JP2605587Y2 - Pressure compensation valve - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure compensating valve used in a hydraulic circuit or the like for distributing and supplying a discharge pressure oil of one hydraulic pump to a plurality of actuators.

[0002]

2. Description of the Related Art The present applicant has previously proposed a pressure compensating valve shown in FIG. The pressure compensating valve 1 has an inlet port 2, an outlet port 3, and first, second, and third ports 6, 8, and 9. Further, a check valve section 5 and a pressure reducing valve section 12 are provided. The check valve unit 5 is provided with a valve 4 that communicates and shuts off the inlet port 2 and the outlet port 3. The pressure reducing valve section 12 has a spool 11. The spool 11 connects the second port 8 and the third port 9 with the pressure of the first port 6. The spool 11 shuts off the second port 8 and the second port 9 by the spring force of the third port 9 and the spring 13. Also spool 11
Is in contact with the valve 4 constituting the check valve section 5. These form a pressure compensating valve.

FIG. 4 shows a conventional hydraulic circuit using the pressure compensating valve. This hydraulic circuit supplies pressure oil discharged from a hydraulic pump to a plurality of actuators. The inlet port 2 and the second port 8 of one pressure compensating valve 1 are connected to a pump discharge line 7. The outlet port 3 is connected to a directional control valve 16. The first port 6 is connected to the load pressure introduction path 18.
The pressure in the load pressure introduction path 18 is the load pressure of the actuator 15. The third port 9 is connected to the load pressure detection path 17. The same applies to the other pressure compensating valve 1 '. Note that the other members will be described by adding “′” to the reference numerals.
The load pressure detecting path 17 is connected to the third of each of the pressure compensating valves 1 and 1 '.
Ports 9 and 9 'are connected. The pressure reducing valve section 12 introduces the discharge pressure of the hydraulic pump 14 to the second port 8, reduces the pressure, and outputs the reduced pressure to the third port 9.

Referring now to FIG. 4, a case where the load pressure of one actuator 15 is high and the load pressure of the other actuator 15 'is low will be described. At first, all the directional control valves 16, 16 'are in the neutral position C. Outlet port 3, first port 6, and third port 9 all have zero pressure. Further, a minimum pump pressure acts on the inlet port 2 and the second port 8. The minimum pump pressure refers to the spring 10 of the cylinder 10A of the discharge pressure control device 10.
a. In this state, the valve 4 and the spool 11 are at the positions shown in the drawing, and all ports are shut off from each other.

Next, only one of the directional control valves 15 is set to the first supply position A or the second supply position B. Here, the load pressure of one actuator 15 is applied to the first port 6 via the load pressure introduction path 18. At this time, the pressure at the first port 6 is higher than the pressure at the third port 9. Further, the load pressure of one actuator 15 acts on the outlet port 3 via the inlet-side conduit 19. Accordingly, the spool 11 moves away from the valve 4 to the right in the drawing.

When the hole 51 of the spool 11 opens to the third port 9, the pump discharge pressure oil communicates from the second port 8 to the third port 9. The pressure oil guided to the third port 9 switches the discharge pressure control valve 10B of the discharge pressure control device 10 to the position D in the drawing via the load pressure detection path 17. At this time, the pump discharge pressure oil shuts off the oil passage to the tank. Discharge pressure control device 1
The discharge pressure of the pump is increased by connecting the extension chamber 10b of the zero cylinder section 10A to the tank 10c. The discharge pressure control valve 10B operates to maintain the difference between the pressure of the load pressure detection path 17 and the pump discharge pressure at a predetermined amount by the spring 10d. The flow rate and the pressure are determined by the discharge pressure control valve 10B.

