CN1139915C - Magnetic head front grinding device and method - Google Patents

Abstract

The presnet invention relates to polishing apparatus and polishing methods of magnetic head front surface. Rotational center holes are respectively formed on the upper surface and bottom of a polishing jig so that the jig can be fitted to a polishing device selectively upside down. In the case of a multihead mounting two magnetic heads 4 on one head base, new contact width between the heads 4 and a polishing tape can be regulated in accordance with necessary polishing quantity by rotating the polishing jig fitted to the head base forward and reversely and fitting the jig upside down to execute front polishing by the polishing tape, so that gap can be finished at a desired depth by batch front polishing. Consequently assembling manhours can be reduced and the cost can also be reduced.

Description

Magnetic head front grinding device and method thereof

Technical field

The present invention relates to magnetic head front grinding device and methods thereof such as VTR, be specifically related to that a plurality of magnetic heads are fixed on a multihead front on the magnetic head seat and grind.

Background technology

In recent years, require to provide device small-sized, high image quality in digital VTR field.For realizing this kind high image quality, be necessary to realize forcing down the high data ratio of compressed signal, the multiple recording technology of reproduction is write down signal allocation in widespread use to a plurality of passages.

In addition, in the multiple recording of rotating magnetic head mode that with VTR is representative, from the restriction in space, a plurality of magnetic heads are installed in a multihead on the magnetic head seat has become main flow.But, in the multihead structure, the serious problems when existing the head gap and being finish-machined to the prescribed depth operation and taking a lot of work very much.The gap depth of magnetic head exists favourable as far as possible deeply to set for from the life-span viewpoint, yet from the inverse relationship of electromagnetic conversion characteristics viewpoint excellent in efficiency when shallow.In nearest high image quality VTR, magnetic head is required high-performance, in the very low range (for example 15-18 micron) that requires gap depth to be set in to take into account above-mentioned two aspects simultaneously.

In the past, as an example of this type of conventional art known have establish the sand belt ways in the magnetic head both sides and carry out multihead front abrasive method and multihead (Japanese patent laid-open 6-301916 communique).But, on problems such as effective utilization of the trickle adjustment of ways, sand belt and milling time, can not negate to be difficult to realize.

Below, with aftermentioned Fig. 3 and Figure 10 traditional magnetic head front grinding device is described.As shown in figure 10, traditional magnetic head front grinding device is made of cylindric lapping apparatus 101, lapping device 102 and sand belt 103.Cylindric lapping apparatus 101 by the top of as shown in Figure 3 the magnetic head 4L, the 4R that make multihead slightly from the cylinder periphery stretch out, releasably maintained magnetic head maintaining part 101a constitutes.Be set to be installed in the rotation center hole of using on the lapping device 102 on the bottom surface of lapping apparatus 101, the lapping apparatus 101 that multihead will be installed by this rotation center hole is installed on the lapping device 102.Lapping device 102 possesses turntable 106 of lapping apparatus 101 being installed and being made rotation and the sand belt drive division (not shown) that sand belt 103 is walked with certain speed to a direction (arrow F direction).Rotating dog 106a chimeric with the rotation center of lapping apparatus 101, that make lapping apparatus 101 rotations is set on turntable 106.

When making lapping apparatus 101 rotations that multihead is installed, sand belt 103 contacts with the top of magnetic head 4 and grinds.In addition, lapping device 102 makes sand belt 103 from the top down with the certain speed walking, and lapping apparatus 101 is ground along the identical time with opposite spin of positive dirction respectively.In addition, two magnetic head 4L, 4R carry out the degree varies sample that grind in the gap.This just produces tens of microns difference at the height of multihead function aspects two magnetic heads.Because the magnetic head 4L of sand belt 103 direction of travel, upstream side is many because of contacting with the new abrasive surface of sand belt 103 relatively, makes amount of grinding many.Figure 11 represents the operation of traditional front Ginding process.

