JP2550774Y2 - Direction control valve device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a directional control valve device for supplying discharge pressure oil of a hydraulic pump to a plurality of actuators by a plurality of directional control valves.

[0002]

2. Description of the Related Art To supply hydraulic pressure oil discharged from a hydraulic pump to a plurality of actuators, the same number of directional control valves as the actuators are provided, and the directional control valves are switched to supply the hydraulic pressure oil discharged from the hydraulic pump to each actuator. Supplying. As the directional control valve, for example, as shown in FIG. 1, a spool 3 is inserted into a spool hole 2 of a valve block 1 and the pump port 4 is slid left and right to connect a pump port 4 to a first port.
It is known that one of the second actuator ports 5 and 6 communicates with the other and the other of the first and second actuator ports 5 and 6 communicates with the tank port 7.

[0003]

In such a directional control valve, as shown in FIG. 1, a valve block is provided as shown in FIG. 1 so as to regulate the maximum pressure of the first and second actuator ports 5 and 6 so that each part is not damaged. First, first and second safety valves 8 and 9 are attached to first and second actuator ports 5 and 6 by opening. As described above, since two safety valves are required for one directional control valve, when a plurality of directional control valves are combined into a directional control valve device, twice as many safety valves as directional control valves are required. Not only is the cost increased, but also the entire directional control valve device is large, and the installation area is large.

Therefore, an object of the present invention is to provide a directional control valve device which can solve the above-mentioned problems.

[0005]

A directional control valve which slidably fits a main spool 49 into a spool hole 31 of a valve block 30 to communicate / block an input port 44 with first and second actuators 34 and 35. The valve block 30 is provided with first and second pressure detection ports 100 and 101 communicating with the first and second actuator ports 34 and 35, and the first and second pressure detection ports 100 and 101 are connected to the valve block. 30 is provided with a ball 103 which opens into the communication recess 102 formed on one of the joint surfaces and prevents the flow of pressure oil from the communication recess 102 to the pressure detection port.
02 and the other joint surface of the valve block 30
4, and a plurality of valve blocks 30 are joined to form the first
The second pressure detection ports 100 and 101 are communicated with the through holes 104, and a spring 106 for pressing the ball 103 is provided between the adjacent valve blocks 30.
3, a cover block 110 is provided on one of the joining surfaces, and a spring force adjusting mechanism 111 for adjusting the pressing force of the ball 103 is provided on the cover block 110.
4 is a directional control valve device that communicates with one safety valve 105.

[0006]

[Operation] A plurality of valve blocks 30 are attached to the front and rear surfaces 40, 41.
When the first and second pressure detection ports 100 and 101 of each valve block 30 are connected to each other by overlapping each other,
Since the high pressure oil does not flow into the pressure detection port 1002 communicating with the safety valve 105 and on the low pressure side 101, the highest pressure of the actuator ports in the plurality of directional control valves can be guided to one safety valve, and the directional control can be performed. It is only necessary to attach one safety valve to the valve device. Not only the number of safety valves is reduced and the cost is reduced, but also the actuator is compact and can be installed in a narrow space, and is connected to a specific direction control valve at the end. Can be adjusted by the spring adjustment mechanism.

[0007]

