JPH03272014A - Head positioning mechanism for magnetic disk device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to magnetic disk drives, and more specifically, to an improved fixing structure of a head tube that electrically connects a head and a flexible printed wiring board. The present invention relates to a head positioning mechanism for a magnetic disk drive having a magnetic disk drive.

[Prior Art] A typical magnetic disk device is, for example, disclosed in Japanese Patent Application Laid-Open No. 1986-
It is described in No. 167489.

Among such magnetic disk drives, a head positioning mechanism having a structure as shown in FIG. 7 has already been provided.

This head positioning mechanism includes a swing arm S and a head assembly H. The main body portion of the swing arm S is attached to a shaft via a bearing, and is configured to be able to rotate on the shaft in the front-rear direction on the plane of the drawing. In the head assembly H, a funnel arm a supporting the head is attached to the free end of a funnel arm b forming part of a swing arm. The swing arm is rotated by a step motor (not shown) causing the swing arm to rotate about the axis, thereby moving the head C to a desired position on the magnetic disk d. .

Head C is an integrated circuit e for writing and reading
It is electrically connected to a flexible printed wiring board f mounted with the following. The thin wire from the head coil is inserted into the head tube g and protected. To connect, connect this tube to rod arm a and head arm b,
The tube is held by a member on the rod arm, a tape i is wrapped around the tube and the head arm, and a thin wire protruding from the end of the tube is soldered to a flexible printed wiring board f.

[Problems to be Solved by the Invention] In this head positioning mechanism, the head arm b and the tape i have different coefficients of thermal expansion.

Therefore, when the ambient temperature changes, the tape i acts to suppress the thermal deformation of the head arm b, generates a thermal stress distribution in the head arm, causes the head arm to deform in the same way as a bimetal, and causes the head C cause off-track.

In fact, when using tapes whose coefficients of linear expansion differ greatly from those of the head arm, it is necessary to strictly control the wrapping length and pasting method to ensure that there is almost no variation in this type of equipment. Required conditions, temperature 50″
It is extremely difficult to satisfy the thermal off-trace of less than 1 mμ in C. Furthermore, the adhesive applied to the tape h may have a chemical effect on the head tube d, or the gas generated may corrode the disc, and its performance may deteriorate over time and temperature changes. If the tape i is not peeled off, the reliability of the magnetic disk device may be reduced.

An object of the present invention is to enable high-precision positioning of the heel and dowel regardless of temperature changes, to further improve reliability, and to further improve workability. There is a particular thing.

[Means for Solving the Problem] In order to achieve the above object, in the magnetic disk head positioning mechanism of the present invention, the means for fixing the head tube to the head arm has substantially the same linear expansion coefficient as the head arm. The head tube is made of a material having a similar shape and is provided with a tube holding portion having the same form as the means for securing the head tube to the load arm.

[Function] When this head positioning mechanism is configured as a part of a magnetic disk drive, even if the ambient temperature changes, the members fixing the head tube will undergo thermal expansion the same amount as the head arm. Since it does not generate complicated thermal stress, head off-track does not occur. Furthermore, the fixing member can be attached to the head arm by any method, such as using an adhesive that does not affect the head tube or disc, or using only the elasticity of the member itself, so it is highly reliable. You can get a magnetic disk device.

Further, the assembly of the head tube to the load arm and the head arm in the assembly work and the removal of the head tube in the repair work can be easily performed because the work procedures are substantially the same.

[Embodiment] An embodiment of the head positioning mechanism for a magnetic disk device of the present invention will be described below with reference to FIGS. 1 to 6.

In FIGS. 1 and 2, reference numeral S indicates a swing arm, H indicates a head assembly, and F indicates a flexible printed wiring board, respectively.

The swing arm S includes a main body 10 and a head arm 11
The main body is attached to a shaft 12 via a bearing, and can rotate on the shaft. Head assembly H is load arm 1
3 and a head 14, and a load arm is supported at the free end of the head arm so as to face the two adjacent heads. The flexible printed circuit board F is mounted with an integrated circuit 16 for writing and reading, and has one end fixed to the side of the main body 10 and the other end independent of the head positioning mechanism. Fixed.

