JP7480624B2 - Flush water tank device and flush toilet equipped with same - Google Patents

Description

The present invention relates to a flush water tank device and a flush toilet equipped with the same, and in particular to a flush water tank device that supplies flush water to the toilet body by jet pump action, and a flush toilet equipped with the same.

Conventionally, as described in Patent Documents 1-4, for example, flush water tank devices equipped with a water storage tank main body that can store flush water to flush the toilet body have been known, in which the forceful flow of flush water sprayed from a jet nozzle toward the suction port of the throat pipe creates a negative pressure that directly draws in surrounding flush water, such as near the suction port of the throat pipe, without relying on other mechanical elements such as a pump, and this negative pressure is used to pressure-feed the flush water in the water storage tank main body that has been sucked into the throat pipe toward the toilet body, supplying flush water to the toilet body by a so-called "jet pump action."
These conventional flush water tank devices are equipped with a jet pump unit that induces the above-mentioned jet pump action. This jet pump unit specifically comprises a throat pipe that forms a drainage channel in the water storage tank body, a jet nozzle, etc. The upstream end of the throat pipe is formed with a suction port through which flush water is sprayed from the jet nozzle and sucked in, and the downstream end of the throat pipe is connected to the inlet of the water conduit in the toilet body. When flush water is sprayed from the jet nozzle toward the suction port of the throat pipe by this jet pump action, the above-mentioned jet pump action is induced in the water storage tank body, and flush water is supplied from the water storage tank body side to the water conduit on the toilet body side.
Furthermore, in conventional flush water tank devices, a small tank for switching between large and small flushes is further provided to divide (compartment) the water storage tank body so that the amount of flush water supplied to the toilet body can be switched between large and small.
Furthermore, the small tank is provided with a switching opening formed to penetrate the partition wall that separates the internal and external areas, and a large/small flush switching valve is provided in this switching opening so that it can be opened and closed. As a result, during a large flush of the flush toilet, the large/small flush switching valve is in an open state, and the internal area of the small tank separated by the partition wall communicates with the external area, allowing a large flush volume of flush water to be supplied from the storage tank body to the toilet body.
On the other hand, during a small flush of the flush toilet, the large/small flush switching valve is closed, and the flush water in the internal area of the small tank remains in the small tank without contributing to the small flush of the toilet, and only the flush water in the external area of the small tank is supplied to the toilet body and contributes to the small flush of the toilet.

JP 2015-206158 A JP 2015-206159 A JP 2015-151758 A JP 2002-327479 A

Additionally, in recent years, in order to reduce the overall projection dimension of a flush toilet (more specifically, the front-to-rear distance from the rear wall of the toilet space in which the flush toilet is installed to the front-most edge of the flush toilet), there has been a demand for ways to miniaturize the flush water tank device while still ensuring the flushing performance of the toilet.
However, the internal space of the storage tank body of the above-mentioned conventional flush water tank device, which supplies flush water from the storage tank body to the toilet body by jet pump action, is occupied by a water supply valve device that supplies flush water supplied from a water source into the storage tank body, and related parts of the jet pump unit.
For this reason, the smaller the water tank body itself is made, the more likely it is that the supply performance of the flushing water supplied from the water tank body to the toilet body will be reduced, making it difficult to secure a sufficient amount of flushing water to perform toilet flushing, which poses the problem of a risk of reducing toilet flushing performance.
Furthermore, in conventional flush water tank devices that use a small tank for switching between large and small flushes, allowing the amount of flush water supplied to the toilet body to be switched between large and small, the smaller the water storage tank body itself is made, the more it is necessary to make the small tank within the water storage tank body small while still maintaining the required water storage capacity.
Furthermore, in the conventional flush water tank device described above, the smaller the water tank body itself is made, the greater the impact of residual water in the water tank body on reducing flushing performance, so a required issue is how to position a small tank so as not to obstruct the flow of flush water within the water tank body, and improve the flow straightening of the flush water within the water tank body.
However, in the conventional flush water tank device described above, the small tank is roughly rectangular and open at the top, so it occupies a relatively large proportion of the internal space of the water storage tank body, making it difficult to reduce the size of the water storage tank body and also difficult to improve the flow straightening of the flush water within the water storage tank body.
Therefore, a required issue is how to achieve both miniaturization of the small tank and the entire water storage tank body and the supply performance of flush water supplied from the water storage tank body to the toilet body and toilet flushing performance.

The present invention has been made to solve the problems of the prior art and issues that have been required in recent years, and aims to provide a flush water tank device that improves the flow of flush water throughout the water storage tank body, and can achieve both miniaturization of the small tank and the entire water storage tank body, as well as the supply performance of flush water supplied from the water storage tank body to the toilet body and toilet flushing performance, and a flush toilet equipped with the same.

In order to solve the above-mentioned problems, the present invention provides a flush water tank device that supplies flush water to the toilet body of a flush toilet by jet pump action, comprising: a water storage tank body that is capable of storing flush water for flushing the toilet body; a water supply valve device that includes a water supply valve that is capable of stopping the supply of flush water supplied from a water supply source into the water storage tank body; an operating section that enables the opening operation of the water supply valve of the water supply valve device and enables the switching operation of setting the amount of flush water supplied to the toilet body to either large or small when starting a toilet flush; and a jet pump unit that is disposed with at least a portion thereof submerged in the water storage tank body, the jet pump unit comprising: a throat pipe that forms a drainage channel of the water storage tank body, the upstream end of which forms a suction port and the downstream end of which forms a discharge port connected to an inlet of a water conduit of the toilet body; and a jet nozzle that sprays flush water toward the suction port of the throat pipe to induce a jet pump action; and a small tank for switching between large and small flushes that forms a small space in which less flush water is stored than the flush water supplied to the toilet body, the small tank for switching between large and small flushes comprising a partition wall that extends vertically within the water storage tank body to separate an internal area from an external area of the small tank, and a switching opening formed to penetrate the partition wall; and a large/small flush switching valve that is provided to be opened and closed with respect to the switching opening of the small tank by operation of the operating unit, and that enables the amount of flush water supplied to the toilet body through the jet pump unit to be switched between large and small, the small tank comprising a small tank main body portion that is provided to extend from one of the left and right sides within the water storage tank body to the other side in the longitudinal direction, and a protrusion that protrudes downward from the lower end of the other side of the small tank main body portion to the bottom surface of the water storage tank body, the overall shape of the small tank that extends from one of the left and right sides of the small tank main body portion to the other side in the longitudinal direction and then protrudes downward by the protrusion is generally L-shaped when viewed from the front, and the switching opening is provided in the protrusion.
In the present invention configured in this manner, for example, when the operating part is operated to start a large flush of the toilet body of the flush toilet, the water supply valve of the water supply valve device opens, the large/small flush switching valve is opened, and the switching opening of the small tank for switching between large and small flushes is opened.
As a result, wash water supplied from the water supply source passes through the water supply valve of the water supply valve device and is supplied to the jet nozzle of the jet pump unit. Then, wash water is sprayed from the jet nozzle toward the suction port of the throat pipe, inducing a jet pump action in the water storage tank body.
Furthermore, due to this jet pump action, the forceful flow of flush water sprayed from the jet nozzle toward the suction port of the throat pipe creates a negative pressure that directly draws in surrounding flush water, such as near the suction port of the throat pipe, without relying on other mechanical elements such as a pump. This negative pressure then pressures the flush water in the water storage tank body that has been sucked into the throat pipe and is pumped toward the toilet body. As a result, a large volume of flush water is supplied from the water storage tank body to the toilet body, and a large flush is performed in the toilet body.
In this case, the overall shape of the small tank, which extends from one of the left and right sides of the small tank main body to the other side in the longitudinal direction and then protrudes downward by the protruding portion, is generally L-shaped when viewed from the front. Therefore, the entire small tank can be made smaller while making effective use of the longitudinal space within the water tank main body, compared to a small tank that is generally rectangular in shape when viewed from the front.
In addition, since the protrusion of the small tank itself protrudes downward from the lower end of the small tank main body and is positioned on the bottom side of the water storage tank main body, the switching opening provided in the protrusion can also be brought close to the bottom surface of the water storage tank main body.
This allows flush water discharged from the switching opening of the small tank into the water storage tank body in the area outside the small tank to flow smoothly within the bottom side area within the water storage tank body.
Furthermore, since the entire small tank formed in the small tank main body and the protrusion is formed in a roughly L-shape when viewed from the front, the area other than the protrusion between the small tank main body and the bottom surface of the water storage tank body can also be effectively utilized as storage space for storing cleaning water.
Furthermore, the area (storage space) other than the protrusion between the bottom surface of the small tank main body and the bottom surface inside the water storage tank main body can also be used as a straightening area for straightening the cleaning water discharged from the switching opening of the small tank, thereby making it possible to reduce the size of the small tank and the entire water storage tank main body while improving the straightening of the cleaning water throughout the water storage tank main body.
As a result, the flow straightening of the flushing water throughout the entire water storage tank body can be improved, making it possible to achieve both miniaturization of the small tank and the entire water storage tank body, as well as improved supply performance of the flushing water supplied from the water storage tank body to the toilet body and improved toilet flushing performance.

In the present invention, preferably, the water tank body has a longitudinal center axis that divides its internal region into a front region and a rear region, respectively, from the front to the rear, and a transverse center axis that divides the internal region into a left and right one side region and a right and left other side region, and the protrusion is arranged within the water tank body in a region on the other side of the transverse center axis where the suction port is not located, relative to a region on the left or right side of the transverse center axis where the suction port is located, and is arranged in a region on the other side of the longitudinal center axis where the center of the discharge port is not located, relative to a region on the front or rear side of the longitudinal center axis where the center of the discharge port of the throat pipe is located.
In the present invention configured in this manner, the cleaning water stored in the area on the discharge side of the throat pipe of the jet pump unit within the water storage tank body flows toward the suction port side, avoiding the discharge port of the throat pipe, due to the suction force from the suction port side of the throat pipe caused by the jet pump action.
In this case, if the protruding portion of the small tank is located in an area to the left or right of the short-side central axis of the water storage tank body where the suction port of the throat pipe is located, or if the protruding portion of the small tank is located in an area to the front or rear of the long-side central axis of the water storage tank body where the center of the discharge port of the throat pipe is located, the distance from the switching opening of the small tank to the suction port will be too short. This makes it difficult to secure a straightening area in the water storage tank body that straightens the flush water discharged from the switching opening of the small tank, and the straightening of the flush water in the entire water storage tank body will decrease.
Furthermore, if the flow straightness of the flushing water throughout the water storage tank body decreases, the flushing water discharged from the switching opening of the small tank will not be supplied smoothly to the suction port side of the throat pipe, which may result in residual water remaining in the small tank or a decrease in the supply performance of the flushing water supplied from the water storage tank body to the toilet body and the toilet flushing performance.
In contrast, in the present invention, the protrusion of the small tank is positioned within the water tank body in an area on one side of the short center axis of the water tank body where the suction port is located, but on the other side of the short center axis where the suction port is not located, and is positioned in an area on the other side of the long center axis of the water tank body where the center of the throat pipe outlet is not located, but on the other side of the long center axis of the water tank body where the center of the throat pipe outlet is located, so that the area other than the protrusion between the bottom surface of the small tank main body and the bottom surface of the water tank body can also be effectively utilized as storage space for storing cleaning water.
In addition, such storage space can also be used as a straightening area to straighten the flushing water discharged from the switching opening of the small tank, thereby improving the straightening of the flushing water throughout the entire water storage tank body while achieving a smaller size for the small tank and the entire water storage tank body.
As a result, the flow of flushing water within the entire water storage tank body is improved, making it possible to achieve a balance between miniaturization of the small tank and the entire water storage tank body and the supply performance of flushing water supplied from the water storage tank body to the toilet body and toilet flushing performance.

