JPH0671527A - Screw tightening robot for industrial use and its screw tightening method - Google Patents

Abstract

PURPOSE:To increase the service life of a screw tightening bit and to reduce damages to a work in a screw tightening robot for industrial use where the pattern control is executed. CONSTITUTION:A screw tightening robot is provided with a tightening motor 4, a bit 2 which is directly connected to the motor 4, and a controller 5 to execute the pattern control of the work amount and the acting time of the motor 4, and the fifth process is added after the screw or the nut is tightened, and the bit 2 is reversely rotated by controlling the reverse rotation of the motor 4 by the controller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial screw tightening robot for pattern control and a screw tightening method therefor.

[0002]

2. Description of the Related Art In recent years, screw tightening robots that perform pattern control have been widely used for industrial purposes in order to efficiently tighten screws or nuts with high torque.

A conventional screw tightening method is disclosed in Japanese Patent Laid-Open No. 63-2.
As shown in Japanese Patent No. 37827, there is a method of rotating a bit in a reverse direction after completion of screw tightening using a clutch device.
No industrial screw tightening robot with pattern control reverses the bit.

The conventional screw tightening operation will be described below with reference to FIG. FIG. 3 is a process diagram from the start of screw tightening to the completion of screw tightening in the screw tightening operation process. FIG. 3 shows that the screw or nut is screwed by the bit 2 in a pattern determined by the work 6 provided at a predetermined position. The process is shown. The tip of the bit 2 is engaged with the head of the screw or nut, and the bit 2 is moved at the first speed to a position where the tip of the screw or nut reaches the work 6 and starts screw tightening. The bit 2 is forcibly moved at the second speed corresponding to the advancement of the screw or nut accompanying the rotation of the bit 2 until the first step and the tightening of the screw or nut to the work 6 after the first step are completed. Second
Step, the third step of detecting the seating of the screw or nut on the surface of the workpiece 6, and the rotation speed of the bit 2 is controlled after the third step, and the current value flowing through the tightening motor 4 is gradually increased to increase the screw tightening torque. There is a fourth step in which the screw is gradually increased, and when the torque reaches a predetermined torque, the torque is maintained for a predetermined time to determine a screw fool.

[0005]

However, as shown in FIG. 4, when the screws or nuts are tightened with a high torque, at the end of the tightening in the fourth step, the hexagons of the screw crosses or the nuts are provided with the bit 2 for tightening the screws. There are problems that the tip bites more frequently, the wear of the screw fastening bit 2 is shortened, and the work 6 is damaged.

The present invention solves the above problems, and an object of the present invention is to extend the service life of a screw fastening bit and reduce damage to a work.

[0007]

In order to achieve the above object, the present invention comprises a tightening motor, a bit directly connected to the motor, and a controller for pattern-controlling the work and operating time of the motor. After the tightening of the screw or nut is completed, the controller reversely rotates the motor to reversely rotate the bit.

[0008]

According to the present invention, in the above-mentioned structure, by adding the fifth step of rotating the bit in the reverse direction after the tightening of the screw or the nut, the bit does not bite even when tightened with a high torque.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, an industrial screw tightening robot is configured by attaching a screw tightening bit 2 and a screw suction vacuum pipe 3 to a screw tightening head 1. The bit 2 is controlled by a controller 5. It is adapted to be rotationally driven by a pattern-controlled motor 4.

The above construction is the same as that of the conventional example. However, the difference from the conventional example is that, as shown in FIG. 2, in a screw tightening robot that performs pattern control for tightening a screw or a nut with high torque, after tightening, After the first to fourth steps of the screw tightening operation step described in FIG. 3, a fifth step is further added to control the motor 4 in the reverse rotation by the controller 5 and rotate the bit 2 in the reverse direction. Is.

As described above, according to this embodiment, by rotating the bit 2 in the reverse direction, it is possible to prevent the tip of the bit 2 from sticking to the screw or the nut.

[0012]

As is apparent from the above description, according to the present invention, in an industrial screw tightening robot for pattern control, after tightening a screw or a nut, the first to fourth conventional processes are performed. By adding the fifth step of rotating the bit in the reverse direction, bite of the bit and the screw or nut can be prevented from being bitten, and the life of the bit and the damage to the work can be reduced.

[Brief description of drawings]

FIG. 1 is a side sectional view of an essential part of an industrial screw tightening robot of the present invention.

FIG. 2 is a process diagram showing a screw tightening operation of the screw tightening robot of the present invention.

FIG. 3 is a process diagram showing a screw tightening operation of a conventional example.

FIG. 4 is a diagram showing a relationship between tightening torque and biting frequency.

[Explanation of symbols] 1 head 2 bits 4 motor 5 controller

Claims (2)

[Claims] 1. A screw tightening robot having X, Y, Z axes and a screw tightening head and performing pattern control for tightening a screw or a nut with high torque, a tightening motor, a bit directly connected to the motor, and a motor. An industrial screw tightening robot, comprising: a controller for controlling a work amount and an operating time of the device, and reversely controlling a motor by the controller to reversely rotate a bit after tightening a screw or a nut. 2. A tightening motor, a bit directly connected to the motor, and a controller for pattern-controlling the work and operating time of the motor. After the screw or nut is tightened, the controller reversely rotates the motor. A screw tightening method for an industrial screw tightening robot characterized by controlling and rotating a bit in a reverse direction.