[Embodiment] FIG. 2 is a circuit diagram of a pressure oil supply device in which a plurality of directional control valves are simultaneously operated to supply discharge pressure oil of one hydraulic pump to each actuator at a predetermined distribution ratio. A plurality of directional control valves 22 are provided in a discharge path 21 of the hydraulic pump 20, and a pressure compensating valve 25 including a check valve portion 23 and a pressure reducing valve portion 24 is provided on the inlet side of each of the directional control valves 22. When the valves 22 are simultaneously operated, the pressure is compensated by the respective pressure compensating valves 25 and the respective actuators 26
The directional control valve 22 and the pressure compensating valve 25 are provided in a valve block to be described later, and the directional control valve 27 is formed by superimposing the valve blocks. As shown in FIG. 3, the valve block 30 has a substantially rectangular parallelepiped shape, and a spool hole 31 is formed near the upper portion of the valve block 30 by opening the left and right side surfaces 32 and 33. The second actuator ports 34 and 35 are formed in the upper surface 36 so as to open. The lower portion of the valve block 30 has a check valve hole 37 opened in the left side surface 32 and a pressure reducing valve hole 38 opened in the right side surface 33. Are formed concentrically, and a pump port 39 opened in the check valve hole 37 is provided with front and rear surfaces 40,
The first and second ports 42 and 43 are formed in the front and rear surfaces 40 and 41 and are formed in the front and rear surfaces 40 and 41.
When 0 and 41 are butt-connected, each pump port, 1st
-The second ports 39, 42 and 43 communicate with each other. As shown in FIG. 4, the valve block 30 has an input port 44 opened in the spool hole 31, first and second load pressure detection ports 45 and 46, the first and second actuator ports 34 and 35, , The second tank port 47, 4
8, first and second pressure detection ports 100 and 101 are formed to open to the first and second actuator ports 34 and 35, and the first and second pressure detection ports 100 and 101 are valve blocks as shown in FIG. A plurality of valves 103 are provided in the communication recess 102 formed in the front surface 40 of the fuel cell 30, and provided with balls 103 constituting check valves. The communication recess 102 and the rear surface 41 are formed with through holes 104. When the front and rear surfaces 40 and 41 of the block 30 are overlapped with each other, as shown in FIG. 5, the first and second pressure detection ports 100 and 101 of each valve block 30 communicate with the communication recess 102 and the through hole 104, respectively, and The ball 103 prevents high pressure from flowing into the low pressure side pressure detection port 100 or 101, and the first and second pressure detection ports 100 of each valve block 30 The highest pressure is introduced at 101, the through hole 104 are communicated with the inlet side of the safety valve 107 provided in one valve block 30 as shown in FIG.

