Water-washable toilet

Abstract

To provide a one-piece flush toilet that allows for the integral formation of the flushing water tank while suppressing deformation during the manufacturing process before firing the ceramic. [Solution] The present invention relates to a one-piece flush toilet (1) in which the toilet bowl and the flushing water tank are integrally formed, comprising a toilet bowl (2) having a bowl portion (2a) and a drain trap pipe (2b) extending from the lower part of the bowl portion, and a flushing water tank portion (4) formed to rise upward from the upper surface (2e) and rear of the toilet bowl portion, wherein the upper surface of the toilet bowl portion and the front surface (4b) of the flushing water tank portion are connected by a connecting curved surface (6), and the radius of curvature of the vertical cross-section obtained by cutting this connecting curved surface with a vertical plane extending in the front-rear direction of the toilet bowl portion is small at the center in the width direction of the toilet bowl portion and gradually increases toward both ends in the width direction of the toilet bowl portion.

Description

[Technical Field]

[0001] The present invention relates to a flush toilet, and more particularly to a one-piece flush toilet in which the toilet bowl and the flushing water tank are formed as a single unit. [Background technology]

[0002] Japanese Patent Publication No. 2006-104936 (Patent Document 1) describes a flush toilet. This flush toilet has a bowl section, and a flush water tank for cleaning this bowl section is provided behind the bowl section. In other words, the flush toilet described in Patent Document 1 is a so-called one-piece type flush toilet in which the flush water tank is integrally provided so as to rise from the top surface of the flush toilet, behind the bowl section. Such a one-piece type flush toilet has the advantage that the bowl section, drain trap pipe, flush water tank, etc. can be constructed integrally from ceramic, thus simplifying the overall structure of the flush toilet. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2006-104936 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, one-piece flush toilets, such as those described in Patent Document 1, have large components made of ceramic. As a result, there is a problem that the flush toilet is prone to deformation due to its own weight during the manufacturing process before the ceramic is fired. In particular, in one-piece flush toilets, a large flush water tank is integrally formed on the upper rear surface of the toilet bowl, so the upper rear surface of the toilet bowl that supports the flush water tank is prone to deformation during the manufacturing process.

[0005] Therefore, an object of the present invention is to provide a one-piece type flush toilet that can suppress deformation in the manufacturing process before firing the pottery while integrally forming the washing water tank.

Means for Solving the Problems

[0006] In order to solve the above-described problems, the present invention is a one-piece type flush toilet in which a toilet bowl and a washing water tank are integrally formed, and includes a toilet bowl part having a bowl part and a drain trap pipe extending from the lower part of the bowl part, and a washing water tank part formed so as to rise upward from the upper surface and the rear part of the toilet bowl part. The upper surface of the toilet bowl part and the front surface of the washing water tank part are connected by a connecting curved surface, and the radius of curvature of the vertical cross-section obtained by cutting this connecting curved surface with a vertical plane extending in the front-rear direction of the toilet bowl part is small at the center in the width direction of the toilet bowl part and gradually increases toward both ends in the width direction of the toilet bowl part.

[0007] According to the present invention configured as described above, the connecting curved surface connecting the upper surface of the toilet bowl part and the front surface of the washing water tank part is configured such that the radius of curvature in the vertical cross-section is small at the center in the width direction of the toilet bowl part and gradually increases toward both ends in the width direction of the toilet bowl part. For this reason, the rear part of the upper surface of the toilet bowl part that supports the washing water tank part is supported from above by the connecting curved surface having a large radius of curvature at both ends thereof, so that it is possible to suppress deformation so as to sag in the manufacturing process before firing.

[0008] In the present invention, preferably, the vertical cross-section of the connecting curved surface is configured such that the radius of curvature of the lower part connecting to the upper surface of the toilet bowl part is larger than the radius of curvature of the upper part connecting to the front surface of the washing water tank part.

[0009] According to the present invention configured as described above, in the vertical cross-section, since the radius of curvature of the lower part of the connecting curved surface is larger than the radius of curvature of the upper part, even when the radius of curvature of the connecting curved surface is set large, it is not necessary to greatly retreat the washing water tank part, and the front-rear dimension of the flush toilet can be made compact.

