JPS59150700A - Device for correcting bottom dead point position of slide of press machine - Google Patents

Abstract

PURPOSE:To correct automatically the bottom dead point position of a slide without decreasing production efficiency by controlling the air pressure to be supplied to counter balancers in accordance with the signals relating to the bottom dead point of sensors which detect the bottom dead point position of the slide. CONSTITUTION:A flywheel 10 is rotated by a motor 11 to revolve a crank shaft 7 which moves vertically a slide 5 by means of connection screws 6. Pressing is accomplished by a punch 16 and a die 15. On the other hand, the bottom dead point of the slide 5 is detected by sensors 14. The outputs from the sensors are fed to a control circuit by which the difference from a standard value is decided at all times. If the difference between the reference position and the bottom dead point position exceeds continuously a prescribed value by N-times (preset adequately), the air pressure optimum for correcting the difference is selected and is supplied to counter balancers 9. The bottom dead point position of the slide is thus automatically corrected during the operation of a press machine 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bottom dead center position correcting device for a slide of a press machine.

Press machines generally have a problem in that the bottom dead center position of the slide changes when operating at high speeds or for long periods of time.

The reason for this is that the higher the press speed, the greater the inertia applied to the slide, which causes the bottom dead center of the slide to drop due to gaps around the crank, and the fact that the press machine is not operated for long periods of time. When the press is operated, the heat generated by the press causes the connecting parts such as the connecsine to thermally expand, causing the bottom dead center of the slide to drop, and if the operation continues, the frame (especially the column and tie rods) may become damaged. There were cases where the bottom dead center of the slide lowered due to thermal expansion.

Therefore, in order to compensate for such changes in the bottom dead center position, conventional measures have been taken such as installing a stopper to limit the bottom dead center position or making fine adjustments to the press machine one by one. was.

However, in the former case, there are problems such as loss of press machine capacity and difficulty in adjusting the stopper in precision machining, and in the latter case, it is extremely time-consuming and requires a lot of effort to operate the press machine. There was a problem in that the rate actually decreased.

Therefore, in view of the above, the present invention aims to provide a bottom dead center position correction device for a press machine that can automatically correct the bottom dead center position without causing any loss in press machine capacity. It is something to do.

In order to achieve the above object, the present invention provides a press machine of a type having a counter balancer for offsetting the weight of the slide by air pressure, and a sensor for detecting the bottom dead center position of the slide, and a sensor for detecting the bottom dead center position of the slide. The present invention is characterized by further comprising a control circuit that controls the air pressure of air supplied to the counter balancer based on a signal related to the position.

Hereinafter, before a detailed explanation of the present invention, a counter balancer will first be explained. In the press machine 1, the slide 5 and the crankshaft 7 are connected by a connection screw 6 and a connection 8, and there are several connecting parts (not shown) between them. Naturally, there is a slight gap in this connection part during assembly, but this gap is filled with the slide 50.
Everything is pushed to the bottom by weight.

By the way, when the press 1 is operated in this state, a force is applied to pull up the slide 5, but as mentioned above, the gap is biased towards the bottom, so even if you try to pull up the slide 5, the slide 5 will not move by this gap. response is delayed. This is usually called the breathing phenomenon.

Therefore, in order to eliminate this breathing phenomenon and realize smooth movement of the slide 5, the counter balancer 9 is designed to lift the weight of the slide 5 and the upper die 16 using air pressure and maintain balance. The present invention attempts to use this counter balancer 9 to adjust variations in the bottom dead center position of the slide 5.

Next, one embodiment of the present invention will be described in detail with reference to the drawings.

