Flush toilet

A flush toilet is capable of suppressing water from splashing from a bowl at a time when water is discharged rearward inside the bowl from one rim spout port portion formed in a rim portion. A rim spout portion of the flush toilet forms a rim water passage where flush water that is supplied flows through, and forms, on a downstream end of the rim water passage, a rim spout port portion that discharges the flush water rearward. The rim spout port portion, which is one in number, is formed in the rim portion, and the rim spout port portion in the linear portion is formed to discharge water rearward in the bowl in a direction extending the linear portion.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit of priority to Japanese Patent Application No. 2021-030148, filed Feb. 26, 2021, the entire content of which is incorporated herein by reference.

BACKGROUND

Technical Field

The present disclosure relates to a flush toilet, and more particularly, to a flush toilet for discharging waste with flush water supplied from a flush water supply source.

Background Art

Conventionally, there is known, as described in Japanese Patent Laid-Open No. 2014-152468, a flush toilet including a first spouting port that is formed a little rearward from a center, on a left side when seen from a front side of a shelf of a bowl, and a second spouting port that is formed on a rear side on a right side when seen from the front side, where the first spouting port and the second spouting port form circulating flows that circulate in the same direction.

Furthermore, as described in Japanese Patent Laid-Open No. 2017-20213, there is known a flush toilet that forms a circulating flow in a bowl by discharging water from three water discharge ports including a water discharge port from a flow channel including a returning portion.

SUMMARY

In contrast to the conventional flush toilets described in Japanese Patent Laid-Open No. 2014-152468 and Japanese Patent Laid-Open No. 2017-20213 mentioned above, consideration is given to flushing of a bowl with water that is discharged from one rearward-facing rim spout port portion. For example, as described in Japanese Patent Laid-Open No. 2017-160671, consideration is given to a flush toilet where water is discharged rearward from a rim spout port portion and a circulating flow is formed in a bowl. However, when a flow for flushing the bowl is to be formed by discharge of water from one rearward-facing rim spout port portion, there is a problem that water tends to splash at a part on a rear side of the bowl where curvature of a curve of a rim portion changes. Furthermore, because it is difficult to form a relatively strong circulating flow in the bowl by one rim spout portion that is formed in the rim portion, there is a problem that flushing performance for the bowl tends to be reduced. Furthermore, also in the case of considering newly forming a bowl that includes linear portions disposed on right and left sides of a rim portion and that includes an arc portion that connects the linear portions, and considering flushing of the bowl with water discharged from one rearward-facing rim spout port portion, there are problems that water tends to splash at a part on a rear side of the bowl where curvature of a curve of the rim portion changes, and that flushing performance for the bowl tends to be reduced.

Accordingly, an embodiment of the disclosure is aimed at providing a flush toilet with which splashing of water from a bowl may be suppressed at a time when water is discharged rearward in the bowl from one rim spout port portion formed in a rim portion.

Therefore, an embodiment of the disclosure is a flush toilet for discharging waste with flush water supplied from a flush water supply source, the flush toilet including a bowl including a water receiving surface that is bowl-shaped, a rim portion that is formed in a top edge of the waste receiving surface, and a shelf surface that is provided along an entire circumference to connect the waste receiving surface and the rim portion. The rim portion includes linear portions that are disposed on right and left sides of the bowl in a top view, arc portions that connect the linear portions on the right and left sides of the bowl at front end portions and rear end portions of the linear portions, and a rim spout portion that discharges flush water supplied from the flush water supply source into the bowl and that forms a circulating flow inside the bowl. The rim spout portion forms a rim water passage where the flush water that is supplied flows through, and forms, on a downstream end of the rim water passage, a rim spout port portion that discharges the flush water rearward, and the rim spout port portion of the rim spout portion, which is one in number, is formed in the rim portion. The rim spout port portion in the linear portion is formed to discharge water rearward in the bowl in a direction extending the linear portion.

According to an embodiment of the disclosure having a configuration as described above, at the bowl where the rim portion includes the linear portions that are disposed on the right and left sides of the bowl in the top view and the arc portions that connect the linear portions on the right and left sides of the bowl at the front end portions and the rear end portions of the linear portions, one rim spout port portion is formed in the rim portion in such a manner as to discharge water at the linear portion, rearward in the bowl in the direction extending the linear portion.

Accordingly, when forming a relatively strong circulating flow in the bowl by one rim spout port portion that is formed in the rim portion, flush water that is discharged from the rim spout port portion may be adjusted to flow, at the linear portion, in the direction extending the linear portion, and splashing of water at a curvature change portion connecting the linear portion and the arc portion on the rear side of the linear portion may be suppressed. Accordingly, with the bowl including the linear portions and the arc portions that are disposed on the rim portion, where the arc portions connect the linear portions, when water is discharged rearward in the bowl from one rim spout port portion that is formed in the rim portion, splashing of water from the bowl may be suppressed.

According to an embodiment of the disclosure, preferably, the rim water passage includes an outer side portion that extends forward inside the rim portion, a curved portion that is curved inward from a downstream end of the outer side portion, and an inner side portion that extends rearward from the curved portion to the rim spout port portion.

According to an embodiment of the disclosure having a configuration as described above, the rim water passage that is curved in a U-turn shape may be formed inside the rim portion by the outer side portion, the curved portion and the inner side portion of the rim water passage. A length of the rim water passage up to the rim spout port portion may be made relatively short and reduction in the force of flush water may be suppressed, and the flush water may be discharged from the rim spout port portion while maintaining a relatively strong force of the flush water, and thus, flushing performance may be further increased for the bowl.

According to an embodiment of the disclosure, preferably, the outer side portion of the rim water passage includes a curved-portion-side linear portion that is connected to the curved portion.

According to an embodiment of the disclosure having a configuration as described above, because the outer side portion of the rim water passage includes the curved-portion-side linear portion that is connected to the curved portion, a pressure loss of the flush water at the outer side portion may be reduced compared to a case where the outer side portion includes a curved portion connected to the curved portion, and thus, flush water with a relatively strong force may be supplied to the rim spout port portion. Furthermore, flush water passing through the rim water passage flows to the curved portion in a state where the flow is adjusted to be linear by the curved-portion-side linear portion, and thus, compared to a case where the flush water flows to the curved portion in a disturbed state, the pressure loss of the flush water at the curved portion may be reduced, and thus, flush water with a relatively strong force may be supplied to the rim spout port portion.

