JP2003172270A - Oil pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of cavitation erosion on an inner surface of a housing in an oil pump in which a large number of operation chambers are provided on an outer periphery of a rotor. <P>SOLUTION: Along an outer periphery of the rotor 30 of which both side surfaces slide in a gear chamber formed on a casing H, a large number of operation chambers of which a volume is increased/decreased while moved with a rotation of the rotor are formed. An operation oil suctioned from a suction passage 21 is delivered from a delivery passage 26. A reinforcement member 18 is buried and fixed into an inner side surface of the gear chamber with which the rotor slides. With the rotor as a drive gear, a driven gear 31 of which both side surfaces slide in the gear chamber is engaged with the drive gear. Thereby, the operation chambers may be formed between the teeth of both gears. The reinforcement member comprises a material having high resistance against the cavitation erosion and may be provided at a part of the inner side surface of the gear chamber where the cavitation is generated. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil pump for supplying hydraulic oil to an automatic transmission of an automobile.

[0002]

2. Description of the Related Art In this type of oil pump, as shown in FIGS. 6 and 7, a drive gear 30 and a driven gear 31 having internal teeth meshing with the drive gear 30 are formed in a circular housing recess 2 formed in a pump body 1. It is housed and covered with the pump cover 3 in a liquid-tight manner, and the volume of the working chamber R formed between the teeth of both gears 30 and 31 meshing with each other on the inner surfaces of the pump body 1 and the pump cover 3 gradually increases. Pair of suction side concave grooves 4a, 4 facing each other at a position corresponding to the suction region
There is also one in which a pair of discharge side concave grooves 6a and 6b facing each other are opened at a position corresponding to the discharge region where the volume of the working chamber R gradually decreases.

In the illustrated example, the suction-side concave grooves 4a and 4b are suction ports 4a and 4b which communicate with the suction passage 5.
The discharge side concave groove 6a on the pump body 1 side is a discharge port 6a communicating with the discharge passage 7, and the discharge side concave groove 6b on the pump cover 3 side is a concave groove not communicating with the discharge passage 7. The drive gear 30 is supported on the tip of the input shaft 8 supported in the center hole of the pump body 1 via the bearing bush 9, and a pair of keys 30 a protruding from the inner surface of the drive gear 30 is attached to the tip of the input shaft 8. The key groove 8a formed in the above is engaged to rotate and drive.

If the drive gear 30 is rotated in the clockwise direction as shown by the two-dot chain line arrow in FIG.
1 is also rotated in the same direction, the working oil passes through the suction passage 5 and is sucked from the suction ports 4a and 4b on both sides into the suction region between the gears 30 and 31, and is discharged from the discharge region into the discharge port 6a. It is supplied to the supply destination through the discharge passage 7.

[0005]

As shown in FIG. 7, rotation of the drive gear 30 causes both gears 3 in the suction region.
The hydraulic oil sucked into each working chamber R between the teeth of 0 and 31 is
Between the rear ends of the suction-side concave grooves 4a and 4b and the front ends of the discharge-side concave grooves 6a and 6b, the gears are confined between the teeth of the pump body 1 and the pump cover 3 and the gears 30 and 31, and thus the gears 3 and 3.
It is moved clockwise with the rotation of 0, 31. The hydraulic oil thus confined is communicated with the discharge side concave grooves 6a, 6b at the moment when the tip of the working chamber R communicates with the front ends of the discharge side concave grooves 6a, 6b, and the pressure sharply rises. Erosion due to cavitation (hereinafter simply referred to as cavitation erosion) is generated and eroded on the inner surfaces of the pump body 1 and the pump cover 3 immediately in front of the front ends of the discharge side concave grooves 6a and 6b, and the internal leakage of the oil pump increases and oil is increased. This causes a problem that the discharge performance of the pump deteriorates.

