JP2003308665A - Head drive mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily adjust a backlash of a gear placed on a head drive path. <P>SOLUTION: Adjustment of a tightening position of an adjustment screw 60 screwed to a fixed plate 72 in a backlash adjustment unit 58 changes a compression amount of a leaf spring 78 to elevate/descend a movable plate 76 tightened to a movable base 70 via a machine screw 74 in response to the compression amount of the leaf spring 78. Thus, a reduction gear 56 is elevated/ descended from a fixed base 68 while being supported by the movable base 70 in response to the tightening position of the adjustment screw 60. Then the reduction gear 56 is elevated/descended from a drive gear and a follower gear by changing the height of the movable base 70 in response to the tightening position of the adjustment screw 60. In this case, the backlash among teeth of each gear is adjusted by changing the relative position of the drive gear meshing with a large diameter gear 56a and the relative position of the follower gear meshing with a small diameter gear 56b in the reduction gear 56. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head drive mechanism, and more particularly to a head drive mechanism configured to adjust the backlash of a gear provided in a mechanism for moving a head.

[0002]

2. Description of the Related Art For example, in a disc device in which a disc-shaped recording medium is mounted, an optical head for optically reading information recorded on the disc-shaped recording medium is provided so as to move in the disc radial direction. The drive mechanism that seeks the optical head in the disk radial direction includes, for example, a motor, a plurality of gears that reduce the rotation of the motor, and a lead screw that is rotationally driven through the plurality of gears.

The optical head has an engaging portion that engages with the lead screw, and seeks according to the amount and direction of rotation of the lead screw.

In the transmission mechanism configured to transmit the rotation of the motor through the plurality of gears, if the gears are not properly meshed with each other, the teeth may be meshed with each other or the teeth may be meshed with each other. The gaps between the teeth may become large and rotation transmission may not be performed smoothly, resulting in increased noise and vibration.

Therefore, in the gear mechanism, it is necessary to provide backlash (play between tooth surfaces) between the gears so that the gears can rotate without difficulty.

[0006]

However, in order to increase the seek speed of the optical head driven through the gear mechanism as described above, it is necessary to reduce the backlash between the gears to reduce noise and vibration. There is.

However, conventionally, the backlash is determined by, for example, the processing accuracy or the molding accuracy of the bearing member that holds each gear, so that the distance between the pair of gears cannot be adjusted.

Further, when the distance between the pair of gears is adjustable, the backlash between the gears can be adjusted.
If the backlash is made too small, the teeth of the gears will be meshed with each other and the load will increase. Therefore, conventionally, it has been difficult to adjust the backlash between the gears within a range where the load does not increase, and the backlash cannot be managed to an arbitrary value.

Therefore, an object of the present invention is to provide a head drive mechanism that solves the above problems.

[0010]

In order to solve the above problems, the present invention has the following features. The invention according to claim 1 is a head drive mechanism having a drive unit for moving a head for reading information on a recording medium, and a transmission mechanism for transmitting the rotational driving force of the drive unit to the head, wherein the transmission mechanism is the drive unit. A first gear to which the rotational driving force is input, a second gear to which the rotational driving force is transmitted via the first gear, and a third gear between the first gear and the second gear. Movably intervenes the third gear and the third gear as the first gear and the second gear.
And an adjusting portion that adjusts the meshing position with the gear, and by adjusting the mounting position of the third gear, it is possible to adjust the backlash between the gears to an arbitrary gap. Therefore, the meshing position of the third gear with the first gear and the second gear can be adjusted relatively easily, and the backlash between the gears can be adjusted to a value as small as possible within the range where the load does not increase.

