JPH03117514A - Control unit for simultaneous tapping - Google Patents

Abstract

PURPOSE:To enable a simultaneous tapping in the shortest time, by calculating the optimum time constant from the parameter value set with the torque function of a main shaft and the load inertia of the main shaft and a designated number of the main shaft rotation, and performing an adjustable speed control based on the time constant. CONSTITUTION:In a constant arithmetic circuit 4, the main shaft rotation number 3 obtained from a control part 14 is fetched and on the other hand a torque is calculated from the main shaft characteristics 1 set as the function of the main shaft speed by a parameter inside a control unit. The minimum time constant 5 is calculated from the calculated torque and the load inertia 2 of the main shaft set by the parameter. The torque added with the main shaft rotation number is thus obtained, so the time constant equivalent to the rotation number thereof is obtained and an adjustable speed control is performed at an adjustable speed circuit 6 based on this time constant.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is a synchronized tap with 81 fewer NC operations! Regarding IJ control device.

<Prior Art> FIG. 2 shows a block diagram of a synchronous tap control 9. When a synchronous tap command is converted into a feed amount by a control unit 9, a pulse distributor 10 converts the synchronous tap command into a feed amount corresponding to this feed amount. Changed to pulse amount. Next, the acceleration/deceleration circuit 8 performs acceleration/deceleration control with a constant time constant 7 given by a parameter, and synchronous tap control is performed by giving commands to the spindle control circuit 11 and the feed control circuit 12.

<Problems to be Solved by the Invention> In the above-mentioned synchronous tap control, the time constant 7 is adjusted to the state with the largest time constant, and is adjusted to the worst condition determined by the torque at the maximum spindle rotation and the load inertia of the spindle. ing.

However, operation at a rotation speed of 1, which is lower than the maximum spindle rotation, is frequently performed, and even though acceleration/deceleration control is possible with a short time constant for the spindle, this control does not meet the worst condition set as a parameter. The problem is that acceleration/deceleration operation is performed with a large time constant, resulting in a long machining time.

An object of the present invention is to provide a synchronous tap control device that reduces machining time.

<Means for Solving the Problem> The present invention achieves the above-mentioned object, and the present invention provides a machine tool with a set parameter consisting of a torque function of the spindle and a load inertia of the spindle in an NC control device or a synchronous tap control device of a machine tool. From the value and the commanded spindle rotation speed! The present invention is characterized in that it includes a time constant calculation circuit that calculates a time constant of &appropriate, and an acceleration/deceleration control circuit that performs acceleration/deceleration control based on the time constant of the time constant calculation circuit.

Function> The time constant calculation circuit calculates the torque from the torque characteristic formula and the command rotation speed, calculates the time constant of the main shaft from this torque and load inertia, and performs acceleration/deceleration control using this time constant.

Embodiments The present invention will now be described in detail with reference to FIGS. 1 and 3. In FIG. 1, 13 is a command tape for giving a synchronous tap command, 14 is a control unit that converts the command into a feed amount, 15 is a pulse distributor that obtains the amount of feed pulses, and 6 is an addition at a given time constant. An acceleration/deceleration control circuit performs deceleration control, 16 is a main shaft control circuit, and 17 is a feed control circuit.

When giving a time constant to the acceleration/deceleration control circuit 6, the time constant calculation circuit 4 is used. In this time constant calculation circuit 4, the control section 1
The spindle rotation speed 3 obtained from 4 is taken in, and the torque is calculated from the spindle torque characteristic formula 1 shown in Fig. 3, which is set as a function of spindle speed using parameters in the control device, and is set using this torque and parameters. Load inertia 2 of the spindle
The minimum time constant 5 is calculated from .

For example, the spindle torque characteristic formula 1 shows that the spindle rotation speed S is O<S≦
In the case of S, the torque increases by one revolution S, and SL<S≦82
In the case of torque, /S.

Furthermore, when the rotational speed S increases and S2<S≦83, the torque is set to /S.

In this way, by taking the spindle rotation speed into consideration and obtaining the torque, it is possible to obtain a time constant that corresponds to the rotation speed. As a result, machining without wasted time is realized when performing synchronous tap acceleration/deceleration control.

<Effects of the Invention> As explained below, in the present invention, the synchronous tapping operation is performed using the shortest time constant that can be controlled at the commanded spindle rotation speed, instead of the time constant at the maximum spindle rotation as in the conventional case. Therefore, even when the rotation speed differs, synchronous tapping can be performed in the shortest possible time.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a block diagram of a conventional example, and FIG. 3 is an explanatory diagram of an example of a spindle torque characteristic equation. In the figure, 1 is the parameter of the spindle torque characteristic equation, 2 is the load inertia, 3 is the spindle rotation speed, 4 is the time constant calculation circuit, 5 is the time constant, and 6 is the acceleration/deceleration control circuit. Patent applicant Mitsubishi Heavy Industries, Ltd. Agent

Claims (1)

[Claims] In a synchronous tap control device in an NC control device of a machine tool, an optimal time constant is calculated from a set parameter value consisting of a spindle torque function and a spindle load inertia and a commanded spindle rotation speed. What is claimed is: 1. A synchronous tap control device comprising: a time constant calculation circuit that performs acceleration/deceleration control using a time constant of the time constant calculation circuit;