JPS62144900A - Starting method for press machine - Google Patents

Abstract

PURPOSE:To obviate defective mechanical operation at the startup of a press machine by branching and connecting a feedback circuit to a tank to a fluid pressure circuit of a clutch brake and heating the working fluid in the tank to an adequate temp. by circulating said fluid while a safety valve is held communicated. CONSTITUTION:The revolution of a flywheel 17 of the press machine is transmitted to an eccentric shaft 11 via the clutch brake device 15 by which a ram 9 is vertically moved. A fluid pressure cylinder 23 for controlling the connection and disconnection of the device 15 is connected via the fluid pressure circuit 27A to a hydraulic pump 25. A selector valve 31 is provided to the circuit 27A and a safety valve 35 is provided to the feedback circuit 33 branched to a drain circuit 27C. The safety valve 35 is held communicated to circulate the working fluid and the working fluid in the tank T is heated to an adequate temp. by a heater H before the startup. The press machine is then started. The defective mechanical operation prior to the startup of the press machine is thus obviated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention 1] The present invention relates to, for example, a press machine equipped with a flywheel, and more particularly to a method for starting a press machine.

[Technical background of the invention and its problems] For example, a press machine such as a crank press or a punch press is equipped with a rotatable flywheel and a crankshaft (eccentric A clutch/brake device is interposed between the flywheel and the eccentric shaft.

The clutch/brake device has a structure that integrally includes a clutch device and a brake device.

This type of clutch/brake device is composed of a clutch device and a brake device that work together, and when the clutch device is connected (largely activated) to transmit the rotation of the flywheel to the eccentric shaft, the brake device is interlocked. On the other hand, when the clutch device is cut off (disengaged) to cut off the transmission of rotation from the flywheel to the eccentric shaft, the brake device is interlocked and automatically enters the braking state.
(Brakes the rotation of the eccentric shaft and holds it in a stopped state. In other words, the clutch/brake device operates the clutch device at full speed, and at the same time, the brake device puts the eccentric shaft in a rotatable non-braking state, and disengages the clutch device. Upon activation, the brake device is configured to brake and stop the eccentric shaft.

The large operation of the clutch device in the above-mentioned clutch/brake device is performed by supplying working fluid to a fluid pressure cylinder such as a hydraulic cylinder, and the disengaging action is performed by draining the working fluid from the fluid pressure cylinder. This is done by the action of a return spring. That is, the on/off control of the clutch/brake device is performed by the switching operation of a switching valve such as a solenoid valve connected to the fluid pressure cylinder provided in the clutch/brake device.

In the press machine as described above, the operation of the clutch/brake device is controlled by controlling ON/OFF of the solenoid valve, and the rotation and stopping of the eccentric shaft is controlled. When trying to control the rotation and stopping of an eccentric shaft by controlling ON and OFF of a solenoid valve, for example, at the beginning of startup in winter, the working fluid is low temperature and has a high viscosity, so it is difficult to switch the solenoid valve. There is a problem that there is a slight delay in operation and the eccentric shaft cannot be stopped at top dead center.

In order to solve the above problems, conventionally,
A configuration in which the working fluid in the tank is heated using a human-powered heater or the like, or a configuration in which the solenoid valve itself is directly heated are adopted. In a configuration in which the working fluid in the tank is heated by a large heater with a high output, there is a problem that a large amount of energy is required and that the working fluid is likely to deteriorate if heated rapidly. In addition, in a configuration in which the solenoid valve itself is heated, the working fluid is heated locally, and although it has the advantage of requiring less energy for heating, if the working fluid is extremely low temperature, However, there are problems such as the fact that it takes time for the working fluid to reach an appropriate temperature.

[Purpose of the Invention] The present invention was created in view of the above-mentioned conventional problems.The purpose of the present invention is to solve the problem of mechanical operation caused by low temperature and high viscosity of the working fluid before starting the operation of the press machine. An object of the present invention is to provide a starting method that can accomplish the following with an extremely simple configuration.

