Drain valve device, water storage tank device equipped with same, and flush toilet equipped with same

Abstract

To provide a drain valve device that increases reliability in a cleaning water supply capability, a water storage device, and a flush toilet bowl.SOLUTION: A drain valve device includes: a valve body 42 that opens / closes a drain water port; a float structure 48 that is mounted to the valve body and lowers the valve body in conjunction with descent of a water level in a water storage tank by buoyant force generated in an internal space; and a valve body lower float additionally-provided part 72 that forms an additionally-provided internal space 74 by being mounted to protrude to a lower side relative to the valve body. In the valve body lower float additionally-provided part, a fitting hole 78 that fits into a mounting part of the float structure is formed, the fitting hole communicates with the additionally-provided internal space in the valve body lower float additionally-provided part. Furthermore, in the valve body lower float additionally-provided part 72, an opening part 72b that allows cleaning water flowed into the additionally-provided internal space to flow out, and in the opening part 72b of the valve body lower float additionally-provided part, an angular shape is formed to facilitate reduction in surface tension of the cleaning water that comes into contact with the opening part.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a drain valve device, a water storage tank device equipped with the same, and a flush toilet equipped with the water storage tank device. [Background technology]

[0002] Conventionally, as shown in Patent Document 1, there have been known drain valve devices that have a valve body below-the-valve float addition section below the valve body and that can increase the flow rate of flush water drained from the full water level to the dead water level during the drainage operation of the water storage tank device, and water storage tank devices equipped with this drain valve device.

[0003] In such conventional drain valve devices, air stored in the internal space inside the float extension section below the valve body creates buoyancy in the float extension section below the valve body, delaying the timing of closing the valve body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-133246 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, there are cases where cleaning water flows into the interior of the float attachment portion below the valve body of such conventional drain valve devices, and when cleaning water flows into the interior of the float attachment portion below the valve body, the air stored in the internal space of the float attachment portion below the valve body is reduced, resulting in the valve body closing at an earlier time than the expected closing timing.

[0006] The present invention has been made to solve problems that have existed in the past, and its object is to provide a drain valve device that can improve the performance of draining flush water from the float addition section below the valve body and increase the reliability of flush water supply capacity, a water storage tank device equipped with this drain valve device, and further a flush toilet equipped with this water storage tank device. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention is a drain valve device attached to a water storage tank for storing flush water, comprising: a valve body that is attached above a drain outlet provided on the bottom surface of the water storage tank and moves up and down to open and close the drain outlet; a float structure that is attached to the valve body and causes the valve body to descend in conjunction with a drop in the water level in the water storage tank by buoyancy generated in the internal space; and a valve body below float extension portion that is provided so as to protrude inwardly of the valve body and downwardly from the valve body, thereby forming an extended internal space, wherein the valve body below float extension portion has a fitting hole that fits with the mounting portion of the float structure, and the fitting hole is connected to the extended internal space within the valve body below float extension portion, and further, the valve body below float extension portion has an opening formed therein to allow flush water that has flowed into the extended internal space to flow out, and the opening of the valve body below float extension portion is formed in an angular shape that makes it easier to reduce the surface tension of the flush water that comes into contact with the opening. According to one embodiment of the present invention configured in this manner, even if flush water flows into the additional internal space from the fitting hole or opening, the angular shape of the opening makes it easier to reduce the surface tension of the flush water in contact with the opening, improving the flush water discharge performance from the valve body below float additional part. As a result, flush water in contact with the opening in the valve body below float additional part remains inside the opening due to surface tension and does not flow out, the buoyancy generated by the additional internal space is reduced, and the valve body is prevented from closing earlier than the expected valve closing timing. Therefore, it is possible to provide a drain valve device that can increase the flow rate of flush water drained from the full water level to the dead water level during the drainage operation of the water storage tank device and improve the reliability of the flush water supply capacity, without changing the size of the drain valve device or the size of the water storage tank.

[0008] In the present invention, the opening of the float additional portion below the valve body is preferably formed in a polygonal shape. According to one embodiment of the present invention configured in this way, the opening is formed in a polygonal shape, so that the surface tension of the flush water in contact with the opening can be more easily reduced by multiple, for example, three or more corners, and the flush water discharge performance from inside the valve body below float additional part can be further improved. As a result, flush water in contact with the opening in the valve body below float additional part remains inside the opening due to surface tension and does not flow out, the buoyancy generated by the additional internal space is reduced, and the valve body can be more effectively prevented from closing at a timing earlier than the expected valve closing timing. Therefore, it is possible to provide a drain valve device that can increase the flow rate of flush water discharged from the full water level to the dead water level in the drainage operation of the water storage tank device and further improve the reliability of the flush water supply capacity without changing the size of the drain valve device or the size of the water storage tank.

[0009] In the present invention, preferably, a plurality of fitting holes are provided in the valve body below float additional portion, and are provided at positions around the opening facing each side of the opening. According to one embodiment of the present invention configured in this manner, flushing water that flows into the expanded internal space through the fitting hole can be made to flow out more easily from each side of the opposing opening, thereby improving the discharge performance of flushing water from the float expansion section below the valve body.

[0010] In the present invention, preferably, the fitting holes of the valve body below float additional portion form two sets arranged at opposing positions across the opening, and an opposing line connecting the opposing fitting holes of the first set intersects perpendicularly with an opposing line connecting the opposing fitting holes of the second set. According to one embodiment of the present invention configured in this manner, the opposing line connecting the opposing fitting holes of the first set perpendicularly intersects with the opposing line connecting the opposing fitting holes of the second set, so that flush water flowing in from each fitting hole can easily enter the opening after colliding with flush water flowing in from a fitting hole at an opposing position across the opening. Therefore, the performance of discharging flush water from the valve body below float additional section can be further improved.

[0011] In the present invention, the opening of the valve body below float additional portion is preferably formed in a rectangular shape. According to one embodiment of the present invention configured in this manner, the opening can be formed relatively easily using four straight lines, which makes it possible to improve the productivity of the additional float installation portion below the valve body and reduce the manufacturing costs.

[0012] The water storage tank device of the present invention comprises a drain valve device and a water storage tank for storing flush water. According to one embodiment of the present invention configured in this manner, the water storage tank device is equipped with a drain valve device and a water storage tank, and a water storage tank device can be provided that can increase the flow rate of flush water drained from the full water level to the dead water level during the drainage operation of the water storage tank device without changing the size of the drain valve device or the size of the water storage tank, and that further improves the reliability of the flush water supply capacity.

