JPH05204429A - Numerical controller - Google Patents

Abstract

PURPOSE:To exactly prevent the drop of a control shaft without using a hydraulic balance mechanism for preventing the drop of the control shaft. CONSTITUTION:This controller is equipped with a control power source disconnection control part 3 which controls a control power source part 6 based on a control power source disconnection command, torque detecting part 8 which detects the torque of a motor which drives the control shaft, and torque data storage part 5 which holds a prescribed torque value for judging that a brake works. When the control power source disconnection command is inputted, a brake control part 2 starts a brake ON, and a shaft control part 7 operates a shaft movement command at a fine speed after the lapse of a prescribed time t2 longer than a time t1 when the brake works. Moreover, the torque detecting part 8 detects the torque value of the motor which drives the control shaft, and a brake ON detecting part 4 compares the torque detection value of the motor detected by the torque detecting part 8 with the torque value stored in the torque data storage part 5, judges that the brake works when the torque detection value is larger, and executes the control power source disconnection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerical control device for controlling a numerically controlled machine tool having a control shaft which falls by gravity without a holding mechanism from the outside when the control power is turned off.

[0002]

2. Description of the Related Art Generally, the Z axis of a vertical machining center,
Since the control axes such as the Y-axis of the horizontal machining center are substantially vertical, when the control power is turned off, the control axes may fall due to gravity unless there is a mechanism for holding the control axes from the outside. For this reason, in a numerically controlled machine tool having a control shaft (for example, a main shaft) that falls due to gravity, a hydraulic balancer for preventing the control shaft from falling is generally used. FIG. 3 is a schematic diagram of a numerically controlled machine tool using a hydraulic balancer. In this numerically controlled machine tool, the rotation of the motor 9 is transmitted to the ball screw 12 to move the spindle head 13 up and down. Then, when the control power is turned off, the spindle head 1 is driven by the fall prevention brake 10 and the hydraulic balancer 11.
It prevents the 3 from falling due to gravity. FIG. 4 is a block diagram showing the configuration of a conventional numerical control device. The numerical control device has a control power supply cutoff command unit 14 for instructing the control power supply to be cut off. The control power supply cutoff command unit 14 controls the fall prevention brake of the spindle head 13.
5 is connected to a control power supply unit 16 that cuts off the control power supply based on a control power supply cutoff command from the control power supply cutoff command unit 14. The control power supply unit 16 controls the axis of the control axis. The part 17 is connected.

Next, the operation will be described. When the control power supply cutoff command unit 14 outputs a control power supply cutoff command when the control power supply is cut off, the brake control unit 1 that performs brake control of the spindle.
Reference numeral 5 denotes an axis control unit 17 that controls the spindle head 13 by turning off the brake release output to start the fall prevention brake and turning off the output of the control power supply unit 16 that supplies control power. The control is also stopped. FIG. 6 is a time chart showing a conventional control power OFF control sequence. According to FIG. 6, when the control power-off command (f) is input, the brake release output (g) and the control power supply are immediately turned off. The holding force (i) of the spindle due to the fall prevention brake is delayed by t1 hours after the control power-off command (f) is input, but the spindle holding force (h) due to the hydraulic balancer has a predetermined value. The holding force is a force (j) that is the sum of the holding force (h) of the hydraulic balancer and the holding force (i) of the fall prevention brake. Even if the control power is turned off immediately after the control power off command (f). , The spindle never falls.

Further, a device for delaying the turning off of the control power supply for a predetermined time after the fall prevention brake is applied instead of the hydraulic balancer and before the control power supply is turned off will be described with reference to FIG. Compared with the block diagram of FIG. 4, the time t1 at which the fall prevention brake starts to operate after the control power off command from the control power off control unit 18 is passed through the delay circuit unit 20 as shown in FIG. The difference is that the control power supply is turned off after a sufficiently large time t4 has elapsed.

[0005]

However, in the numerically controlled machine tool provided with the above-mentioned hydraulic balancer,
With the recent strong demand for space saving of machines, a hydraulic unit for driving a hydraulic balancer is required, which is not suitable for space saving. In the numerical control device including the delay circuit unit 20 described above, the time from when the fall prevention brake is turned on to when the fall prevention brake is activated due to wear of the fall prevention brake or malfunction of the fall prevention brake. If the length becomes longer, the spindle may not be prevented from falling.

The present invention has been made to solve the above problems, and an object of the present invention is to reliably prevent the control shaft from falling without using a hydraulic balancer mechanism for preventing the control shaft from falling. It is to provide a numerical control device.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and includes a control power-off command section for instructing the control power-off, an axis control section for controlling the axis of a control axis, and a control axis. The brake control unit that controls the fall prevention brake, the control power supply unit that cuts off the control power supply based on the control power supply cutoff command from the control power supply cutoff command unit, and the control power supply cutoff command from the control power supply cutoff command unit Control power supply cutoff control unit that controls the control power supply unit, torque detection unit that detects the torque of the motor that drives the control axis, and torque that holds a predetermined torque value for determining that the fall prevention brake is working. And a data storage unit. Then, the control power-off control unit,
When a control power-off command is received from the control power-off command unit, the motor torque value detected by the torque detection unit is compared with the predetermined torque value stored in the torque data storage unit, and the detected motor torque value is the torque data. It is characterized in that the control power supply unit is controlled so as to determine that the fall prevention brake is activated and perform the control power-off operation when the torque becomes larger than the predetermined torque value stored in the storage unit.

