Washer pump and filter used for washer pump

A washer pump includes a case partitioned into a motor chamber, which accommodates an armature rotated when it is electrically energized, and partitioned into a pump chamber, which accommodates an impeller rotated being coupled to an armature shaft of the armature, wherein washing liquid is sucked into the pump chamber from a liquid suction port, which is communicated with the pump chamber, by the rotation of the impeller, and the washing liquid is discharged from a liquid discharge port which is communicated with the pump chamber, and the washer pump is characterized in that: a ventilation hole is provided on a partition wall to partition the pump chamber and the liquid suction port, a filter for filtering the washing liquid is detachably attached to the liquid suction port, an air passage is provided in the filter, and the air passage is communicated with the ventilation hole.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a washer pump for sucking washing liquid stored in a washer tank and injecting it from a nozzle. The present invention also relates to a filter used for the washer pump.

2. Related Art

This type washer pump is disclosed in Japanese Utility Model Publication No. H02-60659U shown inFIGS. 13 and 14. As shown inFIG. 13, this washer pump1is attached via the cylindrical communicating member6, the outer circumference of which is engaged with the liquid discharge port5bformed on the side wall5aof the washer tank5. The pump case2of this washer pump1includes: a motor chamber2aaccommodating the armature3rotating when electricity is supplied to it; and a pump chamber2baccommodating the impeller4rotating being coupled to the armature shaft3aof the armature3. The cylindrical liquid suction port2ccommunicating with the pump chamber2bis inserted into the inner circumference of the communicating member6. As shown inFIG. 14, the filter7for filtering washing liquid W is arranged in the communicating member6.

When a predetermined intensity of electric power is supplied from the connector2efor supplying electric power to the washer pump1via a switch not shown in the drawing, the armature3is rotated and the impeller4is rotated in the pump chamber2b. When the impeller4is rotated, washing liquid W stored in the washer tank5is sucked from the liquid suction port2cinto the pump chamber2b. At the same time, washing liquid W is discharged from the liquid discharge port2dcommunicated with the pump chamber2b. Washing liquid W, which has been discharged from the liquid discharge port2d, is supplied to the nozzle9flowing in the liquid supply pipe8and injected from the nozzle9to a washing face not shown in the drawing.

While washing liquid W is being sucked from the liquid discharge port5bof the washer tank5into the liquid suction port2cof the washer pump1via the communicating member6, foreign objects such as dust are removed and filtered by the mesh-like filtering portion7aof the filter7provided in the communicating member6. Therefore, no foreign objects are sucked into the pump chamber2bof the washer pump1. Due to the foregoing, the occurrence of damage of the impeller in the pump chamber2bcaused by the mixed foreign objects can be prevented. Also, the occurrence of blinding of the nozzle9can be prevented.

However, in the case of the aforementioned conventional washer pump1, a centrifugal type washer pump is adopted, the suction pressure of which is so low that the sucking operation cannot be performed. Therefore, when the washer pump1is operated, it is impossible for the centrifugal type washer pump to let air out of the pump chamber2bso as to reduce the pressure in the pump chamber2bto be negative. Therefore, the impeller4is idly rotated, and it is impossible to discharge washing liquid W from the liquid discharge port2dof the pump chamber2b. Especially in the case where the mesh-like filtering portion7ais arranged in the communicating member6or a check valve is arranged in the liquid supply pipe8for communicating the pump chamber2bwith the nozzle9is arranged, when washing liquid W is poured into the washer tank5, a water film formed on the filter7by the action of surface tension can not be torn away even when the washer pump1is operated, and the impeller4is idly rotated and washing liquid W can not be discharged from the liquid discharge port2dof the pump chamber2b. In the conventional washer pump, this phenomenon remarkably appears.

SUMMARY OF THE INVENTION

The present invention has been accomplished to solve the above problems. It is an object of the present invention to provide a washer pump and a filter, which is used for the washer pump, characterized in that: even if a water film is formed on the filter, the water film on the filter is torn away by letting air out from a pump chamber so as to make the pressure in the pump chamber negative and washing liquid is sucked into the pump chamber and positively discharged out from a liquid discharge port.

(1) The invention provides a washer pump comprising:

a case which is partitioned into a motor chamber and a pump chamber;

an armature accommodated in the motor chamber, the armature having an armature shaft rotatable when the armature is electrically energized;

an impeller accommodated in the pump chamber and coupled to the armature shaft so as to be rotatable;

a liquid suction port communicating with the pump chamber from which washing liquid is sucked into the pump chamber by a rotation of the impeller;

a liquid discharge port communicating with the pump chamber from which the washing liquid is discharged; and

a filter detachably attached in the liquid suction port for filtering the washing liquid,

wherein a ventilation hole is formed on a partition wall between the pump chamber and the liquid suction port, so that an air passage communicating with the ventilation hole is provided in the filter.

