JPH09210007A - Hydraulic circuit of hydraulic cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate switching time, improve hit rate, and provide space and cost reduction by forming an accumulator in a two-pressure circuit into a pressure sealing type, and selecting the accumulator as necessary. SOLUTION: This hydraulic circuit is provided with a cartridge solenoid valve 45A which includes an accumulator 47 for high pressure, and a cartridge solenoid valve 45B which includes an accumulator 49 for low pressure, branched from the discharge side pipe line 37 of a variable displacement hydraulic pump 35 at a hydraulic circuit 27 for driving a hydraulic cylinder 17. By selecting the necessary accumulators 47, 49 through the cartridge solenoid valves 45A, 45B, it is possible to eliminate switching time, thus improving hit rate and providing space and cost reduction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit for a hydraulic cylinder, and more particularly to a hydraulic circuit for a hydraulic cylinder, which is an improved two-pressure hydraulic circuit for driving the hydraulic cylinder.

[0002]

2. Description of the Related Art Conventionally, as a two-pressure hydraulic circuit for driving a punch driving hydraulic cylinder provided in a turret punch press, for example, two accumulators (for high pressure and low pressure) are used.
They are selectively used depending on the switching valves that are used as needed.

As a two-pressure hydraulic circuit for driving the hydraulic cylinder, for example, the hydraulic circuit shown in FIG. 4 is known. That is, the hydraulic circuit 101 includes the pump motor 10 from the tank 103 via the filter 105.
7 is provided with a variable displacement hydraulic pump 109, and a discharge side pipeline 111 of the variable displacement hydraulic pump 109 is provided.
Communicates with the P port of the 3-position electromagnetic switching valve 117 via the check valve 113 and the filter 115. An electromagnetic switching valve 123 that branches to switch between the high pressure accumulator 119 and the low pressure accumulator 121 is provided in the middle of the discharge side pipeline 111.

When the flow path of the three-position solenoid operated directional control valve 117 is switched so that the P port and the A port and the B port and the T port are communicated with each other, the pressure oil passes through the pipe 125 and the hydraulic cylinder 127.
To the upper oil chamber 129, and the piston rod 131 is lowered. Then, the lower oil chamber 133 of the hydraulic cylinder 127
The pressure oil discharged further enters the B port of the three-position switching valve 117 through the pipe 135 and returns from the T port to the return pipe 137.
The pressure oil is returned to the tank 103 through the. In addition, a pulsation prevention damper 139 for preventing pulsation is provided in the middle of the return pipe 137.
Is provided. Reference numeral 141 is a stop valve,
Reference numeral 143 is a check valve operated by pilot pressure, and a cooler 145 is provided at the end of the return pipe 137.

Next, when the ports of the 3-position solenoid operated directional control valve 117 are switched so that the P port and the B port and the A port and the T port are communicated with each other, the pressure oil supplied from the discharge side pipeline 111 is changed to the P port. Then, the oil is supplied to the lower oil chamber 133 provided in the hydraulic cylinder 127 through the pipe line 135 through the B port.

When pressure oil is supplied to the lower oil chamber 133, the piston rod 131 rises, and the oil in the upper oil chamber 129 passes through the pipe 125, the A port, the T port, and the return pipe 137. It is returned to the tank 103.

With the above structure, the three-position electromagnetic switching valve 117
The piston rod 131 provided on the hydraulic cylinder 127 can be moved up and down by switching the ports of the above, and the desired punching can be performed on the work by the movement of the piston rod 131.

Next, in order to set the line to the high pressure line or the low pressure line, the electromagnetic switching valve 123 is operated to connect the P port and the A port and the B port and the T port. Then, the pressure oil flowing in from the discharge side pipe line 111 passes through the branched pipe line 147 and communicates with the low pressure accumulator 121 from the P port through the A port, and the line pressure is set to a low pressure. On the other hand, the high pressure accumulator 119
The pressure oil in the inside is returned from the B port to the tank 103 via the T port, the pipe line 149 and the return pipe line 137.

When the electromagnetic switching valve 123 is operated to connect the P port and the B port, and the A port and the T port, the pressure oil flowing from the discharge side pipe line 111 passes through the branched pipe line 147. The line pressure is set to a high pressure by communicating with the high pressure accumulator 119 from the P port through the B port. Then, the pressure oil in the low-pressure accumulator 121 is returned from the A port to the T port through the pipe line 149 and the return pipe line 137 to the tank 103. The configuration of the hydraulic circuit 101 as described above is generally adopted.

[0010]

By the way, the two-pressure circuit 10 for driving the above-mentioned conventional hydraulic cylinder 127 is provided.
When the high pressure line and the low pressure line are switched by the electromagnetic switching valve 123, one of the high and low pressure accumulators 119 and 121 which is not used is a circuit for discharging the oil in the accumulator to the tank 103. ing.

Even if the low pressure line is switched to the high pressure line, it takes a long time to accumulate the pressure in the high pressure accumulator 119, and there is a problem that punching cannot be started immediately. The electromagnetic switching valve 123 for switching between the high pressure line and the low pressure line is expensive.