[0013] The flush toilet of the present invention is equipped with a water storage tank device. According to one embodiment of the present invention configured in this manner, the flush toilet is equipped with the above-mentioned water storage tank device, and it is possible to increase the flow rate of flush water drained from the full water level to the dead water level during the drainage operation of the water storage tank device, without changing the size of the drain valve device or the size of the water storage tank, and it is possible to provide a flush toilet with more reliable flushing performance. Effect of the Invention

[0014] The drain valve device, water storage tank device, and flush toilet of the present invention can improve the reliability of flush water supply capacity. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a side cross-sectional view showing a flush toilet according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Diagram 3] 1 is a perspective view of a drain valve device according to an embodiment of the present invention; FIG. [Figure 4] 1 is a perspective view showing a base and an overflow pipe of a drain valve device according to an embodiment of the present invention; [Diagram 5] 2 is a cross-sectional view showing a base and an overflow pipe of a drain valve device according to one embodiment of the present invention. FIG. [Figure 6] 1 is a perspective view showing the valve body, float, and descent start timing adjustment mechanism of a drain valve device according to one embodiment of the present invention, viewed obliquely from above. FIG. [Figure 7] 1 is an oblique view showing the valve body, float, valve body below float additional portion, and descent start timing adjustment mechanism of a drain valve device according to one embodiment of the present invention, viewed diagonally from below. FIG. [Figure 8] 2 is a cross-sectional view showing the valve body, float, valve body below float additional portion, and descent start timing adjustment mechanism of a drain valve device according to one embodiment of the present invention. FIG. [Figure 9] 4 is a perspective view showing a guide portion that guides a valve body of the drain valve device according to one embodiment of the present invention. FIG. [Figure 10]1 is a perspective view showing the inner wall of a water storage portion of a descending start timing initiation mechanism of a drain valve device according to one embodiment of the present invention; FIG. [Figure 11] 1 is a perspective view showing a float additional portion below the valve body of a drain valve device according to one embodiment of the present invention, as viewed obliquely from above. FIG. [Figure 12] 1 is a perspective view showing an additional float portion below the valve body of a drain valve device according to one embodiment of the present invention, as viewed obliquely from below. FIG. [Figure 13] 1 is a central cross-sectional view of a modified example of a float attachment portion below the valve body of a drain valve device according to an embodiment of the present invention; [Figure 14] 1 is a cross-sectional view showing a state before drainage begins of a drain valve device according to an embodiment of the present invention. [Figure 15] 1 is a cross-sectional view showing a state during drainage of a drain valve device according to an embodiment of the present invention. FIG. [Figure 16] 1 is a cross-sectional view showing a state immediately after the valve body closes the drain outlet and drainage has finished in a drain valve device according to one embodiment of the present invention. FIG. [Figure 17] 1 is a schematic diagram showing the positional relationship between the fitting hole and the opening of the float attachment portion below the valve body of a drain valve device according to one embodiment of the present invention, viewed from above the float attachment portion below the valve body. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A drain valve device, a water storage tank device, and a flush toilet according to one embodiment of the present invention will be described below with reference to the accompanying drawings.

[0017] A drain valve device, water storage tank device, and flush toilet according to one embodiment of the present invention will be described with reference to Figures 1 and 2. First, a flush toilet according to one embodiment of the present invention will be described with reference to Figure 1. Figure 1 is a side cross-sectional view showing a flush toilet according to one embodiment of the present invention, and Figure 2 is a cross-sectional view taken along line AA in Figure 1.

[0018] As shown in Figure 1, a flush toilet 1 according to one embodiment of the present invention comprises a toilet body 2 that is placed on the floor of a toilet room, and a water storage tank device 4 that is installed at the upper rear of this toilet body 2 and stores flush water to be supplied to the toilet body 2. The term "flush water" used in this embodiment means water that can be used to flush the toilet body. Flush water is ordinary water, such as tap water, and is not limited to water containing specific components.

[0019] The toilet body 2 comprises a bowl portion 6 for receiving waste, a water conduit 8 for directing flushing water supplied from the water storage tank device 4 to the bowl portion 6, and a drain trap pipe 10 whose inlet is connected to the bottom of the bowl portion 6 and which discharges waste within the bowl portion 6 to an external drain pipe (not shown).

[0020] The bowl portion 6 comprises a rim portion 12 which overhangs inward at the upper edge, a first water outlet 7 which is provided on the left side of the toilet bowl about this rim portion 12 and which discharges flushing water supplied from a water conduit 8 towards the front of the toilet bowl, and a second water outlet 16 which is provided on the left side of the toilet bowl above the water level and which discharges flushing water supplied from the water conduit 8 laterally.

[0021] Drain trap pipe 10 has an ascending passage portion that extends upward from its inlet, and a descending passage portion that extends downward from the end of the ascending passage portion and is connected to an external drain pipe (not shown). Flush water for forming a water seal is stored from bowl portion 6 to the ascending passage portion of drain trap pipe 10. The stored flush water is called "stored water", and the water surface of the stored water is the stored water surface.

[0022] Flush toilet 1 is of the so-called wash-down type, in which waste is washed away by the running water action caused by the drop in flush water within bowl portion 6. In flush toilet 1, flush water discharged forward from first outlet 7 descends while swirling to clean bowl portion 6, and further, flush water discharged from second outlet 16 swirls vertically, agitating waste and pushing it out into drain trap pipe 10. The present invention is not limited to this wash-down type, and may be a flush toilet of another type, such as a siphon type.

[0023] Next, the water storage tank device will be described with reference to Fig. 2. As shown in Fig. 2, the water storage tank device 4 includes a water storage tank 18 for storing flush water, a lid 20 for the water storage tank 18, a water supply device 22 provided in the water storage tank 18, and a drain valve device 24 attached to the water storage tank 18.

[0024] As shown in Fig. 2, the water tank 18 is, for example, made of ceramic, and is a generally rectangular container with an open top. The opening at the top is usually closed by, for example, a ceramic lid 20 (see Fig. 1). Note that the lid 20 is not shown in Fig. 2.

[0025] A lever handle 26 is provided on the outer surface of the water tank 18. The lever handle 26 rotates around the axis of its base 26a. In addition, a substantially L-shaped spindle 28 that extends substantially horizontally into the water tank 18 and has a tip that is bent downward is connected to the lever handle 26 coaxially with the rotation axis of the lever handle 26. The spindle 28 rotates to the front side and the back side in the figure by rotating the lever handle 26.

[0026] The tip of the spindle 28 is located almost directly above the drain valve device 24. One end of a ball chain 30, which is a connecting member, is connected to the tip of the spindle 28. The other end of the ball chain 30 is connected to a float structure 48 of the drain valve device 24, which will be described later.

[0027] A circular drain outlet 32 ​​is formed in the bottom surface of the water storage tank 18, and this drain outlet 32 ​​communicates with the water conduit 8 (see FIG. 1) so as to supply flush water to the water conduit 8. The drain outlet 32 ​​is opened and closed by a drain valve device 24.

[0028] As shown in Fig. 2, a water supply device 22 is provided inside the water storage tank 18. The water supply device 22 includes a water supply pipe 34, a small tank 36, and a water supply float 38. The water supply pipe 34 is connected to a water supply source (not shown) outside the water storage tank 18, and extends upward from the bottom surface of the water storage tank 18. In addition, a water supply port 34a is provided at the bottom of the water supply pipe 34, which supplies flush water into the water storage tank 18.

[0029] In addition, a diaphragm-type water supply valve (not shown) is provided at the upper part of the water supply pipe 34, and this water supply valve switches between supplying and stopping the supply of cleaning water from the water supply pipe 34 into the water storage tank 18.

[0030] The small tank 36 is a substantially rectangular container that forms a water storage area inside, and is detachably installed to the side of the water supply pipe 34. The small tank 36 is provided with a check valve (not shown) that opens and closes an opening (not shown) provided on the bottom surface. The water supply float 38 is disposed in the small tank 36, and moves up and down depending on the level of flush water stored in the small tank 36.