In the present invention, the protruding portion is preferably formed so as to protrude from the lower end of the small tank body portion to a bottom surface within the water storage tank body located below this lower end.
In the present invention configured in this manner, the protrusion of the small tank is formed to protrude from the lower end of the small tank main body to the bottom surface of the water storage tank main body, which is located below this lower end, thereby ensuring the largest possible volume within the small tank.
In addition, by making the protruding portion of the small tank protrude to the bottom surface of the water storage tank body, the space between the bottom surface of the entire small tank and the bottom surface of the water storage tank body can be reduced, which can reduce the residual water space in the distal region of the water storage tank body that is separated from the suction port of the throat pipe.
Therefore, the suction force from the suction port side of the throat pipe is easily spread to all of the flush water in the water storage tank body by the jet pump action, and all of the flush water in the water storage tank body is easily supplied to the suction port. This improves the supply performance of flush water supplied from the water storage tank body to the toilet body, and therefore improves toilet flushing performance.

In the present invention, preferably, the water tank body comprises a bottom surface on which the lowest bottom surface of the protruding portion of the small tank is located, and a jet nozzle accommodating portion formed to protrude downwardly in an area on one of the left and right sides of the bottom surface and capable of accommodating the jet nozzle, and the protruding portion of the small tank is formed to protrude downwardly from the lower end of the small tank main body portion to the bottom surface within the water tank body.
In the present invention configured in this manner, the protrusion of the small tank is formed to protrude downward from the lower end of the small tank main body to the bottom surface of the water storage tank main body, and a jet nozzle accommodating portion capable of accommodating a jet nozzle is formed to protrude downward in the area on one of the left and right sides of the bottom surface of the water storage tank main body.Therefore, the cleaning water discharged from the switching opening of the small tank into the water storage tank main body in the external area of the small tank is straightened while flowing within the space between the bottom surface of the small tank main body and the bottom surface of the water storage tank main body, and then flows toward the jet nozzle of the jet nozzle accommodating portion and the suction port of the throat tube.
Therefore, the flow straightening of the flushing water throughout the water storage tank body can be improved, and all of the flushing water within the water storage tank body can be easily supplied to the suction port, thereby improving the supply performance of the flushing water supplied from the water storage tank body to the toilet body and the toilet flushing performance.

In the present invention, preferably, the jet pump unit further includes a flow path switching valve provided in the jet nozzle accommodating portion for switching the flow path of the cleaning water sprayed from the jet nozzle, and this flow path switching valve is capable of switching the flow path of the cleaning water sprayed from the jet nozzle to either a drainage path that flows into the suction port of the throat pipe, or a water supply path that supplies water to the inside of the water storage tank body other than the suction port, depending on the water level in the water storage tank body.
In the present invention configured in this manner, the flow path switching valve of the jet pump unit, which enables switching of the flow path of the cleaning water sprayed from the jet nozzle, is provided within the jet nozzle accommodating section in the water storage tank main body, so that some of the related elements of the jet pump unit (jet nozzle, flow path switching valve) can be concentrated within the jet nozzle accommodating section.
Therefore, the entire water storage tank body can be made smaller, and the supply performance of flush water supplied from the water storage tank body to the toilet body can be further improved in the limited space within the water storage tank body.

In the present invention, it is preferable that the toilet further comprises an overflow pipe which, when the water level in the water storage tank body rises above the stop water level at which water is stopped by the water supply valve device, causes flushing water which has risen above this stop water level to overflow into the water conduit side of the toilet body, and a make-up water conduit which enables a portion of the flushing water sprayed from the jet nozzle to be supplied into the overflow pipe as make-up water, the upstream side of the make-up water conduit being connected into the jet nozzle accommodating section, and when the flow path switching valve is switched to a water supply conduit which supplies water to the water storage tank body other than the suction port, it enables a portion of the flushing water sprayed from the jet nozzle to be made to make-up water conduit.
In the present invention configured in this manner, the upstream side of the make-up water passage, which enables a portion of the cleaning water sprayed from the jet nozzle to be supplied into the overflow pipe as make-up water, is connected to the jet nozzle accommodating section, so that when the flow path switching valve is switched to the water supply passage that supplies water to the water storage tank body other than the suction port, a portion of the cleaning water sprayed from the jet nozzle can be made into make-up water passage as make-up water.
Therefore, some of the related elements of the jet pump unit (jet nozzle, flow path switching valve, upstream side of the supply water passage) can be concentrated within the jet nozzle accommodating section, thereby making it possible to reduce the size of the entire water storage tank body and further improving the supply performance of the flushing water supplied from the water storage tank body to the toilet body in the limited space within the water storage tank body.

In the present invention, the switching opening is preferably provided on one side in the left-right longitudinal direction of the protruding portion.
In the present invention configured in this manner, the switching opening of the small tank is provided on one side of the left and right longitudinal direction of the protrusion, so that the cleaning water in the small tank can be pre-rectified within the left and right longitudinal area of the protrusion before being discharged from the switching opening.
This means that even if the opening cross-sectional area of the switching opening of the small tank is not set large, the cleaning water in the small tank can be pre-rectified without being retained in the protruding portion, and then smoothly and stably discharged from the switching opening toward the suction port side of the throat pipe in the water storage tank main body.
Therefore, the amount of residual water in the small tank can be reduced, and the flow of flush water discharged from the switching opening of the small tank and directed toward the vicinity of the suction port of the throat pipe can be straightened.
Therefore, the flushing water discharged from the switching opening of the small tank can be pre-rectified and stabilized so that it merges with the main flushing water in the storage tank body, which has been stored in advance in the external area of the small tank, and the main flow of the flushing water heading toward the suction port of the throat pipe. This improves the straightening of the flushing water throughout the storage tank body, and improves the supply performance of the flushing water supplied from the storage tank body to the toilet body.

In the present invention, the maximum width dimension of the protrusion in the front-to-rear short direction is preferably set to be smaller than the maximum width dimensions of each of the two equal parts when the internal area of the water tank body is divided in the short direction.
In the present invention configured in this way, the maximum width dimension in the front-to-rear short-side direction of the protruding portion of the small tank is set to be smaller than the maximum width dimension of each of the two equal parts when the internal area of the water storage tank body is divided in the short-side direction, so that the water storage area in the front-to-rear direction in the external area of the small tank within the water storage tank body can be secured while making the entire water storage tank body smaller. Therefore, a relatively large distance can be secured until the flush water in the front-to-rear water storage area in the external area of the small tank is sucked into the suction port of the throat pipe, improving flow straightening.
Therefore, in the limited space within the water storage tank body, it is possible to improve the flow regulation of flush water throughout the water storage tank body, and improve the supply performance of flush water supplied from the water storage tank body to the toilet body.

In the present invention, the protrusion is preferably arranged within the water tank body in a region on one side of the short side center axis of the water tank body where the suction port is provided, and in a region on the other side of the short side center axis where the suction port is not provided, and is arranged in a region forward of the longitudinal center axis, so as to be spaced apart from the suction port.
In the present invention configured in this manner, the protrusion of the small tank can be positioned within the water tank body in an area to the left or right of the short center axis of the water tank body where the suction port of the throat pipe is located, and in an area to the left or right of the short center axis of the water tank body where the suction port is not located, as well as in an area forward of the longitudinal center axis of the water tank body, so that it is spaced apart from the suction port.
This makes it possible to reduce the external area (water storage area) of the small tank within the water storage tank body, which is located at a great distance from the suction port, by the protruding portion of the small tank.
In addition, the volume of the area behind the longitudinal center axis within the water tank body, which is at a distance from the suction port, is also reduced by the same amount that the external area of the small tank within the water tank body is reduced by the protruding portion of the small tank in the area forward of the longitudinal center axis within the water tank body.
Therefore, the distance that flush water stored in an area of the water storage tank body that is far from the suction port flows when it is sucked into the suction port side can also be shortened by the amount reduced by the protruding part of the small tank. This reduces the pressure loss when all of the flush water in the water storage tank body is sucked into the suction port side, allowing it to flow smoothly to the suction port.
Therefore, all of the flush water in the water storage tank body is more easily supplied to the suction port, improving the supply performance of flush water supplied from the water storage tank body to the toilet body.

Next, the present invention is a flush toilet equipped with the above-mentioned flush water tank device.
With the present invention configured in this manner, it is possible to provide a flush toilet equipped with a flush water tank device that improves the flow of flush water throughout the entire water storage tank body, thereby achieving both the miniaturization of the small tank and the entire water storage tank body, and the supply performance of flush water supplied from the water storage tank body to the toilet body and toilet flushing performance.

The flush water tank device of the present invention, and the flush toilet equipped with it, improves the flow of flush water throughout the entire water storage tank body, making it possible to achieve both miniaturization of the small tank and the entire water storage tank body, and improved supply performance of flush water supplied from the water storage tank body to the toilet body and toilet flushing performance.

1 is a plan view showing a flush toilet equipped with a flush water tank apparatus according to an embodiment of the present invention. FIG. 2 is a side view of a flush water tank apparatus according to one embodiment of the present invention, and is a cross-sectional view taken along line II-II of the flush toilet shown in FIG. 1. 1 is a block diagram showing the basic configuration of a flush water tank apparatus according to an embodiment of the present invention. 1 is a schematic front cross-sectional view of a water storage tank body and a small tank, illustrating the basic configuration of a flush water tank apparatus according to an embodiment of the present invention. 2 is a plan view showing the internal structure of the water storage tank body of a flush water tank apparatus according to an embodiment of the present invention; FIG. This is a partially enlarged front cross-sectional view of the jet nozzle accommodating portion in the water storage tank body of a flush water tank device according to one embodiment of the present invention, showing the state in which the flow path switching valve is set in the flow path on the suction port side of the throat pipe. This is a partially enlarged front cross-sectional view of the jet nozzle accommodating portion in the water storage tank body of a cleaning water tank device according to one embodiment of the present invention, showing the state in which the flow path switching valve is set in the flow path on the water storage tank body side other than the suction port side of the throat pipe. 2 is a partial front cross-sectional view showing an enlarged view of the water storage tank body and small tank of a flush water tank apparatus according to one embodiment of the present invention; FIG. 1 is a perspective view of a small tank of a flush water tank apparatus according to an embodiment of the present invention, viewed diagonally from above and to the front right. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 9 is a partially enlarged perspective view showing an enlarged portion of the large/small flush switching valve device of the flush water tank apparatus according to one embodiment of the present invention shown in FIG. 8 . FIG. 1 is a partially enlarged view of the large/small flush switching valve device in a flush water tank apparatus according to one embodiment of the present invention, showing the open state of the switching valve body of the large/small flush switching valve device in a standby state before the start of the toilet flush operation and when the large flush operation of the toilet has begun. FIG. 2 is a partially enlarged view of the large/small flush switching valve device in a flush water tank apparatus according to one embodiment of the present invention, showing the closed state of the switching valve body of the large/small flush switching valve device when the small flush operation of the toilet has begun. 1 is a partially enlarged view of the large/small flush switching valve device in a flush water tank apparatus according to an embodiment of the present invention, showing the closed state of the switching valve body of the large/small flush switching valve device during a small flush of the toilet. FIG. This is a partially enlarged view of the large/small flush switching valve device in a flush water tank device according to one embodiment of the present invention, showing the state in which the switching valve body of the large/small flush switching valve device, which is in a closed state, opens while water is being supplied from the water supply valve device to the water storage tank body after the small flush of the toilet has been completed. 4 is a flowchart showing the flow of operation of a flush water tank apparatus according to one embodiment of the present invention.

