JPH09166094A - Oil pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce internal leakage of operating oil to a clearance and a noise accompanied by cavitation, by arranging between a driving shaft and a bearing metal, a lubricating spiral groove which is inclined so as to introduce operating oil to a rotor side so that it is extended from the rotor side end of the bearing metal to an anti-rotor side. SOLUTION: Lubricating spiral grooves 61, 62 which are inclined so as to introduce operating oil to a rotor side, are arranged among a driving shaft and bearing metals 18, 19. These spiral grooves 61, 62 are extendedly arranged from the rotor side ends of the bearing metals 18, 19 to the end of an anti-rotor side, and also arranged on the inner circumferential surfaces of the bearing metals 18, 19. When the driving shaft is rotatively driven in an L direction, the inclining directions of the spiral grooves 61, 62 are reversed to the conventional directions. Hereby, leakage oil can be suppressed as much as possible from being released from the spiral grooves 61, 62 by thread effect developed by opposing the inclining directions of the spiral grooves 61, 62 and the rotational direction of the driving shaft.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil pump such as a vane type used as a hydraulic pressure source in a power steering device for reducing a steering wheel operating force of an automobile.

[0002]

2. Description of the Related Art An oil pump of this kind is used as a hydraulic power source in a power steering device, for example, and various structures such as a vane type displacement type and a variable displacement type have been proposed. There is.

As an example thereof, the outline of a vane type variable displacement oil pump will be described with reference to FIGS. 5 and 6, and a vane type oil pump generally designated by reference numeral 10 is a front body constituting a pump body. 11 and a rear body 12. As shown in FIG. 5, the entire front body 11 has a substantially cup shape, and a pump component 1 as a pump cartridge is provided inside the front body 11.
A storage space 14 for storing and arranging 3 is formed, and the rear body 12 is combined and integrated so as to close the open end of the storage space 14.

A ball bearing 17 as a bearing and both sides of the rotor 15 are provided in the front body 11 in a state where a drive shaft 16 for rotationally driving the rotor 15 as a rotor of the pump component 13 from the outside penetrates the front body 11. It is rotatably supported by a pair of bearing metals 18 and 19 located. The ball bearing 17 is provided at an outer end portion of the shaft hole in a portion projecting outward of the front body 11, and an oil seal 17a is provided inside thereof. The bearing metal 18 is arranged at the inner end of the shaft hole of the front body 11, and the bearing metal 19 is arranged at the shaft hole of the front body 12 to support the drive shaft 16.

Reference numeral 20 denotes a cam ring having an inner cam surface 20a fitted and arranged on the outer peripheral portion of the rotor 15 having a vane 15a and forming a pump chamber 21 between the inner cam surface 20a and the rotor 15. , This cam ring 20
It is arranged so as to be movable and displaceable in an adapter ring 22 fitted into an inner wall portion of the storage space 14 so as to change the volume of the pump chamber 21. 23 is the rotor 15 described above,
A pressure plate is arranged in pressure contact with the front body 11 side of a pump cartridge (pump component 13) constituted by a cam ring 20 and an adapter ring 22, and the end face of the rear body 12 is a side surface on the opposite side of the pump cartridge. The plates are pressed against each other, and the front body 11 and the rear body 12 are integrally assembled into a desired assembled state.

Here, the pressure plate 23 and the rear body 12 laminated on the pressure plate 23 via the cam ring 20.
Means that the cam ring 20 is integrally assembled and fixed in a state of being positioned in the rotational direction by a shaft support portion for swinging displacement of the cam ring 20, a seal pin 25 functioning as a positioning pin, and an appropriate detent means (not shown). There is. Reference numeral 26 denotes a pump discharge side pressure chamber formed on the bottom side in the storage space 14 of the front body 11, and the pump discharge side pressure acts on the pressure plate 20 by the pressure chamber 26. 2
Reference numeral 7 denotes a pump discharge side opening formed in the pressure plate 23 so as to guide the pressure oil from the pump chamber 21 to the pump discharge side pressure chamber 23.

