JPH0914153A - Oil pump - Google Patents

Abstract

PURPOSE: To perform excellent discharge of oil, gathering in a gap at the periphery of a drive shaft between a rotor and an oil seal, and suppression of the increase of a pressure in the gap though an oil pump is structured in a simple and compact manner. CONSTITUTION: An oil relief groove 15 is formed in the inner circumference surface part of an inner rotor 3 coupled to the drive shaft of an oil pump and a protrusion part 18 is formed in a position on the trailing side of the oil relief groove 15 formed in the front part of the inner rotor 3. A curve or an inclination-form guide surface 19 is formed at the side end on the oil relief groove side of the protrusion part 18. Oil in the gap is fed in the oil relief groove 15 by the protrusion part 18 along with rotation of the inner rotor 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil pump used for supplying working hydraulic pressure and lubricating oil to various devices.

[0002]

2. Description of the Related Art Conventionally, various oil pumps used for supplying working oil pressure, supplying lubricating oil, etc. have been known. For example, as shown in FIGS. 8 and 9, an oil suction port 7 and an oil discharge port 8 are provided. The casing 1 has a drive shaft 2 penetrating the center of the casing 1, and an inner rotor 3 and an outer rotor 4 arranged around the drive shaft 2. The inner rotor 3 is connected to the drive shaft 2. It is generally known that oil is sucked from the suction port 7 and discharged from the discharge port 8 by rotating both the rotors 3 and 4 with the rotation of the drive shaft 2. This oil pump is attached to, for example, the end surface of the cylinder block 40 of the engine.

In this type of oil pump, the oil leaked to the inner peripheral side of the inner rotor 3 during operation is the drive shaft 2
In order to prevent the gas from flowing out through the gap 12 between the inner peripheral surface of the casing 1 and the casing 1, an oil seal 13 is provided on one end side of the gap 12 in the axial direction.

Further, if the oil seal 13 is simply provided, the oil is accumulated in the space 12 between the inner rotor 3 and the oil seal 6, and the space 12 is formed.
Since the durability and the sealing performance of the oil seal 13 may be impaired due to the increase in the pressure of the oil inside, in the conventional device shown in FIGS. 8 and 9, the oil escape hole 30 communicating with the gap 12 is provided in the casing 1. Has been formed. The oil escape hole 30 includes a vertical hole 30a that communicates with the space 12 and a horizontal hole 30b that communicates with the lower portion of the vertical hole 30a and is opened on the rear surface of the casing 1 (the surface on the side abutting the cylinder block 40). And the void 12
The oil collected in the above is discharged to the back side of the oil pump through the vertical hole 30a and the horizontal hole 30b, and is collected in an oil pan or the like (not shown).

A vertical hole 3 forming the oil escape hole 30.
0a and the horizontal hole 30b are generally formed by drilling, and a screw plug 31 is screwed to the lower end of the vertical hole 30a.

[0006]

In the conventional oil pump described above, the oil escape hole 3 is formed in the casing 1.
A space for providing 0 is required, and the axial dimension of the casing 1 is correspondingly increased, which hinders downsizing of the oil pump. Further, the oil escape hole 30
It is necessary to perform drilling of the vertical holes 30a and the horizontal holes 30b constituting the above and to mount the screw plugs 31, which increases the number of manufacturing steps and the number of parts, which causes a problem of cost increase.

In addition to the oil escape hole 30 described above,
As shown in FIGS. 8 and 9, axial grooves 15 communicating with the gap 12 are formed at appropriate positions on the inner peripheral surface of the inner rotor 3.
It is also considered that the oil in the gap 12 can be discharged to the rear side of the oil pump through the groove 15 by forming the above. However, only by forming the groove 15 on the inner peripheral surface of the inner rotor 3, it is difficult for the oil in the gap 12 to smoothly flow into the groove 15 when the inner rotor 3 is rotating at a high speed. Therefore, even if the oil escape hole 30 is omitted and the oil in the gap 12 is to be discharged only by the groove 15, the pressure increase of the oil in the gap 12 cannot be sufficiently suppressed.

In view of the above-mentioned circumstances, the present invention has a simple and compact structure and discharges the oil accumulated in the gap around the drive shaft between the rotor and the oil seal and the pressure in the gap due to the discharge. An object of the present invention is to provide an oil pump capable of achieving excellent suppression of rising.

