Drain valve device, flush water tank device, and flush toilet

Abstract

To provide a drain valve device, a washing water tank device, and a water closet capable of changing a lowering speed of a float in association with drop of a water level in a water storage cylinder by changing a washing water amount (so called, draining capacity) that washing water in the water storage cylinder flows out from an outflow hole into a washing water tank according to a selected a large or small washing mode.SOLUTION: A drain valve device 1 includes a valve element 36, a water storage cylinder 62, and a float 72, where during a time from when the valve element is opened to when the same is closed, either a large washing mode that washing water in a water storage tank 12 is supplied from a drain port 18 to a water closet 4 at a first washing water amount or the small washing mode that the washing water is supplied at a second washing water amount smaller than the first washing water amount can be selectively executed. A first total outflow amount Q1 of washing water in the water storage cylinder 62 when flowing out from the outflow hole 72 to the water storage tank in the large washing mode is larger than a second total outflow amount Q2 of the washing water in a water storage cylinder body 68 when flowing out from the outflow hole to the water storage tank in the small washing mode.SELECTED DRAWING: Figure 6B

Description

Technical Field

[0001] The present invention relates to a drain valve device, a washing water tank device, and a water-washed toilet, and particularly to a drain valve device provided in a washing water tank device for supplying washing water to a water-washed toilet, a washing water tank device provided with this drain valve device, and a water-washed toilet provided with this washing water tank device.

Background Art

[0002] Conventionally, as a drain valve device provided in a washing water tank for supplying washing water to a water-washed toilet, for example, as described in Patent Documents 1 and 2, it includes a drain valve for opening and closing the drain port of the washing water tank, and in the opening and closing operation of this drain valve, a device using the buoyancy of a float is known. First, in the conventional drain valve device described in Patent Document 1 mentioned above, a valve body for opening and closing a drain port provided at the bottom of the washing water tank, an operating shaft for opening and closing the valve body by moving up and down, a water storage cylinder for inserting this operating shaft in the vertical direction and storing a part of the washing water in the washing water tank, and a float disposed in this water storage cylinder and applying buoyancy to the operating shaft are provided. Also, in the conventional drain valve device described in Patent Document 1 mentioned above, since the float is disposed in the water storage cylinder, the opening time of the drain valve can be made constant without being affected by the flow of the washing water outside the water storage cylinder. However, in each of the large and small washings, the amounts of washing water discharged from the drain port of the washing water tank are different from each other.

[0003] Next, the conventional drain valve device described in Patent Document 2 mentioned above is a so-called ball tap type drain valve device provided with two floats, a float for large washing and a float for small washing. In this drain valve device, by setting the opening time of the drain valve during large washing to be longer than the opening time of the drain valve during small washing, the amount of washing water during large washing can be set to be larger than the amount of washing water during small washing.

Prior Art Documents

[0004] [Patent Document 1] Japanese Patent Publication No. 2014-185491 [Patent Document 2] Japanese Patent Publication No. 2019-157601 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, in the conventional drain valve device described in Patent Document 1 mentioned above, the opening time of the drain valve is kept constant during both large and small wash cycles, while a difference is created in the amount of wash water discharged from the drain port of the wash water tank. As a result, especially during small-scale flushing, the flow rate per unit time (hereinafter referred to as "instantaneous flow rate") [L / min] of the flushing water discharged from the drain outlet immediately after the drain valve opens reaches almost the same maximum value (so-called "drainage peak") as during large-scale flushing. However, while the drain valve remains open thereafter, the instantaneous flow rate [L / min] decreases significantly compared to large-scale flushing. Therefore, maintaining the instantaneous flow rate [L / min] as high as possible has been a challenge required to ensure good flushing performance. Furthermore, in the conventional drain valve device described in Patent Document 2 mentioned above, by using two floats, one for large-scale washing and one for small-scale washing, the opening time of the drain valve is changed for each of the large-scale and small-scale washing processes. As a result, the instantaneous flow rate [L / min] of the washing water discharged from the drain outlet during small-scale washing can be maintained at a relatively high level. However, the higher the instantaneous flow rate [L / min] of the cleaning water discharged from the drain outlet is maintained, the louder the closing noise generated when the drain valve closes the drain outlet becomes. This presents a problem in that the design of the two floats, one for large flushing and one for small flushing, needs to be carefully considered in terms of their respective sizes. Therefore, the inventors focused on changing the amount of cleaning water (so-called "water drainage amount") that flows from the water reservoir into the cleaning water tank through the outlet hole, depending on the selected large or small cleaning mode, in order to maintain a relatively high instantaneous flow rate [L / min] of cleaning water discharged from the drain outlet during small cleaning and to reduce the closing noise generated when the drain valve closes the drain outlet. This allowed us to change the descent speed of the float in the water tank as the water level drops according to the cleaning mode, and we found various means to change the float descent time and the valve opening time.

[0006] In other words, the present invention has been made to solve the problems of the prior art and the conventional issues described above, and aims to provide a drain valve device, a flush water tank device, and a flush toilet that can change the rate at which the float descends as the water level in the water reservoir decreases, by changing the amount of flush water (so-called "water drainage amount") that flows out of the drain hole into the flush water tank from the water reservoir according to the selected large flush mode or small flush mode, thereby maintaining a relatively high instantaneous flow rate [L / min] of flush water discharged from the drain outlet during small flushing, and reducing the closing noise generated when the drain valve closes the drain outlet. [Means for solving the problem]

[0007] To solve the above-mentioned problems, the present invention provides a drain valve device installed in a flush water tank that supplies flush water to a flush toilet, comprising: a valve body that opens and closes a drain port provided at the bottom of the flush water tank; an operating shaft provided at the lower end of the valve body that opens and closes the valve body by moving up and down; a water storage cylinder through which the operating shaft is inserted in the vertical direction and which stores a portion of the flush water in the flush water tank, the water storage cylinder having an outlet hole formed therein for the flush water to flow out to the outside; and a float disposed inside the water storage cylinder that applies buoyancy obtained from the flush water in the water storage cylinder to the operating shaft, wherein the operating shaft and the valve body are configured such that the float is lowered when the water level in the water storage cylinder is low As it descends, the valve body is configured to descend in conjunction with the float, closing the drain port. Between the time the valve body is open and closed, either a large flush mode, in which the flushing water in the water storage tank is supplied to the toilet bowl from the drain port at a first flushing volume, or a small flush mode, in which the flushing water is supplied at a second flushing volume less than the first flushing volume, can be selectively performed. The large flush mode is characterized in that the first total outflow volume of flushing water from the water storage cylinder to the flushing water tank from the outflow hole is greater than the second total outflow volume of flushing water from the water storage cylinder to the flushing water tank from the outflow hole in the small flush mode. In the present invention configured as described above, when starting the flushing of a toilet, first, one of the flushing modes, either the large flush mode or the small flush mode, is selected, and then the operating shaft of the drain valve device is raised, causing the valve body to rise (open), and flushing water from the flushing water tank is supplied to the toilet from the drain outlet. Then, depending on the selected large or small flush mode, the water level in the reservoir decreases, and as the water level drops, the float in the reservoir descends. This causes the operating shaft of the drain valve device to descend, which in turn causes the valve body to descend (close), stopping the supply of flushing water from the flushing water tank to the toilet bowl, and ending the flushing of the toilet bowl. In this case, the first total outflow amount of cleaning water from the reservoir to the cleaning water tank through the outflow hole in the large cleaning mode is greater than the second total outflow amount of cleaning water from the reservoir to the cleaning water tank through the outflow hole in the small cleaning mode. Therefore, the descent speed of the float in the small cleaning mode can be made greater than the descent speed of the float in the large cleaning mode. This allows the float descent time and valve opening time in the small flush mode to be shorter than those in the large flush mode. As a result, depending on the selected large or small flushing mode, the amount of flushing water (the so-called "water drainage amount") that flows from the water reservoir into the flushing water tank through the outlet hole can be changed, thereby altering the rate at which the float descends as the water level in the reservoir decreases. Therefore, the flow rate of the cleaning water per unit time (hereinafter referred to as "instantaneous flow rate") [L / min], which affects cleaning performance, can be maintained at a relatively high level even in the small cleaning mode, which uses less cleaning water than the large cleaning mode. In addition, the closing noise generated when the valve body closes the drain outlet can also be reduced.

