Flush water tank device and flush toilet device equipped with same

Abstract

To provide a flush water tank device capable of maintaining a sufficiently high initial instantaneous flow rate of flush water discharged when flushing a toilet bowl, while providing an overflow pipe to a drain valve. [Solution] The present invention is a flush water tank device (4) that stores flush water for flushing a toilet, and is characterized by having a flush water tank body (26) that stores flush water for flushing the toilet, an overhead drain valve (27) that opens and closes a drain outlet provided in the flush water tank body, an overflow pipe section (28) that is provided in the drain valve and discharges flush water from the flush water tank body when the water level in the flush water tank body rises above a predetermined water level, and a movable shielding plate (29) that is provided below the overflow pipe section and that prevents some of the flush water that flows into the drain outlet from entering the overflow pipe section from the lower end when the drain valve is opened.

Description

[Technical Field]

[0001] The present invention relates to a flush water tank apparatus, and more particularly to a flush water tank apparatus that stores flush water for flushing a toilet, and a flush toilet apparatus that is equipped with the same. [Background technology]

[0002] JP 2016-33300 A (Patent Document 1) describes a drain valve drive unit. The drain valve driven by this drain valve drive unit is of the direct-top type, and is pulled directly up from the drain outlet of the water storage tank, opening the drain outlet. An overflow pipe is provided in the center of this drain valve, and the overflow pipe is pulled up along with the drain valve when the drain outlet opens. When the water level in the water storage tank is higher than the upper end of the overflow pipe with the drain outlet closed, flush water in the water storage tank flows into the overflow pipe and is discharged into the flush toilet. This prevents water from leaking from the water storage tank.

[0003] By adopting a drain valve with an integrated overflow pipe, such as the drain valve drive unit described in Patent Document 1, it is possible to arrange the drain valve and overflow pipe compactly within the water storage tank. Furthermore, with a drain valve with an integrated overflow pipe, when the drain valve is opened, air that has accumulated in the flow path downstream of the drain valve can be discharged through the overflow pipe. As a result, it is possible to prevent air from mixing with the flush water discharged from the drain outlet, and to prevent abnormal noise from occurring when the toilet is flushed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-33300 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the drain valve drive unit described in Patent Document 1, when the drain valve is open, a problem occurs in that some of the flush water flowing out of the storage tank to the drain outlet temporarily escapes into the overflow pipe and is not quickly discharged from the drain outlet.As a result, the initial instantaneous flow rate of flush water discharged from the flush water tank device when it is discharged from the flush toilet's spout decreases, resulting in a problem of reduced toilet flushing performance.

[0006] Therefore, the object of the present invention is to provide a flush water tank device that can maintain a sufficiently high initial instantaneous flow rate of flush water discharged during toilet flushing while providing an overflow pipe to the drain valve, and a flush toilet device equipped with the same. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention is a flush water tank device that stores flush water for flushing a toilet, and is characterized by having: a flush water tank body that stores flush water for flushing a toilet; a direct-top drain valve that opens and closes a drain outlet provided in the flush water tank body; an overflow pipe section that is provided in the drain valve and discharges flush water from within the flush water tank body when the water level in the flush water tank body rises above a predetermined water level; and a movable shield plate that is provided below the overflow pipe section and that prevents some of the flush water that flows into the drain outlet from entering the overflow pipe section from the lower end when the drain valve is opened.

[0008] According to the present invention configured in this manner, a shielding plate is provided at the bottom of the overflow pipe, so when the drain valve is opened, it is possible to prevent some of the flush water flowing into the drain outlet from entering the overflow pipe from the bottom end. As a result, it is possible to increase the initial instantaneous flow rate of flush water discharged when the toilet is flushed. Furthermore, because the shielding plate is movable, it can be moved to different positions when the drain valve is opened and when overflow occurs in the flush water tank body. As a result, it is possible to fully prevent flush water from entering from the bottom end of the overflow pipe when the drain valve is opened, while still fully ensuring the function of the overflow pipe that allows flush water to flow out.

[0009] In the present invention, the shielding plate is preferably configured so that its outer diameter is larger than the smallest inner diameter of the overflow pipe portion.

[0010] According to the present invention configured in this manner, the outer diameter of the shielding plate is larger than the smallest inner diameter of the overflow pipe section, so that the shielding plate can effectively prevent cleaning water from entering the overflow pipe section.

[0011] In the present invention, the shielding plate is preferably supported by being suspended at its approximate center, and is attached so as to be rotatable about the support point of the shielding plate.

[0012] According to the present invention configured in this way, the shielding plate is supported by suspending it approximately at its center and is attached so that it can rotate around its support point. As a result, the shielding plate can tilt in any direction when overflow occurs from the flush water tank body, allowing the flush water that flows in from the upper end of the overflow pipe to flow out into the flush toilet body without being excessively blocked.