A flush toilet equipped with a flush water tank apparatus according to one embodiment of the present invention will now be described with reference to the accompanying drawings.
First, the basic structure of a flush toilet equipped with a flush water tank apparatus according to one embodiment of the present invention will be described with reference to Figs. 1 and 2.
FIG. 1 is a plan view showing a flush toilet equipped with a flush water tank apparatus according to one embodiment of the present invention, and FIG. 2 is a side view of the flush water tank apparatus according to one embodiment of the present invention, and is a cross-sectional view taken along line II-II of the flush toilet shown in FIG.

1 and 2, a flush toilet 2 equipped with a flush water tank apparatus 1 according to one embodiment of the present invention comprises a toilet body 4. The flush water tank apparatus 1 of this embodiment, the details of which will be described later, is disposed on the upper surface of the rear side of this toilet body 4.
Next, as shown in Figures 1 and 2, the toilet body 4 comprises a bowl portion 6 provided on its front side, a rim portion 8 formed on the upper edge of the bowl portion 6, and a shelf portion 10 formed on the inner circumference of the rim portion 8.
Furthermore, an inlet 12a of a trap drainage channel 12 opens at the bottom of the bowl portion 6 of the toilet body 4, and this trap drainage channel 12 is equipped with an uprising pipe 12b extending upward and a downcomer pipe 12c extending downward. As can be seen from the shape of this trap drainage channel 12, the flush toilet 2 according to this embodiment is a wash-down type toilet that discharges waste by a drop in height.
In this embodiment, a form applied to a wash-down toilet will be described, however, the present invention is not limited to this form and can also be applied to other types of flush toilets, such as a so-called siphon type toilet, which uses the siphon action to suck up waste in the bowl and discharge it to the outside all at once through the drain trap pipe.

Next, the toilet body 4 is equipped with a water conduit 16 into which flushing water discharged from the drain outlet 14 of the flushing water tank device 1 flows, a first rim spout 18 formed in the center of the left side when viewed from the front of the shelf portion 10, and a second rim spout 20 formed in the rear right side when viewed from the front.
In addition, the water conduit 16 branches downstream into a first water conduit 16a and a second water conduit 16b, and the flushing water in the water conduit 16 reaches the first rim outlet 18 via the first water conduit 16a, while reaching the second rim outlet 20 via the second water conduit 16b. The flushing water is discharged from the first rim outlet 18 and the second rim outlet 20, respectively, to wash the bowl portion 6 and discharge waste matter from the trap drain 12.

Next, the flush water tank assembly 1 of this embodiment will be described in detail with reference to Figures 1 to 11D.
First, Fig. 3 is a block diagram showing the basic configuration of a flush water tank apparatus according to one embodiment of the present invention. Also, Fig. 4 is a schematic front cross-sectional view of the storage tank main body and small tank showing the basic configuration of a flush water tank apparatus according to one embodiment of the present invention. Furthermore, Fig. 5 is a plan view showing the internal structure of the storage tank main body of a flush water tank apparatus according to one embodiment of the present invention.
In addition, in the flush water tank device 1 shown in Figure 3, for convenience, the entire internal structure of the water storage tank main body 22 has been diagrammatically simplified, and therefore the structural arrangement of the flush water tank device 1 shown in Figures 4 and 5 is different.
Also, in the flush water tank apparatus 1 shown in FIG. 4, some of the structure has been simplified.
Furthermore, with regard to the left-right direction of the flush water tank device 1 shown in Figures 1 to 11D, the left side in the left-right direction when viewed from the front side (user side) of the toilet body 4 of the flush toilet 2 is defined as the "left side," and the right side in the left-right direction when viewed from the front side of the toilet body 4 is defined as the "right side."

First, as shown in Figures 3 to 5, the flush water tank device 1 comprises a ceramic outer tank T, a water storage tank body 22 which is an inner tank housed within this outer tank T, and a water supply pipe 24 connected to a water source such as a water line (not shown).
In the water storage tank body 22 , a portion of the flush water supplied via a water supply pipe 24 is stored so that it can be supplied to the water passage 16 of the toilet body 4 .
As shown in FIG. 4, the water tank body 22 is disposed at a relatively low position on the rear side of the toilet body 4, and the upper end of the water tank body 22 is positioned at a low height, making it a so-called low silhouette type tank, and as shown in FIG. 5, it is formed in a flat shape that is long in the left-right direction when viewed from above.

Next, as shown in FIGS. 3 to 5, a water supply valve device 28 is provided inside the water storage tank body 22 for stopping the supply of flush water supplied from the water supply pipe 24 via the constant flow valve 26.
The water supply valve device 28 includes a main valve 30 which is a water supply valve that opens and closes the water supply passage downstream of the constant flow valve 26 .
The flush water tank apparatus 1 also includes an operating device 32 (operating lever 32a, drive rotation shaft 32b) which is an operating section for operating the water supply valve apparatus 28 when starting a toilet flush.

Next, the internal structure and operating mechanism of the water supply valve device 28 will be described in detail with reference to FIGS.
First, the water supply valve device 28 further includes a poppet valve 34 , a float 36 , and a float-side pilot valve 38 .
The poppet valve 34 is an operating side pilot valve that opens and closes the main valve 30 by rotating the operating lever 32a and the drive shaft 32b of the operating device 32. The float 36 moves up and down by buoyancy according to the water level in the water storage tank body 22. The float side pilot valve 38 opens and closes the main valve 30 by the up and down movement of the float 36.

Next, the main structure of the main valve 30 portion of the water supply valve device 28 includes a main valve body 30a, which is a pilot-type diaphragm valve, a main valve seat 30b on which the main valve body 30a sits, and a pressure chamber 30c which causes the main valve body 30a to move relative to the main valve seat 30b due to internal pressure.
As a result, the water supply valve device 28 can be switched between either a water-stopping state in which the main valve body 30a is seated on the main valve seat 30b to stop the water from flowing, or a water-supplying state in which the main valve body 30a is separated from the main valve seat 30b to supply water.
The pressure chamber 30c is provided with a poppet hole 34a and a float-side pilot hole 38a for releasing the pressure in the pressure chamber 30c.
Furthermore, a poppet valve 34 is provided in a poppet hole 34a of the pressure chamber 30c so as to be able to open and close. This poppet valve 34 is connected to a drive rotation shaft 32b that connects the operating lever 32a and the water supply valve device 28. This drive rotation shaft 32b is rotatable about its axis in conjunction with manual operation of the operating lever 32a by the user, and forms part of an operating section for operating the water supply valve device 28.
Furthermore, a float side pilot hole 38a of the pressure chamber 30c is provided with a float side pilot valve 38. This float side pilot valve 38 can be opened and closed by the float 36 moving up and down according to the water level of the flush water in the water storage tank body 22.
It is also possible to provide an electromagnetic valve instead of the poppet valve 34 and to change the operating device 32 to a switch or the like.

In addition, a bleed hole (not shown) is provided in the main valve body 30a, and when the water flow is stopped, the bleed hole (not shown) connects the primary side flow path A of the water supply pipe 24 to the inside of the pressure chamber 30c.
The poppet hole 34a is formed so that its opening area is larger than the opening area of the float-side pilot hole 38a. Also, the poppet hole 34a is formed at a higher position than the float-side pilot hole 38a, as shown in FIG.

Furthermore, as shown in FIG. 4, the water supply valve device 28 is normally in a water stop state, in which the poppet hole 34a and the float side pilot hole 38a are both closed, and the primary side flow path A of the water supply pipe 24 is connected to the pressure chamber 30c through a bleed hole (not shown).
As a result, the water pressure in the primary side flow path A of the water supply pipe 24 and the pressure chamber 30c is the same water pressure (primary side flow path pressure α), and the secondary side flow path B of the water supply pipe 24 is open to the atmosphere.Since the area on which the water pressure acts on the main valve body 30a is larger than the area of the primary side flow path A, the main valve body 30a is pressed against the main valve seat 30b and is in a closed state.

Next, in the water supply valve device 28, when the poppet hole 34a is opened by the poppet valve 34 and/or the float side pilot hole 38a is opened by the float side pilot valve 38, cleaning water flows out of the pressure chamber 30c and the pressure in the pressure chamber 30c decreases.
As a result, the main valve body 30a moves away from the main valve seat 30b to open the valve and enter a water discharge state.

In addition, in the water supply valve device 28, when the poppet hole 34a is closed by the poppet valve 34 and the float side pilot hole 38a is closed by the float side pilot valve 38, the pressure in the pressure chamber 30c again becomes the primary side flow path pressure α, the main valve body 30a moves toward the main valve seat 30b, and finally the valve is closed (water stop state).
At this time, the cleaning water in the primary side flow path A is injected little by little into the pressure chamber 30c through the bleed hole, so that the main valve body 30a is closed (water-stopped state) a predetermined time later after the poppet hole 34a and the float side pilot hole 38a are closed.
A jet pump unit 42 (details of which will be described later) is provided in the water supply passage downstream of the water supply valve device 28 and connected via a vacuum breaker valve 40 .

Next, the jet pump unit 42 will be described in detail with reference to FIGS. 3 to 6B.
First, as shown in Figures 3 to 5, the jet pump unit 42 is provided downstream of a water supply pipe 44 extending from the vacuum breaker valve 40, and includes, from the upstream side to the downstream side, a jet nozzle 46, a flow path switching valve 48, and a throat pipe 50.
In addition, each of these jet nozzles 46, flow path switching valve 48, and suction port 50a of the throat pipe 50 are arranged within a jet nozzle accommodating section H that protrudes downward from one of the left and right sides of the water storage tank body 22 (the right side when looking at the water storage tank body 22 from the front side in Figure 3).

6A and 6B show partially enlarged front cross-sectional views of the jet nozzle housing portion in the water storage tank body of a flush water tank apparatus according to one embodiment of the present invention.
FIG. 6A shows a state in which the flow passage switching valve 48 of the jet pump unit 42 is set in the flow passage on the suction port 50 a side of the throat pipe 50 .
On the other hand, FIG. 6B shows a state in which the flow path switching valve 48 of the jet pump unit 42 is set to the flow path on the water storage tank body 22 side other than the suction port 50 a side of the throat pipe 50 .
As shown in Figures 4 to 6B, the jet nozzle 46 of the jet pump unit 42 is positioned at least partially submerged inside the water storage tank body 22, and sprays cleaning water supplied from a water supply pipe 44 extending from the vacuum breaker valve 40.
The vacuum breaker valve 40 is provided to suck in air from the outside and prevent the inside of the water supply pipe 44 from the vacuum breaker valve 40 to the jet nozzle 46 from becoming negative pressure.