[Summary of the Invention 1 In order to achieve the above objects, the present invention provides a method for connecting a clutch/brake device in a press machine,
A feedback circuit to the tank is branch-connected to a fluid pressure circuit equipped with a switching valve that controls shutoff, and the safety valve installed in this feedback circuit is maintained in a communicating state to circulate the working fluid and reduce the amount of working fluid in the tank. The press machine starts operating after the working fluid reaches an appropriate temperature.

[Embodiments of the invention] Generally, a press machine 1 equipped with a flywheel is
For example, as shown in FIG.
A ram (slide) 9 is provided above the bolster 5 and is vertically movable and guided vertically by a ram guide 7 provided in the frame 3. The above ram 9 is
It is interlocked and connected via a connecting rod 13 to an eccentric portion (not shown) of a spacing center @ 11 rotatably supported by the frame 3 . The eccentric shaft 11 is connected to and disconnected from a flywheel 17 rotatably supported by the frame 3 via a clutch/brake device 15 (see FIG. 1).

Since the clutch/brake device 15 has a general configuration, detailed explanation thereof will be omitted.

A lower mold 19 is mounted on the bolster 5, and an upper mold 21 is mounted on the ram 9.

In the press machine 1 having the above configuration, the clutch
By connecting the flywheel 17 and the eccentric shaft 11 via the brake device @15, the rotation of the flywheel 17 is transmitted to the eccentric IN111, and the rotation of the eccentric shaft 11 causes the ram 9 to move up and down. be. and,
The workpiece W is pressed between the lower mold 19 and the upper mold 21.

The clutch/brake device 15 is provided with a fluid pressure cylinder 23 such as a hydraulic cylinder for controlling the connection/disconnection of the clutch/brake device 15 . This fluid pressure cylinder 23 and a pressure source 25 such as a hydraulic pump are connected via a fluid pressure circuit 27Δ. In addition, the fluid pressure circuit 27A and the clutch/brake device 15 are
It is connected via the lubricating oil path 27B, and the lubricating oil path 27B
The working fluid from the tank T is passed through the drain circuit 27C.
It is being refluxed to. An accumulator 29 is connected to the fluid pressure circuit 27A, and an accumulator 29 is connected to the fluid pressure circuit 27A.
A solenoid valve 31 is provided which can freely connect and cut off the communication. Furthermore, a drain circuit 27 is branched from the fluid pressure circuit 27A.
The branch circuit (feedback circuit) 33 connected to C is provided with a safety valve 35 made of a solenoid valve that can freely disconnect or disconnect the branch circuit 33.

As can be understood from the above configuration, the solenoid 5QL2 of the safety valve 35 is demagnetized and the safety valve 35 is used to control the branch circuit 3.
3 is kept connected, the working fluid from pressure source 25 is released to atmospheric pressure. Therefore, even if the solenoid 5OL1 of the solenoid valve 31 is excited and the solenoid valve 31 is switched, the working fluid is not supplied into the fluid pressure cylinder 23 of the clutch/brake device 15, and the clutch/brake device 15 is not supplied with working fluid. The device 15 is in a disconnected state and the eccentric shaft 11 is stopped.

In other words, by demagnetizing the solenoid 5QL2 of the safety valve 35, the rotation of the eccentric shaft 11 is stopped, and the working fluid is circulated from the fluid pressure circuit 27△ to the drain circuit 27C and from the lubricating oil path 27B to the drain circuit 27C. It will be understood that the condition

As a result of the above, before starting operation of the press machine 1, the safety valve 3
By demagnetizing the solenoid 5OL2 of No. 5, circulating the working fluid in advance, and heating the working fluid with the heater H provided in the tank T, the temperature of the working fluid and the fluid pressure circuit system can be raised. In this case, even if the heater H has a relatively small capacity, it is possible to easily raise the temperature of the working fluid depending on the circulation flow of the working fluid. Therefore, it is possible to eliminate defects in mechanical operation at the time of starting the press machine 1. Note that the temperature of the working fluid can be detected by a sensor (not shown) provided at an appropriate location, and by appropriately controlling the heater H based on the detected value of the sensor, the working fluid can be maintained at an appropriate temperature.