[0008] In the present invention, preferably, the water storage cylinder comprises a water storage cylinder body having the outlet hole and a small tank connected to the water storage cylinder body so as to be able to communicate with it, the small tank comprising a communication opening that communicates with the water storage cylinder body and a partition that opens and closes the communication opening, the partition which opens the communication opening in the large washing mode to connect the water storage cylinder body and the small tank, and which closes the communication opening in the small washing mode to separate the water storage cylinder body and the small tank. In the present invention configured in this way, the small tank, which is connected to the water storage cylinder body so as to be able to communicate with it, is equipped with a communication opening that communicates with the water storage cylinder body and a partition that opens and closes the communication opening. The partition opens the communication opening in the large-scale washing mode, thereby enabling communication between the water storage cylinder body and the small tank. On the other hand, the partition in the small tank can separate the main water reservoir from the small tank by closing the communication opening in the small flushing mode. As a result, in the large-scale flushing mode, the first total outflow rate of flushing water from the reservoir to the flushing water tank through the outflow hole can be made larger than the second total outflow rate of flushing water from the reservoir to the flushing water tank through the outflow hole in the small-scale flushing mode. Therefore, the descent speed of the float in the small-scale flushing mode can be made larger than the descent speed of the float in the large-scale flushing mode. This allows the float descent time and valve opening time in the small flush mode to be shorter than those in the large flush mode. As a result, depending on the selected large or small flushing mode, the amount of flushing water (the so-called "water drainage amount") that flows from the water reservoir into the flushing water tank through the outlet hole can be changed, thereby altering the rate at which the float descends as the water level in the reservoir decreases. Therefore, the instantaneous flow rate [L / min] of the cleaning water, which affects cleaning performance, can be maintained at a relatively high level even in the small cleaning mode, which uses less cleaning water than the large cleaning mode. In addition, the closing noise generated when the valve body closes the drain outlet can also be reduced.

[0009] In the present invention, preferably, the partition portion is provided so as to be rotatable with respect to the communication opening, and rotates in a direction that opens the communication opening in the large cleaning mode, and rotates in a direction that closes the communication opening in the small cleaning mode. In the present invention configured as described above, if the partition is not rotatable relative to the communication opening, but rather slidable relative to the communication opening, then when the communication opening is closed by the partition, the sealing portion in contact with the partition and the communication opening is at risk of being damaged due to wear and tear caused by repeated opening and closing and sliding of the partition relative to the communication opening. However, according to the present invention, the partition is rotatably provided with respect to the communication opening, and can rotate in a direction that opens the communication opening in the large washing mode and in a direction that closes the communication opening in the small washing mode. This design, compared to a configuration where the partition slides open and closed relative to the communication opening, reduces the number of parts while avoiding the risk of the partition constantly contacting the communication opening regardless of the cleaning mode. As a result, it reduces the risk of damage due to wear or other factors to the part of the small tank's communication opening that the partition contacts when closed (the sealing portion).

[0010] In the present invention, preferably, the communication opening is provided with a locking portion on its rim that rotatably supports the partition portion, and in the small washing mode, the locking portion restricts the rotation of the partition portion by rotating in a direction that closes the communication opening and contacting the locking portion. In the present invention configured as described above, the communication opening of the small tank is provided with a locking portion at its rim that rotatably supports the partition portion. Therefore, when the partition portion rotates in a direction that closes the communication opening and comes into contact with the locking portion during the small flushing mode, the locking portion can reliably restrict the rotation of the partition portion. Furthermore, in the small flushing mode, when the partition is in contact with the locking portion, the partition and the rim of the communication opening can be reliably sealed by the locking portion, thereby improving the watertightness between the water storage cylinder body and the small tank. Therefore, in the small flushing mode, it is possible to reliably prevent the flushing water in the small tank from flowing into the water storage cylinder body through the communication opening.

[0011] In the present invention, preferably, the partition portion further comprises a water weight portion for storing cleaning water, and the small tank further comprises an auxiliary outlet hole formed on its bottom surface for draining the cleaning water from the small tank. When the partition portion is in contact with the locking portion, the water weight portion is capable of storing cleaning water and the auxiliary outlet hole of the small tank is open. When the cleaning water from the small tank drains out through the auxiliary outlet hole, the partition portion rotates in a direction away from the locking portion and drains the cleaning water from the water weight portion. In the present invention configured in this way, the partition is equipped with a water weight for storing cleaning water, and the small tank is equipped with an auxiliary outlet hole formed on its bottom surface for draining the cleaning water from the small tank. Therefore, when the partition is in contact with the locking portion, the water weight can store cleaning water, and the cleaning water from the small tank can be drained out through the auxiliary outlet hole. Furthermore, as the cleaning water in the small tank flows out through the auxiliary outlet hole, the partition rotates in a direction that separates it from the locking part, allowing the cleaning water in the water weight section to flow out. Therefore, the series of rotational movements from when the partition closes the communication opening of the small tank to when it opens can be reliably and smoothly performed by utilizing the change in the water level in the small tank and the change in the amount of washing water stored in the water weight.

[0012] In the present invention, preferably, the partition portion is in an initial position without contacting the locking portion, leaving the communication opening open and no cleaning water stored in the water weight portion. During the standby period when no cleaning mode is being performed and during the period when the large cleaning mode is being performed, the partition portion is maintained in the initial position, thereby closing the auxiliary outlet hole of the small tank and allowing cleaning water to be stored in the small tank. On the other hand, during the period when the small cleaning mode is being performed, the partition portion rotates from the initial position and contacts the locking portion, maintaining the state of closing the communication opening. After the cleaning water in the small tank flows out through the auxiliary outlet hole, the partition portion is configured to rotate toward the initial position, allowing the cleaning water in the water weight portion to flow out before returning to the initial position. In the present invention configured as described above, in the initial position, the partition portion does not contact the locking portion, the communication opening is open, and no cleaning water is stored in the water hammer portion. During the standby period when no cleaning mode is being executed and during the period when the large cleaning mode is being executed, the partition portion is maintained in the initial position, whereby the auxiliary outflow hole of the small tank is closed, and cleaning water can be stored in the small tank. On the other hand, during the period when the small cleaning mode is being executed, after the partition portion rotates from the initial position and contacts the locking portion to maintain the state of closing the communication opening, when the cleaning water in the small tank flows out from the auxiliary outflow hole, the partition portion can return to the initial position after discharging the cleaning water in the water hammer portion while rotating towards the initial position. As a result, according to the selected large cleaning mode or small cleaning mode, by efficiently changing the amount of cleaning water (so-called "draining amount") that flows out from the outflow hole into the cleaning water tank in the water storage cylinder, the descending speed of the float accompanying the lowering of the water level in the water storage cylinder can be efficiently changed.