Next, as shown in Figures 3 to 6B, the flow path switching valve 48 of the jet pump unit 42 is provided near the downstream side of the jet nozzle 46, and is capable of switching the flow path of the cleaning water sprayed from the jet nozzle 46 depending on the water level in the water storage tank main body 22.
3 to 6B, the throat pipe 50 of the jet pump unit 42 is provided in the vicinity of the downstream side of the flow path switching valve 48. A suction port 50a is formed at one end (upstream end) of the throat pipe 50, while a discharge port 50b for discharging the wash water is formed at the other end (downstream end) of the throat pipe 50.
Furthermore, as shown in FIG. 4, the throat pipe 50 has a pipe shape extending from its suction port 50a to its exhaust port 50b, for example, formed in an inverted U-shape (or, in other words, an inverted J-shape or a gooseneck shape).
Here, the jet nozzle 46 is disposed so as to face the suction port 50a of the throat pipe 50. The suction port 50a of the throat pipe 50 and the jet nozzle 46 are always submerged in the water storage tank body 22.

Also, as shown in Figures 3, 4, 6A and 6B, the flow path switching valve 48 is capable of switching the flow path of the jetted cleaning water to either a toilet flushing flow path 52 that communicates with the toilet body 4, or a tank water storage flow path 54 that communicates with the water storage tank body 22, depending on the water level in the water storage tank body 22.
Specifically, when flushing the bowl portion 6 of the toilet body 4, the suction port 50a of the throat pipe 50 is opened by the flow path switching valve 48, and the flush water jetted from the jet nozzle 46 flows into the suction port 50a of the throat pipe 50 through the toilet flushing flow path 52. The flush water that flows into the throat pipe 50 flows out of the discharge port 50b of the throat pipe 50 and is discharged from the drain port 14 of the flush water tank device 1 to the water conduit 16 side of the toilet body 4.
On the other hand, the tank water storage flow path 54 is a flow path in which, when water is stored in the water storage tank main body 22, the suction port 50a of the throat pipe 50 is closed by the flow path switching valve 48, and the cleaning water jetted from the jet nozzle 46 is directed into the water storage tank main body 22 outside the throat pipe 50 without flowing into the throat pipe 50.

Incidentally, when the flow path switching valve 48 is set to the toilet flushing flow path 52, the jet nozzle 46 jets flush water from the suction port 50a of the throat pipe 50 toward the inside, thereby inducing a so-called "jet pump effect" in which the flow rate of flush water flowing through the throat pipe 50 is increased beyond the flow rate of flush water sprayed from the jet nozzle 46. As a result, flush water at an increased flow rate is supplied from the discharge port 50b of the throat pipe 50 through the drain port 14 toward the water conduit 16 of the toilet body 4.
In addition, the term "jet pump action" used in this specification means that the forceful flow of cleaning water sprayed from the jet nozzle 46 toward the suction port 50a of the throat pipe 50 creates a negative pressure that directly draws in surrounding cleaning water, such as near the suction port 50a of the throat pipe 50, without relying on other mechanical elements such as a pump, and uses this negative pressure to transport the cleaning water in the water storage tank body 22 that has been sucked into the throat pipe 50 toward the toilet body 4.

4 and 5, an overflow pipe 56 extending in the vertical direction is provided inside the water storage tank body 22. This overflow pipe 56 is provided adjacent to the downcomer pipe portion 38b extending in the vertical direction of the throat pipe 50 of the jet pump unit 42, and its lower end is connected to the drain outlet 14.
As a result, when the water level in the water storage tank body 22 rises above the stop water level and exceeds the position of the overflow outlet 56a of the overflow pipe 56, the flushing water flows into the overflow pipe 56 and is supplied as make-up water to the water conduit 16 of the toilet body 4 from the drain outlet 14.
3 to 6B, a make-up water channel (make-up water pipe 58) that connects a portion of the tank storage flow path 54 to the overflow port 56a is provided inside the water storage tank body 22. As a result, a portion of the flush water in the tank storage flow path 54 shown in Fig. 6B flows into the overflow pipe 56 via the make-up water pipe 58, is supplied to the water conduit 16 of the toilet body 4 from the drain port 14, and is ultimately used as make-up water to form a seal in the toilet body 4.

Next, as shown in Figures 4 and 5, the flush water tank device 1 is equipped with a large/small flush switching device 60 provided within the water storage tank main body 22, and this large/small flush switching device 60 makes it possible to switch between either the large flush mode or the small flush mode.
The large/small flush switching device 60 also includes a small tank 62 for switching between large and small flushes, which is provided within the water storage tank body 22 , and a large/small flush switching valve device 64 provided in this small tank 62 .

Next, Fig. 7 is a partial front cross-sectional view showing an enlarged view of the water storage tank main body and small tank of a flush water tank apparatus according to one embodiment of the present invention, and Fig. 8 is a perspective view of the small tank of a flush water tank apparatus according to one embodiment of the present invention, seen from diagonally above and to the front right.
In FIG. 8, a portion of the front wall surface (front partition wall 66a) of the small tank 62 is cut away so that the large/small cleaning switching valve device 64 inside the small tank 62 can be seen.
4 to 8, the small tank 62 has a side wall (partition wall 66) that extends in the vertical direction and partitions the small tank 62 into an external area S1 on the water storage tank body 22 side and an internal area S2 inside the small tank 62. This partition wall 66 forms a wall surface that extends in the vertical direction, and the small tank 62 as a whole is cup-shaped with its upper part open and surrounded on all four sides in the front-to-back and left-to-right directions, and the overall length of the small tank 62 in the left-to-right direction is longer than its overall length in the front-to-back direction.
Incidentally, within the external area S1 of the small tank 62 within the water storage tank body 22, the jet nozzle 46, the suction port 50a of the throat pipe 50, etc. are arranged.

Next, as shown in Figures 4 to 8, the small tank 62, more specifically, comprises a small tank main body 68 extending from one left or right side (right sides in Figures 4, 7 and 8) within the water storage tank main body 22 to the other longitudinal side (left sides in Figures 4, 7 and 8), and a protrusion 70 protruding downward from the lower end of the other side (left sides in Figures 4, 7 and 8) of the small tank main body 68 to the base surface 22a of the water storage tank main body 22.
4 and 8, the overall shape of the small tank is generally L-shaped in front view, extending from one of the left and right sides of the small tank main body 68 (the right side when the small tank main body 68 is viewed from the front) to the other side in the longitudinal direction (the left side when the small tank main body 68 is viewed from the front), and then protruding downward by a protrusion 70, so that the other sidewall in the left-right direction of the small tank main body 68 (the left sidewall when the small tank main body 68 is viewed from the front) and the left partition wall 70b on the other side in the left-right direction of the protrusion 70 form an integral wall surface in the vertical direction. In other words, the overall length of the protrusion 70 in the left-right direction is shorter than the overall length of the small tank main body 68 in the left-right direction.
In addition, the overall shape of the small tank 62 is not necessarily limited to a form in which the left side wall of the small tank main body 68 and the left partition wall 70b in the left-right direction of the protrusion 70 form an integral wall surface in the vertical direction, but may be a roughly L-shaped shape extending from one of the left and right sides of the small tank main body 68 to the other side in the longitudinal direction, then protruding downward by the protrusion 70, and then extending from one of the left and right sides of the small tank main body 68 to the other side in the longitudinal direction.
A switching opening 72 is provided in a partition wall (right partition wall 70a) on one of the left and right sides (the right side in Figs. 4 and 8) of the protruding portion 70.

Furthermore, as shown in Figures 6A, 6B and 7, the water tank main body 22 is provided with a base surface 22a on which the lowest bottom surface 70c of the protrusion 70 of the small tank 62 is located, and a lowest bottom surface 22b within the jet nozzle accommodating section H that protrudes downward in an area on one of the left and right sides of this base surface 22a (the area on the right side when the water tank main body 22 is viewed from the front).
As a result, the protrusion 70 of the small tank 62 is formed so as to protrude downward from the lower end of the small tank main body 68 to the base surface 22 a within the water storage tank main body 22 .

FIG. 9 is a cross-sectional view taken along line XI-XI of FIG.
As shown in FIGS. 4 and 7 to 9, the switching opening 72 of the protruding portion 70 of the small tank 62 is arranged so as to be directed toward the jet nozzle 46 of the jet pump unit 42 and the suction port 50 a of the throat pipe 50 .
In addition, in the area S1 within the water tank body 22 between the switching opening 72 of the small tank 62 and the suction port 50a of the jet nozzle 46 and the throat pipe 50, a straightening area (storage tank body side straightening area R1) is provided which straightens the cleaning water after it is discharged from the switching opening 72 of the small tank 62.

Next, as shown in Figures 4 to 9, the protrusion 70 of the small tank 62 includes a right-side partition wall 70a provided on one side (right side) of the left-right longitudinal direction and having a switching opening 72 formed therein, and a left-side partition wall 70b provided opposite the other side (left side) of the right-side partition wall 70a in the left-right longitudinal direction.
In addition, within the internal region S2 of the small tank 62 formed between the first side wall surface, which is the wall surface of the right side partition wall 70a of the protrusion 70 of each of these small tanks 62, and the second side wall surface, which is the wall surface of the left side partition wall 70b of the protrusion 70, a straightening region (small tank internal straightening region R2) is provided which straightens the cleaning water before it is discharged from the switching opening 72 in the small tank 62.
Furthermore, the small tank internal flow straightening region R2 has a maximum width dimension L1 [mm] in the left-right direction that is set to be larger than a maximum width dimension W1 [mm] in the front-rear direction (L1>W1).

In addition, as shown in Figures 5 and 9, the maximum width dimension W1 in the front-to-rear short direction of the protrusion 70 of the small tank 62 is set to be smaller than the maximum width dimension W2 of each of the maximum width dimensions when the maximum width dimension of the internal area of the water storage tank body 22 is divided in half in the short direction (W1 < W2).

Next, as shown in FIGS. 4 and 7, the switching opening 72 of the small tank 62 is disposed above the suction port 50 a of the throat pipe 50 .
As shown in FIG. 9, the water tank body 22 has a longitudinal center axis C1 that bisects the maximum front-to-rear width dimension of the internal region S2 into a front region F0 and a rear region B0, and a transverse center axis C2 that bisects the maximum left-to-right width dimension of the internal region S2 into a left-to-right side region (right region R0) and a right-to-left side region (left region L0).
Furthermore, as shown in Figure 9, the protrusion 70 of the small tank 62 is located in a region (left side region L0) on one side of the short side center axis C2 of the water storage tank body 22 (right side region R0) where the suction port 50a of the throat pipe 50 is located, relative to a region on the other side of the short side center axis C2 (left side) where the suction port 50a is not located.
In addition, the protruding portion 70 of the small tank 62 is disposed in a region (front region F0) on the other side of the longitudinal central axis C1 of the water storage tank body 22 where the center O1 of the drain outlet 14 (center O1 of the outlet 50b of the throat pipe 50) is not disposed, relative to a region (rear region B0) on the other side of the longitudinal central axis C1 of the water storage tank body 22 where the center O1 of the drain outlet 14 of the water storage tank body 22 (center O1 of the outlet 50b of the throat pipe 50) is disposed. As a result, the protruding portion 70 of the small tank 62 is disposed so as to be spaced apart from the suction port 50a of the throat pipe 50.

