JP2801932B2 - Vane pump - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a vane pump, and more particularly, to a vane pump structure that reduces pump discharge pulsation to prevent noise.

2. Description of the Related Art In a vane pump, a plurality of pump chambers are formed by partitioning an inner periphery of a cam ring provided outside a rotor in a circumferential direction by vanes projecting from an outer periphery of a rotating rotor. Are sequentially inhaled and compressed and discharged, and are used in a wide range of fields because of their small size, light weight, and high efficiency.

[Problems to be Solved by the Invention] The discharge flow rate of this kind of vane pump pulsates in synchronism with the passage cycle of the vane as shown by a broken line in FIG. 5, and this pulsation pulsates pipes and the like to reduce noise. Cause. Therefore, in order to reduce this pulsation, measures such as changing the cam profile of the cam ring or installing an accumulator have been taken.However, the pulsation reduction is not yet sufficient with the former method, and However, there is a problem that cost increase is large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a vane pump which achieves low noise by effectively reducing discharge pulsation without increasing cost.

[Means for Solving the Problems] To explain the configuration of the present invention, the rotor 1 (FIG. 1, FIG.
A plurality of vanes urged outward in the radial direction are provided at equal intervals on the outer periphery of FIG. 2), and the tips of the vanes 2 are brought into contact with the inner peripheral surface of a cam ring 3 provided outside the rotor 2. Side plates 4, 5 are respectively brought into contact with both end surfaces of each vane 2 to form a pump chamber P closed between the vanes 2, and each pump chamber P is provided through a suction port 51 provided in the side plate 5. The vane pump that sequentially sucks fluid from the pump chamber P and sequentially compresses and discharges fluid from each pump chamber P to the discharge port 52 provided in the side plate 5 includes the suction port 51 of at least one of the side plates.
A pressure relief groove 6 that extends in the moving direction of the vane 2 and is longer than the thickness of the vane end face is formed on the vane side surface between the discharge port 52 and the suction port 51 from the pump chamber P communicating with the discharge port 52. The pressure is released to the connected pump chamber P, and the pressure release groove 6 is formed at the center 61 thereof (FIG. 3, FIG.
(FIG. 4) The cross section of the groove is reduced.

[Operation] In the vane pump having the above-described configuration, a part of the fluid from the high-pressure pump chamber P communicating with the discharge port 52 flows out to the low-pressure pump chamber P communicating with the suction port 51 by the pressure relief groove 6. Thus, an increase in the discharge fluid pressure is suppressed, and pulsation is reduced. Since the pressure relief groove 6 has a small groove cross-section at its central portion 61, the amount of fluid flowing out when the vane end face passes through this portion is appropriately suppressed, and the discharge fluid pressure is excessively reduced. Is prevented.

[Embodiment] In FIG. 2, the pump housing is composed of a first housing 4 also serving as one side plate and a second housing 7 abutted against the first housing 4, and the center of the first housing 4 has a bearing 81 and a bearing. The rotating shaft 8 is supported by the metal 82. The circular rotor 1 is disposed in the second housing 7 and connected to the tip of the rotating shaft 8 by a spline. A large number of vanes 2 are provided at equal intervals on the outer periphery (a chain line in FIG. 1). Each vane 2 is inserted into a groove formed in the radial direction of the rotor 1 so as to be able to advance and retreat, and receives a part of the discharge pressure at its base end and is urged to advance.

A cam ring 3 is provided outside the rotor 1, and the tip of each of the vanes 2 has an elliptical inner peripheral surface (first
(Dashed line in the figure). Both end surfaces of each vane 2 are in contact with the abutting surface of the first housing 4 and the side plate 5 provided in the second housing 7, and the space between the rotor 1 and the cam ring 3 is circumferentially formed by the vane 2. A plurality of pump chambers P (FIG. 1) are partitioned in the direction.

These pump chambers P gradually increase or decrease in volume every 90 degrees of the rotation of the rotor 1, and the suction port is provided on the abutting surface of the first housing 4 and the plate surface of the side plate 5 corresponding to the portion where the pump chamber volume gradually increases. 51 (the first housing 4 is not shown) is formed, while discharge ports 42 and 52 are formed on the abutment surface of the first housing 4 and the plate surface of the side plate 5 corresponding to the gradually reduced portion.

Thus, the fluid that has reached each of the suction ports 51 via the suction passage 71 is sucked into the pump chamber P whose volume gradually increases, and is subsequently discharged to each discharge port 52 from the pump chamber P whose volume gradually decreases. Then, it is sent to an external device via the discharge passage.

When the vane pump operates, the discharge port 52
Fluid pressure peaks at every rotor rotation angle equal to the pane pitch and pulsates greatly. This is indicated by the dashed line in FIG.