The deterioration of the discharge performance due to such internal leakage becomes a problem especially when the pump body 1 and the pump cover 3 are made of a light alloy (for example, aluminum) die-cast product for weight reduction. As a means for solving such a problem, for example, as disclosed in Japanese Utility Model Laid-Open No. 5-6167, a liner for covering the axial one end surface and the outer peripheral surface of the drive gear and the driven gear is provided inside the accommodation recess, and the liner is provided. Is considered to be a material such as duralumin, which has high resistance to cavitation erosion. However, such a method requires a large-sized liner, which causes a problem of increasing manufacturing cost.

It is an object of the present invention to prevent cavitation erosion in such an oil pump, prevent deterioration of the discharge performance of the oil pump due to an increase in internal leakage, and suppress an increase in manufacturing cost required therefor. .

[0008]

To this end, an oil pump according to the present invention comprises a housing in which an intake passage, a gear chamber and a discharge passage are formed, and a gear chamber of the housing having both inner side surfaces of the gear chamber. A rotor that is rotatably arranged so that its surface slides, and a large number of partitions that are formed between the housing and the rotor along the outer circumference of the rotor and whose volume increases and decreases while moving as the rotor rotates. In an oil pump that has a chamber and sucks working oil from the suction passage by the rotation of the rotor and discharges this working oil from the discharge passage, a reinforcing member is embedded and fixed in a part of the inner surface of the gear chamber in which the rotor slides. It is characterized by that.

In the oil pump according to the present invention, the rotor is the drive gear, and the driven gear is rotatably supported in the housing so that both sides and the outer periphery slide with the inner surface of the gear chamber and meshes with the drive gear. It is preferable that the working chamber is formed between the teeth of the both gears that mesh with each other.

The reinforcing member of the oil pump according to the present invention comprises:
It is preferable to embed and fix the inner surface of the gear chamber at least in a portion where cavitation erosion occurs.

The reinforcing member of the oil pump according to the present invention comprises:
It is preferable that the reinforcing member is made of a material harder than the material forming the member to be embedded and fixed. Further, it is particularly preferable that the reinforcing member is made of a material having higher resistance to cavitation erosion than the material forming the member in which the reinforcing member is embedded and fixed.

It is preferable that the casing of the oil pump according to the present invention comprises a pump body and a pump cover coupled and fixed to the pump body.

Further, in the oil pump according to the present invention, the rotor is a drive gear having external teeth, and a driven gear having internal teeth, which is rotatably supported on both sides and the outer periphery of the inner surface of the gear chamber and meshes with the drive gear, is provided in the housing. A working chamber is formed between the teeth of both levers that mesh with each other, and the reinforcing member is located on the inner surface of the housing through which both sides of the working chamber open on both sides of both gears are located slightly in front of the discharge side concave groove. It is preferable to provide.

The reinforcing member of the oil pump according to the present invention is preferably press-fitted and fixed in a round bottomed mounting hole formed on the inner surface of the housing.

Further, it is preferable that the housing of the oil pump according to the present invention is provided with a vent hole for communicating the space between the bottom surface of the mounting hole and the reinforcing member press-fitted into the mounting hole to the outside.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first embodiment shown in FIGS. 1 to 3 will be described. The oil pump according to the first embodiment supplies operating oil to an automatic transmission of an automobile, and mainly comprises a drive gear (rotor) 30, a driven gear 31 having internal teeth meshing with the drive gear (rotor) 30, both gears 30, Three
A housing H that rotatably accommodates 1
The housing H is formed by a pump body 10 and a pump cover 15 which are joined to each other.

As shown mainly in FIG. 1, both gears 30, 3 are provided on one flat side surface of the pump body 10 made of cast iron.
A circular, shallow accommodation recess 11 having a constant depth is formed to rotatably accommodate 1 and the inner bottom surface of the accommodation recess 11 has the same eccentricity between the gears 30 and 31 with respect to the center of the accommodation recess 11. A central hole 12 is formed so as to be eccentric by the amount and penetrate the pump body 10. The pump cover 15 made of aluminum has a flat side surface so as to liquid-tightly cover the housing recess 11 in which both gears 30 and 31 are housed.
It is bolted to 0, and the housing recess 11 of the pump body 10
And the pump cover 15 covering the both gears 30,
A gear chamber for housing 31 is formed. A tubular stator shaft 17 press-fitted and fixed in a central hole 16 formed in a pump cover 15 coaxially with the central hole 12 of the pump body 10.
Passes through the inside of the pump body 10 with a gap between it and the center hole 12, and the tubular input shaft 35 inserted between the stator shaft 17 and the center hole 12 is a bearing fixed to the inner surface of the center hole 12. The bush 13 is rotatably supported, and an oil seal 36 seals between the input shaft 35 and the pump body 10.

