JP2002304860A - Transmission mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission mechanism in which a phase shift of teeth of two racks is prevented. SOLUTION: This transmission mechanism 7 is provided with a double gear 12, a 1st rack 18, a 2nd rack 21, and stoppers 16 and 24. The 1st rack 18 is fixed to an optical pickup 3 and the 2nd rack is freely moved back and forth relative to the 1st rack 18. Then a spring 15 is interposed between the 1st rack 18 and the 2nd rack 21 and this spring 15 energizes the 2nd rack 21 backward so as to allow the teeth of the 1st rack 18 and the teeth of the 2nd rack 21 to clamp teeth of a small gear of the double gear 12. In this state, the stopper 16 is apart from the stopper 24 by a half the pitch of the 1st rack 18. When a load is exerted against the spring 15, the stoppers 16, 26 are pressed into contact with each other to prevent the 2nd rack 21 from moving forward.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission mechanism provided in a pickup moving mechanism for linearly moving a pickup.

[0002]

2. Description of the Related Art In a disk reproducing apparatus, a CD or MD is used.
A pickup for reading the recorded contents of the disk, etc., is provided so as to be linearly movable in the radial direction of the disk. Such a disk reproducing apparatus includes a pickup moving mechanism for moving the pickup, and the pickup moving mechanism includes a motor as a driving source, and a transmission mechanism for transmitting the power of the motor to directly move the pickup. I have. As such a transmission mechanism, there is a transmission mechanism having a double rack mechanism composed of two racks, and a transmission mechanism having the double rack mechanism is shown in FIG.

As shown in FIG. 5, a transmission mechanism 100 includes a pinion 101 rotated by the power of a motor (not shown), a main rack 102 fixed to a pickup (not shown),
Secondary rack 103 movable with respect to main rack 102
And a spring 104 interposed between the main rack 102 and the sub rack 103. Teeth 101 of pinion 101
“a” is elastically held between the teeth 102 a of the main rack 102 and the teeth 103 a of the sub rack 103 by the urging force of the spring 104. The teeth of the pinion 101 are the main rack 10
There is an advantage that the backlash between the pinion 101 and the main rack 102 and the sub rack 103 is reduced by being elastically sandwiched between the second tooth and the sub rack 103.

[0004]

However, tooth drop between the pinion 101 and the main rack 102 and the sub rack 103 occurs due to a drop or an impact, thereby causing a phase shift between the main rack 102 and the sub rack 103. May happen.

[0005] Therefore, an object of the present invention is to prevent a phase shift between teeth of two racks.

[0006]

According to a first aspect of the present invention, there is provided a transmission mechanism for transmitting the power of a motor to a linear movement of a pickup, the transmission mechanism being arranged in a moving direction of the pickup. A first rack fixed to the pickup, a second rack arranged in the movement direction of the pickup, and movable in the movement direction of the pickup with respect to the first rack; A rotating gear that meshes with one rack and the second rack, and biasing means that biases the second rack so as to sandwich the teeth of the rotating gear between the teeth of the first rack and the teeth of the second rack. Moving range regulating means for regulating a moving range of the second rack when the second rack moves in a direction opposing the urging means. .

According to a second aspect of the present invention, in the transmission mechanism of the first aspect, the moving range restricting means restricts a moving range of the second rack to less than half a pitch of the first rack. And

According to a third aspect of the present invention, in the transmission mechanism according to the first or second aspect, the movement range restricting means includes a first stopper provided on the second rack and a movement locus of the first stopper. A second stopper fixed to the first stopper and disposed in a direction opposite to the urging means from the first stopper,
In a state where the teeth of the rotary gear are held between the teeth of the first rack and the teeth of the second rack, the interval between the first stopper and the second stopper is half the pitch of the first rack. It is characterized as follows.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, specific embodiments of a transmission mechanism according to the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated example. The transmission mechanism according to the present invention is provided in, for example, a reproducing unit for reproducing recorded contents of a disk.

The reproduction unit will be described. As shown in FIG. 1, the reproducing unit 1 includes a reproducing unit chassis 5, and the reproducing unit chassis 5 is provided with various members and mechanisms to configure the reproducing unit 1. That is, the reproduction unit chassis 5 has a motor 2 for rotating a turntable 6 for holding the center of the disc, and an optical pickup for focusing on the disc held on the turntable 6 and reading the recorded contents (information) of the disc. 3 and a pickup moving mechanism 4 for moving the optical pickup 3 in the radial direction of the disk held on the turntable 6.

The pickup moving mechanism 4 includes a motor 9 fixed to the reproducing unit chassis 5 and a motor 9.
And a guide 8, 8 for supporting the optical pickup 3 movably in the radial direction of the disk.
And

The guides 8, 8 are substantially straight rods,
They extend parallel to each other and are fixed to the reproduction unit chassis 5. And the optical pickup 3
Are slidably mounted on the guides 8,8. This allows the optical pickup 3 to move linearly in the radial direction of the disk held on the turntable 6. In the figure, the direction of the arrow a indicates the direction of the optical pickup 3.
Is the direction approaching the motor 2 (toward the center of the disk), and the direction of the arrow b indicates that the optical pickup 3 is
Direction away from the center of the disc (away from the center of the disc)
Hereinafter, the description will be made with the a direction as the front and the b direction as the rear.

