JPH0246801B2 - SHOKOSHIRINDANOSEIGYOKAIROSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control circuit device for a lifting cylinder used in a scrap cutting machine, a bulky waste crusher, and other machines.

A conventional control circuit device of this kind, for example, as shown in FIG. , and by operating the switching valve d, the lifting cylinder a is moved up and down, and the rod side circuit b and the pump circuit e are connected via the switching valve g, and the switching valve g is switched. Generally, a differential pressure circuit is configured to circulate the pressure fluid from the rod side circuit b to the head side circuit c, and a switching valve h is provided as a pressure relief circuit for arbitrarily removing high pressure from the head side circuit c. shall be. However, if the lifting cylinder a is large, a switching valve d with a large diameter must be used, which causes a relatively large shock to the hydraulic system during switching, and it is also necessary to consolidate each switching valve into a small size. There are disadvantages that make it difficult to do so.

These inconveniences can be solved by using multiple logic valves with a two-way seat type valve configuration whose opening and closing operations are controlled by the pressure in the pressure chamber instead of the switching valve, but if the multiple logic valves have a cylinder It is difficult to control not only lifting and lowering but also differential pressure drive and pressure relief.

The object of the present invention is to solve the above-mentioned problems by controlling the lifting cylinder with a logic valve, and at the same time to use the logic valve to control the operating pressure drive and pressure release of the lifting cylinder. A logic valve having a structure of a two-way seat valve whose operation is controlled by the pressure of a pressure chamber, in which the head side circuit and the head side circuit are connected to each other by two connection circuits, and each connection circuit is connected to a pump circuit and a tank circuit, respectively. a connection circuit between the pump circuit and the rod side circuit, a connection circuit between the tank circuit and the head side circuit, a connection circuit between the pump circuit and the head side circuit, and the tank circuit. The pressure chambers of the first logic valves, which are interposed in the connection circuits between the pump circuit and the rod side circuit, are connected to the rod side by operating the pilot valve. A pilot circuit for selectively introducing circuit pressure, tank pressure, or pump circuit pressure is connected to the second pilot circuit, which is interposed in the connection circuit between the tank circuit and the head side circuit.
The check valve and flow control valve of the pressure relief control circuit selectively connects the head side circuit to the tank or pump circuit, in which the pressure chamber of the logic valve is sequentially provided with a throttle valve, a check valve, and a flow control valve. The middle part is connected, and the higher pressure of the pressure of the pump circuit and the head side circuit is applied to the pressure chamber of the third logic valve interposed in the connection circuit between the pump circuit and the rod side circuit. A pilot circuit to be selectively introduced is connected, and a pressure chamber of a fourth logic valve interposed in a connection circuit between the tank circuit and the rod-side circuit is connected to the pump circuit or tank via a relief valve. Consists of selectively connected pilot pressure circuits.

By adopting such a configuration, the first
If the pressure of the rod side circuit or tank pressure is introduced into the pressure chamber of the logic valve and the pressure relief control circuit is connected to the tank, the pressure fluid of the pump circuit will be transferred to the pressure chamber of the logic valve.
The fluid in the head side circuit flows into the rod side circuit through the logic valve, and the fluid in the head side circuit flows out into the tank circuit through the second logic valve, and the lifting cylinder can be operated upward, and at this time, the high pressure in the head side circuit is increased. The fluid is gradually discharged by the throttle valve and flow control valve of the pressure relief control circuit, and when the pressure in the head side circuit decreases, the second logic valve opens to rapidly discharge the pressure fluid. The lifting cylinder can be raised without impact.

In addition, when the pressure of the pump circuit is introduced into the pressure chamber of the first logic valve by operating the pilot valve, and the pressure of the head side circuit is introduced into the pressure chamber of the third logic valve, the pressure becomes higher than the pressure of the pump circuit. Pressure fluid from the rod side circuit can be flowed into the head side circuit via the connection circuit and the third logic valve, and differential drive for driving the lifting cylinder downward can be performed without requiring a large flow rate from the pump circuit.

Furthermore, if the pressure of the head side circuit is introduced into the pressure chamber of the third logic valve, the pressure chamber of the fourth logic valve is connected to the tank, and each pressure chamber of the first and second logic valves is connected to the pump circuit. , counterbalance control can be performed to lower the lift cylinder while controlling its back pressure.

