JP2684673B2 - Screw adjuster - Google Patents

Description

The present invention relates to a magnetic head of a video tape recorder (hereinafter referred to as a VTR) or the like.
The present invention relates to a screw adjusting device that adjusts a position with high accuracy.

2. Description of the Related Art Conventionally, tilt adjustment using a screw mechanism has been performed with a delicate sense of human, and there is an increasing demand for a screw adjusting device that is automated at high speed and with high accuracy.

A conventional example of automatic position adjustment by tilting the head fastened on the cylinder of the VTR will be described below.

FIG. 3 is a cross-sectional view of a main part of a head adjusting unit that fastens the head of the VTR cylinder and adjusts the tilt. In FIG. 2, 1 is a rotary cylinder, 2 is a head base fastened to the rotary cylinder 1, 3 is a head chip on the head base 2, 4 is a screw fastening the head base 2 to the rotary cylinder 1, and 5 is a screw. It is a screw that pushes down the head base 2 to make a tilt.

In the head adjusting unit 20 configured as described above, the position of the head chip 3 in the rotation axis direction of the rotary cylinder 1 is detected by visual recognition, and if there is a difference from a predetermined position, the screw 5 is driven by an electric motor (not shown). ) Etc. to issue a command to rotate and adjust the position. Before the adjustment, it is necessary to stop the tip of the screw 5 in contact with the head base 2 without moving the position of the head base 2. Therefore, the screw 5 is rotated by a constant amount and the position where the head chip 3 starts to move is detected by visual recognition.

However, in the method as described above, since the adjustment amount is minute, the amount of motor rotation per time is also minute, and since the insertion length of the screw 5 is long, the movement of the head chip cannot be started. Since a large number of motor steps are required until detection, and the processing by visual recognition cannot reduce the time per step to a certain value or less, as a result, until the screw 5 comes into contact with the head base 2 and stops. It had a problem that it took a very long time.

In view of the above problems, the present invention provides a high-speed, high-accuracy screw adjusting device with visual recognition, which includes a control circuit for bringing a tip of a screw into contact with a head base with high speed and high precision.

Means for Solving the Problems In order to solve the above-mentioned problems, a screw adjusting device of the present invention includes an electric motor that rotationally drives a screw, a driving unit that drives the electric motor, and a speed control unit that gives a torque instruction to the driving unit. A motor rotation detection means, a positioning control means for inputting the detection signal and outputting a speed command to a designated position, a control means for giving a predetermined torque limit, a motor torque detection means, and a torque limit Comparing means for comparing the detected value with the detected torque value, control means for stopping and controlling the electric motor with a signal from the comparison, an image pickup section for picking up an image of an object whose position is to be adjusted, and a video signal from the image pickup section for processing the object. The configuration includes a visual recognition unit that measures the position of an object, and a control unit that gives a command to the positioning control unit so that the object is located at a predetermined position based on information from the visual recognition unit. .

Effect The present invention, by the above-described configuration, rotates the electric motor at a high speed at a constant speed until the screw comes into contact with the head base, detects that the screw comes into contact with the head base and the load torque increases, and stops the electric motor. After that, the position is controlled based on the position information of the head chip by visual recognition.

Example A screw adjusting device according to an example of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a screw adjusting device according to an embodiment of the present invention. In FIG. 1, 6 is a main body, 7 is a head base fastened to the main body 6, 8 is a head chip on the head base 7, 9 is a screw fastening the head base 7 to the main body 6, and 10 is the head base 7. Screw that pushes down and makes tilt, 11 is a bit inserted in screw 10 and transmitting rotation to it, 12 is an electric motor that rotates screw 10 through bit 11, 13 is a rotation detector that detects the rotation state of electric motor 12, 14
Is a rotation speed detector for detecting the rotation speed of the electric motor 12, 15 is positioning control means for accumulating signals and command signals of the rotation detector 13, and 16 is an electric motor according to an instruction from the positioning control means 15.
Speed control means for controlling the speed of 12; 17 is speed control means 16
Motor drive means for driving the electric motor 12 in accordance with the instruction, 18 is a torque detection means of the motor, 19 is a torque control means for giving a predetermined torque limit, 20 is a comparison means for comparing the torque limit value with the detected torque, and 21 is a head chip. Image capturing unit for capturing 8
Is a visual recognition unit that processes the video signal from the image pickup unit 21 and measures the position of the head chip 8, and 23 gives a rotation command to the positioning control unit 15, and detects the detection signal of the comparison unit 20 and the visual recognition unit.
Command control means for inputting the detection result of 22 and controlling the electric motor 12.

The operation of the screw adjusting device configured as described above will be described below with reference to FIGS. 1 and 3.

First, the command control means 23 issues a command to rotate at a constant speed at high speed. Immediately after the electric motor 12 starts rotating according to the command, the command control means 23 also sets the torque limit, and operates the electric motor drive means 17 so that the electric motor 12 does not output a torque above a certain level.

Then, the torque of the electric motor 12 is detected, and when the comparison means 20 detects that the torque exceeds a certain constant value, the electric motor 12
To stop immediately. Next, the torque limitation is released, and the visual recognition unit 22 measures the position of the head chip 8. If the head chip 8 is not at the predetermined position, the electric motor 12 is rotated by a certain pulse and the electric motor 12 is controlled to come to the predetermined position.

 The above operation flow is shown in FIG.

By performing the torque limitation and detection as described above and switching from the speed control to the position control, it is possible to perform high-speed and high-accuracy position adjustment with the screw.

EFFECTS OF THE INVENTION The present invention is provided with a torque detecting means for an electric motor and a comparing means for comparing the torque detected by the torque detecting means with a reference value of the torque, and stops the electric motor when the torque exceeds the reference value. Then, by switching from the speed control until then to the positioning control based on the information from the recognition device, it is possible to perform high-accuracy positioning at a high speed by tilting the screw.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a screw adjusting device according to an embodiment of the present invention, FIG. 2 is a sectional view of an essential part of a head adjusting portion, and FIG. 3 is an operation of the screw adjusting device according to an embodiment of the present invention. It is a flowchart. 6 …… Main body, 7 …… Head base (target member), 10 ……
Screw, 12 ... Electric motor, 13 ... Rotation detector (rotation detection means), 15 ... Positioning control means, 16 ... Speed control means,
17 ... motor driving means, 18 ... motor torque detecting means,
19 ... Torque control means, 20 ... Comparison means, 21 ... Imaging section, 22 ... Visual recognition section, 23 ... Command control means.

Claims (1)

(57) [Claims] 1. A screw screwed with a main body, a target member attached to the main body, the position of which is adjusted by abutting the screw, an electric motor for rotationally driving the screw, and a drive unit for driving the electric motor. A speed control means for giving a torque instruction to the drive means, a rotation detection means attached to the electric motor, and a positioning control means for inputting a signal from the rotation detection means and outputting a speed command to a designated position,
A torque control unit that gives a predetermined torque limit, a torque detection unit of the electric motor, a comparison unit that compares the torque limit value and the torque detection value, and a command to stop and control the electric motor with a signal from the comparison unit. The control unit, an imaging unit that images the target member, and a visual recognition unit that processes a video signal from the imaging unit and measures the position of the target member, and the electric motor is stopped by the command control unit. After that, the position information of the target member is input from the visual recognition unit, and the command control unit is configured to give a command to the positioning control unit so that the position becomes a predetermined position. .