28 is a front body 1 as shown in FIG.
It is a pump suction port provided in a part of 1.
The suction side fluid flowing in from the pump suction side passage 28a formed in the front body 11 through the valve hole 30a of the control valve 30 described later, and continuously formed in the front body 11 and the rear body 12. Passage 2
It is supplied into the pump chamber 21 through the pump suction side opening 29 that opens through the end surface of the rear body 12 through 8 b and 28 c. Here, in this example, in order to guide the suction side fluid from the suction port 28 to the pump chamber 21, the suction side passages 28a and 28b that straddle the control valve 30, that is, penetrate the valve hole 30a are used.

Reference numeral 32 in FIG. 6 is a discharge port for feeding the fluid pressure on the pump discharge side to a hydraulic device such as a power steering device (PS in the figure) which is not shown. It is an opening from the pump chamber 21 to the pump discharge side opening. 27, a pump discharge side pressure chamber 26, a fluid passage hole 33 formed in a different position of the pressure plate 23, a second fluid pressure chamber 37 described later,
A plug 4 that houses a spring 41 that biases the cam ring 20.
The fluid pressure on the pump discharge side is fed through the spring chamber 42a formed by 2 and the notch groove 43 formed in the front body 11 and the passage hole 44 formed in the body 11.

Here, the above-mentioned pump discharge side passage (2
7, 26, 33, 42a, 43, 44, 32), a variable metering orifice 40 for increasing or decreasing the opening area is formed by the fluid passage hole 33 opening to the second fluid pressure chamber 37 and the side wall portion of the cam ring 20. Has been done. That is, the variable metering orifice 40 is configured by opening and closing the passage hole 33 in the side wall portion in accordance with the displacement of the cam ring 20.

Reference numeral 30 is a control valve disposed substantially orthogonally above the storage space 14 in the front body 11, and a variable metering orifice for fluid pressure control for moving and displacing the cam ring 20 with respect to the rotor 15 in the adapter ring 22. 40. This control valve 30
Is the pump discharge side passage (27, 26, 33, 42a, 43, 44, 3 in the valve hole 30a formed in the body 11).
2) A spool 30b that slides on the downstream side of the variable metering orifice 40 provided by the pressure difference on the downstream side and the urging force of the spring 41 is provided. In this control valve 30, one chamber (the left chamber in FIG. 6) of the spool 30b is
A fluid passage 26a extending from the pump discharge side pressure chamber 26,
The fluid pressure on the upstream side of the variable metering orifice 40 is introduced via 26b.

A spring 30c is arranged in the other chamber (right chamber in FIG. 6) of the spool 30b, and a fluid pressure downstream of the variable metering orifice 40 described above reaches the discharge port 32 midway. That is, it is guided from the second fluid pressure chamber 37 through the fluid passage 22a formed between the body 11 and the adapter ring 22 and the fluid passage 30d formed in the body 11.

As described above, the pump suction side passage 28a continuous with the suction port 28 is formed through substantially the center of the valve hole 30a, and the suction is performed through the annular space defined by the annular groove of the spool 30b. Side fluid is delivered.
A first fluid pressure chamber 36, which will be described later, formed between the adapter ring 22 and the cam ring 20 is connected between the opening of the suction side passage 28a and the opening of the discharge side fluid passage 26b. Passage 2 of adapter ring 22
2b and the fluid passage 30e bored in the body 11 are opened, and as shown in FIG. 6, the land is communicated with the pump suction side passage 28a at all times so that the suction side fluid pressure is transferred to the first fluid pressure chamber 36. Introduce.

Reference numerals 36 and 37 denote the outer peripheral portion of the cam ring 20 and the seal pin 2 between the outer peripheral portion and the inner periphery of the adapter ring 22.
5 and the first and second fluid pressure chambers divided into the left and the right by the seal member 38 provided at the substantially axisymmetric position thereof, and the first fluid pressure chamber is generated in accordance with the operation of the control valve 30 described above. A pump discharge side fluid pressure on the pump suction side or the variable metering orifice 40 upstream side is introduced into 36, and a pump discharge side fluid pressure on the variable metering orifice 40 downstream side is introduced into the second fluid pressure chamber 37.

The variable metering orifice 40
Due to the opening area that varies between the fluid passage hole 33 and the side wall of the cam ring 20, the flow rate is raised to a predetermined flow rate when the rotational speed is low, and the flow rate is decreased when the rotational speed becomes higher than a certain value. It is controlled so that a flow rate of about half the initial flow rate can be obtained at a rotational speed or higher. In addition,
In the vane type variable displacement pump 10 as described above, configurations other than those described above are widely known in the related art, and a detailed description thereof will be omitted.

