Flush toilet apparatus

Abstract

The present invention provides a flush toilet apparatus (1) including a flush toilet main body (2), and a flush water tank device (4), in which the flush water tank device includes a flush water tank main body (26), a discharge port (30e), an annular seat surface (26d), a discharge valve (28) seated on the seat surface, an exhaust passage (28b) that communicates between a space below the seat surface and a space above a water surface in the flush water tank main body in a state in which the discharge valve is seated on the seat surface, and a guide part provided in the discharge valve or in a bottom portion of the flush water tank main body to suppress contraction and merging of flows of flush water toward a center from a periphery of the seat surface when the flush water is discharged.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of Japanese Patent Application No. 2024-010040 filed on Jan. 26, 2024 and Japanese Patent Application No. 2024-010041 filed on Jan. 26, 2024, which are hereby incorporated by reference in their entirety for all purposes as if fully set forth herein.BACKGROUND OF THE INVENTIONField of the Invention

[0002] The present invention relates to a flush toilet apparatus, and more particularly, to a flush toilet apparatus that performs flushing with flush water stored in a flush water tank device.Description of the Related Art

[0003] Japanese Patent Laid-Open No. 2017-133246 (Patent Literature 1) discloses a discharge valve device. In this discharge valve device, a valve body of a discharge valve provided in a bottom portion of a storage tank is pulled up from a valve seat of the discharge valve, thereby causing the flush water in the storage tank to flow into a discharge space (passage) to supply the flush water to a toilet main body.

[0004] However, in the discharge valve device disclosed in Patent Literature 1, when the valve body is pulled up from the valve seat, the flush water in the storage tank flows toward a center of the valve seat at a time. As a result, air in the discharge space on a downstream side of the valve seat is entrained in the flush water that has flowed into the discharge space, so that a state occurs in which the air is unlikely to be discharged. This temporarily inhibits the flush water in the storage tank from flowing into the discharge space and causes a reduction in initial instantaneous flow rate of the flush water to be supplied to the toilet main body.

[0005] Accordingly, the present invention has an object to provide a flush toilet apparatus capable of suppressing a reduction in instantaneous flow rate of flush water to be supplied to a flush toilet main body immediately after a discharge valve is opened.SUMMARY OF THE INVENTION

[0006] In order to solve the above-described problem, the present invention provides a flush toilet apparatus that performs flushing with flush water stored in a flush water tank device, the flush toilet apparatus including a flush toilet main body that includes a bowl and a water inlet into which the flush water for flushing the bowl flows, and a flush water tank device that stores the flush water for flushing the bowl, in which the flush water tank device includes a flush water tank main body that stores the flush water, a discharge port from which the flush water in the flush water tank main body is discharged to flow into the water inlet of the flush toilet main body, an annular seat surface provided to surround the discharge port, a discharge valve that is seated on and detached from the seat surface, so that the flush water is discharged and stopped from the flush water tank main body, an exhaust passage that communicates between a space below the seat surface and a space above a water surface of the flush water stored in the flush water tank main body in a state in which the discharge valve is seated on the seat surface, and a guide part provided in the discharge valve or in a bottom portion of the flush water tank main body to suppress contraction and merging of flows of flush water toward a center from a periphery of the seat surface when the flush water in the flush water tank main body is discharged.

[0007] According to the present invention configured as described above, the guide part that suppresses the contraction and merging of the flows of flush water toward the center from the periphery of the seat surface is provided, which suppresses the fact that the air on the downstream side of the seat surface is entrained in the flush water that has flowed in from the periphery of the seat surface. This causes the air on the downstream side of the seat surface to be rapidly discharged through the exhaust passage, suppressing the inhibition of the flows of flush water due to the air, which makes it possible to increase an initial instantaneous flow rate of the flush water to be supplied to the flush toilet main body.

[0008] In the present invention, it is preferable that the guide part is a contraction and merging suppression part provided in the discharge valve, the discharge valve is configured to be pulled upward from the seat surface, and the exhaust passage is provided in the discharge valve and is configured to communicate between a lower end of the contraction and merging suppression part and the space above the water surface of the flush water stored in the flush water tank main body.

[0009] According to the present invention configured as described above, the exhaust passage provided in the discharge valve causes the lower end of the contraction and merging suppression part to communicate with the space above the water surface of the flush water stored in the flush water tank main body, so that the air on the downstream side of the seat surface can be rapidly escaped to the upper side of the water surface of the flush water and the effects of the air on the downstream side of the seat surface can be extremely reduced. This makes it possible to increase the initial instantaneous flow rate of the flush water to be supplied to the flush toilet main body.

[0010] In the present invention, it is preferable that the contraction and merging suppression part is a projection provided in a lower end of the discharge valve and extending downward with respect to the seat surface in a state in which the discharge valve is seated on the seat surface.

[0011] According to the present invention configured as described above, the contraction and merging suppression part is formed by the projection provided in the lower end of the discharge valve and extending downward with respect to the seat surface, which makes it possible to prevent the flows of flush water that has flowed in toward the center of the seat surface from a gap between the discharge valve and the seat surface from being merged with each other as they are. This makes it possible to suppress the contraction and merging of the flows of flush water and increase the instantaneous flow rate of the flush water.

[0012] In the present invention, it is preferable that a water passageway extending from the water inlet of the flush toilet main body is water-sealed by the flush water stored in the flush toilet main body, and an air layer is formed between the seat surface and a water seal surface in the water passageway.

[0013] In a flush toilet apparatus in which the water passageway extending from the water inlet of the flush toilet main body is water-sealed by the flush water stored in the flush toilet main body, air in the air layer cannot be escaped to the water passageway. According to the present invention configured as described above, the contraction and merging of the flows of flush water is suppressed by the contraction and merging suppression part, and the exhaust passage is provided, so that also in the flush toilet apparatus in which the water passageway is water-sealed, the air in the air layer can be easily escaped and the adverse effects of the air in the air layer can be effectively suppressed.

[0014] In the present invention, it is preferable that the flush water tank device further includes a flow guide part which is a wall surface provided outside of the seat surface to surround the seat surface.

[0015] According to the present invention configured as described above, the flush water tank device includes the flow guide part provided outside of the seat surface to surround the seat surface, so that the flow velocity of the flush water toward the center of the seat surface from a gap between the discharge valve and the seat surface can decrease, thereby further suppressing the merging of the flows of flush water with each other.

[0016] In the present invention, it is preferable that a water passageway extending from the water inlet of the flush toilet main body is water-sealed by the flush water stored in the flush toilet main body, a discharge passage in which a cross-sectional area of a flow channel decreases downward is formed between the seat surface and the discharge port, and in a vertical plane, straight lines that pass through an upper end of the flow guide part and are tangent to an inner wall surface of the discharge passage intersect below a water seal surface of the water passageway of the flush toilet main body.

[0017] According to the present invention configured as described above, the straight lines that pass through the upper end of the flow guide part and are tangent to the inner wall surface of the discharge passage intersect below the water seal surface of the water passageway of the flush toilet main body, so that the flows of flush water falling onto the water seal surface through the discharge passage are hardly merged above the water seal surface, making it possible to easily escape the air above the water seal surface from the exhaust passage.

[0018] The present invention provides a flush toilet apparatus that performs flushing with flush water stored in a flush water tank device, the flush toilet apparatus including a flush toilet main body that includes a bowl and a water inlet into which the flush water for flushing the bowl flows, and a flush water tank device that stores the flush water for flushing the bowl, in which the flush water tank device includes a flush water tank main body that stores the flush water, a discharge port from which the flush water in the flush water tank main body is discharged to flow into the water inlet of the flush toilet main body, an annular seat surface provided to surround the discharge port, a discharge valve that is seated on and detached from the seat surface, so that the flush water is discharged and stopped from the flush water tank main body, and an overflow pipe that communicates between a lower end opening that is opened in a space below the seat surface and an upper end opening that is opened on an upper side with respect to a water surface of the flush water stored in the flush water tank main body, in which a water passageway extending from the water inlet of the flush toilet main body is water-sealed by the flush water stored in the flush toilet main body, and the discharge valve is configured to be detached from the seat surface by being turned about a pivot shaft provided on one end portion, and the lower end opening of the overflow pipe is provided on an opposite side of the pivot shaft.

[0019] According to the present invention configured as described above, the lower end opening of the overflow pipe is provided on the opposite side of the pivot shaft of the discharge valve, so that, when the discharge valve is opened, the flush water that has flowed into the seat surface from the opposite side of the pivot shaft hardly flows in the lower end opening of the overflow pipe, making it possible to easily discharge the air between the seat surface and the seal water through the overflow pipe. This makes it possible to easily escape the air in the air layer, and to effectively suppress the adverse effects of the air in the air layer to increase the initial instantaneous flow rate of the flush water to be supplied to the flush toilet main body.

