JPH02237743A - Main spindle control system of numerical controller - Google Patents

Abstract

PURPOSE:To enable the control synchronized with a feed shaft without providing a detector on the side of a main spindle by inputting a speed detection valve and a one-rotation signal pulse of a position coder of a spindle motor and constituting the device in the title to create a one-rotation signal of a main spindle on the basis of the gear ratio of their pulse and a transmission. CONSTITUTION:A position coder 16 provided on a spindle motor 23 outputs a speed detection pulse and a one-rotation signal pulse of the spindle motor 23. At this time, as the spindle motor 23 and a main spindle 27 are connected to each other at a fixed gear ratio, the same speed detection pulse and one- rotation signal pulse as the position coder 16 provided on the main spindle 27 are obtained by calculating the speed detection pulse and the one-rotation signal pulse on the basis of this gear ratio. Consequently, it is not necessary to provide the position coder 16 formerly provided on the side of the main spindle 27 and it is possible to perform thread chasing with one hundred and sixty one pieces of position coders provided on the spindle motor 23.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a main shaft control method for a numerical control device, and particularly to a method for controlling a main shaft of a numerical control device that synchronizes and controls a main shaft rotating through a transmission and a feed shaft. Regarding spindle control method.

[Conventional technology]

Conventionally, when thread cutting was performed using an NC lathe, this was achieved by generating a signal for one revolution of the main spindle using a position coder installed on the main spindle, inputting this to the NC device, and synchronizing the feed axis with the main spindle.

This conventional technique will be explained below with reference to the drawings.

FIG. 2 is a diagram showing a spindle control system of a numerical control device when performing conventional thread cutting. In the figure, numerical control device 2
1 controls the entire machine tool. The numerical control device 21 outputs a rotation speed command signal for the spindle motor 23 to the spindle amplifier 22 . The spindle amplifier 22 outputs a current according to the rotational speed command signal to the spindle motor 23, causing the spindle motor 23 to rotate. A tacho generator 24 is attached to the spindle motor 23 to generate a voltage signal according to its rotation speed. The voltage signal of the tacho generator 24 is fed back to the spindle amplifier 22 as a speed feedback signal.

The main shaft 27 is connected to the output shaft of a spindle motor 23 via a transmission (gear) 25. Therefore, the main shaft 27 rotates at a rotational speed corresponding to the gear ratio of the transmission 25. A position coder 26 for detecting the position of the main shaft 27 is connected to the main shaft 27. A one-rotation signal pulse and a speed detection pulse are taken into the numerical control device 21 from the position coder 26 .

The numerical control device 21 outputs a feed speed command signal for the servo motor 33 for driving the feed shaft to the servo amplifier 3l. The servo amplifier 31 drives the servo motor 33 according to this feed speed command signal.

The servo motor 33 has a built-in pulse coder 32 and is used as a position detector. This pulse coder 3
2 is also used as a speed detector to generate a speed signal. In addition, a linear scale may be used as a position detector for a servo motor. Servo motor 3
3 rotates the ball screw 30 to move the bar 29.

The cutting tool 2 is
Thread cutting is performed by moving 9.

[Problems to be Solved by the Invention] In the above-mentioned conventional technology, the spindle motor 23 and the main shaft 27
The main shaft 27 is connected to the main shaft 27 via the transmission 25.
A position coder 26 is provided at the position coder 26, and the one-rotation signal pulse and speed detection pulse from the position coder 26 are inputted to a numerical control device to detect the rotation angle and speed of the main shaft 27. However, since the position coder is provided on the spindle side, there is a problem in that the structure of the spindle peripheral equipment becomes complicated.

The present invention has been made in view of these points, and is a numerical control system that can detect the rotational speed of the spindle and perform control in synchronization with the feed axis without providing a detection device such as a position coder on the spindle side. The purpose is to provide a spindle control method for equipment.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides a main shaft control method of a numerical control device that controls the rotation of a main shaft connected to a spindle motor via a transmission. and a main shaft control circuit that receives a speed detection pulse and one rotation signal pulse of a coder and generates a one rotation signal of the main shaft based on the speed detection pulse, the one rotation signal pulse, and the gear ratio of the transmission. A spindle control method for a numerical control device is provided.

[Effect]

A position coder provided in the spindle motor outputs a spindle motor speed detection pulse and a one-rotation signal pulse. At this time, since the spindle motor and the main shaft are connected by a transmission at a constant gear ratio, by calculating the speed detection pulse and one revolution signal pulse based on this gear ratio, it is as if a position coder is attached to the main shaft. It is possible to obtain the same one-rotation signal pulse and speed detection pulse as provided. Therefore, it is no longer necessary to provide the conventional position coder on the spindle, and thread cutting can be performed with a single position coder provided on the spindle motor.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram of a second spindle control method of a numerical control device according to an embodiment of the present invention. In this figure, only the parts necessary for explaining the embodiment are shown, and the internal configuration of the numerical control device 1 is omitted. Components that are the same as those in FIG. 2 are given the same reference numerals, so their explanation will be omitted.

In this embodiment, the position coder for detecting the rotation angle (position) and speed of the main shaft 270 is removed, and the position coder 16 is provided in place of the tachogenerator of the spindle motor 23. The position coder 16 feed-hacks the one-rotation signal pulse of the spindle motor 23 and the speed detection pulse to the main shaft control circuit 10 of the numerical control device 1. Furthermore, the speed detection pulse is also feedhacked to the spindle amplifier 22 as a speed feedback pulse. This speed Jjl output pulse is F/V in the spindle amplifier 22.
It is converted and used as a speed signal.

