JPH07296391A - Carriage unit for optical head - Google Patents

Abstract

PURPOSE:To obtain an inexpensive light weight carriage unit for optical head which can deal with a high speed operation. CONSTITUTION:A carriage 9A for carrying an optical head is supported movably in the radial direction of an optical disc by means of two rails 13 through a plurality of bearings 12, 20. In this carriage unit for optical head, the bearing is provided with at least one or more sliding bearings 20 and at least one of the plurality of bearings is supported by a resilient member 22 for the purpose of pre-loading.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a carriage unit for an optical head of an optical disk drive device, and more particularly,
The present invention relates to a carriage unit for an optical head that is lightweight, has little rattling during movement, and is low cost.

[0002]

2. Description of the Related Art As an optical disk drive, for example, FIG.
There is known a magneto-optical disk drive device 1 as shown in FIG. This is a so-called separated type in which the movable optical system 2 and the fixed optical system 3 that are relatively lightweight are separated from each other in order to make the optical head as light as possible and to increase the speed. The movable optical system 2 includes an actuator 8 having a built-in objective lens 7 for forming a rising mirror 5 as a deflecting means for bending the horizontally incident laser beam 4 and a minute spot on the surface of the magneto-optical disk 6. The carriage unit 9 having the actuator 8 mounted thereon is conveyed by the linear motor 10 in the radial direction of the magneto-optical disk 6.

A fixed optical system 3 is provided on the surface of the magneto-optical disk 6.
The laser beam 4 emitted from the laser beam is emitted in a spot shape via the rising mirror 5 of the actuator 8 of the movable optical system 2, and erased for reproducing recorded information or writing new information. Make a record. The erasing / recording of information on the magneto-optical disk 6 is performed by changing the direction of the magnetic field of the bias magnet 11.

The carriage unit 9 equipped with the actuator 8 is conveyed by the linear motor 10 while being guided by the rail 13 via the bearing 12. At that time, the carriage unit 9 slightly moves between the bearing 12 and the rail 13. If there is a certain amount of backlash, the carriage unit 9 causes a motion or yawing motion (yawing, pitching, rolling) in the vertical direction with respect to the horizontal moving direction. As a result, the optical axis of the laser beam 4 emitted to the raising mirror 5 of the movable optical system 2 is offset or the incident angle is changed, and the efficiency of focusing the laser beam 4 on the disk film surface is deteriorated. . Therefore, it is necessary that the carriage unit 9 does not rattle during movement.

18 and 19 show an example of a conventional carriage unit for such a separate type optical head. The carriage 9A on which the actuator 8 is mounted has a radius of the magneto-optical disk 6 by a rail 13 consisting of two round bars through a total of six ball bearings 12 arranged on one side, four on the upper side and two on the other side. It is supported so that it can move in any direction. One of the six ball bearings 12a is attached to the carriage 9A by an elastic member 14 for applying a preload so that the ball bearings 12a can be guided without any rattling with the rail 13 during movement.

On the other hand, in the case of another conventional optical head carriage unit shown in FIGS. 20 and 21, the carriage 9A on which the actuator 8 is mounted has two oil-impregnated bearings made of cylindrical sintered metal. It is movably supported by two rails 13 via 15. In this conventional example, the oil-impregnated bearing 15, which is a sliding bearing, has a larger friction coefficient than that of the ball bearing, and in order to prevent an increase in driving force by that amount, normally, bearing preload is not applied. Therefore, since the backlash during movement cannot be avoided, the optical head cannot be separated, and it is used for an integrated optical head in which a movable optical system and a fixed optical system are integrated.

[0007]

Recently, the magneto-optical disk drive device has a tendency to be required to have a higher cost and a lower cost. Therefore, in addition to the weight reduction of the movable part of the optical head, the low cost of the carriage unit is required. Cost reduction is desired. However, in the case of the conventional separation type optical head carriage unit of FIGS. 18 and 19, it is difficult to reduce the cost because at least six expensive ball bearings are required, and there is a limit to the weight reduction of the movable portion. There was a problem.

On the other hand, in the case of the optical head carriage unit shown in FIGS. 20 and 21, since an oil-impregnated bearing made of a low-priced sintered metal is used, it is advantageous in terms of cost. Does not apply preload,
There is a problem that it must be used exclusively for an integrated type optical head that allows play during movement, and is not suitable for high speed operation.

