JPH02226557A - Guide mechanism of actuator for disk device - Google Patents

Abstract

PURPOSE:To improve the positioning accuracy of a magnetic head by stabilizing the travel of an actuator by providing a rolling element, and forming a mechanism so as to support a guide rail with a housing by bringing into contact with the rolling element. CONSTITUTION:The cross-section of the guide rail 4 is formed in hexagon, and two planes 41 and 42 are supported out of six planes. Also, a recessed part is provided at the housing 5, and balls 11a-11e are arranged in the recessed part. The balls 11a-11e are provided at five places in total: three places 11a, 11b, and 11c on the vertical plane 41 of the guide rail 4, and two places 11d and 11e on the horizontal plane 42, and the contact point of the planes with the guide rail forms the supporting part of the guide rail 4. Furthermore, the guide rail 4 is fixed on the housing 5 with a screw 12, however, a spring 13 is interposed between the screw 12 and the housing. By employing such constitution, it is possible to prevent a relative position generated between the guide rail and the housing from being fluctuated even when temperature change occurs in a magnetic disk being operated, which improves the positioning accuracy of the magnetic head by stabilizing the travel of the actuator.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a guide mechanism for an actuator for a disk device, and particularly to a disk device equipped with a linear access type actuator that moves a head in the radial direction of the disk.

[Conventional technology]

In recent years, as the storage capacity of magnetic disk drives has increased, particularly high precision has been required for actuators that position magnetic heads on magnetic disks. In order to meet this requirement, high-precision servo control and spindles are of course required, but in particular the accuracy and stability of the guide rails that guide the carriage have become issues. That is, if the support structure of the guide rail is poor and unstable, or if the guide rail is deformed, the carriage will tilt. Particularly in the case of a deformation mode in which the straight line connecting the data head and the servo head is inclined, the data head goes off-track by the amount of this inclination, resulting in a deterioration of positioning accuracy.

A conventional guide mechanism for an actuator for a magnetic disk device, as described in U.S. Pat. No. 4,427,905, includes a cylindrical guide rail 121 that is brought into close contact with a housing 122 that has two flat surfaces, and fixed with screws 123. There are known ways to do this. This is shown in FIG.

[Problem to be solved by the invention]

In the above prior art, the cylindrical guide rail and the housing are in line contact. The state is shown in FIGS. 6 and 7. Here, the cylinder 21 and the curved semi-cylinder 23 correspond to the guide rail, and the plane 20 and the curved quasi-plane 2
2 corresponds to a housing. When the cylinder 21 comes into contact with the plane 20, ideally the two will meet along the tangent line A shown by the dotted line in FIG.
Contact is made in area A'. However, in reality, it is impossible to create a perfect geometric shape. Therefore, strictly speaking, as shown in FIG. 7, the guide rail becomes a semicircular column 23 and the housing becomes a quasi-plane 22, so that their contact areas are no longer tangential lines, such as B□, B, for example.

Similarly, consider the case where the guide rail is prismatic. The contact state is shown in FIGS. 8 and 9. Square pillar 24
, the quasi-prismatic column 25 corresponds to a guide rail, and the plane 20 and quasi-plane 22 correspond to a housing. When the prism 24 and the plane 20 come into contact, ideally they contact at one plane C of the prism 24, as shown by the shaded area C in FIG. However, for the same reason as mentioned above, strictly speaking, as shown in FIG. , D, and D3.

As described above, in reality, it is not possible to specify the contact point between the guide rail and the housing, making it difficult to stably attach the guide rail to the housing. This causes the carriage to tilt, leading to a deterioration in positioning accuracy as described above.

Further, the guide rail is generally made of a steel-based material such as stainless steel because wear resistance is required, and the housing is made of an aluminum-based alloy having the same coefficient of linear expansion as the magnetic disk substrate. Therefore, since the guide rail and the housing have different coefficients of thermal expansion, when the ambient temperature changes, the guide rail deforms due to the bimetallic phenomenon, and the leakage causes the carriage to tilt, resulting in the deterioration of positioning accuracy as described above (especially Become.

An object of the present invention is to provide a linear actuator for use in a disk device, in which the guide rail of the actuator part can be supported in a housing accurately and stably, and the distance between the guide rail and the housing can be improved. An object of the present invention is to provide a guide mechanism for an actuator for a disk device that can reduce relative position fluctuations as much as possible.