[0015]

In the oil pump 10 having the conventional structure as described above, both ends of the rotor 15 axially supported on the drive shaft 16 in the axial direction are the bearing metal 1.
A front body 11 and a rear body 12 are rotatably supported by 8 and 19. A slit of the rotor 15 (indicated by reference numeral 47 in FIGS. 5 and 6) at the time of pump operation in the space sandwiched between the bearing metals 18 and 19 in the rotor shaft support portion of the drive shaft 16 as described above. The pressure oil on the pump discharge side, which is introduced into the base end of the vane 15a that can be freely moved in and out, leaks. That is, in the rotor 15, the base end portion 47a of the slit 47 for the vane 15a and the pressure plate 2 facing the base end portion.
Although not shown in the drawings, arcuate groove portions 48 and 49 formed on the end surface of the rear body 3 and the end surface of the rear body 12 guide pressure oil on the pump discharge side from the pump discharge side pressure chamber 26, and the hydraulic pressure thereof causes slits in the rotor 15 It is configured to urge the vane 15a from 47 in the radial direction.

Therefore, in such a pump structure,
The high pressure oil in the above-mentioned slit base end portion 47a and the arcuate groove portions 48, 49 on both sides thereof passes through the gap due to the side clearance between the pressure plate 23 and the end surface of the rear body 12 on both surface sides of the rotor 15. , A void portion 50 formed in the shaft support portion of the rotor 15 in the drive shaft 16.
It is inevitable to accumulate in. The gap between the rotor 15 and the members on both sides of the rotor 15 is necessary to facilitate the rotational movement of the rotor 15. However, if the leaked oil accumulates in the rotor shaft supporting portion more than necessary, it causes a problem when the drive shaft 16 and the rotor 15 are rotationally driven. This is not only a load when the drive shaft 16 and the rotor 15 are rotationally driven when leaked oil accumulates in the gap of the rotor shaft supporting portion and becomes high pressure, but also the bearing metal 1
Since the pump suction pressure is applied to the outer end sides of the bearing metal 18, particularly the outer end sides of the bearing metal 18, the pressure difference causes a force to push the bearing metal 18 to the left in FIG.
There may be a problem in rotating the.

For this reason, conventionally, a pair of bearings for rotatably supporting the drive shaft 16 by being interposed between the bodies 11 and 12 and the drive shaft 16 at both ends of the rotor 15 in the axial direction. 7 (a), on the inner peripheral surface of the metal 18, 19.
As shown in FIG. 8B or FIGS. 8A and 8B, the spiral groove 5
1, 52 are formed, and these spiral grooves 51, 52 positively allow the leaked oil to escape to the end side of the bearing metals 18, 19 on the side opposite to the rotor 15 side, so that the rotor shaft support portion has a high pressure. It was preventing. In addition, such bearing metal 1
The spiral grooves 51 and 52 on the inner peripheral surfaces of 8 and 19 have a function as a groove for lubricating the space between the bearing metals 18 and 19 and the drive shaft 16 by the leaked oil. Particularly, in the conventional pump structure, the space on the outer end side of the bearing metal 19 on the inner end side of the drive shaft 16 is a dead end, and even if the working oil is released to the outside by the above-mentioned spiral groove 52, the working oil is discharged. However, it is effective in distributing the working oil to the bearing metal 19 to obtain the function as the lubricating oil. Further, if it reaches this portion, the hydraulic oil will escape from the spiral groove 51 of the bearing metal 18 on the opposite side to the pump suction side.

For example, FIGS. 7A and 7B show the drive shaft 16
Bearing metal 18, 1 when rotating in the direction of arrow L in the figure
9 shows a state in which the spiral grooves 51 and 52 are formed in the groove 9. In the figure, 18a and 19a are bearing metals 18 and 1, respectively.
In FIG. 9, the end portion on the rotor 15 side and 18b and 19b indicate the end portions on the side opposite to the rotor. Then, in these drawings, the operating oil flowing into the spiral grooves 51, 52 is rotated between the rotation direction of the drive shaft 16 and the inclination direction of the bearing metals 18, 19 of the spiral grooves 51, 52. Depending on the relationship
As shown by the imaginary line in the figure, it flows to the side opposite to the rotor. In contrast to FIG. 7 described above, FIGS. 8A and 8B show the case where the drive shaft 16 is rotating in the direction of arrow R in the drawing. In this case, the spiral grooves 51 and 52 are The inclination direction is opposite to that of the above-described FIG. 7, whereby the rotation of the drive shaft 16 causes the hydraulic oil to flow to the side opposite to the rotor.