[0031] The water supply float 38 is connected to a water supply valve (not shown) via a swinging body 40, and opens and closes the water supply valve by moving up and down. Specifically, the water supply float 38 descends in conjunction with the drop in the water level in the small tank 36, as flush water stored in the small tank 36 is drained from an opening (not shown) formed in the bottom surface. The water supply valve is opened by the water supply float 38 descending, and flush water is supplied into the water storage tank 18 from the water supply port 34a.

[0032] Next, the drain valve device 24 will be described with reference to FIGS. Figure 3 is an oblique view of a drain valve device according to one embodiment of the present invention, Figure 4 is an oblique view showing the base and overflow pipe of a drain valve device according to one embodiment of the present invention, Figure 5 is a cross-sectional view showing the base and overflow pipe of a drain valve device according to one embodiment of the present invention, Figure 6 is an oblique view showing the valve body, float, and descent start timing adjustment mechanism of a drain valve device according to one embodiment of the present invention, viewed diagonally from above, Figure 7 is an oblique view showing the valve body, float, additional float portion below the valve body, and descent start timing adjustment mechanism of a drain valve device according to one embodiment of the present invention, viewed diagonally from below, and Figure 8 is a cross-sectional view showing the valve body, float, additional float portion below the valve body, and descent start timing adjustment mechanism of a drain valve device according to one embodiment of the present invention.

[0033] The drain valve device 24 is a so-called direct acting type drain valve device that is provided above the drain outlet 32 ​​and has a valve body 42 that moves up and down in the vertical direction to open and close the drain outlet 32. Note that the drain valve device 24 may also be a so-called flapper type drain valve device in which the valve body 42 moves up and down to open and close the drain outlet 32.

[0034] The drain valve device 24 includes a base 44 and an overflow pipe 46. The base 44 is disposed substantially directly above the drain outlet 32. The base 44 includes a plurality of pillars 44a arranged concentrically about the center of the drain outlet 32 ​​at a predetermined interval, and a cylindrical connecting portion 44b provided at the bottom is screwed into the drain outlet 32. A drain space 44c communicating with the drain outlet 32 ​​is formed below the base 44. Flush water passes through the drain space 44c from an opening 44d between the pillars 44a, and is then drained from the drain outlet 32.

[0035] The overflow pipe 46 is provided integrally with the base 44 on the side of the base 44. The overflow pipe 46 is formed in a cylindrical shape with an upper end opening facing upward. The lower end opening of the overflow pipe 46 opens sideways, approximately perpendicular to the upper end opening, and communicates with the drain space 44c. The overflow pipe 46 is provided to prevent flush water from overflowing from the water storage tank 18. When the water level in the water storage tank 18 exceeds the height of the upper end opening of the overflow pipe 46, the flush water flows into the overflow pipe 46 and is drained to the drain outlet 32.

[0036] The drain valve device 24 includes a valve body 42 that is attached above the drain port 32 provided on the bottom surface of the water storage tank 18 and moves up and down to open and close the drain port 32, a float structure 48 that is attached to the valve body 42 and uses buoyancy generated in an internal space 49 to lower the valve body 42 in conjunction with a drop in the water level in the water storage tank 18, a descent start timing variable mechanism 50, and a valve body below float additional part 72 that is attached so as to protrude radially inward of the valve body 42 and downward from the valve body 42, thereby adding to the float structure 48. The drain valve device 24 is formed so that the valve body 42 and the valve body below float additional part 72 are raised above the valve seat 43 when drainage starts, even for the smaller set drainage amount of the drainage amounts set in multiple stages from the drain port.

[0037] The valve body 42 is formed in a disk shape, and has a rubber seal portion 42a on the lower surface facing the drain outlet 32. The valve body 42 is provided in a base 44 so as to be movable up and down in a predetermined range, and closes the drain outlet 32 ​​by abutting against a valve seat 43 provided on the base 44 at the lowest position of the movable range. The valve body 42 is formed in an annular shape, and a space is formed on the inside in the radial direction. The valve body 42, together with the seal portion 42a, forms an annular sealing surface.

[0038] The float structure 48 includes a cylindrical inner tube 48a with a closed upper end, and an outer tube 48b with an open upper end outside the inner tube 48a. The lower ends of the inner tube 48a and the outer tube 48b are closed by a lower surface 48c. Furthermore, the lower ends of the inner tube 48a and the outer tube 48b are connected to the valve body 42 and are provided integrally with the valve body 42. When the water level in the water storage tank 18 drops to a predetermined height, the float structure 48 descends in conjunction with the subsequent drop in the water level. The inner tube 48a of the float structure 48 is formed so that its lower portion is open. The float structure 48 forms an internal space 49 inside the inner tube 48a. Therefore, the float structure 48 is formed so that it receives an upward buoyancy from the air stored in the internal space 49 of the float structure 48 when wash water is present around it. The float structure 48 is formed so that, by forming its internal space 49 into a space of volume C1, it generates a predetermined amount of buoyancy when draining water, as described below.When the water level in the water storage tank 18 drops to a predetermined height, the float structure 48 descends in conjunction with the subsequent drop in the water level, thereby enabling drainage to be performed down to a predetermined dead water level DWL1 (see Figure 16).

[0039] The variable descent start timing mechanism 50 is a buoyancy adjustment mechanism for the float structure 48, and is provided in the area around and above the float structure 48. The variable descent start timing mechanism 50 is intended to change (make variable) the water level in the water tank 18 when the valve body 42 and the float structure 48 start to descend in conjunction with the drop in the water level in the water tank 18, in response to the buoyancy generated by the float structure 48.

[0040] By placing the descent start timing variable mechanism 50 on the float structure 48, the height of the float structure 48 from the drain outlet 32 ​​can be kept constant while the water level at which the valve body 42 and float structure 48 begin to descend can be changed.

[0041] Next, the specific structure of the descent start timing variable mechanism 50 will be described with reference to Figures 3 to 10. Figure 9 is a perspective view showing a guide portion that guides the valve body of the drain valve device according to one embodiment of the present invention, and Figure 10 is a perspective view showing the inner wall of the water storage portion of the descent start timing initiation mechanism of the drain valve device according to one embodiment of the present invention. Here, the dead water levels (DWL1 to DWL3) refer to the flush water levels in the water storage tank when flush water discharge is stopped (see FIG. 16). Note that the dead water level at a low position is called the "low DWL," and the dead water level at a high position is called the "high DWL."

[0042] The descent start timing variable mechanism 50 includes a water storage section 52 and an adjustment section 54. The water storage section 52 is formed in the area around and above the float structure 48. Specifically, the water storage section 52 includes a donut-shaped container with an open top formed by the inner tube 48a, the outer tube 48b, and the lower surface 48c of the float structure 48. Furthermore, the water storage section 52 includes a cylindrical side wall 56 with an open upper end and lower end that is inserted into the inside of the outer tube 48b from above and fixed to the inside of the outer tube 48b. This side wall 56 is formed around the entire circumference, and flush water can be stored up to the upper edge of the side wall 56. In this way, the water storage section 52 is formed by the inner tube 48a, the outer tube 48b, the lower surface 48c, and the side wall 56 of the float structure 48, and forms a water storage area for storing flush water in the internal space formed by them (the area around and above the float structure 48).

