JPH06259907A - Method for assembling magnetic disk device - Google Patents

Abstract

PURPOSE:To improve the productivity and reliability of the magnetic disk device by preventing arm crack by swaging in fastening of the magnetic head assembly of the magnetic disk device. CONSTITUTION:The magnetic head assembly constituted of a spacer 1, a boss 2, a load beam 3, a magnetic head 4 and a carriage arm 6 is fastened by positioning the boss 2 provided at the spacer 1 into a hole 15 provided at the carriage arm 6 and fixing the boss 2 into this hole 15 which is expanded and plastically deformed by a swaging ball. After the head assembly is thereby temporarily fixed, at least either of the load beam 3 and the boss 2 and the carriage arm 6 are normally fixed by an adhesive.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for assembling a magnetic disk device, and more particularly to a technique effectively applied to a technique for fixing a magnetic head in a magnetic head support mechanism.

[0002]

2. Description of the Related Art For example, a magnetic head supporting mechanism in a conventional magnetic disk device has the following structure.

First, a magnetic head assembly is constituted by a magnetic head, a load beam, and a spacer. The magnetic head is bonded and fixed to the load beam and the spacer is spot-welded to the load beam.

Further, a spacer of the magnetic head assembly is screwed to the tip of the carriage arm, a swage ball or the like is passed through a hole of the carriage arm, and the boss is plastically deformed to be fixed in the hole. The magnetic head slider is supported on the surface of the magnetic disk by fastening by welding or the like.

With the above structure, the head slider is positioned at an arbitrary radial position of the magnetic disk to record information,
Or play it.

As a conventional technique for fastening a wedge, US Pat. No. 4,870,525 can be mentioned.

[0007]

However, in the method of screw fastening as in the above-mentioned prior art, when an integrated carriage effective for achieving the weight reduction and the high rigidity of the carriage is adopted, the space between the carriage arms is increased. There is a problem that the operation of inserting the screw is difficult and the assembling work is difficult.

Further, the method by welding has a problem that thermal deformation of parts occurs, pretreatment of the arm surface is required for welding, and the cost becomes high, and there are still few practical examples.

Further, the welding method requires a curing time for the adhesive, which is a problem in increasing productivity in mass production.

Particularly, in the above-mentioned integral carriage,
It is a problem in achieving high-density packaging that the following points must be solved between the narrow arms.

That is, a jig having a complicated structure and a high workability are required for the positioning work of the carriage and the magnetic head assembly and the adhesive application work, and the adhesive work is required for the replacement work of the magnetic head assembly. The difficulty of removing and cleaning the residue is a problem in achieving high-density packaging.

On the other hand, the swage fastening method is an effective method for improving the mounting density and assembling property.

In this swage fastening, the inner diameter surface of the cylindrical boss provided on the spacer is widened by penetrating a swage ball, and the outer surface of the boss is pressed against the cylindrical surface of the hole of the carriage arm. This is a method of fixing a solid body to a carriage arm.

However, in the above method, since the boss and the hole are plastically deformed, the fixing by the plastic deformation is accompanied by the stress relaxation due to the change with time. Therefore, the fastening force between the magnetic head assembly and the carriage has a value in consideration of the stress relaxation. There is a problem that the initial value must be secured.

Further, when the fastening force is increased in order to secure a margin for stress relaxation, the amount of plastic deformation that occurs in the arm becomes large, and when the elongation of the arm material is not sufficiently secured, the arm is cracked. There is also a problem that the arm is cracked.

Therefore, an object of the present invention is to assemble a magnetic disk device which facilitates the positioning work, the fastening work, and the magnetic head assembly replacement work of the carriage and the magnetic head assembly, thereby improving the productivity in mass production. To provide a method.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0018]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, according to the method of assembling the magnetic disk device of the present invention, the magnetic head and the spacer are fixed to both ends of the load beam to form a magnetic head assembly, and the magnetic head assembly is formed by the spacer into the carriage arm. A method for assembling a magnetic disk device, wherein a boss provided on a spacer of a magnetic head assembly is positioned in a hole provided on a carriage arm, and the boss is expanded and plastically deformed by a swage ball or a swage bar. It consists of a first step of temporarily fixing the magnetic head assembly to the carriage arm by fixing it in the hole, and a second step of permanently fixing at least one of the load beam and the boss and the carriage arm with an adhesive. It is a thing.