Thereafter, the increased pump discharge pressure acts on the inlet port 2. Therefore, the pressure acting on the valve 4 is such that the pump pressure acting on the inlet port 2 is higher than the load pressure acting on the outlet port 3. Then, the valve 4 moves rightward in the figure. When the valve 4 opens to the outlet port 3, the inlet port 2 communicates with the outlet port 3. Here, the pressures at the inlet port 2 and the outlet port 3 become equal. The differential pressure between the inlet port 2 and the third port 9 (differential pressure between the pump discharge pressure and the load pressure in the load pressure detection path) △ P1, and the differential pressure between the load pressure acting on the outlet port 3 and the first port 6 (directional control) The differential pressure between the upstream pressure and the downstream pressure of the valve) △ P2. By the operation described above,
The pressure compensating valve 1 is balanced at a position where △ P1 = △ P2, and enters a steady state. Note that ΔP1 is determined by the spring force of the spring 10d of the discharge amount control valve 10B.

Next, a case in which the other actuator 15 'with a lower load is operated from the above steady state will be described. The third port 9 'communicates with the third port 9 via the load pressure detection path 17. Therefore, the pressure is acting on the third port 9 'of the other directional control valve 16' from the state before the operation at the neutral position C. Here, the other directional control valve 16 '
Is switched to the first supply position A or the second supply position B. Since a low load acts on the other actuator 15 ', a low pressure acts on the first port 6'. Since high pressure due to the high load of one actuator 15 is acting on the third port 9 ', the spool 11' is pushed to the left in the figure.

Here, the discharge pressure of the pump 14 acts on the inlet port 2 'equally to the inlet port 2'. The valve 4 ′ is pushed rightward in the drawing by the pressure of the inlet port 2 ′, and the valve 4 ′ is pushed leftward from the spool 11 ′ in the drawing.
The spool 11 'is pushed rightward in the figure via 2'. First
The other actuator 1 having a low load is connected to the port 6 '.
A load pressure of 5 'acts. A high load pressure of one actuator 15 acts on the third port 9 '. As a result, the valve 24 'is pushed leftward by the spool 11', and the opening area (flow rate) of the inlet port 2 'and the outlet port 3' is reduced. As a result, the pressure at the outlet port 3 'becomes a low pressure corresponding to the load pressure of the other actuator 15'.

As described above, the pressure compensating valves 1, 1 'operate to maintain △ P1 = △ P2 in a steady state. Therefore, even when different load pressures act on the actuators 15 and 15 ', the discharge pressure oil of the hydraulic pump can be distributed and supplied at a flow rate.

The pressure compensating valves 1, 1 'distribute a flow rate in accordance with the degree of opening of the directional control valves 16, 16' by maintaining △ P1 = △ P2. The state in which the flow is distributed only by the degree of opening of the directional control valves 16, 16 'regardless of the load on the actuators 15, 15' is referred to as a completely compensated state. The above-mentioned pressure compensating valve, in order to easily realize the state of complete compensation,
The diameter d1 of the valve 4 is equal to the diameter d2 of the spool 11, that is, the pressure receiving area. That is, when there is a pressure receiving area difference, the above △ P1 and △ P2 each consider the pressure receiving area,
It is necessary to design the balance between the forces △ F1 and △ F2. If the pressure receiving areas are the same, only the differential pressure needs to be simply considered.

[0012]

[Problem to be Solved by the Invention] The actuator 1
Let us consider a case where reference numerals 5, 15 'are left and right traveling motors in a hydraulic shovel or the like. When the hydraulic shovel turns left and right, the left and right directional control valves are operated such that there is a difference between the respective opening degrees depending on the turning direction and speed. BACKGROUND ART In a hydraulic shovel, it is known that a higher load is applied to a traveling motor on the opposite side (also referred to as an outside) of a turning direction when performing a turning traveling. When the pressure compensating valve realizes complete compensation, it is possible to make a turning travel only with the opening of the directional control valve independently of the load. It goes without saying that when the opening degrees of the left and right directional control valves are the same, the vehicle goes straight. However, there is a demand for making the flow distributed to the lower load by the left and right traveling motors smaller than in the fully compensated state in order to make the turning traveling easier. In other words, there is a problem that it is desired to realize overcompensation, which is a flow difference larger than the flow distribution irrespective of the load in the fully compensated state.