[0043] Next, the adjustment unit 54 of the descent start timing variable mechanism 50 will be described with reference to Fig. 3 to Fig. 10. The adjustment unit 54 of the descent start timing variable mechanism 50 includes a vertical groove 58 extending in the axial direction (up and down direction) of the float structure 48, which is provided so as to penetrate the outer peripheral surface and the inner peripheral surface of the outer cylinder 48b of the float structure 48, and a horizontal groove 60 extending horizontally to the left of the vertical groove 58. The adjustment unit 54 further includes a protrusion 62 provided on the outer peripheral surface of the side wall 56, which can be inserted into the vertical groove 58 and the horizontal groove 60 of the outer cylinder 48b of the float structure 48. Here, a plurality of horizontal grooves 60 (specifically, five) are provided at positions of different heights along the axial direction of the float structure 48 at predetermined intervals. In this regard, lines 1 to 5 extending horizontally (horizontally) are drawn on the surface of the side wall 56, corresponding to the positions of the five lateral grooves 60 of the outer tube 48b of the float structure 48. When the protrusion 62 is inserted into a particular lateral groove 60, the line at the corresponding position is located just above the upper edge of the outer tube 48b and can be seen from the outside (see Figure 10).

[0044] In this embodiment, a convex portion 62 is formed on the side wall 56 of the water storage portion 52, and a vertical groove 58 and a horizontal groove 60 are formed on the outer tube 48b of the float structure 48, but conversely, a vertical groove and a horizontal groove may be formed on the side wall 56 of the water storage portion 52, and a convex portion may be formed on the outer tube 48b of the float structure 48.

[0045] Here, the guide portion 64 of the drain valve device 24 will be described with reference to Figs. 2 and 9. The guide portion 64 is provided on the base 44. As shown in Fig. 2, the guide portion 64 is formed in a cylindrical shape into which the outer tube 48b of the float structure 48 can be inserted. Guide grooves 66 that protrude outward and extend in the vertical direction are formed at two opposing locations on the outer circumferential surface of the guide portion 64. The wall portion 61 formed on the outside of the outer tube 48b of the float structure 48 is inserted into the guide grooves 66 of the guide portion 64 via a small gap, so that the vertical movement of the water storage portion 52 is guided. The guide portion 64 stabilizes the vertical movement of the valve body 42.

[0046] As shown in FIG. 9, two openings 68 are formed on both sides of one guide groove 66 of the guide portion 64, extending vertically along the guide groove 66. The openings 68 are formed in a substantially rectangular shape. Since the openings 68 are formed in the guide portion 64, when excess flush water that exceeds the set water storage amount is present inside the guide portion 64, the excess flush water can be discharged from the openings 68. This stabilizes the water storage amount in the water storage portion 52. In addition, since the wall portion 61 formed on the outside of the outer tube 48b of the water storage portion 52 is inserted into the guide groove 66 extending vertically of the guide portion 64, the circumferential movement of the valve body 42 and the float structure 48 is restricted.

[0047] Here, the area of ​​the opening 68 is formed to be large enough that the level of flush water in the guide portion 64 drops at approximately the same speed as the level of flush water in the water storage tank 18 .

[0048] The variable descent start timing mechanism 50 can set the dead water level at a relatively high position by adjusting the position where the convex portion 62 is inserted into the lateral groove 60 to a high position, and conversely, can set the dead water level at a relatively low position by adjusting the position where the convex portion 62 is inserted into the lateral groove 60 to a low position. The variable descent start timing mechanism 50 can adjust the protruding height of the side wall 56 of the water storage section 52 by adjusting the height of the convex portion 62 relative to the lateral groove 60. For example, in a drain valve device 24 in which the dead water level is set at a relatively high position, the convex portion 62 of the side wall 56 of the water storage portion 52 is inserted into the uppermost lateral groove 60 of the outer cylinder 48b of the float structure 48, and the side wall 56 is at the highest protruding position. At this time, the amount of flush water discharged from the drain port 32 is at a minimum.

[0049] From this state where the convex portion 62 of the side wall 56 of the water storage portion 52 is inserted into the uppermost horizontal groove 60 of the outer tube 48b of the float structure 48, the side wall 56 is rotated clockwise as viewed from above to move the convex portion 62 horizontally to the vertical groove 58, the side wall 56 is then pushed from above to move it down to the lowermost horizontal groove 60, and the side wall 56 is further rotated counterclockwise as viewed from above to insert the convex portion 62 into the lowermost horizontal groove 60, whereby the protruding height of the side wall 56 of the water storage portion 52 is at its lowest position. At this time, the amount of flush water discharged from the drain port 32 is at its maximum. At this time, in the drain valve device 24, a relatively low dead water level is set.

[0050] Next, referring to FIG. 6, the string attachment portion for attaching the ball chain 30, which is a connecting member, to the float structure 48 will be described. A ball chain attachment portion 70, which is a connecting member attachment portion for attaching the ball chain 30, is provided at approximately the center of the upper surface of the float structure 48. This ball chain attachment portion 70 includes a pair of vertical members 70a extending in the up-down direction and a horizontal member 70b connecting these vertical members 70a. The ring portion 30a at the lower end of the ball chain 30 is inserted into this horizontal member 70b. The ring portion 30a at the lower end of this ball chain 30 extends approximately parallel to the inner side surfaces 70c of the vertical members 70a. Therefore, the inner side surfaces 70c of the vertical members 70a function as a rotation restricting portion that restricts the rotation direction of the ring portion 30a of the ball chain 30 to one direction. In this way, the inner surface 70c of the vertical member 70a restricts the rotation direction of the ring portion 30a of the ball chain 30 to one direction, thereby preventing interference between the ball chain 30 and components inside the water tank and tangling of the ball chain 30 itself.

[0051] Next, a float additional portion below the valve body of the drain valve device according to one embodiment of the present invention will be described with reference to Figs. 7, 8, and 11 to 13. Figure 11 is an oblique view showing the valve body below float additional portion of a drain valve device according to one embodiment of the present invention, as viewed diagonally from above; Figure 12 is an oblique view showing the valve body below float additional portion of a drain valve device according to one embodiment of the present invention, as viewed diagonally from below; and Figure 13 is a central cross-sectional view of a modified example of the valve body below float additional portion of a drain valve device according to one embodiment of the present invention.