[0013] In the present invention, a movement restricting portion for restricting the movement range of the shielding plate is preferably provided at the lower portion of the overflow pipe portion.

[0014] According to the present invention configured in this manner, a movable regulating section that regulates the range of movement of the shielding plate is provided at the bottom of the overflow pipe section, so that the range of movement of the shielding plate can be regulated to an appropriate range, making it possible to both prevent cleaning water from entering from below the shielding plate and discharge cleaning water that has flowed in from the upper end of the overflow pipe section.

[0015] In the present invention, the shielding plate is preferably made of a material having a density lower than that of water.

[0016] According to the present invention configured in this manner, the shielding plate is made of a material that has a lower density than water, so when the drain valve is opened, the shielding plate is lifted up by the cleaning water flowing below, effectively preventing the cleaning water from entering the overflow pipe section.

[0017] In the present invention, preferably, the device further comprises a ball chain for pulling up the drain valve when the drain valve is opened, and the shielding plate is suspended by the ball chain.

[0018] According to the present invention configured in this manner, the shielding plate is suspended by a ball chain, so that the shielding plate can be movably supported in an appropriate position without the need for a special structure to support the shielding plate.

[0019] The present invention is also a flush toilet apparatus equipped with a flush water tank apparatus, characterized by having a flush toilet main body and a flush water tank apparatus of the present invention attached to the rear of the flush toilet main body, for storing flush water used to clean the flush toilet main body. [Effects of the Invention]

[0020] With the flush water tank apparatus and flush toilet apparatus equipped with it of the present invention, the initial instantaneous flow rate of flush water discharged during toilet flushing can be maintained sufficiently high, even while an overflow pipe portion is provided in the drain valve. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a plan view showing a flush toilet apparatus according to an embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a side cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 2 is an enlarged cross-sectional view showing the connection between the flush toilet main body and flush water tank main body in a flush toilet apparatus according to an embodiment of the present invention. [Figure 4] 2 is a cross-sectional view showing an enlarged view of the drain outlet portion of the flush water tank body provided in the flush water tank apparatus according to an embodiment of the present invention. FIG. [Figure 5] FIG. 2 is a perspective view showing a drain valve provided in a flush water tank apparatus according to an embodiment of the present invention. [Figure 6] 2 is an enlarged perspective view showing the lower end of a drain valve provided in a flush water tank apparatus according to an embodiment of the present invention. FIG. [Figure 7] 2 is an enlarged cross-sectional view showing the lower end of a drain valve provided in a flush water tank apparatus according to an embodiment of the present invention. FIG. [Figure 8] 1 is a cross-sectional view showing the flow of flush water within the flush water tank body and near the drain outlet when the drain valve is opened in a flush water tank apparatus according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0022] Next, a flush water tank apparatus according to an embodiment of the present invention, and a flush toilet apparatus equipped with the same, will be described with reference to the accompanying drawings. Fig. 1 is a plan view showing a flush toilet apparatus according to an embodiment of the present invention, and Fig. 2 is a side cross-sectional view taken along line II-II in Fig. 1.

[0023] As shown in Figures 1 and 2, the flush toilet device 1 according to an embodiment of the present invention is a siphon jet type flush toilet, and comprises a ceramic flush toilet body 2, a resin toilet seat and lid (not shown) placed on the top surface of this flush toilet body 2, and a flush water tank device 4 placed at the upper rear of the flush toilet body 2 and covered by a resin cover (not shown).

[0024] The flush toilet body 2 is formed with a bowl portion 6 for receiving waste, a drain trap pipe 8 provided at the bottom of the bowl portion 6 for discharging waste by siphon action, a rim spout 10 for rim water spouting, a rim water conduit 12 for guiding flush water to the rim spout, a jet spout 14 for jet water spouting, and a jet water conduit 16 for guiding flush water to the jet spout 14.

[0025] Bowl portion 6 has a bowl-shaped waste receiving surface 18, a rim portion 20 formed along the upper edge of bowl portion 6, and a shelf portion 21 formed between waste receiving surface 18 and rim portion 20. Bowl portion 6 also has a pot portion 22 formed in the area below waste receiving surface 18 and connected to drain trap pipe line 8. A water sealing surface W is formed inside pot portion 22.

[0026] The drain trap pipeline 8 has an inlet portion 8a, an ascending pipeline 8b extending upward from the inlet portion 8a, a descending pipeline 8c extending downward from the ascending pipeline 8b, and a top portion 8d located between the descending pipeline 8c and the ascending pipeline 8b and defining the seal water level. Here, the lower end of the descending pipe 8c of the drain trap pipe 8 is connected to a drain pipe (not shown) via a drain socket (not shown).