[0020] In the present invention, it is preferable that the flush water tank main body includes a discharge passage formed to extend downward from a bottom surface, the guide part is a flow guide part that is provided in a bottom portion of the flush water tank main body and decreases a flow velocity of the flush water toward a center of the discharge passage in the flush water tank main body, and the flow guide part is an encirclement wall surface provided outside of the seat surface to surround the seat surface.

[0021] According to the present invention configured as described above, the flow guide part that decreases the flow velocity of the flush water toward the center of the discharge passage in the flush water tank main body is provided in the bottom portion of the flush water tank main body, so that the horizontal component of the flow velocity of the flush water toward the center of the discharge passage is reduced. As a result, the flush water flowing out from the flush water tank main body easily flows along the inner wall surface of the discharge passage provided inside of the seat surface, making it possible to suppress the separation of the flows of flush water from the inner wall surface of the discharge passage. This makes it possible to increase the instantaneous flow rate of the flush water flowing out from the flush water tank main body and improve the flushing performance of the flush toilet main body. The flow guide part is formed from the encirclement wall surface provided outside of the seat surface to surround the seat surface, so that the flush water toward the center of the seat surface flows over the encirclement wall surface, which makes it possible to reduce the horizontal component of the flow velocity of the flush water toward the center of the seat surface.

[0022] In the present invention, it is preferable that the flow guide part has an upper end located above a tangent line in an inlet of the discharge passage in a vertical cross section.

[0023] According to the present invention configured as described above, the upper end of the flow guide part is located above the tangent line of the inlet of the discharge passage in the vertical cross section, and thus the flush water toward the center of the seat surface needs to flow over the higher flow guide part, which makes it possible to sufficiently reduce the horizontal component of the flow velocity toward the center of the seat surface.

[0024] In the present invention, it is preferable that the discharge valve is configured to be pulled upward from the seat surface, and in a state in which the discharge valve is pulled up to a highest position, a vertical distance from an upper end of the encirclement wall surface to the discharge valve is a half or more of a vertical distance from the seat surface to the discharge valve.

[0025] According to the present invention configured as described above, in a state where the discharge valve is pulled up to the highest position, the vertical distance from the upper end of the encirclement wall surface to the discharge valve is a half or more of the vertical distance from the seat surface to the discharge valve, so that the sufficient cross-sectional area of the flow channel of the flush water can be ensured between the upper end of the encirclement wall surface and the discharge valve. Therefore, it is possible to avoid a reduction in instantaneous flow rate due to the provision of the encirclement wall surface.

[0026] In the present invention, it is preferable that the encirclement wall surface surrounding the seat surface has cuts formed in portions of the encirclement wall surface.

[0027] According to the present invention configured as described above, the encirclement wall surface surrounding the seat surface has cuts formed in portions of the encirclement wall surface. Therefore, in the cut portions, the relatively large horizontal component of the flow velocity can be maintained, and the horizontal component of the flow velocity toward the center of the seat surface can be adjusted depending on the size of cuts.

[0028] According to the flush toilet apparatus of the present invention, it is possible to suppress a reduction in instantaneous flow rate of the flush water to be supplied to the flush toilet main body immediately after the discharge valve is opened.BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 is a plan view illustrating a flush toilet apparatus according to a first embodiment of the present invention;

[0030] FIG. 2 is a cross-sectional side view taken along a line II-II in FIG. 1, in the flush toilet apparatus according to the first embodiment of the present invention;

[0031] FIG. 3 is an enlarged cross-sectional view illustrating a connection portion between a flush toilet main body and a flush water tank main body in the flush toilet apparatus according to the first embodiment of the present invention;

[0032] FIG. 4 is an enlarged cross-sectional view illustrating a portion of a discharge port of the flush water tank main body provided in the flush toilet apparatus according to the first embodiment of the present invention;

[0033] FIG. 5 is a top view illustrating the flush water tank main body provided in the flush toilet apparatus according to the first embodiment of the present invention;

[0034] FIG. 6 is an enlarged cross-sectional view illustrating a discharge valve that is seated on a seat surface in the flush toilet apparatus according to the first embodiment of the present invention;

[0035] FIG. 7 is a cross-sectional view illustrating flows of flush water in the flush water tank main body when the discharge valve is opened in the flush toilet apparatus according to the first embodiment of the present invention;

[0036] FIG. 8 is a cross-sectional view illustrating flows of flush water in a flush water tank main body in a flush toilet apparatus according to a comparative example;

[0037] FIG. 9 is a schematic enlarged cross-sectional view illustrating a portion of a flush water tank device in a flush toilet apparatus according to a second embodiment of the present invention;

[0038] FIG. 10 is an enlarged cross-sectional view illustrating a connection portion between a flush toilet main body and a flush water tank main body in a flush toilet apparatus according to a third embodiment of the present invention;

[0039] FIG. 11 is a top view illustrating a flush water tank main body according to a comparative example; and

[0040] FIG. 12 is a top view illustrating a flush water tank main body according to a modified example of the flush water tank device according to the third embodiment of the present invention.DETAILED DESCRIPTION OF THE INVENTION

[0041] Next, flush toilet apparatuses according to embodiments of the present invention will be described with reference to the accompanying drawings.

[0042] FIG. 1 is a plan view illustrating a flush toilet apparatus according to a first embodiment of the present invention. FIG. 2 is a cross-sectional side view taken along a line II-II in FIG. 1.

[0043] As illustrated in FIGS. 1 and 2, a flush toilet apparatus 1 according to the first embodiment of the present invention is a siphon jet flush toilet, and includes a ceramic flush toilet main body 2, resin toilet seat and toilet lid (not illustrated) that are arranged on an upper surface of the flush toilet main body 2, and a flush water tank device 4 that is arranged on a rear upper portion of the flush toilet main body 2 and is covered with a resin cover (not illustrated).

[0044] The flush toilet main body 2 is formed with a bowl 6 that receives waste, a water discharge trap pipe 8 that is provided in a bottom portion of the bowl 6 and for discharging waste using a siphon action, a rim spout port 10 that performs rim spout, a rim conduit 12 for guiding the flush water to the rim spout port, a jet spout port 14 that performs jet spout, and a jet conduit 16 for guiding the flush water to the jet spout port 14.

[0045] The bowl 6 includes a bowl-like waste receiving surface 18, a rim 20 formed along at a top edge of the bowl 6, and a shelf 21 formed between the waste receiving surface 18 and the rim 20. Furthermore, the bowl 6 includes a well portion 22 that is formed in a region below the waste receiving surface 18 and is connected to the water discharge trap pipe 8. A water seal surface W is formed inside of the well portion 22.

[0046] The water discharge trap pipe 8 includes an inlet 8a, an ascending conduit 8b extending upward from the inlet 8a, a descending conduit 8c extending downward from the ascending conduit 8b, and a top portion 8d that is located between the descending conduit 8c and the ascending conduit 8b and defines a water seal level. Here, a lower end of the descending conduit 8c of the water discharge trap pipe 8 is connected to a discharge pipe (not illustrated) via a discharge socket (not illustrated).

[0047] The rim spout port 10 is formed in a left rear portion of the rim 20 when the flush toilet main body 2 is viewed from front. The rim spout port 10 spouts the flush water toward the front, so that this flush water is adapted to circulate on an inner peripheral surface of the rim 20 and a shelf surface of the shelf 21 while flowing downward toward the waste receiving surface 18.

[0048] The rim conduit 12 is formed into a tapered shape in which a flow channel cross section is gradually reduced toward the rim spout port 10. The flush water is supplied to the rim conduit 12 from a waterworks via the flush water tank device 4, and the water supply pressure of the waterworks is used so that the flush water spouts from the rim spout port 10.

[0049] The jet spout port 14 is formed in the bottom portion of the bowl 6. The jet spout port 14 is arranged to face the inlet 8a of the water discharge trap pipe 8 and is directed to the inlet 8a of the water discharge trap pipe 8. The jet spout port 14 spouts the flush water toward the inlet 8a of the water discharge trap pipe 8, and this flush water flows into the water discharge trap pipe 8 to activate a siphon action.

[0050] The jet conduit 16 includes an upstream side flow channel 16a extending forward from the flush water tank device 4, a bending flow channel 16b bending from the upstream side flow channel, and a downstream side flow channel 16c extending rearward from the bending flow channel to be connected to the jet spout port 14. The flush water is supplied to the jet conduit 16 from a flush water tank main body 26 of the flush water tank device 4, and a head pressure of the flush water is used so that the flush water spouts from the jet spout port 14. Thus, in the present embodiment, the flush water to be discharged from the rim spout port 10 is supplied directly from the waterworks, and the flush water to be discharged from the jet spout port 14 is supplied from the flush water tank main body 26 (FIG. 1). However, as a modified example, the present invention can be applied to a flush toilet apparatus in which the total amount of the flush water to be discharged is supplied from the flush water tank.

