JPH063191B2 - Vane pump - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vane pump used for, for example, power steering.

(Prior Art) As shown in FIGS. 1 to 7, a conventional vane pump for power steering has a cam ring 1 having a substantially elliptical inner surface 1a. In this structure, the rotor 3 is arranged, the thrust plate 9 and the pressure plate 13 are arranged so as to sandwich the cam ring 1 and the rotor 3, and the rotor 3 is mounted inside the housing. An inflow oil passage 6 formed inside the housing, a low pressure chamber 7 formed between a circumferential groove formed in the inner wall portion of the housing 5 and the outer peripheral portion of the cam ring 1, the cam ring 1 of each of the thrust plate 9 and the pressure plate 13, Through the intake ports 8 formed on the contact surface side of the cam ring 1 into the large-diameter side internal space of the cam ring 1, and the rotation of the rotor 3 The ink is discharged from the discharge ports 10, 10 formed in the charger plate 13. The discharged oil is supplied to the power steering from the supply port 12 through the flow control valve 14 from the high pressure chamber 11 formed on the back surface of the pressure plate, and a part of the oil is supplied from the return port 15 to the inflow oil passage 6
It is supposed to be returned to.

The recesses 16 and 16 formed on the contact surface side of the thrust plate 9 with the cam ring 1 allow the oil discharged from the inner space on the large diameter side of the cam ring 1 to the recesses 16 and 16 to the small diameter side of the ring portion of the cam ring 1. This is for joining the discharge ports 10, 10 of the pressure plate 13 through the through hole 1b formed at the position.

Further, the through holes 18, 18 formed in the plates 9, 13 and the cam ring 1 respectively connect the plates 9, 13 and the cam ring 1 integrally by inserting a pin into the holes 18, 18. And also pin 19
Fixes the plates 9 and 13 and the cam ring 1, which are integrally connected, to the housing 5. Reference numeral 17 is a blind plug for closing the opening after the inflow oil passage 6 is bored from the outside of the housing.

However, in the conventional pump structure as described above, since the suction tube 4 and the inflow oil passage 6 and the inflow oil passage 6 and the low pressure chamber 7 are orthogonal to each other, the suction tube 4 and the return port 15 flow into the low pressure chamber 7. There is a drawback that the resistance of the oil flow to be increased becomes large and the oil flow is disturbed to cause pulsation and noise. Further, since the inflow oil passage 6 has to be bored from the outside of the housing, A surplus portion is required to take a machining allowance for the oil passage 6, which has been an obstacle to reducing the size and weight of the pump. Further, after the oil passage 6 is bored, it is necessary to close the opening of the oil passage with the blind plug 17, which has a disadvantage of increasing the number of parts.

(Object) The present invention aims to eliminate the above-mentioned conventional drawbacks.

(Example) Next, an example of the present invention shown in FIG. 8 will be described. The same parts as those of the structure of the pump described in the related art are designated by the same reference numerals.

The linear inflow oil passage 21 that connects the suction tube 4 and the low pressure chamber 7 formed in the inner wall portion of the housing 20 is formed at an obtuse angle with respect to the axis of the suction tube. The obtuse angle is preferably between 100 ° and 150 °. The inflow oil passage 21 communicates with the low pressure chamber 7 so as to be orthogonal to the axis of the cam ring 1 and to be orthogonal to the axis of a hole 22 for mounting a flow control valve, which is provided so as to be orthogonal to the axis. The reflux port 15 of the valve is formed at the same time and processed inside the casing.

(Effect) According to the present invention, the inflow oil passage 21 that communicates the suction tube 4 and the low pressure chamber 7 is formed into a straight passage that forms an obtuse angle with respect to the axis of the suction tube and is processed inside the casing. The flow of oil from the tube into the low pressure chamber becomes smooth, and the passage resistance in the oil passage is reduced. Therefore, it is possible to prevent pulsation and noise from occurring. Moreover, since it is not necessary to process the inflow oil passage 21 from the outside of the housing, it is not necessary to form a surplus portion for providing the inflow oil passage in the housing itself, and the pump itself can be made smaller and lighter. Further, since the oil passage 21 is bored from the low pressure chamber, no blind plug is required and the number of parts can be reduced.

It is advantageous that the angle formed by the inflow oil passage 21 and the axis of the suction tube is as close to 180 ° as possible in order to smooth the oil flow, but if the angle is too large, the inflow oil passage itself becomes long. However, there is a disadvantage that the housing becomes large by that much, and in order to satisfy both the oil flow and the size and weight reduction of the pump, the angle is 100 ° to
The optimum angle is 150 °, especially around 120 °.

[Brief description of drawings]

1 is a side sectional view of a conventional vane pump for power steering, FIG. 2 is a sectional view taken along the line BB of FIG. 1, FIG. 3 is a sectional view taken along the line AA of FIG. 1, and FIG. 1 is a front view of the thrust plate of FIG. 1, FIG. 5 is a front view of the cam ring, FIG. 6 is a front view of the rotor, FIG. 7 is a front view of the pressure plate, and FIG. 8 is a side sectional view of an embodiment of the present invention. is there. 4 ... Suction tube 7 ... Low pressure chamber 15 ... Flow control valve return port 20 ... Housing 21 ... Inflow oil passage 22 ... Flow control valve mounting hole

Claims (1)

[Claims] 1. A housing provided with a suction tube, a cam ring disposed inside the housing, a rotor mounted inside the cam ring and having a plurality of vanes on the outer circumference, and the rotor and the cam ring sandwiched from both sides. And a pressure plate having a pair of suction ports, and a flow control valve provided so that the axis of the cam ring is offset so as to be orthogonal to the axis of the cam ring. In the vane pump in which the low-pressure chamber is formed inside the housing and the low-pressure chamber is closed by a portion that passes through the pair of suction ports, the inflow oil passage extending from the suction tube to the low-pressure chamber is orthogonal to the axis of the flow control valve mounting hole. As well as communicating with the mounting hole,
The downstream side of the suction tube of the inflow oil passage communicates with the suction tube so as to form an obtuse angle with respect to the axis of the suction tube to form a straight passage extending substantially in the axial direction of the cam ring, which is processed inside the casing. And the vane pump.