JPH073035Y2 - Liquid pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a liquid pump used as a drive source for a vehicle power steering device or the like.

<< Prior Art >> A conventional liquid pump of this type is disclosed in, for example, Japanese Patent Laid-Open No.
The one described in JP-A-218478 is known.

The outline of this pump is shown in FIG. A flow rate control valve device 2 is provided in a discharge hole 1 extending from a pump unit (not shown). This flow control valve device 2
Is a throttle 4 that controls the pressure fluid flowing from the discharge hole 1 of the pump portion to the delivery port 3 and a pressure difference across the throttle 4 that slides to open and close the bypass hole 5 to control the flow rate to the delivery port 3. It comprises a control spool 6 for controlling, and a solenoid valve 7 mounted coaxially with the control spool 6 for adjusting the opening of the throttle 4. The electromagnetic valve 7 includes an electromagnetic solenoid 9, a movable spool 10 that is displaced by energization of the electromagnetic solenoid 9, and a valve shaft 11 that is integrally coupled to the movable spool 10. Movable spool 10
Is normally pressed by the spring 13 together with the valve shaft 11 to the left in the figure to fully open the throttle 4. As a result, the fluid flowing out from the throttle 4 flows into the delivery port 3 through the inflow opening 3a into the delivery port 3. Further, on the downstream side of the throttle 4, an inflow opening 15a of a pressure-sensitive orifice 15 communicating with the control spool 6 is formed on the side facing the inflow opening 3a, and the pressure on the downstream side of the throttle 4 is from this inflow opening 15a. It is transmitted to one side of the control spool 6. The other side of the control spool 6 faces the upstream side of the throttle 4, the control spool 6 moves according to the pressure difference between the upstream side and the downstream side of the throttle 4, and part of the fluid from the discharge hole 1 is bypassed. Reflux to 5.

<Problems to be Solved by the Invention> However, in the flow control valve device 2 having the above structure, the fluid flowing out from the throttle 4 directly flows into the pressure-sensitive orifice 15 at the inflow opening.
There is a problem that the dynamic pressure is transmitted to 15a and is directly transmitted to one side of the control spool 6, and the operating characteristics of the flow control valve device 2 vary.

Further, as shown in FIG. 9, a throttle 4 and a discharge hole which is opened to both sides from the throttle 4 are provided at the tip of the valve shaft 11 of the solenoid valve 7.
There is also one in which 17 is integrally formed. In this case, the solenoid valve 7
When the screws are screwed together, the direction of the discharge hole 17 is different for each solenoid valve 7, and the outflow hole 17 becomes the inflow opening 15a of the pressure sensitive orifice 15.
If the flow rate of the fluid flowing out from the outflow hole 17 is directly transmitted to the pressure sensitive orifice 15, and if the outflow hole 17 does not match the inflow opening 15a of the pressure sensitive orifice 15, the fluid flowing out of the outflow hole 16 Therefore, there is a problem that the static pressure is transmitted to the pressure sensitive orifice 15 and the operating characteristics of the flow control valve device 2 vary depending on the mounting state of the solenoid valve 7.

The present invention has been made in view of the above problems, and provides a liquid pump that can suppress the direct transmission of dynamic pressure to a pressure-sensitive orifice and reliably prevent variations in operating characteristics of a control device. The purpose is to

<Means for Solving the Problems> In order to achieve the above-mentioned object, the present invention provides a flow rate adjusting valve that is interposed in a discharge passage of a liquid pump and adjusts the amount of fluid flowing to the downstream side, and a flow rate adjusting valve of the flow rate adjusting valve. A flow rate control device that recirculates a part of the fluid on the discharge side to the suction side in accordance with the pressure difference between the upstream side and the downstream side, wherein the flow rate adjusting valve is a throttle section formed at the discharge passage upstream side opening; The present invention is characterized in that a buffer portion is provided so that the fluid discharged from the throttle portion does not directly flow into the pressure sensitive orifice of the flow rate control device and its dynamic pressure is not transmitted to the flow rate control device.