The ball 103 serving as the check valve is provided with a first and second pressure detecting ports 100 and 10 by a spring 106 provided in a concave portion 105 formed on the rear surface 41 of the valve block 30.
When the ball 103 is pressed against the peripheral edge of the opening of the first and second pressure detecting ports 100 and 101, the ball 103 is separated from the peripheral edges of the opening of the first and second pressure detecting ports 100 and 101 when a force greater than the pressing force of the spring 106 acts. Since the communication recess 101 communicates with the communication 101, the pressure at which the check valve is opened is determined by the spring force of the spring 106 and the set pressure of the safety valve 107, and the first or second high pressure detection port 100, 1
When the pressure of 01 becomes equal to or higher than the pressure at which the check valve is opened, the check valve is opened, and the high-pressure first or second pressure detection port 100, 101 communicates with the communication concave portion 102, but the first pressure detection port 102 on the low pressure side. Second pressure detection port 100, 101
Is closed by the ball 103 and cut off from the communication recess 102. Accordingly, the maximum operating pressure of the actuator can be increased by increasing the safety valve set pressure. However, since the spring 106 is disposed in the small recess 105, the spring force cannot be increased, and the spring force cannot be adjusted. The maximum operating pressure cannot be higher than the safety valve set pressure, and the maximum operating pressure cannot be adjusted. For this reason, the maximum operating pressure of the specific actuator to which the pressure oil is supplied by one specific directional control valve of the plurality of directional control valves cannot be higher than the other actuators to which the pressure oil is supplied by the other directional control valves. And cannot be adjusted. To this end, as shown in FIGS. 5 and 6, a cover block 110 is attached to the front surface 40 of the end valve block 30, and a spring force adjusting mechanism 111 is attached to the cover block 110. The spring force adjusting mechanism 111 presses the pressing piston 113 inserted into the hole 112 of the cover block 110 against the ball 103 with the spring 114, and
15 is screwed into the threaded portion 112a of the hole 112 and locked by the lock nut 116.
By loosening the spring 16 and tightening the spring receiver 115, the spring 11
If the force of pressing the ball 103 against the peripheral edges of the first and second pressure detection ports 100 and 101 is increased by increasing the spring force of No. 4, the pressure at which the check valve opens increases, and the valve block at the end is increased. The maximum operating pressure of a specific actuator to which pressure oil is supplied by the 30 specific directional control valves can be made higher than the safety valve set pressure and higher than the maximum operating pressure of other actuators. The maximum working pressure can be adjusted. The main spool 49 fitted in the spool hole 31 has first and second small diameter portions 50 and 51 and a communication groove 52 formed therein, and the first and second load pressure detection ports 45 and 46 are shown in FIG. As shown in FIG. 5, an oil passage 54 is formed in the main spool 49 so as to communicate with and shut off the second load pressure detection port 46 and the second tank port 48. The spool 49 is closed at a neutral position A where the second load pressure detection port 46 and the second tank port 48 communicate with each other through the oil passage 54, and slides the spool 49 rightward to the second small diameter. The portion 51 communicates the second actuator port 35 with the second tank port 48, the communication groove 52 connects the input port 44 with the second load pressure detection port 46, and the first small diameter portion 50 defines the first actuator port 34.
Is connected to the first load pressure detection port 45 and the second load pressure detection port 46 and the second tank port 48 are disconnected.
When the pressure oil supply position B is reached and the spool 49 slides to the left, the first actuator port 34 communicates with the first tank port 47 at the first small-diameter portion 50, and the input port 44 communicates with the first load pressure at the communication groove 52. The second actuator port 35 communicates with the second load pressure detection port 46 at the second small diameter portion 51, and communicates with the second load pressure detection port 46.
Pressure oil supply position C where the pressure and the second tank port 48 are cut off.
Thus, the direction control valve 55 is configured. The check valve hole 37 is opened to the pump port 44 through the oil passage 56, and a valve 60 for shutting off the communication between the pump port 39 and the input port 44 is fitted into the check valve hole 37.
Reference numeral 0 denotes a stopper rod 62 provided on the plug 61, which is regulated so as not to slide leftward from the position shown in the figure, and is held at the shut-off position to constitute the check valve portion 63. Hole 3 for pressure reducing valve
Reference numeral 8 denotes a fourth port 57 and an oil passage 58 which communicate with the second load pressure detecting port 46. A spool 64 is inserted into the pressure reducing valve hole 38 to form a first pressure chamber 65 and a second pressure chamber 66. And
The first pressure chamber 65 communicates with the third port 57, and the second pressure chamber 66 communicates with the second port 43, between the free piston 68 inserted into the blind hole 67 of the spool 64 and the bottom of the blind hole 67. A spring 69 is provided so that the free piston 68 abuts on the plug 70, and a push rod 71 integrally provided on the spool 64 projects from the through hole 72 to abut the valve 60 on the stopper rod 62. A small hole 73 communicating the first port 42 with the blind hole 67 is formed in 64 to form a pressure reducing valve portion 74, and the pressure reducing valve portion 74 and the check valve portion 63 constitute a pressure compensating valve 75. I have.

As described above, a plurality of valve blocks 3
By superimposing and connecting 0, the highest pressure of the actuator port is introduced into one safety valve, so that a single safety valve can be used in a directional control valve device having a plurality of directional control valves. The maximum operating pressure of the actuator by the directional control valve can be made higher than the safety valve set pressure to be higher than the maximum operating pressure of the actuator by the other directional control valves, and the maximum operating pressure can be adjusted.
Further, if the plurality of valve blocks 30 are connected by overlapping the front and rear surfaces 40 and 41 with each other, the pump port and the first and second ports 39, 42 and 43 of each valve block 30 communicate with each other, and the concave portion 53 is adjacent. Since the first and second load pressure detection ports 45 and 46 communicate with each other by being closed at the rear surface 41 of the valve block 30, the discharge path 81 of the hydraulic pump 80 is connected to the pump port 39 and the first port 42 as shown in FIG. If the load and pressure detection path 82 are connected to the second port 43 and connected, a hydraulic circuit similar to that of FIG. 2 can be configured as shown in FIG. In FIG.
83 is a swash plate for controlling the discharge flow rate of the hydraulic pump 80;
Is a servo cylinder, 85 is a directional control valve for pump adjustment, 8
6 is a tank and 87 is a spring.

