JP6716099B2 - Flush toilet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flush toilet flushed with flush water supplied from a flush water source to discharge waste.

Conventionally, as a flush toilet flushed with flush water supplied from a flush water source to discharge dirt, for example, as described in Patent Document 1, the inner peripheral surface of the rim portion of the bowl portion of the toilet body is In order to prevent the urine from staying in the connecting portion that connects the standing wall portion and the waste receiving surface to be formed, particularly in the connecting portions near the left and right central portions of the front area of the bowl portion where urine is likely to hit, It is known that the radius of curvature in the up-down direction becomes maximum at the left-right center of the front region of the bowl portion and gradually decreases toward the left-right sides.

JP, 2016-41879, A

However, in the conventional flush toilet described in Patent Document 1 described above, since the inner peripheral side of the rim portion of the bowl portion has no edge, flush water and urine swirled and swirled into the bowl portion There is a problem that it may jump out of the department.
Further, in the above-mentioned conventional flush toilet, since there is no boundary between the standing wall portion area in the bowl portion and the swirl area where the wash water swirls, there is no shelf, etc., especially with the change of the vertical radius of curvature of the connecting portion. There is a problem that the swirling water may swell toward the standing wall portion and jump out to the outside of the bowl portion, or the swirling water may fall around the bowl portion without being able to complete one round, and cleaning may be insufficient.

The present invention has been made in order to solve the above-mentioned problems, and the wash water flowing on the shelf of the bowl does not easily swell toward the rim side, and the wash water can be swirled smoothly, and urine can be removed from the rim. It is an object of the present invention to provide a flush toilet that can prevent running up along the inner peripheral surface of the bowl and jumping out of the bowl.

The present invention is a flush toilet flushed with wash water supplied from a wash water source to discharge dirt, including a bowl-shaped waste receiving surface and a rim portion formed at an upper edge of the waste receiving surface. A bowl portion provided with, a drainage channel connected below the bowl portion for discharging dirt, a rim spouting portion provided in the rim portion for spouting wash water into the bowl portion to form a swirl flow, The bowl portion is further formed in the circumferential direction from the rim water discharge portion between the upper edge portion of the waste receiving surface and the lower end portion of the rim portion, and the wash water discharged from the rim water discharge portion is circumferentially formed. A leading portion is provided, and a connecting portion that connects the outer edge portion of the shelf portion and the lower end portion of the rim portion with a curved surface is provided, and the connecting portion has a vertical curvature radius of the curved surface of the bowl portion. It is set to be almost constant from the front part to the left and right sides, and the shelf part has an inclined surface that inclines downward from the inside to the inside of the bowl part. The inclination angle of this inclined surface is the left and right sides of the bowl part. It is a flush toilet set so that it becomes larger as it is positioned forward from both sides.

In the present invention thus configured, the wash water spouted from the rim spouting part forms a swirling flow (swirling flow) that is guided in the circumferential direction of the bowl part by flowing along the shelf part. .. At this time, regarding the connecting portion that connects the outer edge portion of the shelf portion of the bowl portion and the lower end portion of the rim portion with a curved surface, the radius of curvature of the curved surface is substantially constant from the front portion of the bowl portion to both left and right sides. By being set, the outer edge of the shelf of the bowl and the lower end of the rim can be connected with a relatively small radius of curvature. Further, the shelf portion is provided with an inclined surface that inclines downward from the inside to the inside of the bowl portion, and the inclination angle of this inclined surface is set to increase as it is located from the left and right sides of the bowl portion to the front. .. Therefore, the cleaning water flowing on the shelf of the bowl hardly bulges toward the rim, and the cleaning water can be swirled smoothly. Therefore, it is possible to prevent the wash water from jumping out of the bowl portion, or it is possible to prevent the wash water from flowing into the bowl portion without being swirled sufficiently.
Further, for example, in the front of the bowl where urine is likely to collide, even when the urine collides with the connecting portion of the bowl or the like, the inclination angle of the inclined surface of the shelf is set to be large in front of the bowl. Since the urine does not easily stay in the bowl and can flow down inside the bowl, it is possible to effectively prevent urine from running up the standing wall in front of the bowl and jumping out of the bowl. it can.