[0027] When looking at the flush toilet body 2 from the front, the rim spout 10 is formed on the rear left side of the rim portion 20. The rim spout 10 spouts flush water forward, and this flush water swirls around the inner circumferential surface of the rim portion 20 and the shelf surface of the shelf portion 21 as it flows down to the waste receiving surface 18.

[0028] The rim water conduit 12 is formed in a tapered shape with the flow path cross section gradually becoming smaller towards the rim water outlet 10. Flush water is supplied to the rim water conduit 12 from the water mains via the flush water tank device 4, and flush water is discharged from the rim water outlet 10 due to the water supply pressure of the water mains.

[0029] Jet water outlet 14 is formed in the bottom of bowl portion 6. Jet water outlet 14 is positioned opposite inlet 8a of drain trap pipe 8 and is directed toward inlet 8a of drain trap pipe 8. Jet water outlet 14 ejects flush water toward inlet 8a of drain trap pipe 8, and this flush water flows into drain trap pipe 8, activating the siphon action.

[0030] The jet water conduit 16 comprises an upstream flow path 16a that extends forward from the flush water tank apparatus 4, a bent flow path 16b that bends from this upstream flow path, and a downstream flow path 16c that extends rearward from this bent flow path and connects to the jet spout 14. Flush water is supplied to the jet water conduit 16 from the flush water tank body 26 of the flush water tank apparatus 4, and flush water is spouted from the jet spout 14 due to the head pressure of the flush water. Thus, in this embodiment, flush water discharged from the rim spout 10 is supplied directly from the water main, and flush water discharged from the jet spout 14 is supplied from the flush water tank body 26 (Figure 1). However, as a modified example, the present invention can also be applied to a flush toilet apparatus in which the entire amount of flush water discharged is supplied from the flush water tank.

[0031] Next, with new reference to FIGS. 3 to 7, the configuration of the flush water tank apparatus 4 according to an embodiment of the present invention will be described. Figure 3 is an enlarged cross-sectional view showing the connection between the flush toilet main body 2 and flush water tank main body 26 in the flush toilet apparatus 1 of this embodiment. Figure 4 is an enlarged cross-sectional view showing the drain port portion of the flush water tank main body 26 provided in the flush water tank apparatus 4.

[0032] As shown in Figures 1 and 2, the flush water tank device 4 has a valve unit 24 that starts and stops the supply of flush water from the water line, a flush water tank body 26 made of resin that stores the flush water supplied via the valve unit 24, and a drain valve 27 that drains and stops the flush water from the flush water tank body 26.

[0033] The valve unit 24 has a tank water supply solenoid valve 24a, a rim water discharge solenoid valve 24b, etc., and is configured to control the supply and stop of tap water supplied from the water supply system into the flush water tank main body 26, and the discharge and stop of tap water from the rim water discharge port 10.

[0034] As shown in Figure 3, the flush water tank main body 26 is configured to store flush water for flushing the flush toilet main body, and is fixed to the flush toilet main body 2 via a base plate 30. Also, a drain valve 27 and a drain valve drive mechanism 32 are arranged inside the flush water tank main body 26. When the drain valve 27 is lifted by the drain valve drive mechanism 32, the drain valve 27 opens and flush water is discharged from the flush water tank main body 26. In other words, the drain valve 27 is a direct-top drain valve that opens and closes a drain outlet provided in the flush water tank main body 26. Also, the flush water discharged from the flush water tank main body 26 flows through an inlet 2a provided on the upper rear surface of the flush toilet main body 2, and into the jet water conduit 16 provided inside the flush toilet main body 2. In other words, in this embodiment, the jet water conduit 16 forms a water passage that extends from the inlet 2a of the flush toilet main body 2.

[0035] In this embodiment, the flush water tank body 26 is a small resin tank with a volume of approximately 2 liters. As shown in Figure 2, the lower part of the flush water tank body 26 is positioned below the upper surface of the rim part 20 of the flush toilet body 2, and above the top 8d of the drain trap pipe 8. This makes the flush toilet apparatus 1 a low-silhouette type toilet. Also, in this embodiment, the flush water in the flush water tank body 26 is discharged from the jet spout 14 by gravity.

[0036] As shown in FIG. 3, the bottom surface of flush water tank body 26 is provided with an annular protrusion 26a that protrudes downward, and the inside of this annular protrusion 26a constitutes drain passage 26b, which is formed to extend downward from the bottom surface of flush water tank body 26. Furthermore, a groove 26c is formed on the outer circumferential surface of protrusion 26a, and an annular O-ring 34 is fitted into this groove 26c. Meanwhile, a circular drain opening 30a is provided in base plate 30, which supports flush water tank body 26. The circular opening at the lower end of drain passage 26b is formed with approximately the same diameter as drain opening 30a provided in base plate 30, and drain passage 26b and drain opening 30a are smoothly connected. In this embodiment, the lower end of drain opening 30a functions as drain outlet 30e for flush water tank device 4. The drain outlet may be formed integrally with the flush water tank body.

