JPH0587426B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a pump device driven by an automobile engine or the like.

<Prior Art> In a pump device that is driven by a drive source whose rotational speed fluctuates, such as an automobile engine, and supplies working fluid to a fluid pressure actuator such as a power steering device, for example, as shown in FIG. Pressure oil discharged from the discharge port 5 of the hydraulic pump 2 driven by the automobile engine 1 flows into the inflow port 6 of the flow control valve 3, and the spool is pressed by a fixed throttle 10 and a spring 9. 8 diverts surplus fluid of a predetermined flow rate or more to the bypass port 7,
The diverted surplus fluid is returned to the suction port 11 of the hydraulic pump 2, and the fluid discharged from the hydraulic actuator 4 is returned to the reservoir 12. Therefore, a super charge mechanism 13 is provided for sucking the insufficient fluid from the reserve 12 into the bypass port 7.

<Problems to be Solved by the Invention> However, in the conventional device described above, a large amount of surplus fluid is diverted to one bypass port during high-speed rotation, so only a portion of it is involved in supercharge, resulting in insufficient suction. There was a problem in that cavitation occurred and erosion occurred in the rotor, plate, etc. of the hydraulic pump, reducing durability.

<Means for Solving the Problems> In order to solve the above-mentioned conventional problems, the present invention provides a hydraulic pump driven by an automobile engine, etc., and a system that uses pressure oil discharged from the hydraulic pump as a fluid. A pump device comprising a flow control valve that controls the flow rate to a predetermined flow rate required for a pressure actuator and returns excess flow to the suction port of a hydraulic pump from a bypass passage, and a super charge mechanism that sucks reservoir fluid into the bypass passage of the flow control valve. , a bypass flow control valve is provided between the hydraulic pump and the flow control valve, a bypass passage of the bypass flow control valve is connected to an inlet of the hydraulic pump, and a super charge is configured to suck reservoir fluid into the bypass passage. It is equipped with a mechanism.

<Function> In the present invention, when the hydraulic pump rotates at high speed, the bypass flow control valve opens to bypass surplus fluid to the suction port of the hydraulic pump, and the flow rate of this surplus fluid is used to charge the super charge mechanism provided in the bypass flow control valve. The reservoir fluid is sucked into the bypass port to compensate for the insufficient bypass flow rate of the flow control valve and improve suction efficiency during high-speed rotation.

<Example> Hereinafter, an example of the present invention will be described based on FIGS. 1 and 2. In FIG. 1, 1 is an automobile engine, 2 is a hydraulic pump rotationally driven by the automobile engine 1, 5 is a pressure oil discharge port,
11 is an inlet. Reference numeral 3 denotes a flow rate control valve, which includes a pressure oil inflow port 6, a bypass port 7 connected to the suction port 11 of the hydraulic pump 2, a spool 8, a spring 9, and a fixed throttle 10, and controls the conventional flow rate shown in FIG. Same as control valve. 4 is a fluid pressure actuator, 12 is a reservoir, and 13 is a super charge mechanism.

In the present invention, a bypass flow control valve 14 is disposed between the hydraulic pump 2 and the fluid control valve 3, and a super charge mechanism 20 is also provided on the bypass flow control valve 14.

To explain in more detail, the bypass flow control valve 14, like the flow control valve 3, includes a pressure oil inflow port 15, a bypass port 16, and a spring 1.
It is composed of a spool 17 pressed by a spool 8 and a fixed throttle 19. The pressure oil inflow port 15
is connected to the discharge port 5 of the hydraulic pump 2, and the bypass port 16 is connected to a circuit connected to the bypass port 7 of the flow rate control valve 3 and the suction port 11 of the hydraulic pump 2. In addition, the bypass flow control valve and the flow control valve 3 are the bypass flow control valve 1.
4 and the pressure oil inlet port 6 of the flow control valve 3. Here, the throttle area A of the fixed throttle 19 of the bypass flow control valve 14 and the throttle area A of the fixed throttle 10 of the flow control valve 3
The throttle area B of the fixed throttle 10 of the flow rate control valve 3 has a relationship of B>A.

