JPH09317423A - Oil pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably prevent the abrasion and seizure of sliding points in an oil pump at its restarting by providing a recess at a position of a rotor housing approaching its center from the bottom face of teeth of an outer rotor and supplying residual working fluid in the recess to sliding points between an inner rotor and the outer rotor. SOLUTION: When a drive shaft 22 is rotated to cause the relative rotation of an inner rotor and an outer rotor 26, working fluid OL led by a lubricating oil circulation passage 16a is sucked through an inlet passage 52 and an inlet port 42 into confined parts in an oil pump and is fed therefrom through a discharge port 40 and a discharge passage 54 into a lubricating oil circulation passage 16b. When such an oil pump is stopped during a longer period of time, part of the working fluid OL which have flowed out of the sliding parts into the discharge port 40 is prevented from flowing into the discharge passage 54 by a projection 58 to thereby reside in the recess 56 and in tooth space 26a of the outer rotor 26. Upon the restarting of the oil pump the working fluid in the recess 56 and the like are led into the sliding parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relatively rotates an inner rotor having a tooth portion formed along the circumferential direction and an outer rotor having a tooth groove meshing with the tooth portion along the circumferential direction. Accordingly, the present invention relates to an oil pump that performs an operation of discharging the hydraulic oil after the hydraulic oil is sucked by the closing portion formed by the tooth portion and the tooth groove.

[0002]

2. Description of the Related Art As an oil pump, an internal gear pump is known, and the internal gear pump is installed in a crankshaft of an engine body as disclosed in, for example, Japanese Utility Model Laid-Open No. 1-58788. An inner rotor having a plurality of teeth connected to a drive shaft that rotates in an interlocking manner, an outer rotor having an outer peripheral portion of the inner rotor having tooth grooves meshing with the teeth of the inner rotor, and a rotor accommodating portion accommodating the inner rotor and the outer rotor. And a pump housing part having the same.

In the pump housing portion, there is a suction passage portion having a suction port for supplying working oil to a closing portion formed by the tooth portion of the inner rotor and the tooth groove of the outer rotor, and the operation sucked by the closing portion. A discharge passage portion having a discharge port for discharging oil is provided.

When the oil pump is stopped for a relatively long period of time, the hydraulic oil in the oil pump is returned to the oil pan. Therefore, when restarting, between the tooth groove of the outer rotor and the tooth portion of the inner rotor. The oil film is not sufficiently formed on the sliding contact portion and the sliding portion between the inner surface portion of the rotor housing portion and the outer peripheral surface of the outer rotor, which may cause abrasion or seizure.

In order to avoid such a situation, the suction port portion of the pump housing portion is provided with, for example, an actual opening 2-3.
As also disclosed in Japanese Patent No. 7208, when the oil pump is stopped, a protruding wall that suppresses the return of the hydraulic oil to the suction passage portion in order to leave a part of the hydraulic oil in the suction port portion. It is proposed to have a section.

[0006]

However, when the wall portion is provided in the suction port portion as described above, when the inner rotor is rotated in a relatively high rotation range, the hydraulic oil introduced into the suction port portion is Cavitation phenomenon may occur due to being squeezed by the wall, and as a result, the wall may adversely affect the ejection performance.

In view of the above problems, according to the present invention, an inner rotor having tooth portions formed along the circumferential direction and an outer rotor having tooth grooves meshing with the tooth portions along the circumferential direction are relatively arranged. An oil pump that is operated to discharge hydraulic oil after being sucked by a closing portion formed by a tooth portion and a tooth groove by rotating the blade in relation to the inner rotor and the outer rotor. It is an object of the present invention to provide an oil pump that can surely avoid wear and seizure in the moving part and that does not adversely affect the discharge performance.

[0008]

In order to achieve the above object, an oil pump according to the present invention has an outer rotor having a tooth groove and a tooth portion forming a closed portion by meshing with the tooth groove of the outer rotor. A pump housing having an inner rotor, a rotor accommodating portion that rotatably accommodates the outer rotor and the inner rotor, an intake port portion that sends operating oil to the closing portion, and a discharge port portion that discharges the operating oil sent by the closing portion. And a recess in which the hydraulic oil remains is provided in the vicinity of the discharge port of the pump housing and at a position closer to the center of the rotor housing than the tooth bottom surface of the outer rotor, facing the rotor housing. is there.

In the second aspect of the invention, the recess may be provided in the vicinity of the discharge port portion on the side toward the direction in which the volume of the closing portion decreases.