Like this, owing to can not control amount of grinding, so exist the problem that the finishing of multihead gap depth can not be reached desired value.At this problem, consider to change the rotating time of lapping apparatus 101, yet, when bigger change forward and backward ratio, will take place that magnetic head 4L, 4R vertex position depart from assigned position and impracticable.Therefore, in the classic method, the magnetic head 4 that temporarily is fixed on the interim seat is carried out after grind the front magnetic head 4 being unloaded, be attached at once more on the magnetic head seat, individually carry out the front and grind, when adopting this method to take a lot of work very much.

In sum, traditional magnetic head front grinding device exists and the finishing of multihead gap depth can not be reached the desired value problem.In addition, for finishing reach desired value have to take to magnetic head carry out individually the front grind after with head unload, be attached at this on magnetic head seat method when taking a lot of work very much once more.

Summary of the invention

Therefore, the present invention is just for addressing the above problem, for with multihead, especially two magnetic heads are installed in a structure on the magnetic head seat, not only provide to need not to carry out individually the front grinding and can once carry out good magnetic head front grinding device and the Ginding process thereof of productivity that desired value was ground and gap depth can be refined in the front.

In addition, the present invention have be located at above the cylinder and the bottom surface on concentric rotating center section and for the top with a plurality of magnetic heads keeps becoming the magnetic head maintaining part of stretching out from the cylinder outer peripheral face, and distance till possessing from the cylinder bottom surface to magnetic head and the distance lapping apparatus about equally till the magnetic head above cylinder; Or possesses lapping apparatus with different a plurality of magnetic head maintaining parts that tilt.According to the present invention, because by select the formal dress/upside-down mounting of lapping apparatus according to the initial stage head gap degree of depth, or by the magnetic head seat being changed the outfit on the magnetic head maintaining part that difference tilts, it is wide that regulation magnetic head and sand belt new contacts, thus energy finishing and reach the gap depth of desired value.

Magnetic head front grinding device of the present invention is installed in lapping magnetic heads on the cylindric lapping apparatus, lapping apparatus is installed on the turntable that can just change and reverse, make lapping apparatus rotation and move with front and grind magnetic head relative to sand belt, it is characterized in that, lapping apparatus is provided with the rotating center section that upside-down mounting is used in the above, on the bottom surface, be provided with simultaneously the rotating center section that formal dress is used, two rotating center section are provided with one heart, turntable has the turning axle with the rotating center section intercalation of top or bottom surface, and sets for from the bottom surface of lapping apparatus identical with the distance to magnetic head above lapping apparatus to the distance of magnetic head.

Magnetic head front grinding device of the present invention, it is characterized in that, lapping apparatus grinds seat, housing and clamping ring by cylindric front and constitutes, cylindric front is ground seat and can be remained under the state on the guide part and rotate will being fixed in magnetic head on the magnetic head seat, housing inserts in front grinding seat outward and goes up and the magnetic head seat is pushed on guide part, and clamping ring clamps housing on the assigned position of magnetic head arrival guide part.

Magnetic head front grinding device of the present invention, it is characterized in that, the front is ground a bottom by large diameter top and minor diameter and is formed, and the maximum outside diameter that constitutes housing is identical with the external diameter of described large-diameter portion, in the time of on the minor diameter of the housing extrapolation being ground in front seat, it is identical with the external diameter of housing that seat is ground in the front, is the lapping apparatus of integrated outward appearance.

Magnetic head front grinding device of the present invention is characterized in that, under the state that clamps with clamping ring, top and housing top that seat is ground in the front becomes same plane.

Magnetic head front grinding device of the present invention is characterized in that, on the top and bottom surface of grinding seat a plurality of concentric rotation drive holes is set respectively in front.

Magnetic head front Ginding process of the present invention, be installed on the lapping apparatus at the multihead that will grind, make lapping apparatus rotation and relatively sand belt move when carrying out the front grinding of multihead, it is characterized in that, multihead is installed on the distance set for from the bottom surface to this multihead and the equidistant lapping apparatus from top to this multihead, make then the rotation of this lapping apparatus and relatively sand belt move to carry out the front grinding of multihead, and the gap depth that compares each magnetic head, then in grinding with the lapping apparatus upside-down mounting, make its rotation and move to grind with respect to sand belt, in process of lapping, become the formal dress state to carry out forward and reverse the relative front grinding device of lapping apparatus, and then become the upside-down mounting state to carry out forward and reverse again.