Therefore, the present invention has been made by paying attention to the above-mentioned conventional problems, and by changing the structure of a plurality of bearings from the conventional one, a lightweight and inexpensive optical head carriage capable of coping with speeding up. The purpose is to provide a unit.

[0010]

SUMMARY OF THE INVENTION The present invention relates to an optical head carriage unit in which a carriage carrying an optical head is supported by two rails via a plurality of bearings so as to be movable in the radial direction of an optical disk. The bearing includes at least one slide bearing, and at least one of the plurality of bearings is elastically supported to apply a preload.

[0011]

In the optical head carriage unit of the present invention, at least one or more lightweight and low-priced slide bearings are used, so that the entire carriage unit becomes light in weight and low in cost. In addition, by applying a preload to the bearing, there is less play during movement of the optical head, and it is possible to increase the speed of the carriage unit for the separate type optical head.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. The same or corresponding parts as in the conventional case are designated by the same reference numerals. FIG. 1 is a plan view of a first embodiment of the present invention, and FIG. 2 is a front view. As the bearings that support the carriage 9A, three ball bearings 12 and two slide bearings 20 are used. Two ball bearings 12 are fixed on one upper side surface of the carriage 9A and one on the other upper side surface via a support shaft 21, and the outer peripheral surface of the ball bearing is pressed against two round bar-shaped rails 13. ing. The sliding bearing 20 of this embodiment is a synthetic resin formed in a sheet shape by filling a fluororesin PTFE (polytetrafluoroethylene) with an abrasion property improving substance such as econol, graphite, carbon fiber, molybdenum disulfide, and polyimide. This is a slide bearing made of steel, supported by leaf springs 22 and attached to both sides of the lower surface of the carriage 9A so as to sandwich the rail 13 together with the ball bearing 12. This leaf spring 22
The preload is applied to each bearing due to the elasticity of, and the backlash with the rail 13 does not occur.

When the carriage unit 9 constructed as described above is mounted on the magneto-optical disk drive device 1 shown in FIG. 17 and the carriage 9A is driven by the linear motor 10 in the radial direction of the magneto-optical disk 6, a slight play is generated. Without being guided by the rail 13, the carriage unit 9 does not move vertically or swing. Therefore, the optical axis of the laser beam 4 emitted to the rising mirror 5 of the movable optical system 2 is offset or the incident angle is changed, and the condensing efficiency of the laser beam 4 on the disk film surface is deteriorated. Can be completely prevented.

Further, since the supporting bearing has a hybrid structure in which the ball bearing 12 and the sliding bearing 20 made of synthetic resin having a small friction coefficient are combined, the friction does not increase even if a preload is applied, and the linear motor drive The power is small. The sliding bearing 20 made of synthetic resin has better slidability and is lighter than the oil-impregnated bearing made of sintered metal. Therefore, it has excellent durability and is suitable for speeding up.

FIG. 3 shows a modification of the first embodiment.
In this case, instead of supporting the two plain bearings 20 by separate leaf springs 22, a common leaf spring 22 is used.
We support in A. A second embodiment is shown in FIGS.
In this embodiment, as a bearing for supporting the carriage 9A,
The first point is that two ball bearings 12 and two (two or more) sheet-shaped slide bearings 20 are used, and one ball bearing is supported via a leaf spring 22. Is different from the embodiment described above.

That is, one ball bearing 12 is fixed to one upper side surface of the carriage 9A via the support shaft 21, and the other one is fixed to the other upper side surface of the carriage 9A via a leaf spring 22. On the other hand, a sheet-shaped plain bearing 20
Are directly bonded onto the slope 23 formed on the lower portion of the aluminum alloy carriage 9A. Each bearing is a leaf spring 2
Since the rail 9 is pressed against the rail 13 by the elasticity of 2 and a preload is applied, there is no backlash when the carriage 9A moves.

The operation and effect of this embodiment are similar to those of the first embodiment. 6 and 7 show a third embodiment. In this embodiment, one ball bearing 12 and three button-shaped slide bearings 24 are used as bearings for supporting the carriage 9A. The ball bearing 12 has a leaf spring 22 on one upper side surface of the carriage 9A. It is fixed. On the other hand, the button-shaped slide bearing 24 is, for example, a molded product of a synthetic resin in which PPS (polyphenylene sulfide) is filled with a wear-resistant resin, and the support protrusion 25 is integrally molded. Then, one slide bearing 24 is fixed by inserting a support protrusion 25 on a slope 23 formed on the lower part of one side surface of the carriage 9A, and the other two slide bearings 24 are formed in the middle of the other side surface. Slopes 26 facing each other vertically in a V-shaped groove 26
The support protrusions 25 are inserted into and fixed to a and 26b, respectively. One rail 13 is clamped by a slide bearing 24 in a V-shaped groove 26, the other rail 13 is clamped by a ball bearing 12 and a slide bearing 24, and a preload is applied to each bearing by a leaf spring 22.