According to an embodiment of the disclosure, preferably, the inner side portion of the rim water passage includes a spout-port-side linear portion that is connected to the rim spout port portion.

According to an embodiment of the disclosure having a configuration as described above, because the inner side portion of the rim water passage includes the spout-port-side linear portion that is connected to the rim spout port portion, a pressure loss of the flush water at the inner side portion may be reduced compared to a case where the inner side portion includes a curved portion connected to the rim spout port portion, and thus, flush water with a relatively strong force may be supplied to the rim spout port portion. Furthermore, flush water passing through the rim water passage is discharged from the rim spout port portion in a state where the flow is adjusted to be linear by the spout-port-side linear portion, and thus, compared to a case where the flush water is discharged from the rim spout port portion in a disturbed state, the flush water may be discharged in a state where the flow is better adjusted, and splashing of water at the curvature change portion may be better suppressed. Furthermore, because the flush water is discharged from the rim spout port portion in a state where the flow is adjusted to be more linear, the pressure loss may be reduced for the flush water that is discharged from the rim spout port portion, and a stronger circulating flow may be formed inside the bowl.

According to an embodiment of the disclosure, preferably, the curved portion of the rim water passage is provided at a position more rearward than a connecting portion between the linear portion and the arc portion on a front side of the linear portion.

According to an embodiment of the disclosure having a configuration as described above, the curved portion is provided at a position more rearward than the connecting portion between the linear portion and the arc portion on the front side of the linear portion. Accordingly, in contrast to a case where the curved portion is formed at a position more forward than the connecting portion between the linear portion and the arc portion on the front side of the linear portion, the curved portion may be curved inside the rim portion on the linear portion side without being curved inside the rim portion on the arc portion side, and the pressure loss at the curved portion may be reduced. Moreover, an external appearance may be suppressed from being impaired due to a width of the rim portion becoming relatively great on the arc portion side because of the curved portion being curved inside the rim portion on the arc portion side, and also, a reduction in a size of the waste receiving surface of the bowl and the like may be suppressed, for example.

According to an embodiment of the disclosure, preferably, the bowl further includes a rim-spout-section water passageway that extends in a rear side of the rim spout port portion, from the rim spout port portion toward a direction extending the linear portion, a ceiling surface of the rim-spout-section water passageway being formed in a manner overhanging from an inner side of the bowl to an outer side, the rim-spout-section water passageway being formed in a manner cutting out the bowl from the inner side of the bowl to the outer side.

According to an embodiment of the disclosure having a configuration as described above, the bowl further includes the rim-spout-section water passageway that extends on the rear side of the rim spout port portion, the rim-spout-section water passageway extending from the rim spout port portion in the direction extending the linear portion, and the ceiling surface of the rim-spout-section water passageway is formed in a manner overhanging from the inner side of the bowl to the outer side, and the rim-spout-section water passageway is formed in a manner cutting out the bowl from the inner side to the outer side. Accordingly, upward splashing of flush water discharged from the rim spout port portion may be suppressed by the ceiling surface, and also, the flow may be adjusted at the rim-spout-section water passageway to be along the direction extending the linear portion, and splashing of water at the curvature change portion that connects the linear portion and the arc portion on the rear side of the linear portion may be better suppressed. Accordingly, with the bowl including the linear portions and the arc portions that are disposed on the rim portion, where the arc portions connect the linear portions, water may be better suppressed from splashing from the bowl at a time when water is discharged rearward inside the bowl from one rim spout port portion formed in the rim portion.

With the flush toilet of an embodiment of the disclosure, splashing of water from the bowl may be suppressed at a time when water is discharged rearward in the bowl from one rim spout port portion formed in the rim portion.

DETAILED DESCRIPTION

Next, a flush toilet according to an embodiment of the present disclosure will be described with reference toFIGS.1to3.

FIG.1is an overall structural diagram of the flush toilet according to the embodiment of the present disclosure. Furthermore,FIG.2is a plan view of the flush toilet according to the embodiment of the present disclosure, andFIG.3is a cross-sectional view taken along a line III-III inFIG.1.

As shown inFIG.1, a flush toilet1according to an embodiment of the present disclosure includes a main water passageway2where flush water that is supplied from a main water supply source W0(a flush water supply source) such as a water system flows through, a toilet main body4made of ceramics, and a flush water supply device6. The flush toilet1discharges waste with flush water supplied from the main water supply source W0.

In the following description about the embodiment of the present disclosure, a description is given taking a side closer to a user using the flush toilet1(a user who is standing in front of the flush toilet1to use the flush toilet1) as a front side, a back side as seen from the user as a rear side, a right side of the flush toilet1as seen from the front side as a right side, and a left side as seen from the front side as a left side.

Next, as shown inFIGS.1and2, the toilet main body4includes a bowl8for receiving waste, a rim portion10that is formed in a top edge of the bowl8, and a water discharge trap pipe12that is a water discharge trap section extending from a bottom portion of the bowl8. Furthermore, although details will be given later, the flush water supply device6is a functional unit that is provided more rearward than the bowl8of the toilet main body4and that enables flush water supplied from the main water passageway2to be supplied to the toilet main body4. More specifically, the functional unit includes a function of controlling discharge and stopping of flush water to the bowl8of the toilet main body4by operating on electric power.

The bowl8includes a bowl-shaped waste receiving surface9, the rim portion10formed in a top edge of the waste receiving surface9, and a shelf surface11that is provided along an entire circumference to connect the waste receiving surface9and the rim portion10. The shelf surface11is formed as a flat surface between the waste receiving surface9and the rim portion10, and is formed as an inward and slightly downward slope. The shelf surface11extends alongside with and approximately in parallel with the rim portion10, on an inner side of the rim portion10. Accordingly, the shelf surface11forms linear portions on inner sides of a right linear portion50aand a left linear portion50bdescribed later, and forms arc portions on inner sides of front and rear arc portions52described later.

