JPH09245443A - Carriage unit for optical head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low price carriage unit for optical head which is light in weight and can be operate at a high speed. SOLUTION: A carriage 3 loading an optical head 2 of a carriage unit 1 for optical head is movably guided in the radius direction of a disk with a couple of rails 4 via a plurality of slide bearings 5. Bearing supporting members 7, 8, 9 supporting a slide bearing 5 are provided between the carriage 3 and slide bearing 5. The slide bearing 5 is made of a synthetic resin having an internal diameter surface rotatably sliding to the bearing supporting members 7, 8, 9 and an external diameter surface which is in contact at two points in the axial direction with one rail 4. Moreover, the bearing supporting member 7 for supporting the slide bearing being in contact with the left side rail 4 is elastically supported by the carriage 3 via the leaf spring 6 to give a pre- pressure to each slide bearing 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head carriage unit for an optical disk drive, and more particularly to an optical head carriage unit which is light in weight, has less rattling during movement, and is inexpensive.

[0002]

2. Description of the Related Art As an optical disk drive apparatus, for example, a magneto-optical disk drive apparatus a as shown in FIG. 9 is known.
In this apparatus, a carriage unit c on which an optical head b is mounted is driven by a linear motor d to move in a radial direction of a magneto-optical disk e.

An optical head b is provided on the surface of the magneto-optical disk e.
The laser light f emitted from the objective lens g
Irradiated in the form of minute spots via the, the recorded information is reproduced and erased / recorded for writing new information. Erasure and recording of information on the magneto-optical disk e are performed by changing the direction of the magnetic field of the bias magnet h.

The carriage unit c on which the optical head b is mounted is connected to two rails j via a plurality of bearings n.
While being guided by the linear motor d. FIG.
0 and FIG. 11 show an example of a conventional optical head carriage unit c. The carriage m on which the optical head b is mounted is mounted on the magneto-optical disk by a rail j composed of two round bars via a total of six ball bearings n arranged on the one side and two on the other side and one on the other side. e is movably supported in the radial direction. One of the six ball bearings n is attached to the carriage m via an elastic member o for applying a preload, and the carriage m
It is elastically supported by. Other ball bearings n are mounted by inserting a pin shaft q into a pin hole p formed in an inclined portion on the side surface of the carriage m.

[0005]

In recent magneto-optical disk drives, there has been a remarkable demand for higher cost as well as higher speed. Therefore, the carriage unit c has been reduced in cost as well as weight. Is desired.

However, in the case of the conventional optical head carriage unit, at least six expensive ball bearings n are required, so that it is difficult to reduce the cost. Further, there is a limit to the reduction of the weight of the movable part and the speed is increased. There is a problem that it cannot be handled.

Further, if there is an error in the angle of the pin hole p for mounting the ball bearing n, the carriage unit c cannot run smoothly. Therefore, it is necessary to improve the angular accuracy of the pin hole p. However, there is a problem in that processing is difficult and costly when trying to secure it.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide an inexpensive optical head carriage unit which is lightweight, adaptable to high-speed operation, and inexpensive.

[0009]

In order to achieve the above object, an optical head carriage unit according to the present invention comprises:
In a carriage unit for an optical head, in which a carriage on which an optical head is mounted is guided movably in a radial direction of a disk by two rails via a plurality of bearings, a bearing support member supported by the carriage supports the bearings. The bearing is a synthetic resin sliding bearing having an inner diameter surface that slides and rotates on the bearing support member and an outer diameter surface that contacts one rail at two points. The bearing support member that supports the slide bearing in contact with at least one of the rails is elastically supported by the carriage.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a carriage unit for an optical head according to a first embodiment of the present invention, and FIG. 2 is a sectional view of a part of the front view of FIG.

In the optical head carriage unit 1 of this embodiment, a plurality of carriages 3 carrying the optical heads 2 (three carriages in the figure) are interposed in parallel with each other with step differences between them. Rails 4 consisting of two round bars arranged
It is guided by 4 so as to be movable in the radial direction of the disk.

