JPS63637B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pump device for a power steering device, and its purpose is to increase the pump suction efficiency by utilizing the kinetic energy of fluid discharged from the pump. The goal is to maximize the velocity energy of the flow and supercharge it to the pump suction side, thereby further increasing the pump suction efficiency.

In conventional pump devices, surplus flow discharged from the pump in order to supply the power steering device with fluid whose flow rate is adjusted to a constant flow rate by the flow rate adjustment valve is bypassed from the flow rate adjustment valve to the pump suction port via the bypass passage. In order to increase pump suction efficiency by utilizing the kinetic energy of this bypass flow, a fluid supply path is provided midway through the bypass passage to guide the fluid in the fluid tank, and the fluid is supercharged into the pump suction passage. There is.

However, in the conventional device described above,
The confluence point of the bypass flow and the make-up flow is located downstream of the bypass passage opening whose opening is adjusted by the flow rate adjustment spool valve, and the velocity energy of the bypass flow is not fully utilized. In other words, the area of the bypass passage where the fluid supply passage is opened is significantly larger than the area of the opening of the bypass passage whose opening is adjusted by the spool valve, so the bypass flow that is bypassed from the pump discharge passage to the bypass passage is Although the fluid flows out at a high speed at the bypass passage opening limited by the control edge of the spool valve, the flow velocity is considerably reduced at the portion where the fluid supply passage is opened.

Therefore, in order to further improve the pump suction efficiency, the present invention aims to bring the confluence point of the bypass flow and the make-up flow as close as possible to the bypass passage opening whose opening is adjusted by the flow rate adjustment spool valve. This is characterized in that the fluid supply path opens into a valve storage hole into which a spool valve is fitted.

Embodiments of the present invention will be described below based on the drawings. In FIG. 1, reference numeral 10 denotes a pump housing, and a hollow chamber 11 with a bottom is formed in this pump housing 10, and this hollow chamber 11 is open at one end surface of the pump housing 10. This hollow chamber 1
A through hole 13 is provided in the lid member 12 that closes the opening of 1.
A rotary shaft 14 is inserted through the through hole 13 and rotatably supported by bearings 15a and 15b. The hollow chamber 11 includes a cam ring 16 that is in contact with one end surface of the lid member 12, and a side plate 17 that is in contact with the other side of the cam ring 16.
A pressing plate 18 that is in contact with the other side of the side plate 17 is housed, and this pressing plate 18
A spring 1 is installed between the pump housing 10 and the pump housing 10.
9 is compressed and inserted. A cam surface 20 is formed on the inner circumference of the cam ring 16, and this cam surface 20
A rotor 22 that radially slidably holds a plurality of vanes 21 whose outer ends are in sliding contact with the cam ring 1
It is housed in 6. The rotor 22 is splined to one end of the rotating shaft 14.
The left side surface of the rotor 22 and the left end surface of the vane 21 are in sliding contact with the end surface of the lid member 12, and the right side surface of the rotor 22 and the right end surface of the vane 21 are in sliding contact with the side surface of the side plate 17, and each sliding surface has a sealing effect. will be done.
As a result, a plurality of pump chambers partitioned by the vanes 21 are formed between the cam surface 20 of the cam ring 16 and the rotor 22, and the volume of each pump chamber changes as the rotor 22 rotates. Suction ports 25 and 26 are formed in the lid member 12 and the side plate 17 corresponding to the pump chamber that is in the expansion stroke, and suction ports 25 and 26 are formed in the lid member 1 to correspond to the pump chamber that is in the compression stroke.
2 and the side plate 17 have discharge grooves 27, 28.
is formed.

A suction port 25 formed in the lid member 12 and a suction port 26 formed in the side plate 17 are communicated with each other through a passage 29 formed between the cam ring 16 and the pump housing 10. Furthermore, on the side plate 17 side, this suction port 26 is communicated with a passage groove 30 cut in the press plate 18, and communicates with a central through hole 18a of the press plate 18. Side plate 17
The discharge groove 28 formed in the pressure plate 18 communicates with the pressure chamber 35 through the through hole 32 of the pressure plate 18 .