(2) The invention provides a washer pump, wherein the filter is provided with a filter body having a cylindrical circumferential wall and a bottom wall, each of the bottom wall and the circumferential wall of the filter body being formed with mesh-like filtering portions, and

a part of the circumferential wall is formed into a duct portion functioning as an air passage extending in the longitudinal direction of the filter.

(3) The invention provides a washer pump, wherein the duct portion is extended from an opening side of the filter so as to horizontally protrude from the bottom wall, and a cutout portion formed on a bottom face of the duct portion at a rear side thereof is made to closely come into contact with an attachment portion having flat faces in a stepped manner in the liquid suction port.

In the washer pump of the invention, even when a water film is formed on the filter, air is let out from the pump chamber via the air passage, and the pressure in the pump chamber is reduced to be negative. Therefore, the water film on the filter is torn away. Due to the foregoing, washing liquid is sucked into the pump chamber and positively discharged out from the liquid discharge port.

(4) Further, the invention provides a filter adapted to be installed in a washer pump including a case partitioned into a motor chamber which accommodates an armature having an armature shaft that is rotatable when the armature is electrically energized, and a pump chamber which accommodates an impeller that is coupled to the armature shaft of the armature so as to be rotatable, wherein washing liquid is sucked into the pump chamber from a liquid suction port, which is communicated with the pump chamber by the rotation of the impeller, and the washing liquid is discharged from a liquid discharge port which is communicated with the pump chamber;

wherein a filter body for filtering the washing liquid is detachably attached to the liquid suction port, an air passage is provided in the filter body, so that the air passage is communicated with a ventilation hole provided on a partition wall for partitioning the pump chamber and the liquid suction port.

(5) The present invention provides a filter used for a washer pump, wherein the filter body includes a substantially cylindrical circumferential wall and a bottom wall, each of the circumferential wall and the bottom wall being formed into a mesh-like filtering portion, and

a part of the circumferential wall is formed into a duct portion functioning as an air passage extending in the longitudinal direction of the filter.

(6) The present invention provides a filter used for a washer pump, wherein the duct portion is extended from an opening side of the filter so as to horizontally protrude from the bottom wall, and a cutout portion formed on a bottom face of the duct portion at a rear side thereof is made to closely come into contact with an attachment portion having flat faces in a stepped manner in the liquid suction port.

According to the filter of the invention, even when a water film is formed on the filter body, air is let out from the pump chamber in the washer pump to the outside of the pump chamber via the ventilation hole and the air passage. Therefore, the pump chamber is set into a state of negative pressure, and the water film formed on the filter body is torn away. Due to the foregoing, washing liquid is sucked from the pump chamber and positively discharged out from the liquid discharge port.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, an embodiment of the present invention will be explained below.

FIG. 1is a sectional view taken on line A-A inFIG. 3showing a washer pump of an embodiment of the present invention,FIG. 2is a sectional view taken on line B-B inFIG. 3,FIG. 3is a bottom view of the washer pump,FIG. 4is a sectional view taken on line C-C inFIG. 2,FIG. 5is a longitudinal sectional view of a liquid sucking portion of the washer pump,FIG. 6is a perspective view of the filter used for the washer pump,FIG. 7is a front view of the filter,FIG. 8is a rear view of the filter,FIG. 9is a plan view of the filter,FIG. 10is a side view of the filter,FIG. 11is a bottom view of the filter, andFIG. 12is a schematic illustration showing a state in which the washer pump is attached.

As shown inFIGS. 1,2and12, the washer pump10is attached via the cylindrical communicating member6made of synthetic resin, the outer circumference of which is engaged with the liquid discharge port5bformed on the side wall5aof the washer tank5made of synthetic resin. The case11of the washer pump10includes: a motor chamber11A, which accommodates an armature20rotated when it is electrically energized; and a pump chamber11B, which accommodates an impeller22rotated being coupled to an armature shaft21of the armature20. Washing liquid W is sucked into the pump chamber11B from a liquid suction port16, which is communicated with the pump chamber11B, by the rotation of the impeller22, and washing liquid W is discharged from a liquid discharge port18which is communicated with the pump chamber11B. Washing liquid W discharged from the liquid discharge port18is supplied to a pair of nozzles9,9when it flows in the liquid supply pipe8and injected to a washing face not shown from the pair of nozzles9,9.