The above three bearings are all made of synthetic resin slide bearings 5, one on the rail 4 side arranged on the left side in FIG. 2, and one on the rail 4 side lower than the left side rail arranged on the right side. Two are arranged. The slide bearing 5
The axial line is arranged in the vertical direction, and a V-shaped peripheral groove 5a is formed on the outer diameter surface of the central portion in the axial direction. In the circumferential groove 5a, the upper and lower slopes 5b and 5c contact the outer peripheral surface of the rail 4, and the slide bearing 5 contacts the rail 4 at two axially separated positions. Here, as the synthetic resin material of the slide bearing 5, a resin obtained by adding an anti-wear agent, a solid lubricant, wax, or the like to POM (polyoxymethylene), or a resin composition containing PA (polyamide) and PE (polyethylene) The thing is preferable. When heat resistance is required for the slide bearing 5, PPS (polyphenylene sulfide), PES (polyether sulfone), etc. may be used with graphite, molybdenum disulfide, wax, fluororesin,
It is preferable to use a solid lubricant such as liquid crystal polymer, polyimide or carbon, or an abrasion resistance improving substance, either alone or in combination and dispersed therein.

Of the three plain bearings 5, FIG.
The first slide bearing 5 arranged on the left side of the carriage is elastically supported by the carriage 3 via a leaf spring 6 bent in three layers in a direction perpendicular to the traveling direction of the carriage 3.
The two slide bearings 5 arranged on the right side of the bearing support member 7 are supported by the second and third bearing support members 8 and 9 directly supported by the carriage 3.

The first bearing support member 7 is an auxiliary member 10 made of a square plate member fixed to the tip of the plate spring 6.
And a shaft 11 which is arranged below the auxiliary member 10 with its axis oriented in the vertical direction and whose upper end is press-fitted and fixed to the auxiliary member 10. An annular spacer 12 made of a copper alloy having excellent slidability and an inner diameter surface of the slide bearing 5 are fitted to the shaft 11 in order, and the inner diameter surface of the slide bearing 5 is slightly slidably rotatable on the shaft 11. Fitted with a gap. In the fitted state, the shaft 11 protruding downward from the slide bearing 5
A retaining ring 13 is attached to the lower end of the slide bearing 5 so that one slide bearing 5 arranged on the left side in FIG.
With the shaft 11 sandwiched between the spacer 12 and the retaining ring 13,
It is held rotatably with respect to.

The second and third bearing supporting members 8 and 9 are both constituted by shafts and have the same structure. The second and third bearing supporting members 8 and 9 are arranged below the carriage 3 with their axes oriented in the vertical direction, and the upper end portions thereof are on the carriage 3. It is fixed by press fitting. The second and third bearing support members 8 and 9 are arranged apart from each other in the traveling direction of the carriage 3, and the inner diameter surface of the slide bearing 5 is slidably rotatable on each bearing support member 8 and 9. Fitted with a slight gap. An annular spacer 15 made of a copper alloy or the like having excellent slidability is fitted to the lower ends of the bearing support members 8 and 9 projecting downward from the slide bearing 5, and
A retaining ring 16 is attached to the lower ends of the bearing support members 8 and 9 below the spacer 15 so that the two slide bearings 5 arranged on the right side in FIG. The bearing support members 8 and 9 are sandwiched between the bearing support members 8 and 9.
It is held rotatably with respect to.

When the carriage 3 is assembled to the rail 4 via the slide bearings 5, the upper and lower slopes 5b, 5 of the V-shaped circumferential groove 5a formed on the outer diameter surface of each slide bearing 5 are mounted.
c contacts the outer peripheral surface of the rail 4 respectively, and the sliding bearing 5
The outer diameter surface of the disk is in contact with the rail 4 at two axially separated positions and is guided and supported so as to be movable in the radial direction of the disk. At this time, since the leaf spring 6 provided on the first bearing support member 7 side is bent in three layers in the direction perpendicular to the traveling direction of the carriage 3, its elastic force is applied to the rotation axis of each slide bearing 5. On the other hand, a force which is almost vertical and perpendicular to the traveling direction of the optical head 2 is exerted, whereby a preload in the horizontal direction (horizontal direction) is applied to each slide bearing 5, and the bending and parallelism of the two rails 4 are increased. The error is absorbed.

