JP2001151473A - Electric hosting machine with braking state monitoring function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric hoisting machine easy to recognize a braking state also from the outside by automatically detecting the braking state of a brake by the hoisting machine itself, resolving the difficulty of recognizing the lowering of braking performance of the brake quantitatively and automatically in a conventional way. SOLUTION: This purpose is attained by providing a braking detection means, a number of revolution detection means, a brake slip amount comparison arithmetic means, a numerical display means, an external output means and an operation limiting means, in an electric hoisting machine. Safety is improved by automatically detecting a braking state of the brake by the hoisting machine itself and monitoring a stopping distance. A performance lowering state of the brake can be quantitatively recognized and maintainability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a lifted load,
The present invention relates to an electric hoist that is held by frictional force of a braking brake mechanically directly connected to a motor.

[0002]

2. Description of the Related Art Conventionally, regarding the determination of the quality of a braking state of a brake, a stopping distance at the time of performing a stopping operation is visually observed and roughly determined, and a stopping distance from a braking start point to a stop is measured. For example, a method of detecting the stopping distance from the outside of the hoist and determining whether the braking state is good or bad has been adopted. In addition, when to replace the brake brake parts, the wear amount is measured and compared with a predetermined value.

[0003]

According to the above-mentioned prior art, no quantitative and automatic judgment is made on the braking state of the brake. In the case where the braking state changes every moment due to the change of the state, it is difficult to determine whether the braking state is good or not, and it is difficult to sequentially detect the braking failure and avoid the abnormal state. In addition, the time to replace the brake brake component is determined by measuring the amount of wear and comparing it with a predetermined value, and does not directly determine a decrease in braking performance.

An object of the present invention is to provide an electric motor capable of automatically detecting a braking state of a brake by a hoisting machine itself, judging a braking failure, restricting the operation, and preventing an increase in the stopping distance beyond the current level. An object of the present invention is to provide a hoist. In addition, in order to quantitatively grasp the performance degradation state of the brake brake parts, the slip amount during the braking operation of the brake is displayed as a numerical value, and the numerical value is managed during maintenance and inspection. It is an object of the present invention to provide an electric hoist capable of easily and quantitatively grasping the condition.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to detect a braking operation of a brake in an electric hoist in which a suspended load is held by frictional force of a brake brake mechanically directly connected to a motor. Brake braking detection means, rotation number detection means for detecting the actual rotation number of the motor, and during the braking operation detected by the brake braking detection means, the actual rotation number of the motor detected by the rotation number detection means, A brake slip amount comparison / calculation means for comparing the slip amount of the brake brake with a predetermined value; a numerical value display means for displaying a numerical value of the slip amount detected by the brake slip comparison / calculation means; Means for outputting a warning when a detected value exceeds a predetermined value, a brake slip; If the detected value in the amount comparison calculation means exceeds a predetermined value, it is achieved by providing an operation restriction means for restricting the operation of the hoisting machine.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a functional configuration of an electric hoist having a braking state monitoring function when driven by an inverter.

In FIG. 1, 1 is a suspended load, 2 is a wire rope, 3 is a winding drum, and 4 is a speed reduction mechanism. Reference numeral 5 denotes an encoder serving as rotation speed detecting means, 6 denotes a braking brake that holds a load by frictional force, 7 denotes a motor, 8 denotes a controller that performs collective control by a microcomputer, and a digital display 8a that serves as numerical display means. And a relay contact output 8b serving as an external output means. 9 is an inverter for driving the motor 7, and 10 is a push button operation switch. In the case of driving by an inverter, the encoder 5 and the controller 8 are provided as a standard configuration, and the present invention can be realized without requiring the addition of a special mechanism.

Next, a series of operations will be described with reference to FIG.

