JPH07262541A - Actuator arm assembly - Google Patents

Abstract

PURPOSE:To obtain the actuator arm assembly with good connection workability between a wiring pattern formed on a suspension and an FPC. CONSTITUTION:The actuator arm assembly includes an actuator arm 20 fitted rotatably to a base and a suspension unit 30 fixed to a tip of the actuator arm. The suspension unit 30 has an upper suspension 22a and a lower suspension 22b formed integrally with the upper suspension 22a. The upper suspension 22a supports a 1st magnetic head 24 at its tip and has a 1st wiring pattern 34 connected with the 1st magnetic head. The lower suspension 22b supporting 2nd magnetic head 24 at its tip has a 2nd wiring pattern connected with the 2nd magnetic head. The actuator arm assembly is moreover includes a flexible printed wiring sheet 40 connected with its one end part to the 1st and 2nd wiring patterns. Further by integrally forming these upper and lower suspensions, the workability of wiring connection is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an actuator arm assembly for a magnetic disk drive, and more particularly to a suspension structure for supporting a magnetic head.

In recent years, magnetic disk devices, which are a type of external storage device for computers, have become smaller and thinner, and there is a demand for lower power consumption. In addition, it is required to improve the recording density of the magnetic disk to increase the capacity.
The number of disks mounted on the device is increasing.

[0003]

2. Description of the Related Art In a magnetic disk device for a computer,
The contact start stop (CSS) method is generally adopted for the relationship between the head and the disk. In this system, while the magnetic disk is rotating, the head floats above the disk with a small gap by the balance between the levitation force of the air fluid generated by high-speed rotation and the pressing force of the suspension that presses the head against the disk.

When the rotation of the disk is stopped, the head moves to a contactable area on the disk, where the head and the disk come into contact with each other. The head and the disk remain in contact with each other while the disk stops rotating.

Conventionally, a write signal is supplied to a magnetic head,
Alternatively, a lead wire attached to the suspension has been used to extract a read signal from the magnetic head.

However, as the magnetic disk apparatus is downsized, the structure of the suspension is changed from the type in which the lead wire is attached to the suspension with a wiring pattern as shown in FIG.

Referring to FIG. 10, an upper suspension 3a and a lower suspension 3b are caulked and fixed to the tip of an actuator arm 1. The bent portion 5a of the upper suspension 3a is adhered to the tip end side surface of the actuator arm 1, and the bent portion 5b of the lower suspension 3b is also adhered to the tip end side surface of the actuator arm 1.

A magnetic head 7 is mounted on the tip of the upper suspension 3a, and a magnetic head 7 is also mounted on the tip of the lower suspension 3b. A wiring pattern 9a, one end of which is connected to the magnetic head 7, is formed on the upper suspension 3a.
The other end of a extends to the bent portion 5a and a plurality of pads 11
connected to a.

Similarly, a wiring pattern whose one end is connected to the magnetic head 7 is also formed on the lower suspension 3b, and the other end of the wiring pattern is connected to a plurality of pads 11b formed on the bent portion 5b. There is.

A plurality of pads 15 formed at one end of a flexible printed wiring sheet (FPC) are connected to these pads 11a and 11b. The other end of the FPC is connected to an electronic circuit of a magnetic disk device (not shown).

[0011]

In the conventional suspension with a wiring pattern as described above, the upper suspension 3a and the lower suspension 3b are separately manufactured and fixed to the tip end of the actuator arm 1 by caulking. Pad 11a of upper suspension 3a
Then, the pad 11b of the lower suspension 3b is not aligned with each other, and a positional deviation G in the height direction may occur between them.

When such a position shift occurs, the FPC
Since the pad 15 of No. 13 and the pads 11a and 11b of the suspensions 3a and 3b cannot be completely joined, the pad 1
A correction work for aligning the 1a and the pad 11b is required, and there is a problem that the assemblability of the actuator arm assembly is poor.

The wiring pattern suspension is
Since the conductor is formed into a thin film pattern on the suspension, it is necessary to improve the reliability of the suspension against environmental changes such as temperature and humidity and vibration.