Next, the operation of the above-described hydraulic circuit will be described with reference to FIG. When the direction control valve 55 is at the neutral position A. The oil sucked from the tank 86 by the hydraulic pump 80 is guided to the pressure chamber a in the opening direction of the check valve 63 through the discharge path 81. At this time, since both the pressure chambers 65 and 66 of the pressure reducing valve part 74 are in communication with the tank 86, the pressures in the pressure chambers 65 and 66 are both zero, so that the pressure reducing valve part 74 is pushed by the weak spring 69. Only the rod 71 is in contact with the check valve portion 63. On the other hand, the pump discharge pressure is maintained at a constant pressure difference from the pressure in the load pressure detection path 82 by the spring 87 of the pump adjustment direction control valve 85. Now, assuming that the differential pressure is 20 kg / cm ² , the pressure in the load pressure detecting path 82 is zero, and the pump discharge pressure is 2 kg / cm 2.
The stroke rises to 0 kg / cm ^2, and at the same time, the pump discharge pressure flows into the pressure chamber a of the check valve portion 63 and the stroke until the inlet pressure of the directional control valve 55 (the outlet pressure of the check valve portion 63) becomes equal to the pump discharge pressure. And if equal, the weak spring 6
Receipt by 9 The pressure reducing valve 74 communicates the pump discharge passage 81 with the pressure chamber 66 only at the stroke end, while the check valve 63 communicates the pump discharge passage 81 with the outlet before reaching the stroke end. When the control valve 55 is at the neutral position A, the pump discharge passage 81 and the pressure chamber 66 do not communicate with each other, and the pressure chamber 65
Pressure remains at zero.

Only one of the directional control valves 55 is the first
When making a stroke to the pressure oil supply position B. Now, the left directional control valve 55 is stroked to the first pressure oil supply position B, and the right directional control valve 55 is in the neutral position A. Move the direction control valve 55 to the stroke and
And the first actuator port 34, and at the same time,
Second actuator port 35 and second tank port 48
To connect. At this time, if the pressure (load pressure) in the conduit 89 connecting the first actuator port 34 and the actuator 88 is higher than the pump discharge pressure (20 kg / cm ² ), the check valve 63 receives the pressure in the pressure chamber b. , The natural descent of the actuator 88 can be prevented. The pressure in the conduit 89 of the actuator 88, that is, the load pressure, is supplied from the passage 58 to one of the pressure chambers 6 of the pressure reducing valve 74.
It is led to 5. Since the pressure in the other pressure chamber 66 is zero, the pressure reducing valve part 74 strokes in the direction in which it is dissociated from the check valve part 63 to the stroke end, and the pressure reducing valve part 74
Pump discharge path 81 and load pressure detection path 82
Communicate. When the pressure (load pressure) in the conduit 89 is higher than the pump discharge pressure (= 20 kg / cm ² ), the check valve section 63 closes at the pressure in the pressure chamber b, and the pressure is reduced to one of the pressure reducing valve sections 74. Since the pressure chamber 65 is guided to the pressure chamber 65, even if the other pressure chamber 66 and the pump discharge path 81 communicate with each other, the pressure reducing valve section 74 remains in a stroke. On the other hand, the pressure (load pressure) in the conduit 89 is the pump discharge pressure (= 20 kg / cm ² ).
When it is smaller, the load pressure is guided to one pressure chamber 65 of the pressure reducing valve portion 74, and the pressure reducing valve portion 74 is
When the pressure in the other pressure chamber 66 increases to the pressure in one pressure chamber 65 (that is, the load pressure), the stroke is closed by the weak spring 69 and the valve 66 is in contact with the check valve 63. In any case, the pressure-reducing valve unit 74 allows the pump discharge passage 81 and the pressure chamber 66 to communicate with each other until the pressure in one pressure chamber 65 and the pressure in the other pressure chamber 66 become equal,
If the pressures in the pressure chambers 65 and 66 are equal, the spring 6 is weak.
9 contacts the close check valve portion 63. As a result, the pressure in the load pressure detection path 82 becomes equal to the load pressure,
The pump discharge pressure is controlled by the pump adjustment direction control valve 85 to a pressure higher than the pressure in the load pressure detection path 82 by a certain differential pressure (here, 20 kg / cm ² ). Since this pump discharge pressure is guided to the input port 44 via the check valve section 63, that is, the direction control valve 5
5 between the inlet pressure and the outlet pressure (= load pressure).
0 kg / cm ² ). Therefore, only when the opening area of the throttle between the inlet side and the outlet side changes with the stroke of the direction control valve 55, the actuator 8
The flow supplied to 8 is controlled. When the directional control valve 55 is stroked, the conduit 89 or 90 of the actuator 88 is connected to the second oil passage 53 for introducing load pressure, while the second oil passage 53 is connected to one pressure chamber 65 of the pressure reducing valve part 74.
The load pressure at the pressure reducing valve section 74 is
Since it is used only as the pilot pressure (set pressure of the pressure reducing valve), the pressure does not escape, that is,
When the directional control valve 55 is stroked, there is no spontaneous lowering of the actuator 88 due to the release of the load pressure.

