JP2570103B2 - Carriage structure of magnetic disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carriage structure of a magnetic disk drive for moving and positioning a magnetic head in a magnetic disk drive, and more particularly, to a large capacity magnetic disk drive having a plurality of arms for supporting the magnetic head. The present invention relates to a carriage structure of a magnetic disk drive.

[0002]

2. Description of the Related Art FIGS. 4A and 4B are a top view and a sectional view taken along the line BB of a carriage structure of a magnetic disk drive showing an example of the prior art. Conventionally, as shown in FIG. 4, for example, a carriage structure of a magnetic disk device of this type includes a fixed shaft 5 fixed to a base (not shown) of the magnetic disk device.
And a pair of rotary bearings 6 which are fitted with the inner rings at both ends of the fixed shaft 5 and are mounted separately from each other, and an arm 1 for mounting a magnetic head (not shown) via a suspension on a side surface. Has a carriage main body 2 which is fitted on the outer race and rotates around a fixed shaft 5. The inner race of the rotary bearing 6 whose outer race is press-fitted into the carriage body 2 is precisely fitted to the fixed shaft 5 to apply a preload by a spring to eliminate play in the thrust direction.

The operation of a carriage for positioning a magnetic head for recording / reproducing is performed by applying a current to a coil of a voice coil motor (not shown) so that the main body 2 swings around a fixed shaft 6 and is attached to the arm 1. The positioned magnetic head is positioned at a desired position with respect to the surface of the corresponding magnetic disk.

In this carriage structure, by integrating the main body 2 and the plurality of arms 1, when the arm 1 is rotated and the magnetic head is positioned, the position information of any one of the arms 1 is fed back. The magnetic heads attached to all the arms 1 are uniquely positioned. This has the advantage that the moment of inertia is smaller and positioning accuracy is more easily obtained as compared with a carriage having a conventional structure in which the main body and the arm are separated and connected by bolts and nuts.

[0005]

Normally, the magnetic disk device shows different temperatures depending on the temperature inside the device and the difference in the operation time such as the start of operation or the steady state. In extreme cases, the temperature difference is several. It can be as high as ten degrees C.

FIG. 5 is an exaggerated view showing the deformation of the carriage body due to a temperature change in the apparatus. As shown in FIG. 5, the carriage main body arranged in the housing having the temperature difference has a thermal stress at a portion where the two are in contact with each other due to a difference in thermal expansion coefficient between the rotary bearing press-fitted into the main body and the main body. Then, the main body undergoes constriction deformation, and the relative positions of the respective arms derived from the main body differ. This occurs because the rotary bearing made of stainless steel has a smaller coefficient of thermal expansion than the main body made of aluminum alloy.

When the position of each arm changes in accordance with the temperature as described above, in a method of setting the position of another arm by one arm of positioning recognition, even if the reference arm is positioned, the magnetic force of the other arm is set. The position of the head deviates from the desired position, causing a so-called thermal off-track. This not only causes a recording / reproducing error but also hinders an increase in the capacity of the magnetic disk device.

One example of a carriage structure for reducing the amount of thermal off-track is disclosed in Japanese Patent Application Laid-Open No. 3-254472. In this carriage structure, the carriage main body is separated into a block including an arm and a ring portion into which the outer ring of the rotary bearing is press-fitted. The bearing is press-fitted with a gap in the structure to avoid applying thermal stress to the block. However, although this carriage structure can reduce the amount of deformation of the arm due to temperature change, the block and the ring contact the entire area between the rotary bearings, so the distribution of thermal stress is uneven due to uneven contact area etc. The relative position of the arm derived from the block may vary due to distortion, and the problem has not been completely solved.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to reduce a change in the positioning position of a magnetic head due to a change in temperature, eliminate variations in the relative positions of a plurality of magnetic heads, reduce the amount of thermal off-track, and achieve high precision. Another object of the present invention is to provide a magnetic disk drive carriage structure applicable to a high-capacity magnetic disk drive.