[0009]

In order to achieve the above object, a casing having an oil suction port and an oil discharge port, a drive shaft penetrating the central portion of the casing, and a drive shaft disposed inside the casing around the drive shaft. And a rotor connected to the drive shaft, and an oil seal is provided on one axial side of a gap existing between the drive shaft and the inner peripheral surface of the casing in one axial side of the rotor. In the pump, an oil relief groove that communicates with the air gap and is continuous in the axial direction is provided on the inner peripheral surface of the rotor, and the position of the oil relief groove on the trailing side in the portion of the rotor that faces the air gap. Further, a protrusion is provided for guiding the oil in the gap to the oil escape groove as the rotor rotates.

In this oil pump, a curved or inclined guide surface that guides oil from the outer peripheral side to the inner peripheral side in the gap as the rotor rotates is provided at the side end of the protruding portion on the oil escape groove side. Is preferably formed.

Further, the oil escape groove and the protrusion are
It is preferable to dispose the rotor at a plurality of positions at predetermined intervals in the circumferential direction of the rotor.

[0012] Further, grooves communicating with the gap between the rotor and the oil seal around the drive shaft and continuous in the axial direction are provided at a plurality of positions at predetermined intervals in the circumferential direction of the rotor, It is preferable to use a part of them as a key groove and the other as an oil escape groove.

[0013]

According to the oil pump of the present invention, with the rotation of the inner rotor during the operation of the oil pump, the oil in the gap is guided to the oil escape groove by the protruding portion, and is actively discharged from the oil escape groove. Is discharged. Therefore, oil can be satisfactorily discharged from the gap without providing an oil escape hole in the casing as in the conventional case.

Particularly, when the above-mentioned curved or inclined guide surface is formed at the side end of the protruding portion on the oil escape groove side, the action of sending the oil in the gap into the oil escape groove is provided. Is increased.

By disposing the oil escape groove and the protruding portion at a plurality of positions at predetermined intervals in the circumferential direction of the rotor, the oil in the gap is sufficiently discharged by each oil escape groove.

When some of the grooves arranged at predetermined intervals in the circumferential direction of the rotor are used as key grooves and the other are used as oil relief grooves, processing for coupling the rotor and the drive shaft and discharging oil is performed. Have the same shape and are simplified.

[0017]

An embodiment of the present invention will be described with reference to the drawings.
1 to 3 show an oil pump according to an embodiment of the present invention. The oil pump of this embodiment is a trochoidal pump, and includes a casing 1, a drive shaft 2 penetrating the center of the casing 1, an inner rotor (a rotor connected to the drive shaft) 3 and an outer member arranged in the casing 1. Rotor 4
It has. When this oil pump is applied to, for example, an automobile engine, as shown in FIG. 3, the oil pump is attached to the cylinder block 40 in a state where the rear surface thereof abuts the end surface of the cylinder block.

The casing 1 is formed in a predetermined shape that is flat in the axial direction, a hollow portion 5 for inserting the drive shaft 2 is provided at the center thereof, and a space for housing the rotor is provided around the hollow portion 5 around the hollow portion 5. 6 is formed. Further, an inlet port 7 and an outlet port 8 communicating with the space 6 are formed in the casing 1 over a predetermined range in the circumferential direction, and an oil inlet hole 9 communicating with the inlet port 7, An oil discharge hole 10 communicating with the discharge side port 8 is formed.

The oil suction hole 9 is composed of a vertical hole 9a extending downward from a predetermined portion of the suction side port 7 and a horizontal hole 9b connected to the vicinity of the lower end portion thereof, and the oil discharge hole 10 is a predetermined hole of the discharge side port 8. Vertical hole 10a extending upward from the site
And a horizontal hole 10b connected to the vicinity of the upper end of the casing 1. The upstream end of the oil suction hole 9 and the downstream end of the oil discharge hole 10 reach the back surface of the casing 1. In FIG. 3, an oil passage 41 communicating with the oil suction hole 9 is provided in a cylinder block 40 to which an oil pump is attached.
An oil passage 42 communicating with the oil discharge hole 10 is formed, and the oil passage 41 is connected to an oil pan (not shown) via an oil strainer.

