JP3650293B2 - Optical pickup transport mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transfer mechanism for transferring an optical pickup mounted on a carriage in the radial direction of a disk.
[0002]
[Prior art]
When recording and / or reproducing information on a disc such as a CD (compact disc) or MD (mini disc) using an optical pickup, it is necessary to transport the optical pickup in the radial direction of the disc. As such an optical pickup transport mechanism, the one shown in FIG. 4 is known.
[0003]
In FIG. 4, reference numeral 1 denotes a carriage on which an optical pickup 2 is mounted. The carriage 1 is disposed between the guide shaft 3 and the screw shaft 4. The guide shaft 3 and the screw shaft 4 are opposed to each other in parallel. The screw shaft 4 is driven to rotate in both forward and reverse directions by a thread motor (not shown). Receiving portions 1 a and 1 b are projected from both side surfaces of the carriage 1, one receiving portion 1 a is in contact with the peripheral surface of the guide shaft 3, and the other receiving portion 1 b is inserted through the screw shaft 4. A leaf spring 5 is screwed to the carriage 1, and the leaf spring 5 extends in a direction perpendicular to the axis of the screw shaft 4. A synthetic resin half nut 6 is attached to the tip of the leaf spring 5, and the toothed portion of the half nut 6 is pressed against the threaded portion of the screw shaft 4 by the elasticity of the leaf spring 5.
[0004]
When the screw shaft 4 rotates in either the forward or reverse direction in the optical pickup transfer mechanism schematically configured as described above, this rotational force is converted into a linear motion by the teeth of the half nut 6 and transmitted to the carriage 1. Therefore, the carriage 1 moves along the axial direction of the guide shaft 3 and the screw shaft 4. As a result, the optical pickup 2 mounted on the carriage 1 is transferred in the radial direction (inner or outer periphery) of the disc, and information recording and / or reproducing operations are performed on the disc.
[0005]
[Problems to be solved by the invention]
By the way, in an in-vehicle CD player or MD player equipped with this type of transfer mechanism, the optical pickup is generally positioned on the inner peripheral side of the disc in an initial state before being assembled to the vehicle, and the optical pickup is used during use. A method of transferring from the inner peripheral side to the outer peripheral side is adopted. For this reason, a large impact force is applied from the inside to the outside along the axial direction of the screw shaft, especially when the product is dropped or a large impact is applied to the carriage during transportation before assembling to the vehicle. Sometimes, the teeth of the half nut come off from the threaded portion of the screw shaft against the elasticity of the leaf spring, and the carriage carrying the optical pickup collides with the chassis etc. from the inner periphery to the outer periphery, and the impact force As a result, the carriage and the optical pickup were damaged.
[0006]
In addition, when used after being assembled in a vehicle, the optical pickup moves within the signal range recorded on the innermost and outermost circumferences of the disc. Due to the above factors, the optical pickup may not be able to read these signals. In this case, the innermost position of the disc is detected by using a limit switch, so there is no concern that the optical pickup will exceed the innermost position. since is possible to arrange the limit switch on the outer circumferential position is difficult, there is the optical pickup may run away without read signal outermost. When the optical pickup runs away in the outer peripheral direction and hits the chassis or the like in this way, the tooth portion of the half nut receiving a strong urging force from the leaf spring bites into the screw portion of the screw shaft, There has been a problem that the carriage cannot be returned to the inner circumferential direction by reverse rotation.
[0007]
[Means for Solving the Problems]
In the present invention, a cantilever-like elastic arm is extended along the axial direction of the screw shaft with the inner peripheral side of the disk as a fixed end, and a tooth portion is provided on the free end side of the elastic arm. With this configuration, when an external force from the inside to the outside acts on the optical pickup, a force in the direction of biting the screw portion of the screw shaft is applied to the tooth portion. It can be stably held on the inner peripheral side, and damage to the carriage and the optical pickup can be reliably prevented. On the other hand, when an external force from outside to inside acts on the optical pickup, a force in the direction of climbing the screw shaft thread is applied to the teeth, so when the optical pickup runs away from the outermost circumference of the disc during use. The tooth portion can be prevented from biting into the screw portion of the screw shaft, and the carriage can be reliably returned to the inner circumferential direction.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the optical pickup transport mechanism according to the present invention, a carriage on which the optical pickup is mounted, a screw shaft that rotates in both forward and reverse directions using a motor as a driving source, and a cantilever-like support on the carriage, A power conversion member having a tooth portion elastically biased in a direction to mesh with the screw shaft, and the optical pickup transport mechanism in which the optical pickup moves in the radial direction of the disk as the screw shaft rotates. The power conversion member includes a synthetic resin toothed plate having the toothed portion and a leaf spring that elastically biases the toothed portion in a direction in pressure contact with the screw shaft, and the toothed plate includes an inner portion of the disk. Rutotomoni an elastic arm extending in the axial direction of the screw shaft the peripheral side as the fixed end, prior to the free end of the elastic arm Teeth provided, said plate in the spring forms a pressing piece extending along the elastic arm of the toothed plate, and each of said plate spring and said toothed plate extending in the axial direction of the screw shaft at both ends Is provided with a base fixed to the carriage, and the elastic arm and the pressing piece are extended in parallel with the base from one end side to the other end side of each of the base parts, and the pressing piece It was set as the structure which carries out uneven | corrugated engagement of a free end part and the back surface side of the said tooth part .
