JPS6015030Y2 - Hydraulic directional valve with flow diversion mechanism - Google Patents

Description

[Detailed description of the invention] This invention is a circuit that uses three pumps to operate a large number of actuators, and the pressure oil discharged from one of the pumps is diverted to the other two pumps. belong 2
In a device that supplies two circuits, it is related to a compound valve that selectively supplies pressure oil discharged from one pump to both circuits equally or only to one circuit depending on the load pressure of the circuit. It is.

Conventionally, many hydraulically driven construction machines and the like have used two pumps and multiple directional valves to operate a large number of hydraulic actuators.

For this reason, it is difficult to set the operating speed of each hydraulic actuator to an optimal value, resulting in an average value.

The present invention is applied to a circuit in which one pump is added to the conventional circuit using two pumps and a multiple directional valve.
You can divide the discharge oil of the added pump into equal parts and supply it to the discharge passages of the other two pumps, or combine the divided oil and supply it to the discharge passage of the other pump. The additional pump discharge oil can be rationally distributed and the operating speed of each hydraulic actuator can be set to the optimum value by preventing the backflow of oil, etc. A directional control valve that is inexpensive and can be installed in machines that require compactness, such as construction machinery, by integrating components such as switching valves and check valves into one piece rather than providing them separately, which takes up less space. The purpose is to provide the following.

In order to achieve the above-mentioned purpose, the hydraulic directional control valve having a flow dividing mechanism according to the present invention is slidably provided in a sealed body 17 as shown in the second figure, and has springs 22 at both ends.
．． a cylindrical outer spool 20 preloaded by 23;
The inner spool 21 is slidably provided within the outer spool 20 and the primary port A is provided in the center of the body 17.
, two secondary ports B and C provided on the right and left parts of the body 17, and a secondary port A formed on the right and left symmetrical parts of the inner periphery of the body 17 and the outer periphery of the outer spool 20, respectively. and two secondary ports) B and C for opening and closing by means of two lands 45 and 44 in the center of the outer spool 20.
A first hydraulic pressure is formed between the groups 73, 42 and 74, 43, the two caps 35.36 at both ends of the outer spool 20, and the two bushings 39.40 fitted therein. chamber 64.65 and two bushes 39
．． 40 and two first hydraulic chambers 64, 65 and 2.
two narrow first passages 66.67 that communicate with the secondary ports B and C; two second passages 68.69 provided in the two caps 35.36; Two check valves 75. inserted into the two second passages 68.69.
76, a third passage 41 provided in the center of the outer spool 20, and a third passage 41 formed between the outer and inner spools 20, 21, and a third passage 41 provided in the center of the outer spool 20, Gap 7 on the right and left side communicating with the passage 46, 47 of 4
0.71, and two holes formed at both the right and left ends of the inner spool 21 and communicating with the left and right gaps 71.70 via two sixth passages 60.61 inside the inner spool 21. with the second hydraulic chamber 77,78 of the pilot directional valve 1
1 (see FIG. 1), and two fourth passages 46 and 47 provided on the right and left parts of the outer spool 20 constituting this pilot directional switching valve 11; 46
．． The lands 51.52 at both ends of the inner spool 21, which adjust the opening area of the inner spool 21, form the variable throttle diverter valve 10 in FIG. In the two fifth passages 62 and 63 communicating between 47 and the two secondary ports B and C, two reverse flow channels are formed in the forward direction toward the two secondary ports B and C, respectively. It is constructed by inserting prevention valves 26 and 27 (corresponding to 14 and 13 in FIG. 1).

The switching valve of the present invention having such a configuration has its primary side port A connected to the additional pump 3 as shown in the first figure, and its two secondary side ports B and C connected to the two pumps 2 and 3, respectively. This is used by communicating with the first discharge circuit.