[0052] The valve body lower float additional part 72 has a circular outer shape in a plan view. The valve body lower float additional part 72 is formed in a dish shape, and the upper part is open upward. In other words, the valve body lower float additional part 72 forms a cylindrical cap shape, and forms a dome-shaped protrusion that protrudes further downward from the lower surface 42b (back surface) of the valve body 42. The valve body lower float additional part 72 has a circular bottom part 72a that protrudes downward in a platform shape. Therefore, the valve body lower float additional part 72 forms an additional internal space 74 inside the dish shape on the inside. That is, when the valve body lower float additional part 72 is attached to the inside side of the valve body 42 and the lower side of the valve body 42, the internal space 49 can be added to the inside side of the valve body 42 and the lower side of the valve body 42. The valve body lower float additional part 72 is formed on the radially inner side of the outer periphery of the valve body 42. The additional internal space 74 is formed in a substantially cylindrical shape inside the valve body below float additional part 72. The additional internal space 74 forms a rectangular cross-sectional shape in the central cross section. The additional internal space 74 forms a space of volume C2. Therefore, with the valve body below float additional part 72 attached, the float structure 48 and the valve body below float additional part 72 have a volume of C1+C2 and are subjected to a buoyancy corresponding to the volume of C1+C2. When the valve body 42 is closed, the valve body below float additional part 72 is located in the air below the valve body 42 and on the drain port 32 side.

[0053] The valve body lower float additional part 72 is formed with a fitting hole 78 that fits with the mounting part 76 of the float structure 48, and the fitting hole 78 communicates with the additional internal space 74 in the valve body lower float additional part 72. The fitting holes 78 are formed on the outer part of the valve body lower float additional part 72. The fitting holes 78 are arranged at equal intervals on a circumference of the same radius centered on the center of the opening 72b. As shown in FIG. 8 and other figures, the fitting holes 78 form a passage in the hole part that extends in the vertical direction from the outside side to the inside side of the valve body lower float additional part 72 (the mounting part 76 passes through this passage and fits into the fitting hole 78), and the upper end (inner end) of the passage communicates with the additional internal space 74. The mounting part 76 forms a claw part that protrudes outward. The fitting hole 78 forms an engagement part that engages with the claw part of the mounting part 76.

[0054] When the valve body below float additional part 72 is attached to the lower part of the valve body 42, the additional internal space 74 and the internal space 49 are connected. In other words, when the valve body below float additional part 72 is attached to the lower part of the valve body 42, the float structure 48 is expanded, and the float structure 48 and the valve body below float additional part 72 can store air by the volume C1 of the float structure 48 plus the volume C2 of the additional internal space. Therefore, by attaching the valve body below float additional part 72, the float structure 48 is in an expanded state. The valve body below float additional part 72 is attached to the valve body 42 and the float structure 48, and moves up and down integrally therewith.

[0055] The valve body below float additional part 72 has an opening 72b formed therein for allowing flushing water flowing into the above-mentioned additional internal space to flow out. The opening 72b is formed in the center of the bottom 72a of the valve body below float additional part 72. This allows air and flushing water to pass through the opening 72b and flow into the additional internal space 74 and the internal space 49. The float structure 48 and the valve body below float additional part 72 are formed so that, in a state where flushing water is present around them, the air stored in the internal space 49 of the float structure 48 and the additional internal space 74 exerts an even greater upward buoyancy than when only the internal space 49 of the float structure 48 is provided. In addition, since the float additional part 72 below the valve body can generate buoyancy by the air stored in the additional internal space 74 formed under the valve body 42, even if the flush water level drops to the height of the valve body 42, the float additional part 72 below the valve body, which is located below the water level, can reliably generate buoyancy. In other words, even at a water level lower than the conventional level, sufficient buoyancy can be generated in the float structure 48 and the float additional part 72 below the valve body, and the descent of the valve body 42 can be delayed to drain flush water to a lower dead water level. Since the float additional part 72 below the valve body is almost always located below the water level, the size of the float additional part 72 below the valve body can generate buoyancy efficiently and add it to the buoyancy of the float structure 48.

[0056] The opening 72b of the valve body lower float additional part 72 is formed in an angular shape that makes it easier to reduce the surface tension of the cleaning water at the opening 72b. The opening 72b is formed in an angular shape that has a corner at least at one part of the entire edge of the edge part that forms the opening. The opening 72b may be formed with a corner on the outside or inside that suppresses the generation of a relatively large surface tension at one point of the edge and makes it easier to reduce the surface tension. The corner is formed facing outward, but it may be formed facing inward, upward, or downward. The opening 72b is not limited to a corner on one horizontal plane, and may have a three-dimensional corner, that is, a corner formed in the up and down directions. For example, a part of the edge of the opening 72b may form an edge part with a stepped height that changes upward, and a corner that bends upward may be formed. The opening 72b can suppress the generation of a relatively large surface tension of the cleaning water by forming an irregular opening with a corner or a groove that protrudes outward, compared to a circular opening.

[0057] The opening 72b is formed in a polygonal shape, for example, a square shape. The opening 72b may be formed in a polygonal shape, for example, a star shape, an octagon shape, a hexagon shape, or a triangle shape. The opening 72b has a plurality of corners, for example, three or more corners, so that the surface tension of the water at the opening can be more easily reduced. The square opening 72b of this embodiment is formed on the same horizontal plane. The corners of the cornered shape do not necessarily have to be sharp, and may be rounded, for example. In other words, the opening 72b has corners that reduce the interfacial tension between the cleaning water present on the expanded internal space side of the opening and the outside air.

[0058] As shown in FIG. 11 and FIG. 17, the fitting holes 78 of the valve body below float additional part 72 are provided in a plurality of positions, and each fitting hole 78 is provided around the opening 72b at a position facing each side of the opening 72b. The fitting holes 78 are provided at four positions facing each of the four sides of the rectangular opening 72b. The fitting holes 78 form a substantially rectangular hole when viewed from above, and the longitudinal side 78a is disposed substantially parallel to the opposing side of the opening 72b. Therefore, when flush water flows into the additional internal space 74 from the gap between the mounting part 76 and the fitting holes 78 as shown in FIG. 8, as shown in FIG. 17, the flush water can easily flow in a linear direction from the side 78a of the fitting holes 78 toward the opposing side of the opening 72b as shown by the arrow F11, and the flush water can easily flow out of the opening 72b.

[0059] The fitting holes 78 of the valve body below float additional portion 72 form two sets of two fitting holes 78 arranged at opposing positions across the opening 72b (i.e., formed by four openings 72b), and the opposing line A1 connecting the centers of the opposing fitting holes 78 of the first set intersects perpendicularly with the opposing line A2 connecting the centers of the opposing fitting holes 78 of the second set.

[0060] The valve body lower float additional part 72 forms an inclined surface 72c where at least a part of the outer periphery on the lower side is inclined inward. For example, the valve body lower float additional part 72 may form an inclined surface where at least a part of the outer periphery on the lower side is inclined inward. The valve body lower float additional part 72 is formed so that the diameter decreases downward in the region where the inclined surface 72c is formed, and the cross-sectional area of ​​the horizontal cross section in the region where the inclined surface 72c is formed decreases downward. In particular, the outer circumferential portion 72 e of the valve body lower float additional portion 72 that abuts against the lower surface 42 b of the valve body 42 is formed so as to taper inwardly from the lower surface 42 b of the valve body 42 toward the drain port 32 .

[0061] As a modified example, as shown in Fig. 13, the valve body lower float additional part 72 may have a curved surface in which at least a part of the outer periphery on the lower side is curved in an arc shape toward the inside. For example, in Fig. 13, the valve body lower float additional part 72 has a curved surface in which at least a part of the outer periphery on the lower side is curved in an arc shape toward the inside on both the left and right sides in the central cross section. The valve body lower float additional part 72 has a trumpet shape that opens upward in the central cross section. The curved surface is formed in an arc shape, and flush water can flow while changing direction gently along the curved surface.