Next, as shown inFIGS.2and3, the rim portion10of the bowl8includes a rim spout portion14for forming a circulating flow inside the bowl8by discharging flush water supplied from the flush water supply source into the bowl8. The rim spout portion14is provided in the rim portion10, on one of left and right sides of the bowl8of the toilet main body4(for example, on the right side when the toilet main body4is seen from the front side). Furthermore, the rim spout portion14forms a rim water passage46where supplied flush water flows through, and also forms a rim spout port portion48for discharging the flush water rearward, the rim spout port portion48being formed on a downstream end of the rim water passage46. The rim water passage46forms a rim conduit inside the rim portion10. The rim water passage46has a so-called U-turn shape that extends forward from the rear side of the toilet main body4and then bends rearward, the rim water passage46extending inside the rim portion10, on one of the left and right sides of the toilet main body4(for example, on the right side of the toilet main body4seen from the front side). Furthermore, a rim-side water supply channel2aof the flush water supply device6, of which more later, is connected on an upstream side of the rim water passage46. Flush water that is supplied from the rim-side water supply channel2ato the rim water passage46is discharged into the bowl8, rearward from the rim spout port portion48, and rim spouting is thus performed.

Next, as shown inFIGS.1and2, a jet conduit16is formed extending from an outer surface of the bowl8of the toilet main body4to the bottom portion. A downstream side of the jet conduit16faces an inlet12aof the water discharge trap pipe12at the bottom portion of the bowl8, and a jet spout port16ais provided on a downstream end of the jet conduit16.

Furthermore, a jet-side water supply channel2bof the flush water supply device6, of which more later, is provided on an upstream side of the jet conduit16of the toilet main body4. Flush water that is supplied from the jet-side water supply channel2bto the jet conduit16of the toilet main body4is discharged from the jet spout port16atoward the water discharge trap pipe12, and jet spouting is thus performed.

Now, as shown inFIG.1, an upstream side of the rim-side water supply channel2aof the flush water supply device6is connected to a switching valve18(of which more later) at a branch part B on the main water passageway2. On the other hand, an upstream side of the jet-side water supply channel2bof the flush water supply device6is connected to a pressure pump22(of which more later) of the flush water supply device6provided on a downstream side of a storage tank20of the flush water supply device6, as shown inFIG.1.

Next, the water discharge trap pipe12of the toilet main body4forms a discharge conduit that is connected at a lower part of the bowl8and that is for discharging waste. The water discharge trap pipe12includes the inlet12aprovided at the bottom portion of the bowl8, a trap ascending pipe12bthat ascends from the inlet12a, and a trap descending pipe12cthat descends from the trap ascending pipe12b, and a part between the trap ascending pipe12band the trap descending pipe12cis made a top portion12d. Furthermore, as shown inFIG.1, an outlet12eof the trap descending pipe12cof the water discharge trap pipe12is connected to an inlet of a discharge socket S that is disposed behind and below the toilet main body4. Furthermore, as shown inFIG.1, an outlet of the discharge socket S on the rear side is connected to an inlet of a drain pipe D extending from a wall (not shown) on the rear side of the toilet main body4. Water is accumulated above a coupling portion between the waste receiving surface9and the water discharge trap pipe12. Additionally, in the present example, a construction where water is discharged from the water discharge trap pipe12to the drain pipe D in the wall behind the flush toilet1is described, but construction is not limited to construction in which water is drained through the wall, and a discharge socket for discharging water through a floor may be connected to the discharge water and may discharges water to a drain pipe provided in the floor.

Next, each structure of the flush water supply device6of the flush toilet1according to the present embodiment will be schematically described with reference toFIG.1.

First, as shown inFIG.1, the flush water supply device6includes, from an upstream side to a downstream side of the main water passageway2, a stop cock24, splitter hardware26, a valve unit28, and the switching valve18.

Next, the valve unit28includes a fixed flow valve30, a diaphragm main valve32, and an electromagnetic valve34such as a solenoid valve.

Furthermore, the flush water supply device6includes a controller36. The controller36includes an arithmetic device such as a CPU and a storage device such as a memory embedded therein, and is capable of controlling electrically connected units according to predetermined control programs and the like. In the present embodiment, the controller36is capable of functioning as a controller that controls an opening-closing operation of an on-off valve (the electromagnetic valve34) of the valve unit28, a switching operation of the switching valve18, and a rotational speed, an operation time and the like of the pressure pump22.

Moreover, the fixed flow valve30of the valve unit28is for reducing flush water flowing from the stop cock24on the main water passageway2and through the splitter hardware26to or below a predetermined flow rate.

Additionally, in a construction where the flush toilet1is provided with a private part washing device (not shown), a water supply pipe (not shown) for supplying flush water to the private part washing device (not shown) may also be connected to the splitter hardware26.

Furthermore, at the valve unit28, when an opening operation is performed on the electromagnetic valve34by the controller36, the main valve32is opened, and flush water passing from the fixed flow valve30and through the main valve32is supplied to the switching valve18at the branch part B on the downstream side of the main water passageway2.

The switching valve18is capable of supplying flush water from the main water passageway2to the rim-side water supply channel2aand a tank-side water supply channel2cat a same timing, and a ratio between water supplied to the rim side and water supplied to the tank side may be freely changed.

Next, the flush water supply device6includes a tank device T that enables flush water supplied from the main water passageway2to be supplied to the toilet main body4. The tank device T includes the storage tank20that is coupled to a rear side of the toilet main body4and that is for storing flush water supplied from the main water passageway2, and the pressure pump22for feeding the flush water in the storage tank20to the toilet main body4under pressure.

Furthermore, the rim-side water supply channel2athat communicates with the rim water passage46of the toilet main body4, and the tank-side water supply channel2cthat is connected to the storage tank20are provided on the downstream side of the branch part B on the downstream side of the main water passageway2.

Accordingly, flush water that is supplied from the main water supply source W0to the branch part B of the main water passageway2is used as water to be supplied to at least one of the rim-side water supply channel2ato be supplied to the rim and the tank-side water supply channel2cto be supplied to the tank.

Furthermore, the flush water supply device6includes a pump water supply channel2dthat extends from a downstream side of the tank-side water supply channel2cto the pressure pump22, and the jet-side water supply channel2bthat extends on a downstream side from the pressure pump22.

Accordingly, with the flush toilet1of the present embodiment, flush water that is supplied from the main water passageway2and that is directly supplied under tap water pressure may be supplied from the rim-side water supply channel2aof the flush water supply device6to the rim spout port portion48, via the rim water passage46of the toilet main body4, and water may thus be discharged from the rim spout port portion48(so-called “rim spouting”).

