JPH10295620A - Pump for dish washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump for dish washing machine with which the scroll shape of the casing is well maintained when the washing water is in circulation. SOLUTION: A pump for dish washing machine is composed of a casing 2 having a scroll shape when viewed on the plan, an impeller furnished inside the casing, and a motor capable of rotating in the regular and the reverse direction to turn the impeller. A ring-shaped passage 2b is provided between the peripheral edge of the impeller and the side wall of casing, and a suction hole 2d is formed in either end wall of casing in such a way as confronting the center opening of the impeller while a discharge hole 2e for circulation is furnished in the side wall of the casing. A discharge hole 2f for drainage is provided in either of the casing side walls in its part facing the ring-shaped passage, where a valve seat constituting the peripheral wall of the discharge hole 2f and a valve element 5 having a valve plate contacting with the valve seat are installed. The valve plate is attached by threads to the side wall of casing, where the thread fitting part is located upstream of the discharge hole for drainage about the water flowing direction within the ring-shaped passage at the time of the washing water circulating when the motor is rotating in the regular direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dishwasher pump.

[0002]

2. Description of the Related Art Japanese Unexamined Utility Model Publication No. 1-108264 has a casing in a scroll shape in plan view, an impeller provided in the casing, and a forward / reverse rotatable motor for driving the impeller to rotate. An annular flow path is formed between the outer peripheral edge of the casing and the casing side wall, a suction port is formed on one of the casing end walls facing the central opening of the impeller, and a circulation discharge port is formed on the casing side wall. A dishwasher pump in which a drainage outlet is formed on the casing side wall, a drain plate extending from the drainage outlet is hinged to a valve plate for opening and closing the drainage pipe, and a folded portion is formed at a free end of the valve plate. Is disclosed.

[0003] The dishwasher pump is disposed at the bottom of the dishwasher. In the above dishwasher pump,
At the time of washing water circulation in which the motor rotates forward, washing water flowing into the central opening of the impeller through the suction port is discharged from the outer peripheral portion of the impeller through the inter-blade flow path of the impeller, and flows through the annular flow path. It flows toward the discharge port for circulation. The valve plate closes the drain pipe due to the fluid force applied to the folded portion of the valve plate, and the washing water flowing in the annular flow path is discharged from the circulation outlet without flowing out from the drain outlet, and the dishwasher is washed. Reflux to the nozzle. At the time of washing water drainage in which the motor rotates in the reverse direction, the washing water discharged from the outer peripheral portion of the impeller flows in the annular flow path in a direction opposite to that during the washing water circulation. Fluid force applied to the folded portion of the valve plate rotates the valve plate to open the drain pipe, and the washing water flowing in the annular flow path flows into the drain pipe from the discharge outlet for drain and is discharged. The pump for a dishwasher disclosed in Japanese Utility Model Laid-Open No. 1-108264 has an advantage that a single pump has both a function of a washing water circulation pump and a function of a washing water drainage pump.

[0004]

Problems to be Solved by the Invention
In the dishwasher pump disclosed in No. 4, a valve plate is hinged to a drain pipe extending from a drain outlet formed in a casing side wall, so that the motor rotates forward and the valve plate is drained. When the washing water is circulated, a portion from the drain outlet of the drain pipe to the valve plate is added to the internal space of the casing,
There is a problem that the scroll shape of the casing is broken due to the presence of the added portion, and the pump performance is reduced. The present invention has been made in view of the above problems,
A dishwasher pump having a scroll-shaped casing in plan view and having both a function of a pump for washing water circulation and a function of a pump for washing water drainage, and for a dishwasher in which the casing scroll shape is maintained during washing water circulation. It is intended to provide a pump. .

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a casing having a scroll shape in plan view, an impeller disposed in the casing, and a forward / reverse rotation for driving the impeller to rotate. Possible motor, an annular flow path is formed between the outer peripheral edge of the impeller and the casing side wall,
A suction port is formed on one of the casing end walls to face the central opening of the impeller, a circulation discharge port is formed on the casing side wall, and a portion facing one of the annular flow paths on the casing end wall. A valve body having a valve seat forming a surrounding wall of the drainage discharge port and a valve plate abutting on the valve seat is attached to a casing end wall in which a drainage discharge port is formed, and the drainage discharge port is formed. Is hinged to the casing end wall, and the hinge portion of the valve plate is positioned upstream of the discharge port for drainage with respect to the flow direction in the annular flow path during the circulation of the washing water in which the motor rotates forward, and the free end of the valve plate is The present invention provides a dishwasher pump characterized in that the pump is positioned downstream of a discharge port for drainage with respect to the direction of water flow in an annular flow path during circulation of washing water in which a motor rotates forward.