<< Operation >> In the liquid pump having the above structure, the dynamic pressure of the fluid flowing downstream of the flow rate adjusting valve is reliably buffered by the buffer section and is transmitted to the pressure-sensitive orifice of the flow rate control device, so that the variation in the operating characteristics of the flow rate control device is prevented. It can be surely prevented.

<< Embodiment >> An embodiment of the present invention will be described below with reference to the accompanying drawings.

The overall structure of the liquid pump of the present invention is as shown in FIGS. Reference numeral 21 in the figure indicates a housing of the liquid pump.
22 is installed. The pump unit 22 is composed of a suction chamber, a compression unit including a rotor equipped with a cam ring and a vane, and a discharge chamber, which are not shown. The discharge chamber communicates with the discharge port 24 via the discharge passage 23, and the valve chamber 25 is formed in the discharge passage 23. A flow rate adjusting valve 26 for adjusting the amount of fluid flowing through the discharge passage 23 is formed in the valve chamber 25. In addition, the valve chamber 25
A flow rate control device 29 is connected to the device via a pressure sensitive orifice 28. The flow rate control device 29 is configured to recirculate a part of the fluid on the discharge chamber side to the suction chamber side according to the pressure difference between the suction chamber and the discharge chamber of the pump unit 22.

The flow rate adjusting valve 26 includes a discharge passage 23 in the valve chamber 25 and an upstream opening 31.
A throttle portion 32 formed in the outlet passage 23 to reduce the flow passage cross-sectional area of the discharge passage 23,
The valve body 33 is arranged so as to face the throttle portion 32 and adjusts the opening degree of the throttle portion 32. The flow rate adjusting valve 26 is formed integrally with an electromagnetic control device 35 that controls the opening / closing of the adjusting valve 26 by a vehicle speed signal or the like.

As shown in FIG. 2, when the electromagnetic control device 35 is used as a pump for power steering, for example, a steering sensor for detecting a steering angle and a steering speed of a steering wheel, a vehicle speed sensor, a rotation speed sensor of an engine, etc. An electromagnetic solenoid 37 whose energized state is controlled by a signal, and a movable spool 38 which is displaced by energizing the electromagnetic solenoid 37
And a valve rod 39 integrally connected to the movable spool 38 and having a valve element 33 at its tip.

As shown in FIG. 1, discharge ports 41 and 42 that are open to both sides are formed on the downstream side of the throttle portion 32. The discharge ports 41 and 42 have a buffering portion that prevents the fluid discharged from the discharge ports 41 and 42 into the valve chamber 25 from directly flowing into the pressure sensitive orifice 28 and transmitting the dynamic pressure thereof to the flow rate control device 29. As the discharge port 41,4
A tapered (trumpet-shaped) chamfer 43 whose diameter is gradually increased toward the outside is provided.

In the liquid pump configured as described above, when this pump is operated, the pump portion 22 operates to pressurize the fluid in the suction chamber at the compression portion and discharge the fluid into the discharge chamber, through the discharge passage 23. It is sent from the discharge port 24 to an external device such as a servo valve.

At this time, the fluid passes through the valve chamber 25 in the discharge passage 23, and the flow rate of the fluid is controlled in the valve chamber 25 by the signals from the steering sensor, the vehicle speed sensor, the rotation speed sensor, and the like. Specifically, the energization state of the electromagnetic solenoid 37 of the electromagnetic control device 35 is adjusted by a control signal sent from a control unit (not shown) in response to signals from the steering sensor, the vehicle speed sensor, the rotation speed sensor, etc. The movable spool 38 is displaced accordingly.
The valve element 33 at the tip of the valve rod 39 integrally connected to the movable spool 38 adjusts the flow passage cross-sectional area of the throttle portion 32. At this time, the fluid is discharged into the valve chamber 25 from the discharge ports 41, 42 on the downstream side of the throttle portion 32, but this fluid is generated by the tapered (trumpet-shaped) chamfer 43 of the discharge ports 41, 42. The discharge flow velocity is greatly reduced, and it is diffused in all directions. As a result, the fluid discharged from the discharge ports 41, 42 can surely suppress the dynamic pressure thereof, and even if the discharge ports 41, 42 face the opening of the pressure sensitive orifice 28 to the valve chamber 25, the discharge pressure is reduced. Since the dynamic pressure of the fluid discharged from the outlets 41, 42 is not directly transmitted to the pressure sensitive orifice 28, it is possible to reliably prevent the variation in the operating characteristics of the flow rate control device 29 due to the dynamic pressure of the fluid.

