JPS6161759A - Curved surface polishing device for bar work - Google Patents

Abstract

PURPOSE:To dispense with curved surface polishing together with a core as well as to improve manufacturing efficiency ever so better, by performing the curved surface polishing for a top end surface of the core of a magnetic head for VTR with a bar work in a state of prior to being cut and separated into individual cores. CONSTITUTION:A bar work 23 made up of sticking both first and second core base materials together is set to a jig driving device 26 for a jig 25 locked with wax or the like. At this time, the jig 25 is supported by fulcrum shafts 27 and 28 and actuating rod 34 whereby this jig 25 poses in horizontality. Next, with a pulse motor of a first feed device 31, a rough feed table 53 and a grindstone 29 are made to come closer to the bar work 23 and the interval between them is measured. Then, operation of a oscillating motion mechanism and a slide reciprocation of a movable block 38 both are made to be carried out, making the jig 25 perform this oscillating motion, and voltage of a piezo-actuator 67 of a second feed device 32 is made to go up by degrees while making a polishing fluid discharge out of a nozzle, while a feed table 52 is fed to the right as far as the said interval and further feed it by a minute distance, thus curved surface grinding for a top end surface of the bar work 23 is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a curved surface polishing apparatus used for polishing a curved surface of the top end surface of a core of a magnetic head for a VTR, for example.

The structure of a magnetic head (1) for a conventional VTR will be explained with reference to the drawings. In the same figure, (2) is a magnetic gap between a first core member (3) and a second core member (4) made of ferrite, with a non-magnetic thin film (5) sandwiched between their opposing top end sides. The parts that form g and are joined to each other,
The core is bonded and integrated with glass (6), and the thickness is made thinner, especially in the vicinity of the magnetic gap g, to the size of the track width, and the recesses caused by the thinning are filled with the above-mentioned glass (6). . (7) and (8) are the winding insertion window (9) formed by cutting on the joint surface near the magnetic gear g of the first core member (3) and the first and second core members (3) ( 4) is formed by cutting the outer surface of the winding locking groove (10) (
11), the first and second core members (3)
(4) This is a coil wound around the coil. The top end surface (12) of the core (2) is a curved surface with a predetermined curvature to ensure smooth sliding contact with the magnetic tape, which is a magnetic recording medium.

Conventionally, the core (2) has been manufactured by the following steps.

First, a first core base material (13) as shown in FIG. 5 and a second core base material (14) as shown in FIG. 6 are manufactured.

These are made by cutting rectangular parallelepiped ferrite, and the first core base material (13) has cutting grooves (15 ) (15)-1 First long groove (16) for forming the winding insertion window (9), second long groove (17) for filling the adhesive glass, forming the winding locking groove (10) A third major key (18) is formed, and a second core matrix (18) is formed.
14) has line locking grooves (19) with cut grooves (19) having the same dimensions at symmetrical positions to the first core base material (13).
1) A third groove (20) is formed. Furthermore, non-magnetic thin films (21) (22) such as 5i02 are deposited on the joint end faces of the first and second core base materials (13) (14). Furthermore, this thin film (21) (22)
The sum of +g is the size of the gap g.

Next, the first and second core base materials (13) (14)
Align as shown in Fig. 7 and cut the cutting groove (15).
(15), -m-, (19) (19)-, and the second long groove (17) are filled with adhesive glass (6) and bonded together to form a bar (23).

Next, as shown in FIG. 8, the bar material (23) is sliced at a constant thickness using a rotary blade (not shown) to form individual cores (
2) Separate. This slice position is located at the cut groove (15) filled with glass (6) as shown by the dashed line in the figure.
This is the position where (19) is divided into two in the customer-servant direction.

Next, this single core (2) is fixed to a jig (not shown) with wax or the like, and the top end surface of the core (2) is polished into a curved surface using a running polishing tape (24) as shown in FIG. As a result, the core (2) is processed into the shape shown in FIG. The grating tape (24) is made of a resin film made of polyester or the like on which Fe, Cr, etc. are vapor-deposited.

60-2 In forming the above core (2), the top end surface is polished using a bar (
23) is cut and separated into individual cores (2), and then applied one by one to rLIl-polishing tape (24). This caused the following problem.

The first problem is that since a flexible polishing tape (24) is used, the polishing condition varies, making it difficult to match the size and shape of the polished surface to a certain standard, and making it difficult to make the characteristics of the magnetic head uniform. It is.

The second problem is that it is difficult to work because it is necessary to repeat the process of fixing the cut and separated micro-shaped cores (2) one by one to a jig with wax or the like, and then removing them after ωF polishing. This is inappropriate for a nine-year production system.

The present invention was made in order to solve the above-mentioned problems when polishing the top end surface of each cut and separated core using a polishing tape. To provide an apparatus for precisely polishing a curved top end surface of a bar using a rotary grindstone at the stage before it is processed.