[0013] In the present invention, preferably, the upper edge of the water storage cylinder main body and the upper edge of the small tank are flush with each other. When the partition portion closes the communication opening, the upper end of the partition portion protrudes above the upper edge of the communication opening or the upper edge of the small tank. In the present invention configured as described above, since the upper edge of the water storage cylinder main body and the upper edge of the small tank are flush with each other, and when the partition portion closes the communication opening of the small tank, the upper end of the partition portion protrudes above the upper edge of the communication opening or the upper edge of the small tank, the inflow from the small tank into the water storage cylinder main body can be reliably suppressed.

[0014] Further, the present invention is a cleaning water tank device provided with the above-described drain valve device. In the present invention configured as described above, according to the selected large cleaning mode or small cleaning mode, by changing the amount of cleaning water (so-called "water drainage amount") in the water storage cylinder that flows out from the outflow hole into the cleaning water tank, the descending speed of the float accompanying the water level drop in the water storage cylinder can be changed, the instantaneous flow rate [L / min] of the cleaning water discharged from the drain port during small cleaning can be maintained relatively high, and a cleaning water tank device provided with a drain valve device capable of reducing the closing sound generated when the valve body closes the drain port can be provided.

[0015] Furthermore, the present invention is a water-washed toilet provided with the above-described cleaning water tank device. In the present invention configured as described above, according to the selected large cleaning mode or small cleaning mode, by changing the amount of cleaning water (so-called "water drainage amount") in the water storage cylinder that flows out from the outflow hole into the cleaning water tank, the descending speed of the float accompanying the water level drop in the water storage cylinder can be changed, the instantaneous flow rate [L / min] of the cleaning water discharged from the drain port during small cleaning can be maintained relatively high, and a water-washed toilet provided with a cleaning water tank device having a drain valve device capable of reducing the closing sound generated when the valve body closes the drain port can be provided.

Effects of the Invention

[0016] According to the drain valve device, cleaning water tank device, and water-washed toilet of the present invention, according to the selected large cleaning mode or small cleaning mode, by changing the amount of cleaning water (so-called "water drainage amount") in the water storage cylinder that flows out from the outflow hole into the cleaning water tank, the descending speed of the float accompanying the water level drop in the water storage cylinder can be changed, the instantaneous flow rate [L / min] of the cleaning water discharged from the drain port during small cleaning can be maintained relatively high, and the closing sound generated when the drain valve closes the drain port can be reduced.

Brief Description of the Drawings

[0017] [Figure 1]This is a perspective view from diagonally above of a flushing water tank device and a flush toilet to which a drain valve device according to one embodiment of the present invention is applied. [Figure 2] This is a front cross-sectional view of a washing water tank device equipped with a drain valve device according to one embodiment of the present invention. [Figure 3] This is a perspective view of a drain valve device according to one embodiment of the present invention, seen from diagonally above. [Figure 4] This is a top view of a drain valve device according to one embodiment of the present invention. [Figure 5] This is a cross-sectional view along the VV line in Figure 4. [Figure 6A] This diagram shows the configuration of a drain valve device according to one embodiment of the present invention, as well as a schematic diagram illustrating the series of operations from the standby state to the opening and closing of the valve in the large-scale flushing mode. [Figure 6B] This diagram shows the configuration of a drain valve device according to one embodiment of the present invention, as well as a schematic diagram illustrating the series of operations from the standby state to the opening and closing of the valve in the small flush mode. [Modes for carrying out the invention]

[0018] Hereinafter, with reference to the attached drawings, several embodiments relating to the drain valve device of the present invention, the flush water tank device equipped with this drain valve device, and the flush toilet equipped with this flush water tank device will be described. First, with reference to Figures 1 to 3B, we will describe a drain valve device 1 according to one embodiment of the present invention, a flush water tank device 2 equipped with this drain valve device 1, and a flush toilet 4 equipped with this flush water tank device 2. Figure 1 is a perspective view from diagonally above of a flushing water tank device 2 and a flush toilet 4 to which a drain valve device 1 according to one embodiment of the present invention is applied. Figure 2 is a front cross-sectional view of the flushing water tank device 2 equipped with the drain valve device 1 according to one embodiment of the present invention.

[0019] As shown in Figures 1 and 2, a flush toilet 4 equipped with a flush water tank device 2 to which a drain valve device 1 according to one embodiment of the present invention is applied includes a ceramic toilet body 8 that forms a bowl portion 6. A flushing water tank device 2, which will be described in detail later, is provided on the rear side of the upper surface of the toilet bowl body 8. When the flushing water stored in this flushing water tank device 2 is supplied to the toilet bowl body 8 of the flush toilet 4 by the operation of the drain valve device 1 of this embodiment, the inside of the bowl 6 is flushed. Here, the form of the flush toilet 4 equipped with a flush water tank device 2 to which the drain valve device 1 of this embodiment is applied may be, for example, a so-called "siphon-type flush toilet" which uses a siphon action to suck up the waste in the bowl 6 and discharge it to the outside all at once from a downstream drain trap (not shown), or a so-called "wash-down type flush toilet" which uses the flowing water action caused by the difference in water level in the bowl 6 to wash away the waste.

[0020] Next, with reference to Figure 2, the schematic configuration of the washing water tank device 2 to which the drain valve device 1 of this embodiment is applied will be described. As shown in Figure 2, the flushing water tank device 2 comprises a ceramic outer tank 10, a water storage tank 12 located inside the outer tank 10 which stores flushing water for flushing the toilet bowl, and a lid 14 placed on top of the outer tank 10. First, the water storage tank 12 is attached to the outer tank 10 via an insulating material 16 that surrounds its outer periphery. Furthermore, drain ports 18 are provided at the bottom of both the water storage tank 12 and the outer tank 10, which communicate with the water conduit 8a of the toilet bowl body 8. These drain ports 18 can be opened and closed by the drain valve device 1 of this embodiment, which will be described in detail later. In this embodiment, the lid 14 of the washing water tank device 2 will be described in a form in which there is no hand-washing bowl (hand-washing basin) or hand-washing faucet, etc., on its upper surface. However, this embodiment is also applicable to forms in which such hand-washing means are provided.

[0021] Next, as shown in Figure 2, the cleaning water tank device 2 is equipped with a water supply device 20 that supplies cleaning water into the water storage tank 12. This water supply device 20 includes a water supply pipe 22, a valve unit 24 including a water supply valve (not shown), a water supply float 26, and a water discharge pipe 28, etc. First, the water supply pipe 22 connects the valve unit 24 to an external water source (not shown), such as an external water pipe, and is capable of supplying cleaning water from the external water source (not shown) to the valve unit 24. Next, the water supply float 26 is connected to the valve unit 24 via a lever 30, and moves up and down according to the water level in the water storage tank 12, thereby opening and closing the water supply valve (not shown) of the valve unit 24. Furthermore, the discharge pipe 28 is connected to the downstream side of the valve unit 24, and by opening and closing the water supply valve (not shown), the valve unit 24 can discharge and stop the water supply (supply and stop) of cleaning water into the water storage tank 12.