The load pressure detecting path 82 is connected to the pressure reducing valve portion 7 of the pressure compensating valve 75 provided in the other directional control valve 55.
4 is connected to the other pressure chamber 66, but one pressure chamber 65 of the pressure reducing valve portion 74 is connected to the tank 86 by the neutral position A of the direction control valve 55, so that the load pressure is zero. Therefore, the pressure in the pressure chamber 66 is reduced by the pressure in the pressure chamber 66.
Urges the check valve 63 in the closing direction. on the other hand,
Since the pump discharge pressure is guided from the pump discharge path 81 to the pressure chamber a in the direction in which the check valve part 74 is opened, the differential pressure between the pump discharge pressure and the pressure in the load pressure detection path 82 (= 20 kg / cm ² ), the check valve portion 63 and the pressure reducing valve portion 74 are stroked in the opening direction of the check valve portion 63. If the stroke is slightly increased and the pressure at the input port 44 becomes the differential pressure (= 20 kg / cm ² ), The receipt is performed by the weak spring 69, and as a result, the pressure reducing valve section 74 does not stroke until the stroke end, and the hydraulic control on the direction control valve 55 side is not affected at all.

When the stroke of any of the direction control valves 55 is moved to the first pressure oil supply position B. When the total flow required for each actuator 88 is less than or equal to the maximum discharge flow of the hydraulic pump 20; Now, the direction control valves 55 are both stroked to the first pressure oil supply position B, and each input port 44, each conduit 89, and the first.
It is assumed that the second load pressure detection ports 45 and 46 are respectively connected. One of the pressure reducing valves 74 operates until the pressure in the pressure chamber 66 becomes equal to the pressure in the one pressure chamber 65, and the other pressure reducing valve 74 operates to reduce the pressure in the pressure chamber 66 to one of the pressure chambers 65. , Respectively, until they equal the internal pressure. Now, it is assumed that the load pressure of the left actuator 88 among the load pressures of the two actuators 88, 88 is larger. Assuming that the load pressure of the left actuator 88 is 100 (kg / c
m ² ), and the load pressure of the right actuator 88 is increased to 10 (k).
g / cm ² ). Since the load pressure detection path 82 is connected to the tank 86 via the throttle 91, the pressure in the load pressure detection path 82 is zero before the directional control valve stroke.
Accordingly, each pressure reducing valve portion 74 is provided with the first oil passage 53 for detecting the load pressure.
And the pump discharge pressure communicates with the pressure in the pressure sensing conduit 34. The right actuator 88 in which the pressure in the load pressure detection path 82 is on the low pressure side
When raised to a pressure in the conduit 90 (10kg / cm ^2), first pressure reducing valve 74 of the pressure compensating valve 75 of the right is closed. The pressure reducing valve portion 74 of the left pressure compensating valve 90 remains in the stroke, and the pressure in the load pressure detecting path 82 increases until it becomes equal to the pump discharge pressure (20 kg / cm ² ).
At this time, the pressure at the input port 44 of the direction control valve 55 of the left actuator 88 on the high pressure side is 100 (kg / c).
m ² ), the check valve portion 63 of the pressure compensating valve 75 is closed, and is separated from the pressure reducing valve portion 74. On the other hand, the pressure reducing valve portion 74 of the pressure compensating valve 75 urges the check valve portion 63 in the closing direction by a difference between the pressures in the two pressure chambers 65 and 66 (20−10 = 10 kg / cm ² ). On the other hand, the pressure in the pressure chamber a in the opening direction of the check valve portion 63 (pump discharge pressure)
