JPH01293998A - Counter balance device for machine press - Google Patents

Abstract

PURPOSE:To improve the accuracy of a product and the quality by employing a hydraulic cylinder as a counter balance cylinder and correcting horizontally by the command of an arithmetic control unit by detecting by position detector in case of a slide being inclined. CONSTITUTION:At the time when a slide 2 is not inclined a change valve 33 is communicated by the command of a control device 53 and a servovalve 39 is cut off. The oil pressure of an accumulator 34 acts on the oil chamber 18 of a counter balance cylinder 16, a rod 15 is energized upward, the weights of the slide and upper die are offset and the lift of the slide is performed in the state of no clearance of a press bearing part, etc. At the time when the slide is inclined to the right downward the charge valve 33 is cut off by a command, the servovalve 39 is communicated, the oil pressure of the accumulator 38 acts on a cylinder 40, pistons 44, 43 are pressed, the oil pressure of an oil chamber 47 acts as a restoring force on the oil chamber 18' of the cylinder 16 and adjusts so that the slide 2 becomes horizontal. The upper die is thus maintained and the accuracy of a product can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a counterbalance device for a mechanical press.

[Prior Art] An example of a commonly used mechanical press will be explained with reference to FIGS. 2 and 3. A slide 2 is provided inside the housing 1 so as to be movable up and down, and a slide 2 for driving the slide 2 up and down is installed on the top of the housing 1. An eccentric shaft 3 is rotatably supported by a bearing 4,
A gear 5 is fixed to one end of the eccentric shaft 3, and a gear 9, which is connected to the electric motor 6 via a coupling 7 and a clutch 8 to transmit the driving force of the electric motor 6, is meshed with the gear 5. A connecting rod 11 is pivotally attached to the eccentric part 10, and the lower end of the connecting ink mouth 11 is connected to the slide 2 so that the slide 2 can be driven up and down.

The upper mold 12 is exchangeably held on the lower surface of the slide 2, and the lower mold 13 is exchangeably held in the lower part of the housing 1 so as to face the upper mold 12, and the position of the upper mold 12 is detected. A position detector 14 such as a rotary encoder is attached to the other end of the eccentric shaft 3.

Air cylinder type counterbalance cylinders 16 are connected to both sides of the housing 1, with the rod 15 facing downward (on the contrary, the rod 15 may be facing upward).
The rods 15 of the counterbalance cylinders 16 are each fixed to mounting members 17 on the sides of the slide 2.

Note that 25 is a material, and 26 is a power supply device that supplies power to the electric motor 6.

When operating a mechanical press, turn on the power supply to operate the electric motor 6, then turn on the clutch 8 to rotate the gear 9, and the rotation of the gear 9 is transmitted to the eccentric shaft 3 via the gear 5. The connecting rod 11 is moved up and down, and the slide 2 is moved up and down by the up and down movement of the connecting rod 11, and the upper mold 12 is moved toward and away from the lower mold 13, and the material is molded between them.

During molding, the weight of the slide 2 and the upper mold 12 is canceled out by the push-up blade of the counterbalance cylinder 16, and the clearance of the many bearings and pin joints provided in the press ensures the accuracy of the molded product. During press operation, the counterbalance cylinder 16 is actuated in the direction in which the rod contracts to urge the slide 2 upward, thereby canceling out the weight and eliminating the clearance.

The conventional counterbalance device used in the above-mentioned mechanical press has a counterbalance cylinder 16 as shown in FIG.
The air from the compressor 19 can be supplied to the rod-side air chamber 18 from the upstream side through a passage 24 that includes a check valve 20, a pressure reducing valve 21, a check valve 22, and a tank 23. By setting the pressure of the air to be supplied to the rod side air chamber 18 using the pressure reducing valve 21, the pressure of the air to be supplied to the rod side air chamber 18 is set using the pressure reducing valve 21, and the tank 23 and the counterbalance cylinder are A compressor 19 is installed in the air chamber 18 on the rod side of 16.
During the press operation, the slide 2 is constantly urged upward by the counterbalance cylinder 16 to cancel out the weight of the slide 2 and the upper die 12, and to eliminate press clearance.

[Problems to be Solved by the Invention] However, since the above-mentioned counterbalance device uses an air cylinder as the counterbalance cylinder 16, the cylinder itself becomes large and the pressure in the air chamber 18 of the counterbalance cylinder 1G increases. In order to reduce fluctuations, the capacity of the tank 23 must also be increased, which means that the entire mechanical press becomes larger and the upper mold 1
When the slide 2 is subjected to an eccentric load, the slide 2 tilts, but since the counterbalance device described above cannot correct the tilt of the slide 2, there are problems such as a decrease in the precision of the molded product.

The present invention has been made in view of the above-mentioned circumstances with the aim of downsizing the device and improving product quality.