[0009]
With this configuration, a reverse moment centering on the fixed end of the elastic arm is generated in the tooth portion according to the direction of the external force acting on the optical pickup. Can be stably held on the inner peripheral side, and the carriage can be reliably returned to the inner peripheral direction even when the optical pickup runs out of control beyond the outermost outer periphery of the disk during use.
[0010]
In the above configuration, the elastic arm and the tooth portion may be formed on the leaf spring fixed to the carriage in a cantilever shape to form a power conversion member. However, the elastic arm and the tooth portion are integrated with a toothed plate made of a synthetic resin material. It is preferable that a plate spring for elastically urging the toothed portion of the toothed plate is fixed to the carriage, and the power conversion member is constituted by the two members of the toothed plate and the plate spring. In this case, if a pressing piece extending along the elastic arm of the toothed plate is formed on the leaf spring, the spring span of the leaf spring becomes longer without sacrificing space, so the variation in the pressure contact force of the tooth portion against the screw shaft Can be suppressed.
[0011]
【Example】
The embodiment will be described with reference to the drawings. FIG. 1 is a structural view of the transfer mechanism of the optical pickup according to the embodiment as viewed from the back side, FIG. 2 is an explanatory view showing the meshing state of the tooth portion and the screw shaft, FIG. FIG. 3 is an exploded perspective view of a toothed plate and a leaf spring.
[0012]
In these drawings, reference numeral 10 denotes a carriage on which an optical pickup 11 is mounted. The carriage 10 moves in the directions of arrows A and B in the opening 14 a of the chassis 14 along the axial direction of the guide shaft 12 and the screw shaft 13. . The guide shaft 12 and the screw shaft 13 are opposed to each other in parallel with the chassis 14, and one end of the screw shaft 14 is connected to the rotating shaft of the thread motor 16 through the gear train 15. A spindle motor 17 and a limit switch 18 are attached to the chassis 14, and the spindle motor 17 and the limit switch 18 are located on one end side of the opening 14a. A turntable 19 is attached to the rotating shaft of the spindle motor 17, and a disk (not shown) such as a CD or MD is centered on the turntable 19 and driven to rotate. That is, in FIG. 1, an arrow A indicates the inner circumferential direction of the disk, and an arrow B indicates the outer circumferential direction of the disk. The limit switch 18 is operated by the carriage 10, and the inner peripheral position of the optical pickup 11 is detected by an operation signal output from the limit switch 18.
[0013]
Receiving portions 10 a and 10 b project from both side surfaces of the carriage 10, one receiving portion 10 a abuts on the peripheral surface of the guide shaft 12, and the other receiving portion 10 b is inserted through the screw shaft 13. A toothed plate 20 and a leaf spring 21 are fixed to the back surface of the carriage 10 using a pair of screws 22, and the rotation of the screw shaft 13 is converted into a linear motion by the toothed plate 20 and the leaf spring 21. A power conversion member is configured.
[0014]
As shown in FIG. 3, the toothed plate 20 is integrally formed of a synthetic resin material, and a base portion 20a fixed to the carriage 10 and an elastic arm 20b extending in parallel from one end side to the other end side of the base portion 20a. And a tooth portion 20c protruding from the tip of the elastic arm 20b. A large diameter screw hole 20d and a small diameter positioning hole 20e are respectively formed in the base portion 20a, and a slit 20f and a pin 20g are formed in the elastic arm 20b. Further, the leaf spring 21 is formed by forming a thin metal plate, such as stainless steel, which is rich in spring properties, and a base portion 21a fixed to the carriage 10 and a pressing piece 21b extending in parallel from one end side to the other end side of the base portion 21a. Is formed and has substantially the same planar shape as the toothed plate 20. The base portion 21a has a pair of large-diameter screw holes 21c and small-diameter positioning holes 21d, and a stepped portion at the tip of the pressing piece 21b has a hole 21e inserted into the pin 20g of the toothed plate 20. Is drilled.
[0015]
The toothed plate 20 and the leaf spring 21 are fixed in a state of being overlapped on the back surface of the carriage 10 by inserting and tightening a pair of screws 22 into the screw holes 20d and 21c, and the carriage 20 is positioned by the positioning holes 20e and 21d. 10 is accurately positioned. As shown in FIGS. 1 and 2, in such an attached state, the elastic arm 20b of the toothed plate 20 extends in the axial direction of the screw shaft 13 from the inner peripheral side of the disk with the base portion 20a as a fixed end, and the elastic arm 20b The tooth portion 20c formed at the tip (free end) is located on the outer peripheral side of the disk. Further, the pressing piece 21b of the leaf spring 21 also extends in the axial direction of the screw shaft 13 from the inner peripheral side of the disk with the base portion 21a as a fixed end, and the tooth portion 20c becomes the threaded portion of the screw shaft 13 by the elastic force of the pressing piece 21b. Is in pressure contact.