[0051] Next, with renewed reference to FIGS. 3 to 6, a configuration of the flush water tank device 4 of the first embodiment of the present invention will be described.

[0052] FIG. 3 is an enlarged cross-sectional view illustrating a connection portion between the flush toilet main body 2 and the flush water tank main body 26 in the flush toilet apparatus 1 of the present embodiment. FIG. 4 is an enlarged cross-sectional view illustrating a portion of a discharge port of the flush water tank main body 26 provided in the flush water tank device 4. FIG. 5 is a top view of the flush water tank main body 26 provided in the flush water tank device 4. FIG. 6 is an enlarged cross-sectional view illustrating a discharge valve that is seated on a seat surface.

[0053] As illustrated in FIGS. 1 and 2, the flush water tank device 4 includes a valve unit 24 that performs supply and stop of the flush water from the waterworks, the resin flush water tank main body 26 in which the flush water supplied via the valve unit 24 is stored, and a discharge valve 28 that performs discharge and stop of the flush water from the flush water tank main body 26.

[0054] The valve unit 24 includes an electromagnetic valve 24a for supplying water to a tank, a rim spout electromagnetic valve 24b, and the like, and is configured to control supply and stop of tap water supplied from the waterworks into the flush water tank main body 26 and discharge and stop of tap water from the rim spout port 10.

[0055] As illustrated in FIG. 3, the flush water tank main body 26 is configured to store the flush water for flushing the flush toilet main body, and is fixed to the flush toilet main body 2 via a base plate 30. The discharge valve 28 and a discharge valve driving mechanism 32 are arranged in the flush water tank main body 26. When the discharge valve 28 is lifted by the discharge valve driving mechanism 32, the discharge valve 28 is opened, and the flush water is discharged from the flush water tank main body 26. The flush water discharged from the flush water tank main body 26 flows into the jet conduit 16 provided in the flush toilet main body 2 through a water inlet 2a provided in a rear upper surface of the flush toilet main body 2. That is, in the present embodiment, the jet conduit 16 forms a water passageway extending from the water inlet 2a in the flush toilet main body 2.

[0056] In the present embodiment, the flush water tank main body 26 is a small resin tank having a volume of about 2 liters. As illustrated in FIG. 2, a lower portion of the flush water tank main body 26 is arranged below an upper surface of the rim 20 of the flush toilet main body 2 and above the top portion 8d of the water discharge trap pipe 8. Thus, the flush toilet apparatus 1 is a low-silhouette type toilet. In the present embodiment, the flush water in the flush water tank main body 26 is discharged from the jet spout port 14 by gravity.

[0057] As illustrated in FIG. 3, an annular projection 26a projecting downward is provided on a bottom surface of the flush water tank main body 26, and the inside of this annular projection 26a forms a discharge passage 26b formed to extend downward from the bottom surface of the flush water tank main body 26. Furthermore, a groove 26c is formed on an outer peripheral surface of the projection 26a, and an annular O-ring 34 is fitted into this groove 26c. On the other hand, a circular discharge opening 30a is provided in a base plate 30 that supports the flush water tank main body 26. A circular opening in a lower end of the discharge passage 26b is formed to have a diameter substantially equal to that of the discharge opening 30a provided in the base plate 30, so that the discharge passage 26b and the discharge opening 30a are smoothly continuous to each other. Then, in the present embodiment, the lower end of the discharge opening 30a functions as a discharge port 30e of the flush water tank device 4. Note that the discharge port may be formed integrally with the flush water tank main body.

[0058] A cylindrical portion 30b projecting downward is provided in a bottom surface of the base plate 30 to surround the discharge opening 30a. An annular upper surface concave portion 30c is formed in an upper surface of the bottom surface of the base plate 30 to surround the discharge opening 30a. On the other hand, an annular lower surface concave portion 30d is formed in a lower surface of the bottom surface of the base plate 30 to surround the cylindrical portion 30b.

[0059] Furthermore, the projection 26a projecting from the bottom surface of the flush water tank main body 26 is received in the upper surface concave portion 30c formed in the upper surface of the base plate 30. Thus, when the projection 26a of the flush water tank main body 26 is fitted into the upper surface concave portion 30c of the base plate 30, the O-ring 34 arranged on the outer periphery of the projection 26a is crushed in the radial direction of the discharge passage 26b, so that a gap between the flush water tank main body 26 and the base plate 30 is sealed.

[0060] On the other hand, packing 36 is arranged in the annular lower surface concave portion 30d formed in the lower surface of the base plate 30. The packing 36 is formed in an annular shape as a whole, is fitted around the cylindrical portion 30b formed in an inner periphery of the lower surface concave portion 30d, and is received in the lower surface concave portion 30d. The base plate 30 is fixed to the rear upper surface of the flush toilet main body 2 by a plurality of bolts 38 (only one bolt is illustrated in FIG. 3).

[0061] This causes the packing 36 arranged in the lower surface concave portion 30d in the lower surface of the base plate 30 to be compressed between the base plate 30 and the flush toilet main body 2. That is, in a state in which 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 lower surface concave portion 30d of the base plate 30 and a peripheral edge of the water inlet 2a in the upper surface of the flush toilet main body 2. This ensures the watertightness between the base plate 30 and the flush toilet main body 2.

[0062] Next, as illustrated in FIG. 4, the discharge passage 26b is a passage formed to extend downward from the bottom surface of the flush water tank main body 26, has a circular cross section, and is configured so that a cross-sectional area of a flow channel decreases downward. An inner wall surface of the discharge passage 26b is curved to project upward, in a vertical cross section illustrated in FIG. 4. Furthermore, an annular seat surface 26d (FIG. 5) is provided in an inlet at an upper end of the discharge passage 26b to surround the inlet. The seat surface 26d is an annular surface with a narrow width, and the discharge valve 28 is seated on and detached from this seat surface 26d, whereby the discharge port of the flush water tank main body 26 is opened and closed, so that the flush water is discharged and stopped.

[0063] That is, when the bowl 6 of the flush toilet main body 2 is flushed, the discharge valve 28 is lifted by the discharge valve driving mechanism 32 (FIG. 3) from a valve closed position P1 indicated by a broken line in FIG. 4 to a valve opened position P2 indicated by a dashed dotted line. In a state in which the discharge valve 28 is in the valve closed position P1 and is seated on the seat surface 26d, the discharge of the flush water from the flush water tank main body 26 is stopped. Then, when the discharge valve 28 is moved to the valve opened position P2, and is detached from the seat surface 26d, the flush water is discharged from the flush water tank main body 26.

[0064] Furthermore, as illustrated in FIGS. 4 and 5, a flow guide part 40 is provided in a bottom portion of the flush water tank main body 26 to surround the periphery of the seat surface 26d. This flow guide part 40 is an encirclement wall surface provided to vertically rise on the outside of the seat surface 26d to surround the seat surface 26d, and is formed concentrically with the circular seat surface 26d. When the flow guide part 40 is provided in this manner, the flow velocity of the flush water toward a center C of the discharge passage 26b is reduced in the flush water tank main body 26.

[0065] As illustrated in FIG. 4, the encirclement wall surface forming the flow guide part 40 is configured so that an upper end thereof is located above a tangent line L1 tangent to the inner wall surface of the discharge passage 26b in the inlet at the upper end of the discharge passage26b. When the flow guide part 40 is configured in this manner, the flush water flowing toward the center C of the discharge passage 26b in the vicinity of the bottom surface of the flush water tank main body 26 hits against the flow guide part 40 and temporarily flows upward, so that a velocity component of the flush water toward the center C of the discharge passage 26b is reduced.

[0066] Furthermore, in the present embodiment, the encirclement wall surface forming the flow guide part 40 has cuts at four sites on the circumference. That is, as illustrated in FIG. 5, in the flow guide part 40, four cuts 40a are provided at equal intervals on the circumference, and in a portion provided with each cut, the height of the encirclement wall surface is set to be lower. Thus, in the portion provided with each cut 40a, the velocity component of the flush water toward the center C of the discharge passage 26b from the periphery of the discharge port is hardly reduced. Therefore, the average magnitude of the velocity component toward the center C of the discharge passage 26b can be adjusted depending on the number and size of cuts 40a provided in the flow guide part 40.

[0067] In a state in which the discharge valve 28 is pulled up to the valve opened position P2 which is the highest as indicated by a dashed dotted line in FIG. 4, a vertical distance D1 from an upper end of the flow guide part 40 forming the encirclement wall surface to a lower surface of the discharge valve 28 is a half or more of a vertical distance D2 from the seat surface 26d to the lower surface of the discharge valve 28. When the distance from the upper end of the flow guide part 40 to the discharge valve 28 is set in this manner, a sufficient cross-sectional area of a flow channel can be ensured between the flow guide part 40 and the discharge valve 28 while providing the flow guide part 40 around the seat surface 26d.