In the present embodiment, the fluid discharged from the discharge ports 41, 42 into the valve chamber 25 directly flows into the pressure-sensitive orifice 28, and the dynamic pressure thereof is prevented from being transmitted to the flow control device 29. Chamfering 4 (taper shape) on the discharge ports 41, 42 themselves
Although the example in which 3 is provided has been described, as shown in FIG. 6, two buffer plates 46 are provided at opposite positions on the peripheral portion of the donut-shaped disc.
The dynamic pressure buffering plate 46 provided with a and 46b may be provided at the discharge ports 41 and 42 as shown in FIG. The dynamic pressure buffer plate 46 may have a shape that covers only the discharge ports 41, 42 as shown in FIG. 6 or a shape that covers the circumference of the discharge ports 41, 42 in an annular shape. Further, the discharge ports 41, 42 may be provided with chamfers 43 as shown in FIG. 7 or may have the same inner diameter. In particular, if the chamfer 43 is provided, more excellent effects can be obtained.

Further, in the above embodiment, the vane pump has been described as an example, but a pump having the flow rate adjusting valve 26 and the flow rate control device 29 connected to the electromagnetic control device 35 may be a pump having another structure such as a plunger pump, The same effects as described above can be obtained.

<Effect of Device> As described above, according to the liquid pump of the present invention, the fluid discharged from the throttle portion directly flows into the pressure-sensitive orifice into the flow control valve of the flow control device, and the dynamic pressure of the fluid is controlled. Since the buffer member is provided so as not to be transmitted to the device, there is an advantage that it is possible to reliably prevent the variation in the operating characteristics of the flow rate control device due to the dynamic pressure of the discharge fluid.

[Brief description of drawings]

1 is a side sectional view showing a characteristic part of the liquid pump of the present invention, FIG. 2 is a side sectional view showing an electromagnetic control device of the liquid pump of the present invention, and FIG. 3 is a part of the liquid pump of the present invention. FIG. 4 is a cutaway side view, FIG. 4 is a front sectional view of the liquid pump of FIG. 3, FIG. 5 is a partially cutaway side view of the other part of the liquid pump of FIG. 3, and FIG. FIG. 7 is a perspective view showing a dynamic pressure damping plate according to another embodiment, FIG. 7 is a side sectional view showing an electromagnetic control device having the dynamic pressure damping plate of FIG. 6, and FIG. 8 is a conventional liquid pump. A side sectional view showing a flow control valve device,
FIG. 9 is a side sectional view showing another conventional example. 22 ... Pump section, 23 ... Discharge passage, 25 ... Valve chamber, 26 ... Flow rate adjusting valve, 28 ... Pressure sensitive orifice, 29 ... Flow rate control device, 32 ... Throttling section, 33 ... Valve body, 35 ... Electromagnetic control device, 39 … Valve, 41,42…
Discharge port, 43 ... Chamfer as cushioning member, 46 ... Dynamic pressure cushioning plate as cushioning member.

Claims (1)

[Scope of utility model registration request] 1. A flow rate adjusting valve which is provided in a discharge passage of a liquid pump and adjusts the amount of fluid flowing to the downstream side thereof, and a fluid on the discharge side depending on a pressure difference between the upstream side and the downstream side of the flow rate adjusting valve. A flow rate control device for recirculating a part of the flow rate to the suction side, wherein the flow rate adjusting valve has a throttle portion formed at an opening on the upstream side of the discharge passage, and a fluid discharged from the throttle portion is directly pressure-sensitive to the flow rate control device. A liquid pump comprising a buffer section so as to prevent the dynamic pressure from flowing into the orifice and being transmitted to the flow rate control device.