JP2016133019A - Vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum pump for actualizing the improvement of its suction performance and a reduction in its driving torque.SOLUTION: A vane pump (the vacuum pump) includes a housing having a pump chamber, a rotor 3 having an outer peripheral face which rotates in the state of contacting the inner peripheral face of the pump chamber, and a vane supported by the rotor 3 for partitioning the pump chamber into a plurality of working spaces including a negative pressure chamber and a compression chamber with the rotation of the rotor 3. Into the pump chamber, lubricating oil is supplied. The rotor 3 has communication grooves 3G communicating the compression chamber with the negative pressure chamber. The communication grooves 3G are each provided in the range of a predetermined angle around the axis of the rotor 3 from a contact part 3H of the outer peripheral face of the rotor 3 in the compression chamber with the vane in the direction of the negative pressure chamber.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a vacuum pump, and more particularly to a structure of a rotor of a vacuum pump.

  Conventionally, there is a vane pump used as a vacuum pump for an automobile (see Patent Document 1). In a general vane pump, a rotor is provided eccentrically in a substantially circular pump chamber, and the vane is supported by a slit formed in the radial direction of the rotor. The vane is slidably supported with respect to the slit of the rotor, and both ends thereof are configured to be kept in contact with the inner peripheral surface of the pump chamber. And the function as a vacuum pump is expressed by expanding / contracting the volume of the working space in the pump chamber divided by the vane and the rotor by rotating the rotor.

JP 2012-67730 A

  Lubricating oil is supplied to the pump chamber, but recently, there is a tendency to reduce the amount of lubricating oil supplied to improve fuel efficiency. However, if the amount of lubricating oil in the pump chamber is reduced, the lubricating oil cannot serve as a seal that seals the working space, resulting in a problem that the suction performance decreases. In addition, the original lubricating performance of the lubricating oil cannot be exhibited, and there is a problem that the driving torque increases.

  Further, the configuration of the conventional vane pump has a problem that the driving torque increases when air is compressed in the pump chamber.

  Then, in view of the subject which concerns on this invention, an object of this invention is to provide the vacuum pump which implement | achieves improvement of suction performance and reduction of drive torque.

  The present invention includes a housing having a pump chamber, a rotor having an outer peripheral surface that rotates in contact with the inner peripheral surface of the pump chamber, a rotor supported by the rotor, and the pump chamber becoming negative as the rotor rotates. In a vacuum pump that includes a vane that is partitioned into a plurality of working spaces including a pressure chamber and a compression chamber, and in which lubricating oil is supplied into the pump chamber, the rotor communicates with the compression chamber and the negative pressure chamber. It has a passage.

  In the above vacuum pump, the communication path may be a communication groove provided on an outer peripheral surface of the rotor.

  Further, in the above vacuum pump, the communication groove is provided at a predetermined angle from the contact portion of the outer peripheral surface of the rotor in the compression chamber with the vane toward the negative pressure chamber about the rotor axis. be able to.

  According to the present invention, it is possible to improve the suction performance of the vacuum pump and reduce the driving torque by providing the communication path in the rotor.

It is a top view of the vane pump in one embodiment of the present invention. It is the sectional view on the AA line of FIG. It is a perspective view of the rotor in one embodiment of the present invention. It is a top view of the rotor in one embodiment of the present invention.

  A vane pump which is an embodiment of the vacuum pump of the present invention will be described with reference to FIGS. 1 and 2. The vane pump 1 is fixed to the side surface of the engine room, for example, and functions as a negative pressure source of the brake booster.

  The vane pump 1 is provided with a stepped cylindrical housing 2 having a substantially circular pump chamber 2A, a pump chamber 2A, and a pump chamber 2A which is disposed in the pump chamber 2A and whose axis is eccentric with respect to the center of the pump chamber 2A. The rotor 3 having an outer peripheral surface that rotates while being in contact with the inner peripheral surface of the motor, and is disposed in the pump chamber 2A and rotated in the direction of the arrow shown in FIG. A vane 4 partitioned into a space and a cover 5 that closes an opening of the large-diameter portion 2B in the housing 2, that is, one end opening of the pump chamber 2A are provided. In FIG. 1, the working space is divided into a positive pressure chamber 2a, a negative pressure chamber 2b, and a compression chamber 2c.