Space 6 for housing the rotor of the casing 1
The outer rotor 4 is rotatably fitted in the inner rotor 3 and the inner rotor 3 is arranged inwardly of the inner rotor 3. The inner peripheral boss portion 3a is connected to the drive shaft 2, and the center of rotation of the inner rotor 3 is On the other hand, the rotation center of the outer rotor 4 is eccentric by a predetermined amount. Trochoidal teeth are formed on the outer circumference of the inner rotor 3 and the inner circumference of the outer rotor 4, and mesh with each other at a predetermined position. The back side of the space 6 for housing the rotor is covered with a cover 11 attached to the casing 1 with bolts or the like.

The drive shaft 2 penetrates the casing 1 and the cover 11 and projects to the outside, and is connected to a drive means (not shown) such as an output shaft of an engine or a motor.

Between the drive shaft 2 and the peripheral wall (casing inner peripheral surface) of the hollow portion 5 of the casing 1, one side in the axial direction of the boss portion 3a of the inner rotor 3 (opposite to the rear side). The direction in which the ring-shaped void 12 exists in the direction (hereinafter, this direction is referred to as the front), and the portion on the one axial end side (the front portion)
An oil seal 13 is interposed in the.

In such an oil pump, an oil relief groove 15 is formed on the inner peripheral surface of the inner rotor 3 so as to communicate with the gap 12 and to be continuous in the axial direction. The oil escape grooves 15 are preferably provided at a plurality of positions at predetermined intervals in the circumferential direction. In the illustrated example, grooves 15 are formed at four 90 ° intervals, and one of these grooves 15 is a key groove into which a key 16 for coupling the inner rotor 3 and the drive shaft 2 is fitted. It is used and another groove serves as an oil relief.

Further, as shown in detail in FIGS. 4 to 7, the oil escape grooves 1 are formed on the front surface of the boss portion 3a of the inner rotor 3, that is, on the portion facing the gap 12.
At a position on the trailing side (rear side in the rotation direction) of 5, there is provided a protrusion 18 that guides the oil in the gap 12 to the oil escape groove 15. The protruding portion 18 protrudes from the front surface of the boss portion 3a toward the gap 12, and the front surface is close to the oil seal 13.
A guide surface 19 that guides oil from the outer peripheral side to the inner peripheral side in the gap 12 is formed at the side end on the oil escape groove side, that is, the side end on the leading side (the front side in the rotation direction).
The guide surface 19 is formed such that the radially inner portion is formed along one side of the oil escape groove 15 and the radially outer portion is curved or inclined so as to gradually move toward the leading side. Has been done.

The trailing side end 20 of the projecting portion 18 is formed in an inclined surface and is continuous with the front surface of the boss portion 3a. The arrangement of the oil escape groove 15 and the protrusion 18 and the range of formation of the protrusion 18 are set so that the next oil escape groove 15 is positioned at a constant distance from the protrusion 18 on the trailing side. .

The oil discharged through the oil escape groove 15 is collected from the back side of the oil pump to an oil storage portion such as an oil pan (not shown).

According to the oil pump of this embodiment, the inner rotor 3 is rotated as the drive shaft 2 is rotated.
Also, as the outer rotor 4 rotates, oil is sucked through the oil suction hole 9 and discharged through the oil discharge hole 10. Then, during the operation of such an oil pump, the oil leaking from the space between the rotors 3, 4 and the casing 1 to the inner peripheral side is accumulated in the gap 12, and this oil passes through the oil escape grooves 15 and It is discharged to the back side of the oil pump.

In this case, the boss portion 3 of the inner rotor 3
Since the protruding portion 18 is provided on the trailing side of the oil escape groove 15 on the front side of a, the oil in the gap 12 is guided to the oil escape groove 15 as the inner rotor 3 rotates. In particular, the protrusion 1
Since the curved or inclined guide surface 19 as described above is formed at the side end on the oil escape groove side of No. 8, the oil on the outer peripheral side in the gap 12 is scraped to the inner peripheral side and escapes. It is guided to the groove 15. Further, when the trailing side end 20 of the projecting portion 18 is formed in the shape of an inclined surface, the oil flow between the side end and the next oil escape groove 15 becomes smooth, and the oil escape groove is formed. The effect of guiding oil to 15 can be obtained even better.

In this way, as the inner rotor 3 rotates during the operation of the oil pump, the oil in the gap 12 is positively sent to the oil escape groove 15, and the gap 1
Good drainage of oil from 2. Therefore, even when the oil pump rotates at a high speed, it is possible to prevent the pressure of the oil in the space 12 from rising, and the durability and sealing performance of the oil seal are improved.