[0068] Next, a detailed structure of the discharge valve 28 will be described with reference to FIG. 6.

[0069] First, as illustrated in FIG. 6, in a standby state of the flush toilet apparatus 1, the interior of the jet conduit 16 which is a water passageway extending from the water inlet 2a is filled with the flush water to a water level of the water seal surface W, so that the jet conduit 16 is water-sealed by the flush water. The height of this water seal surface W is defined by a height of the top portion 8d (FIG. 2) of the water discharge trap pipe 8, and is the same as a water level of storage water stored in the bowl 6. Thus, when the discharge valve 28 is seated on the seat surface 26d, and the flush toilet apparatus 1 is in a standby state, a space between the seat surface 26d and the water seal surface W of the jet conduit 16 serves as an air layer A.

[0070] Furthermore, as illustrated in FIG. 6, the discharge valve 28 includes a disk part 28a seated on the seat surface 26d, an exhaust passage 28b extending vertically upward from an upper surface of this disk part 28a, a contraction and merging suppression part 28c extending downward from a lower surface of the disk part 28a, and a bead chain 28d extending vertically upward in the exhaust passage 28b from a center of the disk part 28a. Note that in the present embodiment, the contraction and merging suppression part 28c functions as a guide part provided in the discharge valve 28 to suppress the contraction and merging of the flows of flush water toward the center from the periphery of the seat surface 26d when the flush water in the flush water tank main body 26 is discharged.

[0071] The disk part 28a is a flat plate formed in a doughnut plate shape having an outer diameter larger than that of the seat surface 26d, and when the disk part 28a is seated on the seat surface 26d, the discharge of the flush water in the flush water tank main body 26 is stopped.

[0072] The exhaust passage 28b is a cylindrical pipe extending vertically upward from the upper surface of the disk part 28a and concentrically with the disk part 28a, and the upper end of the exhaust passage 28b extends above a water surface of the flush water stored in the flush water tank main body 26 in the standby state of the flush toilet apparatus 1 (FIG. 3). Therefore, in a state in which the discharge valve 28 is seated on the seat surface 26d, the air layer A below the seat surface 26d and a space above the water surface of the flush water stored in the flush water tank main body 26 communicate with each other through the exhaust passage 28b. In other words, the jet conduit 16 is sealed by the water seal surface W, so that a space between the seat surface 26d and the water seal surface W of the jet conduit 16 communicates with the outside air only through the exhaust passage 28b.

[0073] The contraction and merging suppression part 28c is a cylindrical projection extending downward and concentrically with the disk part 28a from a lower surface of the disk part 28a, and the lower end of the contraction and merging suppression part 28c is open. This contraction and merging suppression part 28c extends to project downward with respect to the seat surface 26d in a state in which the discharge valve 28 is seated on the seat surface 26d. Then, the air layer A under the seat surface 26d communicates with the space above the water surface of the flush water in the flush water tank main body 26 through the contraction and merging suppression part 28c, the disk part 28a, and the exhaust passage 28b. As described later, when the contraction and merging suppression part 28c is provided in the discharge valve 28, the contraction and merging of the flows of flush water toward the center from the periphery of the seat surface 26d is suppressed when the flush water in the flush water tank main body 26 is discharged.

[0074] The bead chain 28d has a lower end connected to the disk part 28a of the discharge valve 28 and extending through the inside of the exhaust passage 28b, and an upper end connected to the discharge valve driving mechanism 32 (FIG. 3). Thus, when the bead chain 28d is pulled upward by the discharge valve driving mechanism 32 during a toilet flush, the discharge valve 28 is lifted and the disk part 28a is detached from the seat surface 26d.

[0075] Furthermore, in a state in which the discharge valve 28 is seated on the seat surface 26d as illustrated in FIG. 6, a vertical distance H1 from the seat surface 26d to a lower end of the contraction and merging suppression part 28c is configured to be ⅓ or more of a vertical distance H2 from the seat surface 26d to the water seal surface W of the jet conduit 16. A horizontal cross-sectional area of the outer periphery of the contraction and merging suppression part 28c is configured to be ½ or more of an inner area of the seat surface 26d. When the space between the seat surface 26d and the water seal surface W of the jet conduit 16 is occupied by the contraction and merging suppression part 28c in this manner, the contraction and merging of the flows of flush water can be suppressed when the flush water in the flush water tank main body 26 starts to flow into the inside of the seat surface 26d.

[0076] Furthermore, as illustrated in FIG. 6, in the vertical plane, straight lines L2 that pass through the upper end of the flow guide part 40 and are tangent to the inner wall surface of the discharge passage 26b intersect below the water seal surface W of the jet conduit 16 of the flush toilet main body 2. When the flow guide part 40 and the discharge passage 26b are configured in this manner, it is possible to suppress the fact that the flows of flush water that has flowed in along the inner wall surface of the discharge passage 26b from the periphery of the seat surface 26d over the upper end of the flow guide part 40 are merged with each other before flowing down on the water seal surface W. This causes air in the air layer A below the seat surface 26d to be entrained in the flush water that has flowed in from the periphery of the seat surface 26d, making it possible to suppress disturbing of the flows of flush water.

[0077] Next, with renewed reference to FIGS. 7 and 8, an operation of the flush toilet apparatus 1 according to the first embodiment of the present invention will be described.

[0078] FIG. 7 is a cross-sectional view illustrating flows of flush water in the flush water tank main body 26 when the discharge valve 28 is opened. FIG. 8 is a cross-sectional view illustrating flows of flush water in a flush water tank main body in a flush toilet apparatus according to a comparative example.

[0079] First, when a user performs a flushing operation of the flush toilet apparatus 1, a controller (not illustrated) provided in the flush toilet apparatus 1 transmits a control signal to the rim spout electromagnetic valve 24b (FIG. 1) of the valve unit 24 to open the rim spout electromagnetic valve 24b.

[0080] This causes the flush water supplied from the waterworks to be discharged from the rim spout port 10 through the rim spout electromagnetic valve 24b and the rim conduit 12. The flush water discharged from the rim spout port 10 forms a circulating flow on the waste receiving surface 18 of the bowl 6, so that the waste receiving surface 18 is flushed.

[0081] When a predetermined period of time has elapsed following opening of the rim spout electromagnetic valve 24b, the controller (not illustrated) transmits a control signal to the discharge valve driving mechanism 32 (FIG. 3) to activate a motor (not illustrated) provided in the discharge valve driving mechanism 32, so that the discharge valve 28 is pulled up from the seat surface 26d of the flush water tank main body 26. This causes the disk part 28a of the discharge valve 28 to be detached from the seat surface 26d, so that the flush water that has been stored in the flush water tank main body 26 flows into the water inlet 2a (FIG. 3) of the flush toilet main body 2 through the discharge passage 26b of the flush water tank main body 26 and is discharged from the jet spout port 14 through the jet conduit 16. The water spouting from the jet spout port 14 induces a siphon phenomenon in the water discharge trap pipe 8, so that the flush water and waste in the bowl 6 are discharged through the water discharge trap pipe 8.

[0082] Here, when the disk part 28a of the discharge valve 28 is pulled up from the seat surface 26d of the flush water tank main body 26, the flush water in the flush water tank main body 26 starts to flow toward the center C of the discharge passage 26b (discharge port) at a time. That is, at a moment when the discharge valve 28 is pulled up, the flush water in the flush water tank main body 26 flows toward the center C of the discharge passage 26b from a gap between the lower surface of the disk part 28a and the seat surface 26d, and then falls downward in the discharge passage 26b.

[0083] At this time, the contraction and merging suppression part 28c is provided in the lower surface of the disk part 28a to project downward, so that the flush water toward the center C of the discharge port 30e from the periphery of the seat surface 26d hits against the outer peripheral surface of the contraction and merging suppression part 28c and falls downward. This causes the majority of flush water that has flowed into the inside of the seat surface 26d to smoothly flow into the water inlet 2a of the flush toilet main body 2 along the inner wall surface of the discharge passage 26b

[0084] On the other hand, air in a space (air layer A) between the seat surface 26d and the water seal surface W of the jet conduit 16 is pushed out, when the flush water flows into the space, to flow into the exhaust passage 28b, and flows out to a space above the water surface of the flush water tank main body 26. At this time, the flush water flows along the inner wall surface of the discharge passage 26b, making it difficult for the flush water to be mixed with the air in the air layer A, so that the air rapidly flows into the exhaust passage 28b and is discharged to the atmosphere.