In the dishwasher pump according to the present invention, when the washing water circulates with the motor rotating forward, the washing water flowing into the central opening of the impeller through the suction port passes through the inter-blade flow path of the impeller. The water is discharged from the outer periphery of the impeller and flows toward the circulation discharge port in the annular flow path. The hinge portion of the valve plate is positioned upstream of the discharge outlet in the flow direction of the annular flow path during the circulation of the wash water, and the free end of the valve plate is drained in the flow direction of the flow flow in the annular flow path of the wash water. Because it is positioned on the downstream side from the discharge port for use, the valve plate rotates downstream around the hinged portion and abuts on the valve seat by the fluid force applied to the valve plate from the washing water flowing through the annular flow path, Close drainage outlet. As a result, the washing water flowing in the annular flow path is discharged from the circulation outlet without flowing out from the drain outlet,
Reflux to the washing nozzle of the dishwasher. At the time of washing water drainage in which the motor rotates in the reverse direction, the washing water discharged from the outer peripheral portion of the impeller flows in the annular flow path in a direction opposite to that during the washing water circulation.
At the time of washing water drainage, the hinge portion of the valve plate is located downstream of the drainage outlet in the flowing direction of the annular flow path, and the free end of the valve plate is located closer to the flowing direction of the annular flow path than the drainage outlet. Since it is on the upstream side, the valve plate pivots downstream around the hinged portion and separates from the valve seat by the fluid force applied to the valve plate from the washing water flowing through the annular flow path, thereby opening the drain outlet. As a result, the washing water flowing in the annular flow path is discharged from the drain outlet and discharged from the dishwasher.

The dishwasher pump according to the present invention has both a function of a washing water circulation pump and a function of a washing water drainage pump. In the dishwasher pump according to the present invention, since the valve plate covering the drainage discharge port formed on the end wall of the casing is hinged to the end wall of the casing, the motor rotates forward to rotate the valve plate. No space is added to the internal space of the casing during the circulation of the washing water for closing the discharge port for drainage. As a result, the scroll shape of the casing is maintained during the circulation of the washing water, and the pump performance is maintained in a good state.

Further, in the present invention, there is provided a casing having a scroll shape in a plan view, an impeller disposed in the casing, and a forward / reverse rotatable motor for rotating and driving the impeller. An annular flow path is formed between the casing and the casing side wall, a suction port is formed on one of the casing end walls facing the center opening of the impeller, a circulation outlet is formed on the casing side wall, and a casing side wall is formed on the casing side wall. A discharge port for drainage is formed, a valve body having a valve seat constituting a surrounding wall of the discharge port for drainage on a casing side wall and a valve plate abutting on the valve seat is attached, the valve plate is hinged to the casing side wall, and a valve is provided. The plate covers only the discharge outlet for drainage, and the hinged portion of the valve plate is positioned upstream of the discharge outlet for drainage with respect to the direction of water flow in the annular flow path during the circulation of wash water in which the motor rotates forward, and the free end of the valve Is forward rotating washing water Providing dishwasher pump, characterized in that it is positioned downstream of the water discharge discharge port with respect to running water direction of the annular flow path when the ring.

In the dishwasher pump according to the present invention, when the washing water circulates in the forward rotation of the motor, the washing water flowing into the central opening of the impeller through the suction port passes through the inter-blade flow path of the impeller. The water is discharged from the outer periphery of the impeller and flows toward the circulation discharge port in the annular flow path. The hinge portion of the valve plate is positioned upstream of the discharge outlet in the flow direction of the annular flow path during the circulation of the wash water, and the free end of the valve plate is drained in the flow direction of the flow flow in the annular flow path of the wash water. Because it is positioned on the downstream side from the discharge port for use, the valve plate rotates downstream around the hinged portion and abuts on the valve seat by the fluid force applied to the valve plate from the washing water flowing through the annular flow path, Close drainage outlet. As a result, the washing water flowing in the annular flow path is discharged from the circulation outlet without flowing out from the drain outlet,
Reflux to the washing nozzle of the dishwasher. At the time of washing water drainage in which the motor rotates in the reverse direction, the washing water discharged from the outer peripheral portion of the impeller flows in the annular flow path in a direction opposite to that during the washing water circulation.
At the time of washing water drainage, the hinge portion of the valve plate is located downstream of the drainage outlet in the flowing direction of the annular flow path, and the free end of the valve plate is located closer to the flowing direction of the annular flow path than the drainage outlet. Since it is on the upstream side, the valve plate pivots downstream around the hinged portion and separates from the valve seat by the fluid force applied to the valve plate from the washing water flowing through the annular flow path, thereby opening the drain outlet. As a result, the washing water flowing in the annular flow path is discharged from the drain outlet and discharged from the dishwasher.