In the present invention, preferably, the rim portion forms an upright wall surface on which an inner peripheral surface of the rim portion rises, and the upright wall surface forms an upper side wall surface and an upper side wall surface of the inner peripheral surface of the rim portion, respectively. And a lower standing wall surface, and the radius of curvature of the lower standing wall surface in the up-down direction is set so as to become smaller from the left and right sides of the bowl portion toward the front.

In the present invention thus configured, the standing wall surface includes the upper standing wall surface and the lower standing wall surface forming the upper area and the lower area of the inner peripheral surface of the rim portion, respectively, and the curvature of the lower standing wall surface. The radius is set to decrease from the left and right sides of the bowl toward the front, so that the wash water that flows on the shelf of the bowl does not easily swell to the rim side, making it more reliable and smooth. Can be turned to.
In addition, since the radius of curvature of the lower standing wall of the front wall of the bowl where the urine is prone to collide is set to be small, urine moves upward from the lower wall of the standing wall in front of the bowl. It is possible to more effectively suppress the running up of the standing wall surface and the jumping out of the bowl portion.

In the present invention, preferably, the height of the standing wall surface is set so as to become higher as it is located forward from both left and right sides of the bowl portion.

In the present invention thus configured, the height of the vertical wall surface is set to increase from the left and right sides of the bowl portion toward the front, so that the cleaning water flowing on the shelf portion of the bowl portion is Further, it is difficult to swell toward the rim side, and the wash water can be swung more smoothly.
In addition, since the height of the standing wall in front of the bowl where the urine is likely to collide is set to be high, it is possible for urine to run up the standing wall in front of the bowl and jump out of the bowl. It can be suppressed more effectively.

According to the flush toilet of the present invention, the wash water flowing on the shelf of the bowl hardly swells to the rim side, and the wash water can be swirled smoothly, and the urine can flow along the inner peripheral surface of the rim. It is possible to suppress running up and jumping out of the bowl portion.

FIG. 3 is a central side sectional view of a toilet body of the flush toilet according to the embodiment of the present invention. 1 is a plan view of a toilet body of a flush toilet according to an embodiment of the present invention. The perspective view which looked at the toilet body of the flush toilet according to one embodiment of the present invention from diagonally back. Sectional drawing which followed the AA line of FIG. Sectional drawing which followed the BB line of FIG. Sectional drawing which followed CC line of FIG. Sectional drawing which followed the DD line of FIG.

Hereinafter, a flush toilet according to an embodiment of the present invention will be described with reference to the drawings.
First, FIG. 1 is a central side sectional view of a toilet body of a flush toilet according to an embodiment of the present invention, and FIG. 2 is a plan view of a toilet body of a flush toilet according to an embodiment of the present invention. FIG. 3 is a perspective view of the toilet body of the flush toilet according to the embodiment of the present invention as seen obliquely from the rear.

As shown in FIGS. 1 to 3, a flush toilet 1 according to an embodiment of the present invention includes a toilet body 2 made of earthenware.
Here, in the flush toilet 1 of the present embodiment shown in FIGS. 1 to 3, the toilet seat and the toilet lid are provided on the upper surface of the toilet body 2, and the user's local area is washed behind them. Functional units such as a sanitary cleaning unit and a water supply system functional unit that are involved in the function of supplying water to the toilet body 2 are provided, but these are not shown and their explanations are omitted.

As shown in FIGS. 1 to 3, the toilet body 2 includes a bowl-shaped waste receiving surface 4, a shelf 6 formed at an upper edge of the waste receiving surface 4, and an outer edge of the shelf 6. The bowl portion 10 includes a rim portion 8 formed so as to rise from the portion.
Further, as shown in FIG. 1, the toilet body 2 is provided with a drain trap pipe 12 which is a drainage passage to which an inlet portion 12a is connected below the bowl portion 10 and which discharges the waste in the bowl portion 10. ..
Here, in the flush toilet 1 according to the first embodiment of the present invention shown in FIGS. 1 and 2, the horizontal center axis of the bowl portion 10 of the toilet body 2 in the plan view is indicated by “X”, and the horizontal axis is indicated by “X”. The central axis line in the front-rear direction is indicated by “Y”, and the central axis line in the vertical direction passing through the center O of the bowl portion 10 is indicated by “Z”.
Further, as shown in FIG. 2, the front, rear, left, and right directions of the flush toilet 1 are shown as “front”, “rear”, “left”, and “right”, respectively.
Then, as shown in FIGS. 1 and 2, with respect to the center O of the bowl portion 10 of the flush toilet 1, the horizontal center axis X in the horizontal direction, and the vertical center axis Z, the front side and the rear side, respectively. The areas are defined as "front side area F" and "rear side area B".
Further, as shown in FIG. 2, with respect to the center O of the bowl portion 10 of the flush toilet 1 and the central axis line Y in the horizontal front-rear direction, the left side area L is the left side area and the right side area when viewed from the front. , "Right side region R", respectively.

