JPS6325194B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic control device that improves the responsiveness of pressure control using a variable displacement pump.

Conventionally, as this type of hydraulic control device, one shown in FIG. 1, for example, has been used.

In Fig. 1, 1 is a variable discharge amount vane pump, and a load line 2 is the main pipe on the discharge side.
The hydraulic pressure of the load line 2 is supplied from the load line 2 to the remote control relief valve 4 through the throttle 3, and when the pressure of the load line 2 reaches the set pressure, the remote control relief valve 4 is activated to allow oil to flow into the tank 5. , generates a differential pressure ΔP at the throttle 3.

The differential pressure ΔP generated in the throttle 3 is applied as a differential pressure across a pressure compensator valve 6 provided as a pressure control valve, and when the differential pressure ΔP is less than a predetermined value set by a spring 7, the switch shown in the figure is position, and on the other hand, if the differential pressure ΔP exceeds a predetermined value,
The differential pressure ΔP overcomes the spring 7 and switches to the right position.

Pressure control by switching the pressure compensator valve 6 based on the differential pressure ΔP of the throttle 3 is performed via the throttle 8 at the switching position shown in the figure.
By supplying the control hydraulic pressure leading to the variable displacement vane pump 1 from port c to the control actuator 1a of the variable displacement vane pump 1, the vane eccentricity is maximized to achieve the maximum displacement, and the pressure in the load line 2 increases to increase the pressure. When the compensator valve 6 is switched to the right position, ports b and c communicate to connect the control actuator 1a to the tank 5, and therefore, the vane eccentricity is returned to the zero position by the operation of the recovery actuator 1b. The pressure increase in the load line 2 is suppressed by narrowing the discharge amount to around zero, and the pressure of the load line 2 is controlled to the set pressure by repeating the above switching operation.

By the way, the reason why the throttle 8 is provided in the pilot pipe line 9 connected to the port a of the pressure compensator valve is that when the pressure compensator valve 6 is switched to the right position, the port a is also connected to the tank 5. This oil flow obstructs the flow of oil from the control actuator 1a and makes it difficult to return, so the flow in the pilot pipe 9 is suppressed by the throttle 8, and the 1a can return quickly.

However, the throttle 8 of the pilot pipe 9 impairs the oil flow even when attempting to supply control hydraulic pressure to the control actuator 1a at the illustrated switching position, and therefore increases the discharge amount and increases the pressure. This is making the responsiveness worse when trying to do so.

The present invention has been made in view of the above problems, and it improves the flow of oil when hydraulic pressure is supplied to the control actuator of a variable displacement pump, and
The pressure control valve has a built-in throttle that restricts the flow of oil in the line supplying control hydraulic pressure only when the control actuator is switched to communicate with the tank, increasing the responsiveness of pressure control. The purpose is to provide a hydraulic control device.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 2 is a hydraulic circuit diagram showing a basic embodiment of the present invention, which includes a variable discharge amount vane pump 10, a throttle 11 that generates a differential pressure for pressure control, a relief valve 12 for remote control, and a hydraulic circuit diagram showing a basic embodiment of the present invention. The variable discharge amount vane pump 10 is configured with a pressure compensator valve 13 as a pressure control valve to be used.
The maximum discharge amount is obtained by supplying hydraulic pressure to the control actuator 10a, and when the control actuator 10a is communicated with the tank 14, the discharge amount is pushed to zero (minimum discharge amount) by the operation of the recovery actuator 10b.

The pressure compensator valve 13 leads the front and back pressure of the throttle 11 to both sides thereof as pilot pressure, and also branches the pilot pressure led from the load line 15 through a pilot conduit 16 and connects it directly to port a. Further, a throttle 17 for obstructing the flow of oil from the pilot pipe line 16 is built in the right switching position of the pressure compensator valve 13.

Next, the operation will be explained. In the illustrated switching position where the variable discharge amount vane pump 10 has the maximum discharge amount, the control hydraulic pressure from the pilot line 16 is allowed to flow through the pressure compensator valve 13 without being obstructed. directly controlled actuator 1
0a, and drives the vane eccentricity to the maximum position.

Next, when the pressure rise in the load line 15 causes the remote control relief valve 12 to operate and oil to flow into the tank 14, a differential pressure ΔP is generated in the throttle 11, and when this differential pressure ΔP overcomes the spring 18, The pressure compensator valve 13 is switched to the right position. For this reason, the control actuator 10
a communicates with the tank 14, and at the same time the flow of oil from the pilot line 16 is blocked by the throttle 17, so oil is quickly discharged from the control actuator 10a to the tank 14, and the recovery actuator 10a Driven by this, the vane eccentricity is directed to the zero position, and the pressure in the load line is suppressed by restricting the discharge amount.

As described above, according to the device of the present invention, the discharge amount control by switching the pressure compensator valve 13 allows the oil flow to be controlled even when the supply of control oil pressure is switched to, since the oil flow is not obstructed by the throttle or the like. Responsive pressure control can be achieved.

FIG. 3 shows a specific embodiment of the present invention, and particularly clarifies the valve structure of the pressure compensator valve 13. Note that parts corresponding to those in FIG. 2 are denoted by the same reference numerals.

First, to explain the configuration, the variable discharge amount vane pump 10 has a plurality of vanes 20 provided on the circumferential surface of a rotor 19 so as to be able to appear and retract freely by pressure from the inside by a spring. By rotating within, oil is discharged from the outflow port 22. As the means for varying the discharge amount, a control actuator 10a biased by a spring 23 and a recovery actuator 10b directly introducing discharge pressure are provided at positions facing the outer periphery of the cam ring 21. By changing the position of the cam ring 21, the amount of eccentricity l of the rotor 19 with respect to the cam ring 21 changes, and the eccentricity becomes maximum at the position of the rotor 19 shown in the figure, and the maximum discharge amount is obtained.