[0037] A cylindrical portion 30b protruding downward is provided on the bottom surface of the base plate 30 so as to surround the drain opening 30a. An annular upper surface recess 30c is formed on the upper surface of the bottom surface of the base plate 30 so as to surround the drain opening 30a. Meanwhile, an annular lower surface recess 30d is formed on the lower surface of the bottom surface of the base plate 30 so as to surround the cylindrical portion 30b.

[0038] Furthermore, protrusion 26a protruding from the bottom surface of flush water tank body 26 is received in upper surface recess 30c formed in the upper surface of base plate 30. In this way, by fitting protrusion 26a of flush water tank body 26 into upper surface recess 30c of base plate 30, O-ring 34 arranged on the outer periphery of protrusion 26a is crushed in the radial direction of drain passage 26b, and the gap between flush water tank body 26 and base plate 30 is sealed.

[0039] Meanwhile, a gasket 36 is placed inside a circular lower surface recess 30d formed on the underside of the base plate 30. The gasket 36 is configured in an overall circular shape, and is fitted around a cylindrical portion 30b formed on the inner periphery of the lower surface recess 30d, and is received inside the lower surface recess 30d. The base plate 30 is fixed to the upper rear surface of the flush toilet body 2 with multiple bolts 38 (only one is shown in Figure 3).

[0040] As a result, the packing 36, which is located in the underside recess 30d on the underside of the base plate 30, is compressed between the base plate 30 and the flush toilet main body 2. In other words, when the flush water tank main body 26 is fixed to the flush toilet main body 2 via the base plate 30, the packing 36 is sandwiched and crushed between the underside recess 30d of the base plate 30 and the periphery of the inlet 2a on the top surface of the flush toilet main body 2. This ensures watertightness between the base plate 30 and the flush toilet main body 2.

[0041] Next, as shown in Figure 4, drain passage 26b is a passage formed to extend downward from the bottom surface of flush water tank body 26, and has a circular cross section, configured so that the flow path cross-sectional area narrows downward. Also, the inner wall surface of drain passage 26b is curved in a convex shape facing upward in the vertical cross section shown in Figure 4. Furthermore, an annular seat surface 26d is provided at the inlet portion at the upper end of drain passage 26b so as to surround it. Seat surface 26d is a narrow, annular surface, and drain valve 27 seats on this seat surface 26d, and by lifting it from its seat, the drain outlet of flush water tank body 26 is opened and closed, and flush water is discharged or stopped.

[0042] That is, when flushing the bowl portion 6 of the flush toilet main body 2, the drain valve 27 is lifted by the drain valve drive mechanism 32 (Fig. 3) from the closed valve position P1 shown by the dashed line in Fig. 4 to the open valve position P2 shown by the chain line. When the drain valve 27 is in the closed valve position P1 and seated on the seat surface 26d, the discharge of flush water from the flush water tank main body 26 is stopped. Then, when the drain valve 27 is moved to the open valve position P2 and lifted off the seat surface 26d, flush water is discharged from the flush water tank main body 26.

[0043] Furthermore, as shown in Figure 4, a flow guide section 40 is provided at the bottom of flush water tank body 26 so as to surround the periphery of seat surface 26d. This flow guide section 40 is a surrounding wall surface that is provided to rise vertically outside seat surface 26d so as to surround seat surface 26d, and is formed concentrically with the circular seat surface 26d.

[0044] Furthermore, in this embodiment, the surrounding wall surface constituting the flow guide portion 40 is cut out at four locations on the circumference (only two are shown in FIG. 2). That is, the flow guide portion 40 has cutout portions 40a provided at equal intervals at four locations on the circumference, and the height of the surrounding wall surface is reduced in those portions.

[0045] Next, the structure of the drain valve 27 will be described with reference to FIGS. Figure 5 is a perspective view showing drain valve 27 provided in flush water tank apparatus 4 according to an embodiment of the present invention. Figure 6 is a perspective view showing an enlarged view of the lower end of drain valve 27. Figure 7 is a cross-sectional view showing an enlarged view of the lower end of drain valve 27.

[0046] As shown in Fig. 5, drain valve 27 has disk portion 27a seated on seat surface 26d and overflow pipe portion 28 extending perpendicular to disk portion 27a. Overflow pipe portion 28 is composed of first pipe portion 28a extending vertically upward from the upper surface of disk portion 27a and second pipe portion 28b extending vertically downward from the lower surface of disk portion 27a. Drain valve 27 also has a ball chain 31 extending vertically upward from the center of disk portion 27a through overflow pipe portion 28 (Fig. 3).

