JPH0726080Y2 - Slide top dead center position adjustment device for hydraulic drive press - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention automatically adjusts the top dead center position of a press slide in a slide position adjusting device of a hydraulic press, particularly in a hydraulic press driven by a constant discharge type hydraulic pressure generating device. The present invention relates to a press slide top dead center position adjusting device for adjustment.

[Prior Art] There is a hydraulic press that uses a crank type constant discharge type hydraulic pressure generator as a drive source. This hydraulic pressure generating device is already known, for example, from Japanese Patent Laid-Open No. 61-255281 or Japanese Patent Laid-Open No. 61-255283, both of which support a cylinder swingably by a swing shaft and move in and out of the cylinder. It has a structure that allows the slide to be actuated by a crankshaft or an eccentric shaft driven by an electric motor, to enable instantaneous start and stop, discharge of a fixed amount of hydraulic oil, and suction. The slide pressurizing chamber of the cylinder of the hydraulic press and the pressure oil discharge port of the hydraulic pressure generator are connected by a pressurizing circuit, and the slide pullback chamber of the press cylinder and the pressure oil suction port of the hydraulic pressure generator are pullback circuit. The pressure oil is reciprocated in the pressurizing circuit and in the pulling circuit by driving the hydraulic pressure generator. Therefore, although the vertical movement of the press slide and the vertical movement of the slide of the hydraulic pressure generator are synchronized, oil leakage from the seal material on the press side and the pipe line at the time of valve switching when operating a plurality of presses by pulse switching Since the stroke of the press slide may vary due to the fluctuation of the amount of internal oil, conventionally, the position of the slide is detected by a plurality of limit switches, and the slide position is adjusted by the control valve of the pressurizing circuit.

[Problems to be Solved by the Invention] In the above-mentioned conventional adjustment of the press slide stroke by the limit switch and the control valve, the automatic stepless setting of the upper and lower limit positions of the slide stroke, especially the upper limit (top dead center) position thereof cannot be performed. However, the accuracy is poor, and it is difficult to arbitrarily change the stop position of the press slide top dead center according to the thickness of the material to be processed. The structure is also complicated, which causes a high cost.

The present invention is a slide of a hydraulically driven press that can automatically correct the variation of the stop position of the top dead center of the press slide and can change the position of the top dead center of the press slide arbitrarily and accurately according to the thickness of the work material. It is to provide a top dead center position adjusting device.

[Means for Solving the Problems] A slide top dead center position adjusting device in a hydraulic drive press according to the present invention is a position for detecting a current position of a slide which is constantly operating in each of a constant discharge type hydraulic pressure generating device and a hydraulic press. A detector is provided, and a press slide position adjusting hydraulic pump is connected to a pressurizing circuit from the hydraulic pressure generator to the hydraulic press via a supply / discharge switching solenoid valve to determine the amount of pressure oil in the pressurizing circuit. The control signals are obtained by subtracting the signals from both the position detectors, and the supply / discharge switching solenoid valve operated by the control signals controls the amount.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an overall system diagram of a slide top dead center position adjusting device according to an embodiment of the present invention. In this embodiment, a plurality of hydraulic presses 2a and 2b are connected to one constant discharge type hydraulic pressure generator, and the plurality of presses are sequentially operated by switching valves. The hydraulic pressure generating device 1 has a crank type constant discharge type structure as described in the above-mentioned Japanese Patent Laid-Open No. 61-255281, and the cylinder 14 has a swing shaft 15 according to the movement of the slide 16. One end of the slide 16 is connected to a crankshaft 17, and the slide 16 reciprocates in the cylinder 14 driven by an electric motor. The hydraulic oil discharge port 14a of the hydraulic pressure generator 1 is connected to the slide pressurizing chamber of the press cylinder 18 of each hydraulic press 2a, 2b through the pressurizing circuit 8, and the hydraulic pressure is generated between the slide pulling chamber of the press cylinder 18 of each press. The hydraulic fluid withdrawal chamber of the device 1 is connected by the withdrawal circuit 11, whereby the slide 3 of each hydraulic press 2a, 2b performs the same crank motion as the slide 16 of the hydraulic pressure generator 1. Each hydraulic press 2a, 2
Switching valves 6a, 7a and 6b, 7b are provided in the pressurizing circuit 8 and the pulling circuit 11 for each b, and the switching valve is excited only for the press to be used.

In the following description, the first hydraulic press 2a will be described.
The description of the operation of the other hydraulic press 2b is omitted. The slide 3 of the hydraulic press 2a and the slide 16 of the hydraulic pressure generating device 1 are respectively provided with ably coater type position detectors 4 and 5, whereby the current positions of the slides 3 and 16 which are always operating are detected.

A shutoff valve 9 and a proportional solenoid valve are provided in the middle of the pressurizing circuit 8.
A press slide position adjusting hydraulic pump 13 is connected via 10. The proportional solenoid valve 10 is operated by the signals from the position detectors 4 and 5, and controls the amount of pressure oil that enters into the pressurizing circuit 8 from the hydraulic pump 13, thereby generating the hydraulic pressure at the top dead center position of the press slide 3. Adjust so as to match the top dead center position of the slide 16 of the device 1. On the other hand, the pullback circuit 11 is constantly applied with the preload pressure by the accumulator 12 and always presses the press slide 3 to the upward side during operation. The withdrawal circuit 11 is also connected to the hydraulic pump 13 so that an withdrawal preload is applied, and the adjusting hydraulic oil of the withdrawal circuit 11 at the time of adjusting the slide stroke position is taken in.

