JP2921689B2 - Hydraulic device of hydraulic press machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic device for a hydraulic press machine that performs a process such as punching on a work.

(Prior Art) Conventionally, a turret punch press or the like mainly uses a mechanical system in which a crank is driven by an electric motor to move up and down a ram, and press working is performed by a punch and a die. In this mechanical system configuration, the vertical movement speed of the ram is fixed and very high, so when performing punching work on the work, the impact sound is loud and there is some problem with noise countermeasures. In many cases, the driving method is changed from a mechanical type to a hydraulic type.

In this hydraulic type, that is, in the configuration in which the ram is moved up and down by a hydraulic cylinder to perform press working between the punch and the die, the vertical movement speed of the ram is reduced to reduce noise, and the impact during punching by the punch is reduced. When the sound was lowered, the hit rate was greatly reduced, resulting in a decrease in productivity.

(Problems to be solved by the invention) By the way, in order to reduce noise as described above,
If the speed of the vertical movement of the ram by the hydraulic cylinder is reduced to suppress the impact sound during punching, there is a problem that the hit rate is greatly reduced and the production efficiency is deteriorated.

An object of the present invention is to lower a ram by a hydraulic cylinder,
That is, the approach process in which the punch moves and approaches the surface of the work is lowered at a high speed, and the punch is brought into contact with the work to perform the punching process. It is an object of the present invention to provide a hydraulic device of a hydraulic press mechanism that can perform punching without lowering a hit rate by performing a quick approach process and raising a ram at a high speed.

[Constitution of the Invention] (Means for Solving the Problems) In view of the above-mentioned conventional problems, the present invention operates the punch to press a work disposed between a punch and a die. Hydraulic device for a hydraulic press machine comprising a hydraulic cylinder having a piston for vertically moving the hydraulic circuit, a first circuit connected to a supply-side cylinder chamber on the piston head side of the hydraulic cylinder, and a second circuit connected to a hydraulic pump. A third circuit connected to a discharge-side cylinder chamber on the rod side of the hydraulic cylinder, a fourth circuit connected to the first circuit, and the lift A fifth circuit connected to a control valve, a connection of the third circuit is provided by arranging a differential control valve capable of switching between the fourth circuit and the fifth circuit;
A pilot check valve that normally prevents the discharge of pressure oil is disposed and provided in a sixth circuit that connects the circuit of (a) and a discharge circuit that is connected to the lift control valve. The fifth circuit and the fifth circuit are alternately connected to the second circuit and the discharge circuit so as to be freely switched, and the supply of the hydraulic cylinder is performed during an approach step of lowering the piston and moving the punch in the die direction. Switching control of the elevation control valve and the differential control valve to supply pressure oil to the side cylinder chamber and to recirculate pressure oil discharged from the discharge side cylinder chamber of the hydraulic cylinder to the supply side cylinder chamber, When the pressurized oil discharged from the discharge-side cylinder chamber immediately before the punch comes into contact with the work is discharged to the discharge circuit, and the piston is moved up and down, the supply-side cylinder is An NC device for switching and controlling the lift control valve and the differential control valve so as to discharge the internal pressure oil to the discharge circuit via the lift control valve and the pilot check valve. .

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 4, for example, a hydraulic turret punch press 1 as a hydraulic press machine is integrally formed with a lower frame 3, a column 5 and an upper frame 7 into a C-shape. In a processing portion between the lower frame 3 and the upper frame 7, a rotatable lower turret 11 is provided on a shaft 9 provided on the lower frame 3, and a shaft 13 provided on the upper frame 7 is provided with a lower portion. A rotatable upper turret 15 is supported on each. In addition, the lower turret 11 and the upper turret 15 are rotated in synchronization.

A plurality of punches 17 as upper dies are mounted on the circumference of the upper turret 15, and dies 19 as lower dies are mounted on the circumference of the lower turret 11 at positions corresponding to the punches 17, respectively. The upper frame 7 is provided with a hydraulic cylinder 21.

A table 23 is provided on the lower frame 3 so as to be movable in the left-right direction in FIG. 4 (hereinafter referred to as the Y-axis direction). A carriage base 25 is attached to the left end of the table 23. The carriage base 25 is provided with a carriage 27 which is movable in a direction perpendicular to the paper surface in FIG. 4 (hereinafter, referred to as an X-axis direction). A plurality of work clamps 29 capable of freely clamping the work W are attached to the carriage 27.

With the above-described configuration, by operating the hydraulic cylinder 21 to move the punch 17 up and down on the work W clamped by the work clamp 29, a predetermined press working is performed in cooperation with the punch 17 and the die 19, By moving the work W in the X-axis and Y-axis directions, a plurality of press workings are performed on the work W.

As shown in FIG. 2, the punch 17 is mounted on the upper turret 15 via a punch holder 31, and a gap is formed between a groove 15V formed in the upper turret 15 and the punch holder 31. , The lifter spring 33 is urged upward and interposed, and the punch 17 and the punch holder
A stripper spring 35 is interposed between the first spring 31 and the second spring 31 so as to urge upward.