[0085] That is, the “contraction and merging” meaning that the flows of flush water flowing toward the center C of the discharge port 30e from the periphery of the seat surface 26d are merged with each other is suppressed, so that the air in the air layer A is rapidly discharged through the exhaust passage 28b located at the center of the seat surface 26d. This causes the air in the air layer A to be entrained in the flush water, so that the inhibition of the rapid flows of flush water can be suppressed. As a result, immediately after the discharge valve 28 is opened, an instantaneous flow rate of the flush water discharged from the flush water tank main body 26 can be increased.

[0086] In contrast, in a case where a contraction and merging suppression part is not provided in a discharge valve 228, and a flow guide part is not provided around a seat surface 226d as in a comparative example illustrated in FIG. 8, the flush water in a flush water tank main body 226 flows toward a center C of a discharge port at a time when the discharge valve 228 is detached from a seat surface 226d. That is, as illustrated in FIG. 8, the flush water flows toward the center C from the periphery of the seat surface 226d, and the flows of flush water collide and merge with each other in the vicinity of the center of the discharge port. The flush water, the flows of which have merged with each other in the vicinity of the center of the discharge port, falls through the vicinity of the center of a discharge passage 226b, and a region through which the flush water does not flow temporarily is generated in the peripheral edge of the discharge passage 226b. That is, in a conventional discharge valve 228 in which the contraction and merging suppression part is not provided, immediately after the valve is opened, the contraction and merging of the flows of flush water occurs, so that a substantial cross-sectional area of the flow channel is reduced. As a result, an instantaneous flow rate of the flush water immediately after the discharge valve 228 is opened is reduced.

[0087] In addition, when the flows of flush water that has flowed toward the center C from the periphery of the seat surface 226d collide with each other in the vicinity of the center of the discharge port, the air existing in the discharge passage 226b is entrained in the flush water, which may cause large air bubbles to be formed in the flush water. Air in such air bubbles is hardly discharged and easily retained inside the discharge passage 226b even when an exhaust passage is provided in the discharge valve 228. The retained air reduces the effective cross-sectional area of the flow channel in the discharge passage 226b, which causes the instantaneous flow rate of the flush water to be reduced immediately after the discharge valve 228 is opened.

[0088] Such a reduction in instantaneous flow rate due to the retained air easily occurs in a flush toilet in which a water passageway extending from a water inlet of a flush toilet main body is water-sealed by the flush water, as in the flush toilet apparatus 1 of the present embodiment. That is, in the flush toilet in which the water passageway is water-sealed by the flush water, the number of paths from which the air retained in the water passageway is escaped is small, and the air is entrained in the flush water, making it easy for the air to be retained. In the flush toilet apparatus 1 of the present embodiment, the contraction and merging suppression part 28c is provided in the discharge valve 28, making it possible to suppress the contraction and merging of the flows of flush water and rapidly discharge the air retained in the water passageway from the exhaust passage 28b, so that the adverse effects caused by the retained air is suppressed.

[0089] Furthermore, in the flush toilet apparatus 1 of the present embodiment, the flow guide part 40 is provided around the annular seat surface 26d to surround the seat surface 26d. Therefore, as illustrated in FIG. 4, the flows toward the center C of the discharge passage 26b from the periphery of the seat surface 26d flow downward into the discharge passage 26b after being temporarily directed upward to flow over the flow guide part 40 as indicated by arrows F1. Then, the flows F1 of flush water flowing into the discharge passage 26b over the flow guide part 40 fall along the inner wall surface of the discharge passage 26b. This makes it possible to suppress the contraction and merging of the flows of flush water at a moment when the discharge valve 28 is pulled up from the seat surface 26d, so that the flush water in the flush water tank main body 26 can smoothly flow into the discharge passage 26b. As a result, the instantaneous flow rate of the flush water flowing into the jet conduit 16 from the flush water tank main body 26 can be increased.

[0090] That is, in the flush toilet apparatus 1 of the present embodiment, when the discharge valve 28 is opened, the flows of flush water toward the center C of the discharge passage 26b are temporarily directed upward by the flow guide part 40, so that the horizontal components of the flows of flush water are appropriately reduced. Therefore, without separation of the flows of flush water flowing into the discharge passage 26b from the inner wall surface of the discharge passage 26b, the flush water can smoothly flow along the inner wall surface of the discharge passage 26b, so that the instantaneous flow rate can be increased.

[0091] As described above, when a predetermined period of time has elapsed following pulling-up of the discharge valve 28 from the seat surface 26d and discharge of the flush water from the jet spout port 14, the controller (not illustrated) transmits a control signal to the rim spout electromagnetic valve 24b to close the rim spout electromagnetic valve 24b. This causes the rim spouting from the rim spout port 10 to be stopped, and one toilet flush is terminated.

[0092] According to the flush toilet apparatus 1 of the first embodiment of the present invention, the contraction and merging suppression part 28c that suppresses the contraction and merging of the flows of flush water toward the center C from the periphery of the seat surface 26d is provided in the discharge valve 28, which suppresses the fact that the air on the downstream side of the seat surface 26d is entrained in the flush water that has flowed in from the periphery of the seat surface 26d. This causes the air on the downstream side of the seat surface to be rapidly discharged through the exhaust passage 28b, suppressing the inhibition of the flows of flush water due to the air, which makes it possible to increase an initial instantaneous flow rate of the flush water to be supplied to the flush toilet main body 2.

[0093] According to the flush toilet apparatus 1 of the present embodiment, the exhaust passage 28b provided in the discharge valve 28 causes the lower end of the contraction and merging suppression part 28c to communicate with the space above the water surface of the flush water stored in the flush water tank main body 26, so that the air on the downstream side of the seat surface 26d can be rapidly escaped to the upper side of the water surface of the flush water and the effects of the air on the downstream side of the seat surface 26d can be extremely reduced. This makes it possible to increase the initial instantaneous flow rate of the flush water to be supplied to the flush toilet main body 2.

[0094] Furthermore, according to the flush toilet apparatus 1 of the present embodiment, the contraction and merging suppression part 28c is formed by a projection provided in the lower end of the discharge valve 28 and extending downward with respect to the seat surface 26d, which makes it possible to prevent the flows of flush water that has flowed in toward the center of the seat surface 26d from a gap between the discharge valve 28 and the seat surface 26d from being merged with each other as they are. This makes it possible to suppress the contraction and merging of the flows of flush water and increase the instantaneous flow rate of the flush water.

[0095] In addition, according to the flush toilet apparatus 1 of the present embodiment, the contraction and merging of the flows of flush water is suppressed by the contraction and merging suppression part 28c, and the exhaust passage 28b is provided, so that also in the flush toilet apparatus 1 in which the jet conduit 16 which is a water passageway is water-sealed, the air in the air layer A can be easily escaped and the adverse effects of the air in the air layer A can be effectively suppressed.

[0096] Furthermore, according to the flush toilet apparatus 1 of the present embodiment, a distance from the seat surface 26d to the lower end of the contraction and merging suppression part 28c is configured to be ⅓ or more of a distance from the seat surface 26d to the water seal surface W of the water passageway, so that the merging of the flows of flush water that has flowed in toward the center C of the seat surface 26d from a gap between the discharge valve 28 and the seat surface 26d with each other can be effectively suppressed, and the contraction and merging of the flows of flush water can be sufficiently suppressed.

[0097] In addition, according to the flush toilet apparatus 1 of the present embodiment, a horizontal cross-sectional area of the contraction and merging suppression part 28c is configured to be ½ or more of an inner area of the seat surface 26d, so that the flows of flush water that has flowed downward with respect to the contraction and merging suppression part 28c are hardly merged and the contraction and merging of the flows of flush water can be sufficiently suppressed.

[0098] Furthermore, according to the flush toilet apparatus 1 of the present embodiment, the flow guide part 40 provided outside of the seat surface 26d is provided to surround the seat surface 26d, so that the flow velocity of the flush water toward the center C of the seat surface 26d from a gap between the discharge valve 28 and the seat surface 26d can decrease, thereby further suppressing the merging of the flows of flush water with each other.

[0099] In addition, according to the flush toilet apparatus 1 of the present embodiment, straight lines that pass through the upper end of the flow guide part 40 and are tangent to the inner wall surface of the discharge passage 26b intersect below the water seal surface W of the jet conduit 16 which is a water passageway of the flush toilet main body 2, so that the flows of flush water falling onto the water seal surface W through the discharge passage 26b are hardly merged above the water seal surface W, making it possible to easily escape the air above the water seal surface W from the exhaust passage 28b.

[0100] Next, a flush toilet apparatus according to a second embodiment of the present invention will be described with reference to FIG. 9.

[0101] FIG. 9 is a schematic enlarged cross-sectional view illustrating a portion of a flush water tank device in the flush toilet apparatus according to the second embodiment of the present invention.