Magnetic head front Ginding process of the present invention is characterized in that, the rotational time of the lapping apparatus of formal dress state equates that with the rotational time of upside-down mounting state the just commentaries on classics time of each state and reversing time are by measuring the gap depth decision.

According to the present invention as described hereinbefore, when the front that two magnetic heads is installed in a multihead on the magnetic head seat is ground, because by according to amount of grinding lapping apparatus being carried out formal dress/upside-down mounting respectively, perhaps the magnetic head seat is changed the outfit on the magnetic head maintaining part that difference tilts, can stipulate the new contact width of magnetic head and sand belt, thereby energy finishing reaches the gap depth of desired value.For example, for the primary clearance depth offset of two magnetic heads 4, can realize gap depth finishing is reached identical.In view of the above, owing to need not magnetic head front is ground individually, and can once a plurality of magnetic head fronts be ground, reduce assembling procedure, reduce cost thereby can reach.

Description of drawings

Simple declaration to accompanying drawing.

Fig. 1 is the stereographic map of the lapping apparatus of the present invention's the 1st embodiment magnetic head front grinding device,

Fig. 2 is the cut-open view of the lapping apparatus of device shown in Figure 1,

Fig. 3 is the multihead stereographic map,

Fig. 4 is the stereographic map of the lapping apparatus of the present invention's the 1st embodiment magnetic head front grinding device,

Magnetic head scanned track when Fig. 5 was just changeing for the present invention the 1st embodiment,

Magnetic head scanned track when Fig. 6 reversed for the present invention the 1st embodiment,

Fig. 7 is the stereographic map of the lapping apparatus of the present invention's the 2nd embodiment magnetic head front grinding device,

Fig. 8 is the stretch-out view of the present invention's the 2nd embodiment magnetic head front grinding device lapping apparatus,

Fig. 9 is the process chart of the present invention's the 1st embodiment method,

Figure 10 is the stereographic map of traditional magnetic head front grinding device,

Figure 11 is the process chart of traditional front Ginding process.

Embodiment

Following with reference to Fig. 1-9 explanation various embodiments of the present invention.

Fig. 1-6 and Fig. 9 represent the embodiment of the invention 1.As shown in Figure 1 and Figure 2, the lapping apparatus of magnetic head front grinding device of the present invention is made of front grinding seat 1, housing 2 and clamping ring 3.Grind in front and form on the seat 1 by the guide part 1a of 5 pairs of magnetic heads of magnetic head seat, 4 location and the rotation center hole 1b of concentric setting on 1f and the bottom surface 1e on cylinder respectively.In addition, form the V-shaped groove 1d that the housing 2 that inserts on this cylinder top is fixed on the cylinder upper periphery of grinding seat 1 in front.Push rubber 2a and near hard sphere 2b movably radially week in the cylinder of housing 2 with what be located at that magnetic head seat 5 on the guide part 1a pushes maintenance being provided with on the housing 2, meanwhile, as shown in Figure 2, the hold-down ring 3 that is embedded in the cylinder periphery of housing 2 is outward constituted and can slide along axial rotary.

As shown in Figure 3, two magnetic heads 4 are fixed on the magnetic head seat 5.Stipulating two magnetic head 4L and magnetic head 4R relative position by high precision, in short transverse, is that tens of microns states are fixed at illustrated h3.

