JPH0146921B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new and improved magnetic head tape running surface polishing apparatus.

Generally, the playback efficiency η of a ferrite magnetic head for VTR video is expressed as η=(g/D)/(g/D+9.8/μs) (g: gap radiation, D: depth, μs: effective magnetic permeability). In order to maintain high and stable regeneration efficiency, dimensional control of the fat D is considered to be particularly important. Making this depth dimension uniform is very effective in adjusting various electrical characteristics of the VTR, and for this reason, this depth dimension is made by polishing the tape running surface into an arcuate surface during the manufacturing process of the magnetic head chip. They are all prepared. In addition, magnetic head chips are usually made into single pieces by cutting a long and thin block-like body made in advance, but since it is extremely difficult to accurately control the depth of the block, it is difficult to control the depth after cutting it into pieces from the block. The current situation is that it is regulated.

Conventionally, in order to polish the tape running surface of a magnetic head chip in order to regulate the depth described above, first, the portion of a prefabricated block that will become the tape running surface is ground with a cylindrical grinder to form a desired circular arc surface, and then this The blocks are cut into individual head chips, which are individually attached to a predetermined base plate, and the base plate is arranged radially on a predetermined disk so that the tape running surface of the head chips is located on the outer periphery. The disk is attached to a rotating cylinder, and an abrasive tape is wrapped around its outer circumference.The cylinder is rotated so that a new tape surface is exposed one after another, and the tape running surface of the head tip that slightly protrudes from the outer circumferential surface of the cylinder is polished. In other words, the head chip obtained by cutting the block is actually assembled into the VTR.
A method has been adopted in which the tape running surface of the head chip is polished by bringing an abrasive tape into contact with it under conditions similar to those in which it is in contact with a VTR tape.

However, the individual head chips obtained by cutting the block have large variations in their depth dimensions, and the polishing time for subsequent depth adjustment varies, so the conventionally known polishing method described above is difficult to manage. In addition, when the initial depth dimension is large, it is difficult for the tape running surface of the head chip to form the desired circular arc surface, and there are disadvantages and disadvantages such as the head cap not making good contact with the magnetic tape when it is incorporated into a VTR. It was hot.

The present invention provides a new and improved tape running surface polishing device for a magnetic head capable of solving the disadvantages and shortcomings of the conventional method, which consists of a. a rocking table supported between both free ends of a plate spring, b a mechanism for swinging the rocking table, c a column having a magnetic head tip to be polished attached to one end thereof and fixed to the machine base at the other end; loosely fit into the
at least one magnetic head chip holder pivotally supported on the rocking table so as to be rotatable along the central axis of the arcuate surface to appear on the tape running surface of the head chip; d a rocking direction of the rocking table; a long abrasive tape that is movable in a direction intersecting with the tape running surface of the head tip and is disposed opposite to the tape running surface of the head tip; e. It is characterized by comprising a pressing surface plate that is brought into pressure contact.

Hereinafter, the present invention will be described in detail based on the accompanying drawings.

The drawings all illustrate a typical embodiment of the device of the present invention, and FIG. 1 is a schematic elevational view of the device, FIG. 2 is a plan view of essential parts of the device, and FIG. 3 is a schematic side view. FIG. 4 is a perspective view of a magnetic head chip processed by this apparatus.

As is clear from FIGS. 1 to 3, this device consists of a rocking table 2 carrying a magnetic head chip 1 to be polished.
, a swinging mechanism 3, a holder 4 for holding the magnetic head tip, a long abrasive tape 5, and a pressing surface plate 6 for pressing the abrasive tape against the tape running surface of the magnetic head tip. It is something.

The swing table 2 in this device consists of two mutually parallel leaf springs 2 each having one end fixed to the machine stand 7a.
It is supported between both free ends 21a and 22b of 1 and 22, and is connected to a swinging mechanism 3 to swing in the left-right direction in FIG. It moves by ΔW in the vertical direction by Δh, so strictly speaking it performs an arcuate swinging motion.

Further, the swinging mechanism 3 in this device consists of a motor 31, an eccentric wheel 32 attached to its shaft, and a lever 33. The lever 33 is pivotally supported by the machine base 7b at an intermediate position, and one end thereof is supported by the machine base 7b. It is loosely connected to the pin 32a of the eccentric wheel, and the other end is rotatably connected to the bracket 23 of the rocking table, so that the rotation of the motor 31 is controlled by the lever 3.
3, the rocking table 2 is rocked by changing the movement to a reciprocating motion. Note that any conventionally known rocking mechanism may be employed as the rocking mechanism 3.

Next, regarding the holders 4 for the magnetic head chips to be polished, one or more holders are removably mounted on the rocking table 2 via a suitable mounting surface plate 24. Each of these holders has one end 4a.
Attach the magnetic head tip 1 to be polished to the other end 4b.
The support 4 fixed to the machine base 7b in the loose fitting hole 41 provided in the
2 are inserted and loosely fitted together, and the holder itself is pivotally supported so as to be rotatable in a plane with respect to the mounting surface plate 24. The details of how each holder 4 is attached to the surface plate 24 are not shown in the drawings, but this can be done by, for example, providing a through hole in the holder 4, inserting a bolt-shaped spindle into the through hole, and attaching the tip of the holder 4 to the surface plate 24. It is rotatably mounted by screwing into the panel surface. The rotation axis 43 of each holder 4 needs to be aligned with the center axis of the circular arc surface that should appear on the tape running surface 1a of the magnetic head chip 1. When the pivoting shaft 43 swings in the left-right direction in FIG. Then, the tape running surface 1a of the magnetic head chip 1 attached to one end of the holder 4 comes into contact with the surface of the abrasive tape 5 disposed opposite to it, and runs on the surface of the tape from side to side, more precisely in a circle. The desired arcuate surface is polished by moving in an arc.