The drive gear 30 having external teeth and the driven gear 31 having internal teeth having one tooth larger than the drive gear 30 have the same thickness.
It has trochoidal teeth that mesh with each other, their sides and pump body 10 and pump cover 15
Both inner side surfaces of the gear chamber formed by are relatively slidably rotatable with a small clearance such that the hydraulic oil does not substantially leak. The drive gear 30 has an input shaft 35 on its inner peripheral surface.
The pair of keys 30a, which are supported by being fitted to the outer peripheral surface of the distal end portion and project from the inner peripheral surface, are engaged with the key grooves 35a formed at the distal end of the input shaft 35 and are rotationally driven. There is. The outer peripheral surface of the driven gear 31 is the accommodation recess 1
It is rotatably fitted and supported on the inner peripheral surface of the roller 1.

As shown mainly in FIG. 2, both gears 30,
The space between 31 and the inner surface of the housing H is partitioned into a large number of working chambers R along the outer periphery of the drive gear 30 by the teeth meshing with each other, and each working chamber R moves as the gears 30, 31 rotate. However, the volume increases and decreases. Then, from the contact position of the pitch lines of both gears 30, 31 to both gears 30, 3
A suction region in which the volume of the working chamber R gradually increases with rotation is formed in a range of 180 degrees in the rotation direction of 1, and rotation is made in a range of 180 degrees in the direction opposite to the rotation direction from the contact position of the pitch line. Accordingly, a discharge region in which the volume of the working chamber R gradually decreases is formed.

As shown in FIGS. 1 and 2, the inner bottom surface of the accommodating recess 11 of the pump body 10 and the inner surface of the pump cover 15 corresponding thereto have an opening along the corresponding portion corresponding to the suction area, as shown in FIGS. A pair of suction ports (suction side concave grooves) 20a, 20b having the same shape and area are formed so as to face each other, and the inner edge and the outer edge of each suction port 20a, 20b are of the gears 30, 31 respectively. It matches the root circle. A suction passage 21 that is formed in the pump body 10 and the pump cover 15 and introduces hydraulic oil from a reservoir (not shown) is connected to the suction ports 20a and 20b.

As shown in FIGS. 2 and 3, the inner bottom surface of the accommodating recess 11 of the pump body 10 and the inner surface of the pump cover 15 corresponding thereto are opened along a corresponding portion corresponding to the discharge area, as shown in FIGS. Discharge port (discharge side concave groove) 25a and discharge side concave groove 25b having the same shape and area
Are formed to face each other. The inner edge and the outer edge of the discharge port 25a and the discharge-side concave groove 25b are respectively attached to the respective gears 3
It matches the root circle of 0,31. The discharge port 25a communicates with a discharge passage 26 formed in the pump body 10 and the pump cover 15 for supplying hydraulic oil to a supply destination. However, the discharge side concave groove 25b is shallower than the discharge port 25a in order to avoid a fluid passage (not shown) formed in the pump cover 15, and is not communicated with the discharge passage 26.