The object of the present invention is to make the accumulator in the two pressure circuits into a pressure-sealed type and select the accumulator as required, thereby eliminating the switching time, improving the hit rate, saving space, and reducing costs. An object of the present invention is to provide a hydraulic circuit of a hydraulic cylinder that is reduced in number.

[0013]

In order to achieve the above object, the hydraulic circuit of the hydraulic cylinder of the present invention according to claim 1 is a two-pressure circuit for driving the hydraulic cylinder, and the hydraulic pressure provided in the two-pressure hydraulic circuit. It is characterized in that a high pressure accumulator is provided branching to a discharge side pipe line of the pump via a cartridge solenoid valve, and a low pressure accumulator is provided branching to the discharge side line via a cartridge solenoid valve. It is a thing.

The hydraulic circuit of the hydraulic cylinder of the present invention according to claim 2 is characterized in that the hydraulic cylinder is a drive device for reciprocating the punch of the punch press.

With the hydraulic circuit of the hydraulic cylinder according to the above-mentioned claims 1 and 2, the discharge side pipes of the hydraulic pump are provided with high pressure via the cartridge solenoid valves, respectively.
An accumulator for low pressure is provided to increase the pressure depending on the required pressure.
Select a low pressure accumulator and send oil to the hydraulic cylinder.

Since the switching time is eliminated, the hit rate can be increased, the space can be saved, and the cost can be reduced.
In fact, since the expansion and contraction of oil is suppressed to the minimum, the life of the accumulator can be extended.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Although the present embodiment is directed to a turret punch press as an example, the present invention is not limited to this model.

First, in order to facilitate understanding, the turret punch press will be briefly described.

Referring to FIG. 3, the turret punch press 1 is provided with a gate-shaped frame 3. This frame 3 includes a lower base 5, side frames 7 standing on the lower base 5, and a frame 7. It is composed of an upper frame 9 provided on the upper part.

A rotatable lower turret 11 is supported on the lower base 5, and a plurality of dies D are mounted on the circumference of the lower turret 11 at appropriate intervals. A rotatable upper turret 13 is supported on the upper frame 9 corresponding to the lower turret 11, and a plurality of punches P are mounted on the upper turret 13 at a position corresponding to the die D.

FIG. 3 of the lower and upper turrets 11, 13
, The position of the die D and the punch P mounted on the right side is the processing position.
A striker 15 is provided on the upper frame 9 above and below so as to be vertically movable. The striker 15 is connected to a hydraulic cylinder 17 as a drive device provided in the upper frame 9 via a ram 19, for example.

At the right end in FIG. 3 on the lower base 5, there is provided a carriage base 21 which is movable in the Y-axis direction (left and right direction in FIG. 3). This carriage base 21 is in the X-axis direction. A carriage 23 that is movable in the direction (perpendicular to the paper surface in FIG. 3) is provided. The carriage 23 is provided with a plurality of work clamps 25 that clamp the work W at appropriate intervals in the X-axis direction.

With the above construction, by moving the carriage base 21 in the Y-axis direction and the carriage 23 in the X-axis direction, the workpiece W clamped by the workpiece clamp 25 provided on the carriage 23 is moved in the X-axis and Y-axis directions. The workpiece W is moved in the direction, and the desired position of the work W is positioned at the processing position.

With the desired position of the work W positioned at this processing position, the upper and lower turrets 13, 11 are placed.
Is rotated to index and position the desired punch P and die D at the processing position. Next, by driving the hydraulic cylinder 17 to move the striker 15 up and down via the ram 19, normal punching is performed at a desired position of the work W by cooperation of the punch P and the die D. .

Next, the hydraulic circuit 27 for supplying pressure oil to the hydraulic cylinder 17, which is the main part of the embodiment of the present invention, will be described in detail. Since each device provided in the hydraulic circuit 27 is already known, the description of its structure will be omitted.

Referring to FIG. 1, the hydraulic circuit 27 is provided with a variable displacement hydraulic pump 35 driven by a pump motor 33 from a tank 29 through a filter 31. The discharge of the variable displacement hydraulic pump 35 is provided. The side conduit 37 communicates with the P port of the three-position electromagnetic switching valve 43 via the check valve 39 and the filter 41. A high pressure accumulator 47 is provided via the cartridge solenoid valve 45A and a low pressure accumulator 49 is provided via the cartridge solenoid valve 45B.

Further, a shutoff valve 51 is provided in the middle of the discharge side pipeline 37 so as to be branched, and the shutoff valve 5 is provided.
In No. 1, the circuit is normally closed, and when the power of the line is turned off, the circuit is opened to return the oil to the tank 29.

When the flow path of the three-position electromagnetic switching valve 43 is switched so that the P port and the A port and the B port and the T port are communicated with each other, the pressure oil flows into the upper oil chamber 55 of the hydraulic cylinder 17 through the pipe line 53. Then, the piston rod 57 is lowered. Then, the pressure oil discharged from the lower oil chamber 59 of the hydraulic cylinder 17 enters the B port of the three-position electromagnetic switching valve 43 through the conduit 61, the T port through the return conduit 63, and the tank 29.
The pressure oil is returned to. Further, a pulsation prevention damper 65 for preventing pulsation is provided in the return pipe 63. Reference numeral 67 is a stop valve, reference numeral 69 is a check valve operated by pilot pressure, and a cooler 71 is provided at the end of the return pipe 63.