Then, as described above, the conventional drive shaft 16
In the shaft support structure of FIG. 7, the inclination direction of the spiral grooves 51, 52 formed on the inner peripheral surfaces of the bearing metals 18, 19 by the spiral is as shown in FIG.
As shown in (a), (b) or FIGS. 8 (a), (b), in relation to the rotation direction of the drive shaft 16, the rotor 1
The leaked oil is discharged from the side 5 to the side opposite to the rotor 15 and, as a result, the gap portion 5 formed in the shaft supporting portion of the rotor 15
The pressure of 0 becomes low pressure. However, at such a low pressure, the working oil is more likely to leak from the pump chamber 21 through the gap between the pressure plate 23 and the end surface of the rear body 12 on both sides of the rotor 15 in the gap portion 50. , The amount of hydraulic oil leaking from the pump chamber 21 increases,
This has been a problem in improving the desired pump efficiency in this type of pump. In particular, in this type of pump, it is desired to maximize the discharge amount from the pump chamber to improve the efficiency of the entire pump, and it is necessary to minimize the leakage inside the pump.

The oil thus leaked contains air bubbles, and when the air bubbles leak into the air gap 50 of the rotor shaft supporting portion, which has a low pressure as described above, the high pressure causes a low pressure. The transition to the state causes expansion, and so-called cavitation occurs. When such leaked oil is returned to the suction side of the pump, the leaked oil is sucked into the pump chamber 21 again, which causes a problem of noise due to the cavitation.

The present invention has been made in view of the above circumstances, and reduces the internal leakage amount of the hydraulic oil from the pump chamber to the void portion in the rotor shaft support portion of the drive shaft, and further, in this void portion. The purpose of the present invention is to obtain an oil pump which has a simple structure and is inexpensive in view of the problem of noise caused by the occurrence of cavitation.

[0022]

In order to meet such demands, an oil pump according to the present invention is provided with a drive shaft penetratingly arranged in a pump body, and a rotary shaft provided on the drive shaft and rotated in the pump body. A driving rotor and a pair of bearing metals that rotatably support both ends of the drive shaft in the axial direction of the rotor with respect to the pump body are provided, and hydraulic oil is directed to the rotor side between the driving shaft and the bearing metal. A lubricating spiral groove inclined so as to lead is provided from the end of the bearing metal on the rotor side to the end on the opposite side of the rotor. Here, the above-mentioned lubricating spiral groove is provided on the inner peripheral surface of the bearing metal or on the outer peripheral surface of the drive shaft that is in sliding contact with the inner peripheral surface of the bearing metal. Further, the pump body is provided with an escape passage for connecting a gap on the end side of the bearing metal on the side opposite to the rotor of the pump body to the suction side in the pump.

According to the present invention, leakage of oil due to high-pressure hydraulic oil from the pump chamber formed by the rotor escapes from the spiral groove formed in the bearing metal via the rotor shaft support of the drive shaft. Suppressed as much as possible by the screw effect by matching the inclination direction of the groove and the rotation direction of the drive shaft,
This keeps the pressure at the rotor shaft support at a predetermined level,
The amount of oil leaking from the pump chamber inside the pump body can be reduced as much as possible.

Further, according to the present invention, leaked oil leaks from the pump chamber through the gap between the rotor and the pressure plates on both sides thereof, and the rear body serving as the side plate, and collects in the gap of the rotor shaft support portion of the drive shaft. Excessive amount of oil is returned to the pump suction side from the spiral grooves of each bearing metal provided at both ends in the axial direction of the rotor, the voids on the metal outer end side, and the respective escape passages.

The oil pump refers to, for example, a vane type variable displacement pump, but also includes a vane type displacement pump, and further includes a gear pump and a screw pump. In short, any pump may be used as long as both ends of the drive shaft in the axial direction of the drive shaft, which has a rotor for sucking and discharging hydraulic oil as a pump, are rotatably supported on the pump body by bearing metal. Further, the spiral groove provided on the inner circumference of the bearing metal includes one or a plurality of spiral grooves in the circumferential direction. Such a spiral groove may be formed on either the inner peripheral surface of the bearing metal or the outer peripheral surface of the drive shaft with which the sliding contact is made.