As shown in FIGS. 2 and 3, on the inner surface of the pump cover 15, a round bottomed bottom is formed by machining at a position where the side surface of the working chamber R passes slightly forward of the front end of the discharge side concave groove 25b. The mounting hole 18a of
A short columnar reinforcing pin (reinforcing member) 18 made of a material (for example, duralumin, high silicon (high silicon aluminum alloy), iron, etc.) having higher resistance to cavitation erosion than the pump cover 15 is press-fitted and fixed to a. The tip thereof comes into contact with the peripheral portion of the bottom surface of the mounting hole 18a and is stopped. Further, a mounting hole 19a similar to the mounting hole 18a is formed on the inner surface of the pump cover 15 between the rear end of the discharge side groove 25b and the suction port 20b, and the reinforcing pin 19 similar to the reinforcing pin 18 is press-fitted. It is fixed. After press-fitting and fixing the both reinforcing pins 18 and 19, the inner surface of the pump cover 15 and the both reinforcing pins 18 and 1 are fixed.
9 is processed so that the surfaces of the reinforcing pins 18 and 19 become a part of the inner surface of the pump cover 15. Further, the pump cover 15 is formed with ventilation holes 18b and 19b for communicating the space between the bottom surfaces of the mounting holes 18a and 19a and the reinforcing pins 18 and 19 press-fitted into the ventilation holes 18b and 19b. The increase in air pressure between the bottom surfaces of the mounting holes 18a and 19a and the reinforcing pins 18 and 19 due to is prevented to prevent the reinforcing members 18 and 19 from coming out.

During operation of the oil pump, the drive gear 30 supported by the tip of the input shaft 35 is rotated in the clockwise direction as indicated by the two-dot chain line arrow in FIG. 2, and the driven gear 31 is also rotated in the same direction. The working chamber R is also moved in the same direction. As a result, the working oil in the reservoir passes through the suction passage 21 and is sucked into the working chamber R in the suction region from the suction ports 20a and 20b on both sides, and is discharged from the working chamber R in the discharge region into the discharge port 25a. It is supplied to the supply destination through the passage 26. At this time, the working oil sucked into the working chamber R is pump body 10, pump cover 15, both gears 30 between the rear end of the suction side concave grooves 20a, 20b and the front ends of the discharge port 25a and the discharge side concave groove 25b. , 31 are trapped between the teeth of the gears 31 and 31 and are moved in the clockwise direction as the gears 30 and 31 rotate. The confined hydraulic oil is discharged from the discharge port 2 at the moment when the tip of the working chamber R communicates with the front ends of the discharge port 25a and the discharge-side concave groove 25b.
5a and the discharge side concave groove 25b are communicated with each other, and the pressure sharply rises, so that cavitation erosion tends to occur on the inner surface of the pump cover 15 which is in contact with this.

However, on the inner surface of the pump cover 15 made of aluminum, the cavitation erosion resistance is set at a position where the side surface of the working chamber R passes a little forward of the front end of the discharge side concave groove 25b, that is, a position where this cavitation erosion occurs. Since the reinforcing pin 18 made of a large material is press-fitted and fixed so that its surface becomes a part of the inner surface of the pump cover 15, the reinforcing pin 18 prevents cavitation erosion that occurs on the inner surface of the pump cover 15. Therefore, the problem that the inner surface of the pump cover 15 is eroded by the cavitation erosion, the internal leakage of the oil pump increases, and the discharge performance of the oil pump deteriorates is avoided. Moreover, since the reinforcing pin 18 is provided on the inner surface of the portion where cavitation erosion is most likely to occur, and a small area is sufficient, an increase in manufacturing cost is suppressed.

The discharge passage 26 on the pump body 10 side is also provided.
In the discharge side concave groove 25b in which the hydraulic fluid in the discharge port 25a communicating with each other has a large flow and the relative speed with each gear 30, 31 is small, while the discharge passage 26 on the pump cover 15 side is not communicated. The hydraulic oil of the
The pressure of the hydraulic oil in the discharge side concave groove 25b becomes smaller than the pressure of the hydraulic oil in the discharge port 25a due to the reason that the relative speed with respect to 31 becomes large. As a result, both gears 30,
31 is pressed against the pump cover 15 side, and its side surface is brought into contact with the inner surface of the pump cover 15. However, the two reinforcing members 18 and 19 made of a material having a high resistance to erosion, which is press-fitted and fixed between the suction port 20b and the front and rear ends of the discharge side groove 25b, are harder than the material of the pump cover 15 and are also wear resistant. Since it is normally rich, abrasion of the inner surface of the pump cover 15 due to contact with the gears 30 and 31 is prevented. The stagnation of the hydraulic oil in the discharge side groove 25b is large at the rear part of the rotation direction of both gears 30 and 31, and therefore the pressure in the discharge side groove 25b is particularly reduced at this rear part, so that both gears at this rear part. 30 and 31 are particularly strongly contacted with the inner surface of the pump cover 15. However, since this is mainly received by the reinforcing pin 19,
Local wear on this part is also prevented.