When the solenoid 5QL2 of the safety valve 35 is excited, the branch circuit 33 is cut off. Therefore, by appropriately energizing the solenoid 5OL1 of the solenoid valve 31 and switching the circuit, the supply and drain of the working fluid to the hydraulic cylinder 23 of the clutch/brake device 15 are controlled, and the rotation and stop of the eccentric shaft 11 are controlled. It is something that is controlled.

A control circuit 37 is provided to control excitation and demagnetization of the solenoid 5QL1 of the solenoid valve 31 and the solenoid 5QL2 of the safety valve 35. More specifically, as shown in FIG. 2, the control circuit 37 includes a clutch drive circuit 39 that controls the solenoid 5OL1 of the solenoid valve 31, a safety valve drive circuit 41 that controls the solenoid 5QL2 of the safety valve 35, and a safety valve drive circuit 41 that controls the solenoid 5QL2 of the safety valve 35. It is composed of a safety detection circuit 43 that controls ON and OFF of the

When the clutch drive circuit 39 receives a press operation signal P from an appropriate control device (not shown) such as a numerical control device, it energizes the solenoid 5OL1 of the solenoid valve ♂1, and switches the clutch disconnection switch LS1. When this signal is input, the solenoid 5OLI is demagnetized.

The clutch disconnection switch SL1 is activated by a dog or the like provided on the eccentric shaft 11 immediately before the eccentric shaft 11 reaches the top dead center, and is, for example, a limit switch, a proximity switch, or the like.

When the clutch disconnection switch SL1 is operated, the clutch of the clutch/brake device 15 is disconnected, the brake is applied, and the eccentric shaft is stopped at the top dead center.

The safety valve drive circuit 41 operates the solenoid 5 of the safety valve 35 in response to an ON signal input from the safety detection circuit 43.
QL2 is excited and demagnetized by the OFF signal.

The safety detection circuit 43 detects whether there is any abnormality in the press machine 1, and is configured to immediately output an OFF signal to the safety valve drive circuit 41 when an abnormality is detected. This safety detection circuit 43 is connected to, for example, an emergency stop button or an emergency stop input section 45 of an abnormality detection device that detects various abnormalities. As will be described later, the above abnormality detection device detects abnormalities such as overrun of the eccentric shaft 11, inoperation due to poor electrical connection, etc., and failure of the eccentric shaft 11 to return from bottom dead center to top dead center. be. j5, the safety detection circuit 43 is reset by a reset signal R from the control device.

Referring to FIG. 3, when the eccentric shaft 11 is stopped at the top dead center and the top dead center detection device consisting of, for example, a cam and a limit switch is in the ON state, a press operation signal is sent to the clutch drive circuit 39. When P is input, the rise of the press operation signal P excites the solenoid 5QL1 of the solenoid valve 31, and turns on the timer T1 in the abnormality detection device. This timer T1
is in an ON state for a slightly longer time than the time when the top dead center detection device is turned OFF, and then turned OFF.

By energizing the solenoid 5OLI of the solenoid valve 31, the clutch/brake device 15 is connected, and the eccentric shaft 11 starts rotating from the top dead center. Eccentric shaft 11
When the top dead center detection device turns OFF due to the rotation of , timer T2 in the abnormality detection device turns ON due to the fall of
activated.

This timer T2 remains ON for a slightly longer time than the time sufficient for the eccentric shaft 11 to rotate once, and then turns ON.
This is the FF state.

As mentioned above, just before the eccentric shaft 11 rotates and passes through the bottom dead center and reaches the top dead center, the clutch disconnect switch LS is activated.
1 is turned on. This clutch disconnect switch LSI
The rise of the ON operation causes the press operation signal P to fall, and the fall of this press operation signal P demagnetizes the solenoid 5OL1 of the solenoid valve 31. Therefore, the clutch/brake device 15 is disconnected and the eccentric shaft 11
reaches top dead center and stops due to inertia. When the eccentric shaft 11 reaches the top dead center, the top dead center detection device starts up.

