14 described below.

[0037] The rim portion 10 is formed in an annular shape around the entire periphery as the upper edge of the bowl portion 5. The rim portion comprises a rim outer wall portion 12a, a rim upper wall portion 12b, and a rim inner wall portion 12c. The rim outer wall portion 12a forms the outer peripheral surface of the rim portion 10 and is formed as a standing wall that rises to its peak on the outer surface of the toilet body 2. The rim upper wall portion 12b forms a flat surface at the top of the rim portion 10. The rim inner wall portion 12c forms the inner peripheral surface of the rim portion 10 and extends downward slightly inward from the rim upper wall portion 12b.

[0038] A shelf portion 13 is formed at the bottom of the rim portion 10. The shelf portion 13 is formed as a generally flat surface within the rim portion 10 that extends outward from the upper edge of the bowl surface of the bowl portion 5, and is formed in an annular shape around substantially the entire circumference of the bowl portion 5.

[0039] A slit opening 14 is formed between the rim portion 10 and the bowl surface of the bowl portion 5. The slit opening 14, together with the rim inner wall portion 12c, opens downward to form a water outlet portion directed toward the bowl surface of the rim portion 10 below the rim water passage 11.

[0040] The drain trap 8 extending to the rear of the toilet body 2 includes an ascending pipe 81, a curved pipe 82, and a descending pipe 83. The upstream end of the ascending pipe 81 is connected to the bowl section 5 (the water collection section 7). The ascending pipe 81 is a pipe that is inclined so that it rises toward the rear.

[0041] The upstream end of the curved pipe 82 is connected to the downstream end of the ascending pipe 81. The curved pipe 82 has an ascending bent portion 821 and a descending bent portion 822. The ascending bent portion 821 is a portion that continues from the ascending pipe 81 and is inclined so as to ascend as it extends rearward. The descending bent portion 822 is a portion that continues from the ascending bent portion 821 and is inclined so as to descend as it extends rearward. The connection portion between the ascending bent portion 821 and the descending bent portion 822 forms the bent apex, the highest portion of the curved pipe 82.

[0042] The descending pipe 83 is connected to the downstream end of the bent pipe 82, i.e., the downstream end of the descending bent section 822. The descending pipe 83 is a pipe that slopes downward as it heads rearward. The downstream end of the descending pipe 83 is connected to the outlet 9, which discharges flush water and waste from the toilet body 2. The outlet 9 is connected to facility piping, which is piping outside the flush toilet 1.

[0043] A jet water outlet 20 that sprays flushing water toward the drain trap 8 (rising pipe 81) is formed in front of the rising pipe 81 of the drain trap 8. As shown in Figure 2, the jet water outlet 20 is formed at the outlet of the jet water conduit 21, and sprays the flushing water from the jet water conduit 21 with strong water force, thereby generating a siphon effect.

[0044] Here, the flush water ejected from the jet outlet 20 flows through the rising pipe 81 without diffusing and with a thin flow rate, which can cause it to collide with the upper inner circumferential surface near the bent apex of the drain trap 8, causing some of the flush water to flow back. When flush water flows back in this way, the backflowing flush water can create resistance and reduce drainage performance. For this reason, in this embodiment, the drain trap 8 is designed to be able to suppress the backflow of flush water and prevent a decrease in drainage performance.

[0045] <Drain trap> The structure of the drain trap 8 will now be described in detail with reference to Figures 3 to 5B. Figure 3 is a side cross-sectional view showing the bulging portion 84 and protruding portion 85 of the drain trap 8. Figure 4A is a cross-sectional view taken along line BB in Figure 3. Figure 4B is a cross-sectional view taken along line CC in Figure 3. Figure 5A is an explanatory diagram of the flow of flush waters W31 and W32 in this example. Figure 5B is an explanatory diagram of the flow of flush waters W31, W32, and W33 in a comparative example.

[0046] 3 and as described above, the drain trap 8 includes an ascending pipe line 81, a bent pipe line 82, and a descending pipe line 83. The bent pipe line 82 has an ascending bent portion 821 and a descending bent portion 822. The junction of the ascending bent portion 821 and the descending bent portion 822 forms the bent apex of the bent pipe line 82.

[0047] 3, the ascending pipeline 81 is a pipeline from the reference line L1 to the reference line L2, the bent pipeline 82 is a pipeline from the reference line L2 to the reference line L4, and the descending pipeline 83 is a pipeline from the reference line L4 to the reference line L5. In the bent pipeline 82, the ascending bent portion 821 is a portion from the reference line L2 to the reference line L3, and the descending bent portion 822 is a portion from the reference line L3 to the reference line L4. The top of the bend in the bent pipeline 82 is located at the position of the reference line L3.