In the first embodiment, a round mounting hole 18a is formed in the inner surface of the pump cover 15 by machining, and the reinforcing pin 18 is press-fitted and fixed. By doing so, the reinforcing pin 18 is embedded and fixed. Since it can be performed extremely easily, it is possible to suppress an increase in manufacturing cost on the processed surface. However, the present invention is not limited to this, and the pump cover 15 may be formed by processing the material of the pump cover 15 in which the reinforcing member 18 made of a material having high resistance to the cavitation erosion described above is cast in advance. In this way, the shape of the reinforcing member 18 can be freely adjusted according to the range where cavitation erosion occurs.

When the pump body 10 made of cast iron and the pump cover 15 made of aluminum are used as in this embodiment, it is usually sufficient to provide the reinforcing pin 18 only on the inner surface of the pump cover 15. When the pump body 10 is made of aluminum, a reinforcing member similar to the reinforcing member 18 provided on the pump cover 15 may be provided on the inner bottom surface of the housing recess 11 of the pump body 10. Also in the case of the cast iron pump body 10, cavitation erosion may occur at a position where the side surface of the working chamber R passes slightly forward of the front end of the discharge port 25a on the inner bottom surface of the housing recess 11. In such a case, At that position, a reinforcing member 18 made of a material having higher resistance to cavitation erosion than cast iron may be provided.

Next, a second embodiment shown in FIGS. 4 and 5 will be described. Also in the second embodiment, as in the first embodiment, mainly the drive gear 30, the driven gear 31 having internal teeth meshing with the drive gear 30, and the both gears 30, 3 are provided.
Housing H that forms a gear chamber that rotatably accommodates 1
The housing H is formed by the pump body 10 and the pump cover 15.
The structure of 0, driven gear 31, and the portion directly related to this is different from that of the first embodiment.

Mainly as shown in FIG. 4, the accommodating recess 11 for accommodating both gears 30 and 31 formed on one flat side surface of the pump body 10 is the same as that of the first embodiment, and is eccentric to the center hole. 12 is formed, but is different in that a crescent-shaped partition 14 described below is formed so as to project from the inner bottom surface of the accommodation recess 11. The pump cover 15 that covers the pump cover 15 in a liquid-tight manner has an inner surface abutting on the top surface of the partition 14, and a central hole 16 is formed coaxially with the central hole 12.

The drive gear 30 and the driven gear 31 have involute tooth-shaped teeth that mesh with each other, and the number of teeth of the driven gear 31 is 2 more than the number of teeth of the drive gear 30.
It is larger than one. The drive gear 30 is rotatably supported by the center holes 12 and 16 of the pump body 10 and the pump cover 15 via an integrally formed input shaft 35. As shown in FIG. 5, the addendums of the gears 30 and 31 are slidable with a slight gap between the inner peripheral surface and the outer peripheral surface of the crescent-shaped partition 14.

As shown in FIG. 5, between the gears 30 and 31 and the inner surface of the housing H, a large number of working chambers R formed along the outer periphery of the driven gear 31 are formed.
A suction region in which the volume of the working chamber R gradually increases with rotation is formed between the pitch line contact position of 0, 31 and one end of the partition 14, and the other of the partition 14 is formed from the pitch line contact position. A discharge region in which the volume of the working chamber R gradually decreases with rotation is formed between the tips.