[0026]

1 to 6 show one embodiment of an oil pump according to the present invention. In these drawings, an oil pump generally designated by the numeral 10 is schematically shown in FIG.
As described above with reference to FIG. 6 and FIG. Here, in FIG. 5, reference numerals 55 and 56 are bearing metals 18 and 19 in the pump bodies 11 and 12.
Is an escape passage formed in the front body 11 and the rear body 12, which are pump bodies, so as to connect the gaps 57 and 58 on the side opposite to the rotor 15 to the suction side in the pump.

According to the present invention, in the oil pump 10 having the above-mentioned structure, the pump body 11, 12 having the rotor 15 having the function of sucking and discharging the working oil is provided.
The drive shaft 16 which is disposed so as to penetrate therethrough, and the drive shaft 16
The two axial end portions of the rotor 15 of the pump body 11, 1
A pair of bearing metals 18 and 1 rotatably supported with respect to 2
9 are provided between the drive shaft 16 and the bearing metals 18 and 19 and lubricating spiral grooves 61 and 62 inclined so as to guide the working oil to the rotor 15 side are provided on the rotor side of the bearing metals 18 and 19. It is provided from the end portion to the end portion on the side opposite to the rotor. Here, the above-mentioned lubricating spiral grooves 61 and 62 are provided on the inner peripheral surfaces of the bearing metals 18 and 19, as shown in FIG. 1 or 2.

1 (a) and 1 (b), the spiral groove 6 when the drive shaft 16 is rotationally driven in the L direction in the figure.
1 and 62 show the inclination directions, and FIGS. 1 (a) and 1 (b) are opposite to the above-mentioned conventional examples shown in FIGS. 7 (a) and 7 (b).

The effect of the relationship between the inclination direction of the spiral grooves 61 and 62 and the rotation direction of the drive shaft 16 is shown in FIG.
The details are described below with reference to FIG. Here, the bearing metal 18 side shown in FIG. 1A will be described from the description. That is, in the bearing metal 18, when the drive shaft 16 rotates in the direction indicated by L, a flow equivalent to a uniform laminar flow in a narrow gap between parallel flat plates, which is a so-called Quette flow, occurs in the spiral groove 61. As shown in FIG. 3, the hydraulic oil causes a flow in the spiral groove 61 with a peripheral velocity component of u. On the other hand, bearing metal 18
The flow of the hydraulic oil due to the pressure gradient at both end portions occurs in the direction indicated by arrow H in the figure.

The flow of hydraulic oil in such a state will be described with reference to FIG. 4. When the state at the point X in FIG. 4A is analyzed, the pressure gradient as shown in FIG. Is generated toward the outer end of the bearing metal 18,
The peripheral velocity component u associated with the rotation direction of the drive shaft 16 is as shown in FIG. 7D, and when these are combined, as shown by the broken line in FIG. Thus, a resistance force acts to push the hydraulic oil back to the rotor 15 side or to prevent the hydraulic oil from escaping from the rotor 15 side to the outside. Then, due to the screw effect of the spiral groove 61, the working oil is accumulated in the void portion 50 on the rotor 15 side or the rotor 1
It will be pushed back to the 5 side.

Therefore, in such a structure, the leakage oil due to the high-pressure hydraulic oil from the pump chamber 21 formed by the rotor 15 passes through the rotor shaft support portion (gap portion 50) of the drive shaft 16 and the bearing metal 18, The escape from the spiral grooves 61 and 62 provided in 19 can be suppressed as much as possible by the screw effect by making the inclination directions of the spiral grooves 61 and 62 correspond to the rotation direction of the drive shaft 16. And
As a result, the pressure in the void portion 50 can be maintained at a required pressure, so that the amount of oil leaking from the pump chamber 21 inside the pump bodies 11, 12 can be reduced.

