JPH08203223A - Carriage driving mechanism - Google Patents

Abstract

PURPOSE: To obtain a carriage driving mechanism by which a carriage can be moved stably by making a disturbance caused by the imbalance or the like of the friction of a guide member not influence the driving force of the carriage. CONSTITUTION: A carriage driving mechanism 2 is constituted of a guide member 4 and a driving means 8 for a carriage. The driving means 8 is composed of a linear motor 14 and an arm 16. The arm 16 is divided in two so as to correspond to the bidirectional operating property (an access operation and a tracking operation) of the carriage 6. Pressure parts 30, 32 which correspond to positions of the center of gravity of side faces 10a, 10b perpendicular to a movement direction are formed at tip parts of respective arm bodies 24, 26. Brackets 34, 36 which comprise faces containing the positions of the center of gravity are formed at the side faces 10a, 10b. When the carriage 6 is moved, its driving force acts on one point in a concentrated manner in the position of the center of gravity in a tip face part in the movement direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carriage drive mechanism for moving, for example, a movable element of an optical system,
In particular, it relates to a mechanism suitable for driving a carriage of an optical disk device.

[0002]

2. Description of the Related Art In an optical disk apparatus, in order to improve the accuracy of reading information and the like, there is generally required a technology for moving a carriage equipped with an optical head in the radial direction of the optical disk with high accuracy and stability. As a prior art proposed for such a purpose, Japanese Patent Application Laid-Open No. 5-27482
No. 1, JP-A-5-151580, and JP-A-3-153.
For example, Japanese Patent Laid-Open No. 194733, Japanese Patent Laid-Open No. 3-1375, Japanese Patent Laid-Open No. 4-335213, Japanese Patent Laid-Open No. 3-76030 and the like can be cited.

Among these, Japanese Patent Application Laid-Open No. 5-274821,
Also, each of those disclosed in Japanese Patent Application Laid-Open No. 5-151580 has a basic structure in which a carriage is movably arranged between two parallel guide shafts and is moved by a linear motor as a driving means. ing.

The former feature is that the guide shaft is constantly rotated by the drive motor, and the friction (static / dynamic friction) generated between the bearing of the carriage and the guide shaft is unified only in the dynamic friction state to reduce the friction resistance. The feature of the latter is that the guide shaft is slightly vibrated by the piezoelectric element to similarly reduce the frictional resistance.

Further, Japanese Patent Application Laid-Open No. 3-194733 and Japanese Patent Application Laid-Open No. 3-1375 discloses that the driving force generating shaft of the drive motor of the carriage, the shaft center of the guide shaft, and the optical head ( (Including the carriage) are arranged on the same straight line to improve the efficiency of the effective driving force.

Further, in the ones disclosed in JP-A-4-335213 and JP-A-3-76030, the former feature is that the center of the drive force generating shaft of the drive motor of the carriage and the optical head (carriage). When the center of gravity of the carriage is deviated, the auxiliary coil of the linear motor, which is the drive motor, applies force in the direction of canceling prying, etc. to stabilize the movement of the optical head. A counter balance is provided on the bottom surface of the optical head (including the carriage) so that the center of gravity of the optical head (the carriage) and the center of the drive force generation axis and the center of the guide axis are approximately aligned to balance the optical head, and the information from the optical head on the optical disc It is to stabilize writing and reading.

[0007]

By the way, theoretically considering the factors that hinder the stable movement of this kind of carriage,
As shown in FIG. 6, two parallel guide shafts 100, 10
If a driving force F is applied to the carriage 102 movably arranged between 0s and the carriage 102 is moved in the direction of arrow A, by any reason (for example, friction imbalance of the guide member 100).
When a rotational force in the direction of arrow L acts on the carriage 102 as a disturbance, a component force F1 of the driving force F is generated and acts in the rotational direction. As a result, the driving force F moves in the moving direction (N direction) of the carriage 102. The inconvenience of not working effectively occurs.

Therefore, in order to realize the ideal stable movement of the carriage, it is necessary to set the working efficiency of the driving force F to 100%, which can be said to be a fundamental solution for driving this kind of carriage.

However, the above-mentioned Japanese Patent Laid-Open No. 5-2748.
The technique disclosed in Japanese Patent Laid-Open No. 21 and Japanese Patent Application Laid-Open No. 5-151580 is a coping therapy measure that focuses on only friction reduction, that is, a guide shaft is constantly rotated or vibrated by a drive motor. Not only is insufficient, but there is a concern that the function of the device may be deteriorated due to the vibration.