[0048] The drain trap 8 also has a bulging portion 84 and a protruding portion 85. The bulging portion 84 is a portion that forms a space that bulges out toward the rear downstream of the apex of the bend of the curved pipe 82. The bulging portion 84 is also continuous downstream of the apex of the bend of the curved pipe 82 to the discharge outlet 9 so as not to interfere with the flow of flush water from the apex of the bend. Here, "continuous" refers to a shape that does not generate a flow of flush water in the opposite direction to the flow toward the discharge outlet 9, for example, by not having any protrusions that would interfere with the flow of flush water between the curved pipe 82 and the discharge outlet 9.

[0049] The protruding portion 85 is a portion that protrudes rearward so as to be continuous with the downward bent portion 822. The protruding portion 85 also continues to the outlet 9 so as not to obstruct the flow of flush water. Such a protruding portion 85 is included in the bulging portion 84.

[0050] Furthermore, the protrusion 85 protrudes so as to extend horizontally rearward from the upper inner circumferential surface of the descending bent portion 822. The cross-sectional shape of the drain trap 8 is approximately circular. For this reason, the inner surface of the upper half of the drain trap 8 (the ascending pipe line 81, the bent pipe line 82 (the ascending bent portion 821 and the descending bent portion 822), and the descending pipe line 83) is referred to as the upper inner circumferential surface (also referred to as the upper surface), and the inner surface of the lower half is referred to as the lower inner circumferential surface (also referred to as the lower surface).

[0051] 4A and 4B, protrusion 85 is formed only on the rear side of descending pipe line 83. In other words, protrusion 85 protrudes only toward the rear of descending pipe line 83, and does not protrude toward the sides of descending pipe line 83. Note that a reference line (reference line L3) that divides each of pipe lines 81, 82, and 83 is also shown in FIGS.

[0052] As shown in FIG. 4B, the lateral width of the protruding portion 85, that is, the width in the left-right direction, is approximately the same as the lateral (left-right) width of the ascending bent portion 821 of the bent pipe .

[0053] In this embodiment, the curved pipe 82 is a pipe having a mountain shape in a side view, which is composed of an upward curved portion 821 and a downward curved portion 822. As shown in Fig. 5A, the downward curved portion 822 has an upper inner circumferential surface 822a with a smaller curvature in a side view than the upper inner circumferential surface 821a of the upward curved portion 821. That is, the upper inner circumferential surface 822a of the downward curved portion 822 has a gentler curve than the upper inner circumferential surface 821a of the upward curved portion 821.

[0054] In addition, in the downward bent portion 822, the distance between the upper end of the upper inner circumferential surface and the lower end of the lower inner circumferential surface in the flow path cross section increases toward the downstream side in a side view. In other words, the pipe diameter of the downward bent portion 822 widens toward the downstream side.

[0055] <Flow of flushing water in the drain trap> Here, the flow patterns of flush water W31, W32, and W33 in drain trap 8 will be described with reference to Figures 5A and 5B. Note that Figure 5A shows the flow patterns of flush water W31, W32 in this example (drain trap 8), and Figure 5B shows the flow patterns of flush water W31, W32, and W33 in a comparative example (conventional drain trap 40).

[0056] As shown in Figure 5A, in the drain trap 8 of this example, flush water W31 flowing with great force through the rising pipe 81 by the jet spout 20 (see Figure 3) flows into the bulging part 84 when it reaches the downstream side of the bent apex of the curved pipe 82 (the part of reference line L3). For this reason, flush water W32 that flows into the bulging part 84 flows to the discharge outlet 9 without being obstructed along the way. In this case, because the protrusion 85 is formed, flush water W32 that flows into the bulging part 84 is quickly guided to the discharge outlet 9 and does not stagnate in the bulging part 84.

[0057] 5B, in drain trap 40 of the comparative example, flush water W31 flowing with great force through ascending pipe 41 flows into descending pipe 43 like flush water W32 when it reaches the downstream side of the bent apex of bent pipe 42 (the location of reference line L3), but a component (flush water W33) is generated that collides with the upper inner circumferential surface of descending bend 422 and returns to ascending bend 421. In this way, in drain trap 40 of the comparative example, the flow of flush water W31 is obstructed by the backflowing flush water W33.

[0058] In the drain trap 8 of this example, there is no backflow of the flush water W31 as in the drain trap 40 of the comparative example, and therefore the flow of the flush water W31 is not impeded.

[0059] Thus, with the flush toilet 1 according to this embodiment, a space is formed in the drain trap 8 that bulges out as it heads rearward, so when the flush water W3 spurting from the jet spout 20 reaches the downstream side of the bent apex of the drain trap 8, the flush water W3 that has reached it flows into the bulging section 84, i.e., into the space that bulges out towards the rear. This makes it possible to prevent the flush water W3 from flowing back in the bent section (bent pipe 82) of the drain trap 8. Furthermore, by preventing the flush water W3 from flowing back in this way, it is possible to prevent a decline in discharge performance.