With fix two magnetic heads 4 multihead, make magnetic head seat 5 reference field downwards (magnetic head 4 is downward) be arranged on the front and grind on the guide part 1a of seat 1.Then, housing 2 is ground the top of seat 1 from the front and insert, be pressed into and make multihead consistent with the phase place of pushing rubber 2a.When further housing 2 is pressed into, multihead because of push rubber 2a be pressed fixing, grind the position of the V-shaped groove 1d of seat 1 when hard sphere 2b arrives the front, make clamping ring 3 grind a seat bottom direction along the front to slide.Because of the slip of clamping ring 3, hard sphere 2b is pressed into V-shaped groove 1d, housing 2 is fixing, finishes multihead and install.At this moment, constitute with cylinder bottom surface 1e to the distance H 1 of magnetic head 4 and above cylinder to the distance H 2 of magnetic head about equally.But, as above-mentioned, since magnetic head 4L different with the height of magnetic head 4R, make the distance of H1 more elongated in magnetic head 4L side.In addition, formation makes the top of two magnetic heads 4 stretch out equal extent from cylinder curved surface periphery.In addition, the separation of distance H 1 and distance H 2 is preferably the mid point by the center line at each center of short transverse of magnetic head 4L, 4R, H1=H2.

To keep the lapping apparatus of multihead to be installed on the lapping device shown in Figure 4.But lapping device possesses turntable 6, the sand belt 7 of positive dirction and opposite spin.The driving shaft 6b that is intercalated in the turning axle 6a of lapping apparatus rotation center hole 1b and is intercalated in rotation drive hole 1c, transmitting rotary power is set on turntable 6.The bottom surface 1e that is mounted to lapping apparatus now contacts (claiming that this is a formal dress) with turntable 6.When started by press button 8, walk along arrow F direction with turntable 6 when beginning to rotate, sand belt 7.The top of magnetic head 4 contacts with sand belt 7, scans thereon and carries out the front grinding.Turntable 6 is just changeing the counter-rotating certain hour respectively, according to target is worth amount of grinding and makes this circulation repeatedly.With turntable 6 when arrow J direction is rotated as just change, in contrast as counter-rotating.

Then, magnetic head 4 being scanned track on sand belt 7 describes.Fig. 5 and Fig. 6 represent respectively that turntable 6 is just changeing, magnetic head 4L, 4R when reversing scan track.When turntable 6 is just changeing, as shown in Figure 5, because magnetic head 4R than magnetic head 4L in advance, magnetic head 4R is the overall with R1 of magnetic head 4R with the width (wide to call new contact in the following text) that new sand belt 7 contact, and the wide magnetic head 4R that is gone ahead of the rest because of the quilt part that accounts for that newly contacts of another magnetic head 4L becomes L1.Because the grainding capacity of sand belt 7 is the highest with new abrasive surface, magnetic head 4 once scans partly more greatly, grainding capacity is low, and the wide difference of this new contact becomes the poor of grinding rate.Be exactly, at this state, because R1＞L1, the amount of grinding of magnetic head 4R is many, and the amount of grinding of magnetic head 4L is few.When turntable 6 counter-rotatings, as shown in Figure 6, because magnetic head 4L in advance, because of the wide L2 of new contact of magnetic head 4L is big, the wide R2 of new contact of magnetic head 4R is little, and the amount of grinding of magnetic head 4L is many.Because turntable 6 shows the rotating repeatedly of identical time greatly, final amount of grinding relatively be L1+L2 and R1+R2.As shown in scheming obviously, L1+L2＞R1+R2, the amount of grinding of magnetic head 4L is many, and the amount of grinding of magnetic head 4R is few.In addition, clearly, the ratio of the amount of grinding of two magnetic heads 4 changes with the rotational speed of turntable 6 and the traveling speed of sand belt.

For contacting cylinder to be stood upside down be installed in, the top and turntable 6 that makes lapping apparatus carries out front grinding (claiming that this is upside-down mounting) on the lapping device.By above-mentioned principle, the amount of grinding of this magnetic head 4R is many, and the amount of grinding of magnetic head 4L is few.

Like this, carrying out the front when grinding to two magnetic heads 4 being installed in multihead on the 1 magnetic head seat 5, by measuring the primary clearance degree of depth, amount of grinding until the gap depth that calculates desired value, corresponding therewith, the front grinding is carried out in the formal dress/upside-down mounting of selected lapping apparatus, and energy finishing reaches the gap depth of desired value.In addition,, can make the magnetic head front shape after the grinding of front good, not produce that curvature is lost shape or apex offset because present embodiment just changes/reverse with the roughly the same time respectively.Fig. 9 is the process flow diagram of the method for this embodiment 1 of expression.