Is 20 (kg / cm ² ), and as a result, the pressure of the input port 44 of the directional control valve 55 becomes 10 (kg / c 2).
After the check valve portion 63 is opened until m ² ), the receipt is performed by the weak spring 69. By the pump control directional control valve 85, only by a certain differential pressure (20 kg / cm ² )
The pump discharge pressure is controlled to a pressure higher than the pressure (20 kg / cm ² ) in the load pressure detection path 82 (40 kg / c).
m ² ). Also at this time, the pressure in the load pressure detection path 82 is 40 (kg / c) while the check valve portion 63 of the high-pressure side pressure compensating valve 75 is closed and the pressure reducing valve portion 74 is still stroked.
m ² ), while the pressure reducing valve portion 74 of the low pressure side pressure compensating valve 75 is checked by the pressure difference (= 30 kg / cm ² ) between the load pressure detecting path 82 and the first oil path 53 for introducing the load pressure. The valve portion 63 is biased in the closing direction, and as a result, the direction control valve 55
Of the input port 44 remains at 10 kg / cm ² . In this way, the pressure in the load pressure detection path 82 and the pump discharge pressure continue to rise, and eventually when the pump discharge pressure becomes equal to the load pressure (100 kg / cm ² ) of the high-pressure side actuator 88, the high-pressure side pressure compensation Pressure reducing valve section 63 of valve 75
The pressure in the two pressure chambers 65 and 66 is 100 kg
/ Cm ² , and is closed by the weak spring 69 and abuts against the check valve portion 63. At this time, the low pressure side pressure compensating valve 7
5 is provided with a pressure difference (100−10 = 90 kg / c) between the load pressure detection path 82 and the first oil path 53 for introducing the load pressure.
At m ² ), the check valve portion 63 is urged in the closing direction, and as a result, the pressure at the input port 44 of the directional control valve 55 on the low pressure side remains at 10 kg / cm ² . Again, the pump discharge pressure is set to 120 (kg) by the pump adjustment direction control valve 85.
/ Cm ² ). At this time, the pressure reducing valve portion 63 of the high-pressure side pressure compensating valve 75 is merely in contact with the check valve portion 63 by the weak spring 69, and the check valve portion 63
Due to the pressure difference between the two pressure chambers a and b, the check valve portion 63 is opened for the first time, and the pump discharge pressure (120 kg /
cm ² ) is led to the input port 44 of the directional control valve 55. On the other hand, the pressure reducing valve portion 74 of the low pressure side pressure compensating valve 75 is connected to the load pressure detecting path 82 and the first and second load pressure detecting ports 45 and 4.
6, the check valve 63 is continuously urged in the closing direction by the pressure difference (= 90 kg / cm ² ).
The pressure in the pressure chamber a in the opening direction is 120 (Kg / c
m ² ), the check valve section 63 and the pressure reducing valve section 74 are pressure-balanced in a state where the pressure at the input port 44 of the direction control valve 55 is 30 (Kg / cm ² ) (120-90). That is, the check valve section 63 and the pressure reducing valve section 74
Strokes slightly, and at the check valve portion 63,
It is in a state of being squeezed so as to be 120 kg / cm ² to 30 kg / cm ² . For the first time, this hydraulic control system is balanced and the input port 44 of the high-pressure side directional control valve 55 is
Is 120 kg / cm ² , and the low-pressure side directional control valve 55
Is 30 kg / cm ² , that is, the difference between the inlet pressure and the outlet pressure (load pressure) of the two directional control valves 55, 55 is both maintained at 20 kg / cm ² , The two directional control valves 55, 55
The flow rate supplied to the actuators 88, 88 can be controlled only by the stroke.