The present invention has a jig drive mechanism that reciprocates in the axial direction of a jig having a rocking ring and a liver material to be ground fixed at one end, and a jig drive mechanism that rotates parallel to the rocking axis of the jig. A fine movement feeder that moves a rotary grindstone having a shaft and a polishing surface on its circumferential surface, and a coarse movement feeder that supports the fine movement feeder and moves the outer peripheral surface of the grindstone to a position close to the material to be polished. This is a bar material curved surface gf polishing device characterized by comprising:

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In the figure, (25) is a jig with a rod (material to be polished) (23) as shown in Figure 7 fixed to its tip with wax, etc., and (26) is a jig with the jig (25) as a pivot. (oscillation it [
l) Swing luck ω around (27) (28)
The jig drive mechanism (29) has a rotating shaft (30) parallel to the sliding direction and rotates the magnetic hend core before slicing it on its circumferential surface. 5. Polishing the bar (23) in the state of 5. The whetstone (31) is turned and the whetstone (29) is turned into a bar (2
3) The first feeding device (roughing J feeding device) sends the rotary grindstone (29) to the position approaching the bar (23).
This is a precise second feeding device (fine movement feeding device) that feeds from the approach position to the final position of ωF polishing.

The above configuration will be explained in detail.

The jig (25) is a rectangular parallelepiped block, and has a pair of holes (33) (33) (33) on the sides into which the cone 733 at the tip of the support shaft (27) (28) is inserted, and an actuator that provides rotational force for swinging motion. Hole (3) into which the conical end of the rod (34) is inserted.
5) is perforated. The bar material (23) is attached to this jig (25
) on the front end of the longitudinal direction! lll (27) (2
8) and fixed with wax in a state in which the polished surface is projected.

The jig group movement mechanism (26) moves the jig (25) onto a movable base (38) which is slidably held on the first base (36) via guide rails (37) (37). ) from both sides! j1 (27) (28) and an oscillation mechanism (39) that oscillates the jig (25) using an operating rod (34). The movable table (38) is moved to the first base (36) by a drive source (not shown).
) makes a horizontal sliding movement of a certain width. Also, one spindle (27) is fixed on the movable table (38), while the other spindle (28) protrudes into and out of its support (40) in order to attach and detach the jig (25). Possibly supported.

The swing movement Q mechanism (39) has an operating rod (34) in the intermediate position.
) is attached to the first bearing (4).
2) is fixed to a first rotating shaft (43) supported on a movable base (38) via a second bearing (44), and the other end is supported on a movable base (38) via a second bearing (44). The bin (46) and the third bearing (46) extend eccentrically from the rotating shaft (45) of the
47). This oscillating movement mechanism (39) rotates the rotational movement of the second rotating shaft (45) into the arm (
41), and causes the jig (25) to swing around the support shaft (27) (2B) using the operating rod (34).

The rotary grindstone (29) has two holding fittings (49) fitted to the rotating shaft (30) of the air spindle (48).
50), and are fixed by tightening them with a nut (51) screwed onto the rotating shaft (30). The air spindle (48) is fixed on the precision feed table (52), and the rotating shaft (30) protruding from the other end of the air spindle (48) is mounted on the coarse feed table (53) with a predetermined thickness of anti-vibration material. Electric motor (55) fixed via rubber (54)
Output hill (56) and pulley (57) (5B)
and Heald (59). The coarse feed table (53) is slidably supported on the second base (60) by guide supports (61) (61).
The precision feed table (52) is slidably supported on the coarse feed table (53) via guide rails (62) (62).

The first Ii'& dynamic feed device (31) consists of two slide slides (63) fixed to the rough feed table (53).
(63') is screwed with a ball 1 (64) which is rotationally driven by a pulse motor (not shown), and the pulse motor sends the i2 feed bull (53). This slide block (G3) (6:))
is guided and supported by two parallel guides (61) on both sides of the ball screw (64).

The second fine feed device (32) that performs precision feed is attached to the first and second brackets (65) so as to connect the coarse feed table (53) and the precision feed table (52).
The driving source is a piezoelectric actuator (67) which is fixed between the two using the piezoelectric actuator (66) with the direction of expansion and contraction being horizontal. This piezoelectric actuator (67) is constructed by, for example, stacking piezoelectric materials in multiple layers with internal electrodes in between, and connecting every other internal electrode so that a common voltage is applied to each layer. The electrodes are drawn out, and when a DC voltage is applied, the length in the stacking direction changes in proportion to the voltage. This change characteristic has hysteresis, but in the present invention, only the positioning when stretching and pressing the rotating grindstone (29) against the bar (23) is a problem, so even if this characteristic exists, the piezoelectric The features of the actuator (67), such as being small and lightweight, capable of highly accurate minute positioning, low noise, and high conversion efficiency (50% or more) from electrical energy to mechanical energy, are all taken advantage of. Since this piezoelectric actuator (67) is of a laminated type, it can have a large displacement, and with a resolution of about 100 A, a displacement of several μm to several +lf can be accurately obtained by changing the applied voltage.