[0020]

The following effects can be obtained by the method of fastening the magnetic head assembly and the carriage arm by the above means.

In temporary fixing with a swage, the inner diameter of the boss is D _in , the outer diameter of the boss is D _out , and the swage ball diameter is D.
_{Let b} .

At this time, if D _b > D _in , then the boss outer shape D _out ′ after the swage ball is passed through the inner diameter of the boss.
Can be calculated by the following equation (1).

D _out ′ = √ (D _out ² −D _in ² + D _b ² ) ... (1) In the equation (1), the following (i) and (ii) are assumed.

(I) The volume of the boss is constant before and after passing through the wedge ball.

(Ii) Boss inner diameter D after penetration of the swage ball
_in ′ is equal to the swage ball diameter D _b (D _in ′ = D
_b ) It shall be.

D _out ′ in the equation (1) is the outer diameter of the boss after the swage ball has passed through when the swage ball is passed through the boss due to the absence of holes in the carriage arm.

That is, the boss is plastically deformed after the ball has penetrated, and the outer diameter of the boss after the ball has penetrated can be expanded to D _out ′.

Here, the hole diameter of the carriage arm is D
_{If arm} , the tightening margin δ due to the swage is δ =
D _out'- D _arm . D so that the tightening margin δ> 0
_arm, D _b, D _in, by choosing D _out, it is possible to conclude a magnetic head assembly and the carriage arm.

At this time, the fastening force can be increased by increasing the tightening margin δ.

However, by increasing the tightening margin δ, the plastic deformation amount of the carriage arm increases.

Therefore, when the breaking strain amount of the carriage arm material is small, the elongation margin of the material is lost, and the carriage arm is cracked by the wedge, and the arm is cracked.

Therefore, by setting the tightening margin δ as close to zero as possible, the occurrence of arm cracks is prevented.

However, the tightening force between the magnetic head assembly and the carriage arm is reduced by reducing the tightening margin. This requires taking measures to increase the fastening force in consideration of the reduction in fastening force due to stress relaxation due to aging.

Therefore, after the magnetic head assembly is temporarily fixed to the carriage arm by the above-mentioned swedge, an adhesive is applied to the boss and the boss and the hole are fixed by adhesion.
Increase the fastening force.

As a result, it is possible to prevent the arm from cracking due to the swage and to realize the fastening with a sufficient margin of the fastening force.

At this time, since the adhesive is applied and cured after the temporary fixing by the swage, the following effects can be obtained.

Since the adhesive application and curing work can be performed by removing the adhesive from the magnetic head positioning jig, it is possible to prevent the jig from being accidentally adhered to the magnetic head assembly or the jig to the carriage due to the flow of the adhesive. Since the magnetic head positioning jig can be used for assembling the next carriage during curing, it is possible to improve the rotation efficiency of the jig.

Furthermore, by applying an adhesive to the boss and hardening it after temporary fixing with a swage, the effect of facilitating the work of exchanging the magnetic head assembly can be obtained.

That is, since the spacer and the carriage arm are in close contact with each other by the temporary fixing, the flow of the adhesive agent between the spacer and the carriage arm can be suppressed to the necessary minimum.

Therefore, in the magnetic head assembly replacement work, it is not necessary to remove the adhesive remaining on the arm after the magnetic head assembly is peeled off, and a new magnetic head assembly can be positioned and fastened as it is. There are two methods to remove the adhesive remaining on the arm: mechanically scraping it off and removing it with a solvent.Both of these methods may cause dust to be generated by the removal work. It becomes an important point of caution. According to the present invention, these problems can be solved.