The start and stop of various operations are input to the controller 8 by the push button operation switch 10. When the controller 8 receives the operation command, the controller 9 responds accordingly.
To the control signal. In the case of starting, after confirming the frequency output of the inverter 9, a voltage is applied to the brake 6 at a specified timing to release the constraint of the motor 7 and other mechanical units. In the case of a stop, after confirming the frequency output of the inverter 9, the voltage to the brake 6 is cut off at a specified timing, and the mechanism including the motor 7 is restrained. The inverter 9 drives the motor 7 by applying a frequency-converted voltage according to the control signal. The rotation of the motor 7 is transmitted to the mechanically connected reducer 4, and after being decelerated,
By rotating the winding drum 3, winding the wire rope 2,
Raise and lower the suspended load 1. The rotation transmitted to the speed reducer 4 is detected by the encoder 5, input to the controller 8, and given to the microcomputer. As described above, this series of operations are all controlled by the microcomputer of the controller 8, and the state of the brake 6 and the operation control of the inverter 9 are also managed collectively.

FIG. 2 is an explanatory view of a braking brake mechanism of an embodiment of the electric hoist having a braking state monitoring function.

In FIG. 2, 11 is an end plate, 1
2 is a brake wheel, 13 is a brake disc, 14 is a brake gap adjusting screw, 15 is a brake lever,
6 is a solenoid fixed core, 17 is a solenoid movable core,
Reference numeral 18 denotes a motor shaft.

Next, a series of operations of the brake mechanism will be described with reference to FIG.

The state indicated by the dotted line in the figure indicates a stopped state. Brake wheel 1 located at the end of motor shaft 18
Reference numeral 2 designates a surface of the end plate 11 as a friction surface, and a braking force is applied by a brake disc 13 via a brake lever 15 by a brake pressing force of a spring and is restrained.

The solid line in the figure indicates the open state. When a voltage is applied to the solenoid fixed core 16, the solenoid movable core 17 is sucked downward by the solenoid suction force,
The pressing of the brake lever 15 is released by the link mechanism, and the brake wheel 12 is released. At the time of braking, as in the above-described stopped state, when the application of voltage to the solenoid fixed core 16 is stopped, the solenoid movable core 17 is released by the brake pressing force of the spring, and at the same time, the brake pressing force is transmitted to one end of the brake lever 15. The leverage causes a large force to press the fulcrum of the brake disc 13 to generate a braking torque by the frictional force, thereby restraining the motor. The frictional force fluctuates depending on the change in the frictional area and the temperature of the frictional surface. Generally, the frictional force decreases as the frictional area decreases and the temperature of the frictional surface increases. The brake gap is the brake wheel 12
The gap must be maintained at a constant interval in order to increase the wear caused by the wear of the brake gap and to reduce the braking force. The slip amount detected by the present invention can be adjusted manually while checking the amount of slip. However, a mechanism for automatically adjusting the amount of movement of the solenoid movable core 17 can also be provided.

FIG. 3 is a time chart at the time of brake braking of one embodiment of the electric hoist having the braking state monitoring function.

In FIG. 3, when the power supply to the motor is cut off from the rotating state of the motor and brake braking is started, the motor changes from the rotating state to the stopped state through the slipping state due to frictional force. In the present invention, the microcomputer of the controller 8 in FIG. 1 uses the encoder 5 to detect the number of revolutions during the slip state until the rotation of the motor 7 stops from the start of braking. The start of braking can be grasped because the microcomputer of the controller 8 also controls the brake 6. The detection process is performed every time the braking operation is performed, and the detected value is displayed on the digital display 8a through a calculation process. The values to be displayed include the number of rotations, the braking distance, and the ratio to the distance moved per unit time at the rated speed. Since the slip amount increases due to the increase in the brake gap due to wear of the brake wheel 12 and the like, the numerical value increases. By managing the display value at the time of inspection, a decrease in the braking force can be recognized, so whether adjustment or replacement is necessary. Can be determined.

FIG. 4 is a flowchart showing an operation of the electric hoist having the braking state monitoring function according to the embodiment when the braking distance is abnormal.