In addition, it is fixedly installed above the air spindle (, 18),
A nozzle (68) extending toward the r4IF polishing position is for supplying polishing liquid.

The bamboo curved surface polishing device (69) of Kyosei operates as follows.

A coarse feeding table (53) and a precision feeding table (52) are provided by the first and second feeding devices (31) (32).
) is moved back to the left side in Figure 1, and as shown in Figure 7, the rod (23) formed by bonding the first and second core base materials (+3) (14) together is coated with wax, etc. The jig (25) fixed at Then, fit the conical tips of the spindle (27) and the operating rod (34) into the holes (33) and (34) drilled on one side of the jig (25), and then let the spindle (28) protrude again. hole (3 holes) drilled on the other side.
3). To install this jig (25),
The central axes of the support shaft (27) and the operating rod (34) are in a horizontal plane, and the attached jig (25) is in a horizontal position.

Next, the ball screw (64) is rotated by the pulse motor of the first feeder (31), and the coarse feed table (53) is rotated.
is advanced to the right in FIG. 1, and the rotary grindstone (29) is sent to a position close to the bar (23). Next, the rotary grindstone (29) and the bar (23) are separated using a laser distance measuring device (not shown) or the like.
Measure the distance between. Then, the oscillation mechanism (39) is activated and the movable table (3rd) starts sliding back and forth,
Swinging IJJ to the jig (25) that fixed the bar material (23)
while discharging the polishing liquid from the nozzle (68), the piezoelectric actuator (6) of the second feeding device (32)
7), the precision feed table (52) is sent to the right in Fig. 1 by the distance measured by the laser beam, and then the precision feed table (52) is moved to the right by the distance measured by the laser beam.
Send m. As a result, the rotating grindstone (29) is
Polish the top end surface to a curved surface. At this time, the head swing back 1
The three machines (38) equipped with the mechanism (39) are rotary grindstones (
Step 5 of 29): Since the slide is reciprocated in a direction parallel to the rod (30), the curved surface polishing is performed uniformly in the longitudinal direction of the bar (23).

When the curved surface polishing is completed as described above, the first and second
The feeding devices (31) and (32) are moved to the left in FIG. 1, the swinging motion, sliding reciprocating motion, and discharge of the polishing liquid are stopped, and the jig (25) is removed. Then, remove the polished bar (23) from this jig (25) by melting the wax, slice it at a predetermined position as shown in Figure 8, and cut and separate it into the throat core (2). do.

In addition, in the above embodiment, the IJ of the second feeding device (32)
The piezoelectric actuator (67) used as the source may be replaced with another device capable of fine Bj fine movement, for example, a mechanical device.

Also, by shifting the first sharpening uf rear support ψd+ (27) (28) with respect to the jig (25), the swing radius of the jig is changed,
By performing the second g-polishing, it is also possible to change the curvature of the curved surface near the center of the bar (23) and the curvature of the curved surface near the side wall.

In the present invention, the curved surface of the top end surface of the core of a VTR magnetic head is polished in the state of a bar before being cut and separated into individual cores, so curved surface polishing for each core is not required, and manufacturing efficiency is improved. It is suitable for mass production. In addition, since curved surface polishing is performed using a rotating grindstone while the jig is oscillating and sliding, there is no instability that occurs when polishing with a polishing tape, and the polished shape can be finished to the designed dimensions. The characteristics of the head can be made uniform and the yield can be improved.

Furthermore, since the feeding of the grinding wheel is divided into two stages using the first feeding device and the precise second feeding device,
It is possible to simultaneously satisfy the two contradictory demands of higher processing speed and higher precision.

[Brief explanation of drawings]

1 to 3 are a front view, a plan view, and a side view, respectively, of an apparatus according to an embodiment of the present invention. FIG. 4 is a perspective view showing an example of an air head using a core manufactured according to the present invention. FIGS. 5 to 9 are perspective views showing the conventional core molding method in the order of steps. FIGS. 5 and 6 show the first and second core base materials, and FIG. Figure 8 shows the first piece formed by bonding together the core base materials.
Each figure shows the state of polishing a curved surface with gf field tape. (23) - Bar material, (25) - Jig, (26) -
・Jig drive mechanism, (27) (28) - Support shaft [turn S lino shaft], (29)... Single rotation grindstone, (30) - Rotary shaft, (31) - Coarse feed device [1st feeding device], (
32) - Fine J feed device [second feed device].

Claims (1)

[Claims] (1) A jig drive mechanism that reciprocates a jig with a swing axis and a material to be polished fixed to one end in the direction of the swing axis, and a jig drive mechanism that has a rotation axis parallel to the swing axis of the jig and has a circumferential surface. The present invention is characterized by comprising: a fine movement feeder that minutely moves a rotary grindstone having a polishing surface of Curved surface polishing device for bar materials.