When the pressure difference between the discharge circuits of pumps 1 and 2 is small, the outer spool 20 maintains the neutral position, so the oil discharged from the pump 3 is equally divided to the left and right from port A, and flows to the outer and inner spools 20. .21, through the divider valve 10 (see FIG. 1) by the fourth passage 46.47, and then through the non-return valve 27.26 (13.14 in FIG. 1) to the port. It is supplied from C9B to the discharge circuits of pumps 1 and 2, respectively.

When the pressure difference between the discharge circuits of pumps 1 and 2 increases, the outer spool 20 will be moved by the higher pump discharge pressure, in other words, if the discharge pressure of pump 1 is higher, it will move to the right, and vice versa. If so, the oil discharged from pump 3 passes through group 74 or 73 from pump A to check valve 2.
7 or 26, and is supplied only to the discharge circuit of pump 1 or 2, which has a higher circuit pressure than port C or B, and joins the discharge oil of pump 1 or 2.

Further, when the discharge pressure of the pump 3 becomes high pressure, the unload valve 9 operates to unload the discharge oil of the pump 3, and the operation of each hydraulic actuator is controlled by the flow rate of only the pumps 1 and 2. The engine 4 is operated so as not to be overloaded.

First, a basic hydraulic circuit to which the present invention is applied will be explained with reference to FIG.

In FIG. 1, 1 to 3 are 3 driven by an engine 4.
pumps.

Pumps 1 and 2 have the same capacity, and each pump 1 and 2
Main relief valves 5, 6 and multiple directional control valves 7, 8, each having a high set pressure, are connected to each other.

The multiple directional control valves 7 and 8 are equipped with two travel hydraulic motors 15,
A number of hydraulic actuators including 16 are connected.

The pump 3 includes an unload valve 9 with a lower set pressure than the main relief valves 5 and 6, a flow divider valve 10 that always divides the oil amount into equal parts even if the load pressure on the secondary side fluctuates, and the pressure on the secondary side. is used as a signal to change the position of the spool 12 to control the discharge direction of the pressure oil.The pilot direction switching valve 11 is connected in this order, and the two secondary pipes exiting from the pilot direction switching valve 11 are connected in this order. A check valve 13, 14 is inserted in each of the pumps 1 and 2 to supply pressure oil from the pump 3 to the pump 1 circuit and the pump 2 circuit.

A signal on the secondary side of the pilot directional control valve 11 is taken in from the pump 1 circuit side and the pump 2 circuit side through the check valves 13 and 14, respectively.

When the difference between the circuit pressure of the pump 1 and the circuit pressure of the pump 2 is small, the spool 12 is in the neutral position, and the pilot directional switching valve 11 separates the hydraulic oil from the downstream side to each pump on the secondary side. When the difference between the circuit pressure of pump 1 and the circuit pressure of pump 2 increases, the spool 12 moves and has the function of allowing the pressure oil to join and flow only into the pump circuit with the higher circuit pressure. .

Furthermore, when the circuit pressure becomes high, the unload valve 9 operates to unload the discharge amount of the pump 3, and the operation of each hydraulic actuator is controlled by the flow rate of only the pumps 1 and 2, so that the engine 4 is not overloaded. It also has the ability to operate like this.

Note that conventionally, two pumps 1 and 2 driven by an engine 4, main relief valves 5 and 6, and multiple directional control valves 7 and 8 are used to configure a circuit that operates a large number of hydraulic actuators. There is.

The present invention is based on the main components of this circuit, such as a diverter valve 10, a pilot directional control valve 11, and a check valve 13.
．． 14 has an integral structure, and one embodiment thereof will be described next with reference to FIG.

