JP2658160B2 - Magnetic head mounting device - Google Patents

Description

The present invention relates to a magnetic head mounting device for mounting a magnetic head used for a VTR, an RDAT, etc., and particularly to a magnetic head mounted at a predetermined position on a rotating drum. The present invention relates to a mounting device adapted to be mounted.

[Summary of the Invention]

The present invention relates to an apparatus for mounting a magnetic head of a VTR or RDAT on a rotating drum, wherein a center position of the rotating drum is obtained from circumferential runout information obtained by rotating the rotating drum once, and a mounting position of the magnetic head is determined. The magnetic head is mounted on the rotating drum by positioning with reference to the above center position by the correcting means for correcting, and the magnetic head is mounted on the rotating drum with high accuracy and efficiently. is there.

[Conventional technology]

In general, in VTRs and RDATs, a magnetic head is mounted on a rotating drum, a magnetic tape is helically wound around the drum, and the magnetic head is rotated together with the rotating drum to form an oblique track on the magnetic tape. Thus, recording and reproduction of the helical scan method are performed.

In such an apparatus, it is necessary to correctly mount the magnetic head at a predetermined position on the rotating drum. Especially VT
The number of magnetic heads that can be mounted on a rotating drum has increased due to the increasing functionality and variety of models of R and RDAT. There is a tendency to provide multiple microscopes. In such an apparatus, a method in which a magnetic head is mounted while observing with a microscope while rotating a drum has been adopted.

In the case of high-precision mounting, a method has conventionally been adopted in which the center of the rotary head drum is aligned with the optical axis of the microscope. In this method, the drum is set on a base such that circumferential runout is minimized while rotating the head drum. This means that the rotation center of the base and the rotation center of the drum coincide with each other. The position of the magnetic head is adjusted while confirming the position of the magnetic head with a microscope whose optical axis coincides with the center of rotation of the base in advance. In this state, the magnetic head is mounted and fixed on the rotating drum. I was

[Problems to be solved by the invention]

According to such a conventional magnetic head mounting device,
It has two drawbacks: low accuracy of angle division and poor workability. The first disadvantage is that it leads to a mounting error of the magnetic head. That is, even if the rotary drum is set so as to minimize the circumferential runout, the center of the rotary drum does not surely coincide with the center of the base. In actual use on a production line, there is a limit in accuracy, and the distance between the two rotation centers is at most 2
It will be within about μm. Then, in the case of such an accuracy, the angle split alone is 2 μm. Such an error leads to an error in the mounting position of the magnetic head. The second disadvantage is that it takes about 5 minutes for each drum set to minimize the runout. Therefore, in order to mass-produce the head drum, many mounting devices are required, and the working efficiency is extremely low.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a magnetic head mounting device that can accurately and efficiently mount a magnetic head on a rotating drum. Things.

[Means for solving the problem]

The present invention mounts a rotating drum on a base,
Detecting means for detecting a center position of the rotary drum with respect to a center of the base, wherein the magnetic head is mounted at a predetermined position on the rotary drum while rotating the rotary drum by a predetermined angle by the base; Correction means for correcting the mounting position of the magnetic head according to the center position of the rotary drum.

[Operation] Therefore, according to the present invention, the position of the center of the rotary drum with respect to the center of the base is detected by the detecting means, and the magnetic head is mounted in a state corrected by the correcting means in accordance with this detection. Is possible,
It is possible to provide a head mounting device that can perform high-precision angle splitting with good workability, and it has increased versatility.Even if a new drum is introduced, it can be easily modified by changing the tooling, and the equipment becomes obsolete. Can be prevented.

〔Example〕

FIG. 1 shows the entire structure of a magnetic head mounting apparatus according to one embodiment of the present invention, and this apparatus comprises a gantry.
A support plate 12 is supported on a mount 10 via a spring 11 in a vibration-proof manner. The support plate 12 further includes a bearing 13, and the rotating main shaft 14 is rotatably supported by the bearing 13. The lower end of the rotating main shaft 14 is connected to a disk 16 via a coupling 15. Then, for example, white and black stripes are formed on the outer peripheral surface of the disk 16, and the rotation angle is detected by detecting the stripes by the encoder 17. The encoder 17 is further connected to a motor 19 via a coupling 18. The motor 19 is supported by the support plate 12 by a pair of arms 20. The rotating main shaft 14 has a brake disk 21, and the disk 21 is used to stop the main shaft 14 accurately at a predetermined rotational position.

A base 23 is mounted on the rotating spindle 14, and this base
A rotary drum 24 is placed on the top 23. Note that the rotary drum 24 is pressed onto the base 23 by the holding metal fitting 25. The magnetic head 26 is mounted and fixed to the rotating drum 24 by this device. The displacement of the center of the rotary drum 24 with respect to the center of the base 23 is detected by a circumferential runout detector 27, and the output of the detector 27 is supplied to a control unit 28.

The magnetic head 26 is held by a chuck 29. The chuck 29 includes an X-axis direction correcting actuator 30, a Y-axis direction correcting actuator 31, and a posture correcting actuator 32, and corrects the mounting position of the magnetic head 26 or its posture. The magnetic head 26 is connected to the microscope 33
Is to be observed by A television camera 34 is connected to the microscope 33 and this television camera
The video obtained at 34 is supplied to the control unit 28 via the image processing device 35.