Next, as shown in FIGS. 1 to 3, the left and right rim portions 8 in the front side region F of the bowl portion 10, that is, the front side region of the bowl portion 10 when viewed from the front of the toilet body 2. On the inner peripheral side of the rim portion 8 in the right side region R in F, a single rim spouting port that functions as a part of the rim spouting portion that spouts cleaning water backward into the bowl portion 10 to form a swirling flow. 14 is formed. That is, the single rim water discharge port 14 is the only water discharge port provided in a part of the front side region F and the right side region R in the entire inner circumference side of the rim portion 8.
Further, a rim water passage (not shown) on the upstream side of the rim water discharge port 14 is formed inside the rim portion 8. The upstream side of this rim water passage (not shown) is a water conduit (see the figure). It is connected to a water supply (not shown) or the like, which is a source of washing water, via a not shown) or the like.
Further, the shelf 6 of the bowl 10 is formed in the circumferential direction on the downstream side from the rim spout 14, and the washing water spouted from the rim spout 14 toward the rear (rim spout) is stored in the shelf 6. It is designed to be guided circumferentially along the top.

Further, as shown in FIG. 1, a jet spout 16 is formed at the bottom of the bowl 10 so as to be directed to the inlet 12 a of the drain trap pipeline 12, and the jet spout 16 also supplies water. Water discharge (jet water discharge) is performed from a system function unit (not shown).
In the flush toilet 1 according to the present embodiment, the rim spouting by the rim spouting port 14 is performed using the water supply pressure of the tap water, and the pressurizing pump (not shown) is controlled for the jet spouting by the jet spouting port 16. Thus, the form of a so-called hybrid type flush toilet for supplying the wash water in the water storage tank (not shown) will be described, but the present invention is not limited to such a form and can be applied to other forms. Further, the jet water spouting by the jet water spouting port 16 may be omitted.

Next, with reference to FIGS. 1 to 7, details of a portion from the upper edge portion of the waste receiving surface 4 of the bowl portion 10 of the flush toilet 1 according to the first embodiment of the present invention to the rim portion 8 will be described. ..
First, FIG. 4 is a cross-sectional view taken along the line AA of FIG. 2, and is a cross-sectional view of a portion from the upper edge portion of the waste receiving surface 4 of the bowl portion 10 to the rim portion 8.
Next, FIG. 5 is a cross-sectional view taken along the line BB of FIG. 2, and centering the center O of the bowl portion 10 from the cross-section taken along the line AA of the toilet body 2 in plan view shown in FIG. It is sectional drawing of the front left side area|region of the bowl part 10 which shifted|deviated 30 degrees clockwise in the circumferential direction.
6 is a cross-sectional view taken along the line CC of FIG. 2, centering on the center O of the bowl portion 10 from the cross-section taken along the line AA of the toilet body 2 in plan view shown in FIG. It is sectional drawing of the front left side area|region of the bowl part 10 which shifted|deviated 60 degrees clockwise in the circumferential direction.
Further, FIG. 7 is a cross-sectional view taken along the line D-D of FIG. 2, centering on the center O of the bowl portion 10 from the cross-section taken along the line AA of the toilet body 2 in plan view shown in FIG. It is sectional drawing of the front left side area|region of the bowl part 10 which shifted|deviated 90 degrees in the clockwise direction of the circumferential direction.
Here, in the present embodiment, 30°, 60°, and 90 counterclockwise in the circumferential direction around the center O of the bowl portion 10 from the cross section taken along the line AA of the toilet body 2 in plan view shown in FIG. 2. The cross-sectional views of the front right region of the bowl portion 10 that are shifted from each other are left-right symmetric with the cross-sectional views of the front left region of the bowl portion 10 shown in FIGS.