An example of the device of the present invention will be explained with reference to FIG. 2, in which reference numeral 1 is an elevating cylinder, 2 is a rod side circuit of the cylinder 1, 3 is a head side circuit thereof, and 4 and 5 are both circuits. 2 and 3 are shown, and each circuit 2 and 3 is connected to a pump circuit 6 via the connection circuit 4 and to a tank circuit 7 via the connection circuit 5.

8, 12, 21, and 22 are two-way seat valves whose operation is controlled by the pressure in the pressure chamber.
The first logic valve 8 is interposed in the connection circuit 4 between the pump circuit 6 and the rod side circuit 2, and the second logic valve 12 is interposed in the connection circuit 4 between the pump circuit 6 and the rod side circuit 2.
is interposed in the connection circuit 5 between the tank circuit 7 and the head side circuit 3, and the third logic valve 21 is interposed in the connection circuit 4 between the pump circuit 6 and the head side circuit 3. The fourth logic valve 22 is interposed in the connection circuit 5 between the tank circuit 7 and the rod side circuit 2.

A pilot circuit 11 is connected to the pressure chamber 8a of the first logic valve 8, which communicates with the pump circuit 6 via the shuttle valve 10 or the connection circuit 4 by switching the pilot valve 9, in order to control its opening and closing.
When the pilot valve 9 is in the position 9a, the pressure of the pump circuit 6 is introduced into the pressure chamber 8a, and when the pilot valve 9 is in the position 9b, either the rod side circuit 2 or the head side circuit 3 compared with the shuttle valve 10 is introduced. One pressure or tank pressure was introduced into the pressure chamber 8a. As the pressure in the head side circuit 3 or the tank pressure led to the shuttle valve 10, the pressure selected in the pressure relief control circuit 13 by operating a pilot switching valve 18, which will be described later, is used.

In the pressure chamber 12a of the second logic valve 12, a throttle valve 15, a check valve 16, a flow control valve 17, and a small pilot switching valve 18 are sequentially interposed from the head side circuit 3 so as to be connected to the tank 14. The check valve 16 and the flow control valve 1 of the pressure relief control circuit 13 provided
The pressure was introduced from between 7 and 7. As a result, when the head side circuit 3 is connected to the tank 14 by operating the pilot switching valve 18, the pressure in the pressure chamber 12a of the second logic valve 12 changes from the pressure in the throttle valve 15.
Since the pressure decreases slowly without causing a sudden pressure drop due to the flow control valve 17 and the flow rate control valve 17, the second logic valve 12 opens slowly when the pressure in the head side circuit 3 is high, and opens quickly when the pressure becomes low. Therefore, the confinement pressure of the head side circuit 3 can be discharged to the tank without impact. A pressure introduction circuit 19 is connected to the pilot switching valve 18 to introduce the pressure of the pump circuit 6.
When the pilot switching valve 18 is switched, the pressure of the pump circuit 6 acts on the pressure chamber 12a of the second logic valve 12 via the check valve 20 attached to the flow rate control valve 17, and the second logic valve 12 cuts off the communication between the head side circuit 3 and the tank circuit 7.

In the illustrated example, the pilot circuit 11 of the first logic valve 8 is connected to the shuttle valve 10 as described above.
Since the pressure relief control circuit 13 is connected to the pressure relief control circuit 13 via the pressure relief control circuit 13, a pressure equal to the pressure acting on the pressure chamber 12a of the second logic valve 12 is simultaneously introduced into the shuttle valve 10.

The pressure chamber 21a of the third logic valve 21 is connected to a pilot circuit 31 which introduces the highest pressure of the pressure of the head side circuit 3, the pump circuit 6, or the tank 14 through the shuttle valve 23. The pressure in the tank 14 is introduced from a pilot pressure circuit 26 connected to the pilot switching valve 18 through a throttle check valve consisting of a flow control valve 24 and a check valve 25.

A pilot pressure circuit 26 selectively connected to the pump circuit 6 or tank 14 via a relief valve 27 is connected to the pressure chamber 22a of the fourth logic valve 22, and the pressure chamber 22a is connected to a throttle valve 28. It was connected to the rod side circuit 2 via. The pilot pressure circuit 26 is connected to the pilot switching valve 1.
8, it is connected to the tank 14 or the pump circuit 6, and the pilot pressure circuit 26 is connected to the tank 14.
When the pressure chamber 22a of the fourth logic valve 22 is connected, the pressure in the pressure chamber 22a of the fourth logic valve 22 is controlled by the relief valve 27. The lowering of the lifting cylinder 1 can be controlled by performing control to discharge the fluid from the lifting cylinder 1 to the tank circuit 7 while generating .