2 and 1, which show a specific configuration of the hydraulic cylinder 21, a piston 37 is mounted on the hydraulic cylinder 21 so as to be movable up and down. Is supported. A striker 45 is attached to the lower end of the ram 41 with a plurality of bolts 43.

In the hydraulic cylinder 21, with a piston 37 as a boundary,
A supply side cylinder chamber 47 is formed in an upper part, and a discharge side cylinder chamber 49 is formed in a lower part. An oil passage 51 communicating with the supply-side cylinder chamber 47 is formed in the upper part of the hydraulic cylinder 21. The oil passage 51 is connected to a lifting control valve 55 shown in FIG. I have.

The elevating control valve 55 includes a descending position a, an ascending position b, and a stop position N, and is controlled by an NC device (not shown).

A hydraulic pump is connected to the elevation control valve 55 through a circuit 57.
59 is connected.

One end of a circuit 61 is connected to the hydraulic pump 59, and the other end of the circuit 61 is connected to an oil tank 65 through a filter 63.
Is communicated to. The hydraulic pump 59 has a drive motor 67
Are linked together. An oil passage 69 communicating with the discharge side cylinder chamber 49 of the hydraulic cylinder 21 is formed. The oil passage 69 is connected to a differential control valve 75 of a hydraulic differential circuit 73 via a circuit 71.

The differential control valve 75 includes a discharge position A and an ascending position B. In the discharge position A, only the discharge valve is opened and the supply valve is closed. In the ascending position B, both the supply and discharge valves function normally, and are controlled by the NC device.

The discharge position A of the differential control valve 75 is communicated with the circuit 53 via the circuit 77 and is communicated with the supply side cylinder chamber 47.
The ascending position B is connected to the elevating control valve 55 and the circuit 81 via the circuit 79.
Through a pilot check valve 83.

A circuit 85 as a return circuit is connected to the lift control valve 55 and communicates with the oil tank 65. Note that this circuit 85
Is also connected to a circuit 87 connected to the pilot check valve 83. Hydraulic pump during press working
A relief valve 91 is connected via a circuit 89 in the middle of the circuit 57 as a relief circuit for hydraulic pressure when an overload is applied to 59 and the drive motor 67.
91 is connected to the oil tank 65 by a circuit 93.

A pilot circuit having a pilot check valve 83 includes a circuit 95 communicating with the circuits 53 and 77, and a circuit
And a pilot circuit 81 communicating with the pilot circuit 81. When the elevation control valve 55 is switched to the elevation position b, the pilot check valve 83 is opened by the hydraulic pressure of the pilot circuit 81, and the exhaust hydraulic pressure of the supply-side cylinder chamber 47 is changed from the circuit 53 to the elevation position b of the elevation control valve 55. Through the circuit 85, the circuit 95, the pilot check valve 83 and the circuit 87, the oil is discharged to the oil tank 65, and the piston 37 is quickly raised.

With the above configuration, by driving the drive motor 67, the hydraulic pump 59 is operated and the oil in the oil tank 65 is discharged to the circuit 57 via the filter 63 and the circuit 61. This circuit 57
1 and 3, the oil discharged to is moved to the lowering position a of the raising / lowering control valve 55, and the raising / lowering control valve 55 is controlled by a NC device (not shown) based on a predetermined lowering pattern. Then, it is fed into the supply side cylinder chamber 47 of the hydraulic cylinder 21 through the circuit 53 and the oil passage 51. Also, hydraulic cylinder 21
The oil discharged from the discharge side cylinder chamber 49 is pushed down by the oil fed into the supply side cylinder chamber 47, so that the oil passes through the oil passage 69 and the circuit 71 to the discharge position A of the differential control valve 75. Sent in. Since the differential control valve 75 is in the OFF state, the discharged oil is supplied to the circuit 53 via the circuit 77.
While being pressurized by the piston 37, the oil joins the oil from the elevation control valve 55 and pressurizes the supply-side cylinder chamber 47 in an increased amount. The hydraulic pressure of the supply-side cylinder chamber 47 that has been increased and pressurized is
By rapidly lowering the piston 37, the time of the approach step of the punch 17 via the ram 41 is reduced.

Next, immediately before the punch 17 contacts the surface of the workpiece W,
By the operation of the NC device, the differential control valve 75 turns ON and the discharged oil
The outflow to the circuit 77 is stopped, and is sent to the descending position a of the elevation control valve 55 via the circuit 79. The discharged oil returns to the oil tank 65 via a return circuit 85 connected to the elevation control valve 55.

As described above, immediately before the punch 17 comes into contact with the surface of the workpiece W, the discharged oil in the discharge-side cylinder chamber 49 stops increasing the pressure of the supply-side cylinder chamber 47, so that the supply-side cylinder chamber 47 is stopped.
Since the pressure rapidly decreases and the descending speed of the piston 37 decreases, the impact sound when punching the workpiece W by the punch 17 can be reduced.