The dishwasher pump according to the present invention has both a function of a washing water circulation pump and a function of a washing water drainage pump. In the dishwasher pump according to the present invention, since the valve plate covering the drainage outlet formed on the side wall of the casing is hinged to the side wall of the casing, the motor rotates forward to rotate the valve plate for drainage. When the washing water is circulated to close the discharge port, no space is added to the internal space of the casing. As a result, the scroll shape of the casing is maintained during the circulation of the washing water, and the pump performance is maintained in a good state.

In a preferred aspect of the present invention, a projection protruding toward the inside of the annular flow passage is formed at the free end of the valve plate. By forming a projection at the free end of the valve plate that projects into the inside of the annular flow path, the fluid force applied to the valve plate from the washing water flowing in the annular flow path increases, and the opening and closing operation of the valve plate is accelerated. As a result, the closing of the discharge port for drainage by the valve plate is more complete.

In a preferred embodiment of the present invention, the discharge port for drainage is substantially 90 circumferentially wider than the discharge port for circulation with respect to the direction of flowing water in the annular flow path during the circulation of washing water in which the motor rotates forward.
° The dishwasher pump, which is arranged upstream, is used with the drainage outlet facing downward. The discharge outlet for drainage is disposed approximately 90 ° in the circumferential direction upstream of the discharge outlet for circulation with respect to the direction of water flow in the annular flow path during the circulation of washing water in which the motor rotates forward, and the pump for the dishwasher is discharged for drainage. When the washing water is circulated, the washing water discharged upward from the circulation outlet can be smoothly guided to the upper washing nozzle when the washing water is circulated. The cleaning water is discharged from the discharge port to prevent air from being sucked in, and it is possible to prevent a decrease in drainage capacity due to air suction.

In a preferred aspect of the present invention, a drainage hose is connected to the drainage outlet, a drainage return hole is formed in a side wall of the drainage hose, and a portion downstream of the drainage return hole of the drainage hose is raised. ing. A drain leak hole is formed in the side wall of the drain hose connected to the drain outlet, and a part that is located downstream from the leak return hole of the drain hose is set up, so that washing that leaks slightly from the drain outlet during washing water circulation Water can be reliably returned to the dishwasher from the leak return hole.

In a preferred aspect of the present invention, a bulging portion is formed on the side wall of the casing, and a discharge port for drainage is formed on a portion of the end wall of the casing facing the bulging portion. By forming a bulging portion on the casing side wall and forming a discharge port for drainage at a portion of the casing end wall facing the bulging portion,
The position of the discharge outlet for drainage can be lowered, so that suction of air during drainage of washing water can be prevented, and a decrease in drainage capacity due to suction of air during drainage of washing water can be prevented.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described. As shown in FIGS. 1 and 2, a dishwasher pump 1 is provided at the bottom of the dishwasher A. Dishwasher pump 1
Includes a casing 2 having a scroll shape in a plan view, an impeller 3 provided in the casing 2, and a forward / reverse rotatable motor 4 for driving the impeller 3 to rotate. An annular flow path 2 is provided between the outer peripheral edge of the impeller 3 and the side wall 2a of the casing 2.
b is formed. A suction port 2 d is formed in the casing end wall 2 c on the side remote from the motor 4 so as to face the central opening 3 a of the impeller 3. A circulation outlet 2e is formed in the casing side wall 2a. A discharge port 2f for drainage is formed in a portion of the casing end wall 2c that is separated from the motor 4 and faces the annular flow path 2b. The discharge port 2f for drainage is disposed at a position approximately 90 ° upstream of the discharge port 2e for circulation in the circumferential direction with respect to the direction of flowing water in the annular flow path 2b at the time of circulation of the washing water in which the motor indicated by the arrow in FIG. ing.
The dishwasher pump 1 is disposed horizontally with the circulation outlet 2e facing upward and the drain outlet 2f facing downward. A circulating water hose (not shown) connected to the circulation outlet 2e extends upward and is connected to a cleaning nozzle (not shown).

