JPH02169883A - Vane pump - Google Patents

Abstract

PURPOSE:To reduce the fluctuation of the discharge flow at a low cost by communicating a compression side pump chamber communicated to a discharge port partitioned by vanes and a low-pressure side pump chamber communicated to a suction port with a pressure relief groove across the vane. CONSTITUTION:A compression side pump chamber 30b and a low-pressure side pump chamber 30c partitioned between vanes 40 immediately before a discharge port 1c in the rotation direction of a rotor 30 are provided on opposite faces of a housing 1 provided with a discharge chamber 1g. Both pump chambers 30b and 30c are communicated by a pressure relief groove 50 communicated across the vane 40. When the vane 40 is located directly before the discharge port 1c immediately before the completion of the suction stroke, the compression side pump chamber 30b and the low-pressure side pump chamber 30c behind the vane 40 are communicated by the relief groove 50. Part of the pressure of the compression side pump chamber 30b is forcibly relieved to the low-pressure side pump chamber 30c, the pressure pulsation is reduced, and the discharge flow fluctuation is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a vane pump that sucks in and discharges liquid such as oil.

<Prior Art> A cam ring housed in a pump housing, a rotor rotating inside the cam ring, and a rotor that slides in the radial direction within a vane chamber provided radially on the rotor and slides into contact with the cam surface of the cam ring. A vane pump that has a plurality of vanes, increases or decreases the volume of each pump chamber partitioned between the vanes as the rotor rotates, sucks in liquid from a suction port, and discharges it from a discharge port is well known.

<Problems to be Solved by the Invention> The discharge flow rate of this type of vane pump varies depending on the shape of the cam curve provided in the cam ring, internal leakage, etc. In order to reduce this variation, pump design
Efforts include changing the shape of the cam curve.

However, by changing the cam curve, the fluctuation of the discharge flow rate changes, and although it is possible to design a pump with small fluctuations to a certain extent, there is a limit to this, and this flow fluctuation is
The discharge pressure fluctuates as shown by the solid line in the figure, and the resulting pressure pulsations become a source of vibration and noise in the pump and piping.

There are also examples in which an accumulator is attached to reduce pressure pulsations, but in this case, the cost of the system increases.

Means for Solving the Problems> The present invention has been made to solve the above-mentioned problems, and its characteristic configuration is a cam ring housed in a pump housing, and an internal structure of the cam ring. The pump has a rotor that rotates, and a plurality of vanes that slide in the radial direction within a vane chamber provided radially on the rotor and that slide in contact with the cam surface of the cam ring, and each pump is partitioned between the vanes as the rotor rotates. In a vane pump that increases or decreases the volume of a chamber to suck in liquid from a suction port and discharge it from a discharge port, a compression side pump chamber that communicates with the discharge port separated by the vane between the discharge port and the suction port, and a low pressure that communicates with the suction port. A pressure relief valve is provided that communicates with the side pump chamber across the side of the vane.

With the above configuration, a part of the pressure in the compression side pump chamber leading to the discharge port is actively released from the pressure relief groove to the low pressure side pump chamber leading to the suction port, and pressure pulsation is suppressed by suppressing the pressure waveform. Make smaller. This provides a pumping action with small fluctuations in discharge flow rate.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. In FIG. 1, 1 is a first pump housing that supports a rotating shaft 31, and 2 is a second pump housing that houses a cam ring 25, a rotor 30, a vane 40, a side plate 21, and the like.

This first pump housing 1 and second pump housing 2
, the contact surface 1a on the first pump housing 1 side and the contact surface 2a on the second pump housing 2 side are in contact with each other, and the bolt 22
It is tightened and fixed. 23 is the contact surface 1a,
This is a sealing material between 2a.

The rotating shaft 31 is rotatably supported by the first pump housing 1 via a bearing 11 and a bearing metal 12. 13 is a sealing material provided around the rotating shaft 31 between the bearing 11 and the bearing metal 12.

As shown in FIG. 2, the first pump housing 1 has a discharge port IC5 and a suction port 1f opened on the contact surface 1a, and an annular discharge chamber 1 communicating with the discharge port 1C.
g, a flow control valve 1b communicating with the discharge chamber 1g, a supply passage or bypass passage 1d communicating with the suction port 1f, and a reservoir port 1e communicating with the supply passage or bypass passage 1d. .

On the other hand, inside the second pump housing 2, as shown in FIG. Contact surface 1a of pump housing 1
A cam ring 25 is interposed and fixed between.

A rotor 30 fixed to the rotating shaft 31 is rotatably disposed within the cam ring 25, and vanes 40 are disposed slidably in the radial direction within vane chambers provided radially in the rotor 30. The tips of the vanes 40 are in sliding contact with the cam surface of the cam ring 25, and as the rotor 30 rotates, the volume of each pump chamber 30a partitioned between the vanes 40 is increased or decreased.