Next, after the punching is completed, the lift control valve 55 is moved to the raised position b.
Switched under the control of the NC device, the oil from the hydraulic pump 59 is sent to the ascending position B of the differential control valve 75 via the circuit 79, and is discharged via the connected circuit 71 and the oil passage 69 to the discharge side cylinder. It is sent to room 49.

The ram 41 rapidly rises via the piston 37 by the oil sent to the discharge side cylinder chamber 49 of the hydraulic cylinder 21. At the same time, the supply side cylinder chamber 47 of the hydraulic cylinder 21
The oil flows through the oil passage 51 and the circuit 53 by the rise of the piston 37, passes through the ascending position b of the elevation control valve 55, passes through the circuit 85, the circuit 95, the pilot check valve 83 and the circuit 87 to the oil tank 65. The oil is drained and the piston 37 is quickly raised.

By having the hydraulic lifting circuit and the hydraulic operating circuit in the hydraulic punch press 1 as described above, the approach process can be performed quickly, the punching process can be performed slowly, and the press work can be performed with low noise without lowering the productivity.

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

[Effects of the Invention] As can be understood from the above description of the embodiment, in the present invention, the switching control of the elevation control valve 55 and the differential control valve 75 is performed by the NC device, so that the hydraulic cylinder is controlled during the approach process. Pressure oil is supplied to the supply-side cylinder chamber 47 of the hydraulic cylinder 21 and the pressure oil discharged from the discharge-side cylinder chamber 49 of the hydraulic cylinder 21 is returned to the supply-side cylinder chamber 47, and immediately before the punch 17 contacts the workpiece W. Is switched to discharge the pressurized oil discharged from the discharge side cylinder chamber 49 to the discharge circuit 85, so that it moves at high speed during the approach process and moves at low speed just before the punch 17 comes into contact with the work W. It becomes something.

Therefore, according to the present invention, it is possible to easily switch from the high-speed movement to the low-speed movement with a simple configuration and to perform the ascent return by the high-speed movement, so that the efficiency can be improved. In addition, noise generation during processing can be suppressed by the low-speed movement.

Further, when the piston 37 of the hydraulic cylinder 21 is raised, the pressure oil in the supply-side cylinder chamber 47 is discharged to the discharge circuit 85 via the elevation control valve 55 and the pilot check valve 83, so that the discharge resistance is reduced. The piston 37 can be raised at a high speed.

[Brief description of the drawings]

FIG. 1 is a main path diagram of a hydraulic device of a hydraulic press machine according to the present invention, FIG. 2 is an enlarged cross-sectional view taken along the arrow II in FIG. 1,
FIG. 3 is a ram stroke diagram, and FIG. 4 is a side view of a hydraulic turret punch press according to an embodiment of the present invention. 17 …… Punch, 19 …… Die, 21 …… Hydraulic cylinder 37 …… Piston, 41 …… Ram, 47 …… Supply side cylinder chamber 49 …… Discharge side cylinder chamber, 73 …… Hydraulic differential circuit 75 …… Differential control valve, W …… Work

Claims (1)

(57) [Claims] 1. A piston (37) for operating a punch (17) for press-working a work (W) disposed between a punch (17) and a die (19) so as to be vertically movable. A hydraulic circuit for a hydraulic press machine provided with a hydraulic cylinder (21), comprising: a first circuit (53) connected to a supply side cylinder chamber (47) on the piston head side of the hydraulic cylinder (21); An elevation control valve (55) is arranged and provided between the hydraulic cylinder (21) and the second circuit (57) connected to the second circuit (57).
9) and a third circuit (71) connected to the first circuit (5).
The third circuit (77) connected to 3) and the elevation control valve (5)
A differential circuit capable of switching the connection of the third circuit (71) to the fourth circuit (77) and the fifth circuit (79) between the fifth circuit (79) and the fifth circuit (79). A sixth circuit (87) in which a control valve (75) is arranged and provided, and the first circuit (53) is connected to a discharge circuit (85) connected to the elevation control valve (55).
In a normal state, a pilot check valve (83) for preventing discharge of pressurized oil is arranged and provided.
5) The first circuit (53) and the fifth circuit (79) are alternately connected and switched to the second circuit (57) and the discharge circuit (85), and the piston (37) During the approach step of moving the punch (17) in the direction of the die (19) by lowering the hydraulic cylinder (21), pressurized oil is supplied to the supply-side cylinder chamber (47) of the hydraulic cylinder (21) and the hydraulic cylinder (21) Switching control of the elevation control valve (55) and the differential control valve (75) to recirculate the pressure oil discharged from the discharge side cylinder chamber (49) to the supply side cylinder chamber (47);
Immediately before the punch (17) comes into contact with the work (W), pressure oil discharged from the discharge side cylinder chamber (49) is discharged to the discharge circuit (85), and the piston (37) is moved up and down. At this time, the pressure oil in the supply side cylinder chamber (47) is
A switching control valve for controlling the lifting / lowering control valve (55) and the differential control valve (75) to discharge to the discharge circuit (85) via the lifting / lowering control valve (55) and the pilot check valve (83). A hydraulic device for a hydraulic press machine, comprising an NC device.