As shown in FIGS. 2 and 3, the discharge port 2f for drainage is provided.
The drainage outlet 2f is formed on the casing end wall 2c in which
A valve body 5 having a valve seat 5a that constitutes the surrounding wall and a valve plate 5b that comes into contact with the valve seat 5a is attached. Valve plate 5b
Is hinged to the casing end wall 2c. The hinged portion of the valve plate 5b is positioned upstream of the discharge outlet 2f with respect to the direction of water flow in the annular flow path 2b during the washing water circulation in which the motor shown by arrows in FIGS. The free end of 5b is positioned downstream of the discharge outlet 2f with respect to the direction of flowing water in the annular flow path 2b during the circulation of the washing water in which the motor shown by the arrow in FIGS. As shown in FIG. 3, a protruding portion 5b 'protruding toward the inside of the annular flow passage 2b is formed at the free end of the valve plate 5b.

As shown in FIG. 1, a drain hose 6 is connected to the drain outlet 2f, and extends out of the dishwasher A. A drainage return hole 6a is formed in a side wall of a portion of the drain hose 6 extending in the dishwasher A. A portion 6b on the downstream side of the water return hole 6a of the drain hose 6 is raised.

The operation of the dishwasher pump 1 will be described below. In the dishwasher pump 1, when the motor 4 and, consequently, the impeller 3 rotates forward in the direction indicated by the white arrow in FIG. 2, the washing water flowing into the central opening 3a of the impeller 3 through the suction port 2d. Water is discharged from the outer peripheral portion of the impeller 3 through the blade-to-blade flow path of the impeller 3, and flows in the annular flow path 2b toward the circulation discharge port 2e. The hinged portion of the valve plate 5b is positioned upstream of the discharge outlet 2f with respect to the flowing direction of the annular flow path 2b during the circulation of the washing water indicated by the arrow in FIGS. The free end is shown in Figs. 2 and 3
(A) is positioned downstream of the discharge port 2f for drainage with respect to the direction of water flow in the annular flow path 2b during the circulation of the wash water indicated by the arrow in FIG. Due to the applied fluid force, the valve plate 5b pivots downstream around the hinged portion and abuts on the valve seat 5a, and the discharge port 2 for drainage
Close f. As a result, the washing water flowing in the annular flow path 2b is discharged upward from the circulation discharge port 2e without flowing out from the drain discharge port 2f, and is disposed above the pump 1 through a circulating water hose (not shown). It returns to the washing nozzle (not shown) of the dishwasher A that has been used.

At the time of washing water drainage in which the motor 4 and thus the impeller 3 rotates in the reverse direction in the direction indicated by the double outline arrow in FIG. 2, the washing water discharged from the outer periphery of the impeller 3 cleans the inside of the annular flow path 2b. It flows in the opposite direction to the water circulation. At the time of drainage of the washing water, the hinged portion of the valve plate 5b is located downstream of the discharge outlet 2f with respect to the flowing direction of the annular flow path 2b indicated by a double arrow in FIGS. 2 and 3
In (b), since it is on the upstream side of the discharge port 2f for drainage with respect to the direction of flowing water in the annular flow path 2b indicated by the double arrow, by the fluid force applied to the valve plate 5b from the washing water flowing in the annular flow path 2b. The valve plate 5b rotates downstream around the hinged portion and the valve seat 5
a, and discharge opening 2f for drainage is opened. As a result,
The washing water flowing in the annular flow passage 2b is discharged from the drainage discharge port 2f and discharged from the dishwasher A. As can be seen from FIG. 2, the washing water in the annular flow path 2b flows away from the circulation outlet 2e at the time of washing water drainage. There is no possibility that a large amount of cleaning water is discharged from the discharge port 2e.

The dishwasher pump 1 has both a function of a washing water circulation pump and a function of a washing water drainage pump.
In the dishwasher pump 1, the valve plate 5 b that covers the discharge outlet 2 f formed in the end wall 2 c of the casing 2 is hinged to the end wall 2 c of the casing 2, so that the motor 4
When the washing water circulates when the valve plate 5b rotates forward and the valve plate 5b closes the discharge port 2f for drainage, no space is added to the internal space of the casing 2. As a result, the casing 2
Is maintained, and the pump performance is maintained in a good state.

Since the projection 5b 'is formed at the free end of the valve plate 5b so as to protrude toward the inside of the annular flow path 2b, the annular flow path 2b is formed as compared with the case where the projection 5b' is not formed.
Fluid force applied to the valve plate 5b from the cleaning water flowing inside increases. As a result, compared to the case where the projection 5b 'is not formed, the opening and closing operation of the valve plate 5b is speeded up, and the closing of the discharge port 2f for drainage by the valve plate 5b is more complete.