  The housing 2 has a large-diameter portion 2B whose inside is the pump chamber 2A, a medium-diameter portion 2C formed at a position adjacent to the end surface of the large-diameter portion 2B, and a small-diameter portion 2D that is adjacent to the medium-diameter portion 2C. The rotor 3 is rotatably supported by the inner peripheral surfaces of the medium diameter portion 2C and the small diameter portion 2D. The large-diameter portion 2B of the housing 2 is provided with a suction passage 6 for sucking gas (air) from the brake booster to the pump chamber 2A, and upstream of the suction passage 6, the brake booster A check valve 9 for maintaining a negative pressure is provided.

  Further, an axial through-hole penetrating from the pump chamber 2A to the end face of the housing 2 is formed in the middle diameter portion 2C adjacent to the lowermost portion of the pump chamber 2A, and this through-hole is formed from the pump chamber 2A to the housing. 2 is a discharge passage 7 for discharging gas to the outside. A reed valve 8 that opens and closes the discharge passage 7 when necessary is provided on the end surface of the housing 2.

  A guide groove 3A in the diameter direction is formed at one end of the rotor 3 in the pump chamber 2A in the axial direction, and a plate-like vane 4 is slidably attached to the guide groove 3A in the diameter direction. Caps 4 </ b> A that slide on the inner peripheral surface of the pump chamber 2 </ b> A are attached to both ends of the vane 4. As shown in FIG. 1, when the rotor 3 and the vane 4 are rotated in the direction of the arrow, both caps 4A slide while maintaining airtightness with the inner peripheral surface of the pump chamber 2A, and the axial direction of the vane 4 Both end surfaces 4B and 4B slide with the inner wall surface of the cover 5 and the inner wall surface of the pump chamber 2A, and a part of the outer peripheral surface of the rotor 3 is maintained in contact with the inner peripheral surface of the pump chamber 2A. . Thereby, the inside of the pump chamber 2A is divided into a positive pressure chamber 2a, a negative pressure chamber 2b, and a compression chamber 2c that can be expanded and contracted.

  An oil supply passage 11 is formed across the shaft portion on the other end side of the rotor 3 and the inner peripheral surface of the housing 2. The oil supply passage 11 is drilled in the shaft portion of the rotor 3 and is connected to the oil supply pipe 12, the diameter direction hole 3 </ b> C continuous from the other end of the axial direction hole 3 </ b> B, and the rotor 3. When rotating in the direction of the arrow, it is composed of an axial groove 2E of the housing 2 that intermittently communicates with the diameter direction hole 3C.

  When the engine is driven, the rotor 3 and the vane 4 are rotated in the direction of the arrow in FIG. 1 in conjunction with the driving of the engine, so that the volumes of the three working spaces 2a to 2c are expanded and contracted. Accordingly, the gas (air) in the brake booster is sucked into the negative pressure chamber 2b through the suction passage 6 and the gas in the positive pressure chamber 2a is discharged into the discharge passage 7 and the opened lead. It is discharged through the valve 8 into the engine room, which is outside the pump chamber 2A.

  Further, when the rotor 3 and the vane 4 are rotated as described above, the lubricating oil is supplied to the sliding portion of the pump chamber 2 </ b> A and the vane 4 through the oil supply passage 11. The lubricating oil flowing into the pump chamber 2A is primarily stored in the lower portion of the pump chamber 2A and then moved by the rotating vane 4 and its cap 4A, and then the discharge passage 7 and the open reed valve 8 are opened. It is discharged into the engine room that is outside the pump chamber 2A.

  Next, the structure of the rotor 3 will be described in detail with reference to FIGS. The shaft portion of the rotor 3 is formed in a stepped shape in which a large-diameter first shaft portion 3D, a medium-diameter second shaft portion 3E, and a small-diameter third shaft portion 3F are connected.

  In the first shaft portion 3D, guide grooves 3A are formed, and communication grooves 3G are formed at two locations on the outer peripheral surface. The communication groove 3G has a U-shaped axial cross section, and can be formed by cutting or the like. The communication groove 3G is centered on the axis of the rotor 3 from the contact portion 3H, which is a portion in contact with the vane 4 on the outer peripheral surface of the first shaft portion 3D, toward the negative pressure chamber 2b (direction away from the vane 4 along the outer peripheral surface). Is provided only at a predetermined angle θ (see FIG. 4). In FIG. 3, the communication groove 3 </ b> G extends linearly in the horizontal direction, but may be oblique or curved as long as it is along the outer peripheral surface.