Further, since the two rails 4 and 4 are arranged with a step at the top and bottom, a preload in the vertical direction (vertical direction) is applied to each slide bearing 5, and the slide bearing 5 and the bearing support. It is possible to prevent vertical play between the members 7, 8 and 9. In this case, an upward force is applied to the sliding bearing 5 that contacts the higher rail 4 arranged on the left side in FIG. 2, and a downward force is applied to the sliding bearing 5 that contacts the lower rail 4 arranged on the right side. Although a force is applied, in this embodiment, the upper end surface of the slide bearing 5 in contact with the higher rail 4 has an annular spacer 12 made of a copper alloy or the like having excellent slidability.
And the lower end surface of the slide bearing 5 that contacts the lower rail 4 contacts the annular spacer 15 made of a copper alloy or the like having excellent slidability.
2 and 15 are made to function as thrust slide bearings to ensure smooth rotation of each slide bearing 5. Axis 1
If flanges are provided on the bearing support member 1 and the bearing support members 8 and 9, the retaining rings 13 and 16 may not be provided.

As described above, in the optical head carriage unit of this embodiment, since the sliding bearing 5 made of synthetic resin is used as the bearing, the weight of the bearing itself is reduced as compared with the conventionally used ball bearing. In addition, the bearing cost is significantly reduced, and since one slide bearing 5 comes into contact with the rail 4 at two positions vertically and circumferentially separated from each other, the two ball bearings are replaced with one slide bearing. As a result, the number of bearings can be reduced to 1/2, and as a result, the weight of the carriage unit can be drastically reduced and the speed can be increased, and the manufacturing cost can be significantly reduced. Become.

Further, structurally, the bearings can be made small and the number thereof is small, so that the distance between the two rails 4 and 4 can be narrowed, and as a result, the carriage 3 can be made smaller and lighter. The weight reduction of the carriage unit 1 can be further promoted.

Further, the parallelism of the two rails 4 and 4 and the mounting accuracy of the shaft to which the bearings are fitted, which are required in the case of the ball bearing, are not so necessary, and the adjustment at the time of assembling is almost unnecessary. The work can be simplified.

Further, since the bearing is made of the synthetic resin sliding bearing 5 having excellent slidability and abrasion resistance as described above, low friction and excellent durability can be obtained.
In the above embodiment, the leaf springs 6 bent in three layers perpendicular to the traveling direction of the carriage 3 are used to apply a preload in the horizontal direction (horizontal direction) to each slide bearing 5. However, the type and structure of the spring are particularly limited as long as the preload has a force that is substantially perpendicular to the rotation axis of each slide bearing 5 and substantially perpendicular to the traveling direction of the optical head 2. For example, a coil spring or the like may be used instead of the leaf spring 6.

Further, in the above embodiment, the two rails 4 and 4 are arranged so as to have a vertical step, but the two rails 4 and 4 may have the same height. In this case, the first
A spacer 12 is provided between the slide bearing 5 and the auxiliary member 10 that are in contact with the rail 4 on the bearing support member 7 side of
Further, a spacer 15 is arranged between the slide bearing 5 and the carriage 3 which are in contact with the rail 4 on the side of the third bearing support members 8 and 9.

FIGS. 3 and 4 show an optical head carriage unit according to a second embodiment of the present invention. 3 is a plan view, and FIG. 4 is a cross-sectional view showing a part of the front view of FIG. Note that the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Differences from the first embodiment will be described. The leaf spring 17 for preload has a flat plate shape, and is attached to the protrusion 30 provided at the axial end of the left side surface of the carriage 3. The bearing support member 7 supported by the leaf spring 17 is located between the carriage 3 and the rail 4 and in the axial center of the carriage 3, and the two rails 4, 4 are provided.
The left and right heights of are reversed. Since the bending direction of the leaf spring 17 is perpendicular to the rail 4, the flat spring 1
As it is 7, preload is applied perpendicularly to the rotation axis of the slide bearing 5. The effect is the same regardless of which of the left and right rails 4 and 4 is higher, but in FIG. 4, the vertical (vertical) force applied to the left and right slide bearings 5 is opposite to that in the first embodiment. Therefore, the positions of the annular spacers 12 and 15 are opposite to those in the first embodiment. The other configurations are the same as those in the first embodiment, and therefore will be omitted.