When the sum of the flow rates required for the actuators 88 is greater than the maximum discharge flow rate of the hydraulic pump 80; Now, the load pressure and required flow rate of the actuators 88, 88 are set to 100 kg / cm ² ,
501 / min, right actuator 88 is 10kg
/ Cm ² and 501 / min. When the maximum discharge flow rate of the hydraulic pump 80 is 1001 / min or more, as described above, the difference between the inlet pressure and the outlet pressure of the directional control valves 55, 55 is kept constant (= 20 kg / cm ² ). Thus, the flow rate can be controlled, and the flow rate can be distributed every 501 / min. Next, it is assumed that the maximum discharge amount of the hydraulic pump 80 becomes 701 / min. Two directional control valves 5
The inlet pressure of 5,55 is 120 kg / cm ² , 3 as described above.
Since the pressure is 0 kg / cm ² , the flow rate to the high-pressure side directional control valve 55 is reduced from 501 / min to 201 / min. The flow rate to the low pressure side directional control valve 55 remains at 501 / min. If the strokes (opening areas) of the two directional control valves 55 are not changed, the differential pressure between the inlet pressure and the outlet pressure of the high-pressure side directional control valve 55 is reduced by 20 k by the reduced flow rate.
g / cm ² . Now, the differential pressure is 14kg / c
m ² , ie, the inlet pressure is from 120 kg / cm ² to 1
Assume that the pressure has dropped to 14 (100 + 14) kg / cm ² .
At this time, the two pressure chambers 6 of the pressure reducing valve portion 74 of the pressure compensating valve 75
Since the pressures 5 and 66 remain at 100 kg / cm ² , the pressure-reducing valve portion 74 is only in contact with the check valve portion 63 by the weak spring 69, and the check valve portion 6
3. The pressure in the pressure chamber b in the closing direction is 120 kg / cm.
If the pressure is reduced from ² to 114 kg / cm ² , the pressure in the pressure chamber a in the opening direction of the check valve 63, that is, the pump discharge pressure is 120 kg / cm ² , while the check valve 63 is open (stroke end). To 114 kg / cm ²
To decrease. At this time (when the pump discharge flow rate is insufficient), the pump discharge pressure is not controlled by the pump adjusting direction control valve 85. On the other hand, the pressure reducing valve portion 7 of the pressure compensating valve 75 on the low pressure side
4, two pressure chambers 65 and 66 are 100 kg / cm ² ,
10 kg / cm ² , the differential pressure is 90 kg / cm ²
To continue to bias the check valve 63 in the closing direction. On the other hand, the pressure in the pressure chamber a in the opening direction of the check valve portion 63,
That is, since the pump discharge pressure has been reduced to 114 kg / cm ² , the check valve 63 and the pressure reducing valve are maintained in a state where the pressure in the pressure chamber b in the closing direction of the check valve 63 is reduced from 30 kg / cm ² to 24 kg / cm ^2. Section 74 is pressure balanced. Therefore, the differential pressure between the inlet pressure and the outlet pressure of the directional control valve 55 on the low pressure side is 20 kg / cm ² to 14 kg / cm ^2.
2 (24-10). Due to the decrease in the differential pressure of the directional control valve 55, the supply flow rate to the actuator 88 on the low pressure side decreases from 501 / min, and the supply flow rate to the actuator 88 on the high pressure side increases accordingly from 201 / min. That is, the differential pressure between the inlet pressure and the outlet pressure of the directional control valves 55 and 55 is equal, and the two actuators 8
The hydraulic control system is balanced in a state where the supply amounts to 8, 88 are both distributed at 351 / min.