In the configuration described above, when the magnetic head 26 is mounted on the rotary drum 24, the rotary drum 24 is placed on the base 23 and pressed against the base 23 by the presser fitting 25. In this state, the main shaft 14 is rotated 360 degrees. And the rotating drum with respect to the center of the base 23 at this time
The center position of 24 is detected by the circumferential runout detector 27. The information obtained here is transmitted to the control unit 28 comprising a computer.
Supplied to

Therefore, the magnetic head 26 is
When fixed to the base 24, the X-axis direction correction actuator 30, the Y-axis direction correction actuator 31, and the posture correction The actuator 33 moves the check 29 to move the magnetic head 26 to a correct position. This position is detected by the microscope 33 and fed back to the control unit 28 via the television camera 34 and the image processing device 35. And the magnetic head 26 in the correct position
Are fixed on the head drum 24 by screws.

After the mounting of the magnetic head 26 at the first position is completed, the head drum 24 is rotated by a predetermined angle, and the above operation is repeated at the next position to mount and fix the magnetic head 26. By repeating this operation by the number of magnetic heads 26, a plurality of magnetic heads 26 are mounted and fixed on the rotating drum 24. Then, in this state, the rotating drum 24 is removed from the base 23.

The feature of such a mounting device is that the circumferential deviation detector 27 detects the displacement of the center of the rotary drum 24 with respect to the center of the base 23, and the actuators 30, 31, and 32 respond to the detection to detect the displacement of the magnetic head 26. The magnetic head 26 is correctly mounted and fixed at a predetermined position on the drum 24 by correcting the mounting position with respect to the drum 24. By adopting such a method, the rotating drum 24 is mounted on the base 23. In order to overcome the conventional drawbacks due to the correct positioning at the center of the lens, namely, low angle division accuracy and poor workability.

This operation will be described in more detail. The head of this device 26
Is mounted by the center correction method.
As shown in the drawing, the center position (r, θ) of the rotating drum 24 with respect to the center (0, 0) of the base 23 is determined, and the position of the magnetic head 26 is shifted from the optical axis by rsin θ. It is assumed that. r and θ are obtained as follows. The circumferential runout detector 27 detects, for example, the distance between the outer peripheral surface of the head drum 24 and the gap by detecting the distance from the outer circumferential surface of the head drum 24 by the capacitance. As is clear from FIG. 2, h is given by: h = a−R + rcos θ = rcos θ + a−R (1) Here, considering the roundness S of the head drum 24, h = rcos θ + a−R ± S / 2 (2 ). Here, if the proportionality constant is assumed to be 1, the output voltage V of the runout detector 27 is V = −h = −rcos θ−a + R ± S / 2 (3) vessel
FIG. 3 shows a graph of the output voltage V of 27. And by dV / d [theta] seeks theta ₁ and theta ₂ becomes maximum, with V corresponding to both the average value _{(θ 1 + θ 2) /} 2 with obtaining the maximum value of V, the r from the maximum value of V You can ask. From the angle at that time, θ
Can be obtained. By using the extreme value of dV / dθ, the reading error of θ of the peak value of V is reduced.

By rotating the rotary drum 24 once, data as shown in FIG. 3 is obtained. From this data, the coordinates (r, r) of the center at each rotational position of the head drum 24 are obtained.
θ) can be determined accurately. The mounting position of the magnetic head 26 can be corrected by the actuators 30, 31, 32 according to the information on the position, and the magnetic head 26 is correctly mounted and fixed to the drum 24. When the amount of displacement of the head drum 24 with respect to the base 23 is smaller than 1/2 of the roundness S, θ ₁ shown in FIG.
θ ₂ has no meaning. In order to recognize the center of the drum 24 with high accuracy, it is preferable that the amount of displacement of the rotary drum 24 is set to a certain degree or more. The center is intentionally shifted, and the output of the circumferential runout detector 27 is Try to draw a cosine wave as shown in.

According to such a mounting device of the magnetic head 26, by performing the center correction of the rotating drum 24, the accuracy of the angle division is improved. As an example, conventionally ± 3.5μm
Was ± 2.5 μm with the device that visually recognizes the head, and ± 1.7 μm angle division accuracy with the device that performs head recognition by image processing. ing. In addition, by performing the center correction of the drum 24, workability is improved, and productivity is increased. In addition, it is possible to easily respond to a model change while maintaining high productivity, thereby preventing obsolescence of equipment. In addition, by simply changing the shape of the base 23, it can be applied to all rotating drums, and the efficiency of the equipment is improved. In addition, since it has an inspection function, self-checking becomes possible.

〔The invention's effect〕

As described above, the present invention detects the position of the center of the rotary drum with respect to the center of the base on the apparatus side, corrects the mounting position of the magnetic head according to this detection, and mounts the magnetic head on the rotary drum. It is like that. Therefore, the magnetic head can be accurately and efficiently attached and fixed to the rotating drum.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part showing a magnetic head mounting apparatus according to an embodiment of the present invention, FIG. 2 is an enlarged plan view of a main part showing a structure of a peripheral runout detecting section, and FIG. 6 is a graph showing the output of the vessel. The names of the main parts in the drawings are as follows. 14 ... Rotating spindle 17 ... Encoder 19 ... Motor 23 ... Base 24 ... Rotating drum 26 ... Magnetic head 27 ... Surround runout detector 28 ... Control unit 29 ... Chuck 30 ... X-axis direction Correction actuator 31 ... Y-axis direction correction actuator 32 ... Position correction actuator

Claims (1)

(57) [Claims] 1. A rotary drum is mounted on a base,
Detecting means for detecting a center position of the rotary drum with respect to a center of the base, wherein the magnetic head is mounted at a predetermined position on the rotary drum while rotating the rotary drum by a predetermined angle by the base; And a correcting means for correcting the mounting position of the magnetic head according to the center position of the rotary drum.