JPH043753Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) This invention relates to a drive control device for a press machine.

(Prior Art) As an example of a conventional drive control device for a press machine, a solenoid valve is switched and controlled based on a drive command, and a clutch brake is operated or a hydraulic circuit is switched in accordance with the switching control of the solenoid valve. The ram equipped with a punch is lowered toward the die. Further, a limit switch is disposed in the plunger portion of the electromagnetic valve, and an abnormality detection device is attached to the electromagnetic valve for detecting a non-operating state of the electromagnetic valve by not operating the limit switch when energized.

(Problems to be Solved by the Invention) However, in the conventional drive control device for a press machine as described above, the non-operating state of the solenoid valve is detected by a mechanical limit switch. However, the structure is complicated, and if the limit switch becomes abnormal, it becomes impossible to detect the non-operating state of the solenoid valve.

For example, if the solenoid valve has malfunctioned and the limit switch has malfunctioned due to mechanical damage or dust at the work site, the ram may fail even though power is being supplied to the solenoid valve. does not fall, and the abnormal state is not reported. Therefore, if the solenoid valve abnormality is canceled for some reason after this condition,
The ram may lower unexpectedly, creating a safety hazard.

In view of these conventional problems, the object of this invention is to provide a drive control device for a press machine that is easy to configure and free from safety problems.

[Structure of the invention] (Means for solving the problems) In order to achieve the above object, the present invention provides a fluid pressure circuit that connects and disconnects a clutch brake in a press machine. A power supply circuit that supplies alternating current power to a solenoid valve and a coil provided in the solenoid valve compares a preset comparison current with the power supply current after a predetermined period of time has elapsed from the time when the coil is energized, and determines the non-operating state. The device includes a non-operating state detection circuit for detecting the non-operating state, and an abnormality processing circuit for cutting off the power to the power supply circuit when the non-operating state detecting circuit detects the non-operating state.

(Function) In this invention, the non-operating state of the solenoid valve is electrically detected, and abnormality processing such as shutting off the power immediately after detecting the non-operating state of the solenoid valve is performed.

(Embodiment) FIG. 1 is an explanatory diagram showing a drive control device according to an embodiment of this invention together with a press model.

As illustrated, the press is shown as an example of a clamp press.

A ram 5 is connected to the crankshaft 3 of the crank press 1, and a punch 7 is attached to the lower end of the ram 5. A die 9 is arranged below the punch 7,
A plate material (not shown) is punched between the punch 7 and the die 9. A clutch brake 11 is attached to the shaft end 3a of the crankshaft 3.

The clutch brake 11 includes a slider 13 connected to the shaft end 3a by a spline, and a slider 13 connected to the shaft end 3a by a spline.
It has a pulley 15 which is rotated around 3.

Further, a spring 17 is interposed between the shaft end 3a and the slider 13, which normally urges the slider 13 to the left in the figure.

The pulley 15 is always rotated in one direction by a motor (not shown) using a belt (not shown) or the like.

Further, a clutch plate 13a and a brake plate 13b are fixed to the outer peripheral surface of the slider 13, sandwiching a drive plate 15a provided on the end surface of the pulley 15 and a brake fixing plate 19 disposed a little apart from the drive plate 15a. ing.

In the clutch brake 11, the slider 13
is normally biased to the right in the figure, and the brake plate 13b
and the brake fixing plate 19 are in contact with each other,
Crankshaft 3 is ram 5 with the punch lifted.
is stationary. On the other hand, when the slider 13 is inserted into the spring 17 and slid to the left in the figure, the drive plate 15a and the clutch plate 13a are in contact with each other, and the crankshaft 3 lowers the punch 7 relative to the die 9. The ram 5 will be raised and lowered to encourage the driver.

The slider 13 is provided with a cylinder 21 for moving the slider 13. The cylinder 21 is controlled by a hydraulic circuit via a solenoid valve 23.

The solenoid valve 23 has a valve body 23a with 4 ports and 2 positions.
A plunger 23b is connected to the plunger 23b.
Terminals 23e,
A coil 23d connected to 23f is wound.

A power supply circuit 27 that supplies alternating current power to the solenoid valve 23 is connected to the terminals 23e and 23f via a non-operating state detection circuit 25, and these circuits 25 and 27
An abnormality processing circuit 29 is connected between them.

The power supply circuit 27 supplies a power supply voltage to the solenoid valve 23 at the time when the ram 7 is to be lowered.