The side plate 21 also has a suction port 2f opened in the same phase as the suction port 1f on the first pump housing 1 side, and a discharge port 2C opened in the same phase as the discharge port '1 (l).

Further, a pressure chamber 2b is formed between the side plate 21 and the second pump housing 2 and communicates with the discharge port 2C. 24 is a passage communicating with the pressure chamber 2b. 52 is a back pressure groove provided in the first pump housing 1, and 53 is a back pressure groove provided in the side plate 21.

A portion of the discharge pressure introduced into the pressure chamber 2b causes the side plate 21 to be damaged by the cam ring 25 and the rotor 300!
! I and the pressure introduced into the back pressure grooves 52 and 53 acts to push the vane 40 up.

In the vane pump as described above, the present invention provides a discharge port 1C in the rotational direction of the rotor 30 on the facing surface of the first pump housing 1 in which the discharge chamber 1Q is provided, as shown in FIGS. 2 and 4. Immediately before the vane pump, a pressure relief pipe 50 is provided which communicates the compression side pump chamber 30b and the low pressure side pump chamber 30c, which are partitioned between the vanes 40, across the side surface of the vane pump.

Since the present invention has the above-described structure, as shown in FIG.
When the vane 40 is positioned just before the pressure relief extinguisher 5
0 communicates the compression side pump chamber 30b in front of the vane 40 and the low pressure side pump chamber 31C after the vane 40 by straddling the side surface of the vane 40. Therefore, a part of the pressure in the compression side pump chamber 30b is forcibly relieved to the low pressure side pump chamber 30c through the pressure relief fluid 50, as shown by the arrow. As a result, the peak of the pressure waveform generated at point A in Figure 5, which occurs for each vane pitch, becomes smaller as shown by the dotted line.
Pressure pulsations are reduced. The pressure pulsation with respect to the rotational speed of the bob is reduced from the conventional state shown by the solid line to state B shown by the dotted line, as shown in FIG. The pressure relief extinguisher 50' may be provided while the vane 40 moves from the discharge port 1c to the suction port 1f as shown by the two-dot chain line in FIG. 3. In this case, the pressure pulsation with respect to the pump rotation speed is , 6th
As shown in the figure, the conventional state shown by the solid line is reduced to the state shown by the dotted chain line.

The installation position, size, and number of pressure relief extinguishers 50 are appropriately set depending on the shape of the discharge flow rate fluctuation (or pressure change 1ll) of the pump. In addition, in the above repair example, the side plate 21 is a vane pump configured only on one side of the rotor 30, but in the case of a vane pump configured such that the rotor is sandwiched between a pair of side plates, the side plate 21 is attached to one or both side plates. It is also within the scope of the invention to provide a pressure relief system.

<Effects of the Invention> As described above, according to the present invention, the compression side pump chamber that communicates with the discharge port and the low pressure side pump chamber that communicates with the suction port are separated by the vane between the discharge port and the suction port by straddling the side surface of the vane. The structure has a pressure relief system that communicates with the bong chamber and forcibly relieves a portion of the pressure in the compression side bong chamber to the low pressure side pump chamber, so fluctuations in discharge pressure can be suppressed without using separate parts such as an accumulator. This makes it possible to suppress the fluctuation in the discharge flow rate to an extremely small extent. As a result, it has the effect of eliminating the vibrations and opening noises of the pump and piping caused by the discharge pressure fluctuations at a low cost.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal side view, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and FIG. 4 is an explanatory diagram of the operation of the main part of the present invention, FIG. 5 is a diagram showing the pressure pulsation with respect to the rotation angle, and FIG. 6 is a diagram showing the pressure pulsation with respect to the rotational speed of the pump. 1...First pump housing, 1C...Discharge port, 1f...Suction port, 1g...Discharge chamber, 2...
Second pump housing, 21... side plate, 2
5...Cam ring, 30...Rotor, 30b...
Compression side pump chamber, 30C...Low pressure side pump chamber, 40.
...Vane, 50...Compression relief groove.

Claims (1)

[Claims] The pump has a cam ring housed in a pump housing, a rotor that rotates inside the cam ring, and a plurality of vanes that slide in the radial direction within vane chambers provided radially on the rotor and that come into sliding contact with the cam surface of the cam ring. In a vane pump that increases or decreases the volume of each pump chamber divided between vanes as the rotor rotates, sucks liquid from a suction port and discharges it from a discharge port, the discharge is divided by the vanes between the discharge port and the suction port. A vane pump characterized in that a pressure relief groove is provided that communicates a compression side pump chamber communicating with a port and a low pressure side pump chamber communicating with a suction port by straddling the side surface of the vane.