JP2735005B2 - Drive control device for hoisting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for a hoisting device. The drive control device of the hoist according to the present invention is applied to a drive control device of a winch such as a drawworks of an excavator.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a drilling device used for drilling a water well, a hot spring well, a geothermal well, an oil / gas well, an earthquake observation well, or various wells. This excavator 100
Has a mast 101 built on the ground. On the top of the mast 101 is a crown block 1 which is a fixed pulley.
02 is attached. In the vicinity of the base of the mast 101, a drawworks 103 as a hoisting device is provided. The base end of the winding work line 104 is connected to the drum of the draw works 103. The tip side of the work line 104 is Draw Works 1
03 is pulled out to the crown block 102 from the drum. Further, the work line 104 makes several round trips between the crown block 102 and a hook block 105 which is a moving pulley provided below the crown block 102. Hook block 105 is drill strings 1
06 total weight. Below the drill strings 106 are provided a drill collar 107 and a drill bit 108 to which a downward force is applied by the weight of the drill collar 107. The drill strings 106 are rotated by driving the rotary 109. The rotary 109 is driven by a rotary drive of the drawworks 103.

When the drill strings 106 and the like are lifted from the inside of the mine, the work line 104 is wound by driving the drum of the draw works 103 to rotate. When lowering the drill strings 106 etc. into the mine, the motor 2 was stopped or the clutch of the drum was operated while rotating in the same direction as when lifting the pipe, and the motor 2 and the rotating part of the drum were separated and simultaneously free. By intermittently operating the operation handle of the drum brake for applying a brake to the rotation of the drum, the drum string is lowered by its own weight such as the drill string 106. When performing drilling work, use drill strings 1
06 was dropped into the mine, and then the rotary 109 was driven by the drawworks 103, and the drill strings 1
The bit 108 is rotated via 06.

As a drive source of the draw works 103, a diesel engine or a DC motor using a thyristor is used.

[0005]

The drawworks driving source in the conventional excavator has the following problems. That is, a diesel engine has a large noise, a DC motor using a thyristor is expensive, and maintenance of the motor brush takes time and effort.

As means for avoiding such a problem, the present inventors have obtained an idea of using an AC motor using an inverter as a drive source for the drawworks. However, in the case of an AC motor using an inverter, a problem that an inverter trip occurs in an overload region is expected. Inverter trip means that when an overload current flows for a certain period of time or more, the output current from the inverter is cut off to avoid burning of the motor, and the rotation of the motor becomes free. It is expected that overloading will often occur when lifting drill strings and the like. If a trip occurs when lifting the drill strings, etc., the rotation of the AC motor and the rotation of the drawworks drum become free, the winding of the work line is interrupted, and the drum rotates reversely due to its own weight of the drill strings, etc. Falls.

[0007] The present invention relates to a drive control device for a hoisting device having an AC motor controlled by an inverter.
The purpose is to enable stable operation without inverter trip.

[0008]

According to a first aspect of the present invention, there is provided a drive control device for a hoisting device, comprising: an AC induction motor for driving the hoisting device; an inverter unit for controlling the frequency of the AC induction motor; The inverter device section compares the rated torque value that can be generated in the motor with the load torque value required by the load, and detects that the load torque value exceeds the rated torque value for a predetermined time. A control device for regulating the maximum torque value to be generated to a rated torque value.

[0009]

The frequency of the AC induction motor for driving the hoist is controlled by the inverter unit. The control device unit compares a rated torque value that can be generated in the AC induction motor with a load torque value required by the load, and when it is detected that the load torque value exceeds the rated torque value for a predetermined time, the inverter. The maximum torque value that the device generates in the AC induction motor is regulated to the rated torque value.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A drive control device 1 according to an embodiment (hereinafter, this device 1)
Also called. ) Is applied to the drawworks 103 of the excavator 100 as described above. As shown in FIGS. 1 and 2, the present device 1 includes a motor unit 3 having an AC induction motor 2 (hereinafter, also referred to as a motor 2) for driving a hoisting device, and a rotation speed and torque of the motor unit 3. It has a control unit 4 for controlling, a driller operation unit 5 for the driver to operate the draw works, a pressure sensor unit 6 for setting the speed of the motor 2, and the like.

The motor 2 of the motor section 3 is an AC induction motor dedicated to an inverter whose frequency can be controlled by frequency control, and has a cooling fan. The motor unit 3 has a tachometer 7 for detecting the number of rotations of the motor 2. The number of revolutions detected by the tachometer 7 is input to an inverter unit 9 of the control unit 4 described later. The motor unit 3 has a thermistor detection unit that detects the temperature of the motor 2. When the temperature of the motor 2 detected by the thermistor detector indicates an abnormal value, the motor 2 stops operating.

The control unit 4 has an AC power distribution unit 8, an inverter unit 9, and a control unit 10. The AC power distribution unit 8 receives AC power supplied from the outside and distributes the power to the inverter unit 9 and the control unit 10.