Next, as shown in Figure 9, the switching opening 72 is located within the water tank body 22 in a region (left region L0) on the other side of the short side center axis C2 where the suction port 50a of the throat pipe 50 is not provided, compared to a region (right region R0) on the left or right side of the short side center axis C2 where the suction port 50a is provided, and is located in a region (front region F0) forward of the longitudinal center axis C1.
9, the switching opening 72 has a central axis C3 that passes through the center O2 of the opening cross section and extends in the left-right longitudinal direction of the water storage tank body 22. The central axis C3 of the switching opening 72 is disposed to be spaced apart from the central axis C4 of the throat pipe 50 in the longitudinal direction to one side (front side) in the front-rear direction of the water storage tank body 22 in the plan view of FIG.

Next, the large/small flush switching valve device 64 will be described in detail with reference to FIGS. 4, 5, 7, 8, 10, and 11A to 11D.
First, Figure 10 is a partially enlarged perspective view showing an enlargement of the large/small flush switching valve device portion of the flush water tank apparatus according to one embodiment of the present invention shown in Figure 8. Also, Figures 11A to 11D are partially enlarged views showing an enlargement of the large/small flush switching valve device portion in the flush water tank apparatus according to one embodiment of the present invention.
In particular, Fig. 11A shows the open state of the switching valve body of the large/small flush switching valve device in the standby state before the start of the toilet flush operation and when the large flush operation of the toilet has begun. Fig. 11B shows the closed state of the switching valve body of the large/small flush switching valve device when the small flush operation of the toilet has begun. Fig. 11C shows the closed state of the switching valve body of the large/small flush switching valve device during a small flush of the toilet. Fig. 11D shows the state in which the switching valve body of the large/small flush switching valve device in the closed state has opened after the small flush of the toilet has ended and water is being supplied from the water supply valve device to the water storage tank main body.

As shown in Figures 4, 5, 7, 8, 10, and 11A to 11D, the large/small flush switching valve device 64 includes a switching valve body 74, a swinging member 76, a ball chain 78, and a pull-up lever 80.
First, as shown in FIGS. 10 to 11D, a bottom surface 68a of the small tank main body 68 is provided with a pair of support portions 68b arranged in pairs in the front-rear direction and protruding upward.
Furthermore, hinge protrusions 68c that protrude in the front-rear direction are provided on the surfaces of the support portions 68b that face each other in the front-rear direction.
The switching valve body 74 of the large/small flush switching valve device 64 is provided with a pair of supported parts 74a arranged in a pair in the front-rear direction and supported by each of the support parts 68b of the small tank main body 68. Each of the supported parts 74a is provided with a hinge hole 74b that can be connected to each of the hinge protrusions 68c.
That is, each hinge protrusion 68c and each hinge hole 74b is provided near the upper portion of the switching opening 72 and serves as a hinge portion that allows the switching valve body 74 to rotate. This allows the switching valve body 74 to rotate about the central axis in the front-rear direction of each hinge protrusion 68c and the central axis of each hinge hole 74b (hinge axis C5), allowing the switching valve body 74 to be opened and closed relative to the switching opening 72.
The switching valve body 74 opens and closes the switching opening 72, thereby changing the amount of flush water supplied to the toilet body 4 through the jet pump unit 42, making it possible to switch between a large flush and a small flush.

Next, as shown in FIGS. 10 to 11D, the swinging member 76 of the large/small flush switching valve device 64 is provided swingably about a swinging shaft 74c that protrudes forward and backward from the switching valve body 74.
When the switching valve body 74 is in an open state with the switching valve body 74 in a substantially horizontal position, the swinging member 76 is disposed on the bottom surface 68a of the small tank main body 68 so as to support the switching valve body 74 from below.
In addition, one end of a ball chain 78 is connected to a part of the swinging member 76 .
11A to 11B, the pull-up lever 80 of the large/small flush switching valve device 64 is connected to the drive rotation shaft 32b of the operation device 32. In addition, the other end of the ball chain 78 is connected to a part of the pull-up lever 80.

As a result, the switching valve body 74 of the large/small flush switching valve device 64 is connected to the drive rotation shaft 32 b of the water supply valve device 28 via the swinging member 76 , the ball chain 78 , and the pull-up lever 80 .
For example, as shown in FIG. 11A, in the standby state before the start of the toilet flushing operation, the ball chain 78 is in a slack state, and the switching valve body 74 is in a horizontal position, opening the switching opening 72.
As shown in FIG. 11A, when the large-flush operation of the toilet has started, the user rotates the operating lever 32a in one direction, and the drive rotation shaft 32b is rotated in one direction.
However, since the pull-up lever 80 does not rotate integrally with the drive shaft 32b and remains stationary, the ball chain 78 is not pulled up by the pull-up lever 80 and remains slack. As a result, the switching valve body 74 maintains the switching opening 72 open.

Next, as shown in FIG. 11B, when the small flush operation of the toilet has started, the user rotates the operating lever 32a in the other direction, and the drive rotation shaft 32b is rotated in the other direction.
As a result, the pull-up lever 80 rotates integrally with the drive rotation shaft 32 b , and the ball chain 78 is pulled up by the pull-up lever 80 .
When the ball chain 78 is pulled up, the oscillating member 76 swings around the oscillating axis 74c of the switching valve body 74 so that its tip rises, and the switching valve body 74 and the oscillating member 76 as a whole assume an upright position.
In addition, the switching valve body 74 is in a state where the switching opening 72 is closed by being in this upright position.
At this time, as shown in Figure 11B, the water level WL1 in the water storage tank body 22 in the external area S1 of the small tank 62 is lower than the water level WL2 in the internal area S2 of the small tank 62, and the water pressure P2 in the internal area S2 of the small tank 62 is higher than the water pressure P2 in the water storage tank body 22 in the external area S1 of the small tank 62 (P2 > P1), so that the water level difference ΔWL (= WL2 - WL1) and the water pressure difference ΔP (= P2 - P1) cause the switching valve body 74 to be maintained in a closed state.

Next, as shown in FIG. 11C, during a small flush of the toilet, the pull-up lever 80 rotates to return to its original state before it was pulled up (the standby state in FIG. 11A), and the drive rotation shaft 32b also rotates in one direction together with the pull-up lever 80.
At this time, the swinging member 76 also swings in a direction returning to the standby state independently of the switching valve body 74, and assumes a horizontal position.
At this time, as shown in Figure 11C, the water level WL1 in the water storage tank body 22 in the external area S1 of the small tank 62 is lower than the water level WL2 in the internal area S2 of the small tank 62, and the water pressure P2 in the internal area S2 of the small tank 62 is higher than the water pressure P2 in the water storage tank body 22 in the external area S1 of the small tank 62 (P2 > P1), so that the water level difference ΔWL (= WL2 - WL1) and the water pressure difference ΔP (= P2 - P1) cause the switching valve body 74 to be maintained in a closed state.
In addition, during a small flush of the toilet, the oscillating member 76 rotates (oscillates) independently of the switching valve body 74, thereby preventing the ball chain 78 itself from interfering with the switching valve body 74 and causing it to open, and the switching valve body 74 is maintained in a closed state.
8, a small communication hole 68d is provided in the bottom surface 68a on one of the left and right sides (the right side when the small tank body 68 is viewed from the front) of the small tank body 68, which connects the internal area S2 of the small tank 62 with the external area S1 (inside the water storage tank body 22). As a result, the water level WL2 of the flush water in the small tank 62 drops slightly when the switching opening 72 is closed by the switching valve body 74, but is still higher than the water level WL1 in the water storage tank body 22 (WL2>WL1) (see FIG. 11C).
Incidentally, during the full-flush operation of the toilet, flush water present in a position far from the switching opening 72 in the small tank 62 is discharged from the small communicating hole 68d into the external area S1 of the small tank 62, thereby making it possible to reduce the amount of flush water remaining in the small tank 62.

Next, as shown in FIG. 11D, when the water level WL1 of the flush water in the water storage tank body 22 drops to the water level DWL1, the flow path switching valve 48 switches to the water storage flow path 54, the flush water of the jet nozzle 46 switches from supplying water to the throat pipe 50 to supplying water to the water storage tank body 22, the small flush of the toilet is completed, and water is supplied to the water storage tank body 22.
As a result, the water level WL1 in the external area S1 of the small tank 62 (the water level in the water storage tank body 22) rises and becomes the same water level as the water level WL2 of the cleaning water in the small tank 62 (WL1 = WL2), and the water level difference ΔWL (= WL2 - WL1) and the water pressure difference ΔP (= P2 - P1) become 0.
At this time, since the switching valve element 74 is provided with a weight 74d (see FIGS. 10 and 11D) on the side of the swinging member 76, the balance between the weight of this weight 74d and the center of gravity of the switching valve element 74 is adjusted in the direction of the open valve state. As a result, the switching valve element 74 rotates to a horizontal position and is in the open valve state.
In addition, since a weight 74d is provided on the switching valve body 74, when the cleaning water in the small tank 62 is discharged from the switching opening 72 to the external area S1 of the small tank 62 during the large flush operation, the flow of the cleaning water in the small tank 62 prevents the switching valve body 74 from mistakenly entering a closed state.
Furthermore, as shown in FIG. 6B, within the jet nozzle accommodating section H of the water storage tank main body 22, the flow path switching valve 48 is switched to the tank water storage flow path 54, so that the cleaning water jetted from the jet nozzle 46 is supplied into the water storage tank main body 22 without flowing into the throat pipe 50.

As shown in FIG. 4, the water level WL in the water storage tank body 22 is at the following position.
First, the water level DWL1 indicates the lowest water level in the area S1 in the water tank body 22 when each of the large and small flushes of the toilet is completed, as shown in Figure 4, and is located below the lower end of the switching opening 72.
Next, as shown in FIG. 4, the water level DWL1 is the lowest water level in the area S1 in the water storage tank body 22 when each of the large and small flushes is completed, and the water level DWL2 indicates the lowest water level in the area S2 in the small tank 62 when the small flush is completed.
4, the water level WL0 is the stop water level (highest water level) in the initial state (standby state) of flush water stored in the storage tank body 22. This stop water level WL0 indicates the normal stop water level before or after use of the flush toilet 2, and is located slightly above the water level DWL2.
Incidentally, the water level WL1 shown in FIG. 4 is the water level in the area S1 in the water storage tank body 22 when the water level is decreasing or increasing, and is higher than the minimum water level DWL1 and lower than the maximum water level WL0.
The water level WL2 shown in FIG. 4 is the water level in the area S2 in the small tank 62 when the water level is decreasing or increasing, and is higher than the minimum water level DWL2 and lower than the maximum water level WL0.

Next, the operation of the flush water tank assembly 1 according to one embodiment of the present invention will be described with reference to FIGS.
FIG. 12 is a flow chart showing the flow of operation of a flush water tank assembly according to one embodiment of the present invention.
As shown in FIG. 12, when performing either the large flush or small flush of the flush toilet 2, first, in step S1, the user rotates the operating lever 32a of the operating device 32.
Specifically, when the operating lever 32a is rotated in one direction (for example, toward the front (large flush side) when looking at the flush water tank device 1 from the front), the large flush mode is started, and when the operating lever 32a is rotated in the other direction (for example, toward the rear (small flush side) when looking at the flush water tank device 1 from the front), the small flush mode is started.

Next, the large flush mode will be described below.
When the large flush mode is started, the drive rotation shaft 32b of the operating device 32 is rotated in one direction by rotating the operating lever 32a, but the lifting lever 80 of the large/small flush switching valve device 64 remains stationary and does not rotate integrally with the drive rotation shaft 32b.
As a result, the ball chain 78 is not pulled up by the pull-up lever 80 and is in a slack state, so that the swinging member 76 is not pulled up by the ball chain 78 .
In addition, the weight of the weight 74d of the switching valve body 74 causes the switching valve body 74 to assume a substantially horizontal position on the swinging member 76, and the swinging member 76 is pressed against the bottom surface 68a of the small tank main body 68. This causes the switching valve body 74 to maintain the switching opening 72 open (see FIG. 11A).