As shown inFIGS. 1 and 2, the case11includes: a cylindrical pump case12made of synthetic resin forming the motor chamber11A inside the peripheral wall12a, the upper face of which is open; a pump cover13made of synthetic resin, the cross section of which is a substantial U-shape, fixed to the outer circumferential portion12dof the bottom wall (partition wall) of the pump case12, for example, by means of welding, the pump chamber11B being formed inside the pump cover13; and a motor cover14made of synthetic resin engaged with the inner circumference of the opening portion12bof the pump case12. The connector15for supplying electric power made of synthetic resin is engaged with the outer circumference of the opening portion12bof the pump case12.

On the inner circumferential face of the circumferential wall12aof the pump case12, the cylindrical yoke23made of metal is fixed. On the inner circumferential face of this yoke23, the magnet24is fixed, for example, by fixing means such as a spring or additive. Between the bearing25engaged with the spherical recess portion14aat the center of the motor cover14and the bearing26engaged with the spherical inner circumferential face of the cylindrical portion12eat the center of the bottom wall12cof the pump case12, the upper end portion21aand the lower portion21cof the armature shaft21are respectively pivotally supported. A portion between the cylindrical portion12eat the center of the bottom wall12cof the pump case12and the lower portion21cof the armature shaft21is sealed by the annular seal body27. The motor chamber11A is water-tightly kept from the pump chamber11B by this seal body27.

The armature20is attached at a position opposed to the magnet24of the armature shaft21. This armature20includes: an armature core20afixed at the substantial center of the armature shaft21in the axial direction, having the coil winding portion20b, the number of slots of which is predetermined; and an armature coil20cwhich is wound round the coil winding portion20bof the armature coil20a.

The commutator28is fixed to the upper portion21bof the armature shaft21. This commutator28is provided with the commutator pieces28a, the number of which is the same as that of the coil winding portion20bof the armature core20a. Each commutator piece28aand the armature coil20care electrically connected with each other.

At a position on the motor cover14opposed to the commutator28, a pair of brush holders14b,14bare fixed. The brush29is attached to each brush holder14b. Each brush29is electrically connected with a washer circuit not shown via a pair of terminals15b,15bof the connector15for supplying electric power. When a washer switch not shown is turned on, an electric current flows to the armature20via the pair of terminals15b,15b, which extend into the connector attaching portion15aof the connector15for supplying electric power, and via each brush29and the commutator piece28a. Therefore, the armature shaft is normally rotated.

The cylindrical portion22aof the impeller22is combined with the lower end portion21dof the armature shaft21in such a manner that the cylindrical portion22aof the impeller22can not be relatively rotated in the circumferential direction with respect to the armature shaft21but can be slid in the axial direction. On the outer circumference of this cylindrical portion22a, there are provided a plurality of blades22bin the radial direction at regular intervals in such a manner that the plurality of blades22bprotrude from the outer circumference being integrated into one body.

As shown inFIGS. 1,5and12, on the bottom wall12cof the circumferential wall12aof the pump case12, there is provided a cylindrical liquid suction port16which protrudes from the bottom wall12cbeing integrated into one body. When this cylindrical liquid suction port16is inserted into the inner circumference of the cylindrical communicating member6of the washer tank5, the washer pump10can be attached to the washer tank5. The liquid suction port16is communicated with the pump chamber11B via the hole-shaped liquid introducing portion17formed at the center of the bottom wall12c. Further, as shown inFIGS. 1 and 5, in the periphery (on the circumferential wall12aside) of the outer circumferential edge of the bottom wall12c, which is a partition wall to partition the pump chamber11B and the motor chamber11A, the ventilation hole12f, which is a hole for letting air out, is formed so that it penetrates in the axial direction (the upward and downward direction). The liquid suction port16and the pump chamber11B are also communicated with each other by this ventilation hole12f.

As shown inFIGS. 2 and 4, at the central portion in the axial direction (the upward and the downward direction) of the bottom wall12c, which is a partition wall to partition the motor chamber11A and the pump chamber11B, there are provided a plurality of chambers19which are arranged in the circumferential direction at regular intervals. In this embodiment, there are provided a pair of chambers19,19which are arranged at positions symmetrical to each other in the circumferential direction. That is, the recess portions12g,12gare respectively formed at positions symmetrical to each other in the circumferential direction toward the inside from the central portion in the axial direction of the outer circumferential edge of the outer circumference12dof the bottom wall12c. By the pair of recess portions12g,12gand the circumferential wall13aof the pump cover13, the chambers19,19are respectively formed. As shown inFIGS. 2 and 4, on the bottom wall12cof the pump case12inside the upper face19aof each chamber19, the inside ventilation hole12hcommunicating with the motor chamber11A is formed so that it penetrates in the axial direction (the upward and the downward direction). As shown inFIGS. 2 and 3, in the outer circumferential portion of the bottom wall13cof the pump cover13, which is located at a position lower in the axial direction than the outer circumferential edge of the bottom wall12cof the lower face19bof each chamber19, there are provided a plurality of outside ventilation holes13hcommunicating with the outside air which are arranged in the circumferential direction at regular intervals.

