JP2000205159A - Vane type vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent the breakage of a vane by the reverse rotation of a vacuum pump, in a vane type vacuum pump suitably used for a vacuum booster for motor vehicle, by providing a pressure reducing means in a displacement chamber which is abnormally raised in pressure when the vacuum pump is reversely rotated. SOLUTION: When an engine is operated to rotate a rotor 3 through a rotating shaft 1, displacement chambers 11a-11c are changed in volume according to the rotation of the rotor 3, and the air sucked through an intake port 6 and lubricating oil are discharged through a discharge port 9. In this case, a pressure rising preventing groove 12 for storing or releasing the lubricating oil or air is formed on the casing 5 or plate 8 located in a space (chamber) 11a formed between the minimum clearance part between the inside surface of the casing 5 and the outside surface of the rotor 3 and the intake port 6 located in the position of about the angle of 360 deg./the number of vanes in the normal rotating direction on the basis of the minimum clearance part. According to this, pressure rising within the space 1a in the reverse rotation of the vacuum pump can be reduced to prevent the breakage of the vanes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vane vacuum pump used as an operating pressure source for a vacuum booster of an automobile or the like.

[0002]

2. Description of the Related Art A vane vacuum pump is often used as an operating pressure source for a vacuum booster of an automobile. In the vane vacuum pump, a rotor provided with a plurality of radial grooves in the radial direction is eccentrically arranged in a substantially cylindrical casing. A vane is slidably held in the radial groove of the rotor so as to be able to reciprocate in the radial direction of the rotor, and a plurality of chambers are formed by sliding one end of the vane against the inner peripheral surface of the casing. The plurality of chambers are mainly formed by the inner peripheral surface of the housing, the outer peripheral surface of the rotor, and the vanes. This room is called a displacement room. The displacement of the displacement chamber is changed by the rotation of the rotor, and the expansion and compression processes of air are repeated to act as a vacuum pump. Such a vane type vacuum pump is described in Japanese Patent Application Laid-Open Nos. 1-170783 and 7-49094.

[0003]

There is no problem when the vane type vacuum pump is rotating in the normal rotation direction. However, when the vane type vacuum pump is rotated in the opposite direction (reverse rotation direction) to the normal rotation direction, the pressure in a specific displacement chamber is increased. Abnormal boost. The abnormal pressure increase is formed between a minimum clearance between the inner peripheral surface of the casing and the outer peripheral surface of the rotor and a suction port located at a position near an angle of 360 degrees / vane number in the normal rotation direction based on the minimum clearance. It occurs because the air and lubricating oil accumulated in the displacement chamber are compressed. If the pressure in the displacement chamber is abnormally increased, the vane may be damaged.

An object of the present invention is to provide a vane type vacuum pump capable of reliably preventing vane breakage even when the vacuum pump rotates in the reverse direction.

[0005]

A feature of the present invention is that a pressure reducing means is provided in a displacement chamber which abnormally raises the pressure when the vacuum pump rotates in the reverse direction.

The pressure reducing means according to the present invention has a function of reducing the pressure to a pressure at which the vanes forming the abnormally raised displacement chamber are not damaged.

In the present invention, the pressure in the displacement chamber, which is abnormally increased during the reverse rotation, is reduced by the pressure reducing means, so that the vane can be prevented from being damaged.

[0008]

1 and 2 show an embodiment of the present invention. FIG. 2 is a partially sectional view taken along the line AA 'of FIG.