Next, when the ports of the 3-position solenoid operated directional control valve 43 are switched so that the P port and the B port and the A port and the T port are communicated with each other, the pressure oil supplied from the discharge side conduit 37 is the P port. Further, it is supplied to the lower oil chamber 59 provided in the hydraulic cylinder 17 through the pipe line 61 through the B port.

When pressure oil is supplied to the lower oil chamber 59, the piston rod 57 rises, and the oil in the upper oil chamber 55 flows to the pipeline 53.
Through the return port 63 from the A port to the T port and returned to the tank 29.

With the above structure, the piston rod 57 provided on the hydraulic cylinder 17 can be moved up and down by switching the port of the three-position electromagnetic switching valve 43, and the desired punching work can be performed on the workpiece by the movement of the piston rod 57. Can be given.

Next, in order to set the line to the high pressure line or the low pressure line, referring also to FIG. 2, the cartridge solenoid valve 45A is provided in the conduit 73 branched from the discharge side conduit 37, A high-pressure accumulator 47 communicates with the open circuit of the cartridge solenoid valve 45A. Further, the cartridge solenoid valve 45B is provided in a pipe line 75 branched from the discharge side pipe line 37, and a low pressure accumulator 49 communicates with an open circuit of the cartridge solenoid valve 45B.

The high pressure accumulator 47 is
It is used for high-pressure punching.
It is 0 kgf / cm ² . The low-pressure accumulator 49 is used for low-pressure punching, and the filling pressure is, for example, 85 kgf / cm ² .

Actually, the electromagnetic switching valve 123 used as the conventional example is expensive, but the cartridge solenoid valves 45A and 45B are inexpensive and the cost is reduced. This cartridge solenoid valve 45
A and 45B open the circuit of the valve on the side to be used when using either the high or low pressure accumulator 47 or 49, and close the circuit of the valve on the side not to use so that oil is enclosed in the accumulator. ing.

Further, a shutoff valve 51 is provided in a pipe line 77 branched from the discharge side pipe line 37, and an outlet side of the shutoff valve 51 communicates with a tank 29 through a return pipe line 63. Reference numeral 79 is a throttle valve. The shutoff valve 51 is for returning oil to the tank 29 when the power is turned off, and the circuit is normally closed.

With the above-described structure, the high pressure and low pressure accumulators 47 and 49 can be selected by the cartridge solenoid valves 45A and 45B to instantaneously supply oil to the hydraulic cylinder 17. Thus,
Since the switching time between the high pressure line and the low pressure line is eliminated, the hit rate can be improved, and since the manifold and the expensive solenoid valve are not required, the space can be saved and the cost can be reduced. Since the expansion and contraction of oil in the hole is minimized, the life of the accumulator can be extended.

The present invention is not limited to the above-described embodiments of the present invention, but can be embodied in other forms by making appropriate changes.

[0038]

As will be understood from the above description of the embodiments, the present invention according to claims 1 and 2 is branched into the discharge side pipeline provided in the two-pressure hydraulic circuit. Each cartridge solenoid valve was provided, and the cartridge solenoid valve was provided with high and low pressure accumulators.

Thus, the oil in the accumulator can be switched to the high pressure line and the low pressure line with no switching time while accumulating the pressure, the hit rate can be improved, and the space can be saved and the cost can be reduced. Further, since the expansion and contraction of oil is suppressed to the minimum, the life of the accumulator can be extended.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a hydraulic circuit of a hydraulic cylinder showing a main part of the present invention.

FIG. 2 is an enlarged explanatory diagram of a hydraulic circuit taken along a line II in FIG.

FIG. 3 is a front explanatory view showing a schematic configuration of a hydraulic turret punch press which is an example of an embodiment for carrying out the present invention.

FIG. 4 is an explanatory diagram of a hydraulic circuit of a hydraulic cylinder showing a conventional example.

[Explanation of symbols]

 1 Turret Punch Press 17 Hydraulic Cylinder 27 Hydraulic Circuit 35 Variable Displacement Type Hydraulic Pump (Hydraulic Pump) 37 Discharge Side Pipeline 45A, 45B Cartridge Solenoid Valve 47 High Pressure Accumulator 49 Low Pressure Accumulator P Punch

Claims (2)

[Claims] 1. A two-pressure hydraulic circuit for driving a hydraulic cylinder, is branched to a discharge side pipe line of a hydraulic pump provided in the two-pressure hydraulic circuit, and a high-pressure accumulator is provided through a cartridge solenoid valve. A hydraulic circuit of a hydraulic cylinder, characterized in that a low pressure accumulator is provided via a cartridge solenoid valve by branching to a discharge side pipe line. 2. A hydraulic circuit for a hydraulic cylinder according to claim 1, wherein the hydraulic cylinder is a drive device for reciprocating a punch of a punch press.