JPS5963387A - Variable capacity type pump - Google Patents

Abstract

PURPOSE:To reduce the eccentricity of a cam ring and discharge flow for reducing power loss in on-load running of a pump by attenuating a press force of a spring against the cam ring in the no-load running. CONSTITUTION:In the no-load running of a pump, a second spool 49 is held at a position to close a communicating path 47 and a first spool 42 held at a position where a communicating path 44 communicates to a drain port 45 so that a spring carrier 37 is slided against a balancing spring 39 by the internal pressure of the pump. Thus, the force of a ring pressing spring 38 interposed between the cam ring 14 and the spring carrier 37 is reduced so that the eccentricity of the cam ring 14 is reduced to reduce discharge flow.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a variable displacement pump suitable for a power steering device.

<Prior Art> Generally, a pump used in a power steering device is driven by an engine regardless of whether or not the power steering device is in operation. Considering the driving conditions of automobiles, most of the time the steering wheel is not operated, and the pump is operated without load. Therefore, in order to improve the fuel efficiency of automobiles,
The first important point is how to keep the power loss low during no-load operation of the pump.

<Objective of the Invention> An object of the present invention is to reduce the amount of eccentricity of the cam ring by weakening the pressing force against the cam ring by the spring during no-load operation in a variable displacement pump configured to discharge a required flow rate under load. The aim is to reduce the discharge flow rate and thereby reduce power loss during no-load operation of the pump.

<Example> Embodiments of the present invention will be described below based on the drawings.

1 and 2, 10 indicates a pump housing, and each pump housing 10 includes a front housing 11, a guide housing 12, and a rear housing 1.
3.

A cam ring 1 is inserted into the inner hole 12a of the guide housing 12.
4 is housed so as to be movable in the
is formed. A rotor 17 that holds a number of vanes 16 so as to be slidable in the direction of radial force is rotatably housed in the cam ring 14 , and this rotor 17 has a spline attached to one end of a rotating shaft 18 that is rotatably supported on the front housing 11 . engaged.

A suction boat 21 communicating with the suction area of the pump chamber and a discharge boat 22 communicating with the discharge area of the pump chamber are formed on the inner surface of the housing 11 of the fluorocarbon 1. The suction boat 21 has a suction port 23 provided in the front housing 11.
The discharge bows 1 to 22 are connected to the pressure fluid passage I5.
is communicated with.

Elongated holes 11a and 19a are formed in the inner surfaces of the front housing 11 and the pressure brake 1-19, which face each other with the cam ring 14 in between.
Both ends of a seal pin 27 extending in the axial direction are fitted into the axially extending seal pin 27 . This seal pin 27 is attached to the guide housing 12.
It is in close contact liquid-tightly with the two-part peripheral wall of the header 12a. Further, a fitting groove 14a into which the seal pin 27 can be fitted is formed in an axial direction at a portion of the outer periphery of the cam ring 14 that faces the seal pin 27. This cam ring 14
is pushed upward by the fluid pressure in the pump chamber to tightly fit the fitting groove 14'a into the seal pin 27. As a result, the seal pin 27 supports the force J ring 14 so as to be able to swing in the left-right direction in FIG. It seals the space between them. M) A fitting recess 12b extending in the axial direction is formed in the lower peripheral wall of the inner hole 12a of the guide housing 12, and a gap gate 28 is disposed in this fitting recess 12b. An orifice 29 is formed between the gap adjustment portion 4428 and the outer circumferential surface of the cam ring 14, and the orifice 29 and the seal pin 27 cause a first pressure action to pass the pressure fluid 1Jrl (/315) to the discharge boat 22. Chamber 15Δ and discharge port 3
It is divided into a second river force action chamber 1513 leading to 0,
A supply port of the power steering device is connected to this discharge I'30.

The guide housing 12 includes the second pressure action chamber 1.
A hole 35 that opens L1 at 5I3 is formed in the radial direction of the cam ring 14, and one end of this hole 35 is connected to the guide housing 12.
It is closed by a pro-tsuku 36 fixed to the. A spring receiver 37 is movably fitted into the hole 35,
A ring pusher spring 38 is inserted between one end of the spring receiver GJ37 and the outer peripheral surface of the cam ring 14, and a balance spring 39 is inserted between the spring receiver Reno 37, α111, and the L1 hook 36. is inserted.The repulsive force of the spring 38 for pushing down the ring holds the cam ring 14 in the left direction in FIG. , the spring receiver 37 is connected to both springs 38.3
9 is held in a balanced position.

The cock 1 cock 3 into which the balance spring 39 is inserted
A valve hole 41 is communicated with a chamber 40 formed between the spring receiver 6 and the spring receiver 37, and the first spool 4 is connected to the valve hole 41 of the valve hole 41.
2 is slidably inserted by a predetermined amount. 1st spool 4
2 is held at a position υ1; 11 above the spacer 3121 by the repulsive force of the spring 43, and in this state, the chamber 40 is connected to the rigid body 1 through the communication path 44 provided in the first spool 42. However, due to the pressure inside the chamber 4, the first spool 4
2 is slid a predetermined distance r1 against the spring 43, communication between the chamber 40 and the discharge 1145 is interrupted. Also, the room 40 and JJI' Ill D
A relief valve 46 is inserted between the chamber 45 and the chamber 45, and when the pressure inside the chamber 40 reaches a preset relief pressure, the chamber 40
The pressure inside will be vented and released to I45.