[Means for Solving the Problems] The present invention provides a rod-side oil chamber and a first hydraulic pressure of a hydraulic cylinder-type counterbalance cylinder for upwardly biasing a liftable slide to which an upper mold is attached. The first accumulator is connected to a conduit connecting the source through a switching valve, and has two pistons arranged in series so that they can move together, and is partitioned between the two pistons, and each piston A pressure control cylinder with an oil chamber is installed before and after the
A rod-side oil chamber of the counterbalance cylinder is communicated with one of the hydraulic chambers formed before and after one piston of the pressure control cylinder, and the other pressure control cylinder having the two pistons is connected to the rod side oil chamber of the counterbalance cylinder. A control valve is provided in a conduit connecting the oil chamber formed before and after the piston and the second hydraulic pressure source,
an arithmetic and control device that connects a second accumulator between the second hydraulic pressure source and the control valve, receives a signal from a detector that detects the inclination of the slide, and outputs a command signal to the switching valve and the control valve; It has a configuration with

[Operation] If the slide is not tilted, the control valve is shut off and
The switching valve is switched so that the first accumulator communicates with the counterbalance cylinder rod side oil chamber, and the first accumulator cancels out the weight of the slide and upper die, and also reduces the clearance between the press bearing and the pin pivot point. If the slide and the upper mold are raised and lowered in a state where there is no The accumulator and the oil chamber on the head side of the other piston of the pressure control cylinder are switched to communicate with each other, and the two pistons of the pressure control cylinder are moved by the oil pressure of the second accumulator, so that the oil pressure is transferred to the counterbalance cylinder. The roller 7 = 1 acts on the side oil chamber, causing the downward side of the slide to rise and the slide to return to its horizontal state.

[Example] Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows one embodiment of the present invention, in which the mechanical press itself has a second
The configuration is similar to that shown in FIG. 3 and FIG.

To explain the counterbalance device, the counterbalance cylinders 16 disposed on both sides of the housing 1 are of a hydraulic cylinder type, and a hydraulic pump (first hydraulic power source) that sucks oil from an oil tank 27, pressurizes it, and discharges it. One end of a pipe line 29 is connected to the discharge side of the cylinder 28, a switching valve 30 is connected to the other end of the pipe line 29, and the other end of the pipe line 31, which has one end connected to the switching valve 30, is connected to the counter balance cylinder 16.
The switching valve 3 is connected to the oil chamber 18° in the middle of the pipe line 31.
3 is connected to one end of the conduit 32, and a first accumulator 34 is connected to the other end of the conduit 32.

One end of the pipe line 36 is connected to the discharge side of a hydraulic pump (second hydraulic pressure source) 35 that sucks oil from the oil tank 27, pressurizes it, and discharges it. A second accumulator 38 is connected, a switching valve 54 is connected to the middle part of the conduit 36 upstream of the connection part of the conduit 37, and a servo valve 39 is connected to the other end of the conduit 36.

Cylinder 41 arranged in series of cylinder 40 for pressure control
．． A partition plate 45 is fixed between the cylinders 41 and 42.
The pistons 43 and 44 are slidably fitted into the cylinders 4 through the partition plate 45.
1. ．． The oil chamber 47 is fixed to both ends of the rod 46 extending into the cylinder 42, and an oil chamber 47 is formed on the piston head side of the cylinder 41.
The cylinder 42 is formed with an oil chamber 48a on the piston head side and an oil chamber 48b on the rod side.The oil chamber 47 is connected to the other end of a pipe 49 whose one end is connected to the pipe 31, and the oil The chambers 48a, 48b are connected to the other ends of conduits 50, 51, one end of which is connected to the servo valve 39.

Position detectors 52 and 52' for detecting the same upper and lower positions of the slide 2 are disposed on both sides of the slide 2, respectively.
The signal detected at 2.52° is sent to the arithmetic and control unit 53,
It is possible to give commands to the switching valve 33 and the servo valve 39 from the arithmetic and control device 53. A stroke sensor or an angle sensor is used as the position detector 52, 52'.

In the figure, 55 is a conduit for returning to the ura, and 56 is a safety valve.

During operation, pressure is accumulated in the accumulator 34.38 by the hydraulic pump 28.35, and the switching valve 30.5
4 is cut off as shown in FIG. 1 to perform the work.

When the slide 2 is not tilted, the switching valve 33 is opened and the servo valve 39 is closed, as shown in FIG. Therefore, the hydraulic pressure accumulated in the accumulator 34 acts on the oil chamber 18° of the counterbalance cylinder 16 via the pipe line 32, the switching valve 33, and the pipe line 32.31, and the rod 15
is biased upward. Therefore, the weight of the slide 2 and the upper mold 12 is canceled out by the upward force of the counterbalanced link 16, and the slide 2 And the upper mold 12 is raised and lowered.