Furthermore, the flush water supplied from the main water passageway2to the flush water supply device6may flow through the tank-side water supply channel2c, the storage tank20, the pump water supply channel2dand the pressure pump22of the flush water supply device6and then be supplied from the jet-side water supply channel2bto the jet spout port16a, via the jet conduit16of the toilet main body4, and water may thus be discharged water from the jet spout port16a(so-called “jet spouting”). That is, the flush toilet1of the present embodiment may function as a so-called hybrid flush toilet1that is capable of using, in combination, rim spouting that uses flush water that is supplied from the main water passageway2and that is directly supplied under tap water pressure, and jet spouting that uses flush water that is from the storage tank20and that is pressurized by the pressure pump22.

Now, an upper float switch38and a lower float switch40are disposed inside the storage tank20. A water level inside the storage tank20may be detected by these float switches38,40.

For example, the upper float switch38is switched on when the water level inside the storage tank20reaches a predetermined water storage level, and the controller36detects an on state of the upper float switch38and causes the electromagnetic valve34to close.

On the other hand, the lower float switch40is switched on when the water level inside the storage tank20falls to a predetermined water level below the predetermined water storage level that is detected by the upper float switch38, and the controller36detects an on state of the lower float switch40and causes the pressure pump22to stop.

Furthermore, the pressure pump22sucks the flush water stored in the storage tank20into the pump water supply channel2dand pressurizing the flush water from the pump water supply channel2dinto the jet-side water supply channel2band discharges the flush water from the jet spout port16a.

With the structures described above, at a time of normal toilet flushing, the controller36detects operation of a toilet flushing switch (not shown) by a user, for example, and causes the electromagnetic valve34, the switching valve18, and the pressure pump22to sequentially operate. Discharge of water from the rim spout port portion48and the jet spout port16ais thus sequentially started, and flush water used to flush the bowl8is drained from the water discharge trap pipe12, together with waste in the bowl8. Furthermore, the controller36opens the electromagnetic valve34after flushing is finished, and the switching valve18is switched to the tank-side water supply channel2cside, and flush water in the main water passageway2is used to refill the storage tank20.

Then, when the water level inside the storage tank20rises and the upper float switch38detects a specified water storage amount, the controller36closes the electromagnetic valve34so that the main valve32closes the main water passageway2, and supply of water is thereby stopped. Moreover, each of the above-described units of the flush water supply device6(functional unit) is provided in a rear function housing unit V0(seeFIG.2) in a region behind the bowl8of the toilet main body4.

Next, a structure of the bowl8of the toilet main body4of the flush toilet1according to the present embodiment is explained with reference toFIGS.1to3.

The rim portion10of the bowl8includes linear portions50that are disposed alongside each other on right and left sides of the bowl8in a top view while extending in approximately same directions, and arc portions52that connect the right and left linear portions50of the bowl8at front end portions and rear end portions of the linear portions50.

The linear portions50of the rim portion10include the right linear portion50aand the left linear portion50b, the right linear portion50aand the left linear portion50bextending linearly in a front-back direction on the right side and the left side, respectively, of the bowl8in the top view. The right linear portion50aand the left linear portion50bare each disposed between a connecting portion62between the arc portion52on the front side and the linear portion50and a connecting portion62between the arc portion52on the rear side and the linear portion50. The connecting portion62forms a curvature change portion that connects the arc portion52that has an arc shape and the linear portion50that has a linear shape. Additionally, the linear portions50extend substantially in parallel to each other on the right and left sides of the bowl8. The linear portions50do not have to be formed alongside each other on the right and left sides of the bowl8while having a same length. Because the linear portions50of the rim portion10are formed to have a linear shape, splashing of water and energy loss caused by flush water on the shelf surface11hitting the linear portions50and the like of the rim portion10may be suppressed, and flush water may be discharged in such a way that a relatively strong flow of flush water may be formed in the bowl8. The linear portions50desirably have a linear shape, but an approximately linear shape that is curved so as not to cause flush water to hit the linear portions50and the like of the rim portion10and to splash is also acceptable.

Furthermore, the linear portions50of the rim portion10include, in a horizontal cross-section at a height around a center of the rim spout portion14as shown inFIG.3, a front right linear portion50cthat extends in the front-back direction at a position more forward than the rim spout port portion48and on an inner side in the toilet main body, and a rear right linear portion50dthat extends in the front-back direction at a position more rearward than the rim spout port portion48and on an outer side in the toilet main body. The rim spout port portion48is provided in a rear region of the toilet main body4on a rear side than a center (a central transversal line E extending in a left-right direction to equally divide the bowl8in the front-back direction) of the toilet main body4.

The front right linear portion50cand the rear right linear portion50dare disposed alongside each other. The front right linear portion50cand the rear right linear portion50dextend substantially in parallel to each other. Because the rim spout port portion48that faces rearward is formed at the right linear portion50a, the front right linear portion50cand the rear right linear portion50dare formed so as to be shifted from each other in a stepwise manner between inner and outer sides. The front right linear portion50cand the rear right linear portion50dare disposed shifted from each other in the front-back direction, and the front right linear portion50cand the rear right linear portion50ddo not have to be formed alongside each other with a same length. The front right linear portion50cand the rear right linear portion50dform the right linear portion50athat extend approximately in the front-back direction. The front right linear portion50cand the rear right linear portion50dextend substantially in parallel to and alongside the left linear portion50b. Furthermore, the front right linear portion50cand the rear right linear portion50dalso extend substantially in parallel to a center cross-section C along the front-back direction of the toilet main body4. Moreover, the front right linear portion50cand the rear right linear portion50dextend substantially in parallel to and alongside each of an outer side portion56and an inner side portion60of the rim water passage46described later.