[0022] Next, as shown in Figure 2, the cleaning water tank device 2 is equipped with an operating device 32 for opening and closing the drain valve device 1. The operating device 32 includes an operating lever 34 that is manually rotated by the user, an operating part (lifting operating part 38) that lifts the valve body 36 of the drain valve device 1, and a plurality of rotating shafts (outer rotating shaft 40, inner rotating shaft 42) that connect the operating lever 34 and the lifting operating part 38.

[0023] First, the operating lever 34 is located on one of the outer sides of the outer tank 10 (the right side when viewing the outer tank 10 of the washing water tank device 2 shown in Figure 2 from the front), and can be rotated manually by the user around the rotational axis A1 which extends in the left-right direction. Next, the outer rotating shaft 40 is located inside the outer tank 10 and extends in the left-right direction, with one end (the side with the operating lever 34) connected to the operating lever 34. Furthermore, the other end (inner end) of the outer rotating shaft 40 is connected to one end (outer end) of the inner rotating shaft 42, which is located inside it.

[0024] Next, the upper end of the lifting mechanism 38 is fixed to the upper end and central side of the water storage tank 12. The lifting mechanism 38 comprises a rotating main shaft portion 44 connected to the other end (inner end) of the inner rotating shaft 42, and a cylindrical rotating portion 46 provided on the outer circumference of the rotating main shaft portion 44. The cylindrical rotating portion 46 is designed to rotate integrally with the rotating main shaft portion 44 around the rotational axis A2 when the rotating main shaft portion 44 rotates around the rotational axis A2. Furthermore, the cylindrical rotating part 46 includes a first oscillating lever 48 that is involved in lifting the valve body 36 of the drain valve device 1 when opening the valve body 36 in order to start flushing the toilet bowl, and a second oscillating lever 50 that is involved in switching the toilet bowl flushing mode to either the full flush mode or the small flush mode. Furthermore, the upper side of the first ball chain 52 is connected to the first swing lever 48, and the lower side of this first ball chain 52 is connected to the upper end of the operating shaft 54 ​​that operates (directly moves) the valve body 36 of the drain valve device 1, which will be described in detail later. On the other hand, the second swing lever 50 is connected to the upper side of the second ball chain 56, and the lower side of this second ball chain 56 is connected to a part of the partition section (switching valve 58 for switching between large and small flushes) for switching between large and small flushes in the drain valve device 1, which will be described in detail later.

[0025] For example, when starting toilet flushing in full flush mode, rotating the operating lever 34 shown in Figure 2 by a predetermined angle (for example, 90 degrees) to one side (towards the front in Figure 2) around the rotational axis A1 causes the outer rotation shaft 40 and inner rotation shaft 42 connected to the operating lever 34 to rotate to one side, and the rotating main shaft 44 of the lifting operation unit 38 to rotate to one side around the rotational axis A2. As a result, the cylindrical rotating part 46 of the lifting mechanism 38 also rotates integrally with the rotating main shaft 44 around the rotational axis A2 to one side (towards the front in Figure 2), causing the first swing lever 48 to swing (rotate) to one side (towards the front in Figure 2) to lift the first ball chain 52, and the second swing lever 50 to swing (rotate) to one side (towards the front in Figure 2) to lift the second ball chain 56. On the other hand, when starting toilet flushing in light flush mode, rotating the operating lever 34 shown in Figure 2 by a predetermined angle (for example, 90 degrees) around the rotational axis A1 to the other side (towards the back in Figure 2) causes the outer rotation shaft 40 and inner rotation shaft 42 connected to the operating lever 34 to rotate to the other side, and the rotating main shaft 44 of the lifting operation unit 38 to rotate to the other side around the rotational axis A2. As a result, the cylindrical rotating part 46 of the lifting mechanism 38 also rotates integrally with the rotating main shaft part 44 around the rotational axis A2 to the other side (the far side in Figure 2), causing the first swing lever 48 to swing (rotate) to the other side (the far side in Figure 2) to lift the first ball chain 52, while the second swing lever 50 does not swing, and the second ball chain 56 is not lifted.

[0026] In this embodiment, the operating device 32 for operating the drain valve device 1 is described as a configuration in which the user manually operates the operating lever 34. However, the embodiment is not limited to this configuration and can be applied to other configurations as well. For example, in another form of the operating device, the controller may electrically control the operation of the drive unit (motor, etc.) of the lifting mechanism based on signals input by the user via operation buttons, etc., thereby automatically performing operations such as lifting the valve body 36 of the drain valve device 1 using the first swing lever 48 and switching between large and small flushing modes using the second swing lever 50. Furthermore, the ball chains 52 and 56 of the drain valve device 1 in this practical configuration may be made of linear wire members.

[0027] Next, the details of the drain valve device 1 of this embodiment will be described with reference to Figures 2 to 6B. First, Figure 3 is a perspective view of a drain valve device according to one embodiment of the present invention, viewed from diagonally above. Next, Figure 4 is a top view of a drain valve device according to one embodiment of the present invention. Furthermore, Figure 5 is a cross-sectional view along the VV line in Figure 4. Furthermore, Figure 6A is a schematic diagram showing the configuration of a drain valve device according to one embodiment of the present invention, as well as a series of operations from the standby state to the opening and closing of the valve in the large flush mode. Furthermore, Figure 6B is a schematic diagram showing the configuration of a drain valve device according to one embodiment of the present invention, as well as a series of operations from the standby state to the closing of the valve in the small flush mode. Here, in the large flush mode and small flush mode shown in Figures 6A and 6B, the state (I) to (VI) of the drain valve device 1 is defined as state (I) before the valve body 36 starts opening (standby state), and thereafter, the open state of the valve body 36 is defined as state (II) to (V) in chronological order, and the closed state of the valve body 36 is defined as state (VI).

[0028] First, as shown in Figure 2, the drain valve device 1 of this embodiment includes a drain outlet forming section 60 attached to the bottom surface of the water storage tank 12 to form a drain outlet 18, a water storage cylinder 62 provided above the drain outlet forming section 60, and an overflow pipe 64 attached to the drain outlet forming section 60 so as to communicate with the drain outlet 18. Next, as shown in Figure 2, the drain valve device 1 includes a valve seat 66 formed on the upper edge of the drain port 18, a valve body 36 that is fixed to the valve seat 66 and movable linearly upward, and an operating shaft 54 ​​provided at the lower end of the valve body 36 that opens and closes the valve body 36 by moving linearly (up and down) in the vertical direction. This operating shaft 54 ​​is provided so as to be inserted vertically into the water storage cylinder 62. Furthermore, the water storage cylinder 62 comprises a water storage cylinder body 68 and a small tank 70 that is connected to the water storage cylinder body 68 so as to be able to communicate with it. The water storage cylinder body 68 and the small tank 70 are each designed to store a portion of the cleaning water in the water storage tank 12. Furthermore, the side wall portion 68a of the water storage cylinder body 68 is provided with an outlet hole 72 that allows the cleaning water inside the water storage cylinder body 68 to flow out to the outside (into the water storage tank 12). This outlet hole 72 is always open, and the inside of the water storage cylinder body 68 and the inside of the water storage tank 12 outside are always in communication. Furthermore, a float 74 is positioned inside the water reservoir body 68. This float 74 is concentrically located on the outer circumference of the operating shaft 54 ​​and moves up and down in conjunction with the water level inside the water reservoir body 68, allowing the buoyancy obtained from the washing water inside the water reservoir body 68 to act on the operating shaft 54.

