JPH0857700A - Hydraulic pressing apparatus - Google Patents

Abstract

PURPOSE: To provide a hydraulic pressing apparatus which realizes the movement without waste, as the same way as a servo valve by using a solenoid valve in a low cost and can operate in high speed. CONSTITUTION: This hydraulic pressing apparatus is provided with a stroke limiting device composed of a ring 31 fixed to a piston 22 for driving a die upward/downward, a stopper 32 possible to engage/disengage with the ring 31 and an air cylinder 33 for driving the stopper 32 in the direction attached/ detached to the piston 22. The fitting hole 42 of the stopper 32 is fitted with the outer periphery of an air cylinder 22, and the ascending end position and descending end position of the piston 22 are regulated by hitting the cushion 43 against the ring 31 at the time of ascending with the air cylinder 33.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art A solenoid valve is used as a method of controlling the ascent and descent of a piston of a hydraulic press machine. 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
Is a 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 with 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 is provided, and when the descending end proximity switch 12 senses the dog 10, the excitation of the left solenoid 7 is stopped and the descending is completed.

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 ascending end of the piston 6 is stopped by turning off the excitation of the right solenoid 13 when the ascending 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, a solenoid valve used in a hydraulic press device which operates at high speed is designed with a spring force or the like so that it can be switched at high speed, 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 descent and 10-15 mm at the end of ascent.
As the piston moves, the overtravel amount is 12 to 18 mm with respect to the originally desired travel section of 10 mm.
This is because there are many useless movements and the efficiency becomes poor. If the amount of overshoot is stable, it is sufficient to anticipate the amount of overshoot and issue a stop command before that, but in reality, there are large variations (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 device according to the present invention, the driving means is a pneumatic or hydraulic cylinder, and the stopper is replaceably attached to the rod end of the pneumatic or hydraulic cylinder so as to be movable back and forth. It can be configured.

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

The hydraulic press device according to the present invention may be configured to have a plurality of the stoppers, and to automatically select according to the ascending end position and the descending end position of the piston to be defined.

In the hydraulic press device according to the present invention, a portion for holding the lower portion of the protrusion at the upper limit lock position of the piston may be provided on the upper portion of the stopper.

[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 an embodiment of the present invention, FIG. 2 is an enlarged sectional view taken along line 3-3 of FIG. 1, and FIG. 3 is a stroke of the device of 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 structure as a known device, in which a cylinder tube 21 is attached to a frame 20, a piston 22 is slidably arranged on the inner surface thereof, and the piston 22 is attached to the tip of the piston 22. When the ram 23 is guided by the guide bush 24 and is accurately moved up and down, the die 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 the protrusion 34 of the frame 20 provided with the guide bush 24, and the support bracket 35 has proximity switches 37, 38 for detecting the dog 36 protruding from the ram 23.
Is attached via a bracket 39.

The stopper 32 is replaceably attached to the end of an air cylinder 33 rod which is a drive 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 shock caused by the contact with the ring 31 can be alleviated. 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 the same as that of FIG. 2 circuit, and although not shown, pressure oil from the hydraulic line is supplied to the liquid chamber 46 on the cylinder tube side or the liquid chamber 47 on the head side by a solenoid valve, and both liquid chambers 46 , 47 to the tank to discharge the hydraulic oil.

Next, the operation of the apparatus of this embodiment will be described. First, the air cylinder 33 is extended as shown by the solid lines in FIGS. 2 and 3 to keep the stopper 32 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 moves up, the upper proximity switch 37
Detects 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. Also at this time, the cushion 43 is deformed by about 0.5 mm. Therefore, 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 static pressure is applied for 0 to 30 ms, but since the stopper 32 applies only compressive force, there are few strength problems and cost increases. I don't have to 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 machining with the same die 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 by 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, and a plurality of stoppers 32 are attached around the arm 51 attached to the output shaft of the motor 50, and the arm 51 is rotated so that the stopper is in the invalid state and the stopper. The valid 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 those in 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]

EFFECTS OF THE INVENTION The hydraulic press device according to the present invention is capable of accurately defining the ascending end position and the descending end position of the piston by a mechanical stroke limiting device even during 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. Also, since it does not uselessly move, the energy that can be used effectively increases, the operating cost becomes lower, and it is possible to have a simple structure that can be attached later even to the hydraulic press device currently in operation. Compared to a system that uses a servo valve, there are fewer parts that cause failures, and maintenance is easier.

In addition to the above-mentioned common effects, the hydraulic press device according to the fourth aspect has an effect that the stopper can be easily replaced according to a desired stroke of the piston.

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 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 cross-sectional view of a main part of the device shown in FIG.

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]

 20 Frame 21 Cylinder Tube 22 Piston 23 Ram 25 Bolster 26 Mold 30 Stroke Limiting Device 31 Ring 32 Stopper 33 Air Cylinder 36 Dog 37, 38 Proximity Switch 42 Fitting Port 43, 44 Cushion 45 Notch 46 Cylinder Tube Side Liquid Chamber 47 Head Side liquid chamber 50 Mortei 52 Tapered part

Claims (5)

[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 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 an axial direction of the piston. The hydraulic press device according to claim 1. 4. The hydraulic press device according to claim 3, wherein a plurality of the stoppers are provided, and the stoppers can be automatically selected according to an ascending end position and a descending end position of the piston to be regulated. 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.