As with the first embodiment, the pump body 1
Suction ports 20a and 20b having the same opening shape and area are formed on the inner bottom surface of the housing recess 11 of 0 and the inner surface of the pump cover 15 so as to face each other along a corresponding portion corresponding to the suction region. A suction passage 21 communicates with each of the suction ports 20a and 20b. Also pump body 1
As shown in FIGS. 4 and 5, the inner bottom surface of the accommodating recess 11 of 0 and the inner surface of the pump cover 15 have substantially the same shape and area of the opening along a considerable portion corresponding to the discharge area. The ejection port 25a and the ejection-side concave groove 25b are formed to face each other. The discharge port 25a is connected to a discharge passage 26 that is formed in the pump body 10 and the pump cover 15 and supplies hydraulic oil to the supply destination. The discharge-side concave groove 25b is the same as that of the first embodiment. , Is shallower than the discharge port 25a and is not communicated with the discharge passage 26.

As shown in FIG. 5, the inner surface of the pump cover 15 is rounded at a position where the side surface of the working chamber R passes slightly forward of the front end of the discharge side groove 25b, as in the first embodiment. A bottomed mounting hole 18a is formed, and this mounting hole 18a
A short columnar reinforcing pin 18 made of a material having high resistance to cavitation erosion is press-fitted and fixed in the. Further, a mounting hole 19a is also formed on the inner surface of the pump cover 15 between the rear end of the discharge side groove 25b and the suction port 20b, and the reinforcing pin 1 similar to the reinforcing pin 18 is formed.
9 is press-fitted and fixed. Both the reinforcing pins 18 and 19 are machined at the same time as the inner surface of the pump cover 15 after being press-fitted and fixed, and the pump cover 15 is provided with a space for communicating the space between the bottom surfaces of the mounting holes 18a and 19a and the reinforcing pins 18 and 19 to the outside. Pores 18b and 19b are formed. The configuration of the second embodiment other than the above is the same as that of the first embodiment.

When the drive gear 30 supported at the tip of the input shaft 35 is rotated clockwise as indicated by the double-dashed line arrow in FIG. 5, the driven gear 31 is also rotated in the same direction and the working oil is sucked. Intake ports 20 on both sides through passage 21
a, 20b is sucked into the working chamber R in the suction region,
It is discharged from the working chamber R in the discharge region into the discharge port 25a and is supplied to the supply destination through the discharge passage 26. At this time, for the same reason as described in the first embodiment,
Pump body 10, pump cover 15 and both gears 3
The hydraulic oil trapped between the teeth of 0 and 31 is
At the moment when the tip end of the pump communicates with the tip of the discharge port 25a and the discharge side concave groove 25b, the pressure is rapidly increased by being communicated with the discharge port 25a and the discharge side concave groove 25b. Try to cause cavitation erosion.

However, on the inner surface of the pump cover 15 made of aluminum, at the position where the cavitation erosion occurs, the reinforcing pin 18 made of a material having a large resistance to the cavitation erosion is press-fitted and fixed, so that the cavitation that occurs on the inner surface of the pump cover 15 is formed. Erosion is prevented by the reinforcing pin 18. Therefore, the pump cover 15
The problem that the internal leak of the oil pump increases and the discharge performance of the oil pump is deteriorated due to the erosion of the inner surface of the oil pump is avoided, and since the reinforcing pin 18 requires only a small area, the increase of the manufacturing cost is suppressed.

For the same reason as described in the first embodiment, the pressure of the hydraulic oil in the rear portion of the discharge side groove 25b becomes smaller than the pressure of the hydraulic oil in the discharge port 25a.
The driven gear 31 is pressed against the pump cover 15 side in the vicinity of the rear portion of the discharge port 25a, and its side surface is brought into contact with the inner surface of the pump cover 15. However, the reinforcing pins 18 and 1 that are press-fitted and fixed to the inner surface of the pump cover 15
Since No. 9 also has high wear resistance, the inner surface of the pump cover 15 will not be worn by the contact with the gear 31. The drive gear 30 of the second embodiment
Since the integrally provided input shaft 35 is supported by the pump body 10 and the center holes 12 and 16 of the pump cover 15, there is no risk of tilting like the driven gear 31, and movement in the axial direction is also possible. Since it is restrained by 35, it does not come into contact with the inner surface of the pump cover 15. Since the description of the other operational effects and the modified examples is the same as that of the first embodiment, detailed description is omitted.