[0047] Disk portion 27a is a member formed in the shape of a circular flat plate with an outer diameter larger than seat surface 26d, and is configured to stop the discharge of flush water from within flush water tank body 26 by sitting on seat surface 26d. Furthermore, a circular opening 27b (Fig. 7) is provided in the center of disk portion 27a.

[0048] Overflow pipe section 28 is made up of first pipe section 28a and second pipe section 28b, which are arranged concentrically. First pipe section 28a is a cylindrical pipe that extends vertically upward from the top surface of disc section 27a, concentrically with disc section 27a, and its upper end extends above the surface of the flush water stored in flush water tank body 26 when the flush toilet device 1 is in standby state (Figure 3).

[0049] On the other hand, second pipe portion 28b is a cylindrical pipe that extends vertically downward from the underside of disk portion 27a concentrically with disk portion 27a, and its lower end is open. Second pipe portion 28b extends so as to protrude downward from seat surface 26d when drain valve 27 is seated on seat surface 26d. Furthermore, the inner diameter of second pipe portion 28b is configured to be larger than the inner diameter of first pipe portion 28a.

[0050] Furthermore, first pipe portion 28a provided on the upper side of disk portion 27a and second pipe portion 28b provided on the lower side of disk portion 27a each surround opening 27b of disk portion 27a. Therefore, first pipe portion 28a provided on the upper side of disk portion 27a is in communication with second pipe portion 28b provided on the lower side of disk portion 27a via opening 27b. In other words, first pipe portion 28a provided on the upper side of disk portion 27a and second pipe portion 28b provided on the lower side of disk portion 27a communicate with the space above and the space below disk portion 27a.

[0051] Furthermore, as will be described later, when the flush toilet apparatus 1 is in its standby state, an air layer exists below the disc portion 27a, and the lower end of the second pipe portion 28b extends into this air layer. Therefore, the air layer below the seat surface 26d passes through the second pipe portion 28b, the disc portion 27a, and the first pipe portion 28a, and is connected to the space above the flush water surface in the flush water tank main body 26. For this reason, when the water level in the flush water tank main body 26 rises above a predetermined water level, the flush water in the flush water tank main body 26 is discharged through the overflow pipe portion 28.

[0052] The lower end of the ball chain 31 is connected to the disk portion 27a of the drain valve 27, extends through the inside of the first pipe portion 28a, and is connected at the upper end to the drain valve drive mechanism 32 (Fig. 3). As a result, when the ball chain 31 is pulled upward by the drain valve drive mechanism 32 during toilet flushing, the drain valve 27 is lifted up and the disk portion 27a is lifted off the seat surface 26d.

[0053] 5, a shielding plate 29 is attached to the lower part of overflow pipe section 28. This shielding plate 29 is a circular thin plate made of resin, and is disposed inside second pipe section 28b of overflow pipe section 28. The outer diameter of shielding plate 29 is configured to be larger than the smallest inner diameter of overflow pipe section 28. In this embodiment, the smallest inner diameter of overflow pipe section 28 is the inner diameter of first pipe section 28a, and the outer diameter of shielding plate 29 is configured to be larger than the inner diameter of first pipe section 28a.

[0054] Furthermore, shielding plate 29 has a fan-shaped notch 29a extending from the periphery toward the center. By fitting the lower end of ball chain 31 into this notch 29a, shielding plate 29 is suspended approximately at its center by ball chain 31. In this way, shielding plate 29 is attached to the lower part of overflow pipe section 28 so as to be rotatable about a support point at its approximate center. In other words, shielding plate 29 is movably attached to the lower part of overflow pipe section 28.

[0055] Next, the structure of the mounting portion of the shielding plate 29 will be described in detail with reference to Figures 6 and 7. Note that Figure 6 shows an enlarged view of the lower part of the drain valve 27 with the shielding plate 29 removed.

[0056] As shown in Figure 6, a circular opening 27b is provided in the disk portion 27a of the drain valve 27, and three support arms 27c extending toward the center of the opening 27b are provided in the opening 27b. These support arms 27c support an engagement portion 27d at the center of the opening 27b. That is, the support arms 27c include two support arms 27c extending in a straight line on both sides of the engagement portion 27d, and one support arm 27c extending from the engagement portion 27d at a right angle to the two support arms 27c. These three support arms 27c connect the engagement portion 27d to the inner periphery of the disk portion 27a.

[0057] Furthermore, tilt suppression ribs 27e extend from each of the two support arms 27c. These tilt suppression ribs 27e extend from the two support arms 27c that extend in a straight line in the opposite direction to the other support arm 27c. As will be described later, these tilt suppression ribs 27e are provided to suppress tilting of the suspended shielding plate 29.