[0010] In the present invention, preferably, for the vertical cross-section of the connecting curved surface, the value obtained by dividing the radius of curvature at the lower part of the widthwise end of the toilet part by the radius of curvature at the lower part of the widthwise center of the toilet part is larger than the value obtained by dividing the radius of curvature at the upper part of the widthwise end of the toilet part by the radius of curvature at the upper part of the widthwise center of the toilet part.

[0011] According to the present invention configured as described above, for the vertical cross-section of the connecting curved surface, the value obtained by dividing the radius of curvature at the lower part of the widthwise end of the toilet part by the radius of curvature at the lower part of the widthwise center of the toilet part is larger than the value obtained by dividing the radius of curvature at the upper part of the widthwise end of the toilet part by the radius of curvature at the upper part of the widthwise center of the toilet part. Therefore, even when the front surface of the wash water tank part is curved so as to recede at both ends thereof, it is possible to make the dimension in the front-rear direction of the washlet toilet compact while setting a sufficiently large radius of curvature for the connecting curved surface.

[0012] In the present invention, preferably, the radius of curvature of the vertical curved surface connecting the front surface and the side surface of the wash water tank part is larger than the radius of curvature of the horizontal curved surface connecting the upper surface and the side surface of the toilet part, and at the connection part between the vertical curved surface and the horizontal curved surface, the radius of curvature gradually changes.

[0013] According to the present invention configured as described above, since the radius of curvature of the vertical curved surface connecting the front surface and the side surface of the wash water tank part is larger than the radius of curvature of the horizontal curved surface connecting the upper surface and the side surface of the toilet part, it is possible to visually make the user feel that the lateral width of the wash water tank part is smaller, and give the user a neat impression. Also, since the radius of curvature gradually changes at the connection part between the vertical curved surface and the horizontal curved surface, it does not give a sharp impression, and an elegant appearance can be configured.

Advantages of the Invention

[0014] According to the present invention, in a one-piece washlet toilet, it is possible to suppress deformation in the manufacturing process before firing the pottery while integrally forming the wash water tank.

Brief Description of the Drawings

[0015] [Figure 1] This is a perspective view of a flush toilet according to an embodiment of the present invention. [Figure 2] This is a top view of a flush toilet according to an embodiment of the present invention. [Figure 3] This is a side view of a flush toilet according to an embodiment of the present invention. [Figure 4] This figure shows a vertical cross-section in the front-to-back direction at each part of the connecting curved surface that connects the front surface of the flushing water tank and the upper surface of the toilet bowl in a flush toilet according to an embodiment of the present invention. [Figure 5] This figure shows a cross-section of a vertically curved surface, a horizontally curved surface, and their connection point in a flush toilet according to an embodiment of the present invention. [Modes for carrying out the invention]

[0016] Next, a flush toilet according to an embodiment of the present invention will be described with reference to the attached drawings. Figure 1 is a perspective view of a flush toilet according to an embodiment of the present invention. Figure 2 is a top view of a flush toilet according to an embodiment of the present invention. Figure 3 is a side view of a flush toilet according to an embodiment of the present invention.

[0017] As shown in Figure 1, the flush toilet 1 according to an embodiment of the present invention is a one-piece flush toilet in which a toilet bowl 2 equipped with a bowl portion 2a and a flush water tank 4 for storing flush water to wash the bowl portion 2a are integrally constructed from ceramic. In this embodiment, the flush toilet 1 is configured such that by operating a lever handle 4a provided on the side of the flush water tank 4, the flush water stored in the flush water tank 4 is discharged into the bowl portion 2a of the toilet bowl 2, and the bowl portion 2a is washed.

[0018] As shown in Figures 2 and 3, the toilet bowl 2 comprises a bowl portion 2a for receiving waste and a drain trap pipe 2b extending from the bottom of the bowl portion 2a. Furthermore, a rim outlet 2c from which cleaning water is discharged is provided at the upper end of the bowl portion 2a, and a jet outlet 2d from which cleaning water is discharged is provided at the bottom of the bowl portion 2a.

[0019] A portion of the flushing water discharged from the flushing water tank section 4 is discharged from the rim outlet 2c through a water conduit provided inside the toilet bowl section 2. The flushing water discharged from the rim outlet 2c flows down while swirling inside the bowl section 2a, cleaning the waste receiving surface of the bowl section 2a.

