JPS6363317B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a clutch/brake control valve used in a press machine.

For press machines equipped with air-operated clutch brakes, it is necessary to accurately control the air supplied to the clutch brake, and it is also necessary to provide ON/OFF speed and abnormal stop functions for the clutch brake. There is.

For this reason, clutches and brakes are conventionally controlled using double-valve parallel flow, but such double-valve parallel flow is expensive and requires air flow during ON/OFF and when a solenoid valve malfunctions. There was a drawback that the outflow rate could not be sufficiently increased.

In order to eliminate such drawbacks, air is supplied to the tank through a throttle as shown in Utility Model Publication No. 54-44500. This system is designed to detect a valve abnormality by detecting a drop in tank pressure.

However, in press machines, in order to alleviate the shock to various parts of the mechanism due to sudden engagement of the clutch, a throttle is usually inserted between the tank and the valve to alleviate the shock. The pressure of the tank does not drop suddenly, and the detection accuracy decreases because the valve malfunction is detected by using changes in the internal pressure of a large-capacity tank, or if the valve is unable to pump air. If a failure occurs in this condition, the pressure will not be lowered, so there is a problem that such an abnormality in which evacuation is not possible cannot be detected.

The present invention was made to solve these conventional problems, and although it has a simple and inexpensive configuration, it minimizes the decrease in the air inflow and outflow speed even in the event of a valve failure. It is an object of the present invention to provide a control valve for a clutch/brake for a press machine, which can suppress the problem to a certain limit and can accurately detect abnormalities in the valve.

In order to achieve the above object, the present invention provides a third press machine equipped with a clutch/brake that transmits power only when air is supplied.
First and second electromagnetic three-way valves whose ports are open to the atmosphere, and first and second pressure switches that detect the pressure at the second ports of the first and second electromagnetic three-way valves are provided. , a first port of the first electromagnetic three-way valve is connected to an air supply source, and is also connected to an air chamber of a clutch/brake connected to a second port of the second electromagnetic three-way valve. Then, by connecting the second port of the first electromagnetic three-way valve to the first port of the second electromagnetic three-way valve, the pressure in the second port of the first electromagnetic three-way valve is changed to the first electromagnetic three-way valve. The present invention is characterized in that the pressure is detected by a pressure switch, and the pressure at the second port of the second electromagnetic three-way valve is also detected by the second pressure switch.

Therefore, under normal conditions, the outputs of both pressure switches change almost simultaneously without any substantial time delay, but if at least one solenoid 3-way valve fails while in the OFF state, the clutch/brake Safety is guaranteed because no air is supplied to the Additionally, if the first solenoid 3-way valve fails while it is in the ON state, the output of the first pressure switch will not change at all, so the abnormality can be detected, and the failure will occur if the second solenoid 3-way valve is in the ON state. When this happens, the outputs of both pressure switches will be exactly the same, making it possible to detect an abnormality.

Embodiments of the present invention will be described in detail below based on the drawings.

In FIG. 1, an air line 2 connects an air supply source (not shown) and an air chamber of the clutch/brake 1.
Inside, first and second electromagnetic three-way valves 3 and 4 are provided. In both of these electromagnetic three-way valves 3 and 4, the first port on the air supply source side is normally closed and the second port on the clutch/brake 1 side is the third port open to the atmosphere. However, when the solenoids SOL1 and SOL2 of the three-way electromagnetic valves 3 and 4 are energized, the third port is closed and the first and second ports are brought into communication.

Further, by installing pressure switches 5 and 6 on the downstream side of each of the electromagnetic three-way valves 3 and 4, that is, on the second port of each electromagnetic three-way valve 3 and 4,
The ON/OFF state of the pressure switches 5, 6, in other words, the operating state of the electromagnetic three-way valves 3, 4 is detected through the pressure of the second port of each electromagnetic three-way valve 3, 4. .

In the above configuration, when at least one of the first and second electromagnetic three-way valves 3 and 4 is in the OFF state, the air chamber of the clutch/brake 1 is exposed to the atmosphere via the electromagnetic three-way valve in the OFF state. Since it is released, the clutch/brake remains in the OFF state. or,
When both the electromagnetic three-way valves 3 and 4 are turned on, air is sent from the air supply source to the air chamber of the clutch/brake 1 through the two electromagnetic three-way valves 3, 4, and the clutch/brake 1 is turned on. be done. still,
Even if either one of the solenoid 3-way valves is in the ON state, if the other solenoid 3-way valve is turned OFF, this
The air chamber of the clutch/brake 1 is opened to the atmosphere through the solenoid three-way valve that is turned OFF, so the clutch/brake is turned OFF.