[0041]

【Example】

(Embodiment 1) FIG. 1 is a sectional view showing a magnetic head assembly of the present embodiment, FIG. 2 is a configuration diagram showing an example of a magnetic disk device to which an assembling method according to an embodiment of the present invention is applied, and FIG. 4 is a schematic explanatory view showing an example of the operation of the assembling method of the present embodiment, FIG.
FIG. 5 is a plan view showing an example of the operation of the assembling method of this embodiment.
9A and 9B are schematic explanatory views showing a method of exchanging the magnetic head assembly in the present embodiment, and FIG. 9 is a diagram showing measurement data of fastening force of the assembly of the present embodiment.

First, the configuration of the magnetic disk drive of this embodiment will be described with reference to FIG.

The spacer 1 is spot-welded to the load beam 3 and the magnetic head 4 is bonded to the load beam 3 to form a magnetic head assembly. The magnetic head assembly is fastened to the carriage arm 6 of the carriage 5, the coil 7 and the bearing 8 are attached to the carriage 5, and the circuit board 9 is further attached to form a head actuator. The magnetic disk 10 is stacked on the spindle motor 11, and the spindle motor 11 is fixed to the base 12. A shaft 13 is provided on the base 12, and the head actuator is supported by the shaft 13.

By driving the head actuator by the magnet 14 fixed to the base 12 and the coil 7, the magnetic head 4 is positioned at an arbitrary radial position of the magnetic disk 10 rotated by the spindle motor 11. Record or play back information.

The carriage 5 is provided with a plurality of carriage arms 6 and is integrally formed by die casting.

In the magnetic disk having the above structure, as shown in FIGS. 3 and 4, the spacer 1 has a cylindrical boss 2 and the carriage arm 6 has a cylindrical hole 15.

The magnetic head assembly is positioned on the carriage arm 6 by inserting the boss 2 into the hole 15.

At this time, the magnetic head assembly is positioned in the rotational direction by hitting the end surface of the spacer, that is, the surface D in FIG. 4 with a jig.

Next, the operation of this embodiment will be described.

[0050] In this embodiment, the inner diameter of the boss 2 D _in = φ1.956mm, the outer diameter is D _{ou t} = φ2.731mm as an example.

At this time, the diameter of the swage ball 16 is set to D
_{When b} = φ2.032 mm, the outer diameter of the boss 2 after the swage ball 16 is passed through the inner diameter of the boss is D _out ′ = φ2.786 mm according to the above formula (1).

At this time, the direction of penetrating the swage ball 16 can be either the direction A or the direction B in FIG.

Further, as shown in FIG. 1, the UP head, the DOWN
With the head set on the carriage arm 6, the swage ball 16 is passed through to make the UP and DO
It is also possible to swage WN at the same time.

Further, when the swage ball 16 is penetrated, it is desirable to press the surface C in FIG. 3 so that the spacer 1 does not separate from the carriage arm 6.

Here, for example, if the diameter of the hole 15 of the carriage arm 6 is D _arm = φ2.73 mm, the swage margin is δ = D _out ′ −D _arm = 56 μm, and the hole diameter D _arm = φ2.764 mm. Then tightening margin δ = 22μmm,
Hole diameter D _arm = φ2.785mm, tightening margin δ = 1μ
m.

If the diameter of the swage ball 16 is increased, the tightening margin δ is increased.

For example, let the diameter of the swage ball 16 be D
_{If b} = φ2.083 mm, from the formula (1), the outer diameter of the boss 2 after penetrating the swage ball 16 is D _out ′ = φ2.823 mm
Becomes

At this time, the hole 1 of the carriage arm 6
Assuming that the diameter of 5 is D _arm = φ2.73 mm, the tightening margin of the swage is δ = D _out ′ −D _arm = 93 μm, hole diameter D
_{When arm} = φ2.764 mm, tightening allowance δ = 59 μm, and hole diameter D _arm = φ2.785 mm, tightening allowance δ = 38
μm.

[0059] As described above, as a tightening margin _{δ> 0, D arm, D} b, by selecting D _in, and D _{ou t,} can be fastened to the magnetic head assembly and the carriage arm 6 .