The arc portion52is defined as a single arc that is defined by approximately one curvature radius. The arc portion52is formed so as to protrude forward between the connecting portion62on the front side of the right linear portion50aand the connecting portion62on the front side of the left linear portion50b. Furthermore, the arc portion52is formed so as to protrude rearward between the connecting portion62on the rear side of the right linear portion50aand the connecting portion62on the rear side of the left linear portion50b. The arc portion52may be defined basically as a single arc that is defined by one curvature radius, but with each of both end portions being defined as a different arc defined by a different curvature radius. In this manner, the arc portion52may be formed as a complex arc, with a part thereof being defined as a different arc that is defined by a different curvature radius. Furthermore, the whole arc portion52may be defined by a plurality of arcs that are defined by a plurality of curvature radii. Furthermore, with respect to the arc portions52, only the arc portion on the front side may be defined as a predetermined arc as described above. Additionally, a length in the front-back direction from the connecting portion62, between the linear portion50and the arc portion52, to a front end (or a rear end) of the arc portion52(a radius of the arc portion52) is greater than a length of the linear portion50in the front-back direction. When the radius of the arc portion52is greater than the length of the linear portion50, a flow of flush water flowing from the linear portion50to the arc portion52changes slowly, and splashing of flush water flowing from the linear portion50to the arc portion52may be suppressed. Moreover, the radius of the arc portion52on the rear side (the length in the front-back direction from the connecting portion62, between the linear portion50and the arc portion52on the rear side, to the rear end of the arc portion52on the rear side) is greater than the radius of the arc portion52on the front side (the length in the front-back direction from the connecting portion62, between the linear portion50and the arc portion52on the front side, to the front end of the arc portion52on the front side), and thus, because a bowl surface is wider on the rear side, user can feel more relaxed at the time of excretion, both when user is excreting at a standing position and at a sitting position.

The rim water passage46includes the outer side portion56that extends inside the rim portion10, toward the front side, a curved portion58that is curved inward from a downstream end of the outer side portion56, and the inner side portion60that extends rearward from the curved portion58to the rim spout port portion48.

The outer side portion56extends from the rear region of the toilet main body4to a front region more forward than the center (the central transversal line E extending in the left-right direction to equally divide the bowl8in the front-back direction) of the toilet main body4. The outer side portion56forms a flow channel that is positioned on an outer side than the inner side portion60. As shown inFIG.5, an outer-side-portion outer side wall56aand an outer-side-portion inner side wall56bof the outer side portion56extend substantially in parallel to and alongside each other, and a gap between the two side walls are assumed to be substantially constant. A ceiling surface and a bottom surface of the outer side portion56are formed substantially in parallel to and alongside each other, and a flow channel cross-sectional area inside the outer side portion56is maintained approximately constant at the outer side portion56. The outer side portion56forms a flow channel that extends linearly in the front-back direction. The outer side portion56includes a curved-portion-side linear portion56cthat is connected to the curved portion58. The curved-portion-side linear portion56cforms a flow channel that extends linearly at least up to the curved portion58. The curved-portion-side linear portion56cmay adjust the flow of flush water just before reaching the curved portion58to be linear.

The curved portion58forms a U-shaped flow channel in the top view to connect the outer side portion56extending from the rear side and the inner side portion60extending toward the rear side. Accordingly, the curved portion58is formed to cause flush water flowing in from the rear side to flow out toward the rear side. The curved portion58is formed at a position more rearward than the connecting portion62between the linear portion50and the arc portion52on the front side of the linear portion50. Accordingly, the curved portion58is formed into a U-turn shape inside the rim portion10that extends linearly. This suppress the U-turn shape of the curved portion58from being deformed inside the rim portion10that is curved, and an increase in a pressure loss may be suppressed. The curved portion58is positioned in the front region more forward than the central transversal line E of the toilet main body4.

As shown inFIG.4, the curved portion58includes a top portion68at a position farthest from an intermediate part66, provided between the inner side portion60and the outer side portion56in the top view, in a direction extending the intermediate part66. The top portion68forms a top portion that is a part that protrudes the most in the direction extending the intermediate part66. The top portion68is formed more to the outer side portion56side than a virtual center line F that extends along a center of the intermediate part66. The top portion68is formed on an outer side than the intermediate part66. The top portion68is formed into an arc-like shape in the top view. The top portion68is formed on a wall surface that faces the intermediate part66in the top view. An end portion66aof the intermediate part66, on the curved portion58side, is also formed into an arc-like shape in the top view. A curvature radius of the end portion66aof the intermediate part66, on the curved portion58side, is smaller than a curvature radius of the top portion68. Accordingly, in a flow of flush water curved in the top portion68, a flow to return from the top portion68toward the end portion66aof the intermediate part66, as indicated by an arrow F1, is separated from a surface66bon the inner side portion60side of the intermediate part66, as indicated by an arrow F2, and therefore it is possible to further suppress reduction in the force of water and disturbance in the flow that are caused by a pressure loss, and therefore, a flow of flush water curved in the top portion68may flow along the surface66bon the inner side portion side of the intermediate part66as indicated by an arrow F3.

The outer side portion56of the rim water passage46is formed to extend more forward than the intermediate part66, and the outer side portion56is also formed to extend more forward than the inner side portion60. The outer-side-portion outer side wall56aof the outer side portion56forms a linear wall surface that extends more forward than the end portion66aof the intermediate part66to form the outer side portion56. On the other hand, an inner-side-portion inner side wall60bof the inner side portion60forms a linear wall surface that extends to around the end portion66aof the intermediate part66. In this manner, the curved portion58is formed with the outer side portion56extending more forward than the intermediate part66, and thus, an angle that is formed between a flow that returns from the top portion68toward the end portion66aof the intermediate part66and the surface66bof the intermediate part66, on the inner side portion side, becomes a relatively small acute angle, and the flow is less likely to be separated from the surface66bon the inner side portion side of the intermediate part66. Furthermore, compared to a case where the outer side portion56is not formed in a manner extending more forward than the intermediate part66, because the outer side portion56is curved after extending more forward than the intermediate part66, the flow channel cross-sectional area at the curved portion58may be made relatively large. Accordingly, a change in the flow channel cross-sectional area from the outer side portion56to the curved portion58may be made small at a position where a width of the flow channel is increased from the outer side portion56toward the inner side portion60and where the flow channel cross-sectional area is increased, and also, a change in the flow channel cross-sectional area in the curved portion58, from the curved portion58toward the inner side portion60, may be suppressed. Accordingly, a change in the flow channel cross-sectional area may be suppressed along the outer side portion56, the curved portion58and the inner side portion60. For example, a change between the flow channel cross-sectional area in the outer side portion56as shown inFIG.5and the flow channel cross-sectional area in the curved portion58as shown inFIG.6is relatively small, and also, a change between the flow channel cross-sectional area in the curved portion58as shown inFIG.6and the flow channel cross-sectional area in the curved portion58as shown inFIG.7is relatively small. In this manner, a change in the flow channel cross-sectional area from the outer side portion56to the curved portion58is made relatively small.