[0062] In this embodiment, the bottom 72a (the top part protruding downward) of the valve body lower float additional part 72 extends in the left-right direction further below the lower end 48d of the outer cylinder 48b of the float structure 48. The valve body lower float additional part 72 is attached so that the upper surface 72f abuts against the lower surface 42b of the valve body 42, and in a state in which the upper surface 72f abuts against the lower surface 42b of the valve body 42, the internal vertical wall 72g of the valve body lower float additional part 72 extends vertically downward for a predetermined distance from the vicinity of the lower surface 42b, and is then connected to the bottom part 72a extending in the horizontal direction. Therefore, in a state in which the valve body lower float additional part 72 is attached to the lower surface 42b side of the valve body 42, the valve body lower float additional part 72 forms an additional internal space 74 whose sides and upper part are covered further below the reference position L of the height of the valve body 42 (the position where the initial valve body inner cap 71 is placed is illustrated as the reference position L). In this manner, the valve body below float additional portion 72 is provided below the lower surface 42b of the valve body 42, and the additional internal space 74 is also formed below the valve body 42. In the present invention, it was initially considered that the valve body 42 was formed as a single disk, and the valve body inner cap 71 formed on the inward side of the valve body 42 was formed as a flat plate on approximately the same plane as the valve body 42. For comparison with the present invention, such an original valve body inner cap 71 is shown by a dotted line in Fig. 8. The position where such an original valve body inner cap 71 is disposed is shown as the reference position L. In the present invention, the valve body below float additional portion 72 forms an additional internal space 74 that is covered on the side and the top further below the reference position L of the height of the valve body 42 .

[0063] The valve body lower float additional part 72 of the drain valve device 24 of the present invention is formed to be removable. The valve body lower float additional part 72 is formed to be attachable to the valve body 42, but the valve body lower float additional part 72 may be formed integrally with the valve body 42 from the beginning. When the valve body lower float additional part 72 is attachable as described above, it can be attached, for example, in place of the valve body inner cap 71 of the valve body 42 of the comparative example. Therefore, the drain valve device 24 that realizes the dead water level DWL2 can be formed by removing the valve body inner cap 71 from the valve body 42 and the drain valve device 24 to which the valve body inner cap 71 was originally attached and later attaching the valve body lower float additional part 72. Also, if the drain valve device 24 has a valve body 42 to which the valve body lower float additional part 72 can be attached, the drain valve device 24 of the present invention can be formed by later attaching the valve body lower float additional part 72.

[0064] Next, the operation of the drain valve device 24 will be described with reference to Figures 14 to 16. Figure 14 is a cross-sectional view showing the state of the drain valve device according to one embodiment of the present invention before drainage begins, Figure 15 is a cross-sectional view showing the state of the drain valve device according to one embodiment of the present invention in the middle of drainage, and Figure 16 is a cross-sectional view showing the state of the drain valve device according to one embodiment of the present invention just after the valve body closes the drain port and drainage has finished.

[0065] In the drain valve device 24, a low DWL setting causes a larger amount of flush water to be drained from the drain outlet 32 ​​than a high DWL setting. Conversely, a high DWL setting causes a smaller amount of flush water to be drained from the drain outlet 32 ​​than a low DWL setting.

[0066] 14 shows the state before flush water drainage begins. In the drain valve devices 24 with the low DWL setting and the high DWL setting, the drain port 32 is closed by the valve body 42. At this time, the water levels in the water storage tank 18 are both at the full water level WL0. Air is stored in the internal space 49 and the additional internal space 74, and the float structure 48 and the valve body below float additional part 72 are subjected to buoyancy.

[0067] Thereafter, when the lever handle 26 is operated, the spindle 28 rotates (see FIG. 2). As shown in FIG. 15, when the spindle 28 rotates, the valve body 42 is pulled up by the ball chain 30 and moves to the uppermost position of the movable range. This causes flush water to be drained from the drain port 32.

[0068] The difference in operation between the drain valve device 24 with a high DWL setting and the drain valve device 24 with a low DWL setting will be briefly described below. In the drain valve device 24 with a high DWL setting, when flush water is drained and the water level in the water storage tank 18 reaches a predetermined water level WL1, the balance between the buoyancy and the weight of the float structure 48 and the float extension 72 below the valve body is lost, and the valve body 42 and the float structure 48 begin to descend in conjunction with the subsequent drop in the water level. On the other hand, in the drain valve device 24 with a low DWL setting, when the water level in the water storage tank 18 is at the predetermined water level WL1, the buoyancy of the float structure 48 is sufficiently acting against its own weight, so that the valve body 42 remains stagnant in the uppermost position.

[0069] Subsequently, in the drain valve device 24 with the high DWL setting, the valve body 42 continues to descend in conjunction with the falling water level. On the other hand, in the drain valve device 24 with the low DWL setting, when the water level in the water storage tank 18 reaches the water level WL2 of the predetermined height, the balance between the buoyancy and the weight of the float structure 48 and the float extension 72 below the valve body is lost, and the valve body 42 and the float structure 48 start to descend in conjunction with the subsequent drop in the water level. In other words, in the drain valve device 24 with the low DWL setting, the valve body 42 starts to descend later than in the drain valve device 24 with the high DWL setting.

[0070] Furthermore, even if the valve body 42 continues to descend, the flush water flows out from the opening 68 of the guide portion 64, so that the flush water does not accumulate within the guide portion 64, and no weight exceeding the flush water stored in the water storage portion 52 is added to the float structure 48.

[0071] Next, in the drain valve device 24 with the high DWL setting, the valve element 42 reaches the lowest position of its movable range and abuts against the valve seat 43, blocking the drain outlet 32. When the valve element 42 approaches the lowest position in conjunction with the lowering water level, it is attracted by the flow of flush water drained from the drain outlet 32 ​​and rapidly descends to the lowest position. Here, as shown in Figure 16, in the drain valve device 24 with the high DWL setting, the water level when the drain outlet 32 ​​is blocked by the valve element 42 is the dead water level DWL1. On the other hand, in the drain valve device 24 with the low DWL setting, the valve body 42 continues to descend in conjunction with the descending water level.

[0072] Next, as shown in Figure 16, the valve body 42 in the drain valve device 24 with a low DWL setting reaches the lowest position of its movable range later than the drain valve device 24 with a high DWL setting, and closes the drain outlet 32. Here, in the drain valve device 24 with a low DWL setting, the water level when the drain outlet 32 ​​is closed by the valve body 42 is the dead water level DWL2, which is lower than the dead water level DWL1 in the drain valve device 24 with a high DWL setting. Meanwhile, because the full water level WL0 (see Figure 14) is the same in all drain valve devices 24 with different settings, the drain valve device 24 with a low DWL setting drains more flush water from the drain outlet 32 ​​than the drain valve device 24 with a high DWL setting.