According to the third aspect of the present invention, the peripheral portion of the concave portion may be provided with a projection portion for damming the hydraulic oil at a position closer to the center of the rotor accommodating portion than the tooth bottom surface of the outer rotor.

[0011]

2 and 4 show an example of an oil pump according to the present invention together with a part of an engine body provided with the oil pump.

2 and 4, an inclined surface portion 10a to which a pump housing portion 14 of an oil pump 12 described later is fixed is formed on a wall portion of the cylinder block of the engine body 10. The slope 10a is shown in FIG.
In the direction indicated by the arrow V, that is, the engine body 1
It is formed with a predetermined gradient in the vertical direction of 0. Further, the slanted surface portion 10a is open at the respective end portions of the lubricating oil circulation passages 16a and 16b provided inside the cylinder block.

The oil pump 12 is, for example, an internal gear pump, and has a drive shaft 22 to which the timing belt pulley 20 is fixed at one end and a plurality of tooth portions 24a connected to the other end of the drive shaft 22. The inner rotor 24 has and a plurality of tooth grooves 26a that mesh with the tooth portions 24a of the inner rotor 24.
An outer rotor 26 having a rotor housing 26, a pump housing portion 14 having a rotor housing portion 28 for housing the inner rotor 24 and the outer rotor 26 at one end, and a pump housing portion 14 disposed between the timing belt pulley 20 and the pump housing portion 14. And a pump cover member 30 that covers one end face of the.

A timing belt 18 wound around a timing belt pulley provided on a crank shaft (not shown) is wound around a timing belt pulley 20 having a hub fixed to one end of a drive shaft 22. There is. As a result, when the engine body 10 is operated, the crankshaft is rotated and the drive shaft 22 is rotated in the direction indicated by the arrow F in FIG.

As shown in FIG. 4, the pump cover member 30 has a through hole 30 through which the drive shaft 22 penetrates in a substantially central portion thereof.
a. One end of the pump cover member 30 projects into a concave portion inside the timing belt pulley 20 and is close to the inner peripheral portion of the timing belt pulley 20.
Further, a concave portion 30b is provided on the peripheral portion of the through hole 30a at one end thereof. A seal member 32 is arranged in the recess 30b. The seal member 32 prevents the hydraulic oil from leaking out through the gap between the inner peripheral surface of the through hole 30a and the outer peripheral surface of the drive shaft 22.

The other end surface of the pump cover member 30 is in contact with one end surface of the pump housing portion 14,
A circular groove 30c in which the O-ring 34 is arranged is provided. At a plurality of positions on the periphery of the pump cover member 30,
A through hole 30d through which the plurality of bolts Ba are respectively inserted is provided, and the pump cover member 30 serves as the pump housing portion 1.
4 is fixed to one end face of the bolt 4 by a bolt Ba.
As a result, the rotor housing portion 28 of the pump housing portion is sealed. Further, the pump cover member 30
A lubricating oil supply passage 30e is formed in the inside of the recess 30b so that the recess 30b communicates with the other end surface of the pump cover member 30.

The inner rotor 24 has a through hole 24b in which the other end of the drive shaft 22 is fixed on the common axis line, and a plurality of, for example, six tooth portions 24a are circumferentially provided on the outer peripheral portion thereof. They are arranged in equal divisions along the direction. The tooth profile of the tooth portion 24a is, for example, a trochoidal tooth profile.

The outer rotor 26 is rotatably arranged in a rotor accommodating portion 28 of the pump housing portion with a predetermined eccentric amount in a direction indicated by an arrow V shown in FIG. 2 outwardly with respect to a central axis of the inner rotor 24. There is. Outer rotor 26
The outer circumferential surface of the rotor housing 28
It is regulated by being slidably fitted to the inner peripheral surface of
Further, the axial position of the outer rotor 26 is regulated by the both end surfaces being in sliding contact with the bottom surface portion of the rotor housing portion 28 and the other end surface of the pump cover member 30. Accordingly, between the inner peripheral surface and the bottom surface portion of the rotor housing portion 28 and the outer peripheral surface and the end surface of the outer rotor 26, the rotor housing portion 2
A sliding surface portion is formed between the bottom surface portion 8 and the end surface of the inner rotor 24.

On the inner peripheral portion of the outer rotor 26, a plurality of, for example, six tooth grooves 26a with which the tooth portions 24a of the inner rotor 24 mesh are arranged in the circumferential direction in equal divisions.