The inner side portion60extends from the front region of the toilet main body4to the rear region of the toilet main body4behind the central transversal line E. The inner side portion60extends to around a center of the toilet main body4. An inner-side-portion outer side wall60aand the inner-side-portion inner side wall60bof the inner side portion60extend substantially in parallel to and alongside each other, and a gap between the two side walls is approximately constant. A ceiling surface and a bottom surface of the inner side portion60are formed substantially in parallel to and alongside each other, and the flow channel cross-sectional area inside the inner side portion60is maintained approximately constant in the inner side portion60. A horizontal width W1of the inner side portion60in the top view is greater than a horizontal width W2of the outer side portion56in the top view. The inner side portion60forms a flow channel that extends linearly in the front-back direction. The inner side portion60includes a spout-port-side linear portion60cthat is connected to the rim spout port portion48. The spout-port-side linear portion60cforms a flow channel that extends linearly at least up to the rim spout port portion48. The spout-port-side linear portion60cmay adjust the flow of flush water just before reaching the rim spout port portion48to be linear. For example, the inner side portion60is formed to have a length within a range of 40 mm to 60 mm. Additionally, the inner side portion60may extend and terminate in the front region more forward than the central transversal line E.

Just one rim spout port portion48is formed in an inner circumferential surface of the rim portion10, as a single rim spout portion, and the rim spout port portion48is formed to discharge water to the rear side of the bowl through the linear portion50, along a direction extending the linear portion50. The rim spout port portion48forms an opening at a rear end portion of the inner side portion60. An opening direction of the rim spout port portion48is approximately the same as a direction extending the flow channel in the spout-port-side linear portion60cof the inner side portion60. The rear right linear portion50dis positioned on a rear side of the inner-side-portion outer side wall60aof the inner side portion60, on a same straight line, and is connected to the inner-side-portion outer side wall60awhile being on the substantial same plane with the inner-side-portion outer side wall60a. Accordingly, when flush water flows out from the rim spout port portion48, the flush water may linearly flow out along the inner-side-portion outer side wall60aand the rear right linear portion50d. The rear right linear portion50dextends substantially in parallel to and alongside the inner-side-portion inner side wall60bof the inner side portion60. Accordingly, flush water that is linearly discharged may be suppressed from being disturbed. For example, the rear right linear portion50dis formed to have a length within a range of 100 mm to 120 mm.

The bowl8further includes a rim-spout-section water passageway64that extends on the rear side of the rim spout port portion48, the rim-spout-section water passageway64extending from the rim spout port portion48in the direction extending the linear portion50such as the rear right linear portion50d, for example. As shown inFIG.1, a ceiling surface64aof the rim-spout-section water passageway64is formed in a manner overhanging from an inner side of the bowl8to an outer side, and the rim-spout-section water passageway64is formed as a C-shaped cut-out passage that is formed by cutting out the bowl8in a C-shape from an opening portion on the inner side toward a wall surface on the outer side. The rim-spout-section water passageway64on a downstream side of the rim spout port portion48is formed in an overhanging manner, and thus causes flush water that is discharged to flow to the shelf surface11while suppressing splashing of the flush water. In other words, the rim-spout-section water passageway64is provided on the downstream side of the rim spout port portion48and at a same height as the shelf surface11, the rim-spout-section water passageway64being surrounded by an overhanging portion.

The rear right linear portion50dis formed to have a length shorter than a length, in the front-back direction, of the left linear portion50bthat is not provided with the rim spout port portion48(the length of the left linear portion50bin the front-back direction, between the front and rear connecting portions62), and the connecting portion62to the arc portion52is provided within the rim-spout-section water passageway64that is formed in an overhanging manner. In the top view, the connecting portion62between the rear right linear portion50dand the arc portion52and the connecting portion62between the left linear portion50band the arc portion52are approximately left-right symmetric across the center cross-section C, but the connecting portion62between the rear right linear portion50dand the arc portion52is disposed more rearward than the connecting portion62between the right linear portion50aand the arc portion52. Accordingly, because flush water that is just discharged from the rim spout portion48and that is intense hits the curvature change portion of the connecting portion62inside the overhanging rim-spout-section water passageway64, splashing of water to outside the bowl8may be suppressed. Furthermore, the arc portion formed inside the rim-spout-section water passageway64has a curvature radius that is big compared to that of the arc portion52on the rear side, and the flush water is caused to circulate from the rear right linear portion50dto the arc portion52on the rear side, via the arc portion inside the rim-spout-section water passageway64, and thus, the flush water may be circulated while reducing energy loss and water splashing.

Next, a structure and the like of the shelf surface11of the bowl8will be described in detail with reference toFIGS.8and9.FIG.8is a plan view showing the bowl and a shelf of the flush toilet according to the embodiment of the present disclosure, andFIG.9is a schematic plan view of the shelf for describing a flow of flush water on the shelf of the flush toilet according to the embodiment of the present disclosure.

First, as shown inFIG.8, in the top view, the shelf surface11of the bowl8is formed by a right linear portion40aand a left linear portion40bthat extend in parallel to each other on the right and left sides of the bowl8, a front arc portion42connected to front ends of the right and left linear portions40a,40b, and a rear arc portion44connected to rear ends of the right linear portion40aand the left linear portion40b. Specifically, the front end of the right linear portion40aand the front arc portion42are connected by a connecting portion46a, the rear end of the right linear portion40aand the rear arc portion44are connected by a connecting portion46b, the rear arc portion44and the rear end of the left linear portion40bare connected by a connecting portion46c, and the front end of the left linear portion40band the front arc portion42are connected by a connecting portion46d.

The front arc portion42and the rear arc portion44are both formed to have a single curvature radius R1. Additionally, the front arc portion42and the rear arc portion44may each be formed by combining a plurality of curvature radii.