[0073] Next, the operation of the drain valve device 24 will be described by providing the drain valve device 24 with the float additional portion 72 below the valve body. The float additional portion 72 below the valve body can be provided in both the drain valve device 24 with a high DWL setting and the drain valve device 24 with a low DWL setting. Since the float additional portion 72 below the valve body is particularly effective in lowering the dead water level in the drain valve device 24 with a low DWL setting, the characteristic operation of the drain valve device 24 with a low DWL setting will be described, and the operation of the drain valve device 24 with a high DWL setting will be omitted.

[0074] As shown in FIG. 15, when the valve body 42 is pulled up from the drain port 32, flush water is drained. During drainage, as shown by arrow F1, flush water flows from around the drain valve device 24 in the water storage tank 18 toward the lower side of the valve body 42 and the drain port 32. At this time, the valve body lower float additional part 72 forms an inclined surface 72c in which at least a part of the lower outer periphery 72e is inclined inward, so that flush water can flow smoothly along the inclined surface 72c without being easily hindered, as shown by arrow F2. By forming the inclined surface 72c on the lower outer periphery 72e of the valve body lower float additional part 72, with which flush water flowing below the valve body 42 is likely to collide, it is possible to prevent the flow of flush water as shown by arrow F2 from colliding with the valve body lower float additional part 72 or from becoming turbulent. Air is stored in the internal space 49 and the additional internal space 74, and the float structure 48 and the valve body below float additional portion 72 are subjected to buoyancy.

[0075] In the present invention, a float additional portion 72 below the valve body is provided so as to protrude further toward the underside 42b of the valve body 42. The provision of the float additional portion 72 below the valve body is effective in lowering the dead water level, but on the other hand, it is provided so as to protrude below the valve body 42, narrowing the flow path area below the valve body 42, and a part of the float additional portion 72 below the valve body is likely to collide with the flow of flush water flowing toward below the valve body 42, resulting in a problem of a decrease in the instantaneous flow rate of flush water being drained.

[0076] If no inclined surface is formed on the outer periphery 72e below the valve body below float additional portion 72, causing an outer periphery corner to exist, as shown by arrow F1, part of the flush water flowing downward from the valve body 42 will collide with the outer periphery 72e below the valve body below float additional portion 72, and this turbulence will impede the subsequent flow, causing a problem of a decrease in the instantaneous flow rate of flush water flowing from around the drain valve device 24 toward the drain outlet 32. If the instantaneous flow rate of flush water supplied from the storage tank 18 to the toilet body 2 decreases, in a wash-down toilet, the flushing ability of the toilet body 2 will decrease, and in a siphon toilet, the siphon action will be delayed, causing a decrease in flushing ability.

[0077] In the present invention, in order to solve the problems described above, even when a valve body below float extension 72 is provided so as to protrude further toward the underside 42b of the valve body 42, an inclined surface 72c is formed on the outer periphery 72e on the lower side of the valve body below float extension 72, and a smooth flow of flushing water is formed as shown by arrow F2, so that a decrease in the instantaneous flow rate of flushing water supplied from the water storage tank 18 to the toilet body 2 during flushing is suppressed, and a relatively high instantaneous flow rate can be achieved.

[0078] Furthermore, even if the flush water gradually decreases during drainage, the valve body below float additional section 72 provided on the underside of the valve body 42 is in a state where flush water is present around it and the additional internal space 74 inside is filled with air, so that it generates buoyancy upward. In other words, by providing the valve body below float additional section 72 on the underside of the valve body 42, the valve body below float additional section 72 can be reliably positioned below the flush water level, the buoyancy of the valve body below float additional section 72 can be added to the buoyancy of the float structure 48, and the timing at which the valve body 42 starts to descend can be reliably delayed. Therefore, since the timing at which the valve body 42 starts to descend is delayed, flush water can be drained down to the lower dead water level DWL2, and the amount of flush water for one flush of the toilet body 2 can be increased without significantly changing the configuration of the water storage tank 18 and the drain valve device 24, while the drain valve device 24 is formed compactly.

[0079] The valve body below float additional part 72 is attached by fitting the attachment part 76 and the fitting hole 78, and flush water can flow into the additional internal space 74 from the gap between the attachment part 76 and the fitting hole 78. Therefore, when the valve body 42 is pulled up from the drain port 32 and flush water is drained, flush water may flow into the additional internal space 74 from the fitting hole 78. Flush water may also flow into the additional internal space 74 from the opening 72b. The opening 72b is formed so that flush water that has flowed into the additional internal space 74 can be easily discharged from the additional internal space 74 during drainage from the drain port 32 of the water storage tank 18. The center of the opening 72b is located at the center of the bottom of the valve body below float additional part 72. The flush water that has flowed into the additional internal space 74 flows down toward the opening 72b at the bottom of the valve body below float additional section 72, and tries to flow out from the inside side of the opening 72b (the inside side of the valve body below float additional section 72) toward the outside side (the outside side of the valve body below float additional section 72). Here, by forming the opening 72b in an angular shape (for example, a square shape), it is possible to easily reduce the surface tension of the flush water that remains on the inside edge of the opening 72b, and the discharge performance of the flush water from the valve body below float additional section 72 can be improved. By reducing the surface tension of the flush water that tries to remain on the inside edge of the opening 72b, it becomes difficult to maintain the state in which an interface is formed between the flush water and the air on the edge, and the flush water is more likely to flow out from the edge of the opening 72b to the outside. Therefore, during drainage from the water storage tank 18, flushing water can be easily discharged from the added internal space 74, and the valve body below float additional section 72 generates a buoyancy of the amount originally planned based on the size of the added internal space 74, allowing it to operate as expected. The structure of the opening 72b can prevent the occurrence of a phenomenon in which the flush water present on the inner side of the opening 72b tends to remain on the inner side of the opening 72b due to surface tension. In addition, the flush water remains in the expanded internal space 74, which reduces the buoyancy generated by the expanded internal space 74, and prevents the valve body from closing at a timing earlier than the expected valve closing timing. Therefore, it is possible to prevent the amount of flush water supplied from varying and the reliability of the flushing performance of the drain valve device 24 from decreasing due to the valve body being closed at different timings for each flush.

[0080] 17 and other drawings, the fitting holes 78 are provided at four locations that face the four sides of the rectangular opening 72b. Therefore, when flushing water flows into the expanded internal space 74 from the fitting holes 78, it can easily flow in a linear direction from a side 78a of the fitting holes 78 toward the opposing side of the opening 72b, as shown in Fig. 17, so that flushing water can easily flow out to the outside from the opening 72b in a relatively short time. In addition, the opposing line A1 connecting the first set of opposing fitting holes 78 perpendicularly intersects with the opposing line A2 connecting the second set of opposing fitting holes 78, so flush water flowing in from each fitting hole 78 can easily enter the opening 72b after colliding with flush water flowing in from a fitting hole 78 at an opposing position across the opening 72b. Therefore, the performance of discharging flush water from the valve body below float additional part 72 can be further improved.

[0081] As the flush water drops, the balance between the buoyancy and the weight of the float structure 48 and the valve body below float additional section 72 is lost, and the valve body 42 and float structure 48 drop in conjunction with the subsequent drop in the water level, and the valve body 42 abuts against the valve seat 43, blocking the drain port 32. At this time, flush water has been stored up to the dead water level DWL2 in the water storage tank 18. Air is stored in the internal space 49 and the additional internal space 74, and the float structure 48 and the valve body below float additional section 72 are receiving buoyancy. Thereafter, the water supply device 22 supplies flush water, and the flush water is raised to the full water level WL0, and the flush operation ends.

