JP2504661B2 - Speed-up hydraulic circuit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed increasing hydraulic circuit.

[0002]

2. Description of the Related Art Conventionally, in an attempt to increase the working speed of a working piston in a hydraulic circuit of this type, a manual switching valve guides the return oil from the working cylinder into a supply duct to the working cylinder to form a speed increasing circuit. Alternatively, a method of forming a speed-up circuit by introducing return oil from the work cylinder into a supply duct to the work cylinder depending on the magnitude of the hydraulic pressure on the work cylinder side (pressure control) has been adopted. However, the operation by the manual switching valve is complicated and the switching timing may be lost.On the other hand, in the case of the pressure control, the control circuit for increasing the speed becomes complicated and expensive, and its function lacks stability. The disadvantage is that a completely automatic circuit cannot be constructed because it causes a malfunction.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to automatically increase or decrease the speed of a working cylinder according to the size of a load without using a manual switching valve or using a complicated pressure control circuit. SUMMARY OF THE INVENTION It is an object of the present invention to propose a speed-up hydraulic circuit for efficiently hydraulically driving a work cylinder and automatically and automatically preventing the work cylinder from operating, which may cause a failure of the work cylinder.

[0004]

The object of the present invention is solved by the constitutions of claims 1 and 2.

[0005]

[Operation] When the load is small, a check valve that allows the piston rod side of the working cylinder and the opposite side of the piston rod to be opened is opened to replenish pressure oil on the piston rod side to the opposite side of the piston rod to increase the flow rate of the working cylinder. When the operating speed of the piston device is increased and the load is increased, the above-mentioned speed-up hydraulic circuit is closed to restore the normal operating speed, and in this way, the working cylinder is automatically adjusted according to the size of the load. The operating speed of the piston of the piston device is increased or decreased to achieve efficient operation of the work cylinder piston device.

[0006]

1 and 2, the hydraulic pump 1 has its suction duct connected to an oil tank 2,
Is connected to the 3-position 3-connection switching valve 3 on the output side, and the 3-position 3-connection switching valve 3 is in the position shown in FIG. 1 during normal operation. The hydraulic circuit according to the present invention is installed in the block 4, and includes a first pressure balancing type switching valve 5, a first check valve 6,
It comprises a second pressure balancing type switching valve 9 and a working cylinder piston device 10.

The speed-up operation is performed as follows. When the work piston operates at high speed due to the small load of the work cylinder piston device 10 and the return oil of the work cylinder piston device becomes higher than a predetermined oil pressure, the work is performed by the speed increasing hydraulic circuit according to the present invention as follows. The pressure oil supplied to the cylinder piston device 10 is replenished to increase the flow rate thereof, thereby increasing the working speed of the piston of the work cylinder piston device 10. That is, according to FIG. 1, the switching valve 3 communicates with the working cylinder piston device 10 from the port 16 via the port 11, the ducts 12, 13 and 14 on the output side,
Working cylinder piston device 10 has port 17, duct 1
8, the port 37 and the duct 19 communicate with the chamber 28 of the pressure balance type switching valve 5, and the hydraulic pressure acts on the lower side of the spool 27 in addition to the force of the compression spring 26.
7 is located at the upper end overcoming the hydraulic pressure acting on the chamber 31 of the pressure balancing type switching valve 5 which is switched from the duct 32 based on the hydraulic pressure in the chamber 31, the hydraulic pressure in the chamber 28 and the force balance with the compression spring 26. . Further, pressure oil enters the chamber 35 from the port 38 through the small hole 41 of the spool 40 of the second pressure balance type switching valve 9, and as a result, as shown in FIG.
0 is located at the left end position, and the duct 18 has a port 37,
38 from the duct 20 to the first check valve 6 and the pressure oil causes the spool 45 of the first check valve 6 to spring 4.
The force of 3 and the hydraulic pressure in the chamber 44 are overcome and pushed upward to replenish the pressure oil into the duct 14, thereby increasing the flow rate and increasing the working speed of the work cylinder piston device 10.