First, as shown in FIGS. 4 to 7, the bowl portion 10 includes a connecting portion 18 that connects the outer edge portion 6a of the shelf portion 6 and the lower end portion 8a of the rim portion 8 with a curved surface R1. The radius of curvature ρ1 of the connecting portion 18 in the vertical direction in the elevation view of the curved surface R1 is set to be substantially constant from the front portion of the bowl portion 10 to both left and right sides. As a result, the wash water flowing on the shelf 6 of the bowl 10 does not swell toward the rim portion 8 and can be swirled smoothly.
The "substantially constant" radius of curvature ρ1 referred to here is not only completely constant, but also suppresses the swelling of the cleaning water flowing on the shelf 6 of the bowl 10 toward the rim portion 8 to smooth the cleaning water. It can also be turned to, and includes approximately constant.
Here, the curvature radius ρ1 of the curved surface R1 of the connecting portion 18 in the vertical direction is preferably set to be substantially constant at 3 mm to 15 mm, and more preferably set to be substantially constant at 5 mm to 10 mm.

Next, as shown in FIGS. 4 to 7, the rim portion 8 forms a standing wall surface 20 on which the inner peripheral surface thereof rises.
Further, as shown in FIGS. 4 to 7, with respect to the heights W1 to W4 of the standing wall surface 20, from the lower end portion 8a of the rim portion 8 which coincides with the upper end portion 18b of the connecting portion 18 to the upper surface 8b of the rim portion 8. It corresponds to the height, and the heights W1 to W4 of the standing wall surface 20 are set to be higher as they are located forward from both left and right sides of the bowl portion 10 (W1>W2>W3>W4).
Here, the height W1 of the standing wall surface 20 shown in FIG. 4 is preferably set to, for example, 30 mm to 85 mm, more preferably 50 mm to 75 mm.
Further, the height W2 of the standing wall surface 20 shown in FIG. 5 is preferably set to, for example, 28.5 mm to 82 mm, and more preferably set to 48.5 mm to 72 mm.
Further, the height W3 of the standing wall surface 20 shown in FIG. 6 is preferably set to, for example, 26.5 mm to 78 mm, and more preferably set to 46.5 mm to 68 mm.
Moreover, about height W4 of the standing wall surface 20 shown in FIG. 7, it is 25 mm-75, for example.
It is preferably set to mm, and more preferably set to 45 mm to 65 mm.
In addition, in FIGS. 4 to 7, the respective heights H1 to H4 of the lower end portion 18a of the connecting portion 18 which coincides with the outer edge portion 6a of the shelf portion 6 are changed according to the height of the standing wall surface 20. Since the height of the connecting portion 18 increases from the front portion of the bowl portion 10 to the left and right sides (H1<H2<H3<H4), the connecting portion 18 has a height that increases as it is located from the front portion of the bowl portion 10 to the left and right sides. The positions P1 to P4 are set.
In addition, in the present embodiment, the heights W1 to W4 of the standing wall surface 20 are set so as to become higher from the left and right sides of the bowl portion 10 toward the front, but the present invention is not limited to such a form. Instead, for example, the height of the standing wall surface may be substantially constant.

Next, as shown in FIGS. 4 to 7, the standing wall surface 20 includes an upper standing wall surface 20a and a lower standing wall surface 20b that form an upper area A1 and a lower area A2 of the inner peripheral surface of the rim portion 8, respectively. Therefore, the radii of curvature γ1 to γ4 of the lower standing wall surface 20b are set so as to become smaller from the left and right sides of the bowl portion 10 toward the front (γ1<γ2<γ3<γ4).
Here, the vertical curvature radius γ1 of the lower standing wall surface 20b shown in FIG. 4 is preferably set to 30 mm to 300 mm, more preferably 80 mm to 120 mm, for example.
Further, the vertical radius of curvature γ2 of the lower standing wall surface 20b shown in FIG. 5 is preferably set to 40 mm to 400 mm, and more preferably set to 100 mm to 140 mm, for example.
Further, the vertical curvature radius γ3 of the lower standing wall surface 20b shown in FIG. 6 is preferably set to, for example, 50 mm to 500 mm, and more preferably set to 120 mm to 160 mm.
Further, the radius of curvature γ4 in the vertical direction of the lower standing wall surface 20b shown in FIG. 7 is preferably set to, for example, 300 mm or more, and more preferably set to 300 mm to 3000 mm.
In addition, in the flush toilet 1 of this embodiment shown in FIGS. 4 to 7, the upper standing wall surface 20a is inclined inward from the lower end (upper end of the lower standing wall surface 20b) toward the inside of the bowl portion 10. However, the present invention is not limited to such a configuration, and the upper standing wall surface may be inclined toward the outside of the bowl portion 10 or the upper standing wall surface may rise in the vertical direction.