In addition, more than a multihead that is installed on the lapping apparatus is illustrated, yet also can implement a plurality of multiheads are installed on the lapping apparatus, once carry out the higher method of so-called throughput rate of grinding previously, in this occasion, be necessary to consider that new contact is wide, the rotational speed of turntable 6 and the traveling speed of sand belt 7 are adjusted to optimization.

Fig. 7, Fig. 8 represent embodiment 2.As shown in Figure 7, the lapping apparatus of magnetic head front grinding device of the present invention constitutes by grinding seat 11 and housing 12.Grind guide part 11a, the 11b, 11c, the 11d that carry out magnetic head 4 location on the seat 11 respectively by 90 ° of formation of phase differential by magnetic head seat 5 in front.Fig. 8 is from arrow K direction shown in Figure 7, the front is ground the figure of the cylinder curved surface expansion of seat 11, the magnetic head seat carrying plane of each guide part is not parallel with the bottom surface 11e of front grinding seat 11, formation (is above-mentioned guide part from the magnetic head maintaining part, as follows) tiltangle of the Plane of rotation of 11a is inequality with the inclination angle [theta] from the Plane of rotation of magnetic head maintaining part 11b, inequality from the inclination angle [theta] 2 of the Plane of rotation of magnetic head maintaining part 11b with inclination angle from the Plane of rotation of magnetic head maintaining part 11d, thus constitute bottom surface 11e when multihead is installed to magnetic head 4L, the distance that 4R ends is different.In addition, on housing 12, be provided with and push the mechanism (not shown) of maintenance being located at magnetic head seat 5 on the guide part.

In addition, the fixing multihead of two magnetic heads shown in Figure 34 with the reference field of magnetic head seat 5 under state be arranged on the front and grind on the guide part 11a of seat 11.At this moment, the distance till making from the bottom surface to magnetic head 4L than from the bottom surface to the distance between magnetic head 4R.In addition, constituting makes the top of two magnetic heads 4 stretch out from the cylinder periphery with same degree, to make lapping apparatus be that turning axle is rotated by just changeing, reversing with cylinder center's line to magnetic head front grinding device under this state, make simultaneously sand belt approaching with the cylinder periphery, make magnetic head 4 and sand belt scan track to contact and carry out the front and grind.

Now the scan track of magnetic head 4 on sand belt described.Fig. 5, Fig. 6 represent that magnetic head front grinding device makes respectively that lapping apparatus just changes, the magnetic head when reversing scans track.Fig. 5 represents just to change, track when Fig. 6 represents to reverse.When just changeing, as shown in Figure 5, magnetic head 4R than magnetic head 4L in advance, the wide overall with that becomes magnetic head 4R of the new contact of magnetic head 4R, the new contact of another magnetic head 4L is wide to be accounted for one one and become L1 by magnetic head 4R in advance.Under this state, because R1＞L1, the amount of grinding of magnetic head 4R is many, and the amount of grinding of magnetic head 4L is few.As shown in Figure 6, when counter-rotating, because magnetic head 4L in advance, the wide L2 of new contact of magnetic head 4L is big, and the wide R2 of new contact of magnetic head 4R is little, and the amount of grinding of magnetic head 4L is many.Owing to show the identical time greatly and carry out forward and backward, final amount of grinding relatively become L1+L2 and R1+R2.As shown in scheming obviously, for:

L1+L2＞R1+R2

The amount of grinding of magnetic head 4L is many, and the amount of grinding of magnetic head 4R is few.

And then, multihead is arranged on the guide part 11b, the amount of grinding of amount of grinding multihead 4L that becomes the magnetic head 4R that makes this is few.