[0008]

In the numerical controller according to the present invention having the above-described structure, when the control power-off control unit receives the control power-off command from the control power-off command unit, the torque value and the torque of the motor detected by the torque detection unit are detected. The predetermined torque value stored in the data storage unit is compared, and if the detected torque value of the motor becomes larger than the predetermined torque value stored in the torque data storage unit, it is determined that the fall prevention brake is working. The control power supply is controlled to perform the control power-off operation, and the control axis control power supply is turned on after the control axis fall prevention brake is activated.
FF to prevent the control shaft from falling.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a numerical controller according to the present invention. As shown in FIG. 1, the numerical control device has a control power-off command unit 1 that generates a control power-off command by a control power-off operation. The control power-off command unit 1 includes a control power-off command. A brake control unit 2 that applies a fall prevention brake to the control axis based on a control power-off command from the unit 1, and a control power-off control unit 3 that executes a control power-off in response to a control power-source command and a brake ON detection signal. And a brake ON detection unit 4 that receives a control power-off command and compares the torque value from the torque detection unit 8 with the torque value from the torque data storage unit 5 to detect whether the fall prevention brake is effective, An axis control unit 7 that controls the axis of the axis is connected. Then, the control power-off control unit 3 turns on the brake.
The detection unit 4 and the control power supply unit 6 that supplies control power to the axis control unit 7 are connected, and the brake ON detection unit 4 stores a torque value for determining that the brake is applied as internal data. The torque data storage unit 5 and the torque detection unit 8 that detects the torque value of the motor that drives the control shaft are connected.

Next, the operation of this embodiment will be described with reference to the time chart of FIG. When the control power-off command is output from the control power-off command unit 1, the brake control unit 2 first receives the control power-off command (FIG. 2A) and then first outputs the brake release (FIG. 2B). ) OFF to start the fall prevention brake ON. Since the holding force of the control shaft (FIG. 2 (e)) due to the application of the brake appears after the elapse of t1 time, the shaft control unit 7 starts rotating the shaft at a minute speed (Va) after the elapse of t2 time that is larger than t1. Send a move command. As a result, the torque value of the motor (FIG. 2C) increases because the axis movement command is issued while the fall prevention brake is in effect, and the torque detection unit 8 detects the torque value of the motor that drives the control axis. Then, the detected torque value is output to the brake ON detection unit 4. Then, the brake ON detection unit 4 compares the detected torque value of the motor detected by the torque detection unit 8 with the torque value (τa) stored in the torque data storage unit 5, and the detected torque value becomes larger. When it is determined that the braking of the control axis is in effect, a brake ON signal is output to the control power-off controller 3. Further, the control power-off control unit 3
Executes the control power-off at time t3 in response to the brake ON signal from the brake ON detector 4.

[0011]

The torque value of the motor is compared with the predetermined torque value stored in the torque data storage section, and if the detected torque value of the motor becomes larger than the predetermined torque value stored in the torque data storage section, a drop occurs. Since the control power is cut off when it is judged that the prevention brake is working, a hydraulic balancer for preventing the control shaft from falling is not required, the number of parts can be reduced, and space and cost can be reduced. You can Further, even if the time from when the fall prevention brake is applied until the brake is activated becomes long due to wear and malfunction of the fall prevention brake of the control shaft, the fall of the control shaft can be reliably prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a numerical control device according to the present invention.

FIG. 2 is a time chart showing the operation of the present invention.

FIG. 3 is a diagram showing a schematic configuration of a conventional numerically controlled machine tool.

FIG. 4 is a block diagram showing a configuration of a conventional numerical control device.

FIG. 5 is a block diagram showing a configuration of a conventional numerical control device.

FIG. 6 is a time chart showing a conventional operation.

FIG. 7 is a time chart showing a conventional operation.

[Explanation of symbols]

 1 Control power supply off command unit 2 Brake control unit 3 Control power supply off control unit 4 Brake ON detection unit 5 Torque data storage unit 6 Control power supply unit 7 Axis control unit 8 Torque detection unit

Claims (1)

[Claims] 1. A control power-off command section for commanding a control power-off, an axis control section for controlling a control axis, a brake control section for controlling a fall prevention brake of the control axis, and a control power-off command. In the numerical control device that has a control power supply unit that cuts off the control power supply based on the control power supply cutoff command from the control unit, and prevents the control axis from falling by the fall prevention brake when the power supply is turned off, the control power supply cutoff command unit In order to determine that the control power-off control unit that controls the control power-supply unit based on the control power-off command from the controller, the torque detection unit that detects the torque of the motor that drives the control axis, and the fall prevention brake are working. And a torque data storage unit that holds a predetermined torque value of, and the control power-off control unit receives a control power-off command from the control power-off command unit and a torque value of the motor detected by the torque detection unit. To If the Kudeta storage unit compares the predetermined torque value for storing the torque value of the detected motor becomes larger than a predetermined torque value stored in the torque data storage unit,
A numerical control device characterized by controlling a control power supply section so as to perform a control power-off operation upon determining that a fall prevention brake is working.