KR20020061098A - Driving apparatus for index table of vertical universal milling machine - Google Patents

Abstract

PURPOSE: A device for driving a partitioned table of a vertical universal milling machine is provided to localize a partitioned table, to reduce the unit cost of the partitioned table, and to obtain high output even at a low speed by using an inexpensive three-phase induction motor of which speed is controlled through vector controlling. CONSTITUTION: A device for driving a partitioned table of a vertical universal milling machine comprises a controller consisting of an AC/DC converter(11) for converting three-phase AC power to single-phase DC power, a microprocessor(14) for controlling the rpm and output torque of the three-phase induction motor by a vector control program, and a control unit for amplifying a signal by a power amplifier(12), a three-phase induction motor(30) for rotating a partitioned table(40) by 5 degrees per 1 rotation of a worm, and an encoder(20) for compensating the rpm of the three-phase induction motor and outputting the compensated value to the microprocessor. By controlling the speed of the three-phase induction motor via the controller, output torque is controlled precisely.

Description

Split apparatus for index table of vertical universal milling machine

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a split table driving apparatus of a vertical universal milling machine, and more particularly, to a split table driving of a vertical universal milling machine in which a three-phase induction motor speed controlled by a vector control method is used as a driving source of a split table instead of a servo motor. Relates to a device.

In general, the manufacturing industry that produces various products by using machinery or apparatus is a key industry that is the basis of national economic development. The machinery industry is the most important production material industry among the manufacturing industries, and forms the basis of industrialization. have.

Various machines used in the mechanical industry are called machine tools. Machine parts machined by machine tools are assembled together to make various machines and devices, so machine tools are sometimes called 'machine making machines'. Therefore, it can be said that machine tools require higher productivity and precision than any other machines.

Milling machine is a machine tool that rotates a cutting tool called a milling cutter with several cutting edges and feeds it to a fixed position on a table. In addition to cutting, it is a machine tool with a very wide range of applications that can efficiently cut screws, gears and cams.

Vertical universal milling machine is a type that the spindle head of a vertical milling machine can turn, and is used for dividing a workpiece at an arbitrary angle, making a gear, cutting a tool, and the like.

Since the table is called an index table, the partition function is an important factor because the work to be loaded into the partition table once and the multi-faceted machining must be performed more quickly and more accurately.

Although the angle of division is in each stage, the high resolution ability is becoming more and more advanced at the center of 5 °, and the pin type was common in the age of division when the number of divisions was small, but as the number of divisions increased, the demand for high accuracy increased. Coupling is widely used.

The rotary mechanism of this partition table uses worms and worm wheels (worm gears), and a servo motor has been used as a driving source. The worm and the worm wheel are for rotating the partition table on which the work is placed, and the servo motor is for driving the worm and the worm wheel, and is mainly used for controlling speed and positioning.

The servomotor has been used for the split table of the conventional universal milling machine. The servomotor is mainly dependent on imports, and the unit cost is very high, thereby increasing the unit price of the product, and thus using manual jigs for various processes. It has been a problem that not only requires skilled skills, but also causes some errors depending on the person, and has a relatively low accuracy. In addition, the precision of the workpiece may be reduced by repeated setting, and the defect rate is high compared to the machining time, thereby causing a cost increase of the product.

The present invention is to solve the above problems, in particular, by using a low-cost three-phase induction motor whose speed is controlled by a vector control method instead of a servo motor as a drive source for rotating the partition table of the vertical universal milling machine. Its purpose is to localize while lowering the unit price, and at the same time to obtain high output even at low speed.

An object of the present invention described above is a partition table of a vertical universal milling machine for machining a workpiece placed thereon by rotation of a split table, the partition table comprising: an AC / DC converter for converting three-phase AC power into single-phase DC power; A microprocessor to which the converted single-phase DC power supply is applied and a built-in vector control program controls the rotational speed and output torque of the three-phase induction motor; A DC / AC converter for converting the single-phase DC power output from the AC / DC converter into a three-phase AC power; A control device comprising a power amplifier for amplifying the signal to control the DC / AC converter with the microprocessor control signal; A three-phase induction motor for rotating the partition table by 5 ° per one rotation of the worm by the vector control signal of the microprocessor; The rotation speed of the three-phase induction motor is corrected for dividing angle adjustment and position adjustment of the partition table, and is achieved by configuring an encoder for outputting the correction value to the microprocessor.

1 is a circuit block diagram of a split table driving apparatus of a vertical universal milling machine of the present invention.

Explanation of symbols on the main parts of the drawings

10: controller 11: AC / DC converter

12: power amplifier 13: DC / AC converter

14 microprocessor 20 encoder

30: three-phase induction motor 40: split table

Hereinafter, the configuration and operation of the present invention will be described in detail with reference to the accompanying drawings. 1 is a circuit block diagram of a split table driving apparatus of a universal milling machine of the present invention.