  With such a configuration, part of the lubricating oil supplied into the pump chamber 2A is stored in the communication groove 3G when the rotor 3 and the vane 4 are rotated. And the compression chamber 2c is formed in the state as shown in FIG. 1, and the compression chamber 2c and the negative pressure chamber 2b are communicated by the communication groove 3G. At this time, the lubricating oil stored in the communication groove 3G is discharged (released) into the negative pressure chamber 2b due to the pressure difference between the compression chamber 2c and the negative pressure chamber 2b.

  As a result, the pressure in the compression chamber 2c decreases and the driving torque of the rotor 3 is reduced. In addition, a part of the lubricating oil supplied into the pump chamber 2A is stored in the communication groove 3G before being discharged from the discharge passage 7 and supplied to the negative pressure chamber 2b, so that the lubricating oil is regenerated in the pump chamber 2A. Since it is used, a sufficient amount of lubricating oil can be secured to exert the lubricating performance, and the driving torque is reduced. Further, the lubricating oil sufficiently plays a role as a seal that seals the working space, and the suction performance is improved.

  According to another aspect, the amount of lubricating oil supplied to the pump chamber 2A can be reduced. As a result, even if the amount of lubricating oil supplied into the pump chamber 2A is reduced for the purpose of improving fuel efficiency, the amount of lubricating oil necessary for the operation of the vane pump 1 can be secured, so that the driving torque can be suppressed. The lubricating oil can also serve as a seal that seals the working space and maintain suction performance.

  In order to achieve the above-described effects, the predetermined angle θ needs to be an angle at which the compression chamber 2c and the negative pressure chamber 2b can communicate with each other. On the other hand, if the predetermined angle θ is too large, not only the lubricating oil but also air escapes to the negative pressure chamber 2b, and the operation efficiency decreases. In addition, if the predetermined angle θ is too large, the positive pressure chamber 2a and the negative pressure chamber 2b communicate with each other before the compression chamber 2c is formed, and the operation efficiency is lowered. Considering these, for example, in the vane pump 1 of the present embodiment, it is preferable that θ is around 30 °.

  In the above-described embodiment, one end of the communication groove 3G is provided to the contact portion 3H. However, a shape provided to the vicinity of the contact portion 3H may be used. In the above embodiment, the cross section in the axial direction of the communication groove 3G is U-shaped, but the cross-sectional shape is not limited, and may be, for example, U-shaped or V-shaped. In addition, the vertical width, vertical position and depth of the communication groove 3G can be appropriately designed in consideration of the amount of lubricating oil. Further, the number of the communication grooves 3G is not limited, and a plurality of grooves may be formed in consideration of the width and depth of the communication grooves 3G.

  In the above embodiment, the communication groove 3G is used, but a communication path other than the groove shape may be used as long as the compression chamber 2c and the negative pressure chamber 2b can communicate with each other. For example, it may be a through hole or the like having openings at both ends of the communication groove 3G. Also in this case, the same effect as that of the communication groove 3G can be obtained.

1 Vane pump (vacuum pump)
2 Housing 2A Pump chamber 2b Negative pressure chamber 2c Compression chamber 3 Rotor 3A Guide groove 3G Communication groove (Communication channel)
3H contact 4 vane

Claims (3)

A housing having a pump chamber;
A rotor having an outer peripheral surface that rotates in contact with the inner peripheral surface of the pump chamber;
A vane that is supported by the rotor and divides the pump chamber into a plurality of working spaces including a negative pressure chamber and a compression chamber as the rotor rotates,
In a vacuum pump in which lubricating oil is supplied into the pump chamber,
The vacuum pump according to claim 1, wherein the rotor has a communication passage that communicates the compression chamber and the negative pressure chamber.   The vacuum pump according to claim 1, wherein the communication path is a communication groove provided on an outer peripheral surface of the rotor.   3. The communication groove according to claim 2, wherein the communication groove is provided at a predetermined angle about the axis of the rotor from a contact portion of the outer peripheral surface of the rotor in the compression chamber with the vane toward the negative pressure chamber. Vacuum pump.

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