In FIG. 1 and FIG.
It is rotatably supported by a and 2b. A rotor 3 is fitted on the rotating shaft 1. The rotor 3 is provided with a plurality of radial grooves in its radial direction, and the plurality of (three in the figure) vanes 4 are slidably held by the radial grooves.
The vane 4 can reciprocate in the rotor radial direction, and one end thereof is in sliding contact with the inner peripheral surface of the casing. The rotor 3 is eccentrically accommodated in a casing 5 having a substantially cylindrical shape. The open end surface of the casing 5 is closed by a plate 8, and the contact surfaces of both are sealed by an O-ring 7. Casing 5
Is provided with a suction port 6 for sucking air from inside a device such as a master bag of an automobile (not shown) into the casing 5. The plate 8 has an oil supply hole 8a for introducing lubricating oil for lubricating the rotation and sliding of the rotor 3 and the vane 4 into the casing 5. Lubricating oil is pumped into the oil supply hole 8a from an engine (not shown). The lubricating oil that has entered the casing 5 is rotated by the regular rotation together with the air sucked through the suction port 6 or the plate 8.
Is discharged to the engine side through a discharge port 9 provided in the engine. A gear 10 for transmitting the power of the engine is attached to an end of the rotating shaft 1, and the rotating shaft 1 is driven by the rotation of the engine, so that the rotor 3 rotates. Spaces (displacement chambers) 11a, 11b formed by the rotor 3, the vane 4, the casing 5, and the plate 8 inside the casing 5,
11c changes its volume by the rotation of the rotor 3, and acts as a vacuum pump. When the rotation direction in which air and lubricating oil sucked in from the suction port 6 are discharged from the discharge port 9 by the rotation of the rotation shaft 1 is the normal rotation direction, the casing 5 rotates in the anti-normal rotation direction (reverse rotation direction). Formed between the inner peripheral surface of the rotor 3 and the inlet 6 located at a position near an angle of 360 degrees / vane number in the normal rotation direction based on the minimum clearance between the outer peripheral surface of the rotor 3 and the minimum clearance. Room)
The lubricating oil and air in 11a are compressed and pressurized.

According to the present embodiment, the position is in the vicinity of an angle of 360 degrees / vane number in the normal rotation direction from the minimum clearance between the inner peripheral surface of the casing 5 and the outer peripheral surface of the rotor 3 with reference to the minimum clearance. Space (chamber) 1 formed between suction port 6
A groove 12 for storing or releasing lubricating oil or air is provided in the casing 5 or the plate 8 in 1a. Therefore, even if the space 11a rotates in the reverse rotation direction,
Internal pressure rise can be reduced, and vane damage can be prevented. Further, since the groove 12 is provided integrally with the casing 5, it is inexpensive without increasing the number of parts.

FIGS. 3 and 4 show another embodiment of the present invention.
4 is a partially sectional view taken along the line BB 'of FIG.

In FIGS. 3 and 4, a part or all of the relief is provided in an angle range of 360 ° / number of vanes in the normal rotation direction based on the minimum clearance between the inner peripheral surface of the casing 5 and the outer peripheral surface of the rotor 3. A hole 13A is provided in the plate 8. A valve mechanism 15 is provided at the opening on the outer side of the relief hole 13A.
Is provided. The valve mechanism 15 is a valve 15 housed in a cylindrical housing part 14 formed integrally with a part of the plate 8.
a, a spring 16 for pressing the valve 15a against the bottom surface of the storage portion 14, a retainer 17 for holding the spring 16 and guiding the movement of the valve mechanism 15 , and a holder 18 for holding the retainer 17. Even in this manner, abnormal pressure increase in the chamber 11a can be prevented. Also, by providing both the groove 12 and the valve mechanism 15 as in the embodiment shown in FIG. 1, even when the vacuum pump is stopped, intrusion of air, lubricating oil, water, etc. from the outside is prevented, and rotation in the reverse rotation direction is performed. When the pressure inside the space 11a becomes equal to or higher than a predetermined pressure, the space 11a can be discharged from the inside, and the reliability can be further improved.

FIG. 5 shows a modification of the embodiment shown in FIG.
Of the components constituting the valve mechanism 15 , a part or all of the open end of the cylindrical storage part 14 is swaged in place of the holder 18 for holding the retainer 17, whereby the retainer 1 is formed.
7 is held at the open end of the cylindrical storage section 14. In this way, the number of parts can be reduced.

FIGS. 6 and 7 show another embodiment of the present invention.
7 is a partially sectional view taken along the line CC 'of FIG.