Further, as shown inFIG. 2, on the lower face19bof each chamber19, there is provided a conical inclination face in such a manner that a distance of the conical inclination face from the upper face19aof the chamber is increased as it comes to the outer circumference of the bottom wall12c. The upper face12iof the bottom wall12cof the upper face19aof the chamber is formed into a conical inclination face which inclines upward in the axial direction (the upward and the downward direction) as it comes to the outer circumference from the central portion in the radial direction. By this upper face12i, water staying in the motor chamber11A can be positively discharged outside from the inside air communicating hole12hvia the inclined lower face19bof each chamber19and the outside ventilation hole13h.

As shown inFIG. 2, there is provided a gap t between the outer circumferential portion12dof the bottom wall12cof the pump case12and the forward end portion13bof the circumferential wall13aof the pump cover13.

Further, as shown inFIGS. 1 and 3, at the position opposed to the liquid suction port16of the circumferential wall13aof the pump cover13, the cylindrical liquid discharge port18is integrally formed being protruded. This cylindrical liquid discharge port18is communicated with each nozzle9via the liquid supply pipe8.

As shown inFIGS. 1 and 5, the filter30for filtering the washing liquid W is detachably attached in the liquid suction port16of the pump case12. This filter30is provided with a filter body31made of synthetic resin, which is attached to the liquid suction port16, for filtering the washing liquid W flowing in the liquid suction port16. As shown inFIGS. 5 to 11, the filter31is formed into a substantial cylinder having a bottom. The circumferential wall32and the bottom wall33are formed into a mesh-like filtering portion for filtering foreign objects such as dust contained in the washing liquid W. A part of the circumferential wall32is formed into a semi-cylindrical (reverse-V-shaped groove) duct portion (air passage)34extending in the longitudinal direction. As shown inFIGS. 1 and 51this duct portion34extends so that it protrudes horizontally from the opening side of the filter body31to the outside of the bottom wall33. When the filter body31is attached to the liquid suction port16of the pump case12; the cutout portion34aof the bottom face of the rear portion of the duct portion34closely comes into contact with an attachment portion16ahaving flat faces in a stepped manner in the cylindrical liquid suction port16, and the rear end portion of the duct portion34is tightly communicated with the vertical ventilation hole12fwhich is formed penetrating the bottom wall12cfor partitioning the pump chamber11B and the liquid suction port16. Due to the foregoing, as shown by the arrows inFIG. 5, air is injected into the washer tank5from the pump chamber11B flowing from the ventilation hole12fin the duct portion34so as to let out the air from the pump chamber11B.

In this connection, as shown inFIG. 12, the washing liquid pouring port5cof the washer tank5is covered with the lid5dmade of synthetic resin.

According to the washer pump10of the above embodiment, when washing liquid W is poured from the washing liquid pouring port5cinto the washer tank5, a water film is formed on the circumferential wall32and the bottom wall33which are a mesh-like filtering portion of the filter30. Due to the water film formed on the filter30, no washing liquid W enters the pump chamber11B. Therefore, the pump chamber11B is filled with air.

When an electric current generated by a predetermined electric power source is supplied from the connector15for supplying electric power via a switch not shown to the armature20of the washer pump10, the armature20is rotated. By the rotation of the armature20, in the pump chamber11B of the washer pump10, the impeller22, which is coupled to the armature shaft21in such a manner that the impeller22and the armature shaft21can not be mutually rotated with each other, is rotated. Therefore, positive air pressure is given to the outer circumferential portion of the pump chamber11B. Due to the foregoing, as shown by the arrows inFIG. 5, air is injected into the washer tank5from the pump chamber11B flowing from the ventilation hole12fof the pump case12in the duct portion34of the filter30. Due to this injection of air, the pump chamber11B is set into a state of negative pressure.