[0020] Furthermore, a portion of the flushing water discharged from the flushing water tank section 4 is discharged from the jet outlet 2d through a water conduit provided inside the toilet bowl section 2. The jet outlet 2d is provided at the bottom of the bowl section 2a so as to face the inlet of the drain trap pipe 2b. Therefore, when flushing water is discharged from the jet outlet 2d, the drain trap pipe 2b becomes full, inducing a siphon effect within the drain trap pipe 2b, and the accumulated water and waste in the bowl section 2a are drawn into the drain trap pipe 2b. Although the flush toilet in this embodiment is a siphon jet type flush toilet, the present invention can also be applied to flush toilets that do not have a jet outlet or flush toilets that do not generate a siphon effect.

[0021] The drain trap pipe 2b is a conduit that extends from the bottom of the bowl section 2a toward the rear of the toilet section 2. The drain trap pipe 2b is composed of an upward-sloping pipe that extends diagonally upward from the bottom of the bowl section 2a and a downward-sloping pipe that extends downward from the downstream end of the upward-sloping pipe. The height of the top between the upward-sloping pipe and the downward-sloping pipe determines the water level W of the water accumulated in the bowl section 2a. The water accumulated in the bowl section 2a seals the drain trap pipe 2b. The downstream end of the downward-sloping pipe of the drain trap pipe 2b is connected to a drain pipe (not shown), and flushing water and waste are discharged from the drain trap pipe 2b.

[0022] As shown in Figure 1, the flushing water tank section 4 is integrally formed with the toilet bowl section 2 so as to rise upward from the rear of the upper surface 2e of the toilet bowl section 2. By opening and closing a drain valve (not shown) located inside the flushing water tank section 4, the discharge of flushing water from the flushing water tank section 4 to the toilet bowl section 2 can be switched on and off.

[0023] Furthermore, as shown in Figure 2, the flushing water tank section 4 is formed in a generally box shape, and its width is approximately the same as the width of the rear of the upper surface 2e of the toilet bowl section 2. That is, the flushing water tank section 4 has a front surface 4b that extends in the width direction on the front side of the toilet bowl section 2, side surfaces 4c that extend in the front-rear direction on both sides of this front surface 4b, and a rear surface 4d that extends in the width direction on the rear side of the toilet bowl section 2. Since the width of the flushing water tank section 4 and the width of the rear of the upper surface 2e of the toilet bowl section 2 are approximately the same, the side surfaces 4c of the flushing water tank section 4 and the upper side surfaces 2f (Figure 1) of the toilet bowl section 2 are flush and smoothly connected.

[0024] On the other hand, the front surface 4b of the flushing water tank section 4 rises upward at approximately a right angle from the upper surface 2e of the toilet bowl section 2. The front surface 4b of the flushing water tank section 4 and the upper surface 2e of the toilet bowl section 2 are smoothly connected by a connecting curved surface 6. In this embodiment, the upper surface 2e of the toilet bowl section 2 is configured to be approximately flat, while the front surface 4b of the flushing water tank section 4, as shown in Figure 2, is gently curved so that the center of the width direction of the toilet bowl section 2 protrudes forward when viewed from above. In this embodiment, the front surface 4b of the flushing water tank section 4 and the connecting curved surface 6 are configured symmetrically in the width direction of the toilet bowl section 2.

[0025] Furthermore, as shown in Figure 2, the front surface 4b and each side surface 4c of the flushing water tank section 4 are smoothly connected by a vertically curved surface 8 extending in a substantially vertical direction. Also, as shown in Figure 1, the upper surface 2e and the upper side surface 2f of the toilet bowl section 2 are smoothly connected by a horizontally curved surface 10 extending in a substantially horizontal direction. These vertically curved surface 8 and horizontally curved surface 10 have a substantially arc-shaped cross-section.

[0026] Next, with reference to Figure 4, the shape of the connecting curved surface 6 that connects the front surface 4b of the flushing water tank section 4 and the upper surface 2e of the toilet bowl section 2 will be described in detail. Figure 4 shows vertical cross-sections in the front-rear direction at various points on the connecting curved surface 6. Column A shows the vertical cross-section of the connecting curved surface 6 along line AA in Figure 2, Column B shows the vertical cross-section of the connecting curved surface 6 along line BB in Figure 2, and Column C shows the vertical cross-section of the connecting curved surface 6 along line CC in Figure 2. Specifically, Column A of Figure 4 shows the vertical cross-section of the connecting curved surface 6 at the center of the width direction of the toilet bowl, Column C shows the vertical cross-section of the connecting curved surface 6 at the end of the width direction of the toilet bowl, and Column B shows the vertical cross-section at a position midway between the cross-sections shown in Column A and Column C.