Like this, carry out the front when grinding to two magnetic heads 4 being installed in multihead on the magnetic head seat 5, by measuring the primary clearance degree of depth, calculating amount of grinding, corresponding therewith until the desired value gap depth, the selected guide part that multihead is installed can grind finishing with the front and go out the desired value gap depth.

In addition, more than a multihead that is installed on the lapping apparatus is illustrated, yet, also can implement a plurality of multiheads are installed on the lapping apparatus, once carry out large-duty method of grinding previously.In addition, two kinds of inclination situations to guide part are illustrated, yet, also can make the rake of guide part at 4 places different, carry out more the front of high-freedom degree and grind.

Claims (7)

1. magnetic head front grinding device, lapping magnetic heads (4) is installed on the cylindric lapping apparatus, described lapping apparatus is installed on the turntable that can just change and reverse, makes the rotation of described lapping apparatus and move so that the front of magnetic head (4) is ground relative to sand belt (7)

It is characterized in that, described lapping apparatus (1f) in the above is provided with the rotating center section (1b) that upside-down mounting is used, on bottom surface (1e), be provided with simultaneously the rotating center section (1b) that formal dress is used, the concentric setting of rotating center section (1b) that the rotating center section that described upside-down mounting is used (1b) and described formal dress are used

Described turntable (6) have with described above the turning axle of described rotating center section (1b) intercalation of (1f) or described bottom surface (1e),

And set for from described lapping apparatus bottom surface (1e) to the distance (H1) of described magnetic head (4) with above described lapping apparatus (1f) extremely the distance (H2) of described magnetic head (4) is identical.

2. magnetic head front grinding device according to claim 1, it is characterized in that, described lapping apparatus grinds seat (1) by cylindric front, housing (2), and clamping ring (3) constitutes, described cylindric front is ground seat (1) and can be rotated down at the state that the magnetic head (4) that will be fixed on the magnetic head seat (5) remains on the guide part (1a), described housing (2) is outer to be inserted in described front and grinds seat (1) and go up and magnetic head seat (5) is pushed on described guide part (1a), and described clamping ring (3) arrives at magnetic head (4) on the assigned position of described guide part (1a) housing (2) is clamped.

3. magnetic head front grinding device according to claim 2, it is characterized in that, described front grinding seat (1) is formed by the bottom of large diameter top and minor diameter, and the maximum outside diameter that constitutes described housing (2) is identical with the external diameter of described large-diameter portion, outside with described housing (2), be inserted in described front when grinding on the minor diameter of seat, it is identical with the external diameter of described housing (2) that seat is ground in described front, is the lapping apparatus of integrated outward appearance.

4. magnetic head front grinding device according to claim 3 is characterized in that, under the state that clamps with described clamping ring (3), top (1f) that seat is ground in described front and described housing (2) top becomes same plane.

5. magnetic head front grinding device according to claim 4 is characterized in that, on (1f) and the bottom surface (1e) a plurality of concentric rotation drive holes (1c) is set respectively on seat (1) is ground in described front.

6. magnetic head front Ginding process, be installed on the lapping apparatus (1) at the multihead that will grind (4), make lapping apparatus (1) rotation and relatively sand belt (7) move when carrying out the front grinding of described multihead (4), it is characterized in that, described multihead (4) is installed on the distance of setting for from bottom surface (1e) to this multihead (4) (H1) and the equidistant lapping apparatus (1) from top (1f) to this multihead (4), make this lapping apparatus (1) rotation then and move to carry out the front grinding of described multihead (4) relative to described sand belt (7), and the gap depth that compares each magnetic head, then in grinding with lapping apparatus (1) upside-down mounting, make its rotation and mobile to carry out described grinding with respect to sand belt (7), in process of lapping, become the formal dress state to carry out forward and reverse the relative front grinding device of lapping apparatus (1), and then become the upside-down mounting state to carry out forward and reverse again.

7. magnetic head front Ginding process according to claim 6 is characterized in that, the rotational time of the lapping apparatus of formal dress state (1) equates that with the rotational time of upside-down mounting state the just commentaries on classics time of each state and reversing time are by measuring the gap depth decision.

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