The fastening force is applied to the rotational torque T of the magnetic head assembly.
When evaluated by, the rotational torque T depends on the interference δ. This relationship is shown in FIG.

For example, when the tightening margin is 93 μm, the rotating torque T = 1.0 to 1.8 kgf-cm, when the tightening margin is 38 μm, the rotating torque T = 0.6 to 1.1 kgf-cm, and when the tightening margin is 1 μm, the rotating torque T is T. = 0.1 to 0.4 kgf-cm.

The rotation torque T is required to be 0.12 kgf-cm or more as the rotation torque specification in consideration of a force caused by the head colliding with the stopper when the carriage is out of control or when the disk starts rotating. .

In order to secure a margin of fastening force, it is desirable to increase the tightening margin.

However, increasing the tightening margin increases the plastic deformation of the hole 15 of the carriage arm 6.

For example, in the above example, the hole diameter D _arm
= Φ2.73 and interference δ = 93 μm, the maximum value of hole elongation (hereinafter referred to as ε) is ε = δ / D _arm = φ3.
4%, D _arm = φ2.785, δ = 38 μm, ε =
1.3%, D _arm = φ2.785, δ = 1 μm,
ε is 0.04%.

When magnesium die casting is used as the carriage material, the elongation of the material is 3% to 7%.

Therefore, when ε = 3.4%, the elongation of the material may be exceeded and the carriage arm 6 may be cracked and the carriage arm 6 may be cracked. To prevent this, it is desirable to reduce the tightening margin δ.

In order to solve these points, in the present embodiment, the rotational torque T is increased by temporarily fixing the tightening margin to 1 μm and then performing the main fixing with the adhesive Z.

As described above, when the tightening margin δ = 1 μm, the rotation torque T = 0.1 to 0.4 kgf-cm, and the rotation torque specification of 0.12 kgf-cm or more is not satisfied.

Considering the decrease of the rotational torque due to the change with time, it is desirable to have a margin of 3 times or more with respect to the specification of 0.12 kgf-cm.

Therefore, the fastening by the swage is temporarily fixed, the fastening by the adhesive is the main fixing, and the fastening force is reinforced by applying an adhesive to the boss 2 fastened by the swage and curing it.

Fixing with an adhesive is performed as shown in FIG.
After temporarily fixing the heads of P and DOWN with a swage, by applying the adhesive Z between the bosses 2 of UP and DOWN, the adhesive Z is permeated between the holes 15 and the boss 2 to cure the adhesive Z. To fix it.

As a result, as shown in FIG. 9, the fastening force is the rotational torque T = 1.8 to 2.6 kgf-cm, and a margin of 15 times or more the above specifications can be secured.

As a result, it is possible to prevent the arm from cracking due to the swage and to secure the fastening force with a sufficient margin.

At this time, since the main fixing is performed by the adhesive application effect after the temporary fixing by the swage, the following effects can be obtained.

That is, since the work of applying the adhesive can be performed by removing the magnetic head assembly or the carriage from the magnetic head positioning jig, the jig and the magnetic head assembly or the jig and the carriage are erroneously caused by the flow of the adhesive. Can be prevented from adhering, and during the effect, the magnetic head positioning jig can be used for assembling the next carriage, so that the rotation efficiency of the jig can be improved.

Next, a method of replacing the magnetic head assembly will be described with reference to FIG.
Will be explained.

As shown in FIG. 5, the wedge 17 is inserted into the F portion between the spacer 1 and the carriage arm 6 which are fastened as described above, and the spacer 1 and the carriage arm 6 are peeled off. Is removed from the carriage arm 6.

Next, a new magnetic head assembly is positioned on the carriage arm 6 and temporarily fixed by a swage according to the same procedure as described above, and then an adhesive is applied to the boss 2.
Permeate and cure to permanently fix.

As described above, the magnetic head assembly can be replaced.

At this time, the adhesive Z is applied after the temporary fixing by the swage, and the adhesive Z is permeated between the spacer and the carriage arm to be cured, so that the main fixing is performed, and the following effects are obtained.

