JP2506638B2 - Pump device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is driven by a drive source whose rotational speed changes according to the operating state of an automobile engine or the like, and is applied to a fluid pressure actuator such as a power steering device at a predetermined flow rate. The present invention relates to a pump device that supplies a working fluid.

[Prior art]

In this type of pump device, for example, as shown in FIG. 4, the working fluid discharged from the pump 1 such as a vane pump to the pressure chamber 2 is controlled by the flow rate adjusting valve 3 to deliver a predetermined flow rate (not shown). ) To the power steering device, etc., and the excess flow rate passes through the suction passage 4 and suction ports 1a, 1b of the pump 1
I try to bypass it. A fluid supply passage 5 for introducing the working fluid from the reservoir to the pump 1 is opened to the suction passage 4, and the working fluid is sucked from the reservoir by utilizing the energy of the flow bypassing the suction passage 4.

[Problems to be solved by the invention]

In such a conventional technique, the jet flow 6 flowing into the suction passage 4 is influenced by the flow in the flow rate adjusting valve 3 and is inclined with respect to the axis of the suction passage 4 as shown in FIG.
Is eccentrically provided on the side where negative pressure is generated by this inclined jet flow 6, but since this negative pressure has a small range and a small value, it often causes insufficient suction of the working fluid from the reservoir. . Therefore, there is a problem that cavitation occurs in the pump 1 and erosion occurs in the rotor and vanes of the pump to reduce durability, or pulsation, vibration, noise and the like increase.

[Means for solving problems]

For this reason, the present invention controls the working fluid discharged from the pump whose rotational speed changes by a flow rate adjusting valve having a valve spool slidably fitted in the valve housing hole to control a predetermined flow rate. In a pump device configured to deliver excess working fluid to an intake passage while delivering it from an outlet, one end of the intake passage is communicated with the valve storage hole through a bypass hole opened and closed by the valve spool. A fluid supply passage for introducing a working fluid from a reservoir is opened in the suction passage, and the suction passage has a width larger than that of the bypass hole in a moving direction of the valve spool and with respect to an axial center of the bypass hole. It is characterized in that the fluid supply path is provided so as to be biased toward the opened side.

[Action]

The working fluid that is recirculated when the flow rate adjusting valve is opened becomes a jet flow passing through the bypass hole and flows into the suction passage. As a result, a negative pressure is generated in the suction passage located immediately after the bypass hole, but the suction passage has a larger width in the moving direction of the valve spool than the bypass hole and the fluid supply passage with respect to the center of the bypass hole in the width direction. Is located on the side where the fluid is opened, the region where negative pressure is generated is wider on the side where the fluid supply path is opened, and the value of the negative pressure that is generated is larger, so that the working fluid from the reservoir is Inhalation efficiency is improved.

〔The invention's effect〕

As described above, according to the present invention, the suction passage has a larger width in the moving direction of the valve spool than the bypass hole and is biased to the side where the fluid supply passage is opened with respect to the center of the bypass hole in the width direction. Since it is provided, a large negative pressure is generated in a wide area in the portion where the fluid supply passage in the suction passage is opened, so that the suction efficiency of the working fluid from the fluid supply passage to the suction passage is improved, resulting in insufficient suction. There is an effect that does not occur. Therefore, cavitation due to insufficient suction of the working fluid does not occur, and vibration due to this does not occur.
It will also reduce noise.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1 and FIG. 2, the pump 20 includes a cam ring 21, a rotor 22 having a plurality of vanes 23 slidably fitted therein in a radial direction,
The lid member 24, the side plate 25, and the pressing plate 26 are main constituent members. The rotor 22 has a rotating shaft 29 that is driven by an automobile engine whose rotation speed changes depending on operating conditions.
Is spline-coupled to the tip of the cam ring 21 and is rotationally driven, and causes a volume change in the pump chamber defined by the vane 23 between the elliptical cam surface 21a formed on the inner circumference of the cam ring 21 and the working fluid The suction is performed by the individual suction ports 20a, 21a and is discharged to the pressure chamber 27 from the two discharge ports 20b, 20b.

As shown in FIGS. 1 and 2, the housing of the pump 20
A cylindrical suction passage 11 is formed in the shaft 10 coaxially with the rotation shaft 29, and is communicated with the suction ports 20a, 20a via a communication groove 28 formed in the pressing plate 26. Further, as shown in FIG. 2, the housing 10 has a delivery path 16 communicating with the pressure chamber 27.
Further, a delivery port 17 is formed, and a throttle body 18 having a throttle hole 18a is press-fitted and fixed to the delivery passage 16. An eccentric and orthogonal fluid supply path 14 is opened near the tip of the suction path 11, the fluid supply path 14 is connected to a reservoir 13 containing a working fluid on the upper side of the housing 10, and a delivery port 17 is used for power steering. It is in communication with a device (not shown).

As shown in FIGS. 1 and 2, a flow rate adjusting valve 30 is provided between the pressure chamber 27 and the suction passage 11. Flow rate adjustment valve 30
Is slidable in the valve accommodating hole 31, the valve accommodating hole 31 formed in the housing 10 inclining with respect to the rotary shaft 29 of the pump 20, the stoppers 36 and 37 for sealing both ends thereof in a liquid-tight manner. A valve spool 3 which is fitted into the valve spool to separate the inside into first and second valve chambers 33 and 34
2 and a spring 35 which is provided in the second valve chamber 34 and biases the valve spool 32 toward the first valve chamber 33. The first valve chamber 33 has an introduction passage 15 formed in the housing 10.
As a result, regardless of the position of the valve spool 32, the valve chamber 32 is always communicated with the pressure chamber 27, while the second valve chamber 34 is communicated with the downstream side of the throttle hole 18a of the throttle body 18 via a passage (not shown). .