Accordingly, an object of the present invention is to provide a pressure compensating valve in which the flow rate of the actuator on the high load side is larger than that of the low load state compared to the fully compensated state.

[0014]

A first aspect of the present invention is a pressure compensating valve provided on the upstream side of the directional control valve 46, which passes by the pressure of the pump discharge line 41 and the downstream pressure of the directional control valve 46. The flow rate is controlled so as to increase, and the upstream flow rate of the direction control valve 46 and the pressure of the load pressure detection path 44 are controlled so as to decrease the passing flow rate, and the pressure of the pump discharge pipe 41 and the load pressure detection path 44 are controlled. The difference ΔF1 in force caused by the pressure and the difference ΔF2 in force caused by the upstream pressure and the downstream pressure of the direction control valve 46 are controlled to be the same. The load pressure detection path 44 is smaller than the pressure receiving area, and the load pressure detection is performed.
The pressure in the passage 44 is obtained by reducing the pump pressure.
Is determined by the maximum of the actuator load pressures.
The pressure compensating valve is characterized by being set.

[0015]

According to the second invention, a check valve portion 28 and a pressure reducing valve portion 39 are provided in the valve body 21, and the check valve portion 28 communicates with the inlet port 23 and the outlet port 24 and shuts off the valve 25.
The pressure reducing valve section 39 is provided with first, second, and third ports 29, 30, 31 and a spool 32, and the spool 32 is provided with a second port 3 by the pressure of the first port 29.
0 and the third port 31, and the second port 30 and the third port 31 are shut off by the pressure of the third port 31, and the spring 36 moves in the direction of shutting off the second port 30 and the third port 31. The spool 32 is pushed so that the spool 32 comes into contact with the valve 25, and the diameter of the valve 25 is
2, the outlet port 24 is connected to the inlet side of the directional control valve 46, and the inlet port 23 and the second
The pressure compensating valve is characterized in that a pump discharge pipe line 41 is connected to the port 30 and a load pressure introducing path 43 connected to the outlet side of the direction control valve 46 is connected to the first port 29.

[0017]

[Operation] When a hydraulic circuit that supplies the pressure oil discharged from one hydraulic pump to a plurality of actuators is used as the pressure compensating valve, the flow rate of the pressure compensating valve on the side of the actuator having a large load is equal to the differential pressure ΔP1. Is controlled so that the force ΔF1 that takes into account the pressure difference ΔP2 and the force ΔF2 that takes into account the pressure receiving area are the same. Since the pressure compensating valve on the side of the actuator with a small load has a pressure receiving area of the pressure of the pump discharge pipe 41 smaller than the pressure receiving area of the pressure of the load pressure detecting path 44, the passing flow rate is small. In other words, even though the force balance is the same as that at the time of complete compensation, the opening from the pump discharge pipe 41 to the directional control valve 46 is reduced to reduce the pressure by the larger pressure receiving area,
The upstream flow rate of the resultant directional control valve 46 is reduced.

Thus, the actuator on the high load side becomes a pressure compensating valve larger than the flow rate of the actuator on the low load side.

When a pressure compensating valve is used in a hydraulic circuit that supplies the pressure oil discharged from one hydraulic pump to a plurality of actuators, the pressure compensating valve on the side of the actuator having a large load has its valve 25 controlled by the pressure of the inlet port 23. It moves toward the spool 32 and connects the inlet port 23 and the outlet port 24. At the same time, the spool 32 is pushed by the valve 25 to connect the second port 30 and the third port 31. In the pressure compensating valve on the actuator side with a small load, the first port 29
Is smaller than the sum of the force of the third port 31 acting on the spool 32 and the spring force of the spring 36. The spool 32 is pushed in a direction toward the valve 25. The valve 25 has a sum of a force pushed by the spool 32 and a force acting on the valve 25 due to the pressure of the outlet port 24;
The opening area of the inlet port 23 and the outlet port 24 is determined by balancing the pressure of the inlet port 23 with the force acting on the valve 25. At this time, since the pressure receiving area of the pressure in the pump discharge line 41 is smaller than the pressure receiving area of the load pressure detecting path 44, the opening areas of the inlet port 23 and the outlet port 24 are the same (complete compensation). Smaller than.