According to the second aspect of the invention, the adjusting portion is
A fixed portion that supports the first gear and the second gear, a movable portion that is movably mounted on the fixed portion and that supports the third gear, and a relative position between the fixed portion and the movable portion are arbitrary positions. And an adjusting screw for moving the movable portion by the adjusting screw, the meshing position of the third gear with the first gear and the second gear can be adjusted relatively easily, and the load is reduced. The backlash between the gears can be adjusted to a value as small as possible without increasing.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of a disk device using a head drive mechanism according to the present invention. FIG. 2 is a plan view of the disk device. FIG. 3 is a plan view showing a state in which the tray 20 is pulled out to the disc exchange position. As shown in FIGS. 1 and 2, the disk device 11 is, for example, a CD-ROM drive device, and rotates a turntable 18 in a space formed between an upper cover (not shown) and a lower cover 16. It has a tray 20 that supports it freely. The turntable 18 has a clamp mechanism 23 at the center, which is fitted to the inner circumference of the disc 22 to clamp the disc 22. In addition, around the turntable 18, a disc storage portion 2 having a diameter larger than that of the disc is provided.
4 are formed.

Below the disc storage portion 24,
An optical head 26, which constitutes an optical head portion for reading information recorded on the disk 22 clamped by the clamp mechanism 23 of the turntable 18, is attached so as to be movable in the disk radial direction.

The optical head 26 is housed in the recess 24a of the disk housing 24, and the recess 24a is covered with an optical head cover 28 having an opening 28a in the range in which the objective lens 27 of the optical head 26 moves. Further, the front bezel 30 coupled to the front end of the tray 20 is provided with an eject button 32 at the center.

A disk motor 19 provided below the turntable 18 is rotationally driven to rotate the turntable 18.
And the disk 22 clamped by the clamp mechanism 23 of the turntable 18 rotates.

As shown in FIG. 3, the tray 20 has guide rails 4 mounted on both sides so as to be slidable in the front-rear direction.
When the eject button 32 provided on the front bezel 30 is pressed, the tray 20 is unlocked, and the tray 20 is unlocked.
Is slid in the direction A by manual operation and pulled out to the disc exchange position. Further, after the disc 22 is clamped to the turntable 18 of the tray 20 that has been pulled out to the disc exchange position, the operator pushes the front bezel 30 in the B direction to move the tray 20 in the B direction. It is locked at the disc mounting position shown in 2.

An optical head drive mechanism for moving the optical head 26 in the disk radial direction will be described below.
2 and 3, the optical head drive mechanism (head drive mechanism) 34 includes a pair of guide shafts 35 and 36 for guiding the moving direction of the optical head 26, a drive motor 37 for driving the optical head 26, and a drive motor. And a transmission mechanism 38 for transmitting the rotational driving force of 37 to the optical head 26. Further, bearing portions 26a to 26c, which are engaged with the pair of guide shafts 35 and 36 and are guided in the moving direction, project from both sides of the optical head 26. The transmission mechanism 38 is a gear mechanism 38 that reduces the rotation of the drive motor 37.
a and a lead screw 38b which is rotationally driven via a gear mechanism 38a. Then, the optical head 26
Has an engaging portion 26d that engages with the spiral groove of the lead screw 38b.

Therefore, the rotation of the drive motor 37 is transmitted to the lead screw 38b via the gear mechanism 38a, whereby the optical head 26 moves in the disk radial direction. FIG. 4 is an exploded perspective view showing the optical head 26 and the optical head cover 28.

As shown in FIG. 4, an optical head unit 46 that supports the optical head 26 movably in the disk radial direction is disposed below the optical head cover 28. The optical head unit 46 includes the turntable 18, the optical head 26, the guide rails 35 and 36.
And a sub-base 48 for holding them in parallel.

The optical head cover 28 includes the optical head 26.
Opening 28 corresponding to the range of movement of the objective lens 27 of
a and a circular hole 28b through which the turntable 18 is inserted
Have and. The sub-base 48 has an opening 48a within a range in which the optical head 26 moves, and a semicircular hole 48b into which the disc motor 19 is inserted. The optical head 26 is movably provided in the opening 48 a of the sub base 48, and the sub base 48 is attached to the lower surface of the tray 20.

The optical head 26 is guided so that the objective lens 27 moves at a position facing the opening 28a of the optical head cover 28. The optical head cover 28 is formed so as to cover the upper surface of the optical head 26 excluding the objective lens 27, and the opening 4 of the sub-base 48 is formed.
It also functions as a shield member that blocks electromagnetic waves while blocking 8a.