Next, in step S2 of FIG. 12, the poppet valve 34 of the water supply valve device 28 is opened by the rotation of the drive rotation shaft 32b of the operating device 32 in one direction.
At this time, the water storage tank body 22 is filled with flushing water near the stop water level (highest water level) WL0, so the flow path switching valve 48 of the jet pump unit 42 is switched to the toilet flushing flow path 52 due to the buoyancy of the flushing water in the water storage tank body 22, and the suction port 50a of the throat pipe 50 is opened by the flow path switching valve 48.
Then, in step S4 of FIG. 12, when the poppet valve 34 of the water supply valve device 28 opens, in step S4, wash water flows out of the pressure chamber 30c of the water supply valve device 28, and the pressure in the pressure chamber 30c decreases.
As a result, the main valve body 30a of the water supply valve (main valve 30) of the water supply valve device 28 moves away from the main valve seat 30b, opening the valve, and the cleaning water supplied to the water supply valve device 28 from the water supply pipe 24 via the constant flow valve 26 is supplied from the water supply valve device 28 into the water supply pipe 44 downstream.
Thereafter, the flushing water in the water supply pipe 44 is supplied to the jet nozzle 46 of the jet pump unit 42 via the vacuum breaker valve 40. The flushing water supplied to this jet nozzle 46 is sprayed toward the suction port 50a of the throat pipe 50 via the toilet flushing flow path 52 of the flow path switching valve 48, and jet spouting begins (see FIG. 6A).
In addition, when jet water spouting begins, the forceful flow of cleaning water sprayed from the jet nozzle 46 toward the suction port 50a of the throat pipe 50 creates a negative pressure that directly draws in the surrounding cleaning water, such as near the suction port 50a of the throat pipe 50, without relying on other mechanical elements such as a pump, and this negative pressure is used to transport the cleaning water in the water storage tank body 22 that has been sucked into the throat pipe 50 toward the toilet body 4, creating a so-called "jet pump action."

Furthermore, if the jet water spouting continues, in step S5 of FIG. 12, the water level WL1 in the water storage tank body 22 drops, causing the float 36 of the water supply valve device 28 to descend and the float-side pilot valve 38 to open.
At this time, since the internal area S2 of the small tank 62 and the external area S1 (area S1 within the water storage tank body 22) are connected via the open switching opening 72 and the small communicating hole 68d of the small tank 62, the water level WL2 within the small tank 62 also decreases together with the water level WL1 within the water storage tank body 22.
When the water level WL1 in the water storage tank main body 22 and the water level WL2 in the small tank 62 drop to the minimum water level DWL1, the buoyancy caused by the cleaning water in the water storage tank main body 22 acting on the flow path switching valve 48 of the jet pump unit 42 also decreases.
As a result, the flow path switching valve 48 of the jet pump unit 42 is switched to the tank water storage flow path 54, and the suction port 50a of the throat pipe 50 is closed by the flow path switching valve 48 (see Figure 6B).
Therefore, flush water jetted from the jet nozzle 46 is supplied into the water storage tank body 22 from the tank water storage flow path 54 of the flow path switching valve 48. At the same time, a portion of this flush water is replenished from the make-up water pipe 58 into the overflow pipe 56, and then replenished to the toilet body 4 side.
This flush water supplied to the toilet body 4 is used when forming a water seal in the toilet body 4.

12, when the water level WL1 in the water storage tank body 22 rises due to water supply from the tank water storage flow path 54 of the flow path switching valve 48 into the water storage tank body 22, the float 36 of the water supply valve device 28 rises due to the buoyancy of the flush water at the rising water level WL1, and the float-side pilot valve 38 closes. Since the small tank 62 is connected through the opened switching opening 72 and the small communication hole 68d, the water level WL2 in the small tank 62 also rises together with the water level WL1 in the water storage tank body 22.
As a result, the pressure in the pressure chamber 30c of the water supply valve device 28 again becomes the primary flow path pressure α, causing the main valve body 30a to move toward the main valve seat 30b, and ultimately causing the main valve 30 to close (stop water flow).
At this time, in step S8 of Figure 12, since the water storage tank body 22 is filled with flushing water at the stop water level (highest water level) WL0, the flow path switching valve 48 of the jet pump unit 42 is again switched to the toilet flushing flow path 52 due to the buoyancy of the flushing water in the water storage tank body 22, and the suction port 50a of the throat pipe 50 is opened by the flow path switching valve 48.
Then, in step S9 of FIG. 12, water storage in the water storage tank body 22 is completed, whereby the large-flush mode is completed and the device goes into a standby state (see FIG. 11A).

Next, the small cleaning mode will be described below.
First, in step S1 of FIG. 12, when the small-flush mode has been started, the drive rotation shaft 32b of the operation device 32 is rotated in the other direction by rotating the operation lever 32a.
Then, in step S2 of Figure 12, the poppet valve 34 of the water supply valve device 28 opens, the flow path switching valve 48 of the jet pump unit 42 is switched to the toilet flushing flow path 52, and the suction port 50a of the throat pipe 50 is opened by the flow path switching valve 48.

Next, in step S3 of FIG. 12, the pull-up lever 80 of the large/small flush switching valve device 64 moves in conjunction with the drive rotation shaft 32b (rotates integrally with the drive rotation shaft 32b), and the ball chain 78 is pulled up by the pull-up lever 80.
Then, as the ball chain 78 is pulled up, the oscillating member 76 oscillates around the oscillating axis 74c of the switching valve body 74 so that its tip rises, and the switching valve body 74 and the oscillating member 76 as a whole assume an upright position (see Figure 11B).
Moreover, the switching valve body 74 is in a state where it closes the switching opening 72 by being in a vertically raised position.

Next, as in the large-flush mode, in step S4 of FIG. 12, the water supply valve (main valve 30) of the water supply valve device 28 opens, cleaning water is sprayed from the jet nozzle 46 toward the suction port 50a of the throat pipe 50, and jet spouting begins (see FIG. 6A).
Then, as in the large-flush mode, in step S5 of FIG. 12, as the jet water spouting continues, the water level WL1 in the water tank body 22 drops, causing the float 36 of the water supply valve device 28 to descend and the float-side pilot valve 38 to open.

At this time, as shown in Figures 11B and 11C, the water level WL1 in the water storage tank body 22 of the external area S1 of the small tank 62 is lower than the water level WL2 in the internal area S2 of the small tank 62, and the water pressure P2 in the internal area S2 of the small tank 62 is higher than the water pressure P2 in the water storage tank body 22 of the external area S1 of the small tank 62 (P2>P1).The water level difference ΔWL (=WL2-WL1) and the water pressure difference ΔP (=P2-P1) maintain the switching valve body 74 in a closed state.

Next, in step S6 of FIG. 12, when the water level WL1 in the water storage tank body 22 further drops to the minimum water level DWL1 and the water level WL2 in the small tank 62 drops to the minimum water level DWL2, the small flush of the toilet ends (see FIG. 11D).
At this time, as shown in Figure 6B, in the jet nozzle housing section H of the water storage tank body 22, the flow path switching valve 48 is switched to the tank water storage flow path 54, so that flush water jetted from the jet nozzle 46 is supplied into the water storage tank body 22 without flowing into the throat pipe 50. At the same time, a portion of this flush water is replenished from the make-up water pipe 58 into the overflow pipe 56, and then replenished to the toilet body 4 side.
Thereafter, as water is further supplied into the water storage tank body 22, the water level WL1 in the external area S1 of the small tank 62 (the water level in the water storage tank body 22) rises, and the water level WL2 of the flush water in the small tank 62 and the water level WL1 in the water storage tank body become the same water level (WL1=WL2). As a result, the water level difference ΔWL (=WL2-WL1) and the water pressure difference ΔP (=P2-P1) become zero, and the water level difference and water pressure difference that keep the switching valve body 74 in the closed state disappear, so that the switching valve body 74 rotates toward the swinging member 76 so as to assume a horizontal position due to the balance between the weight of the weight 74d (see Figures 10 and 11D) on the swinging member 76 side and the center of gravity of the switching valve body 74, and the valve is opened.

12, the water level WL1 in the water storage tank body 22 rises due to water being supplied from the tank water storage flow path 54 of the flow path switching valve 48 into the water storage tank body 22, and the float 36 of the water supply valve device 28 rises due to the buoyancy caused by the flush water at this raised water level WL1, closing the float-side pilot valve 38. This closes the main valve 30 of the water supply valve device 28, and the water supply is stopped.
At this time, since the small tank 62 is in communication with the open switching opening 72 and the small communication hole 68d, the water level WL2 in the small tank 62 also rises together with the water level WL1 in the water storage tank body 22.
Furthermore, as in the large-flush mode, in step S8 of FIG. 12, the water storage tank body 22 is filled with flush water at the stop water level (highest water level) WL0, so that the flow path switching valve 48 of the jet pump unit 42 is again switched to the toilet flushing flow path 52 due to the buoyancy of the flush water in the water storage tank body 22, and the suction port 50a of the throat pipe 50 is opened by the flow path switching valve 48.
Then, in the same manner as in the large-flush mode, when water storage in the water storage tank body 22 is completed in step S9 in FIG. 12, the small-flush mode is completed and the standby state is entered (see FIG. 11A).

Next, the operation of the flush water tank apparatus 1 according to one embodiment of the present invention will be described with reference to FIGS.
According to the flush water tank device 1 of one embodiment of the present invention described above, for example, when the operating lever 32a and drive rotating shaft 32b of the operating device 32 are rotated to start a large flush of the toilet body 4 of the flush toilet 2, the poppet valve 34 of the water supply valve device 28 opens, the water supply valve (main valve 30) opens, the switching valve body 74 of the large/small flush switching valve device 64 enters an open state, and the switching opening 72 of the small tank 62 for switching between large and small flushes is opened.
As a result, wash water supplied from a water supply source (not shown) passes through the water supply valve (main valve 30) of the water supply valve device 28 and is supplied to the jet nozzle 46 of the jet pump unit 42. Then, wash water is sprayed from the jet nozzle 46 toward the suction port 50a of the throat pipe 50, inducing a jet pump action in the water storage tank body 22.
Furthermore, due to this jet pump action, the forceful flow of flush water sprayed from the jet nozzle 46 toward the suction port 50a of the throat pipe 50 creates a negative pressure that directly draws in surrounding flush water, such as near the suction port 50a of the throat pipe 50, without relying on other mechanical elements such as a pump. Then, flush water in the water storage tank body 22 that has been sucked into the throat pipe 50 is pressure-fed toward the toilet body 4 by this negative pressure. As a result, a large volume of flush water is supplied from the water storage tank body 22 to the toilet body 4, and a large flush toilet flush is performed in the toilet body 4.
In this case, the overall shape of the small tank 62, which extends from one of the left and right sides of the small tank main body 68 to the other side in the longitudinal direction and then protrudes downward by the protrusion 70, is generally L-shaped when viewed from the front. Therefore, the entire small tank 62 can be made smaller while making effective use of the longitudinal space within the water storage tank main body 22, compared to a small tank 62 that is generally rectangular in shape when viewed from the front.
In addition, the protruding portion 70 of the small tank 62 itself protrudes downward from the lower end (bottom surface 68a) of the small tank main body 68, and is disposed on the bottom surface (base surface 22a) side of the water storage tank main body 22. This allows the switching opening 72 provided on one of the left and right sides of the protruding portion 70 to be located close to the bottom surface (base surface 22a) of the water storage tank main body 22.
This allows the cleaning water W discharged from the switching opening 72 of the small tank 62 into the water storage tank body 22 in the external area S1 of the small tank 62 to flow smoothly within the area S1 on the bottom side (base surface 22a) of the water storage tank body 22.
Furthermore, the entire small tank 62 formed by the small tank body 68 and the protruding portion 70 is formed in a generally L-shape when viewed from the front. This allows the area S1 between the small tank body 68 and the bottom surface (base surface 22a) inside the water storage tank body 22 other than the protruding portion 70 to be effectively used as a storage space capable of storing flush water.
Furthermore, the area S1 (storage space) other than the protruding portion 70 between the bottom surface 68a of the small tank main body 68 and the bottom surface (base surface 22a) inside the water storage tank main body 22 can also be used as a rectification area (water storage tank main body side rectification area R1) that rectifies the flush water discharged from the switching opening 72 of the small tank 62. This makes it possible to improve the rectification of the flush water throughout the water storage tank main body 22 while realizing the miniaturization of the small tank 62 and the water storage tank main body 22 as a whole.
As a result, the flow straightening of the flushing water throughout the water storage tank body 22 can be improved, making it possible to achieve both miniaturization of the small tank 62 and the entire water storage tank body 22, and improved supply performance of the flushing water supplied from the water storage tank body 22 to the toilet body 4 and improved toilet flushing performance.