The present invention relates to a split table of a vertical universal milling machine for processing a workpiece placed thereon by rotation of a split table, comprising: an AC / DC converter (11) for converting a three-phase AC power source into a single-phase DC power source; A microprocessor 14 to which the converted single-phase DC power is applied and which has a vector control program to control the rotational speed and output torque of the three-phase induction motor 30; A DC / AC converter 13 for converting single-phase DC power output from the AC / DC converter 11 into three-phase AC power; A control device comprising a power amplifier 12 that amplifies a signal so as to control the DC / AC converter with the microprocessor control signal; and warms the partition table 40 by a vector control signal of the microprocessor 14. A three-phase induction motor 30 rotating by 5 ° per one revolution; The encoder 20 is configured to correct the number of revolutions of the three-phase induction motor 30 to adjust the dividing angle and position of the dividing table 40, and output the correction value to the microprocessor 14. .

Here, the encoder 20 is preferably used that has a high resolution in order to hold up to a minute angle when the worm, which is a rotation mechanism of the partition table 40, rotates once.

The present invention relates to a drive device for rotating the partition table 40. In the technical configuration of the drive device as described above, the present invention provides a three-phase induction motor 30 and the three-phase induction motor ( It uses vector control technology to precisely adjust angle and position through speed control.

This vector control is a method for controlling the output torque of the three-phase induction motor 30 at high speed. Because of the vector control method, high output torque is generated even at low speed, so that position control is easy. Therefore, it is possible to improve the problem that high output cannot be realized at low speed, which is a disadvantage of the conventional servomotor.

Meanwhile, an AC / DC converter 11 for converting three-phase AC into single-phase DC and a power amplifier 12 for amplifying a signal to control the DC / AC converter 13 with a microprocessor control signal and the AC / The three-phase induction motor 30 is controlled by a control device 10 composed of a DC / AC converter 13 for outputting direct current output from the DC converter 11 to three-phase alternating current and a microprocessor 14 incorporating vector control software. By controlling the speed of), the output torque can be precisely controlled.

Here, the speed, the rotation speed and the position value of the three-phase induction motor 30 detected by the encoder 20 are input to the microprocessor 14.

Detailed technical operation of the driving device of the split table of the universal milling machine of the present invention as described above will be described with reference to FIG.

When power is supplied to operate the workpiece after the workpiece is placed on the table 40 of the universal milling machine, the three-phase AC power is converted into a single-phase DC power through the AC / DC converter 11, and the single-phase DC is thus converted. Power is applied to the microprocessor 14 while to the DC / AC converter 13.

The single-phase DC power output from the AC / DC converter 11 is converted into a three-phase AC power again through the microprocessor control signal and the DC / AC converter 13.

That is, in order to convert the operating frequency of the three-phase AC power supply to the three-phase induction motor 30 to convert the three-phase AC power to a single-phase DC power using the AC / DC converter 11 and then again the DC / AC converter Using 13, the voltage and the operating frequency are converted and supplied to the three-phase induction motor 30.

Here, the microprocessor 14 has a vector control program that enables vector control and controls it according to the vector algorithm.

The encoder 20 detects and corrects the rotation speed and position of the three-phase induction motor 30, and continuously feeds back the correction value to the microprocessor 14. The encoder 20 has high resolution and can detect and correct minute angles when the worm rotates once.

By the feedback value thus fed back, the microprocessor 14 controls the rotational speed and output torque of the three-phase induction motor 30 according to the algorithm of the vector control program embedded therein. By the above vector control program, high output torque can be realized at low speed. The three-phase induction motor 30 controlled based on the control signal to the microprocessor 14 drives the worm and the worm wheel (worm gear), which are rotating mechanisms of the partition table 40, by the output torque.

The ratio of driven worms to worm gears is 72: 1. Thus, when the worm rotates 72, the partition table 40 rotates 360 °. Therefore, when the worm rotates once, the angle of the partition table 40 is divided by 5 degrees, and the partition table 40 is rotated.

As described above, the present invention can rotate the partitioning table by using a vector control technique and a low-cost three-phase induction motor instead of a conventional expensive servo motor, thereby localizing the partitioning table at a low cost, and also providing high output at low speed. There is an effect that can be obtained.

Claims (1)

CLAIMS 1. A partition table of a vertical universal milling machine for processing a workpiece placed thereon by rotation of a split table, the partition table comprising: an AC / DC converter (11) for converting a three-phase AC power source into a single-phase DC power source; A microprocessor 14 to which the converted single-phase DC power is applied and which has a vector control program to control the rotational speed and output torque of the three-phase induction motor 30; A DC / AC converter 13 for converting single-phase DC power output from the AC / DC converter 11 into three-phase AC power; A control device comprising a power amplifier (12) for amplifying the signal to control the DC / AC converter with the microprocessor control signal; A three-phase induction motor (30) for rotating the partition table (40) per revolution of the worm by the vector control signal of the microprocessor (14); The encoder 20 is configured to correct the number of rotations of the three-phase induction motor 30 and to output the correction value to the microprocessor 14 to adjust the split angle and position of the split table 40. Split table drive device of vertical universal milling machine.