[0102] As illustrated in FIG. 9, a flush toilet apparatus 100 according to the second embodiment of the present invention includes a flush toilet main body 102, and a flush water tank device 104.

[0103] The flush water tank device 104 includes a flush water tank main body 126, a discharge valve 128, and a discharge valve driving mechanism 132. When the discharge valve 128 is opened during a toilet flush, the flush water in the flush water tank main body 126 is discharged, and flows into a water passageway 102b from a water inlet 102a of the flush toilet main body 102.

[0104] A discharge passage 126b extending vertically downward is provided in a bottom portion of the flush water tank main body 126, and when the discharge valve 128 is opened, the flush water in the flush water tank main body 126 is discharged through the discharge passage 126b. That is, the inside of the discharge passage 126b functions as a discharge port from which the flush water in the flush water tank main body 126 is discharged to flow into the water inlet 102a of the flush toilet main body 120. Furthermore, a seat surface 126d is provided around an upper end of the discharge passage 126b, and when the discharge valve 128 is seated on the seat surface 126d, the discharge valve 128 is closed to stop the discharge of the flush water.

[0105] On the other hand, an overflow pipe 130 is connected to the discharge passage 126b. A lower end opening 130a of the overflow pipe 130 is provided in the inner wall surface of the discharge passage 126b, and an upper end opening 130b is located above the water surface of the flush water in the flush water tank main body 126. That is, the overflow pipe 130 extends horizontally from the lower end opening 130a provided in the inner wall surface extending vertically of the discharge passage 126b, is bent vertically, and extends to the upper end opening 130b. The overflow pipe 130 communicates between the atmosphere above the water surface in the flush water tank main body 126 and an air layer A under the seat surface 126d.

[0106] The discharge valve 128 is a float valve that includes a hemispherical float portion 128a, and an arm portion 128b extending from the float portion 128a. A distal end of the arm portion 128b is turnably supported on a pivot shaft 128c extending horizontally. In the present embodiment, the pivot shaft 128c is provided on an opposite side of the lower end opening 130a provided in the discharge passage 126b, as illustrated in FIG. 9. A bead chain 128d is attached to an upper surface of the float portion 128a, and an upper end of the bead chain 128d is connected to the discharge valve driving mechanism 132.

[0107] The discharge valve driving mechanism 132 is provided in an upper portion of the flush water tank device 104, and is configured to pull the bead chain 128d upward during a toilet flush. When the bead chain 128d is pulled upward in a state in which the float portion 128a is seated on the seat surface 126d, the float portion 128a is turned about the pivot shaft 128c, and the float portion 128a is detached from the seat surface 126d. This causes the discharge valve 128 to be opened, so that the flush water in the flush water tank main body 126 flows into the water inlet 102a of the flush toilet main body 102 through the discharge passage 126b. Note that in the present embodiment, the discharge valve driving mechanism 132 is configured by a manual lever (not illustrated), but the discharge valve driving mechanism 132 may be configured by a motor (not illustrated) or the like.

[0108] Next, an operation of the flush toilet apparatus 100 according to the second embodiment of the present invention will be described.

[0109] First, also in the flush toilet apparatus 100 of the present embodiment, the water passageway 102b extending from the water inlet 102a of the flush toilet main body 102 is water-sealed by the flush water stored in the flush toilet main body 102. That is, in the standby state of the flush toilet apparatus 100, the air layer A is formed in a space between the water seal surface W of seal water in the water passageway 102b and the seat surface 126d of the flush water tank main body 126, and is filled with the air.

[0110] Next, when a user performs a flushing operation, the bead chain 128d is pulled upward, whereby the float portion 128a of the discharge valve 128 is turned about the pivot shaft 128c. This causes the float portion 128a to be detached from the seat surface 126d, and the discharge of the flush water in the flush water tank main body 126 is started.

[0111] Here, when the float portion 128a is turned about the pivot shaft 128c, the float portion 128a is largely separated from the seat surface 126d on the opposite side (left side in FIG. 9) of the pivot shaft 128c. Therefore, in particular, immediately after the discharge of the flush water is started, the flush water mainly flows into the discharge passage 126b from a gap between the float portion 128a and the seat surface 126d on the opposite side of the pivot shaft 128c.

[0112] As a result, the flush water in the flush water tank main body 126 flows into the inside of the seat surface 126d from the opposite side of the pivot shaft 128c toward the pivot shaft 128c as indicated by an arrow F in FIG. 9. Thus, a main flow of the flush water flowing into the inside of the seat surface 126d flows into the discharge passage 126b to jump over the lower end opening 130a of the overflow pipe 130 opened on the opposite side of the pivot shaft 128c. Therefore, the air in the air layer A under the seat surface 126d rapidly flows into the lower end opening 130a of the overflow pipe 130 without being entrained in the flush water that has flowed thereinto, and is discharged to the atmosphere from the upper end opening 130b.

[0113] That is, immediately after the discharge of the flush water is started, the flush water flows to jump over the lower end opening 130a provided on the opposite side of the pivot shaft 128c, so that the lower end opening 130a is not blocked by the flush water. As a result, the air in the air layer A can be rapidly discharged through the overflow pipe 130. Accordingly, in the present embodiment, the overflow pipe 130 functions as an exhaust passage. The air in the air layer A can be rapidly discharged in this manner, so that the instantaneous flow rate immediately after the discharge of the flush water is started can be increased without the retained air inhibiting the flows of flush water.

[0114] According to the flush toilet apparatus 100 of the second embodiment of the present invention, the lower end opening 130a of the overflow pipe 130 is provided on the opposite side of the pivot shaft 128c of the discharge valve 128, so that, when the discharge valve 128 is opened, the flush water that has flowed into the seat surface 126d from the opposite side of the pivot shaft 128c hardly flows in the lower end opening 130a of the overflow pipe 130, making it possible to easily discharge the air in the air layer A between the seat surface 126d and the seal water through the overflow pipe 130. This makes it possible to easily escape the air in the air layer A, and to effectively suppress the adverse effects of the air in the air layer A to increase the initial instantaneous flow rate of the flush water to be supplied to the flush toilet main body 2.

[0115] Next, a flush toilet apparatus according to a third embodiment of the present invention will be described with reference to FIGS. 10 and 11.

[0116] The flush toilet apparatus of the present embodiment is different from the above-described first embodiment in a structure of a lower end of the discharge valve. Accordingly, only portions of the flush toilet apparatus according to the third embodiment of the present invention that are different from the first embodiment will be described below, and for the same portions as in the first embodiment, reference is made to the above description of the first embodiment. In particular, a structure of a flush water tank main body in the flush toilet apparatus of the third embodiment of the present invention is the same as the structure of the flush water tank main body in the first embodiment (FIGS. 4 and 5), and these portions are denoted by the same reference numerals as in the first embodiment, and the description thereof is not repeated.

[0117] FIG. 10 is an enlarged cross-sectional view illustrating a connection portion between the flush toilet main body 2 and the flush water tank main body 26 in the flush toilet apparatus 1 of the third embodiment of the present invention.

[0118] As illustrated in FIG. 10, the flush water tank main body 26 is configured to store the flush water for flushing the flush toilet main body, and is fixed to the flush toilet main body 2 via a base plate 30. A discharge valve 328 and a discharge valve driving mechanism 32 are arranged in the flush water tank main body 26. When the discharge valve 328 is lifted by the discharge valve driving mechanism 32, the discharge valve 328 is opened, and the flush water is discharged from the flush water tank main body 26. The flush water discharged from the flush water tank main body 26 flows into a jet conduit 16 provided in the flush toilet main body 2 through a water inlet 2a provided in a rear upper surface of the flush toilet main body 2.

[0119] Furthermore, as illustrated in FIG. 10, the discharge valve 328 includes a disk part 328a seated on the seat surface 26d, an exhaust passage 328b extending vertically upward from an upper surface of this disk part 328a, and a bead chain 328d extending vertically upward in the exhaust passage 328b from a center of the disk part 328a. Thus, the present embodiment is different from the above-described first embodiment in that the contraction and merging suppression part 28c (FIG. 6) is not provided on the lower side of the disk part 328a.

[0120] The disk part 328a is a flat plate formed in a doughnut plate shape having an outer diameter larger than that of the seat surface 26d, and when the disk part 328a is seated on the seat surface 26d, the discharge of the flush water in the flush water tank main body 26 is stopped.

[0121] The exhaust passage 328b is a cylindrical pipe extending vertically upward from the upper surface of the disk part 328a and concentrically with the disk part 328a, and the upper end of the exhaust passage 328b extends above a water surface of the flush water stored in the flush water tank main body 26 in the standby state of the flush toilet apparatus 1.