In addition, according to the cleaning water tank device 1 of this embodiment, the cleaning water stored in the area on the discharge port 50b side of the throat pipe 50 of the jet pump unit 42 within the water storage tank main body 22 flows toward the suction port 50a side, avoiding the discharge port 50b of the throat pipe 50, due to the suction force from the suction port 50a side of the throat pipe 50 caused by the jet pump action.
At this time, if the protruding portion 70 of the small tank 62 is arranged in an area R0 on one side (the right side when looking at the water tank body 22 from the front side) of the short-side central axis C2 of the water tank body 22 where the suction port 50a of the throat pipe 50 is arranged, or if the protruding portion 70 of the small tank 62 is arranged in an area B0 on one side (the rear side) of the long-side central axis C1 of the water tank body 22 where the center O1 of the discharge port 50b of the throat pipe 50 is arranged, the distance from the switching opening 72 of the small tank 62 to the suction port 50a of the throat pipe 50 becomes too short. As a result, it becomes difficult to secure a rectification area (storage tank body side rectification area R1) in the water tank body 22 that rectifies the flush water W discharged from the switching opening 72 of the small tank 62, and the rectification of the flush water in the entire water tank body 22 decreases.
Furthermore, if the flow straightness of the flushing water throughout the water storage tank body 22 decreases, the flushing water W discharged from the switching opening 72 of the small tank 62 will not be supplied smoothly to the suction port 50a side of the throat pipe 50, which may result in residual water being generated in the small tank 62 or a decrease in the supply performance of the flushing water supplied from the water storage tank body 22 to the toilet body 4 and in the toilet flushing performance.
In contrast, according to the flush water tank device 1 of this embodiment, the protruding portion 70 of the small tank 62 is disposed in a region L0 on the other left or right side (left side as viewed from the front side of the water storage tank body 22) of the short-side central axis C2 of the water storage tank body 22, where the suction port 50a of the throat pipe 50 is disposed, relative to a region R0 on one side (right side as viewed from the front side of the water storage tank body 22) of the short-side central axis C2 of the water storage tank body 22 where the suction port 50a of the throat pipe 50 is disposed, in a region L0 on the other side (left side as viewed from the front side of the water storage tank body 22) of the short-side central axis C2 of the water storage tank body 22, where the suction port 50a of the throat pipe 50 is disposed. Furthermore, the protruding portion 70 of the small tank 62 is disposed in a region F0 on the other side (front side) of the longitudinal central axis C1 of the water storage tank body 22, where the center O1 of the drain port 14 (center O1 of the discharge port 50b of the throat pipe 50) is not disposed, relative to a region B0 on one side (rear side) of the longitudinal central axis C1 of the water storage tank body 22 where the center O1 of the discharge port 50b of the throat pipe 50 is disposed. As a result, the area S1 other than the protrusion 70 between the bottom surface 68a of the small tank main body 68 and the bottom surface (base surface 22a) of the water storage tank main body 22 can also be effectively utilized as storage space for storing cleaning water.
In addition, such storage space can also be used as a straightening area (straightening area R1 on the water storage tank body side) that straightens the cleaning water W discharged from the switching opening 72 of the small tank 62, thereby making it possible to improve the straightening of the cleaning water throughout the water storage tank body 22 while reducing the size of the small tank 62 and the entire water storage tank body 22.
As a result, the flow straightening of the flushing water throughout the water storage tank body 22 can be improved, making it possible to achieve both miniaturization of the small tank 62 and the entire water storage tank body 22 while also achieving good supply performance of the flushing water supplied from the water storage tank body 22 to the toilet body 4 and good toilet flushing performance.

Furthermore, according to the cleaning water tank device 1 of this embodiment, the protrusion 70 of the small tank 62 is formed so as to protrude from the lower end (bottom surface 68a) of the small tank main body 68 to the bottom surface (base surface 22a) within the water storage tank main body 22 which is located below this lower end (bottom surface 68a), thereby ensuring the largest possible volume within the small tank 62.
In addition, by projecting the protruding portion 70 of the small tank 62 to the bottom surface (base surface 22a) of the water storage tank body 22, it is possible to reduce the space between the bottom surface of the entire small tank 62 and the bottom surface (base surface 22a) of the water storage tank body 22. This also makes it possible to reduce the residual water space in the distal region separated from the suction port 50a of the throat pipe 50 in the water storage tank body 22.
Therefore, the suction force from the suction port 50a side of the throat pipe 50 is easily spread over the entire flush water in the water storage tank body 22 by the jet pump action, and the entire flush water in the water storage tank body 22 is easily supplied to the suction port 50a of the throat pipe 50. This improves the supply performance of the flush water supplied from the water storage tank body 22 to the toilet body 4, and therefore improves the toilet flushing performance.

Furthermore, according to the flush water tank apparatus 1 of this embodiment, the protrusion 70 of the small tank 62 is formed so as to protrude downward from the lower end (bottom surface 68a) of the small tank main body 68 to the base surface 22a within the water storage tank main body 22. Furthermore, in region R0 on one of the left and right sides of the base surface 22a of the water storage tank main body 22 (the right side when viewed from the front side of the water storage tank main body 22), a jet nozzle accommodating section H that can accommodate the jet nozzle 464 is formed so as to protrude downward.
As a result, the cleaning water W discharged from the switching opening 72 of the small tank 62 into the water storage tank main body 22 in the external area S1 of the small tank 62 is straightened while flowing within the space between the bottom surface 68a of the small tank main body portion 68 and the base surface 22a within the water storage tank main body 22 (water storage tank main body side straightening area R1), and then flows toward the jet nozzle 46 of the jet nozzle accommodating portion H and the suction port 50a of the throat pipe 50.
Therefore, the flow straightening of the flushing water throughout the water storage tank body 22 can be improved, and all of the flushing water within the water storage tank body 22 can be more easily supplied to the suction port 50a of the throat pipe 50, thereby improving the supply performance of the flushing water supplied from the water storage tank body 22 to the toilet body 4 and the toilet flushing performance.

Furthermore, according to the cleaning water tank device 1 of this embodiment, a flow path switching valve 48 of the jet pump unit 42, which enables switching of the flow path of the cleaning water sprayed from the jet nozzle 46, is provided within the jet nozzle accommodating section H in the water storage tank main body 22.
This makes it possible to concentrate some of the related elements of the jet pump unit 42 (jet nozzle 46, flow path switching valve 48) within the jet nozzle accommodating portion H.
Therefore, the entire water storage tank body 22 can be made smaller, and the supply performance of the flushing water supplied from the water storage tank body 22 to the toilet body 4 can be further improved in the limited space within the water storage tank body 22.

In addition, according to the cleaning water tank device 1 of this embodiment, the upstream side of the make-up water passage (make-up water pipe 58), which enables a portion of the cleaning water sprayed from the jet nozzle 46 to be supplied as make-up water into the overflow pipe 56, is connected to the jet nozzle accommodating section H.
As a result, when the flow path switching valve 48 is switched to a water supply path (tank water storage flow path 54) that supplies water to the water storage tank body 22 other than the suction port 50a of the throat pipe 50, a portion of the cleaning water sprayed from the jet nozzle 46 can be replenished to the supply water path (supply water pipe 58).
Therefore, some of the related elements of the jet pump unit 42 (jet nozzle 46, flow path switching valve 48, and the upstream side of the make-up water pipe 58) can be concentrated within the jet nozzle accommodating section H, making it possible to reduce the size of the entire water tank body.
Furthermore, in the limited space inside the water storage tank body 22, the supply performance of flush water supplied from the water storage tank body 22 to the toilet body 4 can be further improved.

Furthermore, according to the flush water tank device 1 of this embodiment, the switching opening 72 of the small tank 62 is provided on one side of the protrusion 70 in the left-right longitudinal direction (the right side when looking at the protrusion 70 of the small tank 62 from the front side).
This allows the cleaning water W in the small tank 62 to be pre-rectified in the region in the left and right longitudinal directions of the protrusion 70 (the flow rectification region R2 in the small tank) before being discharged from the switching opening 72.
Therefore, even if the opening cross-sectional area of the switching opening 72 of the small tank 62 is not set large, the cleaning water in the small tank 62 can be straightened in advance in the straightening area R2 within the small tank without being retained in the protrusion 70, and then can be smoothly and stably discharged from the switching opening 72 toward the suction port 50a of the throat pipe 50 in the water storage tank main body 22.
This makes it possible to reduce the amount of residual water in the small tank 62, and to straighten the flow of the cleaning water W discharged from the switching opening 72 of the small tank 62 and heading toward the vicinity of the suction port 50a of the throat pipe 50.
Therefore, the main flow of the main flushing water in the water storage tank body 22, which has been stored in advance in the external area S1 of the small tank 62, flows toward the suction port 50a of the throat pipe 50, and the flushing water W discharged from the switching opening 72 of the small tank 62 can be pre-rectified in the flow straightening area R2 within the small tank and merged in a stable state.
As a result, the flow regulation of the flush water throughout the water storage tank body 22 can be improved, and the supply performance of the flush water supplied from the water storage tank body 22 to the toilet body 4 can be improved.

In addition, according to the flushing water tank device 1 of this embodiment, the maximum width dimension W1 in the front-to-rear short direction of the protrusion 70 of the small tank 62 is set to be smaller than the maximum width dimension W2 of each of the internal areas of the water storage tank main body 22 when divided into two equal parts in the short direction (W1 < W2).
This makes it possible to ensure a water storage area in the front-to-rear direction in the external area S1 of the small tank 62 within the water storage tank body 22 while reducing the overall size of the water storage tank body 22.
Therefore, a relatively large distance can be secured for the flush water in the water storage area in the front-to-rear direction in the outer area S1 of the small tank 62 to be sucked into the suction port 50a of the throat pipe 50, improving flow straightening.
Therefore, in the limited space within the water storage tank body 22, the flow straightening of the flushing water throughout the water storage tank body 22 can be improved, and the supply performance of the flushing water supplied from the water storage tank body 22 to the toilet body 4 can be improved.