[0058] 7, engaging portion 27d is a recess with a notch, and by fitting the small diameter portion of ball chain 31 (the portion between the balls) into this notch, engaging portion 27d and ball chain 31 engage with each other. In this way, ball chain 31 is attached to drain valve 27. Furthermore, shielding plate 29 is positioned below engaging portion 27d, and by fitting the small diameter portion of ball chain 31 into notch 29a of shielding plate 29, shielding plate 29 engages with and is attached to ball chain 31. In this way, shielding plate 29 is suspended by ball chain 31 and attached to the lower part of overflow pipe portion 28 (second pipe portion 28b).

[0059] Furthermore, as shown in Figure 7, when drain valve 27 and shield plate 29 are suspended by ball chain 31, there is a gap between the upper surface of shield plate 29 and the lower end of engagement portion 27d. For this reason, shield plate 29 is attached to drain valve 27 so that it can rotate about a support point that is approximately in the center of shield plate 29. Therefore, when the water level in flush water tank body 26 rises and flush water flows in from the upper end of overflow pipe section 28, shield plate 29 rotates about the support point so as to allow the flush water that falls from above to escape. For this reason, even though shield plate 29 is provided at the bottom of overflow pipe section 28, it does not significantly hinder the discharge of flush water that has flowed into overflow pipe section 28.

[0060] Furthermore, when the shielding plate 29 rotates and tilts significantly, the upper surface of the shielding plate 29 comes into contact with each support arm 27c or the tilt suppressing rib 27e, thereby restricting the tilt of the shielding plate 29. Each support arm 27c extends in three directions from the engagement portion 27d, and a tilt suppressing rib 27e is provided in the direction in which no support arm 27c is provided. Therefore, regardless of the direction in which the shielding plate 29 tilts, the shielding plate 29 comes into contact with the support arm 27c or the tilt suppressing rib 27e, thereby restricting the tilt of the shielding plate 29. Therefore, a portion of the support arm 27c and the tilt suppressing rib 27e function as a movement restricting portion that restricts the range of movement of the shielding plate 29. Note that in this embodiment, each support arm 27c and the tilt suppressing rib 27e are configured so that the tilt of the shielding plate 29 is within approximately 5 degrees with respect to the horizontal plane in any direction.

[0061] On the other hand, because the shielding plate 29 is made of resin with a lower density than water, it is pushed up by buoyancy when the space below the drain valve 27 is filled with flush water. When the shielding plate 29 is pushed up, its upper surface abuts against the support arms 27c and the tilt suppression rib 27e. When the shielding plate 29 is pushed up and abuts against the support arms 27c and the tilt suppression rib 27e, the shielding plate 29 is oriented horizontally (parallel to the disk portion 27a of the drain valve 27). When the shielding plate 29 is oriented horizontally, flush water is less likely to flow into the overflow pipe portion 28 from below the drain valve 27. That is, in this embodiment, the movable shielding plate 29 acts to suppress the inflow of flush water from below the overflow pipe portion 28.

[0062] Next, with new reference to FIG. 8, the operation of the flush toilet apparatus 1 according to an embodiment of the present invention will be explained. FIG. 8 is a cross-sectional view showing the flow of flush water within flush water tank body 26 and near drain outlet 30e when drain valve 27 is open.

[0063] First, when the flush toilet apparatus 1 is in a standby state, the inside of the jet water conduit 16 extending from the inlet 2a is filled with flush water up to the water level of the water seal surface W (water level W in Figure 8), and the jet water conduit 16 is sealed with flush water. The height of this water seal surface W is determined by the height of the top 8d (Figure 2) of the drain trap pipe 8, and is the same as the level of the water stored in the bowl section 6. As a result, when the drain valve 27 is seated on the seat surface 26d and the flush toilet apparatus 1 is in a standby state, the space between the seat surface 26d and the water seal surface W of the jet water conduit 16 forms an air space. This air space communicates with the space above the surface of the flush water stored in the flush water tank main body 26, via the overflow pipe section 28 of the drain valve 27.

[0064] Next, when the user performs the flushing operation on the flush toilet device 1, a controller (not shown) provided in the flush toilet device 1 sends a control signal to the rim water spouting solenoid valve 24b (Figure 1) of the valve unit 24, causing it to open. As a result, flush water supplied from the water supply passes through the rim water spouting solenoid valve 24b and the rim water conduit 12 and is discharged from the rim water outlet 10. The flush water discharged from the rim water outlet 10 forms a swirling flow above the waste receiving surface 18 of the bowl section 6, cleaning the waste receiving surface 18.