The inverter unit 9 includes a control unit 10
, A speed command value (rotational speed command value) and a torque regulation value are input. Based on these values, the inverter unit 9 controls the number of revolutions of the motor 2 and limits the torque generated by the motor 2 to a predetermined regulation value. The rotation speed of the motor 2 is input to the inverter unit 9 from the tachometer 7 of the motor unit 3. The inverter unit 9 controls the actual rotation value and the actual load torque value of the motor 2 by the control unit 10.
Give to.

The control unit 10 includes an A / D unit 11 and a D / D
It has an A section 12, an IO section 13, an operation section 14, and a storage section (not shown). During the operation of the motor 2, the motor 2
Are input from the inverter unit 9 to the control unit 10. Further, the rotation speed command value set by the rotation speed setting unit 15 of the driller operation unit 5 and the rotation speed command value set by the pressure sensor unit 6 operated by the foot-operated pedal are input to the control device unit 10. Is done.

The control unit 10 supplies the input rotation speed command value to the inverter unit 9 and controls the motor 2 to rotate at the specified rotation speed. Further, the rotation nest command value and the actual number of revolutions input to the control unit 10 are compared in the arithmetic unit 14, and the control unit 10 performs feedback control of the inverter unit 9 based on the difference.

The arithmetic unit 14 of the control unit 10 calculates an actual load torque value input from the inverter unit 9 and a rated torque value (continuous output torque value) that can be continuously generated by the motor 2 by the inverter unit. And always compare. When the actual load torque value exceeds 100%, the maximum torque generated by the inverter unit 9 in the motor 2 is limited to a predetermined torque regulation value in accordance with a predetermined procedure.

In the graph showing the relationship between the generated torque and the number of revolutions of the motor 2 shown in FIG. 3, solid lines A and B indicate the short-time rated torque value of the motor 2, and solid line D indicates the continuous rated torque value of the motor 2. ing. As shown in FIG.
After starting the operation, the torque regulation value is set to 150% which is the maximum value of the short-time rated torque value (step 1).
When the actual load torque value exceeds the rated torque value of 100% or 150% (step 2), the torque regulation value down timer starts measuring time (step 3). If the predetermined time is measured (step 4), the maximum output torque value of the motor 2 is set to 100% or 80% (15%) of the continuous rated torque value.
0 rpm or less) (step 5).

Specifically, the number of rotations of the motor 2 is 0 to 15
When the torque of 150% or more continues for 15 seconds or more in the range of 0 rpm, the control unit 10 controls the inverter unit 9 so that the torque of the motor 2 is limited to the regulation value of 80%.

When the torque of 100% or more continues for 30 seconds or more in the range of the rotation speed of the motor 2 from 0 to 150 rpm, as shown by the solid line C in FIG.
Controls the inverter unit 9 so that the torque of the motor 2 is limited to the regulation value of 80%.

The rotation speed of the motor 2 is 150 to 2400 rpm
150% or more in the range of m
If it lasts for more than one second, the control unit 10 controls the inverter unit 9 so that the torque of the motor 2 is limited to the regulation value of 100%.

The rotation speed of the motor 2 is 150 to 2400 rpm
100% or more in the range of m
If it lasts for more than one second, the control unit 10 controls the inverter unit 9 so that the torque of the motor 2 is limited to the regulation value of 100%.

The data indicating the relationship between the generated torque of the motor 2 and the rotational speed as shown in FIG. 3 and the processing procedure of the data as described above are stored in a storage unit (not shown).
The data is read out to the arithmetic unit 14 as needed. Further, the control device section 10 has the torque regulation value down timer necessary for measuring the time in the above processing.

The driller operation section 5 has an operation section 17 and a display section 18. The operation unit 17 sets a rotation speed of the motor 2 in a range of 0 to 2400 rpm.
, An emergency stop push button 19, a buzzer stop push button 20, and a changeover switch 21 for switching between drawworks and rotary driving. The display unit 18 has a tachometer 22, a torque meter 23, and an indicator light 24.
The “inverter power supply” of the indicator light 24 is the inverter unit 9
Lights when the power is turned on. "Blower power"
Lights when the power of the cooling fan of the motor 2 is turned on. “Inverter running” is lit when the motor 2 is rotating by the inverter unit 9. “Max torque is being output” means that the load torque is required to be 150%, and the inverter unit 9 is lit while the motor 2 is operating at a torque of 150%. The “torque regulation timer” is turned on when the torque regulation timer measures the time when the load torque exceeds 100% or 150%. “Failure” means that this device 1
Lights when any electrical component fails. "DW mode"
Lights when the changeover switch 21 is switched to the draw works operation. The “RT mode” is turned on when the changeover switch 21 is switched to a rotary operation. "Constant output area" is 1500 rpm to 2400 rpm
Lights when the motor 2 is rotating during m. The "torque command MAX" is turned on when the torque regulation value in the inverter unit 9 is set to 150%. “Torque command regulation” means that the torque regulation in the inverter unit 9 is 80%
Or, it lights when set to 100%. “Inverter failure” is lit when the inverter device section 9 has failed.

The pressure sensor unit 6 has a foot pedal and a pressure sensor for detecting an air pressure that changes in proportion to the depth of depression of the foot pedal. The pressure sensor changes the output voltage in proportion to the magnitude of the air pressure. This output voltage becomes an analog signal corresponding to the rotation speed command value of the motor 2. Pressing the foot pedal increases the rotation speed.