[0029] Next, as shown in Figures 2 to 6B, the connection portion of the small tank 70 connected to the side wall portion 68a of the water storage cylinder body 68 is provided with a communication opening 76 that can communicate with the water storage cylinder body 68. Furthermore, the communication opening 76 is provided with a partition (switching valve 58) that can be opened and closed for switching between large and small flushing. As shown in Figures 2 to 6A, when the toilet bowl is flushed in full flush mode, the second ball chain 56 is not pulled up by the second swing lever 50 but becomes loose, causing it to rotate in the direction C1 that opens the communication opening 76, thus allowing the communication opening 76 to be opened. As a result, in full flush mode, the water reservoir body 68 and the small tank 70 are connected to each other through the open communication opening 76. On the other hand, as shown in Figures 2 to 5 and 6B, when the toilet bowl is flushed in small flush mode, the second ball chain 56 is pulled up by the second swing lever 50, causing it to rotate in direction C2, which closes the communication opening 76, thus allowing the communication opening 76 to be closed. As a result, in the small flushing mode, the water reservoir body 68 and the small tank 70 are isolated from each other by a switching valve 58 that closes the communication opening 76.

[0030] Next, as shown in Figures 3 to 5, locking portions 78 are provided on both the left and right sides and the lower end of the rim of the communication opening 76 to rotatably support the switching valve 58. In the small flushing mode, the locking portion 78 restricts the rotation of the switching valve 58 by rotating in the direction C2 that closes the communication opening 76 and coming into contact with the locking portion 78.

[0031] Next, as shown in Figures 3 to 5, the switching valve 58 includes a valve body 80 and a water weight 82. First, when the switching valve 58 is closing the communication opening 76, the entire valve body 80 of the switching valve 58 is in an upright position with its vertically extended shape due to the lifting force from the second swing lever 50 and the second ball chain 56, and the water pressure of the cleaning water in the small tank 70, with the left, right, and lower peripheral edges of the valve body 80 in contact with the locking portion 78. Furthermore, multiple (two) water weights 82 of the switching valve 58 are provided on the upper side of the valve body 80 in the upright position and on the side of the small tank 70. Each of these water weights 82 is designed to store cleaning water when the valve body 80 is in the upright position.

[0032] Furthermore, as shown in Figure 4, the bottom surface of the small tank 70 is provided with a pair of auxiliary outlet holes 84 on the left and right sides to allow the washing water inside the small tank 70 to flow out. Furthermore, in the upright position where the valve body 80 is in contact with the locking portion 78, the water weight portion 82 can store cleaning water, and at this time, each of the auxiliary outlet holes 84 of the small tank 70 is open by the valve body 80. Furthermore, when the cleaning water in the small tank 70 flows out through each auxiliary outlet hole 84, the water pressure in the small tank 70 that is pressing the valve body 80 in the closing direction decreases, causing the valve body 80 to rotate in a direction away from the locking portion 78 (in the opening direction). As a result, the valve body 80 and the water weight 82 can easily rotate from an upright position to a prone position due to the weight of the water weight 82. As the water weight portion 82 tilts, the cleaning water inside the water weight portion 82 is discharged, and the valve body portion 80 and the water weight portion 82 (see reference numerals 80 and 82, indicated by dashed lines in Figure 5) transition to an inverted position (horizontal position). Furthermore, when the valve body 80 and the water weight 82 are in a tilted (horizontal) position, each auxiliary outflow hole 84 is closed by the lower surface of the tilted water weight 82.

[0033] Incidentally, in the initial position P0 during the waiting period before the large / small flush mode is started (see state (I) in Figures 6A and 6B), the valve body 80 and water weight 82 of the switching valve 58 are in a reclined position (horizontal position). Furthermore, even during the period when the large-scale cleaning mode shown in states (II) to (VI) of Figure 6A is being executed, following the waiting period shown in state (I) of Figure 6A, the valve body 80 and water weight 82 of the switching valve 58 remain in their initial position P0, maintaining a tilted (horizontal) posture. Furthermore, when the valve body 80 and water weight 82 of the switching valve 58 are in the inverted position (horizontal position) at the initial position P0, the valve body 80 of the switching valve 58 does not come into contact with the locking portion 78, thereby opening the communication opening 76 and closing each of the auxiliary outlet holes 84. Furthermore, when the valve body 80 and the water weight 82 are in an inverted (horizontal) position, the open end 82a (see Figure 3) at the tip of the water weight 82 is directed horizontally, allowing the cleaning water in the small tank 70 to flow into the water weight 82 from the open end 82a, and enabling the cleaning water to be stored in the water weight 82. On the other hand, during the period when the small cleaning mode shown in states (II) to (VI) of Figure 6B is being executed, the valve body 80 and water weight 82 of the switching valve 58 rotate from the initial position P0 and come into contact with the locking portion 78, thereby maintaining the state in which the communication opening 76 is closed. Then, when the cleaning water in the small tank 70 flows out from each auxiliary outlet hole 84, the valve body 80 and water weight 82 rotate toward the initial position P0, allowing the cleaning water in the water weight 82 to flow out, and then return to the initial position P0 of the standby state (I).

[0034] Next, as shown in Figures 3 to 5, the upper edge 68b of the water storage cylinder body 68, the upper edge 70a of the small tank 70, and the upper end 78a of the locking portion 78 are flush with each other. Furthermore, as shown in Figure 3 and the Figure, when the switching valve 58 is closing the communication opening 76, the upper end 58a of the switching valve 58 (valve body 80 and water weight 82) protrudes above the upper edge of the communication opening 76 and the upper edge 70a of the small tank 70. With the configuration of the drain valve device 1 of these embodiments, in the large flushing mode from state (III) to (VI) in Figure 6A, the first total outflow amount (first water drainage amount) Q1 [L] of the flushing water from the water storage cylinder 62 flowing out from the outflow hole 72 into the water storage tank 12 is greater than the second total outflow amount (second water drainage amount) Q2 [L] of the flushing water from the water storage cylinder 62 flowing out from the outflow hole 72 into the water storage tank 12 in the small flushing mode from state (III) to (VI) in Figure 6B (Q1 > Q2).

[0035] Next, the operation of the drain valve device 1 according to one embodiment of the present invention will be explained with reference to Figures 2 to 6B. First, the large-scale flushing mode performed by the drain valve device 1 according to one embodiment of the present invention will be explained with reference to Figures 2 to 6A. As shown in Figures 2 and 6A, when starting the full-scale cleaning mode from the standby state (I), for example, if the user rotates the operating lever 34 shown in Figure 2 90 degrees towards them, only the first swinging lever 48 in the initial position (standby state) shown in Figure 2 will swing, and only the first ball chain 52 will be raised. As a result, the operating shaft 54 ​​and valve body 36 of the drain valve device 1 are pulled up and moved straight upward via the first ball chain 52, and the float 74 is also pulled up integrally via this operating shaft 54 ​​(see state (II) in Figure 6A). On the other hand, since the second ball chain 56 is not pulled up by the second swing lever 50, the switching valve 58 is in the initial position P0 and has rotated to open the communication opening 76 of the water storage cylinder 62, so that the water storage cylinder body 68 and the small tank 70 are in communication (see state (II) in Figure 6A). Subsequently, the water reservoir body 68 and the small tank 70 remain in constant communication until the main flushing mode is completed (see states (II) to (VI) in Figure 6B).