When using the hydraulic press 2a with the above configuration, first the switching valves 6a and 7a are excited to excite the cylinder 1 of the constant discharge type hydraulic pressure generating device 1.
4 and the press cylinder 18 of the hydraulic press 2a are connected. Now, it is assumed that the slide 16 of the hydraulic pressure generating device 1 has just stopped at the top dead center, and the press slide 3 is displaced up and down from the desired top dead center position (point 0 in the figure). When the stop position of the press slide 3 is Y ₁ above this 0 point (detected by the position detector 4), the shut-off valve 9 is turned on and the SOL _a of the proportional solenoid valve 10 is turned on to pressurize the circuit. Pressure oil is introduced from the hydraulic pump 13 to 8, and the press slide 3 is lowered by Y ₁ minutes. This is because the signals of both position detectors 4 and 5 are subtracted to obtain a control signal, and the proportional solenoid valve is operated by this control signal.
It is realized by operating 10. The control signal is subtracted, and when it becomes zero, the proportional solenoid valve 10 is turned off. On the contrary, when the stop position of the press slide 3 is Y ₂ downward from the 0 point, the SOL _b side of the proportional solenoid valve 10 is turned on, the pressure oil in the pressurization circuit 8 is released to the tank port, and the pullback circuit is released. Pressure oil is introduced from the hydraulic pump 13 of 11 or the accumulator 12 to raise the press slide 3.

As described above, the top dead center position of the press slide 3 is always matched with the top dead center position of the slide 16 of the hydraulic pressure generator 1. When the amount of displacement of the press slide from the 0 point is large, the proportional solenoid valve 10 is fully opened, the press slide is moved at high speed, and when it is near the 0 point, the speed is lowered to perform fine adjustment. Also, the same operation as described above is performed when it is desired to lower the top dead center of the press slide 3 by Y ₂ depending on the thickness of the work material. If the top dead center of the hydraulic pressure generating device 1 is deviated by x amount and stopped, the press slide 3 is further lowered by that amount so that the press slide 3 always performs a correct motion.

Since the press slide 3 can be moved up and down at a very low speed by switching the proportional solenoid valve 10 without driving the hydraulic pressure generating device 1, this method is used for the press vertical mold matching. When multiple hydraulic presses 2a and 2b are driven sequentially by switching valves, oil leakage etc. occurred in the switching valve or seal material of one of the hydraulic presses, causing the press slide to be displaced relative to the slide of the hydraulic pressure generator. Even at this time, the top dead center position of each press slide can be maintained at a desired position by the control of the proportional solenoid valve 10 by the operation comparison based on the signal of each position detector. Although the pressurizing circuit 8 and the hydraulic pump 13 are connected via the proportional solenoid valve 10 in the above embodiment, a supply / discharge switching solenoid valve may be used instead of the proportional solenoid valve.

[Effects of the Invention] As described above, the present invention connects the supply / discharge switching solenoid valve and the hydraulic pump to the pressurization circuit from the constant discharge type hydraulic pressure generator to the hydraulic press to stop the press slide at the top dead center. Since the amount of oil in the pressurizing circuit is controlled by the solenoid valve in accordance with the amount of variation in position, it is possible to always perform a correct motion according to the slide stroke of the hydraulic pressure generator.

When a proportional solenoid valve is used, the press slide stroke variation is promptly corrected, and the stop accuracy is ± 1.0 m.
It can be improved to m or less. There is an effect that it is possible to quickly respond to a change in the thickness of the work material, and even when a plurality of presses are sequentially driven by one hydraulic pressure generating device, the press slide position can always be kept at a desired position.

[Brief description of drawings]

FIG. 1 is an overall system diagram of a press slide top dead center position adjusting device according to an embodiment of the present invention. 1 …… Constant discharge type hydraulic pressure generator 2a, 2b …… Hydraulic press 3 …… Press slide 4,5 …… Position detector 6a, 6b, 7a, 7b …… Switching valve 8 …… Pressure circuit 9 …… Shut Off valve 10 …… Proportional solenoid valve 11 …… Retractor circuit 13 …… Pressure slide position adjusting hydraulic pump 14 …… Hydraulic generator cylinder 16 …… Hydraulic generator slide 17 …… Crankshaft 18 …… Pris cylinder

Claims (1)

[Scope of utility model registration request] 1. A constant discharge type hydraulic pressure generating device and a hydraulic press are each provided with a position detector for detecting the current position of a slide which is always operating, and is supplied to a pressurizing circuit from the hydraulic pressure generating device to the hydraulic press. A press slide position adjusting hydraulic pump is connected via a discharge switching solenoid valve, and the amount of pressure oil in the pressurizing circuit is adjusted so as to synchronize the press slide with the slide of the hydraulic pressure generator. A slide position adjusting device for a hydraulically driven press, wherein a control signal obtained by subtracting a signal from the control unit is used to adjust the supply / discharge switching solenoid valve.