Therefore, in the present embodiment, the plate surface of the side plate 5 (first
A pressure relief groove 6 is provided substantially at an intermediate position of a vane moving region from the suction port 51 to the discharge port 52 in FIG.
The details will be described with reference to FIGS. 3 and 4. The pressure relief groove 6 is formed to be elongated with a constant width in a direction connecting the suction port 51 and the discharge port 52, and the depth of the groove is reduced only in the central portion 61. The remaining part is a deeper constant depth. When the end face of the vane 2 passes over the pressure relief groove 6 in the direction of the white arrow in FIG.
The pressure in the preceding pump chamber P1 communicating with the suction port 51 is high, and the pressure in the subsequent pump chamber P2 communicating with the suction port 51 is low. Then, the fluid flows out from the high-pressure pump chamber P1 to the low-pressure pump chamber P2 via the pressure relief groove 6 (arrow in the figure), and the discharge port 52
The increase in fluid pressure at is suppressed.

In this case, assuming that the entire pressure relief groove 6 has the same depth, when the vane 2 reaches near the center of the pressure relief groove 6, the pump chamber
The cross-sectional area of the flow path from P1 to the pump chamber P2 may be maximized, the amount of fluid flowing out may be excessive, and the fluid pressure of the discharge port 52 may be excessively reduced. This is indicated by the chain line in FIG. In this state, although the temporary pulsation is suppressed, the secondary or tertiary pulsation is rather increased, and noise due to such pulsation may become a problem.

Therefore, in the present embodiment, as described above, the central portion 61 of the pressure relief groove 6 is formed shallow, and the groove cross-sectional area of this portion is reduced, so that the fluid outflow amount is appropriately limited.
The discharge port fluid pressure does not excessively decrease (solid line in FIG. 5), and not only primary pulsation but also secondary and higher pulsations are suppressed to a small extent, and pump noise is effectively reduced.

[Other Embodiments] The shape of the pressure relief groove 6 is not limited to that of the above-described embodiment, and the shape of the pressure relief groove 6 may be adjusted so as to obtain an optimal fluid outflow amount accompanying the movement of the vane 2.
As shown in FIG. 7 to FIG. 7, the groove bottom surface can be an appropriate curved surface which becomes shallow at the central portion 61, and as shown in FIG. You can do it.

Further, as shown in FIGS. 9 and 10, the pressure relief groove 6 is entirely formed at the same depth, and both side walls of the central portion 61 are projected inward to reduce the groove cross section at this portion. It can also be structured.

The pressure relief groove 6 may be provided on the abutment surface of the first housing 4 facing the side plate 5, or may be provided on both of them. Further, the pressure relief groove 6 may be provided on the way from the discharge port 52 to the suction port 51.

[Effects of the Invention] As described above, the vane pump of the present invention is provided with the pressure relief groove for allowing a part of the fluid to flow out of the pump chamber communicating with the discharge port to the pump chamber communicating with the suction port, thereby providing a primary pump discharge pressure. Along with suppressing pulsation, the pressure relief groove prevents the fluid outflow from becoming excessive by reducing the groove cross section at the center thereof, thereby preventing the occurrence of secondary or higher pulsation of the pump discharge pressure. This effectively reduces pump noise.

[Brief description of the drawings]

1 to 5 show an embodiment of the present invention, wherein FIG. 1 is a front view of an abutting surface of a pump housing, FIG. 2 is an overall vertical sectional view of the pump, and FIG. FIG. 4 is a sectional view taken along line IV-IV of FIG. 3, FIG. 5 is a view showing a pressure fluctuation of the discharge fluid, and FIGS. 6 to 8 are longitudinal sections showing other examples of the pressure relief groove. 9 and 10 show still another example of the pressure relief groove, FIG. 9 is a longitudinal sectional view thereof, and FIG.
It is a B arrow view of the figure. 1 ... rotor 2 ... vane 3 ... cam ring 5 ... side plate 51 ... suction port 52 ... discharge port 6 ... pressure relief groove 61 ... central part P, P1, P2 ... pump chamber

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-3281 (JP, A) JP-A-60-201089 (JP, A) Jpn. Open 63-104689 (JP, U) (58) Field (Int.Cl. ⁶ , DB name) F04C 2/30-2/352 F04C 18/30-18/352 F04C 15/04

Claims (1)

(57) [Claims] 1. A plurality of vanes urged radially outward on an outer periphery of a rotor are provided at equal intervals, and tips of the vanes are brought into contact with an inner peripheral surface of a cam ring provided on an outer side of the rotor. At the same time, a side plate is brought into contact with both end surfaces of each vane to form a closed pump chamber between the vanes, and a fluid is sequentially sucked into each pump chamber from a suction port provided in the side plate. In a vane pump for sequentially compressing and discharging a fluid from a pump chamber to a discharge port provided in the side plate, at least one of the side plates has a vane-side surface between the suction port and the discharge port in a moving direction of the vane. A pressure relief groove that extends and is longer than the thickness of the end face of the vane is formed to release pressure from the pump chamber communicating with the discharge port to the pump chamber communicating with the suction port. Uninashi and the pressure relief groove vane pump, characterized in that no small groove cross-section at its central portion.