[0027] As shown in Figure 4, the vertical cross-section of the connecting curved surface 6 in the front-rear direction has the smallest radius of curvature in the cross-section shown in column A, and the radius of curvature increases in the order of columns B and C. That is, the radius of curvature of the vertical cross-section obtained by cutting the connecting curved surface 6 with a vertical plane extending in the front-rear direction of the toilet bowl 2 is small at the center of the width direction of the toilet bowl 2 (column A in Figure 4), and gradually increases toward both ends of the width direction of the toilet bowl 2 (in the order of columns B and C in Figure 4).

[0028] In this embodiment, since the radius of curvature at each part of the connecting curved surface 6 is set as described above, the rear part of the upper surface 2e of the toilet bowl 2 that supports the flushing water tank 4 is supported from above at both ends by the connecting curved surface 6 which has a large radius of curvature. That is, stress concentration is less likely to occur in the parts of the connecting curved surface 6 with a large radius of curvature, and the upper surface 2e of the toilet bowl 2 can be firmly supported. As a result, the necessary strength is ensured even before the toilet bowl 2 and the flushing water tank 4 are fired together as a single ceramic unit, and deformation that causes both ends of the upper surface 2e of the toilet bowl 2 to sag can be suppressed.

[0029] Furthermore, as shown in Figure 4, the radius of curvature of the connecting curved surface 6 differs between the lower part connected to the upper surface 2e of the toilet bowl 2 and the upper part connected to the front surface 4b of the flushing water tank 4, with the radius of curvature of the lower part of the connecting curved surface 6 being larger than that of the upper part. That is, as shown in column A of Figure 4, the radius of curvature R of the lower part of the connecting curved surface 6 1dis the upper radius of curvature R 1u is larger than that, and as shown in column B, the lower radius of curvature R 2d is the upper radius of curvature R 2u is larger than that, and as shown in column C, the lower radius of curvature R 3d is the upper radius of curvature R 3u is configured to be larger. Note that although the radius of curvature of the connecting curved surface 6 is different between the upper and lower parts, their average values are small at the center in the width direction of the toilet bowl part 2 and gradually increase toward both ends in the width direction of the toilet bowl part 2 as described above.

[0030] In this embodiment, since the radii of curvature at the upper and lower parts of the connecting curved surface 6 are set as described above, even when the radius of curvature of the connecting curved surface 6 is set large, it is not necessary to greatly retract the washing water tank part 4, and the front-rear dimension of the flush toilet 1 can be made compact. For example, in column A of FIG. 4, the upper radius of curvature R 1u of the connecting curved surface 6 is smaller than the lower radius of curvature R 1d . Here, as shown by the imaginary line in column A of FIG. 4, if the upper radius of curvature R 1u of the connecting curved surface 6 is formed to be the same as the lower radius of curvature R 1d , the front surface 4b of the washing water tank part 4 continuous with the upper part of the connecting curved surface 6 will retract. As a result, if a washing water tank part 4 having the same depth is to be provided, the front-rear dimension of the flush toilet 1 will become large.

[0031] Also, as shown in FIG. 4, the radius of curvature of each part of the connecting curved surface 6 is such that the radius of curvature R 3d at the lower part of the end in the width direction of the toilet bowl part 2 divided by the radius of curvature R 1d at the lower part of the center in the width direction of the toilet bowl part 3d is larger than the value R 3d / R 1d obtained by dividing the radius of curvature R 3u at the upper part of the end in the width direction of the toilet bowl part 2 by the radius of curvature R 1u at the upper part of the center in the width direction of the toilet bowl part 2 That is, in FIG. 4, the connecting curved surface 6 has (R 3u / R 1u is larger than. That is, in FIG. 4, the connecting curved surface 6 has (R 3d / R 1d)>(R 3u / R 1u It is structured such that the relationship ) holds true.

[0032] In this embodiment, the front surface 4b of the cleaning water tank section 4 is curved so that it recedes at both ends (projects forward in the center in the width direction) (Figure 2). And even when the front surface 4b of the cleaning water tank section 4 is configured in this way, the connecting curved surface 6 is (R 3d / R 1d )>(R 3u / R 1u By configuring the system so that the relationship ) holds true, it is possible to set a sufficiently large radius of curvature for the connecting curved surface 6 while making the dimensions of the flush toilet 1 in the front-to-back direction compact.