[0010]

SUMMARY OF THE INVENTION The present invention is characterized in that a plurality of arms holding a magnetic head for recording and reproducing information are arranged in one direction and are derived from a side surface of the carriage body.
A magnetic disk drive having a pair of rotary bearings fitted into the carriage body in a spaced apart manner in parallel with the one direction, and a fixed shaft fitted in inner rings of the pair of rotary bearings and mounted so that the carriage body can rotate. In the carriage structure, the carriage body is separated into a cylindrical member into which the outer rings of the pair of rotary bearings are fitted and a main body member having the arm, and the main body member and the cylindrical member are arranged in an axial direction including the rotary bearing. The carriage structure of the magnetic disk drive is provided with a fixing means for fixing the main body member and the cylindrical member to each other at least at one end and separated from each other by a predetermined gap.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIGS. 1A and 1B are a top view and a sectional view taken along the line AA of a carriage structure of a magnetic disk drive showing a first embodiment of the present invention. As shown in FIG. 1, the carriage structure of the magnetic disk drive has a main body 2a having a cylindrical member 3 and an arm 1 into which outer rings of a pair of rotary bearings are fitted.
The main body 2a and the cylindrical member 3 are separated from each other by a predetermined gap 7 between the pair of rotary bearings 6, and the main body 2a and the cylindrical member 3 are fixed to one end of the carriage member. 4 is fixed. The cylindrical member 3 is made of the same material as the aluminum alloy as the material of the main body 2a or a material having a similar thermal expansion coefficient, and has a smaller thickness than the main body 2a.

By providing the thin cylindrical member 3 separated from the main body 2a in this manner, for example, when the temperature of the magnetic disk drive is low, the rotary bearing 6 having a small thermal expansion coefficient is provided.
The thermal stress generated in the cylindrical member 3 is absorbed by the cylindrical member 3 itself, and the cylindrical member 3 is distorted as shown by a dotted line.
Even if the cylindrical member 3 is distorted, the cylindrical member 3 and the main body 2
Since the main body 2a is separated from the main body 2a by the gap 7, no thermal stress is applied to the main body 2a. Therefore, the main body 2a is not distorted and the relative position of each arm 1 does not change. This action is the same as providing the cylindrical member 3 with a spring member for absorbing thermal stress. Thus, the cylindrical member 3, it is desirable to reduce the cross-sectional coefficient by changing the cross-sectional shape of the central portion of or axially be to use the same aluminum alloy as the main body 2a to the smaller material modulus of elasticity.

FIG. 2 is a cross-sectional view of the carriage structure of the magnetic disk drive shown in FIG.
9 is a graph showing the amount of thermal off-track when the simulation is performed and the amount of thermal track according to the conventional structure. By the way, a prototype of a carriage having a large number of heads with 20 derived arms was manufactured and the amount of thermal off-track was measured with that of a carriage having a conventional structure. As shown in FIG. Was greatly improved. Here, H0 to H20 indicate the numbers of a plurality of magnetic heads from above to below, and HSV indicates a magnetic head having a positioning reference. This thermal track amount is an amount that occurs when the temperature is changed from 5 ° C. to 60 ° C.

FIGS. 3A and 3B respectively show the present invention.
FIG. 4 is a cross-sectional view of a part of a carriage showing the first and second embodiments of the present invention. In the explanation of the concept in the embodiment of the above-mentioned invention
The main body and the cylindrical member are fixed by press-fitting at both ends, but when the number of arms is increased and the span between the rotary bearings is increased, the reaction force F generated by thermal stress on the rotary bearing as a fulcrum is generated.
Can not be ignored and the concept of the above-mentioned embodiment
In the fixing means in the above , there is a possibility that the end of the main body may be deformed. Of course, a method of increasing the thickness to increase the strength so that the main body is not deformed even if the reaction force F is increased is conceivable. However, the weight increases due to the increase in the wall thickness, and as a result, the inertia force is increased and the precision is increased. Positioning may not be possible.

Therefore, in this embodiment, a fixing means for fixing the main body and the cylindrical member so that the reaction force does not act on the main body is made by a method other than press-fitting. As an example of this fixing means, for example, as shown in FIG. 3A, a gap C is provided between the main body 2b and the cylindrical member 3a at both ends to loosen the fitting at both ends. . Desirably, the gap C is substantially zero at low temperatures. This is to avoid contact between the main body 2b and the end of the cylindrical member 3a which is distorted in the direction in which the cylindrical member 3a expands due to the reaction force F at low temperatures. In order to prevent the cylindrical member 3a and the main body 2b from shifting in the rotating direction and to prevent the main body 2b from coming off, at least one threaded pin 13 having a pin portion inserted into the hole 8 is provided on the circumference to fix the cylindrical member 3a and the main body 2b. I do. Then, if necessary, the threaded pin 13 is prevented from being loosened by the fastening nut 9 for fixing. Alternatively, the pin may be fixed with a normal screw.