This directional control valve is applied to a circuit in which one pump 3 is added to a circuit that operates a large number of hydraulic actuators using two pumps 1, 2 and multiple directional control valves 7, 8, and is sealed. Inside the body 17, there are springs 22 and 23 at both ends.
A cylindrical outer spool 20 which is preloaded by a cylindrical outer spool 20 is slidably provided, and an inner spool 21 is installed inside this outer spool 20.
is provided on the slidable part 1, and the primary side port A and the other two pumps 2, which communicate with the added pump 3, are provided in the central part of the body 17 and in the right and left parts symmetrical to this central part, respectively.
Two secondary ports B and C are provided which communicate with one discharge circuit, and two secondary ports in the center of the outer spool 20 are connected between the secondary port A and the two secondary ports B and C. Land 45.4
4 groups of 2 each for opening and closing 73, 42
and 74 and 43 are respectively formed on the right and left symmetrical parts of the inner periphery of the body 17 and the outer periphery of the outer spool 20.
0' two caps 35.36 on both ends and two bushings 39.40 fitted into these two caps 35.36.
two thin first hydraulic chambers 64 and 65 are formed between the passages 66.67 and two second passages 68.69 are provided in the two bushings 39.40 and the two caps 35.36 respectively;
Two check valves 75.76 are inserted into two narrow second passages 68.69 provided in the two caps 35.36 in a forward direction toward the two first hydraulic chambers 64.65. The opening area is adjusted by the third passage 41 and the lands 51 and 52 at both ends of the inner spool 21 at the center of the outer spool 20 and at the right and left parts symmetrical to this center. Two fourth passages 46,47 are provided, and the right and left fourth passages 46,47 and two secondary ports B,
Two non-return valves 27, 26 are inserted in the two fifth passages 62, 63 that communicate with the , outer and inner spools 20, 21, the central third of the outer spool 20
Right and left gaps 70.71 are formed to communicate the passage 41 with the right and left fourth passages 46.47, and the left and right gaps 71 are formed at both right and left ends of the inner spool 21, respectively. ．．
The two sixth passages 60 inside the inner spool 21 at 70
．． two second hydraulic chambers 77, 78 communicating via 61;
It becomes formed.

In addition, 18.19 is a cover to seal the body 17,
37 and 38 are secondary side ports B, respectively.

Pilot passages 72 are formed on the inner periphery of the center of the body 17, and pilot passages 48 and 55 are formed on the inner periphery of the center of the outer spool 20 and the outer periphery of the inner spool 21, respectively. the group formed,
49.56 and 50°57 are the outer spools 20 respectively
The groups 53 and 54 are formed on the right and left symmetrical parts of the inner periphery of the inner spool 21 and the outer periphery of the inner spool 21, respectively.
This is a land of the inner spool 20 for forming a gap 70, 71 between the inner circumference of the inner spool 20 and the inner periphery of the inner spool 20.

58 and 59 are the gap 70 and 71 and the second hydraulic chamber 7, respectively.
This group is formed in the land 53.degree. 54 of the inner spool 21 and communicates with the opening on the gap side of the sixth passage 61.60 which communicates with the land 53.degree.

Reference numerals 33 and 34 indicate O-rings inserted between both ends of the outer spool 20 and the caps 35 and 36, and 24 and 25 indicate second hydraulic chambers 77 at both ends of the inner spool 21, respectively.
This is a spring with a weak spring force inserted in the inner spool 78 to stabilize the inner spool 21 in the center.

28 and 29 are the springs of the check valves 26 and 27, respectively, and 31 and 32 are the springs of the check valves 75 and 76, respectively.

Also, a fourth passage 46.4 with group 49.50
7 and lands 51 and 52 constitute the variable throttle diverter valve 10 in Fig. 1, the check valves 26 and 27 correspond to 14 and 13 in Fig. 1, and the others are pilot directional control valves. It consists of 11.

Note that the preload force of the springs 22 and 23 determines when the outer spool 20 moves when the differential pressure between the circuit pressure of pump 1 and the circuit pressure of pump 2 reaches a certain value, and it depends on the applied system. different.

Since the present invention has the above-mentioned configuration, the pressure of (Po)B (
The circuit pressure of the pump 2 is led from the pilot passage 37 through the first passage 66, and from the passage 37 through the second passage 68 and the check valve 75 to the first hydraulic chamber 64, and the pressure at port C is (circuit pressure of pump 1) passes through the first passage 67 from the pilot passage 38, and from the passage 38 through the second passage 67.
The first hydraulic chamber 65 passes through the passage 69 and the check valve 76.
be guided by.