When the slide 2 and the upper mold 12 are raised and lowered, the position detector 5
2,52°, the left and right positions of the slide 2 are continuously detected and the signals are sent to the arithmetic and control unit 53, where the deviation of the signals from the position detectors 52 and 52 is determined. From the sign of the deviation, it can be determined whether the slide 2 is tilted to the left or right. Note that the oil pressure of the accumulator 34 is applied to the oil chamber 18 of the counterbalance cylinder 16.
', the oil pressure of the accumulator 34 also acts on the oil chamber 47, but the pipes 50 and 51 are connected to the servo valve 39.
The pistons 43, 44 and rod 46 of the pressure control cylinder 40 do not move because they are in a sealed state.

1 If an eccentric load acts on the mold I2 and the slide 2 is tilted so that the right side is down and the left side is up as shown in FIG. The switching valve 33 and the servo valve 39 on the right shown are turned off, and the servo valve 39 is switched so that the pipes 36 and 50 are in communication and the pipes 51 and 55 are in communication. .

Therefore, the hydraulic pressure accumulated in the accumulator 38 acts on the oil chamber 48a of the pressure control cylinder 40 via the pipe 37.3B, the servo valve 39, and the pipe 50, and the piston 4
Push 4 towards the right in Figure 1. Therefore, the rod 46 and the piston 43 are also pushed to the right in FIG. Adjustment is made by raising the right side of slide 2 so that slide 2 is horizontal. When the inclination of the slide 2 is within the target value, the switching valve 33 is opened and the servo valve 39 is opened in response to a command from the arithmetic and control unit 53.
or shut off and return to normal operation.

As mentioned above, as the counterbalance cylinder 16,
By using a hydraulic cylinder, the counterbalance cylinder 16 becomes smaller and a large capacity tank is not required, so the entire device becomes compact, and even when an eccentric load is applied, the slide 2 and the upper mold 12 Because it can be restored to its original state, it is possible to obtain highly accurate products. In addition, the pressure that has passed through the servo valve 39 is sent directly to the oil chamber 18 of the counterbalance cylinder 16. Since it acts on the oil chamber 18° of the balance cylinder 16, the oil controlled by the servo valve 39 is less likely to be contaminated, and therefore the oil can be easily managed.

It should be noted that the present invention is not limited to the above-described embodiments, and that the switching valve provided near the hydraulic pump may be a check valve, and that various control valves other than servo valves can be used. It goes without saying that various changes may be made without departing from the spirit of the invention.

[Effects of the Invention] According to the counterbalance device for a mechanical press of the present invention,
Since a pressure cylinder is used as the counterbalance cylinder, the counterbalance cylinder can be made smaller and a large-capacity tank is not required. This allows the entire device to be made more compact, and it can also be used to level the device if it slides or tilts. Since the upper mold can be maintained horizontally, the precision of the molded product is improved and the quality is good.Furthermore, the pressure passing through the control valve does not act directly on the counterbalance cylinder. , the oil controlled by the control valve is free from contamination, and therefore oil management becomes easier, and various other excellent effects can be achieved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of a counterbalance device for a mechanical press according to the present invention, FIG. 2 is a general explanatory diagram of a mechanical press, and FIG. FIG. 4 is an explanatory diagram of an example of a conventional counterbalance device for a mechanical press. In the figure, 2 is a slide, 12 is an upper mold, 16 is a counterbalance cylinder, 18゛ is an oil chamber, 28 is a hydraulic pump, 29
．． 31 is a pipe line, 33 is a switching valve, 34 is an accumulator,
35 is a hydraulic pump, 36 is a pipe line, 39 is a servo valve, 38
40 is an accumulator, 40 is a syringe for pressure control, 43.
44 is a piston, 46 is a rod, 47° 48a, 48b
indicates the oil chamber.

Claims (1)

[Claims] 1) A switch valve is connected to a pipe line connecting the rod-side oil chamber of a hydraulic counterbalance cylinder for upwardly urging the liftable slide to which the upper mold is attached and the first hydraulic power source. A pressure control cylinder having two pistons arranged in series connected to one accumulator so that they can move integrally, partitioned between the two pistons, and forming an oil chamber at the front and rear of each piston. The rod-side oil chamber of the counterbalance cylinder is communicated with one of the hydraulic chambers formed before and after one piston of the pressure control cylinder, and the pressure control cylinder having the two pistons is A control valve is provided in a conduit connecting an oil chamber formed before and after another piston of the control cylinder and a second hydraulic pressure source, and a second accumulator is connected between the second hydraulic pressure source and the control valve, A counterbalance device for a mechanical press, comprising: an arithmetic and control device that receives a signal from a detector that detects the inclination of the slide and outputs a command signal to the switching valve and the control valve.