JPH0639599A - Hydraulic press - Google Patents

Abstract

PURPOSE:To accelerate stroke speed with a hydraulic system of simple constitution. CONSTITUTION:A double cylinder 2 having a small diameter oil chamber A1, a large diameter oil chamber A3 a return side oil chamber A2 is used between a piston 9 and a cylinder 8. A cooling oil switch over supply device 5 for connecting a cooling oil supply system 4 in place of a pressure oil supply system 3 is mounted on the large diameter oil chamber A3 of this double cylinder 2. The cooling oil supply system 4 can cool any place necessary in a press apparatus.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a punch press having a double cylinder and other hydraulic presses.

[0002]

2. Description of the Related Art In hydraulic presses such as punch presses,
Various configurations have been adopted as means for increasing the stroke speed and improving the productivity. For example, there are a pump that has a large capacity to supply hydraulic oil at a high speed, and a pump that uses a so-called double pump.

[0003]

However, if the pump has a large capacity or a double pump, the hydraulic system including auxiliary equipment becomes complicated. Further, in the case of using the double pump, the stroke speed easily varies depending on the magnitude of the load.

In order to solve such a problem,
The one using a double cylinder having two large and small oil chambers on the driving side was considered. This is to operate at high speed from the top dead center to the middle point by supplying hydraulic pressure to the small-diameter oil chamber, and to supply hydraulic pressure to both oil chambers at the time of punching to obtain a pressing force required for punching. However, since separate hydraulic pumps are used for the large and small oil chambers, respectively, the hydraulic system also becomes complicated.

An object of the present invention is to provide a hydraulic press which can improve the stroke speed with a hydraulic system having a simple structure.

[0006]

A hydraulic press according to the present invention comprises a small-diameter oil chamber and a large-diameter oil chamber for applying a hydraulic pressure in the forward direction between a piston and a cylinder, and a return-side oil chamber for applying a hydraulic pressure in the reverse direction. It uses the double cylinder which it has. In the large-diameter oil chamber of the double cylinder, a cooling oil switching / supplying device that connects the cooling oil supply system by switching to the pressure oil supply system is provided. The cooling oil supply system may be for cooling any place required in the press machine.

[0007]

Operation: From top dead center to a predetermined intermediate point, pressure oil is supplied to the small-diameter oil chamber to move the piston at high speed with respect to the cylinder. At this time, since the capacity of the large diameter oil chamber gradually increases, the cooling oil is supplied from the cooling oil supply system to prevent the large diameter oil chamber from becoming negative pressure. After the intermediate point, pressure oil is supplied to both the small diameter oil chamber and the large diameter oil chamber. As a result, the stroke speed is reduced, but a large pressing force required for the press can be obtained. The return operation is performed by supplying pressure oil to the return side oil chamber.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. This hydraulic press uses a double cylinder 2 for raising and lowering a punch die 1, and switches it to a pressure oil supply system 3 including a pump P1 to connect a cooling oil supply system 4 to the double cylinder 2 for cooling oil switching. The supply device 5 is provided.

In the double cylinder 2, a piston rod 9a of a piston 9 provided in the cylinder 8 is formed into a cylinder shape, and a central rod 10 standing on an inner wall surface of the lower end of the cylinder 8 is vertically movable in the piston rod 9a. It has been fitted. The upper end of the piston rod 9a is hermetically sealed with a cover plate 11, and the space inside the piston rod 9a serves as a small diameter oil chamber A1. The upper space partitioned by the piston 9 in the cylinder 8 becomes the return side oil chamber A2, and the lower space becomes the large diameter oil chamber A3. Reference characters a1 to a3 denote ports of the oil chambers A1 to A3.

The double cylinder 2 is installed so that the punch metal fitting 1 is fixed to the cylinder 8 so that the cylinder 8 side moves up and down. That is, the upper end of the piston rod 9a is fixed to the frame 12, and the cylinder 8 is installed in the guide cylinder 13 provided in the frame 12 so as to be able to move up and down. The guide cylinder 13 has detection switches SWU and SW for detecting that the cylinder 8 is at a top dead center, a bottom dead center, and an intermediate point, respectively.
D and SWM are provided. Each switch SWU, SWD,
The SWM is composed of a normally closed proximity switch or the like, and detects a predetermined position of each cylinder 8 and turns on.

The hydraulic pressure supply system 3 for driving the cylinder will be described. The discharge pipe 20 of the pump P1 has two paths 20a,
20b, and the first branch path 20a is switchably connected to the return side oil chamber A2 and the large diameter oil chamber A3 of the double cylinder 2 via the first switching valve V1. Second branch path 2
0b is switchably connected to the small diameter oil chamber A1 and the return side oil chamber A2 of the double cylinder 2 via the second switching valve V2. Each of the switching valves V1 and V2 is an electromagnetic switching valve at the 4 port 3 position, and the return oil side port T is the tank 2
1, 22. In the figure, 23 and 24 are check valves, 25 is an accumulator, 26 to 28 are check valves with an external pilot, and 29 is a throttle valve.

The cooling oil supply system 4 is an oil supply system for returning the discharge pipe 30 of the pump P2 to the tank 32 via the cooled portion 34. The cooled portion 34 is a portion of the press machine that needs to be cooled, for example, a hydraulic clutch / interval for intermittently operating the press.
A brake, a cooling coil and a cooling jacket along the inner surface of the frame, a cooling path for each actuator and a bearing portion, and the like.