First, to briefly explain the press machine 1, the bed 2
A bolster 6 is provided on the upper part of the holder. Four tie rods 4 are erected on the bed 2. A connection screw 6 is swingably provided at the upper part of the slide 5, and this connection screw 6 is screwed onto a connection shaft 8. Furthermore, the connection shaft 8 is provided so as to be swingable relative to the crank pin 8a. On the other hand, a flywheel 10 is provided on the crankshaft 7 which is rotatably supported by bearings 7a, 7a, and this flywheel 10 is connected via a belt 16 to a pulley 12 provided on the rotating shaft of the motor 110. ing. In addition, the motor 11 includes a motor body, a coupling,
A variable speed motor consisting of a tacho generator is used. A counter balancer 9 is provided above the slide 5, and a rod 9a of the counter balancer 9 is connected to the slide 5. The counter balancer 9 has a cylinder chamber 9C and a piston 9 as shown in FIG.
Air pressure setting circuit 2 is installed in the same cylinder chamber 9C.
Air is supplied from 6. In this example, the air pressure setting circuit 26 is a solenoid pulp E+1. A first pneumatic circuit 232L consisting of a relief valve R1 and a pressure reducing valve f1, a second pneumatic circuit 23b consisting of a solenoid pulp 13211J'J-Fvalp R2 and a pressure reducing valve, a solenoid pulp s3, a relief pulp R6 and a pressure reducing valve f6. In this example, the pressure reducing valve f1 of the first pneumatic pressure circuit 23a is set to 5 kg/cot, and the pressure reducing valve f2 of the second pneumatic pressure circuit 26''o is set to 4 kg/C[
++, and the pressure reducing valve f6 of the sixth pneumatic circuit 230 is set to 5 kg/cnl. For this reason, solenoid pulp s1. s2. By opening and closing s3 individually, 3 kg/d, 4 kg is applied to the cylinder chamber 9c.
It is possible to supply different air pressures of /ad and 5kg/ad. Note that 7 kg/cut of air is supplied to the air supply hole AI from a compressor or the like (not shown).

On the other hand, two sensors 14 and 14 for detecting the bottom dead center position of the slide 5 are mounted on the bolster 3.
A and 14a are provided at both ends of the bolster 6, respectively. In this example, a magnetic sensor having a coil (not shown) inside is used as the sensor 14.14. However, other methods such as capacitive sensors and ultrasonic sensors may also be used.

15 is a lower die attached to the bolster 5, and 16 is an upper die attached to the slide 5.

Next, the control circuit 17 will be explained. The control circuit 17 is connected to the detection circuit 18 as shown in FIG.

The detection circuit 18 includes an oscillation circuit, a voltage detection circuit, and an average value circuit (not shown). The high frequency output from the oscillation circuit is applied to a coil (not shown) of the sensor 1414, and the voltage values generated between both terminals of this coil are detected by a voltage detection circuit. When the pick and slide 5 come close to the sensor 14.14, the magnetic permeability of the coil of the sensor 14.14 changes depending on the close distance. Then, the voltage value generated between both terminals of the coil to which the high frequency voltage is applied changes, and this is detected by the voltage detection circuit. However, the value detected by this voltage detection circuit is a value related to the distance between the slide 5 at the bottom dead center position and the sensor 14. Each voltage value detected by this voltage detection circuit is input to an average value circuit, the average value of which is taken, and then input to the AD converter 19.

The A-D converter 19 is for converting the signal from the detection circuit 18 regarding the distance between the sensor 14 and the slide 5 at the bottom dead center position from analog to digital. The generated signal is input to the CPU 20.

The 0PU 20 inputs a signal related to the distance from the A-D converter 19, and calculates the difference from a reference value (reference distance h) set in advance in the CPU 20. When the limit value is exceeded N times (the value of N is appropriately set in advance) in succession, a predetermined control signal (this exceeded amount and the control signal) is generated depending on the degree of the exceeded amount. The correspondence relationship is set in advance in the CPU) and is configured to be output to the selection circuit 21.

The selection circuit 21 inputs the control signal from the 0PU 20 and selects the solenoid valve s L s 2t s 3 in the electromagnetic valve selection circuit 22 corresponding to this signal, and is configured as a kind of decoder. There is.

The solenoid valve selection circuit 22 includes a relay (not shown), its relay contacts RL1a, RL2a, and RL3a, and the solenoid valve s1. s2. It is mainly composed of s3.

These relay contacts RL1a-RL3a are connected to the selection circuit 21.
A relay RL (not shown) activated by a control signal from
When the normally open contacts of i to RL3 turn on, the solenoid valve connected in series to this contacts operates, and the air pressure setting circuit 26 sets a predetermined air pressure to the counter balancer. 9.