In FIG. 4, first, as described above, the number of rotations from the start of braking to the stop of rotation is detected. Next, the detected value is compared with a predetermined value in a range where a sufficient braking force can be secured. If it does not exceed the predetermined value, it is determined that the operation is normal, and the operation is not restricted. If the default is exceeded,
The operation is stopped, a warning is output to the outside, and the stopped state is maintained until the reset operation is received regardless of the operation instruction input. In the present invention, the relay contact output 8b in FIG. 1 is used as an external output, which is effective when a hoist is incorporated in a system and used. As other methods, there are a method using sound, a method using light projection, and the like. The reset operation includes, for example, the operation of turning on the power again, the operation of the push-button operation switch 10 in FIG. 1, and the operation of directly operating the controller 8. The operation shown in FIG. 4 is performed by the microcomputer of the controller 8 in FIG. 1, and is automatically processed each time a braking operation is performed. This is due to the
For example, some foreign matter adheres to the braking surface of the brake wheel 12 and a normal frictional force cannot be obtained at the time of braking, or the friction coefficient decreases due to an increase in the temperature of the braking surface when used frequently. It functions effectively when the braking distance suddenly increases, for example. It is important to determine a default value to be compared with the detected value so as to determine an appropriate value within a range where a sufficient braking force can be secured. For example, when the braking distance is used, the controller 8 automatically determines the distance of 1% of the distance moved per minute at the operating speed of the hoist when braking is performed as a default value. It is also possible to adjust manually. In this case, if a value that is far apart is input, the function will not work effectively and a dangerous state will be caused. The controller 8 regulates the distance to 1% of the upper limit.

[0020]

The present invention is as described above. The hoisting machine itself detects the braking state of the brake, judges the braking failure, restricts the driving, and prevents the extension of the stopping distance more than the present. This has the effect of improving safety. Also,
At the time of maintenance and inspection, it is possible to manage the slip amount during the braking operation of the brake by numerical values, and it is possible to quantitatively grasp the performance degradation state of the brake brake parts. Therefore, it is possible to appropriately determine the time for replacing parts,
This also has the effect of improving maintainability.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of an embodiment of an electric hoist having a braking state monitoring function.

FIG. 2 is an explanatory view of a braking brake mechanism of an embodiment of the electric hoist having a braking state monitoring function.

FIG. 3 is a time chart at the time of brake braking of an embodiment of the electric hoist having the braking state monitoring function.

FIG. 4 is a flowchart of an operation of the electric hoist having the braking state monitoring function according to the embodiment when the braking distance is abnormal.

[Explanation of symbols]

1 ... suspended load, 2 ... wire rope, 3 ... winding drum, 4
... Deceleration mechanism, 5 ... Encoder, 6 ... Brake brake, 7 ...
Motor, 8: Controller, 8a: Digital display, 8b: Relay contact output, 9: Inverter, 10: Push button operation switch, 11: End plate, 12: Brake wheel, 13: Brake disc, 14: Brake gap adjusting screw , 15 ... brake lever, 16 ... solenoid fixed core, 17 ... solenoid movable core, 18 ...
Motor shaft.

Claims (4)

[Claims] 1. An electric hoist that holds a lifted load by a frictional force of a braking brake mechanically directly connected to a motor, wherein a brake braking detecting means for detecting a braking operation of the braking brake, and an actual motor of the motor. A rotational speed detecting means for detecting a rotational speed, and an actual rotational speed of the motor detected by the rotational speed detecting means during a braking operation detected by the brake braking detecting means, i.e., a slip amount of the braking brake is predetermined. A brake slip amount comparison / calculation means for comparing with the calculated value, a numerical value display means for displaying a numerical value of the slip amount detected by the brake slip comparison / calculation means, and a detected value determined by the brake slip comparison / calculation means. The external output means for outputting a warning when the value exceeds the value, and the detected value in the brake slip comparison calculation means If a predetermined value is exceeded,
An electric hoist with a braking state monitoring function, comprising an operation restricting means for restricting operation of the hoist. 2. The electric hoist with a braking state monitoring function according to claim 1, wherein the electric hoist is driven by an inverter. 3. An electric hoist with a braking state monitoring function according to claim 1, wherein the external output means is a contact output such as a relay. Machine. 4. The electric hoist according to claim 1, wherein the external output means is provided by voice or light. .