[0065] When a predetermined time has elapsed after the rim water discharge solenoid valve 24b has been opened, the controller (not shown) sends a control signal to the drain valve drive mechanism 32 (Figure 3), which activates a motor (not shown) provided in the drain valve drive mechanism 32 and raises the drain valve 27 from the seat surface 26d of the flush water tank main body 26. This causes the disk portion 27a of the drain valve 27 to be pulled away from the seat surface 26d, and the flush water that had been stored in the flush water tank main body 26 flows through the drain passage 26b of the flush water tank main body 26 into the inlet 2a (Figure 8) of the flush toilet main body 2, and then passes through the jet water conduit 16 to be discharged from the jet water discharge port 14. The discharge of water from the jet water discharge port 14 induces a siphon phenomenon in the drain trap pipe 8, and the flush water and waste in the bowl portion 6 are discharged through the drain trap pipe 8.

[0066] Here, when the disk portion 27a of the drain valve 27 is lifted up from the seat surface 26d of the flush water tank body 26, the flush water in the flush water tank body 26 starts to flow towards the centre of the drain passage 26b (drain outlet) all at once. In other words, the moment the drain valve 27 is lifted up, the flush water in the flush water tank body 26 flows inward from the entire periphery of the gap between the underside of the disk portion 27a and the seat surface 26d, and collides near the centre of the drain passage 26b.

[0067] Most of the flush water that collides near the centre of drain passage 26b falls towards jet water conduit 16, but some of the flush water splashes up. In other words, immediately after drain valve 27 is pulled up, the pressure of the flush water in the space below drain valve 27 rises all at once, and some of the flush water tries to escape upward. In the flush water tank device 4 of this embodiment, a shielding plate 29 is attached to the bottom of overflow pipe section 28 provided on drain valve 27, so that some of the flush water escaping upward is blocked by shielding plate 29. This prevents flush water below drain valve 27 from flowing into overflow pipe section 28.

[0068] Here, the outer diameter of the shielding plate 29 is configured to be larger than the inner diameter of the first pipe section 28a, which has a smaller inner diameter, of the overflow pipe section 28, so that flush water can be effectively prevented from flowing into the first pipe section 28a. Furthermore, when flush water attempting to escape upward pushes up the shielding plate 29, the upper surface of the shielding plate 29 abuts against the support arm 27c and the tilt suppression rib 27e (FIG. 6), and the shielding plate 29 is oriented approximately horizontally (parallel to the disk section 27a of the drain valve 27). As a result, the gap between the outer periphery of the shielding plate 29 and the inner periphery of the second pipe section 28b becomes narrower, making it even more difficult for flush water to flow into the overflow pipe section 28.

[0069] In this way, by restricting the inflow of flush water into the overflow pipe section 28, immediately after the drain valve 27 is pulled up, the flush water in the flush water tank body 26 is forced more strongly into the jet water conduit 16, increasing the instantaneous flow rate of the jet water discharged from the jet spout 14. This allows the siphon action to be activated early within the drain trap pipe 8, improving the flushing efficiency of the flush toilet.

[0070] As described above, after the drain valve 27 is raised from the seat surface 26d and flush water is discharged from the jet water spouting port 14, a predetermined time later the controller (not shown) sends a control signal to the rim water spouting solenoid valve 24b to close it. This stops rim water spouting from the rim water spouting port 10 and completes one toilet flush.

[0071] On the other hand, if the water level inside the flush water tank main body 26 rises above normal due to a malfunction of the tank water supply solenoid valve 24a or the like and exceeds the height of the upper end of the overflow pipe section 28, flush water will flow into the overflow pipe section 28 from the upper end. The flush water that flows in from the upper end of the overflow pipe section 28 is discharged into the jet water conduit 16 from the lower end. In this way, when flush water flows into the overflow pipe section 28 from the upper end, the shielding plate 29 tilts in accordance with the flush water that has flowed in, and the cross-sectional area of ​​the flow path for discharging the flush water increases. For this reason, the discharge of flush water is not significantly impeded and sufficient drainage performance is ensured in the overflow pipe section 28 even when the shielding plate 29 is provided.

[0072] According to the flush water tank apparatus 4 of the embodiment of the present invention, a shielding plate 29 is provided at the bottom of the overflow pipe section 28, so when the drain valve 27 is opened, it is possible to prevent some of the flush water that flows into the drain opening 30a (drain outlet) from entering the overflow pipe section 28 from the bottom end. As a result, it is possible to increase the initial instantaneous flow rate of flush water that is discharged when the toilet is flushed. Furthermore, because the shielding plate 29 is movable, it can be moved to different positions when the drain valve 27 is opened and when overflow occurs within the flush water tank body 26. As a result, it is possible to fully prevent flush water from entering from the bottom end of the overflow pipe section 28 when the drain valve 27 is opened, while still fully ensuring the function of the overflow pipe section 28 that allows flush water to flow out.

[0073] Furthermore, according to the flush water tank device 4 of this embodiment, the outer diameter of the shielding plate 29 is configured to be larger than the smallest inner diameter of the overflow pipe section 28, so that the shielding plate 29 can effectively prevent flush water from entering the overflow pipe section 28.