Further, the techniques disclosed in JP-A-3-194733, JP-A-3-1375, JP-A-4-335213, and JP-A-3-76030 are perpendicular to the moving direction of the carriage. This is only the technical idea of making the center of gravity of the optical head (including the carriage) in the plane coincide with the center of the drive center axis and the center of the guide axis, and these have not yet reached a fundamental solution.

That is, as shown in FIG. 6, the driving force F does not act on the rear end of the carriage, and the driving coil of the linear motor is integrally mounted on the side portion of the carriage. Even if it is between the front end and the rear end of the carriage, if there is a gap between the position where the driving force acts and the leading end surface in the moving direction of the carriage, the efficiency of the driving force will decrease due to the above-mentioned component force generation. The inevitable inconvenience still exists.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a carriage drive mechanism capable of ensuring stable carriage movement while maintaining efficient transmission of drive force.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is based on the concept of applying a driving force to a position where there is no room for component force to be generated even if a disturbance acts on the carriage. In a carriage drive mechanism in which a carriage is supported by a guide member so as to be movable in the longitudinal direction of the guide member and is moved by a drive means, the carriage is moved to the center of gravity of the entire carriage at the front end surface portion in the moving direction of the carriage. The driving force of the driving means is applied so that the driving means can be pulled and moved.

The driving means can be composed of a driving source and an arm having a pressing portion which is connected to the driving source so as to be able to transmit the driving force and which abuts on the center of gravity. It can be formed in a bifurcated shape corresponding to the center of gravity of both end surface portions of the carriage.

Further, the drive source may be a linear motor which moves along the longitudinal direction of the guide member. As another example of the drive source, a rack gear that is composed of a rotary motor and a gear train that meshes with the rotary motor and that meshes with the gear train may be formed along the longitudinal direction of the arm of the guide member. Good.

[0016]

In the optical disk device, when an access command signal is sent to the carriage mechanism, a voltage is applied to the driving source of the driving means to generate a driving force. The driving force is exerted via the arm at one point in a concentrated manner so as to pull the carriage in the moving direction at the position of the center of gravity of the entire carriage at the front end surface portion in the moving direction of the carriage. Therefore, even if disturbance occurs on the downstream side of the driving force, there is no room for component force, and the entire driving force always works in the moving direction of the carriage.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention (application example to an optical disk device) will be described below with reference to FIGS.

As shown in FIG. 1, the carriage drive mechanism 2 shown in this embodiment has two parallel guide members 4 and the guide members 4 and 4 which are fitted and inserted in the longitudinal direction (of an optical disk (not shown)). And a drive means 8 for moving the carriage 6 arranged so as to be movable in the radial direction = arrow A, T directions).

The carriage 6 is a carriage base 10.
And the optical head 1 mounted on the carriage base 10.
2 and. The driving means 8 is the guide member 4
A linear motor 14 as a drive source that moves in the longitudinal direction of the carriage 6 and an arm 16 that is connected to the linear motor 14 and applies a driving force to the carriage 6.

The linear motor 14 includes a drive coil 18 as a moving body, a magnet 20 as a track, and a yoke 2.
2 and. On the other hand, the arm 16 is formed in a bifurcated shape corresponding to the bidirectional operability (access operation, tracking operation) of the carriage 6, and is fixed to the bifurcated arm bodies 24 and 26 and the drive coil 18. And a connecting portion 28. Each arm body 24,
At the tip of 26, a driving force corresponding to the center of gravity G of the carriage 6 on both side surfaces 10a, 10b (XY coordinate plane shown in FIG. 2) of the carriage base 10 perpendicular to the moving direction (A, T). Pressing portions 30 and 32 for directly applying
Are formed.

Depressing portions 30, 32 of the arm bodies 24, 26
The contact surfaces on which the
0a, 10b may be formed internally, but in order to correspond to the modification of the existing carriage mechanism, in this example, as shown in FIG. 3, the contact surface 34a including the center of gravity position G,
An additional configuration is adopted in which the side wall U-shaped brackets 34 and 36 having 36a are fixed to both side surfaces 10a and 10b.