[0036] Furthermore, at this time, as shown in state (II) of Figure 6A, the float 74 and valve body 36 rise to their highest positions, the drain port 18 of the water storage tank 12 is opened by the raised valve body 36, and the drainage of cleaning water from inside the water storage tank 12 to the drain port 18 begins. Subsequently, as shown in states (III) to (V) of Figure 6A, when the water level W1 in the water storage tank 12 decreases and falls below the upper end of the water storage cylinder 62, the water pressure due to the water level W2 in the water storage cylinder 62 exceeds the water pressure due to the water level W1 in the water storage tank 12 outside it. As a result, the cleaning water in the water storage cylinder 62 flows out through the outlet hole 72 into the water storage tank 12 outside it. As shown in states (III) and (IV) of Figure 6A, the water level W2 inside the water storage cylinder 62 is higher than the water level W1 inside the water storage tank 12 outside it. However, since the cleaning water inside the water storage cylinder 62 continues to flow out through the outlet hole 72, the water level W2 inside the water storage cylinder 62 gradually decreases, and the float 74 also descends in conjunction with the decrease in water level W2.

[0037] Next, as shown in state (V) of Figure 6A, when the water level W1 in the water storage tank 12 outside the water storage cylinder 62 falls below the upper end of the outlet hole 72 of the water storage cylinder 62, the outside of the outlet hole 72 of the water storage cylinder 62 is opened to the atmosphere. As a result, the rate at which the cleaning water in the reservoir 62 flows out through the outlet hole 72 is increased, and the water level W2 in the reservoir 62 falls further, causing the float 74 to also descend, and the operating shaft 54 ​​and valve body 36 to descend together. Then, as shown in the state (VI) of Figure 6A, when the valve body 36 comes into contact with the valve seat 66, the drain port 18 is closed. As a result, the drainage of flushing water from the water storage tank 12 to the drain outlet 18 is stopped, and the supply of flushing water from the flushing water tank device 2 to the toilet bowl body 8 in full flush mode is terminated. At this time, the float 74, the operating shaft 54, and the valve body 36 are in a stopped state, but the lowest water level DWL1 in the water storage tank 12 (the so-called "dead water line," which is the drainage stop water level) is located below the lower end of the outflow hole 72 of the water storage cylinder 62. Therefore, the cleaning water in the water storage cylinder 62 continues to flow out through the outlet hole 72 to the water storage tank 12, causing only the water level W2 in the water storage cylinder 62 to gradually decrease, and the water pressure in the water storage cylinder 62 also decreases. Furthermore, after the completion of the main cleaning mode and during the standby state until the next cleaning mode starts, the switching valve 58 keeps the communication opening 76 open, maintaining communication between the water storage cylinder body 68 and the small tank 70.

[0038] Next, a small flushing mode performed by the drain valve device 1 according to one embodiment of the present invention will be described with reference to Figures 2 to 5 and Figure 6B. When starting the light cleaning mode from the standby state (I) shown in Figures 2 and 6B, for example, if the user rotates the operating lever 34 shown in Figure 2 90 degrees to the rear, the first swing lever 48 and the second swing lever 50, which are in the initial position (standby state) shown in Figure 2, will swing, and the first ball chain 52 and the second ball chain 56 will be pulled up. As a result, the operating shaft 54 ​​and valve body 36 of the drain valve device 1 are pulled up via the first ball chain 52 and move linearly upward, and the float 74 is also pulled up integrally via this operating shaft 54 ​​(see state (II) in Figure 6B). Furthermore, the switching valve 58 for switching between large and small flushes is raised via the second ball chain 56, and this switching valve 58 rotates from a state in which the communication opening 76 of the water reservoir 62 is open (initial position P0) to a direction C2 in which the communication opening 76 is closed. As a result, the communication opening 76 of the small tank 70 is closed by the switching valve 58, and thereafter, until the small flushing mode is completed, the water storage cylinder body 68 and the small tank 70 remain isolated from each other by the switching valve 58 (see states (II) to (VI) in Figure 6B).

[0039] Furthermore, in state (II) of Figure 6B, the float 74 and valve body 36 are raised to their highest position, the drain port 18 of the water storage tank 12 is opened by the raised valve body 36, and the drainage of cleaning water from inside the water storage tank 12 to the drain port 18 begins. Subsequently, as shown in states (III) to (V) of Figure 6B, when the water level W1 in the water storage tank 12 falls below the upper end of the water storage cylinder 62, the water pressure due to the water level W2a in the water storage cylinder body 68 exceeds the water pressure due to the water level W1 in the water storage tank 12 outside it. As a result, the cleaning water in the water storage cylinder body 68 flows out through the outlet hole 72 into the water storage tank 12 outside it. In the states (III) to (V) of Figure 6B, the water level W2a inside the water storage cylinder body 68 is higher than the water level W1 inside the water storage tank 12 outside it, so the cleaning water inside the water storage cylinder 62 continues to flow out from each outlet hole 72. As a result, the water level W2 in the water reservoir 62 gradually decreases, and the float 74 also descends in conjunction with the decrease in water level W2. In the states (III) to (V) of Figure 6B, the water level W2a in the main water reservoir 68 is lower than the water level W2b in the small tank 70, and the water pressure in the small tank 70 is higher than the water pressure in the main water reservoir 68. As a result, the switching valve 58 is pressed in direction C2 by the water pressure inside the small tank 70, which closes the communication opening 76. Therefore, the communication opening 76 of the small tank 70 is closed by the switching valve 58, and the state in which the water storage cylinder body 68 and the small tank 70 are isolated by the switching valve 58 is maintained.

[0040] Then, as shown in state (VI) of Figure 6B, when the valve body 36 comes into contact with the valve seat 66, the drain port 18 is closed, and the drainage of cleaning water from the water storage tank 12 to the drain port 18 is stopped. This terminates the supply of flushing water from the flushing water tank device 2 to the toilet bowl body 8 in light flush mode. At this time, the lowest water level DWL2 in the water storage tank 12 during the small flush mode in state (VI) of Figure 6B (the so-called "dead water line," which is the drainage stop water level) is located above the lowest water level DWL1 in the water storage tank 12 during the large flush mode in state (VI) of Figure 6A. In other words, the amount of cleaning water drained from the water storage tank 12 to the drain outlet 18 in the small cleaning mode will be less than the amount of cleaning water drained from the water storage tank 12 to the drain outlet 18 in the large cleaning mode, by the amount that the minimum water level DWL2 in the small cleaning mode is higher than the minimum water level DWL1 in the large cleaning mode. Incidentally, in the large-scale cleaning mode from state (III) to (VI) in Figure 6A, the first total outflow amount (first water drainage amount) Q1 [L] of the cleaning water from the water reservoir 62 flowing out from the outflow hole 72 into the water storage tank 12 is greater than the second total outflow amount (second water drainage amount) Q2 [L] of the cleaning water from the water reservoir 62 flowing out from the outflow hole 72 into the water storage tank 12 in the small-scale cleaning mode from state (III) to (VI) in Figure 6B (Q1 > Q2).