[0033] Next, with reference to Figure 5, the shapes of the vertical curved surface 8 of the flushing water tank section 4 and the horizontal curved surface 10 of the toilet bowl section 2 will be described in detail. Figure 5 shows cross-sections of the vertical curved surface 8, the horizontal curved surface 10, and their connection point. Column D shows a cross-section along line DD in Figure 3, column E shows a cross-section along line EE in Figure 3, and column F shows a cross-section along line FF in Figure 3. Specifically, column D of Figure 5 shows a cross-section of the vertical curved surface 8 of the flushing water tank section 4, column F shows a cross-section of the horizontal curved surface 10 of the toilet bowl section 2, and column E shows a cross-section at the connection point between the vertical curved surface 8 and the horizontal curved surface 10.

[0034] As described above, the vertical curved surface 8 is a curved surface that connects the front surface 4b and the side surface 4c of the flushing water tank section 4, and is a curved surface that extends in the height direction of the flushing water tank section 4 (Figure 1). In this embodiment, the vertical curved surface 8 is configured with a substantially constant radius of curvature in the height direction of the flushing water tank section 4. On the other hand, the horizontal curved surface 10 is a curved surface that connects the upper surface 2e and the side surface 2f of the toilet bowl section 2, and is a curved surface that extends in the front-rear direction of the toilet bowl section 2. In this embodiment, the horizontal curved surface 10 is configured with a substantially constant radius of curvature in the front-rear direction of the toilet bowl section 2 in the rear half of the toilet bowl section 2. The vertical curved surface 8 extending in the vertical direction and the horizontal curved surface 10 extending in the horizontal direction are smoothly connected at the point where the flushing water tank section 4 rises from the upper surface 2e of the toilet bowl section 2.

[0035] As shown in column D of Figure 5, the vertical curved surface 8 of the washing water tank section 4 has a radius of curvature R. V On the other hand, the horizontal curved surface 10 of the toilet bowl 2 has a radius of curvature R V Smaller radius of curvature R H It is composed of the following. The cross-section of the connection between the vertical curved surface 8 and the horizontal curved surface 10 (the part where the flushing water tank section 4 rises from the upper surface 2e of the toilet section 2) has a radius of curvature R C It is composed of this. This radius of curvature R C The radius of curvature is R H Larger than, radius of curvature R V It is configured to be smaller than that. That is, at the connection between the vertical curved surface 8 and the horizontal curved surface 10, the radius of curvature gradually changes so that these curved surfaces are smoothly connected. In this embodiment, at the connection between the vertical curved surface 8 and the horizontal curved surface 10, the radius of curvature is configured to gradually decrease from the vertical curved surface 8 toward the horizontal curved surface 10.

[0036] Thus, in the flush toilet 1 of this embodiment, the radius of curvature R of the vertical curved surface 8 V The radius of curvature R of a horizontally curved surface H By making it larger than the others, the width of the cleaning water tank section 4 is visually made to appear smaller, giving the user a clean and neat impression. Furthermore, since the radius of curvature gradually changes at the connection point between the vertical curved surface 8 and the horizontal curved surface 10, it does not give the user an angular impression, resulting in an elegant appearance.

[0037] In the flush toilet 1 embodiment of the present invention, the connecting curved surface 6 connecting the upper surface 2e of the toilet bowl 2 and the front surface 4b of the flushing water tank 4 is configured such that the radius of curvature in its vertical cross-section is small at the center of the width direction of the toilet bowl 2 (column A in Figure 4) and gradually increases toward both ends of the width direction of the toilet bowl 2 (column C in Figure 4). Therefore, the rear upper surface of the toilet bowl 2 supporting the flushing water tank 4 is supported from above at both ends by the connecting curved surface 6 having a large radius of curvature, thus preventing deformation that causes sagging during the manufacturing process before firing.

[0038] Furthermore, according to the flush toilet 1 of this embodiment, in the vertical cross-section, the radius of curvature of the lower part of the connecting curved surface 6 is configured to be larger than the radius of curvature of the upper part (R 1d >R 1u , R 2d >R 2u , R 3d >R 3u Therefore, even if the radius of curvature of the connecting curved surface 6 is set to be large, there is no need to move the flushing water tank section 4 far back, and the dimensions of the flush toilet 1 in the front-to-back direction can be made compact.