As described above, the flow rate difference between the actuator on the high load side and the actuator on the low load side is larger than in the fully compensated state.

[0021]

FIG. 1 shows a pressure compensating valve according to the present invention. The pressure compensating valve 20 has a valve body 21 having an inlet port 23, an outlet port 24, and first, second, and third ports 29, 30, and 31. Further, a check valve section 28 and a pressure reducing valve section 39 are provided. The check valve section 25 is provided with a valve 25 that communicates and shuts off the inlet port 23 and the outlet port 24. The pressure reducing valve section 39 has a spool 32.
The spool 32 is moved to the second port 30 by the pressure of the first port 29.
And the third port 31. The spool 32 is the third
The second port 30 and the second port 31 are shut off by the spring force of the port 31 and the spring 36. Also, the spool 32 has a push rod 37.
The push rod 37 is in contact with the valve 25 constituting the check valve section 28. These form a pressure compensating valve.

FIG. 2 shows a hydraulic circuit using the pressure compensating valve. The inlet port 23 and the second port 30 of one pressure compensating valve 20 are connected to a pump discharge line 41 of a hydraulic pump 40. The outlet port 24 is connected to a directional control valve 46. The first port 29 is connected to the load pressure introduction path 43. The pressure in the load pressure introducing passage 43 is the load pressure of the actuator 45. The third port 31 is connected to the load pressure detection path 44.

The same applies to the other pressure compensating valve 20 '. Note that the other members will be described by adding “′” to the reference numerals. The load pressure detecting path 44 communicates with the third ports 31, 31 'of the pressure compensating valves 20, 20'. Pressure reducing valve section 3
9 introduces the discharge pressure of the hydraulic pump 41 to the second port 30, reduces the pressure, and outputs it to the third port 31.

Referring now to FIG. 2, a case where the load pressure of one actuator 45 is high and the load pressure of the other actuator 45 'is low will be described. Initially, all the directional control valves 46 and 46 'are in the neutral position C. The pressure is 0 in all of the outlet port 24, the first port 29, and the third port 31. Further, a minimum pump pressure acts on the inlet port 23 and the second port 30. The minimum pump pressure is determined by the spring 34a of the cylinder 34A of the discharge pressure control device 34. In this state, valve 2
5. The spool 32 is at the position shown in the figure, and all ports are shut off from each other.

Next, only one of the directional control valves 46 is set to the first supply position A or the second supply position B. Here, the load pressure of one actuator 45 acts on the first port 29 via the load pressure introduction path 43. At this time, the first port 2
The pressure at 9 is higher than the pressure at the third port 31. The load pressure of one actuator 45 passes through the inlet pipe 42 and acts on the outlet port. Accordingly, the spool 32 moves to the right in the drawing away from the valve 25.

When the hole 38 of the spool 32 opens to the third port 31, the pump discharge pressure oil flows from the second port 30 to the third port 31.
Connects to port 31. The pressure oil guided to the third port 31 switches the discharge pressure control valve 34B of the discharge pressure control device 34 to the position D in the drawing via the load pressure detection path 44. At this time, the pump discharge pressure oil shuts off the oil passage to the tank. The discharge pressure of the pump increases when the extension chamber 34b of the cylinder portion 34A of the discharge pressure control device 34 communicates with the tank 34c. The discharge pressure control valve 34B is connected to a load pressure detection path 44 by a spring 34d.
An operation of maintaining a difference ΔF1 between the force due to the pressure of (1) and the force due to the pump discharge pressure at a predetermined amount. The flow rate and the pressure are determined by the discharge pressure control valve 34B.