The pump housing 10 has a valve housing hole 36 orthogonal to the axis of the rotating shaft 14, as shown in FIG.
and a pressure chamber 3 with one end opened in this valve storage hole 36.
5, an introduction passage 37 whose other end is open, a bypass passage 38 whose one end is opened to the center through hole 18a of the pressing plate 18, and the other end to the valve housing hole 36; A fluid supply path 39 has one end opened to the valve storage hole 36 and the other end opened to the fluid tank 50, and a delivery path 40 has one end opened to the pressure chamber 35 and the other end opened to the outside of the pump housing 10. It is set up. Valve storage hole 36
A spool valve 43 is slidably inserted into the spool valve 43 in order to close the communication passage between the introduction passage 37 and the bypass passage 38 and to adjust the opening degree of the communication passage. Valve chamber 41 and second valve chamber 4
2 is formed. A spring 44 that presses the spool valve 43 is provided in the second valve chamber 42, and normally blocks communication between the first valve chamber 41 and the bypass passage 38. The delivery path 40 is provided with a constriction section 45, and the fluid that has passed through the constriction section 45 is guided to the second valve chamber 42 through an unillustrated passage.
Fluid that does not pass through the throttle portion 45, that is, fluid discharged into the pressure chamber 35, is guided to the first valve chamber 41 through the introduction passage 37. As a result, the pressure before passing through the constriction part 45 and the pressure after passing through the constriction part 45 act on both end surfaces of the spool valve 43, so that the spool valve 43 is moved in the axial direction in accordance with the pressure drop in the constriction part 45. The degree of opening of the bypass passage 38 is adjusted to maintain the pressure drop at 45 at a constant value. Therefore, the flow rate passing through the constriction portion 45 is approximately constant, and the flow rate through the outlet port 4 is approximately constant.
9 to the power steering device. The surplus flow discharged by the pump is transferred from the first valve chamber 41 to the bypass passage 38.
The pump is bypassed and returned to the pump suction ports 25 and 26. Since a fluid supply path 39 is opened in the valve storage hole 36 close to the opening of the bypass passage 38, the insufficient fluid is drawn in from the fluid tank 50 according to the flow velocity of the bypass flow to perform supercharging.

When the pump is driven, the fluid in the fluid tank 50 flows through the fluid supply path 39, the bypass path 38, and the pressure plate 1.
It is sucked into the pump chamber through the suction ports 25 and 26 through the passage grooves 30 of No. 8, and is discharged into the pressure chamber 35 through the discharge groove 27 of the side plate 17 and the through hole 32 of the press plate 18. The fluid discharged into the pressure chamber 35 passes through the constriction part 45 and is sent to the power steering device from the outlet 49, and the fluid returned from the power steering device is guided to the fluid supply path 39 and sucked into the pump again. be done.

If the pump rotation speed is low, the pump discharge flow rate is also small, so the spool valve 43 closes the valve passage, and the entire amount is sent from the throttle section 45 to the power steering device.
As the rotational speed increases, the discharge flow rate also increases, opening the valve passage and bypassing the excess flow to the bypass passage 38. Due to the bypass flow, the fluid in the fluid tank 50 is drawn in at the connection point between the fluid supply path 39 and the bypass path 38, and is supercharged to increase the pump suction pressure.

At this time, the fluid supply path 39 leading to the fluid tank 50 is connected to the valve storage hole 3 into which the flow rate adjustment spool valve 43 is fitted.
6, and the confluence point of the bypass flow and make-up flow is brought close to the bypass passage opening where the flow velocity of the bypass flow is highest, so that the velocity energy of the bypass flow is utilized to the maximum, and the suction port 25 , 26 can be further improved.

As described above, according to the present invention, since the fluid supply path leading to the fluid tank is opened in the valve storage hole in which the flow rate adjustment spool valve is fitted in the vicinity of the bypass passage, the bypass flow The make-up flow and the make-up flow meet at the bypass passage opening whose opening is adjusted by the spool valve, and this makes it possible to make maximum use of the velocity energy of the bypass flow, resulting in improved suction efficiency compared to conventional systems. You will be able to improve your skills. Therefore, even when the pump rotates at high speed, cavitation can be reliably prevented and the generation of noise can be effectively eliminated.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a pump device showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line -- in FIG. 10...Pump housing, 16...Cam ring,
17...Side plate, 18...Press plate, 2
1...Vane, 22...Rotor, 25, 26...Suction port, 28...Discharge groove, 35...Pressure chamber, 36...Valve storage hole, 37...Introduction passage, 38...Bypass passage, 3
9...Fluid supply path, 43...Flow rate adjustment spool, 4
5... Throttle part, 49... Delivery port, 50... Fluid tank.

Claims (1)

[Claims] 1. In a pump device in which pressurized fluid discharged from a pump is adjusted to a substantially constant flow rate by a flow rate regulating valve and supplied to a power steering device, and surplus flow is bypassed to a pump suction port, A bypass passage for bypassing surplus flow to the pump suction port is opened to a valve storage hole in which a spool valve of the flow rate adjustment valve is fitted, and a fluid supply path leading to a fluid tank is connected to the valve storage hole to the opening of the bypass passage. A pump device characterized in that the openings are adjacent to each other.