That is, since the spacer 1 and the carriage arm 6 are in close contact with each other by temporary fixing, the flow of the adhesive agent Z between the spacer 1 and the carriage arm 6 can be suppressed to a necessary minimum.

Therefore, in the magnetic head assembly replacement work, it is not necessary to remove the adhesive Z remaining on the carriage arm 6 after the magnetic head assembly is peeled off, and a new magnetic head assembly can be positioned and fastened as it is. . The adhesive Z remaining on the carriage arm 6 can be removed by a mechanical scraping method or a solvent method. However, both methods may cause dusting due to the removing work. Management is a problem for equipment reliability and production work safety. According to the present invention, these problems can be solved.

Therefore, according to the method of assembling the magnetic disk drive of this embodiment, when the magnetic head assembly of the magnetic disk drive is fastened, the carriage arm is prevented from being cracked by the swage and the fastening force is increased by applying the swage and the adhesive. The magnetic disk device can be made stronger and the productivity and reliability of the magnetic disk device can be improved.

(Embodiment 2) FIG. 6 is a schematic explanatory view showing a method of fixing a magnetic head assembly which is an embodiment of the present invention, and FIG. 7 is a magnetic disk having a notch in a boss which is an embodiment of the present invention. It is a schematic explanatory drawing which shows the head assembly fixing method.

Next, the structure of the magnetic head assembly of this embodiment will be described with reference to FIG.

The magnetic head assembly of this embodiment has a structure in which one of the bosses 102 of the spacers 101 and 107 of the UP or DOWN head can be inserted into the inner diameter of the other boss 108, and the other parts are the same as the embodiment. The same as 1.

Next, the operation of this embodiment will be described.

The outer boss 108 is positioned in the hole 15 of the carriage arm 6, the inner boss 102 is positioned in the inner diameter of the outer boss 108, and the swage ball 16
The magnetic head assembly is temporarily fixed to the carriage arm 6 by penetrating the inner diameter of the inner boss 102.

Thereafter, the adhesive Z is applied as shown in FIG.
It is permanently fixed by allowing it to penetrate and cure.

Therefore, according to the method of assembling the magnetic disk device of this embodiment, when the magnetic head assembly of the magnetic disk device is fastened, one boss is inserted into the inner diameter of the other boss to apply a swage and an adhesive. It is possible to prevent the carriage arm from cracking due to the swage and to strengthen the fastening force, thereby improving the productivity and reliability of the magnetic disk device.

When the adhesive Z does not sufficiently penetrate in FIG. 6 and the adhesive force between the outer boss 108 and the hole 15 is insufficient, the outer boss 108 has several cutouts as shown in FIG. By providing 118, it is possible to improve the penetration of the adhesive Z and enhance the adhesive strength.

(Embodiment 3) FIG. 8 (a) is a schematic explanatory view showing a case where a magnetic head assembly is temporarily fixed using a swage bar which is an embodiment of the present invention, (b), (c). , (D)
Is a structural example of the EE cross section of (a).

As shown in FIG. 8, the structure of the magnetic head assembly of this embodiment is the same as that of the first embodiment.

Next, the operation of this embodiment will be described.

In the first and second embodiments, the wedge ball 1 is used.
The case of temporarily fixing the magnetic head assembly to the arm 6 by widening the diameter of the boss 2 by 6 has been described. However, the temporary fixing method of the present embodiment, as shown in FIG. The boss diameter is increased by the large swage bar 219.
This is a temporary fixing method.

Therefore, according to the method of assembling the magnetic disk device of this embodiment, when the magnetic head assembly of the magnetic disk device is fastened, the swaging bar 219 strengthens the fastening force to improve the productivity of the magnetic disk device. The reliability can be improved.

At this time, as for the cross-sectional shape of the swage bar 219 of FIG. 8, if the outermost diameter is larger than the inner diameter of the boss,
It is possible to adopt any shape such as the cylindrical shape of FIG. 9B, the hexagonal prism shape of FIG. 7C, and the quadrangular prism shape of FIG.