[0074] Furthermore, according to the flush water tank apparatus 4 of this embodiment, the shielding plate 29 is supported by hanging it approximately at its centre, and is attached so that it can rotate around the support point of the shielding plate 29. For this reason, when overflow occurs from the flush water tank main body 26, the shielding plate 29 can tilt in any direction, allowing the flush water that flows in from the upper end of the overflow pipe section 28 to flow out into the flush toilet main body 2 without being excessively blocked.

[0075] Furthermore, according to the flush water tank device 4 of this embodiment, a support arm 27c and an inclination suppression rib 27e, which are movement suppression parts that restrict the range of movement of the shielding plate 29, are provided at the bottom of the overflow pipe section 28, so that the range of movement of the shielding plate 29 can be restricted to an appropriate range, making it possible to both suppress the intrusion of flush water from below the shielding plate 29 and discharge flush water that has flowed in from the upper end of the overflow pipe section 28.

[0076] Furthermore, according to the flush water tank device 4 of this embodiment, the shielding plate 29 is made of a resin that has a lower density than water, so when the drain valve 27 is opened, the flush water flowing below causes the shielding plate 29 to float up, effectively preventing the flush water from entering the overflow pipe section 28.

[0077] Furthermore, according to the flush water tank device 4 of this embodiment, the shielding plate 29 is suspended by a ball chain 31, so that the shielding plate 29 can be movably supported in an appropriate position without providing any special structure for supporting the shielding plate 29.

[0078] An embodiment of the present invention has been described above, but various modifications can be made to the above-described embodiment. In particular, in the above-described embodiment, flush water was supplied from the flush water tank device to the jet spout, but the present invention can be applied to any flush water tank device, such as a flush water tank device that supplies flush water to both the jet spout and the rim spout, or a flush water tank device that supplies flush water only to the rim spout. [Explanation of symbols]

[0079] 1 Flush toilet device 2 Flush toilet body 2a Inlet 4. Cleaning water tank device 6 Bowl section 8 Drain trap pipe 8a Entrance 8b Ascending pipe 8c descending pipe 8d top 10 Rim Spout 12 Rim Waterway 14 Jet outlet 16 Jet Waterway 16a Upstream channel 16b Bent flow path 16c Downstream channel 18 Waste receiving surface 20 Rim 21 Shelf 22 Pressure Points 24 Valve unit 24a Tank water supply solenoid valve 24b Rim water outlet solenoid valve 26 Cleaning water tank body 26a Protrusion 26b Drain passage 26c groove 26d seat surface 27 Drain valve 27a Disc section 27b opening 27c Support arm (movement restriction part) 27d Engagement part 27e Tilt control rib (movement control part) 28 Overflow pipe section 28a 1st pipe section 28b 2nd pipe section 29 Shielding plate 29a Notch 30 base plate 30a Drain opening (drain port) 30b Cylindrical part 30c Top recess 30d Bottom recess 30e drain 31 Chain 32 Drain valve drive mechanism 34 O-ring 36 Gasket 38 volts 40 Flow guide section 40a Notch

Claims

1. A flush water tank device that stores flush water for flushing a toilet, a flush water tank body that stores flush water for flushing the toilet; a direct-type drain valve that opens and closes a drain outlet provided in the flush water tank body; an overflow pipe portion provided in the drain valve that discharges flush water from the flush water tank body when the water level in the flush water tank body becomes higher than a predetermined water level; a movable shielding plate provided at the bottom of the overflow pipe portion, which prevents a portion of the flush water flowing into the drain outlet from entering the overflow pipe portion from the bottom end when the drain valve is opened; A flush water tank device comprising:

2. 2. A flush water tank apparatus according to claim 1, wherein the shielding plate has an outer diameter larger than the smallest inner diameter of the overflow pipe portion.

3. 2. A flush water tank apparatus according to claim 1, wherein the shielding plate is supported by being suspended from approximately its center, and is attached so as to be rotatable about the support point of the shielding plate.

4. 2. A flush water tank apparatus according to claim 1, wherein a movement restricting portion is provided at the bottom of the overflow pipe portion to restrict the range of movement of the shielding plate.

5. 2. A flush water tank apparatus according to claim 1, wherein the shielding plate is made of a material having a density lower than that of water.

6. 4. A flush water tank apparatus according to claim 3, further comprising a ball chain for pulling up said drain valve when said drain valve is opened, said shielding plate being suspended by said ball chain.

7. A flush toilet device equipped with a flush water tank device, A flush toilet body, a flush water tank device according to any one of claims 1 to 6, attached to the rear of the flush toilet main body and used to store flush water for flushing the flush toilet main body; A flush toilet apparatus comprising:

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