Further, the bypass port 16 of the bypass flow control valve 14 is provided with a supercharge mechanism 20 that sucks reservoir fluid from the reservoir 12.

Next, the operation of the above configuration will be explained. When the hydraulic pump 2 rotates at low speed, the discharge flow rate of pressure oil is small, so the bypass flow control valve 14 is not activated.
The flow rate control valve 3 alone controls the flow rate to a predetermined flow rate required by the fluid pressure actuator 4, thereby providing normal pump performance.

When the rotation of the hydraulic pump 2 increases and the discharge amount increases, the bypass flow control valve 14 operates in proportion to the rotation speed due to the differential pressure of the fixed throttle 19.
The bypass port 16 is opened to return excess fluid to the suction port 11 of the hydraulic pump 2, and the fluid in the reservoir 12 is sucked into the bypass port 16 by the supercharge mechanism using this bypass flow rate.

The flow control valve 3 is also operated by the differential pressure of the fixed throttle 10,
Excess fluid is returned from the bypass port 7 to the suction port 11 of the hydraulic pump 2, including the supercharge action of the supercharge mechanism 13.

Therefore, as shown in FIG. 2, the flow rate Q returned to the suction port 11 of the hydraulic pump 2 is changed to the bypass flow rate Y based on the throttle area B of the fixed throttle 10 in the flow rate control valve 3 due to the increase in rotational speed, as shown in FIG. A bypass flow rate X based on the throttle area A of the fixed throttle 19 by the flow rate control valve 14 is added, increasing the suction efficiency during high-speed rotation.

If one bypass port is equipped with a supercharge mechanism as in the past, when the bypass flow rate increases, the suction resistance increases, the suction efficiency of the reservoir fluid deteriorates, and the supercharge function deteriorates.However, as described above, the bypass port By dividing the bypass ports 7 and 16 into two locations, the suction resistance of the bypass ports 7 and 16 from the reservoir 12 is reduced.
This increases the suction of fluid within the reservoir 12 and increases the proportion of fluid involved in supercharge.

<Effects of the Invention> As described above, the present invention provides a bypass flow control valve equipped with a super charge mechanism between the hydraulic pump and the flow control valve in a conventional pump device composed of a hydraulic pump and a flow control valve. established,
Since the configuration is such that the bypass flow rate between the flow control valve and the bypass flow control valve is returned to the suction port of the hydraulic pump, the suction efficiency during high-speed rotation of the hydraulic pump is increased and the proportion of fluid involved in super charge is increased. Therefore, it has the effect of resolving insufficient suction during high-speed rotation, and preventing cavitation and erosion of the hydraulic pump, as well as pulsation and noise caused by cavitation.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of the present invention, FIG. 2 is a bypass flow characteristic diagram according to the present invention, and FIG. 3 is a conventional circuit diagram. 1...Automotive engine, 2...Hydraulic pump,
3...Flow control valve, 4...Fluid pressure actuator, 5...Discharge port, 7...Bypass port, 11
... Suction port, 12 ... Reservoir, 13 ... Super charge mechanism, 14 ... Bypass flow control valve,
16...Bypass port, 20...Super charge mechanism.

Claims (1)

[Claims] 1 A hydraulic pump driven by an automobile engine, etc., and a flow rate that controls the pressure oil discharged from this hydraulic pump to a predetermined flow rate required for a fluid pressure actuator and returns excess flow to the intake port of the hydraulic pump through a bypass passage. In a pump device including a control valve and a super charge mechanism that sucks reservoir fluid into a bypass passage of the flow control valve, a bypass flow control valve is provided between the hydraulic pump and the flow control valve, and the bypass flow rate is A pump device characterized in that a bypass passage of a control valve is connected to an inlet of a hydraulic pump, and a supercharge mechanism is provided for sucking reservoir fluid into the bypass passage.