Further, in such a structure, since the amount of leaked oil can be reduced, it is possible to suppress the expansion of bubbles in the leaked oil, thereby preventing the occurrence of cavitation and suppressing the occurrence of noise problems. Of course, excess leakage oil flows through the spiral grooves 61 and 62 of the bearing metals 18 and 19.
The lubricity of the drive shaft 16 can be ensured. Further, in the above-described configuration, since the pump suction side and the outer end sides of the bearing metals 18, 19 are connected by the escape grooves 55, 56, these escape grooves 55, 56 are formed when the vehicle runs at a low speed.
From 56, the hydraulic oil on the pump suction side is transferred to each bearing metal 18,
It flows through the spiral grooves 61 and 62 of 19 into the space 50 of the rotor shaft support. As a result, the operating oil is guided as lubricating oil to the shaft-supporting portions of the drive shafts 16 of the bearing metals 18 and 19, so that it is possible to ensure lubricity when the vehicle runs at low speed. Further, since the pump suction side and the outer end sides of the bearing metals 18 and 19 are connected by the relief grooves 55 and 56 described above, the pressures acting from both end sides of the rotor 15 in the axial direction are balanced. There are also advantages.

Needless to say, leakage oil leaks from the pump chamber 21 through the gap between the rotor 15 and the pressure plates 23 on both sides of the rotor 15 and the rear body 12 and accumulates in the gap 50 of the rotor shaft support portion of the drive shaft 16 in excess of the necessary amount. Is returned to the pump suction side (passages 28a, 28c) from the spiral grooves 61, 62 of the bearing metals 18, 19 through the voids 57, 58 on the metal outer end side and the escape passages 55, 56.

Here, the inclination direction of the above-mentioned spiral grooves 61, 62 is determined by the relationship with the rotation direction of the drive shaft 16, and is shown in FIGS. 1 (a), 1 (b) or 2 (a),
It may be configured as shown in (b). These drawings have a configuration opposite to that of the conventional case shown in FIGS. 7 and 8. Further, such groove widths and inclination angles of the spiral grooves 61 and 62 are related to the pressure to be maintained in the void portion 50 of the rotor shaft support and the lubricity of the bearing metals 18 and 19 with the operating oil. Consideration should be given and appropriate selection may be made if necessary.

The present invention is not limited to the structure of the above-described embodiment, and the shape, structure, etc. of each part of the oil pump 10 can be freely modified or changed. For example, in the above-mentioned embodiment, the spiral grooves 61 and 62 for lubrication are provided on the inner peripheral surfaces of the bearing metals 18 and 19. But,
Not limited to this, the bearing metals 18, 19 may be provided on the outer peripheral surface of the drive shaft 16 in sliding contact. Further, as the oil pump 10 having the above-described configuration, the case of having the variable displacement type pump structure has been illustrated in the above-described embodiment, but the present invention is not limited to this, and the constant displacement widely known from the past. It can be applied even in the form of a pump. The point is that it is a pump having a rotor for sucking and discharging hydraulic oil on the drive shaft, such as a gear pump,
It may be a screw pump or the like. Further, such an oil pump 10 may be applied to various devices and devices other than the power steering device described in the above-described embodiment.

[0036]

EXAMPLE As the oil pump, a vane type in which a cam ring forming a pump cartridge is movably provided in the pump body and the volume of the pump chamber is variable is illustrated. Further, each bearing metal has a single spiral groove formed on its inner peripheral surface.

[0037]

As described above, according to the oil pump of the present invention, the drive shaft having the rotor having the function of sucking and discharging the working oil arranged penetrating the pump body, and the rotor of this drive shaft A pair of bearing metals that rotatably support both axial ends of the
Between the drive shaft and the bearing metal, on the inner peripheral surface of the bearing metal or on the outer peripheral surface of the drive shaft that is in sliding contact with the bearing metal, there is provided a lubricating spiral groove inclined for guiding the working oil to the rotor side. Since it is provided from the rotor-side end to the end opposite to the rotor, the following advantageous effects can be obtained despite the simple configuration.

That is, according to the present invention, leakage of the high pressure hydraulic oil from the pump chamber formed by the rotor escapes from the spiral groove provided in the bearing metal through the rotor shaft support of the drive shaft. By matching the inclination direction of the spiral groove with the rotation direction of the drive shaft, the screw effect in the opposite direction to the conventional one is used to suppress it as much as possible. The amount of oil can be reduced.