The discharge port 2f for drainage is substantially 90 ° in the circumferential direction from the discharge port 2e for circulation with respect to the direction of water flow in the annular flow path 2b during the circulation of the washing water in which the motor 4 shown in FIG.
The dishwasher pump 1, which is disposed on the upstream side, is used with the circulation outlet 2e facing upward and the drain outlet 2f facing downward. The cleaning water discharged upward from the outlet 2e can be smoothly guided to the upper cleaning nozzle (not shown), and when the cleaning water is drained, the cleaning water is discharged from the drain outlet 2f located at a lower position to prevent the suction of air. In addition, it is possible to prevent a decrease in drainage capacity due to suction of air.

A drain hose 6 is connected to the drain outlet 2f, and a drain return hole 6a is formed in a side wall of a portion of the drain hose 6 extending in the dishwasher A. The washing water slightly leaking from the outlet 2f returns to the dishwasher A through the leak return hole 6a, and is effectively used as washing water. A portion 6b on the downstream side of the leak return hole 6a of the drain hose 6 is raised, and the rising portion blocks the water flow in the drain hose 6, so that a slight leak from the drain outlet 2f during circulation of the washing water. The washing water that flows out can be reliably returned to the dishwasher A through the leak return hole 6a.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. As shown in FIG. 4, a valve having a drain port 12f formed in a side wall 2a of the casing 2 and having a valve seat 15a forming an enclosure of the drain port 12f and a valve plate 15b abutting on the valve seat 15a. The body 15 may be attached to the side wall 2a of the casing 2. Also in the configuration of FIG. 4, there is no space added to the internal space of the casing 2 during the circulation of the washing water in which the motor rotates forward and the valve plate 15b closes the discharge port 12f for drainage. As a result, the scroll shape of the casing 2 is maintained during the circulation of the washing water, and the pump performance is maintained in a good state.

As shown in FIG. 5, the side wall 2 of the casing 2
The portion 2a 'adjacent to the drainage discharge port 2f of a may be bulged radially outward. By forming the discharge outlet 2f at a portion of the end wall 2c of the casing 2 facing the bulging portion, the arrangement position of the discharge outlet 2f can be lowered, and the air is sucked when the washing water is drained. Can be more reliably prevented, and a decrease in drainage capacity due to suction of air at the time of drainage of washing water can be more reliably prevented. If the bulging portion is formed in a gentle shape and the depth of the bulging portion is regulated within an appropriate range, the shape of the casing 2 in plan view does not significantly deviate from the scroll shape, and the pump performance is maintained in a good state.

[0026]

In the dishwasher pump according to the present invention, since the valve plate for covering the discharge outlet formed on the end wall of the casing is hinged to the end wall of the casing, the motor rotates forward. When the washing water is circulated so that the valve plate closes the discharge port for drainage, no space is added to the internal space of the casing. As a result, the scroll shape of the casing is maintained during the circulation of the washing water, and the pump performance is maintained in a good state.

In the dishwasher pump according to the present invention, the valve plate covering the discharge outlet formed on the side wall of the casing is hinged to the side wall of the casing. When the washing water is circulated to close the drain outlet, no space is added to the internal space of the casing. As a result, the scroll shape of the casing is maintained during the circulation of the washing water, and the pump performance is maintained in a good state.

By forming a projection protruding toward the inside of the annular flow passage at the free end of the valve plate, the fluid force applied to the valve plate from the washing water flowing through the annular flow passage increases, and the opening and closing operation of the valve plate increases. It is quicker and the closure of the drain outlet by the valve plate is more complete.

The discharge port for drainage is disposed at approximately 90 ° in the circumferential direction upstream of the discharge port for circulation with respect to the direction of water flow in the annular flow path during circulation of the washing water in which the motor rotates forward, and the pump for the dishwasher is provided. By placing the drainage outlet horizontally downward, the washing water discharged upward from the circulation outlet can be smoothly guided to the upper washing nozzle when the washing water is circulated, and the washing water is at a low position when the washing water is drained. The cleaning water is discharged from the discharge outlet for drainage to prevent suction of air, thereby preventing a reduction in drainage capacity due to suction of air.

A drainage return hole is formed in the side wall of the drainage hose connected to the drainage outlet, and a portion located downstream of the drainage return hole of the drainage hose is set up, so that the drainage outlet slightly extends from the drainage outlet during washing water circulation. The leaking washing water can be reliably returned to the dishwasher from the leak return hole.