As shown in FIG. 3, when an access command signal is issued to the carriage 6, a voltage is applied to the linear motor 14 under the control of a control unit (not shown), and the movable side of the linear motor 14 is accessed. Move in the direction (direction of arrow A). In this case, the pressing portion 3 of the arm body 24
0 comes into contact with the contact surface 34a of the bracket 34 at its center of gravity position G, whereby the moving force (driving force) of the linear motor 14 is at a single point at the center of gravity position G at the tip end surface portion in the moving direction of the carriage 6. It will be granted intensively. The same applies to the tracking operation. Here, the pressing portions 30, 32 of the arm bodies 24, 26
Has a smooth convex surface for making point contact with the position G of the center of gravity. Further, between the arm bodies 24 and 26 and the side surfaces 10a and 10b of the carriage base 10,
The gaps d are set so that when the carriage 6 moves in any one direction, the other drive configuration does not affect the movement.

As shown in FIG. 4, the driving force of the driving means 8 is applied to the center of gravity G at the tip end surface portion of the carriage 6 in the moving direction so that the driving force of the driving means 8 is concentrated to act as a traction. In addition, even if the rotational force M is generated due to the disturbance, they are all located on the downstream side of the driving force F, and there is no room for these to affect the driving force F.

Therefore, the entire driving force F always acts in the moving direction of the carriage 6, whereby the carriage 6 can be stably moved.

Next, FIG. 5 shows another embodiment, showing another example of the driving means 8.

The drive means 40 of the carriage drive mechanism 38 shown in this example is composed of a drive source 42 having a gear structure and an arm 44. The drive source 42 is a rotary motor 46.
And a gear train 48 driven by the rotary motor 46. The arm 44 is composed of arm bodies 24 and 26 and a rack gear 50 integrally fixed along the longitudinal direction of the guide member 4. . Upon receiving an operation signal such as an access signal, the rotary motor 46 rotates, and the rack gear 50 moves in the longitudinal direction of the guide member 4 via the gear train 48. The moving function of the carriage 6 is the same as the above example.

In each of the above examples, each component is shown in a specific shape. However, the present invention is not limited to this. It can be appropriately changed within a range satisfying the function.

[0028]

As described above, according to the present invention, even if a disturbance due to friction imbalance or the like unexpectedly acts on the carriage, the entire driving force is effective in the moving direction of the carriage without being affected by the disturbance. Therefore, stable movement of the carriage can be obtained.

[Brief description of drawings]

FIG. 1 is a partially omitted schematic perspective view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a center of gravity of the entire carriage in FIG.

FIG. 3 is an explanatory view showing an engagement state of an arm with respect to a carriage in FIG. 1 with a central portion omitted.

FIG. 4 is an explanatory diagram showing a stable movement state of a carriage in FIG.

FIG. 5 is a partially omitted schematic perspective view showing another embodiment.

FIG. 6 is an explanatory diagram showing an unstable movement state of a carriage in a conventional example.

[Explanation of symbols]

 4 Guide Member 6 Carriage 8 and 40 Drive Means 14 Linear Motor (Drive Source) 16,44 Arms 30 and 32 Pushing Unit 42 Drive Source 46 Rotating Motor 48 Gear Train 50 Rack Gear F Drive Force G Center of Gravity Position

Claims (5)

[Claims] 1. A carriage drive mechanism in which a carriage is supported by two guide members that are installed in parallel and is movably arranged in the longitudinal direction of the guide members, and is moved by a drive means. The driving force of the driving means is applied to the position of the center of gravity of the entire carriage in the tip end surface portion in the moving direction of
A carriage drive mechanism characterized by being pulled and moved. 2. The driving means comprises a driving source and an arm having a pressing portion which is connected to the driving source so as to transmit a driving force and which abuts on the center of gravity. The carriage drive mechanism according to claim 1. 3. The arm is formed in a bifurcated shape so as to correspond to the center of gravity of both end surface portions in the moving direction of the carriage,
The carriage drive mechanism according to claim 2, wherein the pressing portion is formed on each of them. 4. The carriage drive mechanism according to claim 2, wherein the drive source is a linear motor that is installed and moves along the longitudinal direction of the guide member. 5. The drive source comprises a rotary motor and a gear train rotationally driven by the rotary motor, and a rack gear meshing with the gear train is formed in the arm along the longitudinal direction of the guide member. The carriage drive mechanism according to claim 2, wherein the carriage drive mechanism is provided.