The operation and effect of this embodiment are similar to those of the first embodiment. A fourth embodiment is shown in FIGS. In this embodiment, two ball bearings 12 and two cylindrical slide bearings 28 are used as bearings for supporting the carriage 9A. The two ball bearings 12 are on one side surface side of the carriage 9A so as to sandwich one rail, one is fixed to the upper surface of the carriage 9A via a leaf spring 22, and the other one is below the side surface of the carriage 9A. It is fixed via a support shaft 21.

On the other hand, the two cylindrical plain bearings 28 are
Rail hole 2 formed near the other side surface of the carriage 9A
They are fitted and fixed to the open end portions of 9, respectively. The one rail 13 is sandwiched between two upper and lower ball bearings 12, and the other rail 13 is passed through a rail hole 29 and held by a cylindrical slide bearing 28, so that the carriage 9A has a rail 13.
The bearings are preloaded by leaf springs 22 and guided to each bearing without play.

The cylindrical slide bearing 28 is made of PTFE in which the inner surface of the rail hole 29 penetrating the aluminum alloy carriage 9A is filled with a wear property improving substance having good lubricity.
Forming by adhering a sheet-shaped resin containing as a main component has the advantage that the structure is simple and light. Further, in this embodiment, a cylindrical oil supply member 30 made of a felt-like porous member is mounted inside the rail hole 29, and a lubricant such as oil or grease is impregnated into the oil supply member 30 to supply oil to the slide bearing 28. This reduces friction and improves durability. However, the refueling member 30 may be omitted depending on the usage conditions.

The operation and effect of this embodiment are similar to those of the first embodiment. A fifth embodiment is shown in FIGS. In this embodiment, three slide bearings 31 are used as bearings for supporting the carriage 9A, one of which is elastically supported and preloaded. This prevents looseness between the carriage 9A and the rail 13 during movement. The slide bearing 31 is made of a synthetic resin containing PPS or nylon 6 as a main component, and is filled with an abrasion resistant resin. As shown in FIG. 12, the shape is a concave shape having a valley portion 31b between two crests 31a, and the rail 13 is embraced by the two crests 31a. Further, a pin-shaped support protrusion 32 is provided on the opposite side of the valley portion 31b, and the support protrusion 32 is fitted into the carriage 9A by a loose fit and supported. Elastic support of the slide bearing 31 is achieved by the leaf spring 33 attached to the carriage 9A.
The end portion of the support protrusion 32 protruding inward of the carriage 9A is elastically pressed outward.

The slide bearing 31 having such a structure has the advantage that the same shape can be mass-produced by injection molding and the cost can be reduced. Further, since one slide bearing 31 is in contact with the outer peripheral surface of the rail 13 at two points in the circumferential direction by the two crests 31a, the three slide bearings 31 are in contact with the rail at six convenient points. 13 has the advantage that the carriage 9A can be stably supported and the number of bearings is reduced as compared with the conventional case.

Further, since the contact with the rail 13 is a line contact, foreign matter is less likely to be caught in the rail 13. Further, since it is supported by being fitted to the carriage 9A with the support projection 32 by a loose fit, there is an advantage that the slide bearing 31 can freely move following the rail 13 even if the alignment is bad.

13 to 16 show a sixth embodiment. In this embodiment, for the purpose of reducing the coefficient of friction and further improving the durability, the valley 31b of the sliding bearing 31 is made of a felt-like porous member in which a lubricant such as oil or grease is impregnated. The third embodiment differs from the fifth embodiment in that the coil spring 35 is provided (FIG. 16) and that a coil spring 35 is used instead of the leaf spring as a means for applying a preload.
FIG. 16 is an enlarged view of the preload structure. After the coil spring 35 is mounted in the cylindrical spring mounting hole 36 provided on the side surface of the carriage 9A, the coil spring 35 is fitted into the carriage 9A through the support protrusion 32 of the slide bearing 31 with a loose fit. , Then carriage 9
The end portion of the support protrusion 32 protruding inward of A is deformed by applying heat to form an expansion stopper 37 on the outer periphery.