[0122] The bead chain 328d has a lower end connected to the disk part 328a of the discharge valve 328 and extending through the inside of the exhaust passage 328b, and an upper end connected to the discharge valve driving mechanism 32. Thus, when the bead chain 328d is pulled upward by the discharge valve driving mechanism 32 during a toilet flush, the discharge valve 328 is lifted and the disk part 328a is detached from the seat surface 26d.

[0123] Next, an operation of the flush toilet apparatus according to the third embodiment of the present invention will be described.

[0124] First, when a user performs a flushing operation of the flush toilet apparatus 1, a controller (not illustrated) provided in the flush toilet apparatus 1 transmits a control signal to the rim spout electromagnetic valve 24b (FIG. 1) of the valve unit 24 to open the rim spout electromagnetic valve 24b. This causes the flush water supplied from the waterworks to be discharged from the rim spout port 10 through the rim spout electromagnetic valve 24b and the rim conduit12. The flush water discharged from the rim spout port 10 forms a circulating flow on the waste receiving surface 18 of the bowl 6, so that the waste receiving surface 18 is flushed.

[0125] When a predetermined period of time has elapsed following opening of the rim spout electromagnetic valve 24b, the controller (not illustrated) transmits a control signal to the discharge valve driving mechanism 32 (FIG. 10) to activate a motor (not illustrated) provided in the discharge valve driving mechanism 32, so that the discharge valve 328 is pulled up from the seat surface 26d of the flush water tank main body 26. This causes the discharge valve 328 to be opened, so that the flush water that has been stored in the flush water tank main body 26 flows into the water inlet 2a (FIG. 10) of the flush toilet main body 2 through the discharge passage 26b of the flush water tank main body 26 and is discharged from the jet spout port 14 through the jet conduit 16. The water spouting from the jet spout port 14 induces a siphon phenomenon in the water discharge trap pipe 8, so that the flush water and waste in the bowl 6 are discharged through the water discharge trap pipe 8.

[0126] Here, when the discharge valve 328 is pulled up from the seat surface 26d of the flush water tank main body 26, the flush water in the flush water tank main body 26 starts to flow toward the center C (FIG. 4) of the discharge passage 26b (discharge port) at a time. That is, at a moment when the discharge valve 328 is pulled up, the flush water in the flush water tank main body 26 flows toward the center C of the discharge passage 26b from a gap between the bottom surface of the discharge valve 328 and the seat surface 26d, and then falls downward in the discharge passage 26b.

[0127] At this time, the flow guide part 40 is provided around the annular seat surface 26d to surround the seat surface 26d, so that the flows toward the center C of the discharge passage 26b flow downward into the discharge passage 26b after being temporarily directed upward to flow over the flow guide part 40 as indicated by arrows F1 (FIG. 4). Then, the flows F1 of flush water flowing into the discharge passage 26b over the flow guide part 40 fall along the inner wall surface of the discharge passage 26b. This enables the flush water in the flush water tank main body 26 to smoothly flow into the discharge passage 26b at a moment when the discharge valve 328 is pulled up from the seat surface 26d. As a result, the instantaneous flow rate of the flush water flowing into the jet conduit 16 from the flush water tank main body 26 can be increased.

[0128] In contrast, in a case where the flow guide part 40 is not provided around a seat surface 326d as in a flush water tank main body 326 of a comparative example illustrated in FIG. 11, the flush water flows in toward the center of a discharge passage 326b, at an extremely high flow velocity, from a gap between the bottom surface of the discharge valve 328 and the seat surface 326d at a moment when the discharge valve 328 is pulled up from the seat surface 326d. Therefore, the flush water that has flowed in from the gap between the discharge valve 328 and the seat surface 326d flows substantially in a horizontal direction, as indicated by arrows F3 in FIG. 11. As a result, immediately after the discharge valve 328 is pulled up from the seat surface 326d, the flush water does not flow along the inner wall surface of the discharge passage 326b, so that an effective cross-sectional area of the flow channel is reduced. This reduces an instantaneous flow rate immediately after the discharge valve 328 is pulled up. In other words, in a case where the flow guide part 40 is not provided, the horizontal components of the flows of flush water become too large, and immediately after the discharge valve 328 is opened, the flows of flush water are separated from the inner wall surface of the discharge passage 326b, so that regions B through which the flush water does not flow are generated. As a result, a flow channel resistance increases when the flush water flows into the discharge passage 326b from the flush water tank main body 326, which causes the instantaneous flow rate to be reduced.

[0129] On the other hand, in the flush toilet apparatus of the third embodiment of the present invention illustrated in FIG. 10, when the discharge valve 328 is opened, the flows of flush water toward the center C of the discharge passage 26b are temporarily directed upward by the flow guide part 40 (FIG. 4), so that the horizontal components of the flows of flush water are appropriately reduced. Therefore, without separation of the flows of flush water flowing into the discharge passage 26b from the inner wall surface of the discharge passage 26b, the flush water can smoothly flow along the inner wall surface of the discharge passage 26b, so that the instantaneous flow rate can be increased.

[0130] Furthermore, in the flush toilet apparatus of the present embodiment, a flow guide part 40 is provided in the bottom surface of the flush water tank main body 26 and cuts 40a are provided in the flow guide part 40. In portions in which the cuts 40a are provided, as indicated by the arrows F2 (FIG. 4), the flows of flush water toward the center C of the discharge passage 26b from the periphery of the flow guide part 40 flow into the inside of the flow guide part 40 substantially in the horizontal direction without being directed upward. Therefore, the flush water that has passed through the cuts 40a flows toward the center C of the discharge passage 26b at a relatively high flow velocity, merges with the flush water that has flowed over the flow guide part 40, and then flows into the discharge passage 26b.

[0131] Thus, in the portions in which the cuts 40a are provided in the flow guide part 40, the horizontal component of the flow velocity of the flush water increases, whereas in the portions in which the flush water has flowed over the flow guide part 40, the horizontal component of the flow velocity of the flush water decreases. Therefore, the average flow velocity of the flush water toward the center C of the discharge passage 26b can be adjusted depending on the size and the number of cuts 40a provided in the flow guide part 40. In the present embodiment, the size and the number of cuts 40a provided in the flow guide part 40 are set so that the flow velocity of the flush water toward the center C of the discharge passage 26b is as high as possible within a range that the separation does not occur in the inner wall surface of the discharge passage 26b.

[0132] Thus, when a predetermined period of time has elapsed following pulling-up of the discharge valve 328 from the seat surface 26d and discharge of the flush water from the jet spout port 14, the controller (not illustrated) transmits a control signal to the rim spout electromagnetic valve 24b to close the rim spout electromagnetic valve 24b. This causes the rim spouting from the rim spout port 10 to be stopped, and one toilet flush is terminated.

[0133] According to the flush toilet apparatus of the third embodiment of the present invention, the flow guide part 40 that decreases the flow velocity of the flush water toward the center C of the discharge passage 26b in the flush water tank main body 26 is provided in the bottom portion of the flush water tank main body 26, so that the horizontal component of the flow velocity of the flush water toward the center C of the discharge passage 26b is reduced. As a result, the flush water flowing out from the flush water tank main body 26 easily flows along the inner wall surface of the discharge passage 26b provided inside of the seat surface 26d, making it possible to suppress the separation of the flows of flush water from the inner wall surface of the discharge passage 26b. This makes it possible to increase the instantaneous flow rate of the flush water flowing out from the flush water tank main body 26 and improve the flushing performance of the flush toilet main body 2.

[0134] According to the flush toilet apparatus of the present embodiment, the flow guide part 40 is formed from the encirclement wall surface provided outside of the seat surface 26d to surround the seat surface 26d, so that the flush water toward the center C of the seat surface 26d flows over the encirclement wall surface, which makes it possible to reduce the horizontal component of the flow velocity of the flush water toward the center of the seat surface 26d.

[0135] Furthermore, according to the flush toilet apparatus of the present embodiment, the upper end of the flow guide part 40 is located above the tangent line L1 (FIG. 4) of the inlet of the discharge passage 26b in the vertical cross section, and thus the flush water toward the center C of the seat surface 26d needs to flow over the higher flow guide part 40, which makes it possible to sufficiently reduce the horizontal component of the flow velocity toward the center C of the seat surface 26d.

[0136] In addition, according to the flush toilet apparatus of the present embodiment, in a state where the discharge valve 328 is pulled up to the highest position, the vertical distance D1 (FIG. 4) from the upper end of the encirclement wall surface (flow guide part 40) to the discharge valve 328 is a half or more of the vertical distance D2 from the seat surface 26d to the discharge valve 328, so that the sufficient cross-sectional area of the flow channel of the flush water can be ensured between the upper end of the encirclement wall surface and the discharge valve 328. Therefore, it is possible to avoid a reduction in instantaneous flow rate due to the provision of the encirclement wall surface.