In the above-described two embodiments, the case of the gear pump including the drive gear 30 having external teeth and the driven gear 31 having internal teeth has been described, but the present invention is directed to the inner peripheral surface of the gear chamber of the housing and the inner peripheral surface of the gear chamber. The space between the eccentrically rotated rotors is partitioned by a large number of vanes slidably provided in the radial direction with respect to the rotor, and the tip of which is slidably abutted against the inner peripheral surface of the gear chamber. A large number of working chambers whose volume increases and decreases while moving with the rotation of the gear chamber are formed.The inner surface of the gear chamber has a suction port at a position corresponding to the suction region where the volume of the working chamber increases, and the volume of the working chamber decreases. It can also be applied to a vane pump having a discharge port opened at a position corresponding to the discharge region. Even with such a vane pump, the pressure of the hydraulic oil trapped in the working chamber rises abruptly at the moment when the tip of the working chamber communicates with the discharge port. There is a problem that cavitation erosion occurs on the inner surface of the housing, which causes corrosion. However, as in the above-described embodiments, a reinforcing member made of a material having high resistance to cavitation erosion is embedded and fixed on the inner surface of the housing, which is slightly forward of the front end of the discharge-side concave groove through which the respective working chambers communicate with each other first. By doing
The problem of such erosion is solved and the increase in manufacturing cost is suppressed.

[0038]

As described above, according to the present invention, since the reinforcing member is embedded and fixed to a part of the inner side surface of the gear chamber in which the rotor slides, the portion where the reinforcing member is embedded and fixed is eroded and worn. There is no possibility that the internal leakage of the oil pump will increase due to such erosion or wear and the discharge performance of the oil pump will deteriorate. Further, since the reinforcing member may be formed in a concentrated manner on a portion of the inner surface of the gear chamber where erosion and wear are likely to occur, it is possible to suppress an increase in manufacturing cost.

The rotor is a drive gear, and a driven gear, which is rotatably supported so that both sides and the outer circumference slide on the inner surface of the gear chamber, and which meshes with the drive gear, is provided in the housing. By forming the working chamber between the parts, each effect described above can be obtained in the gear pump.

If the reinforcing member is embedded and fixed in at least a portion of the inner surface of the gear chamber where cavitation erosion occurs, erosion of the inner surface of the gear chamber due to cavitation can be prevented.

The reinforcing member is made of a material that is harder than the material that forms the member in which the reinforcing member is embedded and fixed, or that is more resistant to cavitation erosion than the material that forms the member in which the reinforcing member is embedded and fixed. According to the present invention, it is possible to more effectively prevent abrasion of the inner surface of the gear chamber or erosion due to cavitation erosion.

If the casing of the oil pump is made up of the pump body and the pump cover connected and fixed to the pump body, the productivity of the oil pump is improved.

The rotor is used as an external tooth drive gear, and a driven gear having internal teeth is provided in the housing, both sides and outer periphery of which are rotatably supported by the inner surface of the gear chamber and meshes with the drive gear, and both gears mesh with each other. A working chamber whose volume increases and decreases is formed between the teeth, and the reinforcing member is provided on the inner surface of the housing through which both sides of the working chamber pass, which is open to both sides of both gears, slightly to the front of the discharge side concave groove. According to the above, cavitation erosion occurs on the inner surface of the housing mainly in the range where both sides of the working chamber opened to both sides of both gears pass slightly forward of the front end portion of the discharge side concave groove, so that erosion prevention is prevented. A very small reinforcing member is sufficient. Therefore, an increase in manufacturing cost for preventing erosion can be further suppressed.

When the reinforcing member is press-fitted and fixed in the round bottomed mounting hole formed on the inner surface of the housing, the reinforcing member can be embedded and fixed very easily, so that the manufacturing cost for preventing erosion is increased. The increase can be further suppressed.