Next, the pressure compensator valve 13 has a spool 2 which is slidable in the axial direction within the valve body 24.
5, and a spring 2 on the left side of the spool 25.
The valve chambers 27a, 27b, 27c, 27d, 27 are in contact with the valve 6 and house the spool 25.
The valve chambers other than the valve chamber 27e are divided into ports 28a, 28b, and 28f.
c, 28d and 28f are in communication. Further, the spool 25 is provided with valve chambers 27b and 2 at the illustrated positions.
An internal passage 29 having an opening that communicates between 7c and 27e is formed in the axial direction.

On the other hand, a hydraulic cylinder 31 is provided on the load line 15 via a directional switching valve 30 as a control load.

Next, the operation of the pressure compensator valve 13 will be explained.

In the state shown in FIG. 3, the remote control relief valve 12 is closed and no differential pressure ΔP is generated in the throttle 11. Therefore, the hydraulic pressures applied to the valve chambers 27a and 27f are equal, and the spring 26 The spool 25 is switched to the right side by the force.

At this time, from the pilot line 16 to the port 28
The oil introduced into the valve chamber 27b through the valve chamber 27b flows into the valve chamber 27c through the gap between the spool 25 and the valve chamber, is supplied to the control actuator 10a through the port 28c, and moves the cam ring 21 to the maximum position shown in the figure. By pushing it to the eccentric position, the variable displacement vane pump 10 is put into maximum displacement operation.

Next, the relief valve 12 operates due to the pressure increase in the load line 15, allowing oil to flow into the tank 14, and the throttle 11
When the differential pressure ΔP generated in Part is valve chamber 2
When the partition between 7d and 27e is removed, the valve chamber 27c that communicates with the control actuator 10a and the valve chamber 27 that introduces the oil from the pilot pipe 16 are exposed.
b are connected to a valve chamber 27d communicating with the tank 14 via an internal passage 29 of the spool 25, and at the same time, the valve chamber 27c is partitioned off from the valve chamber 27b, so that the oil in the control actuator 10a flows into the tank 1.
4, the cam ring 21 is pushed back toward the zero eccentricity position by the restoration actuator 10b, thereby narrowing down the discharge amount. At this time,
Internal passage 29 communicating valve chambers 27b and 27c
The portion acts as a throttle, and the oil flowing from the control actuator 10a into the tank 14 is not obstructed by the oil from the pilot line 16.

In addition, although the above-mentioned embodiment took a variable discharge amount vane pump as an example of a variable discharge amount pump, the present invention is not limited to this, and even a variable displacement piston pump or a gero rotor pump may be used. good.

As described above, according to the present invention, the configuration allows the pressure to be applied to the control actuator used for controlling the increase in the discharge amount of the variable discharge amount pump without causing any obstruction to the flow by throttling or the like. Direct supply in the first switching position of the compensator valve and the second
When reducing the discharge amount at the switching position, the hydraulic pressure of the control actuator applied to the pump is communicated to the tank, and the flow of control hydraulic pressure from the discharge side is suppressed by a throttle installed in the valve so that the flow to the tank is not obstructed. As a result, it is possible to significantly improve the responsiveness of pressure control when controlling the pressure increase in the load line to the set supply pressure by varying the discharge amount.

[Brief explanation of the drawing]

Figure 1 is a hydraulic circuit diagram showing an example of a conventional device.
Fig. 2 is a hydraulic circuit diagram showing the basic configuration of the present invention;
Fig. 3 is a hydraulic circuit diagram showing a specific embodiment of the present invention together with the structure of a pressure compensator valve and a variable discharge amount vane pump, and Fig. 4 shows another switching state of the pressure compensator valve shown in Fig. 3. FIG. 1, 10...Variable discharge amount vane pump, 1a, 1
0a...Control actuator, 1b, 10b...Recovery actuator, 2, 15...Load line, 6,
13...Pressure compensator valve, 7, 18,
23, 26... Spring, 3, 8, 17... Aperture,
5, 14...Tank, 4,12...Relief valve for remote control, 19...Rotor, 9,16...Pilot pipe line, 20...Vane, 21...Cam ring, 22...Outflow port, 24...Valve body, 25...
Spool, 27a-27f...Valve chamber, 28a-28
d, 28f... Port, 29... Internal passage, 30... Directional switching valve, 31... Hydraulic cylinder.

Claims (1)

[Scope of Claims] 1. A remote control relief that receives hydraulic pressure in a load line 15 via a throttle 11, and when the hydraulic pressure reaches a predetermined value, causes oil to flow into a tank 14 to generate a differential pressure across the throttle 11. a valve 12 and the throttle 1
A pressure control valve 18 that controls the discharge amount to a set pressure by switching the hydraulic pressure supplied to the discharge amount control actuator 10a of the variable discharge amount pump 10 based on the differential pressure generated in step 1. In the device, the pressure control valve 18 is switched when no differential pressure is generated in the throttle 11, and directs the control hydraulic pressure directly from the variable discharge amount pump 10 immediately after discharge to the discharge amount control actuator. 10a to achieve the maximum discharge amount.
and when the differential pressure generated in the throttle 11 exceeds a predetermined value, the control hydraulic pressure of the discharge amount control actuator 10a is communicated with the tank 14 to set the minimum discharge amount, and the variable pressure is switched. A hydraulic control device characterized by having a switching structure with a second switching position provided with a throttle 17 that limits the control hydraulic pressure directly introduced immediately after the discharge of the discharge amount pump 10 and communicates with the tank 14.