The NC bus 18 is used for various data transmission between components (not shown) in the numerical control device 1 (microprocessor, RAM, ROM, nonvolatile memory, operation panel, display device, etc.).

The main shaft control circuit 10 controls the position and speed of the main shaft 27 connected to the spindle motor 23. The microprocessor 11 controls the entire spindle control circuit IO.

The memory 12 consists of a ROM that stores control programs and a RAM that stores data, and is used for data transmission between each component in the numerical control device 1 via the NC bus 18.

The counter 13 takes in the one-rotation signal pulse and speed detection pulse of the position coder 16, and counts the number of each pulse independently. The D/A converter 14 converts the digital speed command into an analog output and outputs it to the spindle amplifier 22. The register 15 is the gear ratio P of the transmission 25.
=M/N (M is the number of teeth of the main shaft 27, N is the number of teeth of the spindle motor 23) is stored.

The axis control circuit 17 connects the servo motor 3 via the NC bus 18.
3, and outputs a feed speed command signal to the servo amplifier 31.

The counter 13 counts one rotation signal pulse and speed detection pulse of the position coder 16.

The microprocessor 11 calculates the number NN of speed detection pulses outputted during one rotation signal pulse of the position coder 16 from the value of the counter 13, and stores it in the memory 12.

The microprocessor 11 then stores in the memory 12 a value NP obtained by multiplying the gear ratio P stored in the register 15 by the number NN of speed detection pulses output during one rotation signal pulse.
The speed detection pulse value is counted and assigned, and a one-rotation signal is generated every count number NP.

That is, the number of teeth M of the main shaft 27 is 30, and the spindle motor 23
When the number of teeth N is 20, the gear ratio P is 3/2.

Therefore, if the number NN of speed detection pulses output during one rotation signal pulse of the spindle motor 23 is iioo,i, the value NP multiplied by the gear ratio 3/2 is "15".
o”. Therefore, the number of speed detection pulses of the spindle motor 23 is counted up, and the count is 1/number N.
If one rotation signal is generated every Pfl50j, the main shaft 2
A one-rotation signal corresponding to one rotation of 7 is generated. At this time,
After setting the value NP in the memory 12, the speed detection pulse counter 13 may be reset every count l/number NP to generate one revolution signal.

Furthermore, when the gear ratio P is expressed as a fraction, the value of the numerator is calculated, the value of the one-rotation signal pulse is counted and amplified, and when the count reaches the value of the numerator, the one-rotation signal is generated. good. That is, when the number M of teeth of the main shaft 27 is 30 and the number N of teeth of the spindle motor 23 is 20, the fractional value of the gear ratio P is 3/2. Therefore, if the spindle motor 23's one-rotation signal pulse value reaches the numerator value 3, the spindle's one-rotation signal will be generated, and the one-rotation signal will be generated in synchronization with the two rotations of the spindle motor 27. . In this case, when the value of the numerator is small, synchronization with the one-rotation signal can be achieved in a short period, but when the value of the numerator is large, the period becomes long and there is a problem that it takes a long time to achieve synchronization.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a spindle control system of a numerical control device according to an embodiment of the present invention, and FIG. 2 is a diagram showing a spindle control system of a numerical control device when performing conventional thread cutting. 1-・1-----1-----1 numerical control device 10...
−・−・=・・−・−・Spindle control circuit 1.3−−1−−
・・１－－－１－・・・Counter 1 ５－－－・－・－・
−Register 16・1・−・−・・・・1・・・・Position coder 2 3−−−−−−−−−−−Spindle motor 25・
---11-・----- The rotational speed of the feed shaft can be grasped by the numerical control device, which has the effect of allowing control to be performed in synchronization with the feed axis. Patent applicant: Agent for FANUC Co., Ltd. Patent attorney: Takeshi Hattori

Claims (3)

[Claims] (1) In a spindle control method of a numerical control device that controls the rotation of a spindle connected to a spindle motor via a transmission, the spindle motor includes a position coder provided on the spindle motor, a speed detection pulse of the position coder, and one rotation. and a main shaft control circuit that inputs signal pulses and generates one revolution signal of the main shaft based on the speed detection pulse, the one revolution signal pulse, and the gear ratio of the transmission. Spindle control method. (2) The main shaft control circuit includes a counter that counts each speed detection pulse and one revolution signal pulse of the position coder, and a gear ratio P=M/N of the transmission (M is the number of teeth of the main shaft,
N is a register for storing the number of teeth of the spindle motor; and counting the speed detection pulses until a value obtained by multiplying the number of speed detection pulses during one rotation signal pulse by the gear ratio is reached. 2. The spindle control method for a numerical control device according to claim 1, wherein a one-rotation signal of the spindle is generated by: (3) The main shaft control circuit has a gear ratio P=M/of the transmission.
N (M is the number of teeth of the spindle motor, N is the number of teeth of the spindle motor), and a counter that counts the one rotation signal pulse, and the numerator when the gear ratio is expressed as a fraction. 2. The spindle control method for a numerical control device according to claim 1, wherein the one-rotation signal of the spindle is generated by counting the one-rotation signal pulses until a value of .