More specifically, as shown inFIG.8, a front portion side and a rear portion side of the shelf surface11of the bowl8are each substantially left-right symmetric across a center line C1(the center cross-section C) extending in the front-back direction, and are substantially front-back symmetric across a substantially center line C2extending in a left-right width direction. Furthermore, the front arc portion42has a semicircular shape having a single radius R1with a center O1, and similarly, the rear arc portion44has a semicircular shape having a single radius R2with a center O2.

Moreover, inFIG.8, a position A is a front end of the bowl8, a position B is an intermediate position between the front end of the bowl8and the front end of the right linear portion40a, a position C is the front end of the right linear portion40a, a position D is an intermediate position of the right linear portion40a, and a position D1is a position of the rim spout port portion48, and the position D and the position D1are approximately at a same position. A position E is the rear end of the right linear portion40a, a position F is an intermediate position between the rear end of the right linear portion40aand a rear end of the bowl8, a position G is the rear end of the bowl8, a position H is an intermediate position between the rear end of the bowl8and the rear end of the left linear portion40b, a position I is the rear end of the left linear portion40b, a position J is an intermediate position of the left linear portion40b, a position K is the front end of the left linear portion40b, and a position L is an intermediate position between the front end of the left linear portion40band the front end of the bowl8. Accordingly, a line connecting the position D and the position J is the substantially center line C2, and a line connecting the position A and the position G is the center line C1. Furthermore, a length between the substantially center line C2and the position G in the front-back direction is greater than a length between the substantially center line C2and the position A in the front-back direction. Accordingly, because the bowl surface is wider on the rear side, user can feel more relaxed at the time of excretion, both when user is excreting at a standing position and at a sitting position. A length between the position C and the position E in the front-back direction and a length between the position I and the position K in the front-back direction are substantially the same, and a length between the position E and the position G in the front-back direction is greater than the length between the position C(I) and the position E(K) in the front-back direction. Furthermore, a length between the position C and the position A in the front-back direction is greater than the length between the position C(I) and the position E(K) in the front-back direction. In other words, the radii R1, R2of the front arc portion42and the rear arc portion42are greater than the length of the right (left) linear portion. In the case where the right (left) linear portion is longer than the radii R1, R2, the radii R1, R2are relatively small and the flow of flush water from the linear portions to the arc portions is drastically changed, thus possibly causing the flush water to be scattered. By contrast, when the radii R1, R2of the front arc portion42and the rear arc portion42are made greater than the length of the right (left) linear portion, a change of the flow of flush water from the linear portions to the arc portions is eased, and the flush water may be suppressed from being scattered.

Next, movement of flush water flowing on the shelf surface11of the bowl8will be described with reference toFIG.9. As shown inFIG.9, a flow of flush water flowing from the right linear portion40ato the rear arc portion44is given as F11, a flow of flush water flowing from the rear arc portion44to the left linear portion40bis given as F12, a flow of flush water flowing from the left linear portion40bto the front arc portion42is given as F13, and a flow of flush water flowing from the front arc portion42to the right linear portion40ais given as F14.

Flush water flowing along the right linear portion40aand the left linear portion40bof the shelf surface11does not easily flow down to the waste receiving surface8due to small flow channel resistance, but flush water flowing along the front arc portion42and the rear arc portion44easily flows down to the waste receiving surface8due to the flow being disturbed by the change in the direction of the flow. Influence of disturbance of the flow is greater than influence of centrifugal force.

Accordingly, with respect to the flows F12and F14of flush water flowing from the arc portions to the linear portions, the flush water does not easily flow down from the shelf surface11, and with respect to the flows F11and F13of flush water flowing from the linear portions to the arc portions, the flush water easily flows down the shelf surface11. Due to such movement of flush water, an unwashed part tends to occur on the waste receiving surface at a region X1and a region X2where the flush water flows from the arc portions to the linear portions.

In a rear region (including the region X2) of the bowl8, the rim spout port portion48is positioned at the position D1and water is discharged rearward from the rim spout port portion48, and thus, because a distance from the rim spout port portion48is relatively small, force of the flush water is strong and the flush water is greatly disturbed, and the flush water easily flows down from the rear arc portion44and unwashed portions are not easily generated. However, in a front region (including the region X1) of the bowl8, force of the flush water is weak and the flush water is not greatly disturbed, and the flush water does not easily flow down from the front arc portion42and unwashed portions are thereby easily generated. In the present embodiment, a sloping surface (an ascending surface)49that is raised toward the rim spout port portion48is formed in the region X1inFIG.9, or in other words, on the shelf surface11extending from the front arc portion42to the right linear portion40a. Because the ascending surface49is formed on the shelf surface11, a flow velocity of the flush water is reduced, and thus, unwashed portions may be suppressed from being generated on the water receiving surface8lower than the shelf surface11in the region of the rim spout port portion48(or the intermediate position D of the right linear portion40a).

Next, movement (action) of the flush water in the rim water passage46according to the embodiment of the present disclosure will be described with reference toFIGS.3and4.

Flush water that is supplied from the rim-side water supply channel2ato the rim water passage46flows inside the outer side portion56of the rim water passage46toward the front side. Because the outer side portion56extends linearly toward the front side, the flush water flows linearly with the flow adjusted along the outer side portion56. The flush water flowing from the outer side portion56and hitting the top portion68of the curved portion58positioned in front of the outer side portion56is curved relatively smoothly along the top portion68, and is returned toward the intermediate part66side. At this time, as indicated by the arrow F1, an angle α formed between the flow returning toward the end portion66aof the intermediate part66from the top portion68and the surface66bof the intermediate part66, on the inner side portion side, tends to be an acute angle, and the flow as indicated by the arrow F1may easily be caused to be along the surface66b. Accordingly, the flush water may be suppressed from being separated, as indicated by the arrow F2, on the inner side portion60side of the intermediate part66, and a flow along the surface66b, as indicated by the arrow F3, may easily be formed. Accordingly, a flow that is relatively strong and that is adjusted may easily be formed inside the inner side portion60and on the downstream side.

Additionally, if the top portion68of the curved portion58as described above is not formed at a predetermined position, a flow that is curved along the top portion68and that is returned toward the intermediate part66side is not easily formed, or a flow that separates from the surface66bof the intermediate part66, on the inner side portion60side, at the time of the flush water circulating around the end portion66aof intermediate part66is easily formed, and thus, the flow tends not to follow along the surface66b, and the flow of the flush water is easily disturbed inside the inner side portion60. In the present embodiment, the top portion68having a predetermined shape is formed at a predetermined position of the curved portion58, and thus, disturbance of the flush water may be reduced, and desirable advantageous effects may be obtained.