Normal operation is performed as follows. When the work piston operates at a low speed because the load of the work cylinder piston device 10 is large and the return oil of the work cylinder piston device is lower than a predetermined oil pressure, the pressure oil to the work cylinder piston device 10 is changed as follows. With no quantity replenishment, the working cylinder piston arrangement 10 operates at normal working speed. That is, according to FIG. 2, the hydraulic pump 1 is connected to the 3-position 3-connection switching valve 3 on the output side, and during normal operation, the 3-position 3-connection switching valve 3 is in the position as shown in FIG.
The switching valve 3 communicates with the working cylinder piston device 10 from the port 16 through the port 11, the ducts 12, 13 and 14, while the return oil flowing from the working cylinder piston device 10 through the port 37 and the duct 19 is Although the fluid pressure of the return oil is low, it communicates with the chamber 28 of the first pressure balance type switching valve 5, so that the spool of the first pressure balance type switching valve 5 is driven by the oil pressure in the duct 13 acting from the duct 32 into the chamber 31. 27 is pushed down against the hydraulic pressure in the chamber 28 and the force of the spring 26, and the hydraulic pressure in the duct 13 is reduced to the duct 3
2, through the chamber 31, the port 22 of the second pressure balancing type switching valve 9
Therefore, the spool 40 of the second pressure balancing type switching valve 9 has moved to the right end position by overcoming the force of the spring 34, and as a result, from the working cylinder piston device 10, the port 17, the duct 18, and the port 37. The oil returns from the 3-position 3-connection switching valve 3 to the tank 2 via the port 36, the duct 24, and the port 25, and the working cylinder piston device 10 operates at a normal working speed. The change in the working speed of the work cylinder piston device described above is applied to, for example, an operation in which the approach (idling) speed of the work cylinder piston device 10 is high and the work speed is low.

The return stroke is performed as follows. In the operation of moving the work piston of the work cylinder piston device 10 downward (return stroke), the pressure oil from the hydraulic pump 1 is different from that in FIGS. 1 and 2, and the switching valve positioned at the left end position on the output side. 3 to port 25.
At that time, the pressure oil from the duct 24 passes from the duct 21 to the duct 22 via the ports 29 and 30 of the first pressure balance type switching valve 5.
And the pressure oil reaches the chamber 3 on the left side of the second pressure balance type switching valve 9.
9 (FIG. 1) moves the spool 40 to the right against the force of the spring 34 in the chamber 35 (FIG. 2). As a result, the pressure oil in the duct 24 reaches the piston rod side of the working cylinder piston device 10 through the ports 36, 37, the duct 18, and the port 17. Further, the return oil on the side opposite to the piston rod of the work cylinder piston device 10 is returned to the tank 2 from the port 16, ducts 14, 13, 12 via the port 11 and via the switching valve 3. As a result, the working piston of the working cylinder piston device 10 moves downward (on the side opposite to the piston rod).

According to FIGS. 3 and 4, the hydraulic pump 1 has its suction duct connected to the oil tank 2, and the hydraulic pump 1 is connected on the output side to the 3-position 3-connection switching valve 3.
It is in the position shown in FIGS. 3 and 4. The hydraulic circuit according to the present invention is installed in the block 4, and includes a first pressure balance type switching valve 5, a first check valve 6, a second check valve 7, and a piston device 8 for opening and closing the second check valve 7. It consists of a two-pressure balancing type switching valve 9, a relief valve 52 and a working cylinder piston device 10.

When the supply of pressure oil from the pump 1 is interrupted and the switching valve 3 is in the block position, the hydraulic pressure in the chamber 50 of the piston device 8 for opening and closing the second check valve 7 is lowered. The second check valve 7 is closed, the return oil of the work cylinder piston device 10 is blocked, and the movement of the piston of the work cylinder piston device 10 is stopped and locked.