[0039] Furthermore, according to the flush toilet 1 of this embodiment, the vertical cross-section of the connecting curved surface 6 has a radius of curvature R at the lower part of the widthwise end of the toilet bowl 2. 3d The radius of curvature R at the lower part of the center in the width direction of the toilet bowl. 1d The value obtained by dividing by (R 3d / R 1d ) is the radius of curvature R at the upper part of the widthwise end of the toilet bowl 2. 3u The radius of curvature R at the upper part of the center in the width direction of the toilet bowl 2. 1u The value obtained by dividing by (R 3u / R 1u It is configured to be larger than the ). Therefore, even when the front surface 4b of the flushing water tank section 4 is curved to recede at both ends (Figure 2), the dimensions of the flush toilet 1 in the front-to-back direction can be made compact while setting a sufficiently large radius of curvature for the connecting curved surface 6.

[0040] Furthermore, according to the flush toilet 1 of this embodiment, the radius of curvature R of the vertical curved surface 8 connecting the front surface 4b and the side surface 4c of the flush water tank section 4 V However, the radius of curvature R of the horizontal curved surface 10 connecting the upper surface 2e and the side surface 2f of the toilet bowl 2 H Because it is larger than the other, the width of the cleaning water tank section 4 is visually perceived as smaller, giving the user a clean and neat impression. In addition, since the radius of curvature gradually changes at the connection point between the vertical curved surface 8 and the horizontal curved surface 10 (Figure 5), it does not give an angular impression, and an elegant appearance can be created.

[0041] While embodiments of the present invention have been described above, various modifications can be made to the embodiments described above. In particular, in the embodiments described above, the present invention was applied to a flush toilet in which a rim spout and a jet spout are provided in the bowl portion, and the bowl portion is cleaned by the cleaning water discharged from these spouts. However, the present invention can be applied to any flush toilet with any cleaning method. Furthermore, in the embodiments described above, the entire amount of cleaning water used for cleaning was supplied from the cleaning water tank. However, the present invention can also be applied to a flush toilet in which, for example, some of the cleaning water is supplied directly from the water supply. [Explanation of Symbols]

[0042] 1 flush toilet 2 Toilet bowl 2a Bowl section 2b Drain trap pipe 2c Rim spout 2D Jet Spout 2e Top side 2f side 4. Washing water tank section 4a Lever handle 4b front 4c side 4d rear 6. Connecting curved surface 8. Vertical curved surface 10 Horizontal curved surface

Claims

1. A one-piece flush toilet in which the toilet bowl and the flushing water tank are formed as a single unit, A toilet bowl comprising a bowl section and a drain trap pipe extending from the lower part of the bowl section, This toilet bowl has a flushing water tank section formed to rise upward from the upper and rear surfaces, A flush toilet characterized in that the upper surface of the toilet bowl and the front surface of the flushing water tank are connected by a connecting curved surface, and the radius of curvature of the vertical cross-section obtained by cutting this connecting curved surface with a vertical plane extending in the front-to-back direction of the toilet bowl is small at the center in the width direction of the toilet bowl and gradually increases toward both ends in the width direction of the toilet bowl.

2. The flush toilet according to claim 1, wherein the vertical cross-section of the connecting curved surface is configured such that the lower radius of curvature connecting to the upper surface of the toilet bowl is greater than the upper radius of curvature connecting to the front surface of the flushing water tank.

3. The flush toilet according to claim 2, wherein the vertical cross-section of the connecting curved surface is greater than the value obtained by dividing the radius of curvature at the lower part of the widthwise end of the toilet bowl by the radius of curvature at the lower part of the widthwise center of the toilet bowl by the value obtained by dividing the radius of curvature at the upper part of the widthwise end of the toilet bowl by the radius of curvature at the upper part of the widthwise center of the toilet bowl.

4. The flush toilet according to claim 1, wherein the radius of curvature of the vertical curved surface connecting the front surface of the flush water tank and the side surface of the flush water tank is greater than the radius of curvature of the horizontal curved surface connecting the top surface of the toilet bowl and the side surface of the toilet bowl, and the radius of curvature gradually changes at the connection between the vertical curved surface and the horizontal curved surface.

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