Accordingly, it is an object of the present invention to provide an actuator arm assembly having a wiring pattern suspension with improved reliability. Another object of the present invention is to provide an actuator arm assembly having a suspension with a wiring pattern which has an improved assembling property.

[0015]

In order to solve the above-mentioned problems, the present invention is an actuator arm assembly comprising: a base; an actuator arm rotatably attached to the base; a tip of the actuator arm. A lower suspension integrally formed with the upper suspension, the upper suspension supporting the first magnetic head at a tip portion thereof and being connected to the first magnetic head. A suspension unit having a first wiring pattern, the lower suspension supporting a second magnetic head at a tip portion thereof and having a second wiring pattern connected to the second magnetic head; Having a flexible printed wiring sheet connected at one end To provide an actuator arm assembly to symptoms.

The connecting portion is bent substantially at right angles to the suspension, and the length of the connecting portion is equal to the height of the tip end portion of the actuator arm and the sum of the thicknesses of the two spacers used for caulking.

Preferably, the wiring pattern has a lower insulating layer formed on a metallic suspension having elasticity, a lower barrier layer formed on the lower insulating layer, and a conductor layer formed on the lower barrier layer. It has an upper barrier layer formed on the conductor layer and an upper insulating layer formed on the upper barrier layer.

[0018]

According to the present invention, since the upper suspension and the lower suspension are integrally formed as a suspension unit, the pads of the upper suspension and the pads of the lower suspension are always aligned at the joint with the FPC without any positional deviation. Therefore, the workability of connecting the pad on the suspension side and the pad of the FPC can be significantly improved.

Further, since the wiring pattern has the laminated structure as described above, the reliability of the wiring pattern can be improved against environmental changes such as temperature and humidity and vibration.

[0020]

Embodiments of the present invention will now be described in detail with reference to the drawings. Referring to FIG. 1, there is shown a perspective view of a magnetic disk device to which the present invention can be applied. Reference numeral 2 indicates a housing (enclosure) including a base 4 and a cover 6. A spindle hub 8 which is rotationally driven by an inner hub motor (not shown) is provided on the base 4.

Magnetic disks 10 and spacers (not shown) are alternately inserted into the spindle hub 8, and a plurality of magnetic disks 10 are attached to the spindle hub 8 with a predetermined space therebetween.

Reference numeral 12 indicates a rotary actuator assembly composed of an actuator arm assembly 14 and a magnetic circuit 16. The actuator arm assembly 14 is a shaft 1 fixed to a base 4.
It includes an actuator block 18 which is rotatably mounted about bearings 5 around a bearing. The actuator block 18 includes a plurality of actuator arms 20.
Are integrally formed.

A base end of a suspension 22 for supporting a magnetic head 24 is fixed to the tip of each actuator arm 20. An annular packing assembly 26 is provided on the outer peripheral portion of the base 4, and the inside of the magnetic disk device is sealed by fastening the cover 6 to the base 4 with the annular packing assembly 26 interposed therebetween.

Referring to FIG. 2, there is shown a schematic perspective view of the actuator arm assembly of the present invention. An upper suspension 22a and a lower suspension 22b are caulked and fixed to the tip portion 20a of the actuator arm 20 from above and below, respectively.

The upper suspension 22a and the lower suspension 22b are integrally formed as a suspension unit 30 connected by a bent connecting portion 32. FIG. 3 shows a development view of the suspension unit 30.

The suspension unit 30 is manufactured as follows. First, a plurality of wiring patterns are patterned on a stainless steel plate. Then, it is punched into the shape shown in FIG.
Bend as shown in.

The connecting portion 32 is bent at a right angle to the upper suspension 22a and the lower suspension 22b, and the tip portion 20 of the actuator arm 20 is bent.
It is adhesively fixed to the side surface of a. The upper and lower suspensions 22a and 22b are made of elastic metal such as stainless steel.

A magnetic head 24 for reading / writing data from / to a magnetic disk is mounted on the tip of the upper suspension 22a, and similarly, a magnetic head 24 is mounted on the tip of the lower suspension 22b.

A wiring pattern 34, one end of which is connected to the magnetic head 24, is formed on the upper suspension 22a, and the other end 34a of the wiring pattern 34 is connected to the connecting portion 3.
It extends to 2 and is connected to a plurality of conductor pads.

