JP2576048B2 - Hydraulic press device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic press apparatus, and more particularly to a hydraulic press apparatus having a stroke limiting device capable of precisely defining a rising end position and a falling end position of a piston.

[0002]

2. Description of the Related Art There is a method of controlling the raising and lowering of a piston in a hydraulic press using a solenoid valve. FIG. 5 shows an example of a hydraulic circuit of a hydraulic press device using a solenoid valve. In the figure, 1 is a hydraulic cylinder, 2
The ram, 3 is a solenoid valve, 4 is a hydraulic source, 5 is a tank, and the driving direction of the piston 6 of the hydraulic cylinder 1 is controlled by switching the hydraulic pressure from the hydraulic source 4 by the solenoid valve 3.

In order to lower the piston 6, the solenoid 13 on the right side in FIG. 5 is excited to switch from the valve pattern of all port blocks at the neutral position to the valve pattern on the right side in the figure. Make the port communicate with the A port. As a result, pressure oil is supplied from the hydraulic pressure source 4 to the cap-side liquid chamber 8 of the hydraulic cylinder 1, the hydraulic oil in the head-side liquid chamber 9 is discharged to the tank 5, and the piston 6 descends. Then, a downward force is transmitted from the ram 2 to a mold (not shown), and press working is performed.

When the bottom dead center accuracy of the piston 6 is required,
The contact between the dog 10 provided at the right end of the ram 2 and the lower mechanical end stopper 11 is used. That is, when the lowering of the piston 6 is stopped by the dog 10 hitting the mechanical end stopper 11, the pressure in the cap-side liquid chamber 8 increases. This is detected by a pressure sensor or the like, the excitation of the right solenoid 13 is stopped, and the lowering is stopped. Let it. However, normally, the lower end proximity switch 1 is located above the mechanical end stopper 11.
2, the excitation of the left solenoid 7 is stopped when the lower end proximity switch 12 detects the dog 10, and the lowering is terminated.

In order to raise the piston 6, the solenoid 13 on the right side in the figure is excited to switch the valve pattern between the P port and the A port and the T port and the B port. Thus, pressure oil is supplied from the hydraulic pressure source 4 to the head-side liquid chamber 9, and the hydraulic oil in the cap-side liquid chamber 8 is supplied to the tank 5.
And the piston 6 rises. The stop of the rise of the piston 6 is performed by turning off the excitation of the right solenoid 13 when the rising end proximity switch 14 detects the dog 10. In the figure, reference numeral 15 denotes an upper mechanical end stopper, and a stroke of the piston 6 is between the two mechanical end stoppers 11 and 15.

[0006]

By the way, the solenoid valve used in the hydraulic press device which performs high-speed operation is designed with a spring force or the like so that high-speed switching is possible, but a delay of about 20 milliseconds occurs at the time of switching. Further, a variation of about 10 milliseconds occurs due to a timing problem of the controller. That is, until the piston is stopped by a signal from the proximity switch, it takes at least 20 milliseconds and at most 3
A time of 0 millisecond is required.

[0007] Such a time is not a problem in a normal hydraulic press.
In a hydraulic press device for high-speed operation, in which a 10 mm stroke is performed about 5 to 8 times per second at a rising speed of 500 mm / sec and press working is performed at a speed of 500 mm / sec, the above-described delay is unacceptable. With such a delay, 2-3 mm at the end of descending, and 10 to 15 mm at the end of ascending.
The piston is moved, and the amount of excessive movement is 12 to 18 mm with respect to the originally desired movement section of 10 mm.
, Which leads to a lot of useless movements and poor efficiency. If the amount of overshoot is stable, a stop command may be issued in anticipation of the amount of overshoot, but in reality the variation is large (6 m in the above calculation).
m) In addition, considering that the load varies, it was not possible to suppress useless movement to 10 mm or less, and it was necessary to move 20 mm where 10 mm had to be moved, and the efficiency was halved. .

[0008] Such a problem can be solved by using a servo valve. Although the basic hydraulic circuit of a device using a servo valve does not change much, it moves while constantly calculating the current position of the piston by calculating the amount of discharged oil, so it can be accurately stopped at a predetermined position. it can. That is, when a servo valve is used, the feedback of the position is applied and it is always known how much it should move. Therefore, the servo valve can be decelerated slightly before the stop position and stopped at the desired position with high accuracy. And high speed operation becomes possible. However, the servo valve is an expensive device, and it is difficult to adopt the servo valve in most hydraulic presses in terms of cost.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide an inexpensive, high-speed hydraulic press device that realizes the same lean movement as a servo valve using a solenoid valve. And

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, a hydraulic press device according to the present invention has a locking projection provided on a piston for driving a mold up and down, and is capable of engaging with and disengaging from the projection. And a means for driving the stopper in a direction to move the stopper toward and away from the piston. The end position can be defined.