FIG. 2 is an enlarged view of the transmission mechanism 7, and FIG. 3 is an exploded view of the transmission mechanism 7. FIG.
As shown in FIG. 3, the transmission mechanism 7 includes a gear 10, a two-stage gear 11, a two-stage gear (rotating gear) 12, a first rack member 13, a second rack member 14, and a spring 15 ( Biasing means) and a stopper 16 (second stopper).

The gear 10 is fixed to the drive shaft of the motor 9 and meshes with the large gear of the two-stage gear 11. The small gear of the second gear 11 meshes with the large gear of the second gear 12. The gear 10, the two-stage gear 11 and the two-stage gear 12 are rotated by the power of the motor 9.

The first rack member 13 is fixed to the optical pickup 3 by screws 17,17. On the side of the first rack member 13, a first rack 18 in which a plurality of teeth are arranged in a moving direction (front-back direction) of the optical pickup 3 is formed. Further, a stopper 19 is formed at an intermediate portion of the first rack member 13, and the stopper 1
A spring hook 19 a for hooking one end of the spring 15 is formed at the front end of the spring 9. Further, the first rack member 1
In 3, a guide groove 20 parallel to the moving direction of the optical pickup 3 is formed.

The second rack member 14 is used for the first rack member 1.
3, and is movable back and forth with respect to the first rack member 13 and the optical pickup 3 by being guided by the guide groove 20. On a side portion of the second rack member 14, a second rack 21 in which a plurality of teeth are arranged in a moving direction (front-back direction) of the optical pickup 3 is formed.
The second rack 21 has substantially the same shape as the first rack 18. That is, the number of teeth of the second rack 21 is the same as the number of teeth of the first rack 18, and the pitch of the second rack 21 is
It is the same as the pitch of the first rack 18.

A guide hole 22 is formed in the second rack member 14. The stopper 19 is fitted in the guide hole 22 so as to be slidable in the front-rear direction. A spring hook 23 for hooking the other end of the spring 15 is formed on a rear surface in the guide hole 22.
And the spring 15 is disposed in the guide hole 22,
One end of the spring 15 is hooked on a spring hook 19 a, and the other end of the spring 15 is hooked on a spring hook 23. This spring 15 is compressed by a spring hook 19
a on the first rack member 13 and the second rack member 1
4 is pushed rearward. In addition, since the stopper 19 abuts on the front surface in the guide hole 22, the second rack member 14 is prevented from moving backward with respect to the first rack member 13.

In the second rack member 14, a stopper 24 (first stopper) protrudes from the side opposite to the side on which the second rack 21 is formed. Fixed. This stopper 2
The stopper 4 moves back and forth in accordance with the movement of the second rack member 14, and the stopper 16 is arranged on the movement locus of the stopper 24. Further, the stopper 16 is arranged in front of the stopper 24 and is fixed to the optical pickup 3. Then, the second rack member 14 is
5 when moving forward against the biasing force of
The fourth rack member 14 is prevented from moving forward due to the contact of the stopper 4 with the stopper 16 (see FIG. 4).

First rack member 1 constructed as described above
The third and second rack members 14 are connected to the two-stage gear 12. That is, the small gear of the two-stage gear 12 is
And the second rack 21. In a state where the small gear of the two-stage gear 12 is engaged with the first rack 18 and the second rack 21, the second rack member 14 is urged rearward by the spring 15, so that the small gear of the two-stage gear 12 is The teeth are sandwiched between the teeth of the first rack 18 and the teeth of the second rack 21. In this state, the stopper 24 is separated from the stopper 16, and the distance between the stopper 16 and the stopper 24 is less than half the pitch of the first rack 18. Further, in this state, the stopper 19 is separated from the front surface in the guide hole 22. In the present embodiment, when the small gear of the two-stage gear 12 is engaged with the first rack 18 and the second rack 21, the distance between the stopper 16 and the stopper 24 is equal to the pitch of the first rack 18. About half.

The transmission mechanism 7 configured as described above transmits the power of the motor 9 to linearly move the optical pickup 3 back and forth. That is, the gear 1 is driven by the power of the motor 9.
1, the two-stage gear 12 and the two-stage gear 13 rotate, and the optical pickup 3 moves back and forth together with the first rack member 13 and the second rack member 14. The teeth of the small gear of the two-stage gear 12 are elastically sandwiched between the teeth of the first rack 18 and the teeth of the second rack 21, so that the small gear of the two-stage gear 12, the first rack 18, and the second Backlash with the rack 21 is reduced.