Similarly, on the lower suspension 22b, one end of the wiring pattern 3 is connected to the magnetic head 24.
6 is formed, and the other end 36a of the wiring pattern extends to the connecting portion 32 and is connected to the plurality of conductor pads.

In this embodiment, the upper suspension 22a
Since the lower suspension 22b and the lower suspension 22b are integrally formed as a suspension unit 30, the conductor pad of the upper suspension 22a and the lower suspension 22b are formed.
The conductor pads of b are formed in alignment and do not cause misalignment with each other.

The upper suspension 22a and the lower suspension 22b are spot welded to the spacers 38, respectively, and these spacers 38 are attached to the actuator arm 20.
Is caulked from above and below to the tip portion 20a.

The length of the bent connecting portion 32 connecting the upper and lower suspensions 22a and 22b is equal to the sum of the height of the tip portion 20a of the actuator arm 20 and the thickness of the pair of spacers 38. The connecting portion 32 is fixed to the side surface of the tip portion 20a of the actuator arm 20 with an adhesive.

Flexible printed wiring sheet (FP
C) 40 is adhered to the side surface of the actuator arm 20, and the plurality of conductor pads 40a formed at one end of the FPC 40 are joined to the conductor pads of the wiring pattern formed on the upper and lower suspensions 22a and 22b. This joining is performed by, for example, soldering. The other end of the FPC 40 is connected to an electronic circuit of a magnetic disk device (not shown).

In this embodiment, the upper suspension 22a
The conductor pad of the FPC 40 and the conductor pad of the lower suspension 22b are always aligned with each other.
The connection workability with 0a is greatly improved.

FIG. 4A is a sectional view taken along the line AA of FIG. The wiring pattern 34 includes two signal lines 42 and two ground lines 44. The pair of signal lines 42 and the ground line 44 are used for writing data, and the other pair of signal lines 42 and the ground line 44 are used for reading data.

Each signal line 42 and each ground line 44 is formed by laminating a conductor layer 48 on a lower insulating layer 46 and covering it with an upper insulating layer 50. Each signal line 42 and each ground line 44
A conductor shield 52 is provided between the lines 42 to electromagnetically shield the lines 42 and 44.

FIG. 4B shows an embodiment in which the electromagnetic shield property is further improved. The bridge 54 is used to form each conductive shield 5
2 is connected. With this structure, each signal line 42 and the ground line 44 are electromagnetically sufficiently shielded from the adjacent signal line 42 or ground line 44.

Next, the structure of the signal line 42 will be described with reference to FIG. The structure of the ground line 44 is similar to that of the signal line. A lower insulating layer 46 formed by spin coating of, for example, polyimide is laminated on the upper suspension 22a formed of stainless steel, phosphor bronze, or the like.

The thickness of the upper suspension 22a is 10 to 10.
70 μm, preferably 20-40 μm, and the thickness of the lower insulating layer 46 is 0.5-20 μm, preferably 1-10.
μm.

A lower barrier layer 56 made of, for example, Cr is laminated on the lower insulating layer 46 by, for example, sputtering. The lower barrier layer 56 is made of A instead of Cr.
It can be formed from 1, Ti, Ni, Zr, W, Ta, Pd or the like. The thickness of the lower barrier layer 56 is 100 to 1000.
Å, preferably 300 to 700 Å.

A conductor layer 48 is laminated on the lower barrier layer 56. The conductor layer 48 is preferably formed of Cu, but Al, Ag, W, Ta or the like can also be used. The conductor layer 48 has a thickness of 1 to 10 μm, preferably 2 to 8 μm. The lower barrier layer 56 is provided to suppress migration of the conductor layer 48. The conductor layer 48 is formed into a predetermined pattern by etching Cu after sputtering.

A first layer made of Ti is formed on the conductor layer 48.
An upper barrier layer 58 is deposited by vapor deposition, and Au is deposited thereon.
The second upper barrier layer 60 formed of is deposited by vapor deposition. The thickness of the first upper barrier layer 58 is 100Å to 1 μm.
m, preferably 100-500Å, and the thickness of the second upper barrier layer 60 is 0.1-5 μm, preferably 0.5-
It is 3 μm.