In addition, if at least one of the three-way electromagnetic valves is turned on and malfunctions, the pressure switches 5 and 6 are turned on and off after a predetermined period of time has elapsed since the clutch/brake 1 was turned off, as shown in the flowchart shown in Figure 2. OFF
A condition is detected. If one of the pressure switches 5, 6 is ON, that is, the pressure switches 5, 6 are malfunctioning, or the electromagnetic three-way valves 3, 4 are turned on.
When a malfunction is detected in the ON state, the alarm lamps 7 and 8 light up to notify that the electromagnetic three-way valve or pressure switch 5 and 6 is malfunctioning, and at the same time, a stop signal is sent to the press machine. is output. Therefore, when the three-way electromagnetic valves 3 and 4 are in the ON state and are malfunctioning, the press machine cannot be operated.

Note that at least one of the electromagnetic three-way valves 3 and 4 is
When there is a failure in the OFF state, the clutch/brake 1 remains OFF as described above, and the press machine cannot operate. Therefore, if at least one of the three-way electromagnetic valves is out of order, the press machine will not be operated, so the safety of the operator and the press machine is guaranteed.

FIG. 3 is a flowchart when the press machine is operated. When the operation button is pressed to operate the press machine, the solenoid of the first electromagnetic three-way valve 3 is activated.
SOL1 is turned on, and along with this, the first pressure switch 5 is turned on. Next, the solenoid SOL2 of the second electromagnetic three-way valve 4 is turned on, the second pressure switch 6 is turned on, and when both the electromagnetic three-way valves 3 and 4 are turned on, the clutch/brake 1 is turned on. In addition, if a failure occurs in the electromagnetic 3-way valve or pressure switch during this process, the press will not be able to operate, and if the electromagnetic 3-way valve or pressure switch is turned off during press operation, the press machine will stop immediately. .

When the press machine is operating normally, the fixed position stop rotary cam switch is activated and the second
Turn off the solenoid 3-way valve 4. Then, the air that had been fed into the air chamber of the clutch/brake 1 is discharged into the atmosphere via the second electromagnetic three-way valve 4, and the press machine stops at a fixed position. Furthermore, the second
Since the first electromagnetic three-way valve 3 is also turned off almost in synchronization with the electromagnetic three-way valve 4, the air in the air chamber of the clutch/brake 1 is also exhausted through this electromagnetic three-way valve 3.

On the other hand, the signal from the rotary cam switch
When the first electromagnetic three-way valve 4 is not turned off, the first electromagnetic three-way valve 3 is also not turned off, so the press machine can continue to operate. In this way, when the press machine reaches about 10 degrees past the home position, the conventionally known double drop prevention proximity switch activates the double drop prevention device to stop the press machine. Therefore, like this 2
When the drop prevention device is activated, it means that the second electromagnetic three-way valve 4 is out of order.

Note that the control method (flow chart) during operation of the press machine and when a failure occurs is not necessarily limited to the embodiment.

As explained above, the present invention has a simple configuration in which two electromagnetic three-way valves and two pressure switches are connected in series. The speed of air inflow and outflow can be increased when the brake is turned on and off and when an abnormality occurs. In addition, since it uses a general-purpose electromagnetic three-way valve with a simple structure and low cost, the cost of the control valve can be reduced, and parts can be easily obtained, improving the workability of maintenance and inspection of the control valve. can.

Furthermore, even if the valve fails in a state where it cannot exhaust air, it can be accurately detected, and at the same time, since the output of the pressure switch changes every time the valve opens and closes (press cycle), it can also detect abnormalities in the pressure switch. I can do it.

[Brief explanation of drawings]

FIG. 1 is a pneumatic circuit diagram of essential parts showing an embodiment of the present invention. Figure 2 is a flowchart when a failure occurs. FIG. 3 is a flowchart during press operation. 1...Clutch/brake, 2...Air piping, 3,
4... Solenoid 3-way valve, 5, 6... Pressure switch.

Claims (1)

[Claims] 1. In a press machine equipped with a clutch/brake that transmits power only when air is supplied, a first electromagnetic three-way valve whose first port is connected to an air supply source; a second electromagnetic three-way valve having a first port connected to a second port of the three-way valve; an air chamber of a clutch/brake connected to a second port of the second electromagnetic three-way valve; a first pressure switch that detects the pressure of an airline extending from a second port of the electromagnetic three-way valve to a first port of the second electromagnetic three-way valve;
a second pressure switch for detecting the pressure of the airline extending from the second port of the three-way valve to the air chamber, and the third ports of both the electromagnetic three-way valves are each opened to the atmosphere. Mechanical clutch/brake device.