Other configurations, operations and effects are similar to those of the fifth embodiment. In each of the first to fourth embodiments, the standard ball bearing 12 is used, but in order to reduce the weight of the bearing as much as possible, the inner ring is omitted and the support shaft 21 for attachment to the carriage 9A is directly attached. Alternatively, a shaft bearing having an inner ring raceway may be used. Further, in each of the above embodiments, the rail 13 is a round bar, but a rail having a polygonal cross section may be used.

Further, as the elastic support mechanism of the bearing, the one using the leaf springs 22, 22A, 33 and the coil spring 35 of the embodiment has the advantage of being simple and lightweight, but is not limited to this. Instead, it may be supported by an elastic body such as rubber. Further, although the elastic member using only one elastic member has been described, the present invention is not limited to this, and it is also possible to use two or more elastic members for preloading.

Further, in the fourth embodiment, the oil supply member 30 is
Although the oil supply members 34 are used in the sixth embodiment, the synthetic resin slide bearings themselves may be made of an oil-impregnated resin instead of the oil supply members. Alternatively,
In the case of the button-shaped synthetic resin slide bearing 24 or the concave slide bearing 31 containing PPS or nylon 6 as a main component, a resin containing a lubricant is integrally molded around the contact portion with the rail 13, The slip surface may be lubricated with a lubricant that oozes out.

Further, the slide bearing is not limited to the one made of the synthetic resin of the embodiment, but may be, for example, a fibrous lubricating member mainly composed of a ceramic sheet or paper.

[0029]

As described above, according to the optical head carriage unit of the present invention, a plurality of bearings for supporting the carriage mounting the optical head on the rails are provided.
Since at least one slide bearing is provided and at least one of the plurality of bearings is elastically supported so as to apply a preload, the weight of the movable part of the optical head can be reduced and the speed can be increased. There is an effect that can be.

That is, in the conventional one using six ball bearings, the weight of the entire ball bearing is 20 to 3 of the entire carriage.
While this invention occupies 0%, the present invention promotes weight reduction by replacing a part or all of the ball bearings with a sliding bearing such as a lightweight synthetic resin, and at the same time reduces the number of expensive ball bearings to be used. There is also the effect of reducing costs and reducing costs.

Further, compared with the conventional one in which a sintered metal oil-impregnated sliding bearing is used as the supporting bearing, a preload can be applied to the bearing within the range permitted by the driving force of the linear motor, and there is no play during movement of the carriage. As a result, there is an effect that it can be used not only in the integrated type optical head but also in the separated type optical head.

[Brief description of drawings]

FIG. 1 is a plan view of a first embodiment of the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is a front view of a modification of the first embodiment.

FIG. 4 is a plan view of the second embodiment of the present invention.

FIG. 5 is a front view of FIG.

FIG. 6 is a plan view of the third embodiment of the present invention.

FIG. 7 is a front view of FIG.

FIG. 8 is a plan view of the fourth embodiment of the present invention.

9 is a front view of FIG. 8. FIG.

FIG. 10 is a perspective view of a fifth embodiment of the present invention.

11 is a plan view of FIG.

12 is a front view of FIG.

FIG. 13 is a perspective view of a sixth embodiment of the present invention.

FIG. 14 is a plan view of FIG.

FIG. 15 is a front view of FIG.

16 is a partially enlarged view of FIG.

FIG. 17 is an explanatory diagram of a magneto-optical disk drive device.

FIG. 18 is a plan view of an example of a conventional carriage unit.

FIG. 19 is a front view of FIG. 18.

FIG. 20 is a plan view of another example of the conventional carriage unit.

21 is a front view of FIG. 20. FIG.

[Explanation of symbols]

 9 Carriage unit 9A Carriage 12 Ball bearing 13 Rail 20 Sliding bearing 22 Elastic member (leaf spring) 22A Elastic member (leaf spring) 24 Sliding bearing 28 Sliding bearing 31 Sliding bearing 33 Elastic member (leaf spring) 35 Elastic member (coil spring)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Ikki Sakaya 1-8-18 Otoko, Fujisawa City, Kanagawa Prefecture (72) Hideki Okaya 480-1-332 Nakamurahara, Odawara City, Kanagawa Prefecture

Claims (1)

[Claims] 1. A carriage unit for an optical head in which a carriage carrying an optical head is movably supported in a radial direction of an optical disk by two rails via a plurality of bearings, wherein the bearings include one or more slide bearings. A carriage unit for an optical head, comprising at least at least one of a plurality of bearings, which is elastically supported to apply a preload.