[0137] Furthermore, according to the flush toilet apparatus of the present embodiment, the encirclement wall surface (flow guide part 40) surrounding the seat surface has cuts formed in portions thereof (FIGS. 4 and 5). Therefore, in the cut portions (cuts 40a), the relatively large horizontal component of the flow velocity can be maintained, and the horizontal component of the flow velocity toward the center of the seat surface 26d can be adjusted depending on the size of cuts.

[0138] The embodiments of the present invention have been described above, but various changes may be added to the above-described embodiments.

[0139] For example, in the above-described third embodiment, the encirclement wall surface forming the flow guide part is configured to be separated from the side wall surface of the flush water tank main body, but as illustrated in FIG. 12, a portion of the encirclement wall surface can be integrated with the side wall surface of the flush water tank main body. That is, in a modified example illustrated in FIG. 12, an encirclement wall surface 352 is provided as the flow guide part to surround the periphery of a seat surface 350a of a flush water tank main body 350. The encirclement wall surface 352 is provided concentrically with the annular seat surface 350a and a portion thereof is integrated with one side wall surface 350b of the flush water tank main body 350. Even when a portion of the encirclement wall surface 352 is thus integrated with the side wall surface 350b of the flush water tank main body 350, the horizontal component of the flow velocity toward the center C of the seat surface 350a can be reduced by the encirclement wall surface 352, and the instantaneous flow rate of the flush water flowing in a discharge passage 350c can be increased.REFERENCE SIGNS LIST1 Flush toilet apparatus

[0141] 2 Flush toilet main body

[0142] 2a Water inlet

[0143] 4 Flush water tank device

[0144] 6 Bowl

[0145] 8 Water discharge trap pipe

[0146] 8a Inlet

[0147] 8b Ascending conduit

[0148] 8c Descending conduit

[0149] 8d Top portion

[0150] 10 Rim spout port

[0151] 12 Rim conduit

[0152] 14 Jet spout port

[0153] 16 Jet conduit

[0154] 16a Upstream side flow channel

[0155] 16b Bending flow channel

[0156] 16c Downstream side flow channel

[0157] 18 Waste receiving surface

[0158] 20 Rim

[0159] 21 Shelf

[0160] 22 Well portion

[0161] 24 Valve unit

[0162] 24a Electromagnetic valve for supplying water to tank

[0163] 24b Rim spout electromagnetic valve

[0164] 26 Flush water tank main body

[0165] 26a Projection

[0166] 26b Discharge passage

[0167] 26c Groove

[0168] 26d Seat surface

[0169] 28 Discharge valve

[0170] 28a Disk part

[0171] 28b Exhaust passage

[0172] 28c Contraction and merging suppression part (projection, guide part)

[0173] 28d Bead chain

[0174] 30 Base plate

[0175] 30a Discharge opening

[0176] 30b Cylindrical portion

[0177] 30c Upper surface concave portion

[0178] 30d Lower surface concave portion

[0179] 30e Discharge port

[0180] 32 Discharge valve driving mechanism

[0181] 34 O-ring

[0182] 36 Packing

[0183] 38 Bolt

[0184] 40 Flow guide part

[0185] 40a Cut

[0186] 100 Flush toilet apparatus

[0187] 102 Flush toilet main body

[0188] 102a Water inlet

[0189] 102b Water passageway

[0190] 104 Flush water tank device

[0191] 126 Flush water tank main body

[0192] 126b Discharge passage

[0193] 126d Seat surface

[0194] 128 Discharge valve

[0195] 128a Float portion

[0196] 128b Arm portion

[0197] 128c Pivot shaft

[0198] 128d Bead chain

[0199] 130 Overflow pipe

[0200] 130a Lower end opening

[0201] 130b Upper end opening

[0202] 132 Discharge valve driving mechanism

[0203] 226 Flush water tank main body

[0204] 226b Discharge passage

[0205] 226d Seat surface

[0206] 228 Discharge valve

[0207] 326 Flush water tank main body

[0208] 326b Discharge passage

[0209] 326d Seat surface

[0210] 328 Discharge valve

[0211] 328a Disk part

[0212] 328b Exhaust passage

[0213] 328d Bead chain

[0214] 350 Flush water tank main body

[0215] 350a Seat surface

[0216] 350b Side wall surface

[0217] 350c Discharge passage

[0218] 352 Encirclement wall surface

Claims

1. A flush toilet apparatus that performs flushing with flush water stored in a flush water tank device, the flush toilet apparatus comprising:a flush toilet main body that includes a bowl and a water inlet into which the flush water for flushing the bowl flows; anda flush water tank device that stores the flush water for flushing the bowl, whereinthe flush water tank device includes:a flush water tank main body that stores the flush water;a discharge port from which the flush water in the flush water tank main body is discharged to flow into the water inlet of the flush toilet main body;an annular seat surface provided to surround the discharge port;a discharge valve that is seated on and detached from the seat surface, so that the flush water is discharged and stopped from the flush water tank main body;an exhaust passage that communicates between a space below the seat surface and a space above a water surface of the flush water stored in the flush water tank main body in a state in which the discharge valve is seated on the seat surface; anda guide part provided in the discharge valve or in a bottom portion of the flush water tank main body to suppress contraction and merging of flows of flush water toward a center from a periphery of the seat surface when the flush water in the flush water tank main body is discharged.

2. The flush toilet apparatus according to claim 1, whereinthe guide part is a contraction and merging suppression part provided in the discharge valve, the discharge valve is configured to be pulled upward from the seat surface, and the exhaust passage is provided in the discharge valve and is configured to communicate between a lower end of the contraction and merging suppression part and a space above the water surface of the flush water stored in the flush water tank main body.

3. The flush toilet apparatus according to claim 2, whereinthe contraction and merging suppression part is a projection provided in a lower end of the discharge valve and extending downward with respect to the seat surface in a state in which the discharge valve is seated on the seat surface.

4. The flush toilet apparatus according to claim 2, whereina water passageway extending from the water inlet of the flush toilet main body is water-sealed by the flush water stored in the flush toilet main body, and an air layer is formed between the seat surface and a water seal surface in the water passageway.

5. The flush toilet apparatus according to claim 1, whereinthe flush water tank device further includes a flow guide part which is a wall surface provided outside of the seat surface to surround the seat surface.

6. The flush toilet apparatus according to claim 5, whereina water passageway extending from the water inlet of the flush toilet main body is water-sealed by the flush water stored in the flush toilet main body, a discharge passage in which a cross-sectional area of a flow channel decreases downward is formed between the seat surface and the discharge port, and in a vertical plane, straight lines that pass through an upper end of the flow guide part and are tangent to an inner wall surface of the discharge passage intersect below a water seal surface of the water passageway of the flush toilet main body.

7. A flush toilet apparatus that performs flushing with flush water stored in a flush water tank device, the flush toilet apparatus comprising:a flush toilet main body that includes a bowl and a water inlet into which the flush water for flushing the bowl flows; anda flush water tank device that stores the flush water for flushing the bowl, whereinthe flush water tank device includes:a flush water tank main body that stores the flush water;a discharge port from which the flush water in the flush water tank main body is discharged to flow into the water inlet of the flush toilet main body;an annular seat surface provided to surround the discharge port;a discharge valve that is seated on and detached from the seat surface, so that the flush water is discharged and stopped from the flush water tank main body; andan overflow pipe that communicates between a lower end opening that is opened in a space below the seat surface and an upper end opening that is opened on an upper side with respect to a water surface of the flush water stored in the flush water tank main body, whereina water passageway extending from the water inlet of the flush toilet main body is water-sealed by the flush water stored in the flush toilet main body, andthe discharge valve is configured to be detached from the seat surface by being turned about a pivot shaft provided on one end portion, and the lower end opening of the overflow pipe is provided on an opposite side of the pivot shaft.

8. The flush toilet apparatus according to claim 1, wherein the flush water tank main body includes a discharge passage formed to extend downward from a bottom surface, the guide part is a flow guide part that is provided in a bottom portion of the flush water tank main body and decreases a flow velocity of flush water toward a center of the discharge passage in the flush water tank main body, and the flow guide part is an encirclement wall surface provided outside of the seat surface to surround the seat surface.

9. The flush toilet apparatus according to claim 8, wherein the flow guide part has an upper end located above a tangent line in an inlet of the discharge passage in a vertical cross section.

10. The flush toilet apparatus according to claim 8, wherein the discharge valve is configured to be pulled upward from the seat surface, and in a state in which the discharge valve is pulled up to a highest position, a vertical distance from an upper end of the encirclement wall surface to the discharge valve is a half or more of a vertical distance from the seat surface to the discharge valve.

11. The flush toilet apparatus according to claim 8, wherein the encirclement wall surface surrounding the seat surface has cuts formed in portions of the encirclement wall surface.

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