The first upper barrier layer 58 includes the conductor layer 48 and the second upper barrier layer 58.
It is provided to improve the adhesion to the upper barrier layer 60.
The first and second upper barrier layers 58 and 60 suppress the migration of the conductor layer 48.

As the first upper barrier layer 58, Cr, Al, Ni, Zr, Ta, Pd or the like can be adopted in addition to Ti, and as the second upper barrier layer 60, in addition to Au,
Cr, Al, Ti, Ni, Zr, W, Pd, etc. can be adopted.

On the second upper barrier layer 60, an upper insulating layer 50 made of, for example, polyimide is laminated. The thickness of the upper insulating layer 50 is 0.5 to 20 μm, preferably 1
10 to 10 μm. The upper insulating layer 50 is laminated by vapor deposition.

Since the wiring pattern of this embodiment has such a multilayer structure, migration of the conductor layer 48 can be suppressed and the reliability of the wiring pattern can be improved. Since polyimide generates gas and has a hygroscopic property, it is easy to corrode Cu. Therefore, barrier layers 56, 58, 60 are required to prevent corrosion of the conductor layer 48.

Preferably, the lower insulating layer 46 is made of ionic bond type polyimide and the upper insulating layer 50 is made of ester bond type polyimide. Thus, the upper insulating layer 5
By forming 0 from the ester bond type polyimide, the reaction between the Cu conductor layer 48 and the polyimide insulating layer 50 can be suppressed.

Next, an embodiment in which the reliability of the suspension against vibration is improved will be described with reference to FIGS. FIG. 6 shows a curved portion 62 on the surface of the suspension 22a.
An insulating coating 64 is formed on the surface.

The curved portion 62 is provided to give the suspension 22a a spring property, and by forming an insulating coating 64 on this portion, it is possible to prevent the spring from sagging and to improve the vibration characteristics of the suspension. Can be improved.

FIG. 7 shows an embodiment in which an insulating coating 66 is formed on the entire surface of the suspension 22a, and similarly the vibration characteristics of the suspension can be improved. FIG. 8 shows an embodiment in which an insulating coating 68 is formed on the curved portion 62 on the back surface of the suspension 22a, and similarly, the vibration characteristics of the suspension can be improved.

FIG. 9 shows an embodiment in which an insulating coating 70 is formed on the entire back surface of the suspension 22a, and similarly the vibration characteristics of the suspension can be improved.

[0053]

According to the present invention, since the upper suspension and the lower suspension are integrally formed as a unit, the workability of connecting the conductor pad of the suspension and the FPC can be improved. In addition, since the wiring pattern has a multi-layer structure including the barrier layer, migration of the conductor layer can be prevented, and the reliability of the wiring pattern can be improved.

Furthermore, by providing the conductor shield between each signal line and the ground line, the noise resistance of the conductor pattern can be improved. Further, by partially or entirely covering the front surface or the back surface of the suspension with insulation, it is possible to prevent the fatigue of the spring and improve the vibration characteristics of the suspension.

Further, by utilizing the bent connecting portion of the suspension unit for the positioning at the time of caulking and fixing, it is possible to prevent the position variation between the upper and lower heads and the rotation.
The head positioning accuracy can be improved. further,
The upper suspension and the lower suspension can be manufactured collectively as a suspension unit, and can be swaged and fixed to the actuator arm at a time, so that the number of manufacturing steps can be reduced by half.

[Brief description of drawings]

FIG. 1 is a perspective view of a magnetic disk device to which the present invention can be applied.

FIG. 2 is a schematic perspective view of an actuator arm assembly according to an embodiment of the present invention.

FIG. 3 is a development view of a suspension unit.

4 is a cross-sectional view taken along the line AA of FIG.

FIG. 5 is an enlarged cross-sectional view of a signal line.

FIG. 6 is an example in which an insulating coating is formed on the curved portion of the suspension surface.

FIG. 7 shows an example in which an insulating coating is formed on the entire surface of the suspension.