29 is a safety valve of the rod side circuit 2, and 30 is a group of switches for instructing the pilot valve 9 and the pilot switching valve 18 to operate.

To explain its operation, when raising the lifting cylinder 1, the pilot valve 9 is left in the illustrated position 9b and the pilot switching valve 18 is first operated to move it to the position 18a. As a result, the pressure release control circuit 13 is connected to the tank 14, and the pressure of the pilot circuit 11 acting on the pressure chamber 8a of the first logic valve 8 via the shuttle valve 10 is connected to the tank 14.
or the pressure in the rod side circuit 2, the pressure fluid in the pump circuit 6 is allowed to push open the first logic valve 8 and flow into the rod side circuit 2, and the pressure in the head side circuit 3 is allowed to push open the second logic valve 12 and flow out into the tank circuit 7, thus causing the lift cylinder 1
The lifting operation is performed by the inflow of fluid into the chamber on the rod side and the discharge of fluid from the chamber on the head side. In this case, the pressure fluid in the head side circuit 3 is
and a pressure relief control circuit 1 with a flow control valve 17 interposed therebetween.
3, when the pressure is high, it is gradually discharged, and when the pressure becomes low, the second logic valve 12 opens as described above and rapidly discharges it, so that the pressure in the head side circuit 3 can be reduced without causing any shock. Discharge and lift cylinder 1
can perform the ascent.

When lowering the lifting cylinder 1, the pilot valve 9 is switched to position 9a and the pilot switching valve 18 is switched to position 18b. As a result, the pressure chamber 21a of the third logic valve 21 reaches the pressure of the tank 14 or the pressure of the normally low pressure head side circuit 3, so the fluid of the pump circuit 6 pushes the valve body of the third logic valve 21 open. Head side circuit 3
, and the lifting cylinder 1 descends while expelling fluid from the chamber on its rod side.
In this case, the first logic valve 8 operates as follows to circulate the flow rate from the rod side circuit 2 to the head side circuit 3 without consuming much of the flow rate of the pump connected to the pump circuit 6. The pump power can be saved by performing differential pressure driving to lower the elevating cylinder 1. That is, the first logic valve 8
The pressure of the pump circuit 6 (pump discharge pressure) is supplied to the first pressure chamber 8a via the pilot circuit 11.
The spring of the logic valve 8 acts in a direction to close the valve body, and the pressure of the pump circuit 6 acts on a part of the front surface of the valve body of the first logic valve 8 via the connection circuit 4. In this state, the first logic valve 8 does not open, but when the pressure in the rod-side circuit 2 that acts on other parts of the valve body increases, the valve body moves in the opening direction. The first logic valve 8 becomes open. Therefore, fluid with a pressure higher than the pressure in the pump circuit 6 flows from the rod side circuit 2 into the head side circuit 3 via the connection circuit 4 and the third logic valve 21, and a large amount of the flow rate from the pump circuit 6 flows into the head side circuit 3. The lifting cylinder 1 can be driven downward without the need for a.

When carrying out counterbalance control in which the back pressure of the lifting cylinder 1 is controlled and lowered, the pilot valve 9 is set to position 9b, and the pilot switching valve 18 is set to position 18b. Thus, the pressure chamber 21a of the third logic valve 21 is connected to the tank 14 via the shuttle valve 23 and the pilot pressure circuit 26, and the pressure chamber 22a of the fourth logic valve 22 is connected to the relief valve 27 and the pilot pressure circuit. 26 to the tank 14, and each pressure chamber 8 of the first and second logic valves 8, 12.
a, 12a are connected to the pump circuit 6 via a pressure relief control circuit 13 and a pressure introduction circuit 19. Therefore, the first and second logic valves 8 and 12 are closed, and the pressure fluid from the pump circuit 6 is transferred to the third logic valve 21.
The fluid in the rod side circuit 2 pushes open the fourth logic valve 22 and flows into the tank circuit 7, and the lifting cylinder 1 descends. In this case, the pressure chamber 22 of the fourth logic valve 22
The pressure of a is controlled by the relief valve 27 provided in the pilot pressure circuit 26 to the set pressure of the relief valve 27, and therefore the pressure of the fourth logic valve 2
2, the valve will not open unless the pressure in the rod side circuit 2 reaches a pressure that generates a force that overcomes the force due to the pressure in the pressure chamber 22a, and the lifting cylinder will not open while the rod side circuit 2 retains pressure. It is possible to carry out counterbalance control to lower the value of 1.