When the inner rotor 24 is rotated in the direction indicated by arrow F in FIG. 2, the outer rotor 26 is rotated in the rotor accommodating portion 28 in the same direction as the inner rotor 24.

A closed portion 36 is formed by a space surrounded by the tooth groove 26a of the outer rotor 26 and the adjacent tooth portion 24a of the inner rotor 24. The volume of the closing portion 36 changes due to the rotation of the inner rotor 24, and when the inner rotor 24 is rotated in the direction indicated by the arrow F in FIG.
It is assumed that it increases in the direction indicated by the arrow V in FIG. 2 and decreases in the direction opposite to the direction indicated by the arrow V. Therefore, the pressure in the closing portion 36 rises as the inner rotor 24 is rotated in the direction indicated by the arrow V in FIG. 2 toward the top dead center, and heads toward the bottom dead center in the direction opposite to the direction indicated by the arrow V. As it goes down.

The pump housing portion 14 has a slope 10a.
Female screw portion 10c provided to face each other at a predetermined interval
Through holes 14c and 14b through which the bolts Bc and Bb pass, respectively, at positions corresponding to the positions of and 10b.
Are provided substantially parallel to each other.

On the end surface of the pump housing portion 14 with which the pump cover member 30 abuts, female screw portions 14s into which the bolts Ba are fitted are provided at positions corresponding to the through holes 30d of the pump cover member 30, respectively. There is.

In the rotor accommodating portion 28, as shown in FIGS.
As shown in, a support hole 38 that rotatably supports the other end of the drive shaft 22 is provided. A suction port portion 42 and a discharge port portion 40 are provided around the support hole 38 so as to face each other. A communication passage 44 that guides the hydraulic oil from the discharge port portion 40 to the inner peripheral portion of the support hole 38 is provided between the discharge port portion 40 and the support hole 38.

At one end of the suction port portion 42, the connecting passage portion 4 for communicating the suction port portion 42 with the relief passage portion 46 is provided.
2a is provided. The other end of the connection passage portion 42a is connected to an intermediate portion of the relief passage portion 46 via a communication passage 50 provided along the axis of the drive shaft 22.

A connecting passage portion 40a is provided at one end of the discharge port portion 40 to connect the discharge port portion 40 to the starting end portion of the relief passage portion 46.

The relief passage portion 46 extends in a direction intersecting the axial direction of the drive shaft 22 and substantially in parallel with the inclined surface portion 10a at a predetermined interval. On the other hand, the end portion of the relief passage portion 46 is sealed by the plug 48. When the pressure at the terminal end of the relief passage portion 46, that is, the pressure at the discharge port portion 40 becomes equal to or higher than a predetermined value, the connection passage portion 40a and the connection passage portion 42a are automatically brought into communication, and the discharge port A relief mechanism is provided that automatically disconnects the connecting passage portion 40a and the connecting passage portion 42a when the pressure of the portion 40 falls below a predetermined value.

As shown in FIG. 1, the other end of the intake port portion 42 is connected to an open end of an intake passage 52 communicating with the lubricating oil circulation passage 16a of the engine body 10.

On the other hand, the other end of the discharge port portion 40 is, as shown in FIG. 1, a lubricating oil circulation passage 1 of the engine body 10.
6b is connected to the open end of the discharge passage 54 communicating with 6b. Further, in the vicinity of the opening end of the discharge passage 54 at the other end of the discharge port portion 40, as shown in FIGS. 1 and 4, a concave portion 56 in which hydraulic oil remains is formed on the wall portion forming the discharge port portion 40. It is set up in a row. A protrusion 58 is formed on the peripheral edge of the recess 56 on the opening end side of the discharge passage 54 to restrict a part of the residual hydraulic oil from flowing into the opening end of the discharge passage 54. Also, the protrusion 5
8 and the position of the bottom of the recess 56 in the direction indicated by the arrow V is higher than the position of the bottom surface of the tooth groove 26a of the outer rotor 26 closer to the center C side of the rotor accommodating portion 28, that is, higher than the slope portion 10a. The position is.

With such a structure, when the drive shaft 22 is rotated and the inner rotor 24 and the outer rotor 26 are relatively rotated, the working oil from the lubricating oil circulation passage 16a moves through the suction passage 52 and the suction port portion 42. The hydraulic oil that is sucked into each of the closing portions 36 through and is pressurized and held in each of the closing portions 36 is conveyed to the discharge port portion 40, and is transferred to the lubricating oil circulation passage 16 a through the discharge passage 54. Will be supplied.