Next, as shown in FIGS. 1 and 4 to 7, the shelf portion 6 includes inclined surfaces B1 to B4 that are inclined downward from the inside to the inside of the bowl portion 10. The inclination angles α1 to α4 of the inclined surfaces B1 to B4 are set so as to increase as they are located forward from the left and right sides of the bowl portion 10 (α1>α2>α3>α4).
Here, the inclination angle α1 of the inclined surface B1 shown in FIG. 4 is preferably set to, for example, 5° to 35°, more preferably 10° to 20°.
The inclination angle α2 of the inclined surface B2 shown in FIG. 5 is preferably set to 3.5° to 30°, more preferably 8° to 15°, for example.
Further, the inclination angle α3 of the inclined surface B3 shown in FIG. 6 is preferably set to 2.5° to 20°, more preferably 5° to 10°, for example.
The inclination angle α4 of the inclined surface B4 shown in FIG. 7 is preferably set to 1° to 10°, more preferably 2° to 7°.

Further, in the present embodiment, as shown in FIGS. 2 and 3, in the right side region R and the rear side region B in the bowl portion 10, the inner peripheral wall of the rim portion 8 formed on the downstream side of the rim spout 14 ( The curvature (1/r) of the upright wall surface 20) changes from small to large according to the distance from the rim spout 14 to the downstream side in the circumferential direction in the plan view (in other words, the radius of curvature r is large). The curved portion 22 forms a curved surface.
That is, with respect to the curved surface shape of the bent portion 22 in the plan view shown in FIG. 2, the curvature (1/r) thereof changes from small to large at a constant ratio (in other words, the radius of curvature r is constant from large to small. It is formed by a relaxation curve C1 such as a clothoid curve (which changes in proportion).
In addition, when it is desired to further enhance the cleaning of the rear side region B in the bowl portion 10 in which dirt is likely to adhere and which is difficult to clean, the curved shape of the curved portion 22 in the plan view shown in FIG. 2 is not relaxed. It may be set to a curved line, and the curved portion forming such a non-relaxed curve forms a flow for dropping the cleaning water spouted from the rim spouting port 14 into the rear side region B in the bowl portion 10 to form a bowl. You may make it further wash the backside area|region B in the part 10.

Next, the operation of the flush toilet 1 according to the above-described embodiment of the present invention will be described.
First, according to the flush toilet 1 according to the embodiment of the present invention, the flush water spouted from the rim spout 14 is guided along the shelf 6 and guided in the circumferential direction of the bowl 10 to swirl. To form a flow (swirl flow). At this time, regarding the connecting portion 18 that connects the outer edge portion 6a of the shelf portion 6 of the bowl portion 10 and the lower end portion 8a of the rim portion 8 with the curved surface R1, the radius of curvature of the curved surface R1 in the vertical direction in an elevation view. Since ρ1 is set to be substantially constant from the front portion of the bowl portion 10 to the left and right sides, the space between the outer edge portion 6a of the shelf portion 6 of the bowl portion 10 and the lower end portion a of the rim portion 8 is relatively small. Connections can be made with a radius of curvature ρ1. Further, the shelf portion 6 is provided with inclined surfaces B1 to B4 that are inclined downward from the inside to the inside of the bowl portion 10. The inclination angles α1 to α4 of the inclined surfaces B1 to B4 are from both left and right sides of the bowl portion 10. It is set so that it becomes larger as it is located forward (α1>α2>α3>α4).
Therefore, the wash water flowing on the shelf 6 of the bowl 10 is unlikely to swell toward the rim portion 8 and the wash water can be swirled smoothly. Therefore, it is possible to prevent the wash water from jumping out of the bowl portion 10, or it is possible to prevent the wash water from flowing into the bowl portion 10 without being swirled sufficiently.
Further, for example, even when urine collides with the connecting portion 18 or the like of the bowl portion 10 in front of the bowl portion 10 where urine is likely to collide, the inclination angle α1 of the inclined surface B1 of the shelf portion 6 is large in front of the bowl portion. By setting so that the urine does not easily stay and can flow down to the inside of the bowl portion 10, the urine runs up the standing wall surface 20 in front of the bowl portion 19 to the outside of the bowl portion 10. It is possible to effectively suppress jumping out.