The pressure switch 30 outputs a contact signal when the pressure sensor section 6 detects a pressure equal to or higher than the pressure corresponding to the lower limit of the number of revolutions required for the drawworks operation. This signal is used as a confirmation signal indicating that the foot pedal has been securely depressed. That is, only when both the rotation speed command value from the pressure sensor unit 6 and the contact signal from the pressure switch 30 are input to the control device unit 10, the control device unit 10 outputs the rotation speed command value to the inverter device. Part 9
To control the rotation speed of the motor 2.

The pressure sensor of the pressure sensor unit 6 may output an analog signal due to air pressure leak in the pressure sensor unit 6 even though the foot pedal is not depressed. Further, an analog signal may be output according to a temperature change in the pressure sensor unit 6. However, since the present device 1 has the pressure switch 30 as described above, the rotation is performed only when the operator actually presses the foot pedal of the pressure sensor unit 6 to increase the rotation speed. The number is controlled.

The operation of the apparatus 1 will be described. At the time of lifting work for lifting drill strings and the like from the mine, the changeover switch 21 of the driller operation unit 5 is set to the draw works side. The rotation speed of the motor 2 is set by the pressure sensor unit 6.
Foot pedal and rotation setting part 1 of driller operating part 5
5 is possible. The number of revolutions of the motor 2 is determined by the set value in the pressure sensor unit 6 and the number of revolutions setting unit 1.
5 is the larger of the set values.

The torque regulation value when the motor 2 is driven is determined when the rotation speed is set by the foot pedal of the pressure sensor unit 6 or when the rotation speed is set by the rotation speed setting unit 15 of the drilling operation unit 5. Different. When the rotation speed is set by the foot pedal of the pressure sensor unit 6, fine adjustment of the rotation speed is not possible, and the rotation speed is relatively rough. Therefore, the torque regulation value is the maximum value of the short-time rated torque value. It shall be 150%. When the actual load torque value exceeds the rated torque value of 100% or 150%, the torque regulation value down timer operates to reduce the torque regulation value after a predetermined time.

When the number of revolutions is set by the number of revolutions setting unit 15 of the drilling operation unit 5, there is a case where the lifting operation is stable and the actual load torque value of the motor 2 is unlikely to be excessive. In this case, the torque regulation value is set to 100% which is the maximum value of the continuous rated torque value. When the actual load torque value exceeds the rated torque value of 100%, the torque regulation value down timer operates to reduce the torque regulation value after a predetermined time.

During the downcoming work of lowering the drill strings or the like into the mine, the motor 2 is stopped and the clutch of the drum is operated to disconnect the rotating portion of the drum from the motor 2 while the motor 2 is stopped or rotated in the same direction as when the pipe is lifted. While repeatedly operating the mechanical brake, the mine is lowered by its own weight, such as hook blocks and drill strings.

At the time of excavation work, the changeover switch 21 of the drill operating section 5 is set to the rotary side. The setting of the rotation speed of the motor 2 is performed by the rotation speed setting unit 15 of the driller operation unit 5.
Becomes effective, and the setting by the foot pedal of the pressure sensor unit 6 is not accepted. The torque regulation value is set to 100% which is the maximum value of the continuous rated torque value. When the actual load torque value exceeds the continuous rated torque value of 100% when the rotation speed of the motor 2 is in the range of 0 to 150 rpm, the torque regulation value down timer operates and the torque regulation value is reduced to 80% after a predetermined time. Lower.

The drive control device 1 according to the embodiment described above is applied to a drawworks of an excavator.
The drive control device of the present invention can be widely applied to hoists such as various winches.

[0033]

According to the drive control device of the present invention, in a drive control device for a hoisting device having an AC motor whose frequency is controlled by an inverter, when a load torque value exceeds a rated torque value for a predetermined time. Since the maximum torque value generated by the AC motor is regulated to the rated torque value, stable operation without inverter trip can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of an embodiment.

FIG. 2 is a diagram illustrating a part of a configuration of an embodiment and a signal transmission / reception relationship.

FIG. 3 is a diagram illustrating a relationship between a rotation speed and a torque in the motor according to the embodiment.

FIG. 4 is a flowchart showing a procedure of torque control in one embodiment.

FIG. 5A is a front view of a driller operation unit according to one embodiment, and FIG. 5B is an enlarged view of an indicator light in the driller operation unit according to one embodiment.

FIG. 6 is a perspective view of a conventional general excavator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive control device 2 AC induction motor (motor) 9 Inverter control part 10 Control device part 103 Drawworks as a hoisting device

Claims (1)

(57) [Claims] 1. An AC induction motor that drives a hoist, an inverter unit that controls the frequency of the AC induction motor, and a rated torque value that can be generated in the AC induction motor and a load torque value required by a load are compared. And a control unit that regulates the maximum torque value generated by the inverter unit to the AC induction motor to the rated torque value when it is detected that the load torque value exceeds the rated torque value for a predetermined time. Drive control device for the hoisting device.