In the hydraulic press apparatus according to the present invention, the driving means is a pneumatic or hydraulic cylinder, and the stopper is replaceably attached to a rod end of the pneumatic or hydraulic cylinder so as to be movable forward and backward. It can be configured.

In the hydraulic press device according to the present invention, the driving means is a rotary driving means, and the stopper is replaceably attached to an output shaft end of the rotary driving means so that the stopper is disposed in a direction orthogonal to the axial direction of the piston. It can be configured to be rotatable.

[0013] The hydraulic press device according to the present invention may have a configuration in which a plurality of the stoppers are provided and automatic selection can be made in accordance with the rising end position and the falling end position of the piston to be defined.

The hydraulic press device according to the present invention may have a structure in which a portion is provided above the stopper to hold the piston below the protrusion at the upper limit locking position of the piston.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a side view of a hydraulic press device using a C-shaped frame according to one embodiment of the present invention, FIG. 2 is an enlarged sectional view taken along line 3-3 in FIG. 1, and FIG. 3 is a stroke of the device in FIG. It is a top view which expands and shows the principal part of a limiting device.

The illustrated hydraulic press device has substantially the same configuration as a known device. A cylinder tube 21 is mounted on a frame 20, a piston 22 is slidably disposed on the inner surface of the cylinder tube 21, and mounted on a tip of the piston 22. When the ram 23 is guided by the guide bush 24 and is accurately driven up and down, a mold 26 provided between the ram 23 and the bolster 25 performs press working.

In the figure, reference numeral 30 denotes a stroke limiting device, which includes a ring 31 fixed to the piston 22 and a stopper 32.
And an air cylinder 33. Air cylinder 3
3 is mounted on a support bracket 35 attached to the tip of a protrusion 34 of the frame 20 provided with the guide bush 24. The support bracket 35 has proximity switches 37 and 38 for detecting a dog 36 protruding from the ram 23.
Is attached via a bracket 39.

The stopper 32 is exchangeably attached to the end of a rod of an air cylinder 33 which is a driving source enabling automatic exchange. The stopper 32 has a box shape with the ring 31 side opened, and has a U-shaped cutout of the upper surface portion 40 and the cutout surface portion 41, and a fitting port 42 for the piston 22.
And cushions 43 and 44 made of urethane or the like are attached to the lower surface side of the upper surface portion 40 and the upper surface side of the lower surface portion 41,
The impact caused by the contact with the ring 31 can be reduced. The cushions 43 and 44 have U-shaped cutouts on the piston 22 side as well as the upper surface portion 40 and the lower surface portion 41. Further, a notch 45 for fitting to the ring 31 having a larger diameter than the fitting port 42 is provided on the upper surface of the upper surface portion 40 to form an upper limit locking mechanism of the piston 22.

The stopper 32 restricts the movement of the ring 31. The stopper 32 is effective when the air cylinder 33 is extended, and invalid when the air cylinder 33 is contracted. The dotted line state in FIG. 3 shows the stopper invalid state, and the solid line states in FIGS. 2 and 3 show the ring 31 upper limit lock state and the stopper valid state.

The proximity switches 37 at the rising end and the falling end
The dog 38 and the dog 36 perform the same operation as the conventional proximity switches 12, 14 and the dog 10 shown in FIG. The hydraulic circuit is also the same as the circuit in FIG. 2. Although not shown, pressure oil from a hydraulic line is supplied to a liquid chamber 46 on the cylinder tube side or a liquid chamber 47 on the head side by a solenoid valve. , 47 to the tank to discharge hydraulic oil.

Next, the operation of this embodiment will be described. First, the air cylinder 33 is extended as shown by a solid line in FIGS. 2 and 3, and the stopper 32 is set in an effective state. In this state, hydraulic pressure is supplied in the same manner as in the related art, and when the piston 22 descends and the lower proximity switch 38 detects the dog 36, the excitation of the solenoid valve is stopped immediately. Hits the lower cushion 44 and stops. In practice, immediately after the proximity switch 38 detects, the ring 31 hits the cushion 44, and
The cushion 44 is deformed by about mm and stopped. On the other hand, when the piston 22 rises, the upper proximity switch 37
Senses the dog 36. Immediately, the excitation of the solenoid valve stops, and immediately thereafter, the upper surface of the ring 31 hits the upper cushion 43 and stops. At this time, the cushion 43 is deformed by about 0.5 mm. For this reason, the upper surface portion 40
Stopping with good positional accuracy can be performed by selecting and replacing the stopper 32 in which the interval between the lower surface 41 and the thickness of the cushions 43 and 44 correspond to the moving distance of the piston 22. When replacing the stopper 32, it goes without saying that the rod of the air cylinder 33 is contracted to perform the operation.