At this time, if the force due to the differential pressure between the pressure at port B and the pressure at port C is smaller than the force of the preloading spring 22.23, the outer spool 20 does not move, and the pressure oil flowing from port A (pump 3) is the outer spool 2
0 and the inner spools 21 are made completely symmetrical, so that the flow passes through the third passage 41 and is divided equally through the group 55 of the inner spools 21, with gaps 70, 71
, groups 56, 57, groups 49, 50 and 4th
It passes through passages 46 and 47, passes through check valves 26 and 27, passes through fifth passages 62 and 63, and is supplied to the pump 2 and pump 1 circuits from port B1 and port C.

At this time, if the pressure in port B is slightly higher than the pressure in port C, the flow rate flowing through the gap 70 will be small and the flow rate flowing through the gap 71 will be large. Group 5 with high pressure
8. It is received by the sixth passage 61 and guided to the second hydraulic chamber 78 on the left side of the inner spool 21, and the pressure decrease due to the increase in flow velocity in the gap 71 and the low pressure at port C are transferred to the group 59.
, is received by the sixth passage 60 and guided to the second hydraulic chamber 77 on the right side of the inner spool 21, and the differential pressure between them moves the inner spool 21 to the right side, and the group 50 of the outer spool 20 and the inner spool 21 are separated. The opening area formed by the land 52 is reduced, and the group 49 and the land 51 are
By increasing the opening area formed by
The pressure in the gap 71 is increased and the pressure in the gap 70 is decreased to set the inner spool 21 in the appropriate position and equalize the flow rate through the waist gap 70 and the flow rate through the gap 71.

If the pressure at port C is high, it is adjusted in the same way.

As a result, even if the circuit pressure connected to ports B and C fluctuates, the flow rate flowing into port A is equally divided and sent out from ports B and C.

At this time, even if the pressure in ports B and C increases and the unload valve 9 is activated, the discharge oil from the pumps 1 and 2 will not return to the tank due to the action of the check valves 26 and 27.

If the pressure at port B is high and the pressure at port C is low and the differential pressure is greater than the force of the preloading spring 23, the outer spool 20 moves to the left, and the group 42 of the outer spool 20 and the group 73 of the body 17 and group 7
2, and the land 44 closes the group 74.

As a result, the total pressure oil flowing into port A is group 72,
It passes through the groups 42 and 73, the non-return valve 26, and the fifth passage 62, and flows out from port B, but does not flow out from port C.

Even if the pressure in port C is high and the pressure in port B is low and the differential pressure between them is greater than the preloading spring 22, all the pressure oil that has flowed into port A will flow out from port C, and from port B. It doesn't flow out.

Furthermore, when a first passage 66.67 communicating with the first hydraulic chamber 64.65 and a second passage 68.69 having a check valve 75.76 are provided as in the present invention, the outer spool 20 moves. In this case, the oil trapped in the first hydraulic chambers 64 and 65 tries to be discharged, but the outlet
passages 66 and 67 of the outer spool 20
movement speed will be limited.

As is clear from the above explanation, the present invention provides the following effects.

(1) By applying the switching valve of the present invention to a circuit in which one pump 3 is added to a circuit that operates multiple hydraulic actuators using two pumps 1, 2 and multiple directional switching valves 7, 8. Depending on the operating state of the multiple directional valve 7.8, the discharge oil of the added pump 3 can be automatically supplied to the circuit of the first pump 1 or the circuit of the second pump 2, respectively, or separately. The operating speed of each actuator can be automatically set to the optimum value.

(2) Hydraulic pressure that has the functions of oil supply and backflow prevention through the switching valve of the present invention, i.e., dividing and merging, with an integrated structure without separately installing components such as a diverting valve, a pilot hydraulic directional switching valve, and two check valves. Since a directional switching valve can be realized and can be made very compact, it can easily fit into a small space such as a construction machine, and cost reduction can also be achieved.