[0082] With regard to the dead water level of flush water, in the case where the original valve disc inner cap 71 is formed on the valve disc 42 without the valve disc below float additional part 72 being provided as a comparative example (the original valve disc inner cap 71 is shown in FIG. 16), the valve disc below float additional part 72 is not provided, and the timing at which the valve disc 42 starts to descend is determined solely by the buoyancy generated in the float structure 48, so the timing at which the valve disc 42 starts to descend is advanced, and flush water can only be drained up to the dead water level DWL3 (shown by a dotted line) which is higher than the dead water level DWL2. Initially, it was thought that it would be difficult to achieve this low dead water level DWL3 with such a low DWL setting to an even lower dead water level DWL2 without significant design changes to the water storage tank 18 and the drain valve device 24. The present invention solves these problems and, with the above-mentioned configuration, makes it possible to lower the low dead water level DWL3 of the low DWL setting to an even lower dead water level DWL2. Furthermore, when setting the dead water level DWL2 even lower, a new problem (the problem of a decrease in instantaneous flow rate) is solved.

[0083] As described above, according to the drain valve device 24 of this embodiment, even if flush water flows into the additional internal space 74 from the fitting hole 78 or the opening 72b, the angular shape of the opening 72b makes it easier to reduce the surface tension of the flush water in contact with the opening 72b, improving the flush water discharge performance from the valve body below float additional part 72. As a result, the water in contact with the opening 72b in the valve body below float additional part 72 remains inside the opening due to surface tension and does not flow out, the buoyancy generated by the additional internal space 74 is reduced, and the valve body 42 is prevented from closing at a timing earlier than the expected valve closing timing. Therefore, it is possible to provide a drain valve device 24 that can increase the flow rate of flush water drained from the full water level to the dead water level during the drainage operation of the water storage tank device 4 and improves the reliability of the flush water supply capacity to the toilet body 2, without changing the size of the drain valve device 24 or the size of the water storage tank 18. Also, the surface tension of the flush water in contact with the opening 72b can be easily reduced, improving the discharge performance of the flush water from the valve body below float additional section 72. This allows the size of the opening 72b to be made smaller, making it difficult for flush water to enter the valve body below float additional section 72 from the opening 72b. Therefore, the buoyancy generated by the additional internal space 74 is reduced, making it possible to more effectively prevent the valve body 42 from closing earlier than the expected valve closing timing.

[0084] Furthermore, according to the drain valve device 24 of this embodiment, the opening 72b is formed in a polygonal shape, so that the surface tension of the flush water in contact with the opening 72b can be more easily reduced by the multiple, for example, three or more corners, and the flush water discharge performance from the inside of the valve body below float additional part 72 can be further improved. As a result, flush water in contact with the opening 72b in the valve body below float additional part 72 remains inside the opening 72b due to surface tension and does not flow out, the buoyancy generated by the additional internal space 74 is reduced, and the valve body 42 can be more effectively prevented from closing at a timing earlier than the expected valve closing timing. Therefore, it is possible to provide a drain valve device 24 that can increase the flow rate of flush water discharged from the full water level to the dead water level in the drainage operation of the water storage tank device 4 and further improve the reliability of the flush water supply capacity, without changing the size of the drain valve device 24 or the size of the water storage tank 18.

[0085] Furthermore, according to the drain valve device 24 of this embodiment, flushing water that flows into the expanded internal space 74 from the fitting hole 78 can be made to flow out from each side of the opposing opening 72b more easily, thereby improving the discharge performance of flushing water from the valve body below float expansion section 72.

[0086] Furthermore, according to the drain valve device 24 of this embodiment, the opposing line connecting the first set of opposing fitting holes 78 perpendicularly intersects with the opposing line connecting the second set of opposing fitting holes 78, so flush water flowing in from each fitting hole 78 can easily enter the opening 72b after colliding with flush water flowing in from a fitting hole 78 at a position opposing the opening 72b. Therefore, the performance of discharging flush water from the valve body below float additional part 72 can be further improved.

[0087] Furthermore, according to the drain valve device 24 of this embodiment, the opening 72b can be formed relatively easily using four straight lines, which makes it possible to improve the productivity of the valve body below float additional portion 72 and reduce the manufacturing cost.

[0088] According to one embodiment of the present invention configured in this manner, the water storage tank device 4 is equipped with a drain valve device 24 and a water storage tank 18, and a water storage tank device 4 can be provided that can increase the flow rate of flush water drained from the full water level to the dead water level during the drainage operation of the water storage tank device 4 without changing the size of the drain valve device 24 or the size of the water storage tank 18, and that further improves the reliability of the flush water supply capacity.

[0089] According to one embodiment of the present invention configured in this manner, the flush toilet 1 is equipped with the above-mentioned water storage tank device 4, and without changing the size of the drain valve device 24 or the size of the water storage tank 18, it is possible to increase the flow rate of flush water drained from the full water level to the dead water level during the drainage operation of the water storage tank device 4, and it is possible to provide a flush toilet 1 with more reliable flushing performance. [Explanation of symbols]

[0090] 1: Flush toilet 4: Water tank device 18: Water tank 24: Drain valve device 32:Drain port 42: Valve body 44d:Aperture 48: Float structure 49: Interior space 68 :Aperture 72: Additional float installed below valve body 72b: Opening 74: Additional internal space 76: Mounting part 78: Fitting hole 78a: Side A1: Oncoming line A2: Oncoming line

Claims

1. A drain valve device that is attached to a water storage tank that stores flush water, a valve body provided above a drain outlet provided on a bottom surface of the water storage tank and movable in a vertical direction to open and close the drain outlet; a float structure attached to the valve body and lowering the valve body in conjunction with a drop in the water level in the water storage tank by a buoyancy generated in an internal space; A valve body lower float additional portion is provided so as to protrude inwardly of the valve body and downwardly from the valve body, thereby forming an additional internal space, The valve body below float additional portion is formed with a fitting hole that fits with the mounting portion of the float structure, and the fitting hole communicates with the additional internal space in the valve body below float additional portion, and further, the valve body below float additional portion is formed with an opening for allowing flush water that has flowed into the additional internal space to flow out, A drain valve device characterized in that the opening of the float attachment portion below the valve body is formed in a polygonal shape.

2. 2. The drain valve device according to claim 1, wherein the fitting holes of the valve body lower float additional portion are provided in a plurality of positions around the opening so as to face each side of the opening.

3. The drain valve device according to claim 2, wherein the fitting holes of the valve body lower float additional portion form two sets arranged at opposing positions across the opening, and an opposing line connecting the opposing fitting holes of the first set intersects perpendicularly with an opposing line connecting the opposing fitting holes of the second set.

4. 4. The drain valve device according to claim 2, wherein the opening of the float attachment portion below the valve body is formed in a rectangular shape.

5. A drain valve device according to any one of claims 1 to 4; A water storage tank device comprising the above water storage tank for storing flush water.

6. A flush toilet equipped with the water storage tank device according to claim 5.

Images