In addition, 24 is an electromagnetic switch.

In the above configuration, when the motor 11 is rotated, the pulley 12. Belt 16. The crankshaft 7 rotates via the flywheel 10. Then, the slide 5 is moved up and down in the drawing by the screw 6 connected to the crank pin 8a. That is, the press is performed by the vertical movement of the slide 5.

On the other hand, the bottom dead center of the slide 5 is detected by the sensors 14, 14, and the resulting signal regarding the distance between the sensor 14 and the slide 5 is sent to the detection circuit 18. The signal is input to the OPU 3O via the A-D converter 19. and,
The CPU 20 calculates the difference between the signal input thereto and a reference value (reference distance h) preset in the CPU 20, and determines whether this difference exceeds a limit value preset in the 0PU20. I am always deciding whether or not to do so.

Now, for example, pressure 3 is applied to the counter balancer 9 of press machine 1.
kg/- of air is being supplied (therefore, the solenoid valve S1 is operating), and if continuous operation is performed and the bottom dead center of the system slide 5 is lowered due to thermal expansion, etc., 0PU20 is as described above. This is detected when the difference from the reference value exceeds a preset limit value, and if this difference exceeds the limit value N times in a row (the value of N is set appropriately in advance). Then, a predetermined control signal is output to the selection circuit 21 in accordance with the degree of the amount exceeded. Then, the selection circuit 21 operates a predetermined onlay (not shown) corresponding to the control signal (this correspondence is set in advance). For example, if this is a relay R1, 2 (not shown), its normally open contact RL2a is turned on, and the solenoid pulp S2 is activated. (At this time, the operation of the solenoid valve S1 is released.) Therefore, the counter balancer 9 is supplied with 4k from the second pneumatic circuit 23b.
Since air with a pressure of g/cnl is supplied, the slide 5 is pulled upward by the counter balancer 9, but the force increases. Therefore, the bottom dead center position of the slide 5 is raised by a predetermined amount by this air pressure, so that the lowered bottom dead center position is returned to the proper position again, and the press is executed in the optimum condition.

In this embodiment, the slide 5 is controlled by the sensor 4.
When the change in the bottom dead center position of the engine is detected, and if this change, that is, the difference between the reference value and the bottom dead center position exceeds a predetermined value N times in a row, the optimum air pressure is set to correct this change. It is selected and supplied to the counter balancer 9. (The relationship between the amount of change in the bottom dead center position and the supplied air pressure is set in advance.) By doing this, it is possible to automatically correct the bottom dead center position of the slide while the press machine 1 is operating. Therefore,

In addition, in this example, there are six pneumatic circuits 23a and 23b.

Although the case has been described in which there are 230, it goes without saying that this number may be increased or decreased as appropriate. Further, in this example, the case where the bottom dead center position has lowered has been explained, but it goes without saying that correction can be performed by similar control even when the bottom dead center position has risen.

That is, the present invention provides a press machine having a counter balancer for offsetting the weight of the slide by air pressure, and a sensor for detecting the bottom dead center position of the slide, and a signal from this sensor regarding the bottom dead center position to control the counter balancer. By providing a control circuit for controlling the air pressure of the air supplied to the press, it has an excellent feature that the bottom dead center position can be automatically corrected without any loss in press capacity.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is an explanatory diagram showing the overall configuration of a press machine, and FIG. 2 is a block diagram of a control circuit. 1...Press machine 5...Slide 9...
Counter balancer 14...Sensor 17...For control circuit Applicant Yamada Dobby Kaisha, Ltd. Attorney Patent attorney Oka 1) Hidehiko Figure 1

Claims (1)

[Claims] In a type of press machine that has a counter balancer for offsetting the weight of the slide by air pressure, air is supplied to the counter balancer based on a sensor that detects the bottom dead center position of the slide and a signal from this sensor regarding the bottom dead center position. A bottom dead center position correction device for a slide, comprising a control circuit for controlling the air thickness of the slide.