When a load against the urging force of the spring 15 acts on the second rack member 14 due to, for example, an impact applied to the reproducing unit 1, the second rack member 14 moves forward. However, as shown in FIG.
The contact between the stopper 6 and the stopper 24 prevents the second rack member 14 from moving forward. here,
The amount of forward movement of the second rack member 14 from the state where the small gear of the two-stage gear 12 is engaged with the first rack 18 and the second rack 21 to the state where the stopper 16 and the stopper 24 are in contact is: It is restricted to less than half the pitch of the first rack 18. Therefore, even if the small gear of the two-stage gear 12 floats from the first rack 18 and the second rack 21 due to a load such as an impact, the stopper 16
In addition, since the movement range of the second rack member 14 is regulated by the stopper 24 and the second rack 21,
Does not move for one pitch. Therefore, the two-stage gear 12
Does not fly out of the first rack 18 and the second rack 21, and further, there is no phase shift between the teeth of the first rack 18 and the second rack 21. Here, the phase shift between the first rack 18 and the second rack 21 means that the first rack 18 is shifted by one pitch or more with respect to the second rack 21 and the two-stage gear 12
And the first rack 18 and the second rack 21 mesh with teeth different from the teeth to be meshed.

By the way, as a method of preventing tooth jump between the pinion and the two racks, there are methods such as increasing the size of the pinion module and improving the rigidity of the rack. There is a problem that the structure is increased and the manufacturing cost is increased. However, in the present invention, the structure in which the stopper 16 and the stopper 24 are provided eliminates tooth skipping between the small gear of the two-stage gear 12 and the first rack 18 and the second rack 21.
Even if the size of the transmission mechanism 7 is not increased, the problem of tooth skipping is solved while the manufacturing cost of the transmission mechanism 7 is suppressed.

The present invention is not limited to the embodiments described above, and various modifications can be made.

For example, in the above-described embodiment, the stopper 16 is provided on the optical pickup 3, but the stopper 16 may be provided on the first rack member 13 or may be provided on another member. good. That is, the stopper 16
Need only be fixed to the first rack member 13. In the above embodiment, the compressed spring 15
Although the second rack member 14 is urged forward by the above, the second rack member 14 may be urged forward by a tension spring, or may be an elastic member having the same function. .

[0025]

As described above, according to the first aspect of the present invention, when the second rack moves in the direction opposing the teeth of the first rack and the urging means, the range of movement of the second rack. Is restricted, the second rack does not largely move in the direction against the urging means. Therefore, the rotating gear does not jump from the first rack and the second rack, and there is no phase shift between the teeth of the first rack and the teeth of the second rack.

According to the second aspect of the present invention, the rotary gear does not jump from the first rack and the second rack.

According to the third aspect of the present invention, when the second rack moves in a direction against the urging means from a state where the teeth of the rotary gear are held between the teeth of the first rack and the teeth of the second rack. In addition, when the first stopper comes into contact with the second stopper, the second rack is prevented from moving in the direction opposed to the urging means, and the amount of movement is half the pitch of the first rack. Therefore, the rotating gear does not jump from the first rack and the second rack. Furthermore, it is not necessary to increase the size of the module of the rotating gear or the rigidity of the first rack and the second rack, so that the size of the transmission mechanism can be reduced, and the manufacturing cost of the transmission mechanism can be reduced, Tooth jump of the rotary gear from the second rack is prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a specific mode of a reproducing unit including a transmission mechanism according to the present invention.

FIG. 2 is an enlarged perspective view of the transmission mechanism.

FIG. 3 is an exploded view of the transmission mechanism.

FIG. 4 is an enlarged perspective view of the transmission mechanism.

FIG. 5 is a plan view showing a conventional transmission mechanism.

[Explanation of symbols]

Reference Signs List 3 optical pickup (pickup) 7 transmission mechanism 9 motor 12 two-stage gear (rotating gear) 13 spring (biasing means) 13 first rack member 14 second rack member 15 spring (biasing means) 16 stopper (second stopper). 18 First rack 21 Second rack 24 Stopper (first stopper, which constitutes a movement range restricting means.)

Claims (3)

[Claims] 1. A transmission mechanism for transmitting the power of a motor to a linear movement of a pickup, wherein the first rack is arranged in the movement direction of the pickup and fixed to the pickup, and the first rack is arranged in the movement direction of the pickup. A second rack movable in the movement direction of the pickup with respect to the first rack; a rotating gear that rotates by the power of the motor and meshes with the first rack and the second rack; Urging means for urging the second rack so that the teeth of the rotary gear are sandwiched between the teeth of the second rack; and the urging means when the second rack moves in a direction against the urging means. A transmission range regulating means for regulating a range of movement of the second rack. 2. The transmission mechanism according to claim 1, wherein said moving range restricting means restricts a moving range of said second rack to a half or less of a pitch of said first rack. 3. The moving range restricting means is fixed on a first stopper provided on the second rack, and on a movement locus of the first stopper, and a direction opposing the urging means from the first stopper. A distance between the first stopper and the second stopper in a state where the teeth of the rotating gear are held between the teeth of the first rack and the teeth of the second rack. 3. The transmission mechanism according to claim 1, wherein the length of the transmission mechanism is equal to or less than half the pitch of the first rack. 4.