When three or more actuators are loaded by one hydraulic pump 80. Even when there are three or more actuators, the same check valve portion 63 and pressure reducing valve portion 74 are provided between the directional control valve and the hydraulic pump.
The pressure compensating valve 75 provided with the pressure reducing valve is provided, and the pressure difference in the closing direction of each pressure reducing valve portion is merely communicated by the load pressure detecting path 82. Even when the number of actuators is three or more, the operation based on the above-described operation principle can be performed. Is achieved. Although the hydraulic pump 80 is a variable displacement type in the above embodiment, the hydraulic pump 80 may be a fixed displacement type. In this case, an unload valve may be provided in the pump discharge path 81 of the hydraulic pump 80.

[0016]

[Effects of the Invention] A plurality of valve blocks 30 are connected to the front and rear surfaces 40 and 4.
1 by overlapping and connecting each other, each valve block 30
The first and second pressure detection ports 100 and 101 of the
4, the high-pressure oil does not flow into the pressure detection port 100 or 101 on the low-pressure side because it communicates with the safety valve 105.
One safety valve in a directional control valve device with multiple directional control valves
In addition to reducing the number of safety valves and reducing costs, it is possible to install the sensor in a small space due to its compact size, and to set the maximum operating force of the actuator connected to a specific directional control valve to the safety valve set pressure. It can be made higher than the maximum working pressure of the actuator connected to the other directional control valve, and the maximum working pressure can be arbitrarily adjusted.

[Brief description of the drawings]

FIG. 1 is a sectional view of a conventional directional control valve.

FIG. 2 is a circuit diagram of a pressure oil supply device.

FIG. 3 is a perspective view of a valve block showing an embodiment of the present invention.

FIG. 4 is a cross-sectional view of a state where the main spool and the spool are incorporated in the valve block.

FIG. 5 is a cross-sectional view of a pressure detection port portion showing a connection state of a plurality of valve blocks.

FIG. 6 is a longitudinal sectional view of a pressure detection port portion showing a connection state of a plurality of valve blocks.

FIG. 7 is a perspective view showing a connection state of a plurality of valve blocks.

FIG. 8 is a hydraulic circuit diagram thereof.

[Explanation of symbols]

30 ... valve block, 31 ... spool hole, 34 ... first actuator port, 35 ... second actuator port,
37 ... check valve hole, 38 ... pressure reducing valve hole, 39 ... pump port, 42 ... first port, 43 ... second port, 44
... input port, 45 ... first load pressure detection port, 46 ... second load pressure detection port, 47 ... first tank port, 48 ...
Second tank port, 49: main spool, 53: recess, 5
6 Oil hole, 58 Oil hole, 60 Spool, 63 Check valve, 64 Spool, 65 First pressure chamber, 66 Second pressure chamber, 69 Spring, 74 Pressure reducing valve, 75 Pressure compensation valve, 80: Hydraulic pump, 81: Pump discharge path, 82:
Load pressure detection path, 100 ... first pressure detection port, 101 ...
Second pressure detection port, 102 communication recess, 103 ball, 104 through hole, 106 spring, 107 safety valve,
110: cover block, 111: spring force adjusting mechanism.

Claims (1)

(57) [Scope of request for utility model registration] 1. A directional control valve for slidably fitting a main spool 49 into a spool hole 31 of a valve block 30 to communicate and shut off an input port 44 with first and second actuator ports 34 and 35, The first and second pressure detection ports 10 communicating with the first and second actuator ports 34 and 35 in the valve block 30
0, 101 and the first and second pressure detection ports 1
Balls 103 and 00 open in communication recesses 102 formed in one joint surface of valve block 30 and block the flow of pressurized oil from communication recesses 102 to the pressure detection ports.
And a through-hole 104 is formed over the connecting surface of the communication concave portion 102 and the other connecting surface of the valve block 30, and the plurality of valve blocks 30 are connected to each other to form the first and second pressure detecting ports 100, 100.
101 communicates with the through hole 104, and the adjacent valve block 30
The ball 103 is inserted between the first and second pressure detection ports 10.
A spring 106 is provided for pressing against the first and second pressure detection ports 100 and 101, and a cover block 110 is provided on one of the joint surfaces of the valve block 30 located at the most end. A spring force adjusting mechanism 111 for adjusting the spring force of a spring 114 pressed against the valve 101 is provided.
A directional control valve device, wherein the directional control valve device is in communication with the directional control valve device.