As another embodiment, as shown in FIG. 3 (b), a groove 11 is formed in the end face of the cylindrical member 3b, a fixing plate 10 is fitted in the groove 11, and a set screw is formed in the end face of the main body 2c. It is fixed. Fixing mechanisms for fixing with the fixing plate 10 are provided at both ends of the main body 2c, and the cylindrical member 3b is sandwiched and fixed, and the groove 11 on the cylindrical member 3b side is formed so as not to hinder the radial movement of the fixing plate 10 due to thermal expansion. It is formed completely across the end face. The fixing method of this embodiment has an advantage that the contact between the main body 2c and the cylindrical member 3b is reduced.

[0018]

As described above, according to the present invention, the carriage main body is separated into an inner cylindrical member into which the outer rings of the pair of rotary bearings are fitted and an outer main body member having an arm, and the main body member and the cylindrical member rotate. The bearings are separated by a predetermined gap 7 to form a double structure in which the main body member and the cylindrical member are fixed only at their ends, and the elastic strength of the inner cylindrical member is smaller than that of the outer main body member. By,
The thermal stress of the rotating bearing portion generated by the temperature change is absorbed by the inner cylindrical member and does not act on the main body member having a plurality of outer arms, and the arm derived from the outer surface is not deformed. Therefore, according to the present invention, the change in the positioning position of the magnetic head due to the temperature change is reduced, the variation in the relative positions of the plurality of magnetic heads is eliminated, the amount of thermal off-track is reduced, and high accuracy and high capacity are achieved. There is an effect that a magnetic disk device can be obtained.

[Brief description of the drawings]

1A and 1B are a top view and a cross-sectional view taken along the line AA of a carriage structure of a magnetic disk device for explaining a concept according to an embodiment of the present invention.

FIG. 2 is a diagram showing a simulation result of a thermal off-track amount of a carriage structure of the magnetic disk device of FIG. 1 and a thermal off-track amount of a conventional structure.

FIG. 3 is a cross-sectional view of a part of the carriage showing the first and second embodiments of the present invention .

4A and 4B are a top view and a BB cross-sectional view of a carriage structure of a magnetic disk device showing an example of the related art.

FIG. 5 is a diagram showing exaggerated deformation of the carriage body due to a temperature change in the apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Arm 2 Carriage main body 2a, 2b, 2c Main body 3, 3a, 3b Cylindrical member 4 Fixed part 5 Fixed shaft 6 Rotating bearing 7 Gap 8 Hole 9 Tightening nut 10 Fixed plate 11 Groove 12 Set screw 13 Pin with screw

Claims (2)

(57) [Claims] 1. A magnetic head for recording and reproducing information.
Multiple holding arms are lined up in one direction and derived from the side
Carriage body, and the one
And a pair of rotating bearings
Of the pair of rotary bearings
Magnetic having a fixed axis for rotatably mounting the body
In the carriage structure of the disk device, the pair of rotations
It has a cylindrical member into which the outer ring of a rolling bearing is fitted, and the arm
The carriage body is separated from the carriage body.
Between the member and the cylindrical member in the axial direction including the rotary bearing.
Are separated by a predetermined gap and both ends are fitted with a gap.
At least one end is fixed with screws or pins.
Carriage for magnetic disk drive
Construction. 2. A magnetic head for recording and reproducing information.
Multiple arms that are held are side by side in one direction
A carriage body, and the one-way
A pair of rotating bearings that are fitted in parallel
The carriage body is fitted into the inner races of a pair of rotary bearings.
A magnetic axis having a fixed axis for rotatably mounting the
In the carriage structure of the disk device, the pair of rotations
A book having a cylindrical member into which the outer ring of the bearing is fitted and the arm
The carriage body is separated from the carriage body.
Between the material and the cylindrical member in the axial direction including the rotary bearing
Separate at a specified gap and only fit with a gap at both ends
A carriage structure for a magnetic disk drive, characterized in that both ends are sandwiched and fixed between two plate members .