By forming a swelling portion on the casing side wall and forming a drainage outlet at a portion of the casing end wall facing the swelling portion, the arrangement position of the drainage outlet can be lowered. It is possible to prevent the suction of air when draining the washing water, and it is possible to prevent a decrease in drainage capacity due to the suction of air when draining the washing water.

[Brief description of the drawings]

FIG. 1 is a side view of a dishwasher pump according to an embodiment of the present invention.

FIG. 2 is a view as viewed in the direction of arrows aa in FIG. 1;

FIG. 3 is a view taken in the direction of arrows bb in FIG. 2; (A) is a view on arrow bb in FIG. 2 at the time of washing water circulation, and (b) is a view on arrow bb of FIG. 2 at the time of washing water drainage.

FIG. 4 is a view corresponding to FIG. 2 of a modified example of the dishwasher pump according to the embodiment of the present invention, as viewed in the direction of arrows.

FIG. 5 is a view corresponding to FIG. 2 of a modified example of the dishwasher pump according to the embodiment of the present invention, as viewed in the direction of arrows.

[Explanation of symbols]

 A Dishwasher 1 Dishwasher pump 2 Casing 2a Side wall 2b Annular flow path 2c End wall 2d Inlet 2e Circulating outlet 2f, 12f Drain outlet 3 Impeller 4 Pump 5, 15 Valve 6 Drain hose 6a Water leakage return hole

Claims (6)

[Claims] A casing having a scroll shape in plan view;
An impeller disposed in the casing, and a forward / reverse rotatable motor that rotationally drives the impeller, an annular flow path is formed between an outer peripheral edge of the impeller and a casing side wall, and a casing end wall is formed. A suction port is formed on one of the impellers so as to face the central opening of the impeller, a circulation discharge port is formed on the casing side wall, and a drainage discharge port is formed on a portion of the casing end wall facing one of the annular flow paths. Is formed, a valve body having a valve seat constituting a surrounding wall of the discharge port for drainage and a valve plate abutting on the valve seat is attached to a casing end wall in which the discharge port for drainage is formed,
The valve plate is hinged to the end wall of the casing, and the hinged portion of the valve plate is positioned upstream of the discharge outlet for drainage with respect to the flowing direction of the annular flow path during the circulation of the washing water in which the motor rotates forward, and A pump for a dishwasher, wherein the free end is positioned downstream of a discharge port for drainage with respect to a flow direction in an annular flow path in a circulation of washing water in which a motor rotates forward. 2. A casing having a scroll shape in a plan view,
An impeller disposed in the casing, and a forward / reverse rotatable motor that rotationally drives the impeller, an annular flow path is formed between an outer peripheral edge of the impeller and a casing side wall, and a casing end wall is formed. A suction port is formed on one of the impellers facing the central opening of the impeller, a discharge port for circulation is formed on the casing side wall, a discharge port for drainage is formed on the casing side wall, and a surrounding wall of the discharge port for drainage is formed on the casing side wall. A valve body having a valve seat and a valve plate abutting on the valve seat is attached, the valve plate is hinged to the casing side wall, the valve plate covers only the discharge outlet for drainage, and the hinged portion of the valve plate is The position of the free end of the valve plate is set at the free end of the valve plate with respect to the direction of flowing water in the annular flow path during the washing water circulation in which the motor rotates forward, and the free end of the valve plate flows in the annular flow path during the washing water circulation in which the motor rotates forward. Downstream from drainage outlet in direction Dishwasher pump, characterized in that it is positioned. 3. The dishwasher pump according to claim 1, wherein a projection protruding toward the inside of the annular flow path is formed at a free end of the valve plate. 4. The discharge port for drainage is disposed approximately 90 ° upstream in the circumferential direction of the discharge port for circulation with respect to the direction of water flow in the annular flow path during circulation of the washing water in which the motor rotates forward, and the discharge port for drainage. The dishwasher pump according to any one of claims 1 to 3, wherein the pump is used by being placed sideways downward. 5. A drainage hose is connected to the drainage outlet,
The dishwasher according to any one of claims 1 to 4, wherein a drainage return hole is formed in a side wall of the drainage hose, and a portion downstream of the drainage return hole of the drainage hose is raised. Machine pump. 6. The dishwasher according to claim 1, wherein a bulging portion is formed in a casing side wall, and a discharge hole for drainage is formed in a portion of the casing end wall facing the bulging portion. For pumps.