The abrasive tape 5 has, for example, GC on its surface.
It consists of a long film-like tape to which #6000 abrasive grains are adhered, and as shown in Fig. 3, it is sequentially fed out from a reel 51 disposed in front of the magnetic head 1 to be polished, which is mounted on a rocking table. and the guide roller 5
2, 53, the polishing tape 5 is taken up by a pinch roller 54 via a pressing surface plate 6, and as a result, the polishing tape 5 is continuously supplied so that a new surface of the polishing tape 5 is always placed in front of the magnetic head 1 to be polished.

Furthermore, regarding the pressing surface plate 6, this is used to bring the polishing tape 5 into contact with the tape running surface of the magnetic head 1 to be polished with an appropriate pressing force, and is used, for example, by a stage feeding motor. A linear scale 63 is attached to the tip of a carriage 62 that is reciprocated by a slider 61, and a linear scale 63 measures the distance from the swing table 2, in other words, the desired depth 1b on the tape running surface 1a of the magnetic head to be polished. is detected, and after reaching a preset depth value, the process is controlled so that it automatically returns to its original position after a spark-out period.

Next, the operation of the apparatus of the present invention will be explained. In order to polish the tape running surface 1a of the magnetic head chip 1 with this apparatus, the magnetic head chip 1 to be polished is first placed in a suitable manner before being attached to the holder 4. Attach it to the base plate 44. At this time, the head tip 1 is attached to the bottom side 4 of the base plate 44.
4a as a reference, the lower part 1c of the depth 1b is accurately positioned and pasted at a certain height under a microscope. Next, the base plate 44 is fixed to the holder 4 which is pivotally supported on the rocking table, with the base plate 44 as a reference.

After one or more magnetic head chips 1 to be polished have been mounted on the rocking table 2 in this way, the motor 31 of the drive mechanism is activated, and while the polishing tape 5 is continuously supplied, the stage The feeding motor 61 is activated, the pressing surface plate 6 is brought close to the rocking table 2, the polishing tape 5 is pressed against the tape running surface 1a of the magnetic head chip 1, and polishing is started.

During the polishing operation, the tape running surface 1a of the magnetic head tip undergoes an arc-shaped movement that is a combination of the rocking movement of the rocking table 2 and the rotational movement of the holder 4 about the rotation axis 43, and As a result, the tape running surface 1a of the head tip is polished along an arcuate surface centered on the rotation axis 43. Further, since the head tip 1 repeats the vertical movement of Δh through the swing motion of the swinging width 2ΔW by the rocking table 2, the running surface of the head chip is 1a is polished so that its arcuate surface also has a slight bulge in the axial direction.

The polishing work of the tape running surface of the magnetic head tip is continued while determining the depth 1b of the tape running surface using the linear scale 63 of the pressing surface plate 6.
When it is detected that the depth has reached the desired value,
The polishing cycle is ended by immediately stopping the polishing operation and then removing the polished magnetic head chip from the rocking table 2.

As explained above, according to the apparatus of the present invention, a plurality of magnetic head chips to be polished can be quickly and easily attached to and removed from the apparatus, and the depth dimension of each magnetic head chip to be polished on the tape running surface can be determined accurately and reliably. The practical value of this method is extremely great, as it can significantly improve the polishing efficiency and product yield, and also significantly reduce the polishing cost.

[Brief explanation of drawings]

FIG. 1 is a schematic elevational view of a polishing device according to the present invention;
FIG. 2 is an enlarged plan view of the main part, and FIG. 3 is a schematic side view. FIG. 4 is a perspective view of a magnetic head chip polished by the polishing device. 1... Magnetic head chip to be polished, 1a... Tape running surface, 1b... Depth dimension, 2... Rocking table, 21, 2
2... Leaf spring, 23... Bracket, 24... Mounting surface plate, 3... Rocking mechanism, 31... Motor, 32... Eccentric wheel, 33... Lever, 4... Head tip holder, 4
1... Loose fitting hole, 42... Fixed column, 43... Rotating shaft, 4
4... Base plate, 5... Abrasive tape, 51... Tape reel, 52, 53... Guide roller, 54...
Pinch roller, 6...pressing surface plate, 61...stage feed motor, 62...reciprocating table, 63...linear scale.

Claims (1)

[Scope of Claims] 1 a. A rocking table supported between both free ends of two mutually parallel leaf springs fixed to a machine base, b. A mechanism for swinging the rocking table, c. One end thereof. Attach the magnetic head tip to be polished to the head, and loosely connect the other end to the column fixed to the machine base.
at least one magnetic head chip holder pivotally supported on the rocking table so as to be rotatable along the central axis of the arcuate surface to appear on the tape running surface of the head chip; d a rocking direction of the rocking table; a long abrasive tape that is movable in a direction intersecting with the tape running surface of the head tip and is disposed opposite to the tape running surface of the head tip; e. A tape running surface polishing device for a magnetic head, comprising a pressing surface plate that is brought into pressure contact.