[0060] Furthermore, because there is a continuity between the curved duct 82 and the discharge port 9, the flushing water W32 that flows into the bulging portion 84 is quickly guided to the discharge port 9, and the flushing water W32 does not stagnate in the bulging portion 84. In this way, because the flushing water W32 does not stagnate in the bulging portion 84, the deterioration of discharge performance can be further suppressed.

[0061] Furthermore, since the protrusion 85 protrudes so as to extend horizontally from the curved pipeline 82, the cleaning water W32 flowing along the upper inner surface 822a of the downward curved portion 822 at the position where the drain trap 8 changes from the upper inner surface 822a of the downward curved portion 822 to the protrusion 85 can be peeled off from the upper inner surface 822a and sent into the space of the protrusion 85.

[0062] Furthermore, since the protrusion 85 is formed only on the rear side of the descending pipe 83, in other words, since the protrusion 85 is formed only in the rear portion of the descending pipe 83, the flow vector toward the rear is increased, and the flow of the cleaning water W32 toward the discharge outlet 9 can be strengthened.

[0063] Furthermore, since the lateral width of the protrusion 85 is approximately the same as the lateral width of the upward bend 821, the cleaning water W31 flowing through the upward bend 821 can flow into the protrusion 85 without causing any pressure loss.

[0064] In addition, the upper inner surface 822a of the downward bend 822, with which the flushing water W31 that reaches downstream of the bend apex of the drain trap 8 collides, has a gentle curve in side view, making it easy for the flushing water W31 to be guided rearward, and the upper inner surface 821a of the upward bend 821 upstream of the downward bend 822 has a steeper curve in side view than the upper inner surface 822a of the downward bend 822, making it difficult for the flushing water W31 to return upstream.

[0065] In addition, since the pipe diameter of the downward bent portion 822 widens toward the downstream side, backflow due to collision of the cleaning water W31 that has reached the downstream side of the bent apex of the drain trap 8 with the upper inner surface 822a of the downward bent portion 822 is suppressed, and the cleaning water W32 is more easily guided to the discharge outlet 9.

[0066] In the above embodiment, the flush toilet 1 (toilet body 2) is a wall-hung type, but this is not limited to this and it may be, for example, a floor-standing type. In this case, the discharge port 9 is located, for example, directly below the descending pipe 83.

[0067] Furthermore, in the above-described embodiment, the curved pipeline 82 is a mountain-shaped pipeline consisting of an ascending curved portion 821 and a descending curved portion 822, but it may also be a pipeline that has the ascending curved portion 821 and the descending curved portion 822 as well as other portions.

[0068] Further advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0069] 1 flush toilet 2 Toilet body 5 Bowl section 8 Drain Trap 81 Ascending Pipe 82 Bent pipe 821 Ascending Bend 821a Upper inner surface 822 Downward bend 822a Upper inner surface 83 Descending pipe 84 Bulge 85 Protrusion 9 Outlet 20 Z outlet

Claims

1. A flush toilet that cleans the toilet body with flush water, The toilet body is a bowl portion for receiving waste; a drain trap connected to a lower portion of the bowl portion; A jet water outlet that sprays flush water from the front of the drain trap toward the drain trap; a drain outlet connected to the drain trap for discharging waste from the toilet body; Equipped with The drain trap is an uprising pipe connected to the bowl portion; a bent pipe connected to the ascending pipe, the bent pipe having an ascending bent portion that ascends toward the rear and a descending bent portion that descends toward the rear from the ascending bent portion; a descending pipe line connected to the bent pipe line; Equipped with The drain trap is a bulging portion that forms a space bulging rearward downstream of the bent apex of the bent pipe and that continues to the discharge port; the descending pipe has a protruding portion that protrudes rearward so as to be continuous with the descending bent portion and that continues to the discharge port, A flush toilet characterized in that the protrusion protrudes so as to extend horizontally rearward from the upper inner circumferential surface, which is the inner surface of the upper half of the descending pipe, and protrudes rearward from the height of the vertical center position at the bent apex of the curved pipe.

2. 2. The flush toilet according to claim 1, wherein the protrusion is formed only on the rear side of the descending pipe.

3. 3. The flush toilet according to claim 1 or 2, wherein the lateral width of the protruding portion is approximately the same as the lateral width of the upward bent portion.

4. the curved pipeline is configured with the ascending curved section that ascends toward the rear and the descending curved section that descends from the ascending curved section toward the rear, The flush toilet according to any one of claims 1 to 3, characterized in that, in a side view, the curvature of the upper inner circumferential surface, which is the inner surface of the upper half of the downward bent portion, is smaller than the curvature of the upper inner circumferential surface, which is the inner surface of the upper half of the upward bent portion.

5. The flush toilet according to claim 4, characterized in that the distance between the upper end of the upper inner circumferential surface of the downward bent portion in the flow path cross section and the lower end of the lower inner circumferential surface, which is the inner surface of the lower half of the downward bent portion, increases toward the downstream side in a side view.

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