Thereafter, the increased pump discharge pressure acts on the inlet port 23. Therefore, the pressure acting on the valve 25 is
The inlet port 23 is lower than the load pressure acting on the outlet port 24.
The pump pressure acting on the air becomes higher. Then, the valve 25 moves rightward in the figure. When the valve 25 opens to the outlet port 24, the inlet port 23 communicates with the outlet port 24. Here, the pressures at the inlet port 23 and the outlet port 24 become equal.

The difference between the force between the inlet port 23 and the third port 31 is ΔF1, and the difference between the force between the outlet port 24 and the first port 29 is ΔF2. By the operation described above, the pressure compensating valve 2
0 balances at a position where △ F1 = △ F2, and enters a steady state. The operation of the above-described pressure compensating valve is the same as that of the prior art.

In the present invention, the diameter d1 of the valve 25 is
2 is smaller than the diameter d2. The operation according to this will be described below. A case in which the other actuator 45 'with a lower load is operated from the steady state will be described. The third port 31 ′ is connected to the third port 3 via a load pressure detection path 44.
Communicates with 1. Therefore, from the state before the operation, which is the neutral position C, the third port 31 'of the other pressure compensating valve 20'.
Has the same pressure acting as the third port 31 of one pressure compensating valve 20. Here, the other directional control valve 46 'is switched to the first supply position A or the third supply position B. Since a low load is acting on the other actuator 45 ',
A low pressure acts on the first port 29 '. Third port 3
Since high pressure due to the high load of one actuator 45 is acting on 1 ', the spool 32' is pushed to the left in the figure.

Here, the pump 40 is connected to the inlet port 23 '.
Discharge pressure acts on the inlet port 23 equally. The valve 25 'is pushed rightward in the figure by the pressure of the inlet port 23', and the valve 25 'pushes the spool 32' rightward in the figure via a pushing rod 37 'projecting leftward in the figure from the spool 32'. Push. As described above, one pressure compensating valve 20 acts to maintain ΔF1 = ΔF2 in a steady state.

However, since the diameter d1 of the valve 25 is smaller than the diameter d2 of the spool 32, the pressure receiving area on which the pressure (pump discharge pressure) of the pump discharge circuit 41 of the valve 25 acts depends on the load pressure detecting path 44 of the spool 32. It is smaller than the pressure receiving area on which the load pressure acts. Here, in the other pressure compensating valve 20 ', the force for pushing the spool 32' to the left is the same as that of the other conventional pressure compensating valve 1 'shown in FIGS.
The force for pushing the valve 25 'of the other pressure compensating valve 20' rightward is smaller than that of the conventional pressure compensating valve 1 'of FIGS. Thus, in the other pressure compensating valve 20 ', the valve 25' is connected to the other pressure compensating valve 1 'shown in FIGS.
To the left of the valve 4. Therefore, the inlet port 23 '
And the opening area of the outlet port 24 'becomes smaller than that of the conventional pressure compensating valve. That is, the other pressure compensating valve 20 'realizes an overcompensated state in which the flow distribution is reduced.

Therefore, the flow rate from the inlet port 23 'to the outlet port 24' of the other pressure compensating valve 20 'is smaller than that of the conventional pressure compensating valve.

The case where the actuators 45 and 45 'shown in FIG. 2 are left and right traveling motors of a hydraulic shovel will be described.
For example, when making a right turn (turning forward in the right direction), a larger load is applied to the left running motor, which is on the opposite side to the turning direction, than to the right running motor. As described above, the right running motor 45 '
The opening of the valve 25 'of the pressure compensating valve 20' connected to the valve becomes small. Therefore, the flow rate passing through the pressure compensating valve 20 'on the right side of the state of the complete compensation becomes smaller. As a result, the left running motor with a high load rotates relatively faster than the conventional fully compensated state, and is easier to turn.