In this way, according to the present invention, four logic valves, first to fourth, are interposed in the two connection circuits that connect the rod side circuit and the head side circuit of the lifting cylinder, and the pump circuit and the In the pressure chamber of the first logic valve interposed between the rod side circuit,
A second logic interposed between the tank circuit and the head circuit is connected to a pilot circuit that selectively introduces the pressure of the rod side circuit or the tank pressure or the pressure of the pump circuit by operating a pilot valve. An intermediate between the check valve and the flow control valve of a pressure relief control circuit that selectively connects the head side circuit to the tank or pump circuit, in which the pressure chamber of the valve is sequentially provided with a throttle valve, a check valve, and a flow control valve. and selecting the higher pressure between the pressures of the pump circuit and the head side circuit into the pressure chamber of the third logic valve interposed in the connection circuit between the pump circuit and the head side circuit. Since the pilot circuit that is introduced automatically is connected, opening the first and second logic valves allows the lifting cylinder to rise without causing a shock to the hydraulic circuit, and opening the first and third logic valves. The lift cylinder is driven downward by differential pressure, and the pump circuit is also connected to the pressure chamber of the fourth logic valve interposed in the connection circuit between the tank circuit and the rod side circuit via the relief valve. Alternatively, since a pilot pressure circuit is selectively connected to the tank, the first and third logic valves can be opened to lower the lifting cylinder while controlling the counterbalance.
The four logic valves not only raise and lower the lifting cylinder, but also perform pressure relief control, differential drive, and counterbalance control, which is convenient.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a conventional circuit device, and FIG. 2 is a diagram of an example of a control circuit device of the present invention. 1... Lifting cylinder, 2... Rod side circuit, 3
...Head side circuit, 4, 5...Connection circuit, 6...
Pump circuit, 7... Tank circuit, 8... First logic valve, 8a... Pressure chamber, 9... Pilot valve,
11... Pilot circuit, 12... Second logic valve, 12a... Pressure chamber, 13... Pressure relief control circuit, 14... Tank, 15... Throttle valve, 17...
Flow rate control valve, 21...Third logic valve, 21a...
...Pressure chamber, 22...Fourth logic valve, 22a...
Pressure chamber, 26...Pilot pressure circuit, 27...
Relief valve, 31...Pilot circuit.

Claims (1)

[Claims] 1 A two-way seat type in which the rod side circuit and head side circuit of the lifting cylinder are connected to each other by two connection circuits, and each connection circuit is connected to a pump circuit and a tank circuit, respectively, and the operation is controlled by the pressure in the pressure chamber. A logic valve having a valve configuration is used in a connection circuit between the pump circuit and the rod side circuit, a connection circuit between the tank circuit and the head side circuit, and a connection circuit between the pump circuit and the head side circuit. A pilot valve is inserted into the pressure chamber of the first logic valve which is interposed in the connection circuit and the connection circuit between the tank circuit and the rod side circuit, and is interposed in the connection circuit between the pump circuit and the rod side circuit. Connecting a pilot circuit that selectively introduces the pressure of the rod side circuit, the tank pressure, or the pressure of the pump circuit by operating a valve,
A pressure chamber of a second logic valve interposed in a connection circuit between the tank circuit and the head side circuit is provided with a throttle valve, a check valve, and a flow rate control valve in sequence, and the tank or pump is connected to the head side circuit. A pressure chamber of a third logic valve that connects the intermediate portion of the check valve and the flow control valve of the pressure relief control circuit selectively connected to the circuit, and is interposed in the connection circuit between the pump circuit and the head side circuit. A pilot circuit that selectively introduces the higher pressure of the pump circuit and the head side circuit is connected to the pilot circuit, and is further interposed in a connecting circuit between the tank circuit and the rod side circuit. A control circuit device for a lifting cylinder comprising a pilot pressure circuit selectively connected to the pump circuit or tank via a relief valve and connected to the pressure chamber of the fourth logic valve.