After the oil pump 12 has been operated in this way, when the oil pump 12 is stopped for a relatively long period of time, the hydraulic oil OL that has flowed out of each of the closing portions 36 to the discharge port portion 40. As shown in FIGS. 1 and 4, the protrusion 58 restricts a part of the gas from flowing out into the discharge passage 54, and the recess 56 and the tooth groove 2 of the outer rotor 26 are prevented.
A predetermined amount remains in 6a. As a result, when the oil pump 12 is restarted under the condition that the oil surface is formed along the direction of the arrow H indicating the horizontal direction orthogonal to the arrow V shown in FIG. The hydraulic oil remaining in 56 and the hydraulic oil in the tooth groove 26a of the outer rotor 26 are slid between the tooth groove 26a of the outer rotor 26 and the outer rotor 26 and the rotor accommodating portion 28 by the rotation of the inner rotor 24 and the outer rotor 26. Will be introduced to the department.

At this time, since the bottom of the recess 56 and the projection 58 are set higher than the bottom surface of the tooth groove 26a of the outer rotor 26 along the direction indicated by the arrow V with respect to the slope 10a, the recess 56 is formed. The hydraulic oil inside is easily introduced into the tooth groove 26a of the outer rotor 26 and the sliding portion between the outer rotor 26 and the rotor accommodating portion 28.
Further, since the position where the concave portion 56 is provided corresponds to the position where the volume of the closing portion 36 is relatively small, it is possible to avoid adversely affecting the ejection performance.

Therefore, when the oil pump 12 is restarted from the stopped state for a relatively long period of time, the tooth groove 26a of the outer rotor 26 and the hydraulic oil in the recess 56 cause the tooth groove 26a of the outer rotor 26 and the outer rotor 26 and the rotor. An oil film is easily and reliably formed on the sliding portion between the housing portion 28 and the housing portion 28. As a result, it is possible to surely avoid abrasion and seizure in the sliding portions related to the inner rotor and the outer rotor at the time of restart, and to prevent the discharge performance from being adversely affected.

[0034]

As is apparent from the above description, according to the oil pump of the present invention, the rotor housing is located in the vicinity of the discharge port of the pump housing and faces the rotor housing rather than the tooth bottom surface of the outer rotor. Since the hydraulic oil remaining in the concave portion is provided to the sliding portion related to the inner rotor and the outer rotor because the concave portion is provided at the position on the center side of the portion, the oil pump is related to the inner rotor and the outer rotor when restarting. It is possible to reliably avoid wear and seizure on the sliding portion.

Further, since the concave portion is provided in the discharge port portion on the side toward the direction in which the volume of the closed portion decreases, it is possible to surely avoid abrasion and seizure in the sliding portion without adversely affecting the discharge performance. it can.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of an example of an oil pump according to the present invention together with a part of an engine body provided with the same.

FIG. 2 is a cross-sectional view showing a main part of an example of an oil pump according to the present invention together with a part of an engine body provided with the same.

FIG. 3 is a cross-sectional view showing a main part of an example of an oil pump according to the present invention together with a part of an engine body provided with the same.

FIG. 4 is a sectional view taken along line IV-IV in the example shown in FIG.

[Explanation of symbols]

 12 oil pump 14 pump housing part 24 inner rotor 24a tooth part 26 outer rotor 26a tooth groove 28 rotor accommodating part 36 closing part 40 discharge port part 42 suction port part 56 concave part 58 protrusion part OL hydraulic oil

Claims (3)

[Claims] 1. An outer rotor having a tooth groove, an inner rotor having a tooth portion that forms a closed portion by meshing with the tooth groove of the outer rotor, and a rotor accommodating portion that rotatably accommodates the outer rotor and the inner rotor.
A suction port portion for sending hydraulic oil to the closing portion, and
A pump housing part having a discharge port part for discharging the hydraulic oil sent by the closing part, wherein the recess where the hydraulic oil remains is near the discharge port part in the pump housing part, and the teeth of the outer rotor are provided. An oil pump, which is provided at a position closer to the center of the rotor housing than the bottom surface and faces the rotor housing. 2. The oil pump according to claim 1, wherein the recessed portion is provided in the vicinity of the discharge port portion on the side toward the direction in which the volume of the closing portion decreases. 3. The peripheral portion of the recess is formed with a protrusion for stopping the hydraulic oil at a position closer to the center of the rotor accommodating portion than the tooth bottom surface of the outer rotor. The oil pump according to claim 2.