The speed-up operation is performed as follows. When the hydraulic pressure of the return oil of the work cylinder piston device 10 becomes higher than the set pressure of the relief valve 52 of FIG. 3 because the load of the work cylinder piston device 10 is low and the speed of the work piston is high, the speed increase hydraulic circuit causes The amount of pressure oil to the working cylinder piston device 10 is replenished as follows,
The flow rate is increased and the working speed of the piston of the work cylinder piston device 10 is increased. According to FIG. 3, the hydraulic pressure on the supply side of the working cylinder piston device 10 has the normal pressure discharged from the hydraulic pump 1, in which case the duct 1
The hydraulic pressure in 4 acts on the piston device 8 for opening and closing the second check valve 7 and pushes the spool 51 to the right in the chamber 50 to move the spool 48 of the second check valve 7 to the first position by the right end of the spool 51. The second check valve 7 is opened by pushing it rightward against the oil pressure of the return oil of the second check valve 7 and the force of the spring 47. Thereby, the return oil of the working cylinder piston device 10 passes through the duct 18 and through the ports 37 and 38 of the second pressure balancing type switching valve 9 to the duct 2
The first check valve 6 is reached from 0. The hydraulic pressure overcomes the force of the spring 43 of the first check valve 6 and the spool 45
To the left end to open the first check valve 6, whereby the return oil of the working cylinder piston device 10 is replenished to the supply side of the working cylinder piston device 10 to increase its flow rate to increase the flow rate of the working cylinder piston device 10. Increase work speed. When the hydraulic pressure of the return oil rises above the set pressure of the relief valve 52, the relief valve 52 is opened and the return oil is discharged from the switching valve to the tank 2 via the duct 24 and the port 25.

Normal operation is performed as follows. When the load of the work cylinder piston device 10 is large and the speed of the work piston is low and the hydraulic pressure of the return oil of the work cylinder piston device 10 is lower than the set pressure of the relief valve 52 of FIG. 4, the pressure to the work cylinder piston device 10 is reduced. Without replenishing the oil, the speed increasing hydraulic circuit shown in FIG. 4 returns the amount of the pressure oil to the normal flow rate as described below, and the working cylinder piston device 10 is operated at the normal working speed. That is, according to FIG. 4, the hydraulic pressure on the supply side of the working cylinder piston device 10 has a normal pressure discharged from the hydraulic pump 1. In the first pressure balance type switching valve 5, the duct 32 is connected to the chamber 3
The spool 27 resists the force of the spring 26 by the pressure oil introduced into the chamber 31 of the first pressure balance type switching valve 5, which is switched based on the force balance between the oil pressure in the valve 1 and the oil pressure in the chamber 28 and the force of the spring 26. Since it is pushed down to the lower end, the pressure oil in the port 21 reaches the port 22 through the chamber 29 and the chamber 30 of the first pressure balancing type switching valve 5, and the spool of the second pressure balancing type switching valve 9 is reached. By moving 40 to the right end, the return oil of the duct 18 is made to flow directly from the switching valve 3 to the tank 2 via the duct 24 and the port 25. As a result, the return oil from the work cylinder piston device 10 passes through the duct 18, the port 36 of the second pressure balancing type switching valve 9 and the duct 24, the port 2.
5 to the tank 2 and the working cylinder piston arrangement 10 operates at normal working speed. The above-described operation of the work cylinder piston device is applied to the operation of the work cylinder piston device 10 where the approach (idling) speed is high and the work speed is low.

The return stroke is performed as follows. The operation of raising the piston of the work cylinder piston device 10 is as follows. Since the pressure oil from the port 25 communicates with the port 22 of the second pressure balance type switching valve 9,
The spool 40 of the pressure balance type switching valve 9 moves to the right side and opens the port 25, whereby the pressure oil flows to the port 17, and the second check valve 7 is opened without operating the pilot piston 51 of the piston device 8. The pressure oil enters the piston rod side of the working cylinder piston device 10. Since the pressure oil of the port 17 is also communicated with the chamber 28 of the first pressure balancing type switching valve 5 via the duct 18, the port 37 and the duct 19, the piston 27 of the first pressure balancing type switching valve 5 has the chamber 31. Of the working cylinder piston device 10 on the side opposite to the piston rod is
6, through ducts 14, 13, 12 and port 11 to tank 2 to raise the working piston of the working cylinder piston arrangement. That is, the work piston of the work cylinder piston device 10 moves upward (on the side opposite to the piston rod). At that time, port 1 of the working cylinder piston device 10
As for the hydraulic pressure on the side of 7, the pressure oil is duct 18, port 37,
The relief valve 52 communicates with the duct 57 and is adjusted to the set hydraulic pressure of the relief valve 52.