FIG. 8 is an example in which an insulating coating is formed on the curved portion on the back surface of the suspension.

FIG. 9 shows an example in which an insulating coating is formed on the entire back surface of the suspension.

FIG. 10 is a schematic perspective view of a conventional actuator arm assembly.

[Explanation of symbols]

 20 Actuator Arm 22a Upper Suspension 22b Lower Suspension 24 Magnetic Head 30 Suspension Unit 32 Connection Part 34 Wiring Pattern 40 FPC 62 Curved Part 64, 66, 68, 70 Insulation Coating

Claims (12)

[Claims] 1. An actuator arm assembly, comprising: a base (4); an actuator arm (20) rotatably attached to the base; an upper suspension (22a) fixed to the tip of the actuator arm. And a lower suspension (22b) integrally formed with the upper suspension, the upper suspension (22b)
a) has a first wiring pattern (34) which supports the first magnetic head (24) at the tip and is connected to the first magnetic head, and the lower suspension (22b) has a second magnetic pattern at the tip. An actuator arm assembly comprising: a suspension unit (30) supporting a head (24) and having a second wiring pattern connected to the second magnetic head. 2. The actuator arm assembly according to claim 1, further comprising a flexible printed wiring sheet (40) connected to the first and second wiring patterns at one end. 3. The upper suspension (22a) and the lower suspension (22b) are integrally connected to each suspension by a connecting portion (32) which is bent at a substantially right angle, and the connecting portion (32) is The flexible printed wiring sheet is arranged on a side surface of a tip portion (20a) of the actuator arm (20), and the flexible printed wiring sheet is connected to the first and second wiring patterns by the connecting portion (32). 2. The actuator arm assembly according to 2. 4. The upper suspension (22a) is fixed to the tip end portion (20a) of the actuator arm (20) through a first spacer (38), and the lower suspension (22b).
Is the actuator arm through the second spacer (38)
It is fixed to the tip part (20a) of (20), and the connecting part (32)
4. The actuator arm assembly according to claim 3, wherein the length of the actuator arm is approximately equal to the height of the side surface of the actuator arm (20) and the thickness of the first and second spacers (38). 5. The suspension unit (30) is formed of a metal plate having a spring property,
And each of the second wiring patterns has at least one signal line
(42) and at least one ground wire (44), each of the signal wire (42) and the ground wire (44) includes a lower insulating layer (46) formed on the metal plate. , The lower insulating layer (4
6) a lower barrier layer (56) formed on the lower barrier layer
(56) a conductor layer (48) formed on the conductor layer (48), an upper barrier layer (60) formed on the conductor layer (48), and an upper insulating layer (60) formed on the upper barrier layer (60). 50. The actuator arm assembly of claim 1 including 50). 6. The lower insulating layer (46) is formed of polyimide, the lower barrier layer (56) is formed of chrome, the conductor layer (48) is formed of copper, and the upper barrier layer (60). 6. The actuator arm assembly of claim 5, wherein is made of gold and the upper insulating layer (50) is made of polyimide. 7. The conductor layer (48) and the upper barrier layer (60)
And a second upper barrier layer (5
8. The actuator arm assembly according to claim 6, wherein 8) is interposed. 8. The actuator arm assembly according to claim 5, wherein a conductive shield (52) is interposed between the signal line (42) and the ground line (44). 9. The upper suspension (22a) and the lower suspension (22b) each have a curved portion (62) for imparting springiness to the suspension, and an insulating coating (64) is provided on the surface of the curved portion (62). ) Is formed, the actuator arm assembly according to claim 1. 10. The upper suspension (22a) and the lower suspension (22b) each have a curved portion (62) that imparts springiness to the suspension, and the curved portion (62).
The actuator arm assembly according to claim 1, wherein an insulating coating (68) is formed on a back surface of the actuator arm assembly. 11. The actuator arm assembly according to claim 1, wherein an insulating coating (66) is formed on the entire surface of the upper suspension (22a) and the entire surface of the lower suspension (22b). 12. The actuator arm assembly according to claim 1, wherein an insulating coating (70) is formed on the entire back surface of the upper suspension (22a) and the entire back surface of the lower suspension (22b).