[0041] According to the drain valve device 1 of the embodiment described above, when starting the flushing of the toilet bowl 4, first, one of the flushing modes, either the large flush mode or the small flush mode, is selected, and then the operating shaft 54 ​​of the drain valve device 1 is raised, causing the valve body 36 to rise (open), and flushing water from the water storage tank 12 is supplied from the drain port 18 to the water conduit 8a of the toilet bowl body 8 of the toilet bowl 4. Then, depending on the selected large or small flush mode, the water level W2 in the water reservoir 62 decreases, and as the water level W2 decreases, the float 74 in the water reservoir 62 descends. As a result, the operating shaft 54 ​​of the drain valve device 1 descends, causing the valve body 36 to descend (close), stopping the supply of flushing water from the water storage tank 12 to the toilet bowl 4, and ending the flushing of the toilet bowl 4. In this case, the first total outflow volume Q1 [L] of cleaning water in the water reservoir 62 that flows out from the outflow hole 72 into the water storage tank 12 in the large cleaning mode is greater than the second total outflow volume Q2 [L] of cleaning water in the water reservoir 62 that flows out from the water storage tank 12 into the water storage tank 12 in the small cleaning mode (Q1 > Q2). This allows the descent speed v2 of the float 74 in small flush mode to be greater than the descent speed v1 of the float 74 in large flush mode (v2>v1). Therefore, the descent time of the float 74 and the opening time of the valve body 36 in the small flush mode can be made shorter than the descent time of the float 74 and the opening time of the valve body 36 in the large flush mode. As a result, by changing the amount of cleaning water (so-called "water drainage amount Q1, Q2") that flows from the water reservoir 62 through the outlet hole 72 to the water storage tank 12, depending on the selected large or small cleaning mode, the descent speeds v1, v2 of the float 74 as the water level W2 in the water reservoir 62 decreases can be changed. Therefore, the flow rate of the cleaning water per unit time (hereinafter referred to as "instantaneous flow rate") [L / min], which affects cleaning performance, can be maintained at a relatively high level even in the small cleaning mode, which uses less cleaning water than the large cleaning mode. In addition, the closing noise generated when the valve body 36 closes the drain port 18 can also be reduced.

[0042] Furthermore, according to the drain valve device 1 of this embodiment, the small tank 70, which is connected to the water storage cylinder body 68 so as to be able to communicate with it, is equipped with a communication opening 76 that communicates with the water storage cylinder body 68, and a switching valve 58 for switching between large and small flushes that opens and closes the communication opening 76. This allows the switching valve 58 to open the communication opening 76 in the large flush mode, thereby connecting the water reservoir body 68 and the small tank 70. On the other hand, the switching valve 58 of the small tank 70 can isolate the water storage cylinder body 68 and the small tank 70 by closing the communication opening 76 in the small flushing mode. As a result, in the large-scale flushing mode, the first total outflow volume Q1 [L] of the flushing water in the water reservoir 62 that flows out from the outflow hole 72 to the water storage tank 12 can be made larger than the second total outflow volume Q2 [L] of the flushing water in the water reservoir 62 that flows out from the outflow hole 72 to the water storage tank 12 in the small-scale flushing mode. Therefore, the descent speed v2 of the float 74 in the small-scale flushing mode can be made larger than the descent speed v1 of the float 74 in the large-scale flushing mode. This makes it possible to shorten the descent time of the float 74 and the opening time of the valve body 36 in the small flush mode compared to the descent time of the float 74 and the opening time of the valve body 36 in the large flush mode. As a result, by changing the amount of cleaning water Q1, Q2 [L] (so-called "water drainage amount Q1, Q2") that flows from the water reservoir 62 to the water storage tank 12 through the outlet hole 72, depending on the selected large cleaning mode or small cleaning mode, the descent speed v1, v2 of the float 74 as the water level in the water reservoir 62 decreases can be changed. Therefore, the instantaneous flow rate [L / min] of the cleaning water, which affects cleaning performance, can be maintained at a relatively high level even in the small cleaning mode, which uses less cleaning water than the large cleaning mode. In addition, the closing noise generated when the valve body 36 closes the drain port 18 can also be reduced.

[0043] Furthermore, according to the drain valve device 1 of this embodiment, if the switching valve 58 for switching between large and small flushes is not rotatable relative to the communication opening 76, but rather is provided so as to be slidable relative to the communication opening 76, then when the communication opening 76 is closed by the switching valve 58, the seal portion in contact with the switching valve 58 and the communication opening 76 is at risk of being damaged due to wear and tear caused by repeated opening and closing sliding of the switching valve 58 relative to the communication opening 76. However, according to the drain valve device 1 of this embodiment, the switching valve 58 is rotatably provided with respect to the communication opening 76, and can be rotated in the direction C1 that opens the communication opening 76 in the large flush mode, and in the direction C2 that closes the communication opening 76 in the small flush mode. This allows for a configuration in which the switching valve 58 slides open and closed relative to the communication opening 76, while reducing the number of parts and avoiding the risk of the switching valve 58 constantly contacting the communication opening 76 regardless of the cleaning mode. Therefore, the risk of damage due to wear or other factors can be reduced to the part (sealing part) that the switching valve 58 contacts when the small tank 70 is closed at the communication opening 76.

[0044] Furthermore, according to the drain valve device 1 of this embodiment, the communication opening 76 of the small tank 70 is provided with a locking portion 78 at its rim that rotatably supports the switching valve 58. As a result, when the switching valve 58 rotates in the direction C2 that closes the communication opening 76 in the small flushing mode and comes into contact with the locking portion 78, the locking portion 78 can reliably restrict the rotation of the switching valve 58. Furthermore, in the small flushing mode, when the switching valve 58 is in contact with the locking portion 78, the switching valve 58 and the rim of the communication opening 76 can be reliably sealed by the locking portion 78, thereby improving the watertightness between the water storage cylinder body 68 and the small tank 70. Therefore, in the small flushing mode, it is possible to reliably prevent the flushing water in the small tank 70 from flowing into the water storage cylinder body 68 through the communication opening 76.

[0045] Furthermore, according to the drain valve device 1 of this embodiment, the switching valve 58 is equipped with a pair of water weights 82 for storing cleaning water, and the bottom surface of the small tank 70 is provided with a pair of auxiliary outlet holes 84 for draining the cleaning water from the small tank. As a result, when the switching valve 58 is in contact with the locking portion 78, the water weight portion 82 can store cleaning water, and the cleaning water in the small tank 70 is discharged from the auxiliary outlet hole 84. Furthermore, as the cleaning water in the small tank 70 flows out through the auxiliary outlet hole 84, the switching valve 58 rotates in a direction that separates it from the locking portion 78 (direction C1 that opens the communication opening 76), allowing the cleaning water in the water weight portion 82 to flow out. Therefore, the series of rotational movements of the switching valve 58 from closing the communication opening 76 of the small tank 70 to opening it can be reliably and smoothly performed by utilizing the change in the water level in the small tank 70 and the change in the amount of washing water stored in the water weight section 82.

[0046] Furthermore, according to the drain valve device 1 of this embodiment, in the initial position P0, the switching valve 58 is in a tilted (horizontal) position and does not contact the locking portion 78, opening the communication opening 76 and not storing cleaning water in the water weight portion 82. During the standby period when no cleaning mode is being performed (see state (I) in Figures 6A and 6B), and during the period when the main cleaning mode is being performed (see state (II) to (VI) in Figure 6A), the switching valve 58 is maintained in the initial position P0, thereby closing the auxiliary outlet hole 84 of the small tank 70 and allowing cleaning water to be stored in the small tank. On the other hand, during the period when the small flush mode is being executed (see states (II) to (VI) in Figure 6B), the switching valve 58 rotates from its initial position P0 in the direction C2 that closes the communication opening 76, and maintains the state of closing the communication opening 76 by contacting the locking portion 78. Subsequently, when the cleaning water in the small tank 70 flows out through the auxiliary outlet hole 84, the switching valve 58 rotates from the state in which the communication opening 76 is closed toward the initial position P0, allowing the cleaning water in the water weight section 82 to flow out, and then returns to the initial position P0. As a result, by efficiently changing the amount of cleaning water Q1 and Q2 (so-called "water drainage amounts Q1 and Q2") that flows from the water reservoir 62 through the outlet hole 72 into the water storage tank 12, depending on the selected large or small cleaning mode, the descent speeds v1 and v2 of the float 74 that occur as the water level W2 in the water reservoir 62 decreases can be efficiently changed.