(3) Double structure of inner and outer spools and waist outer spool 2
Since the rate of change in flow rate can be reduced by moving 0, there is less shock to the actuators and the driver can operate stably.

(4) Gap 7 formed between the outer and inner spools 20 and 21
0.71, the second hydraulic chambers 78.77 at both ends of the inner spool 21 communicating with this gap 70.71, the fourth passage 46.47 of the outer spool 20 and the lands 51.52 of the inner spool 21. The variable throttle allows the flow to be divided into two circuits in equal amounts at all times regardless of external load pressure.

(5) Since pressure oil suitable for the hydraulic actuator can be supplied, the output of the drive source 4 can be small as a result, the amount of fuel used can be reduced, and the structure of the hydraulic equipment can be made relatively simple.

[Brief explanation of the drawing]

FIG. 1 is a piping diagram showing an example of a circuit to which the present invention is applied, and FIG. 2 is a sectional view showing an embodiment of the present invention. 17...Body, 20...Outer spool, 21...Inner spool, 22.23...
...Spring, 26.27...Return prevention valve, 35.36...Cap, 39.40...
... Bush, 41 ... Third passage, 46.
47...4th passage, 60, 61...
6th passage, 64.65... 1st hydraulic chamber, 6
6.67...First passage, 68.69...
...Second passage, 70.71...Flow path (gap)
, 73.74...Aisle (group), 75.7
6...Check valve, 77.78...Second hydraulic chamber, A...-Next port, B, C...
...Secondary side port, 42.43...Group, 44.45...Land, 62.63...
...The fifth passage.

Claims (1)

[Claims for Utility Model Registration] Direction applied to a circuit in which one pump 3 is added to a circuit that operates multiple hydraulic actuators using two pumps 1 and 2 and multiple directional valves 7 and 8 A switching valve,
A cylindrical outer spool 20 which is slidably provided in a sealed body 17 and whose both ends are preloaded by springs 22, 23, an inner spool 21 which is slidably provided in this outer spool 20, and a body 17. A primary side port A is provided in the center of the body 17 and connects to the added pump 3, and two secondary ports are provided on the right and left sides of the body 17 and communicate with the discharge circuits of the other two pumps 2 and 1. Ports B and C are formed on the right and left symmetrical parts of the inner periphery of the body 17 and the outer periphery of the outer spool 20;
between the two lands 45 at the center of the outer spool 20.
．． two groups 73 each for opening and closing by 44;
42 and 74.43, and 2 at both ends of the outer spool 20.
A first hydraulic chamber 64.65 is formed between each cap 35.36 and two bushings 39.40 fitted thereto, and a first hydraulic chamber 64.65 is provided in the two bushings 39.40,
Two first hydraulic chambers 64,65 and two secondary ports B
, two narrow first passages 66, 67 communicating with C;
Two check valves 75°76 inserted into two second passages 68,69 provided in two caps 35,36
and a third passage 41 provided in the center of the outer spool 20, and between the outer and inner spools 20.21,
The right and left gaps 70. communicate this third passage 41 with the right and left fourth passages 46,47 of the outer spool 20.
71 and is formed on both the right and left ends of the inner spool, and the left,
The pilot directional control valve 11 is constituted by two second hydraulic chambers 77,78 communicating with the right-hand gap 71,70 via two sixth passages 60,61 inside the inner spool 21, Two fourth passages 46 provided on the right and left sides of the outer spool 20 that constitute this pilot direction switching valve 11
．． 47 and the lands 51.52 at both ends of the inner spool 21 that adjust the opening area of the fourth passage 46.47 constitute a diverter valve 10 with a variable throttle. Two fifth passages 62.6 communicate the passages 46.47 of No. 4 with the two secondary ports B and C.
3, each with two secondary ports B. A hydraulic directional switching valve having a flow dividing mechanism in which two check valves 26 and 27 are inserted in the forward direction toward C.