Furthermore, according to the flushing water tank device 1 of this embodiment, the protrusion 70 of the small tank 62 can be provided within the water storage tank main body 22, in an area R0 on one side (the right side when viewed from the front) of the short side center axis C2 of the water storage tank main body 22 where the suction port 50a of the throat pipe 50 is provided, and in an area L0 on the other side (the left side when viewed from the front) of the short side center axis C2 of the water storage tank main body 22 where the suction port 50a of the throat pipe 50 is not provided.
Furthermore, the protruding portion 70 of the small tank 62 can be provided in the region F0 on the front side with respect to the longitudinal center axis C1 of the water storage tank body 22.
As a result, the protruding portion 70 of the small tank 62 can be disposed so as to be spaced apart from the suction port 50 a of the throat pipe 50 .
Therefore, the external area (water storage area) S1 of the small tank 62 in the water storage tank body 22 , which is located at a long distance from the suction port 50 a of the throat pipe 50 , can be reduced by the protrusion 70 of the small tank 62 .
In addition, the volume of the area B0 rearward of the longitudinal center axis C1 within the water storage tank body 22, which is at a distance from the suction port 50a of the throat pipe 50, is also reduced by the amount that the external area S1 of the small tank 62 within the water storage tank body 22 is reduced by the protrusion 70 of the small tank 62 in the area F0 forward of the longitudinal center axis C1 within the water storage tank body 22.
Therefore, the distance that the cleaning water stored in area S1 of the water storage tank body 22, which is located a long distance from the suction port 50a of the throat pipe 50, flows when it is sucked toward the suction port 50a, can also be shortened by the amount reduced by the protrusion 70 of the small tank 62.
Therefore, the pressure loss when the entire flush water in the water storage tank body 22 is sucked into the suction port 50a of the throat pipe 50 can be reduced, and the water can flow smoothly to the suction port 50a of the throat pipe 50.
As a result, it becomes easier for all of the flush water in the water storage tank body 22 to be supplied to the suction port 50a of the throat pipe 50, improving the supply performance of flush water supplied from the water storage tank body 22 to the toilet body 4.

Furthermore, with a flush toilet 2 equipped with a flush water tank device 1 according to this embodiment, the flow of flush water within the entire water storage tank body 22 can be improved, and it is possible to achieve both miniaturization of the small tank 62 and the entire water storage tank body 22, as well as improved supply performance of flush water supplied from the water storage tank body 22 to the toilet body 4 and improved toilet flushing performance.

1 Flush water tank device 2 Flush toilet 4 Toilet body 6 Bowl section 8 Rim section 10 Shelf section 12 Trap drain channel 12a Trap drain channel inlet 12b Trap drain channel ascent pipe 12c Trap drain channel downcomer pipe 14 Drain outlet 16 Toilet body water conduit 16a First water conduit 16b Second water conduit 18 First rim water outlet 20 Second rim water outlet 22 Water storage tank body 22a Base surface within water storage tank body 22b Lowest bottom surface within jet nozzle housing section of water storage tank body 24 Water supply pipe 26 Constant flow valve 28 Water supply valve device 30 Main valve (water supply valve)
30a: main valve body; 30b: main valve seat; 30c: pressure chamber; 32: operating device (operating portion)
32a Operating lever (operating part)
32b Drive rotation shaft (operation unit)
34 Poppet valve 34a Poppet hole 36 Float 38 Float side pilot valve 38a Float side pilot hole 40 Vacuum breaker valve 42 Jet pump unit 44 Water supply pipe 46 Jet nozzle 48 Flow path switching valve 50 Throat pipe 50a Suction port 50b Discharge port 50c Throat pipe descending pipe 52 Toilet flush flow path 54 Tank water storage flow path 56 Overflow pipe 56a Overflow port 58 Make-up water pipe 60 Large/small flush switching device 62 Small tank for switching between large and small flushes 64 Large/small flush switching valve device (large/small flush switching valve)
66 Small tank partition wall 66a Front partition wall 68 Small tank main body 68a Bottom surface of small tank main body 68b Support portion 68c Hinge protrusion (hinge portion)
68d Small communication hole 70 Projection 70a Right side partition wall of the projection (first side wall surface)
70b Left partition wall of protrusion (second side wall surface)
70c: lowest bottom surface of protrusion; 72: switching opening; 74: switching valve body (valve body of large/small flush switching valve);
74a Supported portion 74b Hinge hole (hinge portion)
74c Oscillating shaft 74d Weight 76 Oscillating member 78 Ball chain 80 Lifting lever A Primary flow path of water supply pipe B Secondary flow path of water supply pipe B0 Area rear of the longitudinal central axis of the water storage tank body C1 Longitudinal central axis that bisects the internal area of the water storage tank body into a front area and a rear area C2 Short-side central axis that bisects the internal area of the water storage tank body into a left area and a right area C3 Central axis that passes through the center of the opening cross section of the switching opening and extends in the left and right longitudinal directions of the water storage tank body C4 Longitudinal central axis of the throat pipe in plan view C5 Hinge axis DWL1 Minimum water level in the water storage tank body when each of the large and small flushes is completed DWL2 Minimum water level in the small tank when the small flush is completed F0 Area front of the longitudinal central axis of the water storage tank body H Jet nozzle accommodating section L0 Area on the left side of the central axis of the short side of the water storage tank body L1 Maximum width dimension in the left-right direction of the flow straightening area inside the small tank O1 Centre of the drain outlet of the water storage tank body, centre of the discharge outlet of the throat pipe O2 Centre of the opening cross section of the switching opening R0 Area on the right side of the central axis of the water storage tank body R1 Flow straightening area on the water storage tank body side R2 Flow straightening area inside the small tank S1 External area of the small tank S2 Internal area of the small tank T Exterior tank W Cleaning water W1 Maximum width dimension in the front-to-back short side direction of the protrusion of the small tank, maximum width dimension in the front-to-back direction of the flow straightening area inside the small tank W2 Maximum width dimensions when the internal area of the water storage tank body is divided in half in the short side direction WL0 Stopped water level, maximum water level WL1 Water level of the water storage tank body (external area of the small tank) WL2 Water level of the internal area of the small tank ΔP Water pressure difference ΔWL Water level difference α Primary side pressure

Claims (10)

A flush water tank device that supplies flush water to a toilet body of a flush toilet by jet pump action,
a water storage tank body capable of storing flush water for flushing the toilet body;
a water supply valve device including a water supply valve that enables the supply and stop of flush water supplied from a water supply source into the water storage tank body;
an operating unit that enables an operation to open the water supply valve of the water supply valve device when starting a toilet flush and also enables an operation to switch between setting a large amount or a small amount of flush water to be supplied to the toilet body;
a jet pump unit at least partially disposed submerged within the water storage tank body, the jet pump unit comprising: a throat pipe forming a drainage passage of the water storage tank body, the upstream end of which forms a suction port and the downstream end of which forms a discharge port connected to an inlet of the water conduit of the toilet body; and a jet nozzle for spraying flushing water toward the suction port of the throat pipe to induce a jet pump action;
a small tank for switching between large and small flushes that is provided within the water storage tank body and forms a small space in which less flush water is stored than the flush water stored in the entire water storage tank body, the small tank for switching between large and small flushes comprising a partition wall that extends vertically within the water storage tank body and separates an internal area and an external area of the small tank, and a switching opening that is formed to penetrate this partition wall;
a large/small flush switching valve that is provided so as to be opened and closed relative to the switching opening of the small tank by operation of the operating portion, and that switches between large and small amounts of flush water supplied to the toilet body through the jet pump unit,
The small tank includes a small tank main body portion provided within the water storage tank body so as to extend from one of the left and right sides to the other side in the longitudinal direction, and a protruding portion protruding downward from a lower end of the other side of the small tank main body portion to a bottom surface of the water storage tank body,
The overall shape of the small tank, which extends from one of the left and right sides of the small tank main body portion to the other side in the longitudinal direction and then protrudes downward by the protruding portion, is generally L-shaped in a front view,
A flush water tank apparatus characterized in that the switching opening is provided in the protruding portion. The water tank body has a longitudinal center axis that divides the interior area into a front area and a rear area, and a lateral center axis that divides the interior area into a left and right area,
The flush water tank device of claim 1, wherein the protrusion is arranged in an area within the water storage tank body on the other side of the short side of the short side of the central axis where the suction port is located, relative to an area on the left or right side of the short side of the central axis where the suction port is located, and is arranged in an area on the other side of the long side of the central axis where the center of the discharge port is not located, relative to an area on the front or rear side of the long side of the central axis where the center of the discharge port of the throat pipe is located. The flush water tank device according to claim 1 or 2, wherein the protrusion is formed so as to protrude from the lower end of the small tank body to a bottom surface inside the water storage tank body that is located below this lower end. The water storage tank body includes a bottom surface on which the lowest bottom surface of the protruding portion of the small tank is placed, and a jet nozzle accommodating portion formed in an area on one of the left and right sides of the bottom surface so as to protrude downward and capable of accommodating the jet nozzle,
4. A flush water tank apparatus according to claim 3, wherein the projection of the small tank is formed so as to project downward from the lower end of the small tank main body to the bottom surface within the water storage tank main body. the jet pump unit further includes a flow path switching valve provided in the jet nozzle housing portion and capable of switching a flow path of the cleaning water jetted from the jet nozzle,
A cleaning water tank device as described in claim 4, wherein this flow path switching valve is capable of switching the flow path of the cleaning water sprayed from the jet nozzle to either a drainage path that flows into the suction port of the throat pipe, or a water supply path that supplies water to the inside of the storage tank body other than the suction port, depending on the water level in the storage tank body. Furthermore, the toilet has an overflow pipe that, when the water level in the water storage tank body rises above the stop water level at which water is stopped by the water supply valve device, causes flush water that has risen above this stop water level to overflow into the water passage of the toilet body, and a make-up water passage that makes it possible to supply a portion of the flush water sprayed from the jet nozzle into the overflow pipe as make-up water,
The upstream side of the supply water passage is connected to the inside of the jet nozzle housing portion,
A cleaning water tank device as described in claim 5, wherein the flow path switching valve, when switched to a water supply path that supplies water to the water storage tank body other than the suction port, enables a portion of the cleaning water sprayed from the jet nozzle to be replenished to the replenishment water path. The flush water tank device according to any one of claims 1 to 6, in which the switching opening is provided on one side of the protrusion in the left-right longitudinal direction. The flush water tank device according to any one of claims 1 to 7, wherein the maximum width dimension of the protrusion in the front-rear short-side direction is set to be smaller than the maximum width dimension of each of the two equal parts obtained by dividing the maximum horizontal dimension of the internal area of the water storage tank body in the short-side direction. The flush water tank device of claim 2, wherein the protrusion is arranged in a region on the other left or right side of the short center axis of the water storage tank body where the suction port is not provided, in comparison with a region on the left or right side of the short center axis of the water storage tank body where the suction port is provided, and is arranged in a region forward of the longitudinal center axis, thereby being spaced apart from the suction port. A flush toilet equipped with a flush water tank device according to any one of claims 1 to 9.

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