It becomes ON state. As the top dead center detection device rises, the timer T2 is lowered and becomes OFF.

11η, where the eccentric shaft 11 should stop at the top dead center, for example, the solenoid SQL of the solenoid valve 31
“If I is not demagnetized, or solenoid 5OL1
has been demagnetized, but if switching is not performed due to mechanical failure or the like, the eccentric shaft 11 continues to rotate. In this case, both the top dead center detection device J3 and the press operation signal P are 1.
．． : An abnormality in the press machine 1 is detected on the condition that it is turned OFF and the rotation state of the solenoid 5OLI or the eccentric shaft 11 is turned ON.

Upon detection of the above abnormality, the solenoid 5 of the safety valve 35 is immediately activated.
When QL2 is demagnetized and the working fluid in the fluid pressure circuit 27 is released to atmospheric pressure, the clutch/brake system @15 is disengaged.
The eccentric @l111 stops rotating. In other words, the rotation of the eccentric shaft 11 in the event of an abnormality is stopped, thereby ensuring safety.

Note that the rotation state of the eccentric shaft 11 is detected as ON or OFF by using a rotation detector such as a generator or a pulse encoder to detect whether the eccentric shaft 11 is rotating to 0 or stopped. The time is set to the ON state.

Referring to FIG. 4, as described above, when the eccentric @11 is stopped at the top dead center, the press operation signal P is input to the clutch drive circuit 39 to start the rotation of the eccentric shaft 11. At this time, when the eccentric N11 is not rotated and stopped at the top dead center, and the timer T1, which was in the ON state, falls after the set time has elapsed, the top dead center detection device is in the ON state. In this case, an abnormality in which the rotation of the eccentric 'N111 does not start is detected, and the solenoid 5QL2 of the safety valve 35 is demagnetized to ensure safety so that the eccentric shaft 11 does not suddenly start rotating.

In addition, as mentioned above, timer T2 is in the ON state,
When the timer T2 falls down after the set time has elapsed, and the top dead center detection device is in the OFF state, an abnormality in which the eccentric shaft 11 is not returned from the bottom dead center to the top dead center is detected, and the safety valve 3 is activated.
This is to ensure safety by demagnetizing solenoid S○L2 of No.5.

[Effects of the Invention] As can be understood from the above description of the target embodiment, the gist of the present invention is as stated in the claims. The temperature of the working fluid can be raised to an appropriate temperature in advance, and the temperature of the working fluid circuit system can also be raised, which easily solves the conventional problem of the solenoid valve switching operation tending to be delayed at the beginning of the press machine startup. It is something that can be resolved.

Note that the present invention is not limited to the above-described embodiments, but can be implemented in other embodiments by making appropriate changes. For example, a detector such as a pulse encoder is connected to the central shaft, the rotation angle of the eccentric shaft is detected by the output signal from this detector, and the necessary control signal is generated according to the rotation angle. The control device can be modified in any appropriate manner, such as by configuring the control device so that the output is low and omitting a clutch disengagement switch or the like.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the fluid pressure circuit showing the main parts, Figure 2 is a block diagram of the control circuit, Figures 3 and 4 are timers 1 to 4, and Figure 5 is an explanatory diagram of a general press machine. It is. 1...Press machine 15...Clutch/brake device 27A...Fluid pressure circuit 27C...Drain circuit 3
1...Solenoid valve (switching valve) 35...Safety valve T...Tank H...Heater (warming device) Agent Patent attorney Yasu Miyoshi;, - knee: σ" LM Figure 1 1c:I Fig. 2 Control circuit Fig. 3 Fig. 4tXl

Claims (1)

[Claims] A feedback circuit to the tank is branch-connected to a fluid pressure circuit equipped with a switching valve that controls the connection and disconnection of clutch and brake devices in press machines, and the safety valve installed in this feedback circuit is maintained in a communicating state to operate. A method for starting a press machine, which comprises circulating fluid and warming the working fluid in a tank with a heating device, and starting operation of the press machine after the working fluid has risen to an appropriate temperature.