[Means to solve the problem]

In order to achieve the above object, the present invention is configured such that a rolling element such as a ball is disposed between a guide rail and a housing that supports it, so that the guide rail and the housing are in contact with each other through the rolling element. It is.

In this case, a preload means is provided to press the guide rail and the housing against each other via the rolling elements so that the guide rail and the rolling element and the rolling element and the housing come into contact with each other.

For example, a recess is provided in the housing, and the rolling element is disposed within the recess.

[Effect]

For example, when the guide rail is supported by being pressed against the housing via the ball, the guide rail comes into contact with the ball and is supported by the housing.

By arranging these balls at optimal locations, the guide rail can be stably supported.

For example, the guide rail is constructed by providing at least two planes parallel to its longitudinal direction, and among the planes, three parts that are not on the same straight line of the first plane and two parts of the second plane are arranged. The ball is arranged so that it makes contact with the
This is achieved by supporting the guide rail through the ball.

Here, the guide rail is of a hexagonal cross section, for example, and the support means is constructed by providing five recesses in the housing and arranging rolling elements such as balls in the recesses. As a result, the accuracy of the guide rail work was a little poor.

Even if the guide rail undergoes thermal deformation or the like, it is always supported by the housing by the five contact points provided on the guide rail. Therefore, the guide rail can be accurately attached to the housing.
Moreover, it can be installed stably.

Further, if the guide rail and the housing are made of different materials and have different coefficients of linear expansion, a difference in thermal expansion will occur between them when the temperature increases. However, even in this case, the guide rail and the housing are in contact with each other via the rolling elements, so the rolling of the rolling elements causes relative sliding between the guide rail and the housing, making it difficult to eliminate thermal distortion. can. Therefore, even if the temperature changes, thermal stress is not generated in both and the guide rail is not deformed, so that the posture of the actuator guided by this can also be kept constant.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 3 is an overall schematic diagram of a magnetic disk drive having an actuator guide mechanism, which is an embodiment of the present invention. This magnetic disk device includes a magnetic disk disk 1, a spindle 2,
It consists of a magnetic head 3, a guide rail 4, a housing 5, a carriage 6, a bearing 7, a coil 8, and a permanent magnet 9.

A magnetic disk 1 is fixed by a spindle 2 and rotates at high speed. A magnetic head 3 for recording and reproducing data on the magnetic disk 1 is mounted on a carriage 6. A coil 8 is provided at the rear of the carriage 6, and the coil 8 and permanent magnet 9 constitute a linear motor.

Then, the carriage 6 is moved in the α direction by being moved by this linear motor. Here, the carriage 6 is held on the guide rail 4 via a bearing 7.

FIG. 1(α) is a front view showing details of the guide rail mounting portion of the actuator of this embodiment. FIG. 1(b) is a side view thereof. The guide rail 4 has a hexagonal cross section, and two sides 41 and 42 of the guide rail 4 are supported by the housing 5. The guide rail 4 is made of stainless steel, for example, and the housing 5 is made of aluminum, for example. 11c
L~lie is a support part for supporting the guide rail 4, a recessed part is provided in the housing 5, and balls lla~lie are provided in the housing 5.
11(l).This ball 11α~l
ie is the vertical surface 4 of the guide rail 4 as shown in FIG.
There are three locations in 1: 1lcL, llb, and lie.

A total of five locations, two locations, lid and lie, are provided on the horizontal surface 42.

Next, the functions of this embodiment will be explained. Two of the six hexagonal faces 41 and 42 of the guide rail 4 are not in full contact with the housing 5, but are in contact with the housing 5 through five balls 11α to 11. 4 and the housing 5 are not in contact with each other. In this way, since the guide rail 4 is supported at the contact points with the balls 11α to 11ie, the balls 11a to 11a will not roll even if the machining accuracy is not high or even if a bimetal phenomenon occurs. Accordingly, the guide rail 4 can be supported with high precision in the same state at all times without generating thermal stress on the guide rail 4 and the housing 5.

Furthermore, when the magnetic disk drive shown in FIG. 3 actually operates, the guide rail 4 may be thermally deformed due to the heat generated by the coil 8, etc., and the guide rail 4 may be caused to pass through the bearing 7 due to the high-speed movement of the carriage 6 in the α direction. Various forces are applied to the In this case, the guide rail 4 has six degrees of freedom. That is, as shown in FIG. 2, there are three degrees of freedom: the X direction, which is the longitudinal direction of the guide rail, the Y direction and the Z direction, which are perpendicular to the X direction and perpendicular to each other.