The cooling oil switching supply device 5 includes a cooling oil supply system 4
The path 30a branched from the discharge pipe 30 of
Also, it is connected to the large-diameter oil chamber A3 of the double cylinder 2 via the check valve 33. Open / close valve V3 is 2 port 2
Position solenoid valve.

FIG. 2 is a plan view showing an example of the overall structure of a hydraulic press having the double cylinder 2 installed therein. This hydraulic press is composed of a turret punch press, and has a main head 42 that punch-drives a mold installed on a turret 41,
A sub head 43 dedicated to cutting off the joint portion of the processed work is provided, and the double cylinder 2 of FIG. 1 is adopted as the sub head 43. The main head 41 is driven by a crank type punch drive mechanism (not shown). The work table device 44 holds the work W placed on the upper surface with the work holder 45 and moves the work W forward, backward, leftward and rightward.

The operation of the above configuration will be described. Punch mold 1
Pump P1 when lowering from the top dead center to the middle point.
Supplies high pressure oil to the small diameter oil chamber A1. Since the small-diameter oil chamber A1 has a small cross-sectional area, the cylinder 8 descends at a high speed by the supply of this pressure oil. At this time, the large diameter oil chamber A3
Since the capacity gradually increases, the pressure becomes negative as it is, but the low pressure cooling oil of the cooling oil supply system 4 is supplied from the pump P2, and the negative pressure is prevented.

After passing the intermediate point, the valves V2 and V3 are switched to the pump P for both the small diameter oil chamber A1 and the large diameter oil chamber A3.
The high-pressure pressure oil discharged from No. 1 is supplied. As a result, the stroke speed is reduced, but a large pressing force required for the press can be obtained. When the bottom dead center is reached, the high pressure oil of the pump P1 is supplied to the return side oil chamber A2, and the cylinder 8
Raise.

In this hydraulic press, the small-diameter oil chamber A is thus
1 and a double cylinder 2 having a large oil chamber A3,
During the descending operation from the top dead center to the middle point where the pressing load does not act, the pressure oil is supplied to the small diameter oil chamber A1 and the large diameter oil chamber A3.
Since it is operated by supplying cooling oil to the pump, a high stroke speed can be obtained with the small-capacity pump P1, and productivity can be improved. Further, since the cooling oil supply system 4 is used as the hydraulic oil supply system to the large diameter oil chamber A3 during high speed operation,
It is only necessary to add the cooling oil switching / supplying device 5 composed of the on-off valve 3 and piping, and unlike the case where a dedicated hydraulic pressure source is provided to the large diameter oil chamber A3, the configuration of the hydraulic system is simple.

FIG. 3 shows another embodiment. In this example, on the upper side of the piston 51, a small-diameter oil chamber A1 and a large-diameter oil chamber A3 are provided in the cylinder 52, and a return-side oil chamber A2 is provided on the lower side to configure the double cylinder 50. In this case, the die 1 is attached to the piston 51, and the piston 51 is used as the movable side. In each oil chamber A1 to A3, the pressure oil supply system 3 and the cooling oil supply system 4 of FIG.
And the cooling oil switching supply device 5 is connected. Also in the case of such a configuration, the stroke speed can be improved by the hydraulic system having the same simple configuration as in the above embodiment.

In each of the above embodiments, the double cylinders 2 and 50 are used to drive the die 1 on the punch side. However, in the present invention, the double cylinders 2 and 2 are used to drive the die on the die side.
The present invention can be applied to a punch press provided with 50, and also to various hydraulic presses other than the punch press.

[0020]

The hydraulic press of the present invention uses a double cylinder having a small diameter oil chamber and a large diameter oil chamber, and connects the cooling oil supply system to the large diameter oil chamber by switching the pressure oil supply system. Since the cooling oil switching supply device is provided, it is possible to increase the stroke speed when there is no load by supplying hydraulic pressure to the small diameter oil chamber, and at the same time, use cooling oil to prevent negative pressure from being generated in the large diameter oil chamber. Therefore, it is possible to increase the stroke speed and improve the productivity with a hydraulic system having a simple structure.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a cross section of a double cylinder and a hydraulic circuit in an embodiment of the present invention.

FIG. 2 is a plan view of the entire hydraulic press.

FIG. 3 is a cross-sectional view of a double cylinder according to another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Punch die, 2 ... Double cylinder, 3 ... Pressure oil supply system, 4 ... Cooling oil supply system, 5 ... Cooling oil switching supply device, 8 ...
Cylinder, 9 ... Piston, 9a ... Piston rod, 10
... center rod, 12 ... frame, 13 ... guide tube, 50
... Double cylinder, P1, P2 ... Pump, V1, V2 ... Switching valve, V3 ... Open / close valve

Claims (1)

[Claims] 1. A double cylinder having a small-diameter oil chamber and a large-diameter oil chamber for applying a hydraulic pressure in the positive direction between a piston and a cylinder, and a return-side oil chamber for applying a hydraulic pressure in the opposite direction is used for a mold lifting mechanism. A hydraulic press having a cooling oil switching supply device that connects the cooling oil supply system to the large-diameter oil chamber by switching to the pressure oil supply system.