[0047] Furthermore, according to the drain valve device 1 of this embodiment, as shown in Figures 3 and 5, the upper edge 68b of the water storage cylinder body 68 and the upper edge 70a of the small tank 70 are flush with each other. Furthermore, as shown in Figure 5, when the switching valve 58 is closing the communication opening 76 of the small tank 70, the upper end 58a of the switching valve 58 protrudes above the upper edge of the communication opening 76 or the upper edge 70a of the small tank 70. As a result, when the switching valve 58 is closed, it is possible to reliably prevent the cleaning water in the small tank 70 from overflowing the upper end 58a of the switching valve 58 and flowing into the water storage cylinder body 68. [Explanation of Symbols]

[0048] 1. Drain valve device according to one embodiment of the present invention 2. Washing water tank device 4 Flush toilet 6 Bowl section 8 Toilet bowl 8a Water conduit 10 External tanks 12. Water storage tank (washing water tank) 14 Lid 16 Insulator 18 Drain 20 Water supply equipment 22 Water supply pipe 24 Valve Unit 26 Water supply float 28 Water pipe 30 Lever 32 Operating device 34 Operating levers 36 Valve body 38 Lifting mechanism 40 Outer rotating shaft 42 Inner rotation axis 44 Rotating main shaft 46 Cylindrical rotating part 48. First oscillating lever 50 Second oscillating lever 52 First Jade Chain 54 Operating shaft 56 Second Jade Chain 58 Switching valve (partition section) for switching between large and small flushing. 58a Upper end of the switching valve 60 Drain hole forming part 62 Water bottles 62a Side wall part 64 Overflow pipe 66 valve seats 68 Water storage tank body 68a Side wall of the water storage tank body 68b Upper edge of the water storage tank body 70 Small Tank 70a Upper edge of small tank 72 Outlet holes 74 Floats 76 Communication opening 78 Locking part 78a Upper end of the locking part 80 Valve body 82 Water weight section 82a Open end 84 Auxiliary outflow holes A1 Rotational center axis A2 Rotation center axis DWL1 Minimum water level in the water tank during full flush mode Minimum water level in the water tank during DWL2 minor flush mode C1 The switching valve for switching between large and small flushes opens the communication opening in the direction. C2 The switching valve for switching between large and small flushes closes the communication opening. P0 Initial position of the switching valve for switching between large and small flushes. Q1. In full flush mode, what is the total outflow volume and water drainage volume (first total outflow volume) of the flushing water in the reservoir that flows out of the outlet hole into the reservoir tank when the valve is open? Q2. In the small flushing mode, what is the total outflow volume and water drainage volume (second total outflow volume) of the flushing water in the reservoir that flows out of the outlet hole into the reservoir tank when the valve body is open? v1 Water level in the reservoir and float descent speed in full flush mode v2 Water level in the reservoir and float descent speed in light flush mode Water level in W1 storage tank Water level inside W2 reservoir W2a Water level inside the water reservoir W2b Water level in the small tank

Claims

1. A drain valve device installed in a flush water tank that supplies flushing water to a flush toilet, A valve body that opens and closes the drain port located at the bottom of the above-mentioned cleaning water tank, The valve body is provided at the lower end, and the operating shaft opens and closes the valve body by moving up and down, A water storage cylinder through which the above-mentioned operating shaft is inserted in the vertical direction and which stores a portion of the cleaning water in the above-mentioned cleaning water tank, the water storage cylinder having an outlet hole formed therein for the cleaning water inside to flow out to the outside, It has a float placed inside the water reservoir that applies buoyancy obtained from the cleaning water inside the water reservoir to the operating shaft, The above operating shaft and valve body are configured to descend in conjunction with the float as the water level in the reservoir decreases, thereby closing the drain port. From the time the valve body opens until it closes, either a large flush mode, in which the flushing water in the flushing water tank is supplied to the toilet bowl from the drain outlet at a first flushing water volume, or a small flush mode, in which the flushing water is supplied at a second flushing water volume less than the first flushing water volume, can be selectively executed. In the above-mentioned large-scale cleaning mode, the first total outflow amount of cleaning water in the water reservoir that flows out from the outflow hole to the cleaning water tank is greater than the second total outflow amount of cleaning water in the water reservoir that flows out from the outflow hole to the cleaning water tank in the above-mentioned small-scale cleaning mode. The above-mentioned water storage cylinder comprises a water storage cylinder body having the above-mentioned outlet hole, and a small tank connected to the water storage cylinder body so as to be able to communicate with it, and this small tank comprises a communication opening that communicates with the water storage cylinder body, and a partition that opens and closes the communication opening, The drain valve device is characterized in that the partition section connects the water storage cylinder body and the small tank by opening the communication opening in the large washing mode, and isolates the water storage cylinder body and the small tank by closing the communication opening in the small washing mode.

2. The drain valve device according to claim 1, wherein the partition portion is rotatably provided with respect to the communication opening, rotates in a direction that opens the communication opening in the large washing mode, and rotates in a direction that closes the communication opening in the small washing mode.

3. The drain valve device according to claim 2, wherein the above-mentioned communication opening is provided with a locking portion on its rim that rotatably supports the above-mentioned partition portion, and in the above-mentioned small flushing mode, the locking portion restricts the rotation of the partition portion by rotating the partition portion in a direction that closes the communication opening and contacting the locking portion.

4. The partition section further includes a water weight section for storing cleaning water, and the small tank further includes an auxiliary outlet hole formed on its bottom surface for draining the cleaning water from the small tank. The drain valve device according to claim 3, wherein when the partition portion is in contact with the locking portion, the water weight portion is capable of storing cleaning water and the auxiliary outlet hole of the small tank is open, and when the cleaning water in the small tank flows out from the auxiliary outlet hole, the partition portion rotates in a direction away from the locking portion and the cleaning water in the water weight portion is discharged.

5. In its initial position, the partition does not contact the locking portion, leaving the communication opening open and no cleaning water is stored in the water weight portion. During the standby period when no cleaning mode is being performed and during the period when the above-mentioned large cleaning mode is being performed, the partition is maintained in the initial position, thereby closing the auxiliary outlet hole of the small tank and allowing cleaning water to be stored in the small tank. On the other hand, during the period in which the small cleaning mode described above is being performed, the partition portion rotates from the initial position to contact the locking portion, thereby maintaining the state in which the communication opening is closed. After the cleaning water in the small tank flows out from the auxiliary outlet hole, the partition portion rotates toward the initial position, allowing the cleaning water in the water weight portion to flow out, and then returns to the initial position, as described in claim 4.

6. The drain valve device according to any one of claims 1 to 5, wherein the upper edge of the water storage cylinder body and the upper edge of the small tank are flush with each other, and when the partition closes the communication opening, the upper end of the partition protrudes above the upper edge of the communication opening or the upper edge of the small tank.

7. A washing water tank device equipped with a drain valve device according to any one of claims 1 to 6 above.

8. A flush toilet equipped with the flushing water tank device described in claim 7 above.

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