According to the housing having the ventilation hole for communicating the space between the bottom surface of the mounting hole and the reinforcing member press-fitted into the housing, the reinforcing member may not come off due to the temperature rise accompanying the operation of the oil pump. Disappear.

[Brief description of drawings]

FIG. 1 is a sectional view of a central portion of a first embodiment of an oil pump according to the present invention.

2 is a front view of the pump cover taken along line 2-2 of FIG. 1. FIG.

3 is a sectional view taken along line 3-3 of FIG.

FIG. 4 is a sectional view of a central portion of a second embodiment of the oil pump according to the present invention.

5 is a front view of the central portion of the pump cover taken along line 5-5 of FIG.

FIG. 6 is a sectional view of a central portion of an example of an oil pump according to the related art.

7 is a front view of the central portion of the pump cover taken along line 7-7 of FIG.

[Explanation of symbols]

18, 19 ... Reinforcing member (reinforcing pin), 18a ... Mounting hole,
18b ... Vent hole, 20a, 20b ... Suction side concave groove (suction port), 25a ... Discharge side concave groove (discharge port), 25b ...
Discharge side concave groove, 30 ... Rotor (drive gear), 31 ... Driven gear, H ... Housing, R ... Working chamber.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Osamu Takeuchi             10 Akane, Takane, Fujii-cho, Anjo City, Aichi Prefecture             N AW Co., Ltd. F-term (reference) 3H041 AA02 BB03 CC03 CC13 CC15                       DD04 DD33                 3H044 AA02 BB03 CC03 CC12 CC14                       DD04 DD23

Claims (9)

[Claims] 1. A housing in which an intake passage, a gear chamber and a discharge passage are formed, and a rotor rotatably disposed in the gear chamber of the housing so that both side surfaces slide on both inner side surfaces of the gear chamber. And a plurality of operating chambers formed between the housing and the rotor along the outer circumference of the rotor, the operating chamber being partitioned into a large number of volumes whose volume increases and decreases while moving with the rotation of the rotor. An oil pump that sucks hydraulic oil and discharges the hydraulic oil from the discharge passage, wherein a reinforcing member is embedded and fixed to a part of an inner side surface of the gear chamber in which the rotor slides. 2. The oil pump according to claim 1, wherein the rotor is a drive gear, and both sides and an outer periphery are rotatably supported in the housing so as to slide on an inner surface of the gear chamber. An oil pump characterized in that a driven gear that meshes with a gear is provided, and the working chamber is formed between tooth portions of the both gears that mesh with each other. 3. The oil pump according to claim 1 or 2, wherein the reinforcing member is embedded and fixed in at least a portion of the inner surface of the gear chamber where cavitation erosion occurs. 4. The oil pump according to any one of claims 1 to 3, wherein the reinforcing member is made of a material that is harder than a material forming a member in which the reinforcing member is embedded and fixed. Characteristic oil pump. 5. The oil pump according to claim 4, wherein the reinforcing member is made of a material having higher resistance to cavitation erosion than a material forming a member in which the reinforcing member is embedded and fixed. . 6. The oil pump according to claim 1, wherein the casing comprises a pump body and a pump cover fixedly coupled to the pump body. . 7. The oil pump according to any one of claims 1 to 6, wherein the rotor is a drive gear having external teeth, and both sides and an outer periphery of the rotor rotate on an inner surface of the gear chamber. A driven gear having internal teeth that is freely supported and meshes with the drive gear is provided to form the working chamber between the meshing tooth portions of both gears, and the reinforcing member is provided slightly ahead of the discharge-side concave groove. An oil pump provided on an inner surface of the housing through which both sides of the working chamber opened to both sides of the both gears pass. 8. The oil pump according to any one of claims 1 to 7, wherein the reinforcing member is press-fitted and fixed in a round bottomed mounting hole formed on the inner surface of the housing. Oil pump to do. 9. The oil pump according to claim 8, wherein a ventilation hole is formed in the housing for communicating the space between the bottom surface of the mounting hole and the reinforcing member press-fitted into the mounting hole to the outside. Oil pump.