[0015]

According to the present invention, the speed of the working piston is increased or decreased according to the magnitude of the load, that is, the approach (idling) speed of the working piston is increased, the working speed is decreased, and the working piston is decreased. By reversing the direction of movement of the hydraulic drive, the hydraulic drive can be efficiently and multi-directionally operated, in which case a speed-up hydraulic circuit can be obtained which guarantees the safety of the operation of the working cylinder.

[Brief description of drawings]

FIG. 1 is a diagram showing a speed increasing state of a speed increasing hydraulic circuit according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a normal operating state of the speed increasing hydraulic circuit according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a speed increasing state of a speed increasing hydraulic circuit according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a normal operating state of a speed increasing hydraulic circuit according to a second embodiment of the present invention.

[Description of sign]

 1 hydraulic pump 2 tank 3 3 position 3 connection switching valve 5 first pressure balancing type switching valve 6 first check valve 9 second pressure balancing type switching valve 10 working cylinder piston device 11 port 12 duct 13 duct 14 supply side duct 16 port 18 Return Duct 20 Duct 24 Duct 26 Spring 28 First Pressure Balance Type Switching Valve Chamber 31 First Pressure Balance Type Switching Valve Chamber 52 Relief Valve

Claims (2)

(57) [Claims] 1. In a speed-up hydraulic circuit, a pressure oil pipeline from a hydraulic pump (1) is provided with a port (11), a duct (12) and a duct (1) at an output side of a switching valve (3).
3), connected to the work cylinder piston device (10) from the port (16) via the duct (14), and the return side duct (18) of the work cylinder piston device (10)
Is connected to the first pressure balance type switching valve (5) and the first check valve (6) via the second pressure balancing type switching valve (9), and is connected to the return side of the working cylinder piston device (10). When the hydraulic pressure is higher than a predetermined pressure, the first check valve (6) is directly opened by the action of the hydraulic pressure of the return oil in the duct (20) on the supply side of the first check valve (6) to open the working cylinder. When the return oil is supplied to the supply side duct (14) of the piston device (10) and the hydraulic pressure on the return side of the working cylinder piston device (10) is lower than a predetermined pressure, the first pressure balance type switching valve The first pressure equilibrium type switching is performed by switching the first pressure equilibrium type switching valve (5) based on the hydraulic pressure in the chamber (31) of (5), the hydraulic pressure in the chamber (28) and the force balance by the compression spring (26). Pressure oil flows through the chamber (31) of the valve (5) into the second pressure balancing valve (9 A duct for communicating the return oil of the working cylinder piston device (10) to the switching valve (3) connected to the tank (2) by switching the second pressure balancing type switching valve (9) by pushing the spool (40) of the tank (2). (24) The pressure-increasing hydraulic circuit, wherein the pressure-increasing hydraulic circuit is configured to discharge the gas through a second pressure balancing type switching valve (9). 2. In the speed-up hydraulic circuit, the pressure oil line from the hydraulic pump (1) is provided with a port (11), a duct (12), and a duct (1) at the output side of the switching valve (3).
3), connected to the work cylinder piston device (10) from the port (16) through the duct (14), and the duct (18) on the return side of the work cylinder piston device (10)
Is connected to the first pressure balancing type switching valve (5), the first check valve (6) and the relief valve (52) via the second pressure balancing type switching valve (9), and the working cylinder piston device When the oil pressure on the return side of (10) is higher than the set pressure, the first check valve (6) is directly operated by the oil pressure of the return oil in the duct (20) on the supply side of the first check valve (6). Is opened to supply the return oil to the supply side duct (14) of the work cylinder piston device (10), and when the return side hydraulic pressure of the work cylinder piston device (10) is lower than the set pressure, the first Second pressure balance by switching the first pressure balance type switching valve (5) based on the hydraulic pressure in the chamber (31) of the pressure balancing type switching valve (5), the hydraulic pressure in the chamber (28) and the force balance of the compression spring (26). Working cylinder piston device by switching the mold switching valve (9) The return oil of 10) is discharged to a duct (24) communicating with a switching valve (3) connected to a tank (2) via a second pressure balancing switching valve (9). Speed hydraulic circuit.