The non-operating state detection circuit 25 compares the comparison current Is set at the time of energization with the power supply current I, and detects the non-operating state of the plunger 23b. The comparison current Is is set as an intermediate current value between the steady current I ₀₁ in the normal state and the steady current I ₀₂ in the abnormal state shown in FIGS. 2 and 3, and as shown in FIG. If the current current I is larger than the comparison current Is after the stabilization time T ₁ has elapsed after being turned on, it is detected that there is an abnormality, that is, the plunger 23 is not operating. In the figure, T _D is the detection time period. It shows.

The abnormality processing circuit 29 is activated when the non-operating state detection circuit 25 detects an abnormal state, and is a circuit that shuts off the power to the power supply circuit 27 and outputs an abnormality notification using a buzzer or the like as appropriate.

With the above circuit configuration, even though the power is turned on at time t ₀ as shown in FIG. 4a, the solenoid valve 1 is inoperative as shown in FIG. 4b, that is, the plunger 23 If it becomes inoperative, an abnormality is detected by the non-operating state detection circuit 25 after time _T1 as shown in FIG. 4c, and the power is cut off at time _t2 as shown in FIG. 4a.

Here, the time T ₁ is a time of about 0.05 to 0.1 seconds, and the time between times t ₁ and t ₂ is a minute time of about 0.01 seconds.

Therefore, when the solenoid valve 23 is inactive, the power is turned on and the power supply circuit 27 is turned off after a predetermined period of time, so the ram 5 will not descend or rise thereafter, ensuring safety. Become.

In the above embodiment, an example of a crank press is shown, but the same applies to an electromagnetic valve that switches the hydraulic circuit of a hydraulic press to drive the ram 5.

Further, in the above embodiment, an example of a punching press is shown, but the same applies to other presses such as a drawing press, a turret punch press, and a bending press.

This invention is not limited to the above-mentioned embodiment, but can be implemented in other embodiments by making appropriate design changes.

[Effects of the invention] As can be understood from the above description of the embodiment, the present invention is based on an electromagnetic circuit provided in a fluid pressure circuit to a fluid pressure cylinder 21 that connects and disconnects a clutch brake 11 in a press machine. valve 23
, a power supply circuit 27 that supplies alternating current power to a coil 23d provided in this solenoid valve 23, and a
A non-operating state detection circuit 25 detects a non-operating state by comparing a preset comparison current Is and a power supply current I after a predetermined period of time has elapsed since the power is turned on. The abnormality processing circuit 29 shuts off the power to the power supply circuit 27 when a state is detected.

As is clear from the above configuration, in the present invention, the coil 23d of the solenoid valve 23 that controls the connection and disconnection of the clutch brake 11 in the press machine
After a predetermined period of time has elapsed after energization, the comparison current Is and the power supply current I are compared to detect whether the electromagnetic valve 23 is in an inoperative state. In other words, in the present invention, even if a large current flows for startup at the start of energization to the coil 23d of the solenoid valve 23, the comparison current Is is compared with the power supply current I after a predetermined period of time has elapsed. If the above-mentioned large current is not detected and the solenoid valve 23 is operating normally, there will be no problem. and,
When the electromagnetic valve 23 does not operate, a large current flows through the coil 23d even after a predetermined time has elapsed, so the non-operating state can be easily detected and safety can be ensured.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing a drive control device for a press machine according to an embodiment of this invention together with a press model, Fig. 2 is a time chart showing a normal state of current, and Fig. 3 is a time chart showing an abnormal state of current. FIG. 4 is a time chart showing the operation of the above operation control device. 5... Ram, 23... Solenoid valve, 23b... Plunger, 23d... Coil, 25... Non-operating state detection circuit, 27... Power supply circuit, 29... Abnormality processing circuit, I... Power supply current, Is ...Comparison current.

Claims (1)

[Scope of utility model registration request] A solenoid valve 23 provided in a fluid pressure circuit to a fluid pressure cylinder 21 that connects and disconnects a clutch brake 11 in a press machine, a power supply circuit 27 that supplies alternating current power to a coil 23d provided in this solenoid valve 23, and the above-mentioned A non-operating state detection circuit 25 that detects a non-operating state by comparing a preset comparison current Is and a power supply current I after a predetermined period of time has elapsed since the coil 23d is energized;
when the power supply circuit 27 detects a non-operating state.
An abnormality processing circuit 29 for cutting off power to a press machine.