[0034]

As described above, the present invention has realized a pressure compensating valve for distributing and supplying the discharge pressure oil of one hydraulic pump to a plurality of actuators. Also, an overcompensated pressure compensating valve has been realized in which the flow rate distributed to the actuator with a lower load is even smaller than in the fully compensated state. As a result, the flow rate of the actuator on the high load side becomes larger than that on the low load side as compared with the fully compensated state.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a pressure compensating valve according to the present invention.

FIG. 2 is a hydraulic circuit diagram using the pressure compensating valve of the present invention.

FIG. 3 is a sectional view showing a conventional pressure compensating valve.

FIG. 4 is a hydraulic circuit diagram using a conventional pressure compensating valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Pressure compensation valve 2 ... Inlet port 3 ... Outlet port 4 ... Valve 5 ... Check valve part 6 ... First port 8 ... Second port 9 ... Third port 10 ... Discharge pressure control device 11 ... Spool 12 ... Pressure reducing valve part DESCRIPTION OF SYMBOLS 13 ... Spring 14 ... Hydraulic pump 15 ... Actuator 16 ... Direction control valve 17 ... Load pressure detection circuit 18 ... Load pressure introduction path 20 ... Pressure compensating valve 21 ... Valve body 23 ... Inlet port 24 ... Outlet port 28 ... Check valve part 29 ... first port 30 ... second port 31 ... third port 32 ... spool 36 ... spring 39 ... pressure reducing valve part 40 ... hydraulic circuit 41 ... pump discharge pipeline 43 ... load pressure introduction path 44 ... load pressure detection path 45 ... actuator 46 ... directional control valve

Continuation of the front page (56) References JP-A-1-176803 (JP, A) JP-A-60-14604 (JP, A) JP-A-4-244605 (JP, A) WO 91/5958 (WO, A1) (58) Field surveyed (Int. Cl. ⁷ , DB name) F15B 11/05 F15B 11/00

Claims (2)

(57) [Scope of request for utility model registration] 1. A pressure compensating valve provided upstream of a direction control valve (46), wherein the pressure is controlled by a pressure of a pump discharge pipe line (41) and a pressure of a downstream side of the direction control valve (46) so as to increase a passing flow rate. The flow rate is controlled so as to reduce the passing flow rate by the upstream pressure of the control valve 46 and the pressure of the load pressure detection path 44, and the difference ΔF 1 between the pressure of the pump discharge pipe 41 and the pressure of the load pressure detection path 44 is obtained. Is controlled so that the difference ΔF2 in force between the upstream pressure and the downstream pressure of the direction control valve 46 is equalized, and the pressure receiving area of the pressure in the pump discharge pipe 41 is changed to the load pressure detection path 4.
4 is smaller than the pressure receiving area, and the pressure of the load pressure detecting path 44 is reduced by reducing the pump pressure.
And the largest of the load pressures of the actuators
A pressure compensating valve characterized by being determined by pressure. 2. A valve body 21 is provided with a check valve portion 28 and a pressure reducing valve portion 39, wherein the check valve portion 28 has an inlet port 23 and an outlet port 2.
The pressure reducing valve portion 39 is provided with first, second and third ports 29 and 3.
0, 31 and a spool 32. The spool 32 communicates the second port 30 and the third port 31 with the pressure of the first port 29, and the third port 31
The spring 36 pushes the spool 32 in a direction to shut off the second port 30 and the third port 31, and the spool 32 contacts the valve 25. The diameter of the valve 25 is smaller than the diameter of the spool 32, the outlet port 24 is connected to the inlet side of a directional control valve 46, and a pump discharge line 41 is connected to the inlet port 23 and the second port 30. And the load pressure introducing passage 4 connected to the outlet side of the directional control valve 46.
3. A pressure compensating valve, characterized in that 3 is connected to a first port 29.