By the action of negative pressure, a water film formed on the circumferential wall32and the bottom wall33, which are a mesh-like filtering portion of the filter30, is torn away, and washing liquid W enters the pump chamber11B. Then, by the plurality of blades22bof the impeller4rotated by the armature20, washing liquid W stored in the washer tank5is sucked from the liquid suction port16into the pump chamber11B via the liquid introducing portion17and discharged from the liquid discharge port18communicating with the pump chamber11B. Washing liquid W discharged from the liquid discharge port18is sent to the nozzle9, flowing in the liquid supply pipe8and injected from the nozzle9to a washing face.

While the washing liquid w is being sucked from the liquid supply port5bof the washer tank5into the liquid suction port16of the washer pump10via the communicating member6, foreign objects such as dust can be filtered and removed by the circumferential wall32and the bottom wall33which are the mesh-like filtering portion of the filter body31engaged with the liquid suction port16. Therefore, no foreign objects are sucked into the pump chamber11B of the washer pump10. Accordingly, damage of the impeller22caused when foreign objects are mixed into the washing liquid W and blinding of the nozzle9can be positively prevented.

As described above, the filter body31of the filter30for filtering washing liquid W is engaged with the liquid suction port16of the washer pump10, and the duct portion34, which is an air passage, is integrally formed in this filter body31, and this duct portion34is communicated with the pump chamber11B via the ventilation hole12fformed on the bottom wall12cwhich partitions the pump chamber11B of the washer pump10and the liquid suction port16. Due to the foregoing, even if a water film is formed on the filter body31, when the pump chamber11B is made into a state of negative pressure by letting air out from the pump chamber11binto the washer tank5via the ventilation hole12fand the duct portion34, it is possible to tear away the water film formed on the filter body31. Due to the foregoing, washing liquid W can be positively sucked into the pump chamber11B and discharged out from the liquid discharge port18.

Between the bottom wall12c, which partitions the motor chamber11A of the washer pump10and the pump chamber11B, and the circumferential wall13aof the pump cover13, a pair of chambers19,19are formed, and the inside ventilation hole12h, which communicates with the motor chamber11A penetrating the bottom wall12con the upper face19aof each chamber19, is formed, and a plurality of outside ventilation holes13h, which communicate with the outside air, are respectively formed in the outer circumferential portion of the bottom wall13cof the pump cover13located at a lower portion in the axial direction with respect to the outer circumferential edge of the bottom wall12cof the lower face19bof each chamber19. Therefore, even when the case11of the washer pump10is covered with water in all directions, the water stays in each chamber19. Further, a labyrinth structure is formed in such a manner that each inside ventilation hole12his formed inside in the radial direction with respect to each outside ventilation hole13h. Therefore, it is possible to positively prevent the water from entering the motor chamber11A.

Concerning the bottom wall12con the upper face19aof the chamber, the upper face12iis formed into an inclined face. Even when water enters the motor chamber11A, the water is guided by the upper face12iof the bottom wall12c, which is formed on the inclined face, and moves into each inside ventilation hole12hand enters each chamber19. Therefore, even when water gets into the motor chamber11A, the water can be quickly discharged from the motor chamber11A.

The lower face19bof the chamber is formed into an inclined face in such a manner that when the lower face19bcomes close to the outer circumference of the bottom wall12c, a distance from the lower face19bto the upper face19aof the chamber is increased. Therefore, water staying in each chamber19is guided by the lower face19bof the chamber and drops downward and is positively discharged outside via each outside ventilation hole13h.

In the above embodiment, the semicylindrical duct, which is used-as an air passage, is integrally formed in the filter body of the filter, however, a cylindrical ventilation tube may be formed in the filter body so that it can be used as an air passage.

According to the washer pump described in claim1,2or3, a ventilation hole is provided on the partition wall to partition the pump chamber and the liquid suction port, a filter for filtering the washing liquid is detachably attached to the liquid suction port, an air passage is provided in the filter, and the air passage is communicated with the ventilation hole. Therefore, even if a water film is formed on the filter, when the pump chamber is made into a state of negative pressure by letting air out from the pump chamber via the ventilation hole and the air passage, it is possible to tear away the water film formed in the filter. Due to the foregoing, the washing liquid can be sucked into the pump chamber and positively discharged from the liquid discharge port.

According to the filter used for the washer pump of the invention described in claim4,5or6, a filter body for filtering the washing liquid is detachably attached to the liquid suction port, an air passage is provided in the filter body, and the air passage is communicated with a ventilation hole provided on a partition wall for partitioning the pump chamber and the liquid suction chamber. Therefore, even if a water film is formed on the filter body, when the pump chamber is made into a state of negative pressure by letting air out from the pump chamber via the ventilation hole and the air passage, it is possible to tear away the water film formed in the filter. Due to the foregoing, the washing liquid can be sucked into the pump chamber and positively discharged from the liquid discharge port.