The thin wires extending from the head coil of the head assembly H are each inserted into the head tube 15 and protected. These tubes are arranged along each of the load arm 13 and head arm 11 and are fixed to these arms. Electrical connection is made by soldering the end of the thin wire protruding from the tube end to the flexible wiring board F.

As shown in FIG. 3, the fixing means 27 for the head tube 15 in the load arm 13 is formed integrally with the load arm, and is provided with a recess 28 having a narrow opening and a wide bottom. ing. The head tube 15 is fixed to the load arm 13 by fitting into the recess 28 and caulking the portion forming the recess.

The fixing means 17 of the head tube 15 on the head arm 11 consists of a member 17 in the form of a bellows clip. The fastening element itself comprises a section 21 and two sections 22, 23 arranged at its ends, as shown in FIGS. 4 and 5. The portion 21 has a shape corresponding to the cross-sectional shape of the head arm to which this fixing member is attached. Here, since the fixing member 17 is attached to the head arm 11 made of a parallel plane plate, the portion 21
has the form of a channel-shaped cross-sectional member.

Attachment to the head arm 11 is accomplished by mating the portion 21 to the head arm 11 with an adhesive. The sections 22, 23 have a plate-like form and are formed integrally with the section 21 in such a way that they each protrude from the wall surface forming the bottom of the groove of the section 21.

In the portions 22.23 there are two recesses 25.23, which have the same form as the retaining elements in the fixing element on the funnel arm.
There are 26. The recess itself, like the recess 28 of the fixing member 27, has a wide opening and a wide bottom, as best shown in FIG. The width A of the opening is smaller than the diameter of the head tube 15, the width B of the bottom is larger than the diameter of the head tube, and the depth C is smaller than the diameter of the head tube. The head tube 15 is located between the portions forming the openings in a crushed state, and is prevented from being pulled out from the fixing member 17 by making point contact with and being held by the portions forming the openings. .

Further, the fixing member itself is made of a material having substantially the same coefficient of linear expansion as the head arm 11 and the load arm 13. In this head positioning mechanism, the swing arm S has a coefficient of linear expansion α=17.3xl, for example.
Since it is made of a metal material with a stiffness of O-'(1/"C), the fixing member must be made of the same material, or another material with a similar value and similar stiffness. For example, when the material is metal, the material is punched out of a plate having the same coefficient of thermal expansion as the load arm 13, and the portions 21 and 22 and 23 are formed into a brace bottom mold.

In this head positioning mechanism, assembly of the head tube begins by attaching member 17 to head arm 11. This is done by applying adhesive to the grooves in section 21 of member 17 and allowing the adhesive to harden as it engages the sides of head arm 11, as shown in FIG.

At this time, the adhesive is, for example, Araldite XN1
It is made of a material such as No. 244 (trade name) that has a chemical effect on the head tube 15, corrodes the disk, and is resistant to changes in salinity and does not cause performance deterioration or change over time.

The head tube 15 is pushed into the recess 25 in the load arm 133 and the fixing member 17 on the head arm, and the recess 28 in the fixing member 27, and the free end is passed through the notch in the end of the flexible printed wiring board F. Connect the thin wires protruding from the edges to the flexible printed circuit board F.
It is soldered to the The head tube 15 in the paired head 14 is connected to the associated load arm 13.
and the head arms 11, and are inserted into the recesses in the members 27 and 17 on these arms and the notches in the flexible printed wiring board F, and are assembled by connecting the thin wires to the flexible printed wiring board F. It will be done. At this time, the member 27 on the head arm is fixed by pushing the head tube into another recess 26.

The assembly of the head tube is thus carried out by sliding the head tube 15 along the arm 13.11 and pushing it into the recess of the member 27.17,
Furthermore, since both members can be fixed in a tear-down procedure, it can be done quickly without the risk of damaging the head tube 15, head arm 11, or the like.

After the head tube 15 is assembled in this way, this head positioning mechanism is placed on the frame of the magnetic disk device so that the magnetic disk is positioned between the heads 14 facing each other, and the shaft 12 is attached to the frame of the magnetic disk drive. By holding it in a bearing, a magnetic disk device can be configured.