It has three degrees of freedom in rotational directions, rotating around the Y and Z axes.

In this embodiment, five balls 1171 to 11a are provided so as to effectively restrict five degrees of freedom, excluding the X-axis direction, among these six degrees of freedom. In Fig. 2, the force exerted by the balls lla to lle on the guide rail 4 is 11α
Indicated by arrows ~110'.

The degrees of freedom in the Y-axis direction are 11α, llb', 110',
The degree of freedom in the Z-axis direction is lid' lie, the degree of freedom around the
It is limited by α, llb'. Note that the degree of freedom in the X direction is not supported because the thermal displacement of the guide rail 4 is
The purpose is to move in the opposite direction.

Here, in order to specify the contact area as described above, it is preferable that the number of contact areas is small. Then, if the five degrees of freedom mentioned above are restricted, 11a llb'
It is sufficient to have the supporting force of lie and lid'.

However, the balls 11cL-lie are not fixed with adhesive or the like, but are only supported by contacting the guide rail 4 by inserting the balls 11α-lie into the recesses provided in the housing 5. . This is ball 11
If α~lie is fixed, the thermal expansion coefficients of the guide rail 4 and the carriage 8 will be different, and a bimetal phenomenon will occur due to temperature change, causing the guide rail 4 to deform. Since ~lie is a ball, the frictional force is only rolling friction, and the generation of thermal stress can be reduced.

Note that the guide rail 4 is fixed to the housing 5 with screws 12, as shown in FIG. 4 (OL) and (b).
A screw 13 is inserted between the housing 5 and the screw 12 so that the posture of the guide rail 4 is not restricted by the screw 12, and so that the guide rail 4 and the housing 5 are pressed against each other via the balls 11α to lie. It is arranged. As a result, the guide rail 4 is always stably supported by the housing 5 via the balls 11α to 11lie.

As described above, according to this embodiment, even if the machining accuracy is poor or there is thermal deformation, the contact area does not change.
It can support guide rails with high precision, and
Since the five degrees of freedom of the guide rail are restricted, the guide rail can be supported with extremely high stability.

〔Effect of the invention〕

According to the present invention, the guide rail is attached to the housing with high precision, and even if there is a temperature change during the operation of the magnetic disk, it is possible to prevent relative positional fluctuations between the guide rail and the housing. The actuator runs stably and the positioning accuracy of the magnetic head improves.

[Brief explanation of the drawing]

FIG. 1 is a detailed view of the guide rail attachment part of the actuator according to the first embodiment of the present invention, (, i) is a front view and (
b) is a side view, FIG. 2 is a diagram for explaining the degree of freedom of the guide rail, FIG. 3 is a diagram showing the overall configuration of the magnetic disk device, and FIG. 4 is a diagram showing the state in which the guide rail is fixed to the housing. FIG. 5 is a perspective view, FIG. 5 is a side view, FIG. 5 is a diagram showing the fixed state of the guide rail and housing in the prior art, and FIGS. It is a figure for explaining the contact state of a housing and a guide rail. 3...Magnetic head, 4...Guide rail, 5...
Housing, 6... Carriage, 7... Bearing, 8...
...Coil, 9...Permanent magnet, 1o...Supporting member,
11... Support part, 12... Screw, 13... Spring. Shi No.? Mouth system 6 brutality 8I! 1 Bangkok (OL) Cb) /3 Musikoku Fl'70 N59 Power S

Claims (3)

[Claims] (1) A carriage on which the head is mounted, a driving means for driving the carriage in the radial direction of the disk, a bearing provided on the carriage, and the bearing travels in contact with each other to guide the movement of the carriage. In a guide mechanism for an actuator for a disk device that has a guide rail and a housing that supports the guide rail, a rolling element is disposed between the guide rail and the housing, and the guide rail is supported by the housing in contact with the rolling element. An actuator guide mechanism characterized in that: (2) The guide mechanism for an actuator for a disk device according to claim 1, wherein the rolling element is a ball, and a recess is formed in the housing, and the ball is disposed in the recess. (3) The guide mechanism for an actuator for a disk device according to claim 1, further comprising a preload means for pressing the guide rail against the housing via the rolling element.