Next, an action of the flush toilet1according to the embodiment of the present disclosure described above will be described.

First, with the flush toilet1according to the embodiment of the present disclosure, at the bowl8where the rim portion10includes the linear portions50that are disposed alongside each other on the right and left sides of the bowl8in the top view and the arc portions52that connect the linear portions50on the right and left sides of the bowl8at the front end portions and the rear end portions of the linear portions50, one rim spout port portion48is formed in the rim portion10in such a manner as to discharge water at the linear portion50, rearward in the bowl8in the direction extending the linear portion50.

Accordingly, when forming a relatively strong circulating flow in the bowl8by one rim spout port portion48that is formed in the rim portion10, flush water that is discharged from the rim spout port portion48may be adjusted to flow, at the linear portion50, in the direction extending the linear portion50, and splashing of water at the curvature change portion connecting the linear portion50and the arc portion52on the rear side of the linear portion50may be suppressed. Accordingly, with the bowl8including the linear portions50and the arc portions52of the rim portion10, where the linear portions50extend alongside each other and the arc portions52connect the linear portions50, when water is discharged rearward in the bowl8from one rim spout port portion48that is formed in the rim portion10, splashing of water from the bowl8may be suppressed.

Furthermore, a relatively strong circulating flow may be formed in the bowl8by one rim spout port portion48formed in the rim portion10, and the waste receiving surface on the rear side in the bowl8may be flushed with flush water spreading and flowing down from the curvature change portion connecting the linear portion50and the arc portion52on the rear side of the linear portion50, and also, a circulating flow that circulates to the front side from the rear side in the bowl8may be formed. Accordingly, with the bowl8including the linear portions50and the arc portions52of the rim portion10, where the linear portions50extend alongside each other and the arc portions52connecting the linear portions50, flushing performance in the case of discharging water rearward in the bowl8from one rim spout port portion48formed in the rim portion10may be increased for the bowl8.

Next, with the flush toilet1according to the embodiment of the present disclosure, the rim water passage46that is curved in a U-turn shape may be formed inside the rim portion10by the outer side portion56, the curved portion and the inner side portion60of the rim water passage46, and a length of the rim water passage46up to the rim spout port portion48may be made relatively short and reduction in the force of flush water may be suppressed, and the flush water may be discharged from the rim spout port portion48while maintaining a relatively strong force of the flush water, and thus, flushing performance may be further increased for the bowl8.

Furthermore, with the flush toilet1according to the embodiment of the present disclosure, because the outer side portion56of the rim water passage46includes the curved-portion-side linear portion56cthat is connected to the curved portion58, the pressure loss of the flush water at the outer side portion56may be reduced compared to a case where the outer side portion56includes a curved portion connected to the curved portion58, and thus, flush water with a relatively strong force may be supplied to the rim spout port portion48. Furthermore, flush water passing through the rim water passage46flows to the curved portion58in a state where the flow is adjusted to be linear by the curved-portion-side linear portion56c, and thus, compared to a case where the flush water flows to the curved portion58in a disturbed state, the pressure loss of the flush water at the curved portion58may be reduced, and thus, flow of flush water with a relatively strong force may be supplied to the rim spout port portion48.

Furthermore, with the flush toilet1according to the embodiment of the present disclosure, because the inner side portion60of the rim water passage46includes the spout-port-side linear portion60cthat is connected to the rim spout port portion48, the pressure loss of the flush water at the inner side portion60may be reduced compared to a case where the inner side portion60includes a curved portion connected to the rim spout port portion48, and thus, flush water with a relatively strong force may be supplied to the rim spout port portion48. Furthermore, flush water passing through the rim water passage46is discharged from the rim spout port portion48in a state where the flow is adjusted to be linear by the spout-port-side linear portion60c, and thus, compared to a case where the flush water is discharged from the rim spout port portion48in a disturbed state, the flush water may be discharged in a state where the flow is better adjusted, and splashing of water at the curvature change portion may be better suppressed. Furthermore, because the flush water is discharged from the rim spout port portion48in a state where the flow is adjusted to be more linear, the pressure loss may be reduced for the flush water that is discharged from the rim spout port portion48, and a stronger circulating flow may be formed inside the bowl8.

Furthermore, with the flush toilet1according to the embodiment of the present disclosure, the curved portion58is provided at a position more rearward than the connecting portion62between the linear portion50and the arc portion52on the front side of the linear portion50. Accordingly, in contrast to a case where the curved portion58is formed at a position more forward than the connecting portion62between the linear portion50and the arc portion52on the front side of the linear portion50, the curved portion58may be curved inside the rim portion10on the linear portion50side without being curved inside the rim portion10on the arc portion52side, and the pressure loss at the curved portion58may be reduced. Moreover, an external appearance may be suppressed from being impaired due to a width of the rim portion10becoming relatively great on the arc portion52side because of the curved portion58being curved inside the rim portion10on the arc portion52side, and also, a reduction in a size of the waste receiving surface of the bowl8and the like may be suppressed, for example.

Furthermore, with the flush toilet1according to the embodiment of the present disclosure, the bowl8further includes the rim-spout-section water passageway64that extends on the rear side of the rim spout port portion48, the rim-spout-section water passageway64extending from the rim spout port portion48in the direction extending the linear portion50, and the ceiling surface of the rim-spout-section water passageway64is formed in a manner overhanging from the inner side of the bowl8to the outer side, and the rim-spout-section water passageway64is formed in a manner cutting out the bowl8from the inner side to the outer side. Accordingly, upward splashing of flush water discharged from the rim spout port portion48may be suppressed by the ceiling surface, and also, the flow may be adjusted at the rim-spout-section water passageway64to be along the direction extending the linear portion50, and splashing of water at the curvature change portion that connects the linear portion50and the arc portion52on the rear side of the linear portion50may be better suppressed. Accordingly, with the bowl8including the linear portions50and the arc portions52of the rim portion10, where the linear portions50extend alongside each other and the arc portions52connect the linear portions50, a splashing from the bowl8may be better suppressed at a time when water is discharged rearward inside the bowl8from one rim spout port portion48formed in the rim portion10.