[0015] Figure 6, the embodiment shown in FIG. 7 is a valve mechanism 15
Is provided with a connector 19 to which a hose (not shown) for introducing air and lubricating oil discharged from the inside of the casing 5 to the outside can be attached. In this way, air and lubricating oil can be guided to the engine side through the hose,
The present invention can be applied to a vacuum pump in which air and lubricating oil discharged from the relief hole 13B to the outside cannot be directly discharged to the engine side.

[0016]

According to the present invention, even when the rotating shaft of the vacuum pump rotates in the reverse direction to the normal rotation, the pressure inside the specific displacement chamber can be prevented, so that the vane can be reliably prevented from being damaged. As a result, there is an effect that a highly reliable vacuum pump can be provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention.

FIG. 2 is a partially sectional view taken along the line AA 'of FIG.

FIG. 3 is a longitudinal sectional view showing another embodiment of the present invention.

FIG. 4 is a partially sectional view taken along the line BB ′ of FIG. 3;

FIG. 5 is a longitudinal sectional view showing a modification of the embodiment shown in FIG. 3;

FIG. 6 is a longitudinal sectional view showing another embodiment of the present invention.

FIG. 7 is a partially sectional view taken along the line CC ′ of FIG. 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotating shaft, 2a, 2b ... Bearing, 3 ... Rotor, 4 ... Vane, 5 ... Casing, 6 ... Suction port, 8 ... Plate, 8a
... refueling hole, 9 ... discharge port, 11a, 11b, 11c ... space (displacement chamber), 12 ... pressurization prevention groove, 13 ... relief hole, 15 ... valve mechanism.

Continued on the front page (72) Inventor Kazuo Horioka 2520 Oita Takaba, Hitachinaka-shi, Ibaraki Co., Ltd.Automotive Equipment Division, Hitachi, Ltd. (72) Inventor Tohru Muraishi 3-20-30 Shinnakazato, Yono-shi, Saitama Prefecture Inside Miwa Seiki Co., Ltd. (72) Tadao Endo 3--20-30 Shinnakazato, Yono-shi, Saitama Miwa Seiki F term in the company (reference) 3H029 AA05 AA15 AA21 AB02 AB06 BB38 BB47 BB59 CC03 CC06 CC13 CC23 3H040 AA08 BB01 BB07 BB11 CC20 DD01 DD21 DD26

Claims (5)

[Claims] 1. A rotor having a substantially cylindrical bottomed casing, a rotor disposed eccentrically inside the casing, and having a plurality of radial grooves provided in a radial direction thereof, and a rotor diameter provided in the radial grooves of the rotor. And a plurality of vanes forming one or more chambers, one end of which is in sliding contact with the inner peripheral surface of the casing, and a rotating shaft that rotationally drives the rotor. A suction port for introducing air into the plurality of chambers, a lubrication hole for taking lubricating oil into the casing, and a discharge port for discharging air sucked from the suction port and lubricating oil taken from the lubrication hole. A vane type vacuum pump provided with a pressure reducing means in the chamber which abnormally raises the pressure when the rotor rotates in the reverse direction. 2. A vane type vacuum pump according to claim 1, wherein said pressure reducing means is a groove provided on an inner peripheral surface of said casing. 3. A casing according to claim 1, further comprising a plate abutting on an open end of said casing, wherein said pressure reducing means forms a release hole in said casing or said plate forming said chamber which abnormally raises the pressure when said rotor rotates in a reverse direction. And a valve mechanism for opening only one direction from the inside of the casing to the outside in the release hole. 4. A vane-type vacuum according to claim 1, wherein said pressure reducing means has a function of reducing the pressure to a pressure at which said vanes forming said chamber which abnormally raises in pressure when said rotor rotates in the reverse direction are not damaged. pump. 5. A vane type vacuum pump according to claim 1, wherein said pressure reducing means includes both the groove according to claim 2 and a release hole having a valve mechanism according to claim 3.