It should be noted that the ring 31 has cushions 43 and 44.
, The impact force is reduced.
High rigidity is required because a static pressing force is applied for a period of 0 to 30 milliseconds. However, since only a compressive force is applied to the stopper 32, there is little strength problem and cost increases. Don't worry.

The stopper invalid state is used when performing operations such as mold replacement and long stroke machining. Of course, even without this stopper, the operation of the hydraulic press device is the same as that of the conventional device. It can be used during trials. For example, when applying to a turret punch press or the like, when using a mold that is processed only once or twice, do not use the above-described stroke limiting device, and
It can be used only when processing with the same mold more than once.

Further, in a normal hydraulic press, the piston 22 is raised to the uppermost position and the stopper 3
2, the frame 31, the piston 22, and the ram 23 are integrated with the ring 31 supported by the notch 45. This can prevent the ram 23 from falling under its own weight and damaging the operator.

FIG. 4 is a sectional view of a second embodiment of the present invention near the ring 31 as viewed from above. In this embodiment, the drive source of the stopper 32 is the motor 50, a plurality of the stoppers 32 are attached around the arm 51 attached to the output shaft of the motor 50, and the arm 51 is rotated to make the stopper invalid state and the stopper invalid. The effective state is switched. In the illustrated example, the optimal one of the two types of stoppers 32 can be selected in the rotation direction of the motor 50. The stopper 32 of this embodiment has a tapered portion 52 at a part of the fitting opening 42 to avoid interference during rotation. Others are the same as the previous embodiment. In this embodiment, the driving source of the stopper 32 is a motor, but a hydraulic or pneumatic rotary actuator may be used instead.

[0026]

The hydraulic press apparatus according to the present invention can accurately determine the positions of the ascending and descending ends of the piston with a mechanical stroke limiting device even at the time of high-speed operation, and is an expensive device such as a servo valve. There is an effect that the equipment cost can be reduced without using the device. In addition, since there is no useless movement, the energy that can be used effectively increases, the operating cost is reduced, and a simple structure that can be attached later to the hydraulic press device that is currently operating can be provided. Compared to a system using a servo valve, there is also an effect that the number of parts causing a failure is small and maintenance is easy.

The hydraulic press device according to the fourth aspect has an effect that the stopper can be easily replaced in accordance with a desired piston stroke in addition to the above-mentioned common effect.

The hydraulic press device according to the fifth aspect has the effect that, in addition to the above-mentioned common effects, the piston can be held at the upper limit lock position at the time of mold replacement or the like, so that work safety can be achieved. .

[Brief description of the drawings]

FIG. 1 is a side view of a first embodiment of a hydraulic press device according to the present invention.

FIG. 2 is an enlarged sectional view taken along line 3-3 in FIG.

FIG. 3 is an enlarged sectional view of a main part of the apparatus of FIG. 1;

FIG. 4 is a sectional view corresponding to FIG. 3 of a second embodiment of the present invention.

FIG. 5 is a hydraulic circuit showing a typical hydraulic circuit example of a hydraulic press device.

[Explanation of symbols]

 Reference Signs List 20 Frame 21 Cylinder tube 22 Piston 23 Ram 25 Bolster 26 Die 30 Stroke limiter 31 Ring 32 Stopper 33 Air cylinder 36 Dog 37, 38 Proximity switch 42 Fitting opening 43, 44 Cushion 45 Cut 45 46 Cylinder tube side liquid chamber 47 Head Side liquid chamber 50 mode 52 taper section

Claims (5)

(57) [Claims] 1. A locking projection provided on a piston for driving a mold up and down, a stopper capable of engaging with and disengaging from the projection, and means for driving the stopper in a direction to move toward and away from the piston. A hydraulic press device comprising a stroke limiting device comprising: a stopper configured to lock the protruding portion with the stopper to define a rising end position and a falling end position of the piston. 2. The apparatus according to claim 1, wherein said driving means is a pneumatic or hydraulic cylinder, and said stopper is replaceably attached to a rod end of said pneumatic or hydraulic cylinder so as to be movable forward and backward. Hydraulic press equipment. 3. The device according to claim 2, wherein the drive means is a rotary drive means, and the stopper is replaceably attached to an output shaft end of the rotary drive means so as to be rotatable in a direction orthogonal to the axial direction of the piston. 2. The hydraulic press according to claim 1, wherein: 4. The hydraulic press apparatus according to claim 3, wherein said piston has a plurality of stoppers, and can be automatically selected according to a rising end position and a falling end position of said piston to be defined. 5. The hydraulic press according to claim 1, wherein a portion is provided above the stopper to hold the piston below the protrusion at an upper limit locking position of the piston.