FIG. 5 and FIG. 6 show an optical head carriage unit according to a third embodiment of the present invention. FIG. 5 is a plan view, and FIG. 6 is a sectional view showing a part of the front view of FIG. The same parts as those of the first and second embodiments are designated by the same reference numerals and the description thereof will be omitted.

Differences from the second embodiment will be described. The tip of the leaf spring 17 is a rectangular auxiliary member portion 18 provided horizontally, and the auxiliary member portion 18 is the leaf spring 1.
7 is bent at a right angle with respect to the other parts of the leaf spring 17
And oneness. The bearing support member 7 is composed of a shaft,
The bearing support member 7 is caulked and attached to the auxiliary member portion of the leaf spring. This has the advantage that the number of parts can be reduced. The other configurations are similar to those of the first and second embodiments, and therefore their explanations are omitted.

FIGS. 7 and 8 show an optical head carriage unit according to a fourth embodiment of the present invention. 7 is a plan view and FIG. 8 is a cross-sectional view showing a part of the front view of FIG. 7. The same parts as those of the first to third embodiments are designated by the same reference numerals and the description thereof will be omitted.

A leaf spring 17 for preload is attached to a protrusion 30 provided at the center of the side surface of the carriage 3 in the axial direction. The leaf spring 17 extends from the protrusion 30 to both sides in the axial direction. Bearing support members 7 are supported on both axial ends of the leaf springs 17, and the slide bearings 5 are supported on the bearing support members 7. This has the advantage of being stronger against moments than the first to third embodiments. The other configurations are similar to those of the first to third embodiments, and therefore their explanations are omitted.

[0029]

As is apparent from the above description, in the present invention, since a synthetic resin plain bearing is used as a bearing, the weight of the bearing itself can be reduced as compared with a conventional ball bearing. The bearing cost is greatly reduced, and one slide bearing contacts two places in the circumferential direction of the rail, so that two ball bearings are replaced with one slide bearing, reducing the number of bearings. As a result, the weight of the carriage unit can be significantly reduced, and the speed can be increased, and the manufacturing cost can be significantly reduced.

Further, structurally, the bearings can be made smaller and the number thereof can be reduced, so that the distance between the two rails can be narrowed, and as a result, the carriage can be made smaller and lighter, and the carriage unit can be made smaller. The weight reduction can be further promoted.

Further, the parallelism of the two rails and the mounting accuracy of the shaft to which the bearings are fitted are not required so much in the case of the ball bearing, and the adjustment at the time of assembly is easy and the assembly work can be simplified. become.

[Brief description of drawings]

FIG. 1 is a plan view of an optical head carriage unit according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a part of the front view of FIG. 1;

FIG. 3 is a plan view of an optical head carriage unit according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view of a part of the front view of FIG.

FIG. 5 is a plan view of a carriage unit for an optical head according to a third embodiment of the present invention.

6 is a cross-sectional view of a part of the front view of FIG.

FIG. 7 is a plan view of a carriage unit for an optical head according to a fourth embodiment of the present invention.

FIG. 8 is a cross-sectional view of a part of the front view of FIG. 7.

FIG. 9 is an explanatory schematic diagram for explaining a magneto-optical disk drive device.

FIG. 10 is a plan view of a conventional optical head carriage unit.

11 is a cross-sectional view of a part of the front view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical head carriage unit 2 ... Optical head 3 ... Carriage 4 ... Rail 5 ... Sliding bearing 6 ... Leaf spring 7 ... First bearing support member 8 ... Second bearing support member 9 ... Third bearing support member

Claims (1)

[Claims] 1. A carriage unit for an optical head, wherein a carriage carrying an optical head is guided by two rails via a plurality of bearings so as to be movable in a radial direction of a disk. A bearing support member supported by the carriage. Is a synthetic resin slide bearing having an inner diameter surface that slides and rotates on the bearing support member and an outer diameter surface that contacts two rails with respect to one rail. ,
A carriage unit for an optical head, wherein a bearing support member that supports the slide bearing that contacts at least one of the two rails is elastically supported by the carriage.