Next, according to the flush toilet 1 according to the present embodiment, the standing wall surface 20 on which the inner peripheral surface of the rim portion 8 stands is formed, and the heights W1 to W4 (see FIGS. 4 to 7) of the standing wall surface 20 are set. It is set so that it becomes higher from both the left and right sides of the bowl portion 10 toward the front (W1>W2>W3>W4), so that the cleaning water flowing on the shelf portion 6 of the bowl portion 10 is further on the rim portion 8 side. It is difficult to swell, and wash water can be swirled more smoothly.
Further, since the height W1 of the standing wall surface 20 in front of the bowl portion 10 where urine is likely to collide is set to be high, the urine runs up the standing wall surface 20 in front of the bowl portion 10 and the bowl portion 10 Can be more effectively suppressed from jumping outside.

Further, according to the flush toilet 1 according to the present embodiment, the standing wall surface 20 includes the upper standing wall surface 20a and the lower standing wall surface 20b forming the upper area A1 and the lower area A2 of the inner peripheral surface of the rim portion 8, respectively. The vertical radii of curvature γ1 to γ4 (see FIGS. 4 to 7) of the lower standing wall surface 20b are set to be smaller as they are located in front of the left and right sides of the bowl portion 10 (γ1<γ2). By <γ3<γ4), the wash water flowing on the shelf 6 of the bowl 10 is less likely to swell toward the rim 8 side, and the wash water can be swirled more smoothly.
Further, since the radius of curvature γ1 of the lower standing wall surface 20b of the standing wall surface 20 in front of the bowl portion 10 where urine is likely to collide is set to be particularly small, urine is generated on the standing wall surface 20 in front of the bowl portion 10. It is possible to more effectively suppress the running up of the upper standing wall surface 20a from the lower standing wall surface 20b to the outside of the bowl portion.

1 Rinse Toilet 2 Toilet Main Body 4 Soil Receiving Surface 6 Shelf 6a Outer Edge of Shelf 8 Rim 8a Rim Lower 8b Rim Top 10 Bowl 12 Drain Trap Pipe 12a Inlet 14 Rim Spout 16 Jet spout 18 Connection part 18a Lower end part 18b of connection part Upper end part 20 of connection part Vertical wall surface 22 Bent part

Claims (3)

A flush toilet flushed with flush water supplied from a flush water source to discharge dirt.
A bowl portion provided with a bowl-shaped waste receiving surface and a rim portion formed on an upper edge portion of the waste receiving surface;
A drainage channel that is connected to the lower part of this bowl section and discharges filth,
A rim water spouting part which is provided in the rim part and spouts wash water into the bowl part to form a swirling flow;
The bowl portion is further circumferentially formed from the rim spouting portion between the upper edge portion of the waste receiving surface and the lower end portion of the rim portion, and the washing water spouted from the rim spouting portion in the circumferential direction. And a connecting portion that connects the outer edge portion of the shelf portion and the lower end portion of the rim portion with a curved surface,
In the connecting portion, the radius of curvature of the curved surface in the vertical direction is set to be substantially constant from the front portion of the bowl portion to the left and right sides,
The shelf portion has an inclined surface that inclines downward from the inside to the inside of the bowl portion, and the inclination angle of the inclined surface is set so as to increase as it is positioned from the left and right sides of the bowl portion to the front. A flush toilet that has been used. The rim portion forms a standing wall surface on which the inner peripheral surface rises, and the standing wall surface includes an upper standing wall surface and a lower standing wall surface that respectively form an upper region and a lower region of the inner peripheral surface of the rim portion. 2. The flush toilet according to claim 1, wherein the vertical radius of curvature of the lower standing wall is set so as to become smaller from the left and right sides of the bowl portion toward the front. 3. The flush toilet according to claim 2, wherein the height of the standing wall surface is set so as to increase from the left and right sides of the bowl portion toward the front.

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