Further, FIG. 2 shows an embodiment in which an integral carriage is formed by integrally molding a plurality of arms by die casting, but the carriage is assembled by stacking a plurality of arms or by fastening screws. It can also be applied to objects and similar effects can be obtained.

As for the adhesive application point, in addition to the above-mentioned embodiment, it is also possible to apply from the portion F of FIG.
The same effect can be obtained.

The invention made by the inventor of the present invention has been specifically described above based on the embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

[0102]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

That is, according to the method of assembling the magnetic disk device of the present invention, it is possible to prevent the carriage arm from cracking due to the wedge.

Further, the fastening force between the magnetic head assembly and the carriage arm is fixed by the main fixing by the adhesive application effect.
It is possible to secure a margin of 15 times or more with respect to the rotational torque specification, and this can secure a sufficient margin even when the fastening force is reduced due to a change over time.

Furthermore, since the adhesive application effect work can be performed by removing it from the magnetic head positioning jig,
It is possible to prevent the jig and the magnetic head assembly or the jig and the carriage from being accidentally adhered by the flow of the adhesive.

Further, since the magnetic head positioning jig can be used for assembling the next carriage during curing, it is possible to improve the rotation efficiency of the jig.

When the adhesive is applied and cured, the flow of the adhesive between the spacer and the carriage arm can be suppressed to a necessary minimum, and it remains on the arm after the magnetic head assembly is peeled off in the magnetic head assembly replacement work. There is no need to remove the adhesive.

As a result, it is possible to prevent dust generation due to the operation of removing the adhesive residue, and to prevent the risk of solvent scattering when a solvent is used for removing the residue.

As a result, it is possible to improve the control of dust generation due to the application of the adhesive to the magnetic head assembly and the productivity and reliability of the magnetic disk device.

[Brief description of drawings]

FIG. 1 is a sectional view showing a magnetic head assembly according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an example of a magnetic disk device according to an embodiment of the present invention.

FIG. 3 is a schematic explanatory view showing an example of the operation of the assembling method of the present embodiment.

FIG. 4 is a plan view showing an example of the operation of the assembling method of this embodiment.

5A and 5B are schematic explanatory views showing a method of exchanging a magnetic head assembly in this embodiment.

FIG. 6 is a schematic explanatory view showing a magnetic head assembly fixing method according to an embodiment of the present invention.

FIG. 7 is a schematic explanatory view showing a magnetic head assembly fixing method in which a boss is provided with a notch, which is an embodiment of the present invention.

FIG. 8A is a schematic explanatory view showing a case where the magnetic head assembly is temporarily fixed using a swage bar according to an embodiment of the present invention, and FIGS. 8B, 8C and 8D are It is a figure which shows an example of a structure of the EE cross section of a).

FIG. 9 is a diagram showing measurement data of fastening force of the assembly of the present embodiment.

[Explanation of symbols]

 1, 101, 107 Spacer 2, 102, 108 Boss 3 Load beam 4 Magnetic head 5 Carriage 6 Carriage arm 7 Coil 8 Bearing 9 Circuit board 10 Magnetic disk 11 Spindle motor 12 Base 13 Axis 14 Magnet 15 Hole 16 Swageball 17 Wedge 118 Notch 219 Swedge bar Z Adhesive

Claims (1)

[Claims] 1. A method of assembling a magnetic disk device, wherein a magnetic head and a spacer are fixed to both ends of a load beam to form a magnetic head assembly, and the magnetic head assembly is fixed to a carriage arm by the spacer. There, a boss provided on the spacer of the magnetic head assembly is positioned in a hole provided in the carriage arm, and the boss is expanded and plastically deformed by a swage ball or a swage bar to be fixed in the hole. Thus, it comprises a first step of temporarily fixing the magnetic head assembly to the carriage arm and a second step of permanently fixing at least one of the load beam and the boss and the carriage arm with an adhesive. And a method for assembling a magnetic disk device.