As shown in FIGS. 1 to 3, the housing 10 has a suction passage.
A bypass hole 12 having a diameter smaller than that of the suction passage 11 is formed so as to connect the tip end portion of the valve 11 and the valve storage hole 31. This bypass hole 12
Is formed parallel to the suction passage 11 and eccentric as will be described later. The end portion of the valve housing hole 31 side of the valve spool 32 is in contact with the stopper 36 by the spring 35 (two points in FIG. 1). It is closed in the state of the chain line) and is opened in the state where the valve spool 32 moves against the spring 35 (the state of the solid line in FIG. 1) and opens in the inner peripheral surface of the valve housing hole 31. ing. As shown in FIG. 1, the bypass hole 12 has a central shaft 01 and a valve spool 32 for opening the bypass hole 12.
The suction passage 11 is formed so as to be inclined such that the angle α with the moving direction X of the pump is an acute angle, and is formed coaxially with the rotating shaft 29 of the pump 20 as described above. It is arranged so as to be eccentric on the side where the passage 14 is opened.
This eccentricity should be smaller than the radius of the bypass hole 12,
The central axis 02 of 11 is located in the bypass hole 12.

As described above, since the bypass hole 12 has a smaller diameter than the suction passage 11, the suction passage 11 has a width larger than that of the bypass hole 12 in the moving direction of the valve spool 32. Is biased to the side where the fluid supply passage 14 is opened with respect to the center of the bypass hole 12 in the width direction.

In the above configuration, the rotor for the automobile engine
When 22 is rotationally driven, the working fluid is sucked from the suction passage 11 into the pump 20 via the suction ports 20a, 20a, pressurized and discharged into the pressure chamber 27 via the discharge ports 20b, 20b. The working fluid discharged into the pressure chamber 27 is the throttle hole 18a, the inside of the throttle body 18,
It is supplied to the power steering apparatus via the delivery path 16 and the delivery port 17 to operate it. The used working fluid is returned to the reservoir 13 through the discharge passage.

Since the discharge flow rate is small while the rotation speed of the pump 20 is low, the valve spool 32 closes the bypass hole 12 and the entire discharge flow rate from the pump 20 is sent out from the outlet 17, but the rotation speed increases and discharge As the flow rate increases, the valve spool 32 slides against the spring 35 to open the bypass hole 12 so that the pressure difference before and after the throttle hole 18a becomes substantially constant, and the predetermined flow rate passes through the throttle hole 18a. Is discharged from the outlet 17, and the excess flow rate is passed from the bypass hole 12 through the suction passage 11 to the suction port 20.
It will be returned to a, 20a.

As shown in FIG. 1, the working fluid recirculated into the suction passage 11 flows into the jet flow J passing through the bypass hole 12. Since the bypass hole 12 has a smaller diameter than that of the suction passage 11, this jet J causes a negative pressure in the suction passage 11 located immediately after leaving the bypass hole 12, but the suction passage 11 causes fluid to the bypass hole 12. Since it is eccentric to the side where the supply passage 14 is opened, the region in the suction passage 11 where the negative pressure is generated is wider on the side where the fluid supply passage 14 is opened and the value of the generated negative pressure is also larger. Therefore, this large negative pressure acts on the opening of the fluid supply passage 14 to the suction passage 11 over a wide range, so that the suction effect of the working fluid from the reservoir sucked from the fluid supply passage 14 to the suction passage 11 is improved,
No shortage of inhalation will occur.

[Brief description of drawings]

1 to 3 show an embodiment of a pump device according to the present invention. FIG. 1 is a horizontal sectional view along the longitudinal direction, FIG. 2 is a vertical sectional view thereof, and FIG. 3 is a sectional view of FIG. lll-III cross section,
FIG. 4 is a partial sectional view of the prior art. Explanation of symbols 11 …… Intake passage, 12 …… Bypass hole, 14 …… Fluid supply passage,
17 …… Sending port, 20 …… Pump, 20a …… Suction port, 30
...... Flow control valve, 31 …… Valve storage hole, 32 …… Valve spool,
X: Direction of movement.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-56-47694 (JP, A) JP-A-58-167892 (JP, A) JP-A-52-132403 (JP, A) Actual development Sho-59- 131989 (JP, U) Actual Open Sho 58-40587 (JP, U) Actual Open Sho 59-43690 (JP, U) Special Public Official Sho-45-9110 (JP, B1)

Claims (1)

(57) [Claims] 1. A working fluid discharged from a pump whose rotational speed changes is controlled by a flow rate adjusting valve having a valve spool slidably fitted in a valve housing hole to deliver a predetermined flow rate. In the pump device configured to bypass the excess working fluid to the suction passage, the suction passage has one end communicated with the valve storage hole via a bypass hole opened and closed by the valve spool. A fluid supply passage for introducing a working fluid from a reservoir is opened in the suction passage, the suction passage has a width larger than that of the bypass hole in the moving direction of the valve spool, and the fluid is provided with respect to the axial center of the bypass hole. A pump device, wherein the pump device is provided so as to be biased to the side where the supply passage is opened.