JPH04310314A - Synchronous tap device - Google Patents

Abstract

PURPOSE:To obtain a synchronous tap device eliminating a synchronous slippage at a normal and reverse rotation switching time by having a backrush correction on the motion of a cutting shaft in a synchronous tap device executing the synchronous control of the cutting shaft and a feed shaft. CONSTITUTION:A speed command is given to a speed control part 4 through a changeover switch 6 at the speed loop time to drive a motor 1. The changeover switch 5 is then switched to the lower side in order to come in a synchronous tap, the output of a position control part 5 is inputted to the speed control part 4 and a position loop is integrated. Thereafter, the position command is given to the position control part 5, the speed command is inputted to the speed control part 4 with the speed command being calculated from the difference in the value of after passing the positional feedback from a position detector 3 through a backrush correcter 7 and a motor 1 is driven. The synchronous slippage at the normal and reverse rotation switching time can be eliminated because of the backrush of a machine being corrected like this and a highly accurate synchronous tap can be executed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous tap device for an electric motor that drives a rotating shaft.

0002

2. Description of the Related Art FIG. 4 is a block diagram showing a conventional synchronous tap function. In the figure, 1 is an electric motor, 2 is a speed detector attached to the electric motor 1, and 3 is a rotating shaft driven by the electric motor 1. 4 is a speed control unit that controls the electric motor 1; 5 is a position control unit that generates a command for the speed control unit 4 from the position command and position feedback; 6
is a changeover switch between a speed command and a command from the speed control section 4.

Next, the operation will be explained. During the speed loop, a speed command is given to the speed control section 4 through the changeover switch 7 to drive the electric motor 1. Next, in order to enter cutting axis-feed axis synchronous control, the changeover switch 6 is switched to the lower side, and the output of the position control section 5 is input to the speed control section 4, forming a position loop. Thereafter, the position command is given to the position control section 5, a speed command is calculated from the difference with the position feedback fed back from the position detector 3, and is input to the speed control section 4 to drive the electric motor 1.

[0004] Other reference technical documents related to this invention include JP-A-57-139820 and JP-A-60-
Some of these are disclosed in JP-A No. 172444 and JP-A-2-15311.

[0005]

[Problems to be Solved by the Invention] Since the conventional synchronous tap device is configured as described above, backlash between the motor and the position detector is not taken into account, so the amount of position feedback when switching between forward and reverse directions is reduced. There were problems such as inaccurate movement and synchronization with the feed axis on which backlash correction was being performed.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a synchronous tap device that can eliminate synchronization deviation when switching between forward and reverse directions.

[0007]

[Means for Solving the Problems] Tap cutting of a machine tool according to the present invention is carried out by a floating tap chuck and the cutting axis is
In a synchronous tap device that performs feed axis synchronous control (synchronous tap), backlash correction is provided for the operation of the cutting axis.

[0008]

[Operation] The synchronous tap device according to the present invention is designed to prevent a temporary decrease in the feedback amount caused by backlash during forward/reverse switching by adding the backlash amount to the feedback amount. As a result, the cutting axis can be controlled so as to be stabilized by backlash correction and correctly synchronized with the feed axis.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is an electric motor, 2 is a speed detector attached to the electric motor 1, 3 is a position detector attached to a rotating shaft driven by the electric motor 1, 4 is a speed controller that controls the electric motor 1, and 5 is a speed detector attached to the electric motor 1. is a position control unit that generates a command to the speed control unit 4 from the position command and position feedback; 6 is a changeover switch between the speed command and the command from the speed control unit 4; and 7 is a position feedback value when the sign of the position command changes. This is a backlash corrector that performs backlash correction.

Next, the operation will be explained. During the speed loop, a speed command is given to the speed control section 4 through the changeover switch 6, and drives the electric motor 1. Then, in order to enter the synchronization tap, the changeover switch 6 is switched to the lower side, the output of the position control section 5 is inputted to the speed control section 4, and a position loop is installed. Thereafter, the position command is given to the position control section 5, and the speed command is calculated from the difference between the position feedback from the position detector 3 and the value after passing through the backlash corrector 7, and is input to the speed control section 4. and drives the electric motor 1.

This backlash operation will be explained using the flowchart shown in FIG. 2. First, it is determined whether or not a position loop is in progress (S10). When entering the sync tap,
Because of the speed loop, speed → position loop switching operation (S11
), and at the same time, the direction in which the backlash is generated is set by the switching operation (S12).

Next, if it is determined in step 10 that the position loop is in progress, the command direction and backlash direction are compared (S13), and it is determined whether correction is required (S14). When the two are reversed, the backlash direction is updated to indicate that correction has been made (S15), and the backlash amount is stored in the correction value x (S16). Otherwise, the correction value x is set to 0 (S17).

Thereafter, the feedback amount and the correction value x are added (S18), the corrected feedback amount is input to the position loop control (S19), and a speed command is calculated.

In the above embodiment, the backlash corrector 7 is used to correct position feedback, but it may also be used to correct position commands as shown in FIG.

[0015]

As described above, according to the present invention, the backlash of the machine can be corrected, so that synchronization deviation during forward/reverse switching can be eliminated, and highly accurate synchronous tapping can be performed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a synchronous tap device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the synchronous tap device shown in FIG. 1;

FIG. 3 is a block diagram showing a schematic configuration of a synchronous tap device according to another embodiment of the present invention.

FIG. 4 is a block diagram showing a schematic configuration of a conventional synchronous tap device.

[Explanation of symbols]

1 Electric motor 2 Speed detector 3 Position detector 4 Speed control section 5 Position control section 6 Selector switch 7 Backlash corrector

Claims (1)

[Claims] 1. In a synchronous tapping device that performs cutting axis-feed axis synchronous control (synchronous tapping) by floating tap chuck for tap cutting of a machine tool, backlash compensation is provided for the operation of the cutting axis. Features a synchronous tap device.