[0016]
In the transfer mechanism of the optical pickup thus schematically configured, when the screw shaft 13 rotates in either the forward or reverse direction using the thread motor 16 as a driving source, the rotational force is linearly moved by the tooth portion 20c of the toothed plate 20. Therefore, the carriage 10 moves along the axial direction of the guide shaft 12 and the screw shaft 13. As a result, the optical pickup 11 mounted on the carriage 10 is transferred in the radial direction of the disk (in the direction of arrows AB in FIG. 1), and information recording and / or reproducing operations are performed on the disk.
[0017]
In the above embodiment, when an external force in the direction of arrow B in FIG. 1 is applied to the carriage 10 on which the optical pickup 11 is mounted, the free end of the elastic arm 20b is indicated by Mb in FIG. Moment is generated, and a force in the direction of biting the screw portion of the screw shaft 13 is applied to the tooth portion 20c. Accordingly, even when a drop impact force is applied during transportation before assembling the product to the vehicle, the tooth portion 20c is difficult to ride on the screw portion of the screw shaft 13 against the impact force in the outer peripheral direction. The optical pickup 11 is not moved and damaged from the inner peripheral side to the outer peripheral side, and the optical pickup 11 can be stably held on the inner peripheral side. On the other hand, when an external force in the direction of arrow A in FIG. 1 is applied to the carriage 10, a moment as indicated by Ma in FIG. A force in the direction of climbing the threaded portion of the shaft 13 is applied. Therefore, even when the optical pickup 11 runs away beyond the outermost periphery of the disk for some reason during use, that is, when an external force in the inner peripheral direction acts on the carriage 10 due to a reaction force from the stopper portion such as the chassis 14. The tooth portion 20c does not easily bite into the screw portion of the screw shaft 13, and the carriage 10 can be reliably returned to the inner circumferential direction by the reverse torque of the thread motor 16. Further, the tooth portion 20c is pressed against the screw shaft 13 by the elastic force of the pressing piece 21b formed on the leaf spring 21, and the pressing piece 21b extends along the axial direction of the screw shaft 13 in parallel with the elastic arm 20b. Therefore, the spring span of the leaf spring 21 becomes longer without sacrificing space, and variations in the pressure contact force of the tooth portion 20c against the screw shaft 13 can be suppressed.
[0018]
【The invention's effect】
The present invention is implemented in the form as described above, and has the following effects.
[0019]
If the cantilever-like elastic arm is extended along the axial direction of the screw shaft with the inner peripheral side of the disk as the fixed end, and the tooth portion that meshes with the screw shaft is provided on the free end side of this elastic arm, the optical pickup Depending on the direction of the external force acting, a reverse moment occurs around the fixed end of the elastic arm at the tooth part, so the optical pickup can be stably held on the inner circumference against a drop impact during transportation. In addition, the carriage can be surely returned to the inner circumferential direction when the optical pickup runs away from the outermost circumference of the disk during use.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an optical pickup transfer mechanism according to an embodiment as viewed from the back side.
FIG. 2 is an explanatory view showing a meshing state of a tooth portion and a screw shaft.
FIG. 3 is an exploded perspective view of a toothed plate and a leaf spring.
FIG. 4 is a configuration diagram illustrating a transfer mechanism of an optical pickup according to a conventional example.
[Explanation of symbols]
10 Carriage 11 Optical Pickup 13 Screw Shaft 14 Chassis 16 Thread Motor 17 Spindle Motor 18 Limit Switch 20 Toothed Plate 20a Base 20b Elastic Arm 20c Tooth 21 Plate Spring 21a Base 21b Pressing Piece

Claims (1)

A carriage equipped with an optical pickup, a screw shaft that rotates in both forward and reverse directions using a motor as a drive source, and a cantilever-like support supported on the carriage, and elastically biased in a direction that meshes with the screw shaft on its free end side A power conversion member having a toothed portion, wherein the optical pickup moves in the radial direction of the disk as the screw shaft rotates,
The power conversion member is composed of a synthetic resin toothed plate having the toothed portion and a leaf spring that elastically biases the toothed portion in a direction in pressure contact with the screw shaft . Rutotomoni an elastic arm extending in the axial direction of the screw shaft and the inner peripheral side as a fixed end, the teeth provided at the free end of the elastic arm, the said plate spring along the elastic arm of the toothed plate And a base portion that extends in the axial direction of the screw shaft is fixed to the toothed plate and the leaf spring, and both ends thereof are fixed to the carriage, and the elastic arm and the pressing piece The bases are extended in parallel with the bases from one end side to the other end side of the respective base portions, and the free end portions of the pressing pieces and the back side of the tooth portions are engaged with each other. Light pick -Up of the transport mechanism.

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