However, when the magnetic disk device is operated, even if the temperature inside the device rises, the head arm 11 and the fixing member 1
7 causes almost uniform thermal deformation, the amount of thermal expansion is the same, and the rigidity of the fixing member 17 and the head arm is large, so it is not affected by the thermal expansion of the adhesive, and it can be fixed like a conventional mechanism. Since no special thermal stress is generated between the member 17 and the head arm 11 due to the bimetal effect, operation without off-track can be performed. The adhesive that attaches the fixing member 17 to the head arm 11 should be one that has a chemical effect on the head tube 15, corrodes the disk, is resistant to temperature changes, and does not cause performance deterioration or deterioration over time. Therefore, the reliability of the magnetic disk device can be improved.

In addition, in the repair work, the head tube can be removed by unsoldering the head tube 15 and the flexible printed wiring board F, further bending the head tube 15, and removing the dents 25 and 26 of the fixing member 17 and the fixing member 27. It is done by protruding from a hollow. The head tube is reassembled after repair by fitting the head tube into the same fixing member 17 and connecting the wires. At this time, the work can be done in the same way as the work on the fixing member on the load arm, and it can be done without damaging the head tube, head arm, load arm, etc. Since there is no need to prepare any new means, it can be done extremely easily and quickly.

In the embodiment described above, the portions of the fixing member 17 on the load arm and the fixing member 27 on the head arm that hold the head tube 15 are formed of recesses 25 and 26 that are wide open and have a wide bottom shape. However, other shapes of indentations or other structures can be adopted, and the attachment of the member 27 to the head arm 11 is not limited to adhesives, but also the width of the groove of the portion 21 and the thickness of the head arm. Various other means can be adopted, such as making the part smaller than the size of the part 21 and allowing the part 21 to be attached to the head arm 11 due to its elasticity when the part is fitted into the head arm. Further, the overall shape of the fixing member 17 can also take other forms, and can be formed integrally with the head arm if necessary, and the material is not limited to metal, but other materials can also be selected. I can do it. In this case, the stiffness of the material is
When attachment to the head arm is done by adhesive, it is preferable that the adhesive has the same coefficient of thermal expansion as, or close to, that of the head arm and fixing member 17.

[Effects of the Invention] As explained above, in the head positioning mechanism for a magnetic disk drive of the present invention, the head arm is not subjected to complicated thermal stress when the ambient temperature changes, and furthermore, the control can be performed easily. This makes it possible to perform highly accurate tracking, and in addition, the attachment of the member that fixes the head tube to the head arm to the head arm does not cause corrosion of the disk, deterioration or damage to the head tube, and is free from temperature changes and aging. An adhesive that does not change easily can be used, and if necessary, the process can be performed without an adhesive, making it possible to provide a highly reliable magnetic disk device.

[Brief explanation of drawings]

1 to 6 show an embodiment of the head positioning mechanism for a magnetic disk drive of the present invention, in which FIG. 1 is a plan view, FIG. 2 is a side view of the same, and FIG. Figure 4 is an enlarged view of the area around the member that fixes the head tube on the load arm. Figure 4 is an enlarged view of the area around the member that secures the head tube on the head arm. Figure 5 is a perspective view of the same. Figure 6 is Vl-VT. It is an enlarged sectional view along the line. FIG. 7 is a plan view of a conventional head positioning mechanism for a magnetic disk device. 11...Head arm, 13...Load arm, 1
4...Head, 15...Head tube, 17...
・Fixing member on head arm, 25.26...dent, 27...fixing member on load arm, F...flexible printed wiring board, H...head assembly,
S...Swing arm.

Claims (1)

[Claims] 1. It is equipped with a head assembly, a rotatable swing arm that supports the head assembly, and a flexible printed wiring board with one end fixed to the swing arm, and the thin wire that electrically connects the head to the flexible printed wiring board is the head tube. The head tube is inserted into the head assembly, and the head tube is passed through the load arm on the head assembly and the head arm on the swing arm. The means for fixing the head tube to the load arm is made of a material having substantially the same coefficient of linear expansion as the head arm, and includes a tube holding portion having the same form as the means for fixing the head tube to the load arm. head positioning mechanism for magnetic disk drives.