In the above embodiment, the oil escape groove 1
Although 5 is formed linearly in the axial direction of the drive shaft 2, the oil relief groove 15 is formed in a predetermined direction (the trailing side is closer to the trailing side so that the oil flowing into the oil relief groove 15 can easily flow to the rear side of the oil pump. It may be formed in a spiral shape twisted in the direction toward the side). Further, the numbers of the oil escape groove 15 and the protruding portion 18 are not limited to those in the above embodiment,
In addition to the key groove, at least one oil escape groove 15 and the corresponding protrusion 18 may be provided.

In the above embodiment, the inner rotor 3
One of the grooves 15 formed at a plurality of locations on the inner peripheral surface of the inner rotor 3 serves as a key groove, and the other portions function as oil escapes, so as to be advantageous in processing for coupling the drive shaft 2 with the drive shaft 2. However, the inner rotor 3 and the drive shaft 2 are coupled by separate means so that each groove 15
May function as a means for releasing oil.

The structure of each of the other parts may be changed without departing from the gist of the present invention.

[0033]

As described above, according to the present invention, there is a gap around the drive shaft on one side in the axial direction of the rotor connected to the drive shaft, and the oil seal is provided on one end side in the axial direction. In the oil pump, an oil relief groove communicating with the gap is provided on the inner peripheral surface of the rotor,
A protrusion is provided at the position on the trailing side, and this protrusion causes oil in the gap existing around the drive shaft in front of the rotor to be guided to the oil escape groove as the rotor rotates. The oil in the gap can be positively discharged from the oil escape groove during operation of the pump. Therefore, even when the oil pump rotates at a high speed, it is possible to prevent the pressure of the oil in the gap from rising and to maintain the durability and sealability of the oil seal provided in the front portion of the gap well. As described above, it is not necessary to form the oil escape hole in the casing, and the oil pump can be downsized and the cost can be reduced.

In the present invention, a curved or inclined guide surface for guiding the oil from the outer peripheral side to the inner peripheral side in the gap as the rotor rotates is provided especially at the side end of the protruding portion on the oil escape groove side. By forming the above, it is possible to sufficiently enhance the action of sending the oil in the gap into the oil escape groove during the operation of the oil pump.

[0035]

[Brief description of the drawings]

FIG. 1 is a rear view of an oil pump according to an exemplary embodiment of the present invention, taken along line I-I of FIG.

FIG. 2 is a sectional view taken along the line II-II of FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG. 1;

FIG. 4 is a front view of an inner rotor of the oil pump.

FIG. 5 is a sectional view of the inner rotor.

FIG. 6 is an enlarged front view of a part of the inner rotor.

FIG. 7 is an enlarged view of a part of the inner rotor seen from below.

FIG. 8 is a rear view of a conventional oil pump.

9 is a sectional view taken along the line IX-IX in FIG.

[Explanation of symbols]

 1 Casing 2 Drive Shaft 3 Inner Rotor 4 Outer Rotor 7 Suction Port 8 Discharge Port 12 Gap 13 Oil Seal 15 Oil Relief Groove 18 Projection 19 Guide Surface

Claims (4)

[Claims] 1. A casing having an oil intake port and an oil discharge port, a drive shaft penetrating a central portion of the casing, and a rotor arranged around the drive shaft in the casing and connected to the drive shaft. In addition, in an oil pump provided with an oil seal on one axial side of a gap existing between the drive shaft and the casing inner peripheral surface on one side in the axial direction of the rotor, the inner peripheral surface portion of the rotor is provided with An oil relief groove communicating with the air gap and continuous in the axial direction is provided, and at the position of the trailing side of the oil relief groove in the portion of the rotor facing the air gap, the oil in the air gap is moved as the rotor rotates. An oil pump provided with a protrusion that guides to the oil relief groove. 2. A curved or inclined guide surface for guiding the oil from the outer peripheral side to the inner peripheral side in the gap as the rotor rotates is formed at a side end of the protruding portion on the oil escape groove side. The oil pump according to claim 1, wherein: 3. The oil pump according to claim 1 or 2, wherein the oil relief groove and the protrusion are arranged at a plurality of positions at predetermined intervals in the circumferential direction of the rotor. 4. Grooves communicating with the space between the rotor and the oil seal around the drive shaft and continuous in the axial direction are provided at a plurality of positions at predetermined intervals in the circumferential direction of the rotor, The oil pump according to any one of claims 1 to 3, wherein a part of them is a key groove and the other is an oil escape groove.