Further, a valve hole 48 is formed in the communication passage 47 that communicates the chamber 40 and the second pressure action chamber 15B.
A second spool 49 is slidably inserted into 8, and is held by the repulsive force of the spring 50 at the human force 1'+gl in FIG. 2 which normally closes the communication 1/847. Such second
The spool 49 does not respond to the pump internal pressure that occurs during no-load operation of the pump, but responds to the rise in pump internal pressure that occurs when the handle is operated, and resists the spring 50 for a predetermined amount of time.
The 3 m passage 47 is opened to a certain aperture area.

Next, I will explain Ruri's first work based on the structure described in -1-.

When the pump is operated without load, the internal pressure of the pump is low (jf4), the second spool 49 is held in the position that closes the series IIR circuit 47, and the first spool 4
2 is held in a position where the communication passage 44 communicates with the discharge 1-145, and the chamber 40 is opened to the reservoir side. Therefore, the spring support 37 is slid against the balance spring 39 due to the pump internal pressure, and is thereby inserted between the cam ring 14 and the spring support 37, reducing the repulsive force of the spring 38 for pushing down the ring. Therefore, cam ring 14
The amount of eccentricity is reduced, and the discharge flow rate is reduced. (41st
(m dashed line) When the internal pressure of the pump increases by 111% due to the operation of the control valve of the power steering device in conjunction with the steering wheel operation, the pressure causes the second
The spool 49 is moved against the spring 5o, the communication passage 47 is opened to a certain degree of throttle opening, and the chamber 4o is communicated with the second pressure application chamber 15B via the communication passage 47. Therefore, the first spool 42 is moved by li+1 against the spring 43 due to the pressure inside the chamber 4o, and the communication between the communication path 44 and JJI' 1-111-145 is cut off. As a result, the pressure inside the chamber 40 is maintained at the same pressure as the pressure inside the second pressure acting chamber 15. Cam ring 14 by push-down spring 38
The pushing force is increased, the force J-ring 14 is displaced in a direction that increases the amount of eccentricity, and the discharge flow rate is increased to a predetermined amount necessary for the power steering device. (Solid line in Figure 2) When the internal pressure of the pump reaches a predetermined relief pressure due to an increase in load, the relief valve 46 is activated and the pressure fluid in the second pressure application chamber 1513 is transferred to the reservoir side via the chamber 40 and the relief valve 46. leaks to.

At this time, a pressure difference is created before and after the communication path 47 due to the throttle effect of the communication path 47, and a difference occurs in the fluid pressure acting on both ends of the spring receiver 37. Therefore, the spring catcher]
37 is slid against the repulsive force of the balance spring 39, and the pushing force on the cam ring 14 by the spring 38 for the ring pusher 1 is reduced, so that the amount of eccentricity of the cam ring 14 with respect to the rotor 17 is reduced, and the pump The discharge flow rate is reduced, and a pressure increase exceeding the relief pressure is suppressed.

<Effects of the Invention> As described above, the present invention reduces the pushing force of the cam ring by the spring to reduce the discharge flow rate during no-load operation of the pump, and increases the required discharge flow rate by increasing the load pressure. Since the pump is designed to increase flow rate, the pump drive horsepower that is lost during no-load operation can be significantly reduced, contributing to improved fuel efficiency of automobiles.

Moreover, according to the present invention, even when the load pressure reaches the relief pressure, the force exerted by the spring on the cam ring can be reduced to reduce the discharge flow rate, which has the effect of reducing the energy lost during relief. 01-1! Tekanade-U
and others! climb.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a sectional view of a variable displacement pump, FIG. 2 is a sectional view taken along the line Rho-II in FIG. -n1 line arrow sectional view, 4th
The figure is a diagram showing the discharge flow rate versus the pump rotation speed. 10...Pump housing, 14...Cam ring,
15A...First pressure action chamber, 15B...Second pressure action chamber, 16...Höhn, 17...Rotor, 21...
・Suction boat, 22... Discharge boat, 29... Orifice, 35... Hole, 37... Spring receiver, 3
8... Spring for ring pressing, 39... Spring for balance, 40... Chamber, 42... First spool, 46... Relief valve, 49... Second spool. Patent applicant Yutaka IJ, l Koki Co., Ltd. Figure 2 '+1') jl

Claims (1)

[Claims] (1) A cam ring is housed in a pump housing so as to be movable in the radial direction, a rotor holding a plurality of vanes is rotatably housed inside the cam ring, and the rotor is connected to a discharge boat of the pump. An orifice is provided in the discharge passage, the upstream and downstream sides of the orifice are communicated with first and second pressure chambers facing both sides of the cam ring, and the pump housing is open to the second pressure chamber. A spring receiver is slidably fitted into this hole, and a ring pusher (=J spring is inserted between one end of the spring receiver and the cam ring, and the spring receiver is inserted into the spring receiver). A balance spring is inserted between the end and the pump housing side, and a first spool is provided that communicates the chamber in which the balance spring is inserted with the reservoir side when the pump is not loaded and cuts off the communication when the pump is loaded. Further, a second spool is provided that communicates the chamber with the second pressure acting chamber via a throttle when the pump is under load and blocks the communication when there is no load, and communicates the chamber with the reservoir side via a relief valve. (2) The variable displacement pump according to claim 1, wherein the first and second spools are configured to respond to changes in the internal pressure of the pump.