In particular, the above-mentioned leaked oil contains a large amount of air bubbles, which are put in a low pressure state in the void portion of the rotor shaft support portion to cause cavitation, but according to the present invention, as described above. Since the amount of leaked oil can be reduced, the occurrence of cavitation due to leaked oil can be suppressed compared to the conventional method, and due to the screw effect of the spiral groove and the rotation direction of the drive shaft, leakage occurs when passing through this spiral groove. It is also possible to eliminate the air bubbles in the oil, which can suppress the occurrence of cavitation and consequently reduce the noise problem caused by this cavitation.

[Brief description of the drawings]

1 shows an embodiment of an oil pump according to the present invention, (a) is a side view and an end view of a bearing metal arranged on the front side of a rotor, and (b) is a bearing arranged on the rear side of a rotor. It is a side view and an end view of metal.

2A and 2B show a case where the rotation direction of the drive shaft is opposite to that of FIG. 1, where FIG. 2A is a side view and an end view of a bearing metal arranged on the front side of the rotor, and FIG. 2B is arranged on the rear side of the rotor. It is the side view and end view of the bearing metal which does.

FIG. 3 is a diagram for explaining the behavior of the hydraulic oil in the groove obtained by the relationship between the inclination direction of the spiral groove and the rotation direction of the drive shaft in the bearing metal that characterizes the present invention.

4 (a), (b), (c), and (d) are views for explaining the flow state of the hydraulic oil in the spiral groove in FIG.

FIG. 5 is a vertical cross-sectional view of a vane type variable displacement oil pump to which the present invention is applied.

6 is a transverse cross-sectional view of a main part of FIG.

7A and 7B are views for explaining a spiral groove in a bearing metal used in a conventional oil pump, in which FIG. 7A is a side view and an end view of the bearing metal arranged on the front side of the rotor, and FIG. It is a side view and an end view of a bearing metal arranged on the rear side.

FIG. 8 shows a case where the rotation direction of the drive shaft is opposite to that of FIG. 7, (a) is a side view and an end view of the bearing metal arranged on the front side of the rotor, and (b) is arranged on the rear side of the rotor. It is the side view and end view of the bearing metal which does.

[Explanation of symbols]

10 ... Vane type variable displacement oil pump, 11 ...
Front body (pump body), 12 ... Rear body (pump body), 13 ... Pump component, 14 ... Storage space, 15 ... Rotor, 15a ... Vane, 16 ... Drive shaft,
17 ... Ball bearing, 17a ... Oil seal, 1
8, 19 ... Bearing metal, 20 ... Cam ring, 20a ... Cam surface, 21 ... Pump chamber, 22 ... Adapter ring, 23 ...
Pressure plate, 25 ... Seal pin, 26 ... Pump discharge side pressure chamber, 27 ... Pump discharge side opening, 28 ... Pump suction port, 28a, 28b, 28c ... Pump suction side passage, 30 ... Control valve, 32 ... Discharge port, 33 ... fluid passage holes, 36, 37 ... first and second fluid pressure chambers, 40 ... variable metering orifice, 41 ... spring, 42 ... plug, 43 ... notch groove, 44 ... passage hole, 47 ... rotor slit , 47a ... Slit base end portion, 48, 49 ... Arc-shaped groove portion, 50 ... Void portion of rotor shaft support portion, 55, 56 ...
Escape passages, 57, 58 ... Voids, 61, 62 ... Spiral grooves.

Claims (4)

[Claims] 1. A drive shaft penetratingly arranged in the pump body, a rotor provided on the drive shaft and rotationally driven in the pump body, and both axial end portions of the rotor of the drive shaft with respect to the pump body. The bearing metal is provided with a pair of bearing metals rotatably rotatably supported, and a spiral groove for lubrication inclined so as to guide the working oil to the rotor side is provided between the drive shaft and the bearing metal. An oil pump provided from the side end to the end on the side opposite to the rotor. 2. The oil pump according to claim 1, wherein a spiral groove for lubrication is provided on the inner peripheral surface of the bearing metal. 3. The oil pump according to claim 1, wherein a spiral groove for lubrication is provided on the outer peripheral surface of the drive shaft that is in sliding contact with the inner peripheral surface of the bearing metal. 4. The oil pump according to claim 1, claim 2, or claim 3, wherein a clearance passage is provided for connecting a gap on the end side of the bearing metal of the pump body on the side opposite to the rotor to a suction side in the pump. The oil pump is characterized by being provided in the pump body.