The structure of the optical head drive mechanism 34, which is the main part of the present invention, will now be described. FIG. 5 is a bottom view of the sub base 48 seen from the lower surface side. FIG. 6 is an enlarged cross-sectional view showing the optical head drive mechanism 34. Incidentally, FIG.
Then, the fixed base 68 described later is omitted.

As shown in FIGS. 5 and 6, in the optical head drive mechanism 34, the rotational driving force of the drive motor 37 attached to the lower surface of the sub-base 48 is transmitted to the optical head 26 via the transmission mechanism 38. Is configured. The gear mechanism 38a of the transmission mechanism 38 is interposed between the drive motor 37 and the lead screw 38b, and decelerates the rotational driving force of the drive motor 37 and transmits it to the lead screw 38b.

Further, the gear mechanism 38a includes a drive motor 37
Drive gear (first gear) 5 press-fitted into the rotary shaft 37a of the
2, a driven gear (second gear) 54 press-fitted into the end portion 38c of the lead screw 38b, and a reduction gear (third gear) 56 interposed between the drive gear 52 and the driven gear 54.
It consists of and.

The reduction gear 56 is supported by a backlash adjustment unit (adjustment section) 58, and the drive gear 52 is supported.
The meshing position between the driven gear 54 and the driven gear 54 is adjusted. The backlash adjustment base 58 is provided so as to raise and lower the reduction gear 56 by turning the adjustment screw 60. Therefore, the meshing position of the reduction gear 56, the drive gear 52, and the driven gear 54 is adjusted according to the screwing amount (rotational position) of the adjusting screw 60. As a result, the backlash between the gears is adjusted to be small within the range where the load does not increase.

The reduction gear 56 is rotatably supported by a shaft 62 inserted in a backlash adjusting unit 58, and a large diameter gear 56a meshing with the drive gear 52 and a small diameter gear 56b meshing with the driven gear 54 are integrated. It is molded. Therefore, the rotation of the rotation shaft 37a of the drive motor 37 is
The gear ratio (the number of teeth ratio) between the drive gear 52 and the large diameter gear 56a,
Also, the rotation speed is reduced to a speed corresponding to the reduction ratio determined by the gear ratio (teeth ratio) between the driven gear 54 and the small diameter gear 56b.

Reference numeral 66 is a rotational position detecting magnet,
The rotation position of the drive gear 52 is detected in cooperation with a hall element (not shown).

FIG. 7 is an enlarged side elevational sectional view showing the backlash adjusting unit 58. FIG. 8 is a front vertical sectional view showing the meshing relationship of the gears.

As shown in FIGS. 7 and 8, in the backlash adjustment unit 58, the position of the movable base 70 in the height direction is adjusted with respect to the fixed base (fixed portion) 68 fixed to the sub base 48. Is provided. The movable base (movable part) 70 is attached to a fixed plate 72 fixed to the upper surface of the fixed base 68 so as to be movable up and down.

The movable base 70 includes a gear accommodating recess 70a for accommodating the reduction gear 56 rotatably and a gear accommodating recess 70.
a pair of bearings 70b, 70c formed so as to surround a
And a protrusion 70 protruding above the bearings 70b and 70c.
d, 70e. The backlash adjustment unit 58 includes the fixed base 68, the movable base 70,
Between the movable plate 76 fixed to the upper surfaces of the protrusions 70d and 70e with screws 74, the adjusting screw 60 inserted into the movable plate 76 and screwed into the fixed plate 72, and between the movable plate 76 and the fixed plate 72. It is composed of an intervening leaf spring (biasing member) 78.

The leaf spring 78 abuts the lower surface of the movable plate 76 and biases it upward, and the amount of compression changes according to the distance between the movable plate 76 and the fixed plate 72. Therefore, the leaf spring 78 changes the compression amount of the leaf spring 78 by adjusting the tightening position of the adjusting screw 60 screwed into the fixed plate 72. And the movable plate 7
Since 6 is fastened to the movable base 70 via the screw 74, it is possible to move up and down according to the compression amount of the leaf spring 78.

That is, the reduction gear 56 includes the adjusting screw 60.
Depending on the tightening position of the movable base 70, the movable base 70 is moved up and down with respect to the fixed base 68.

9A and 9B are views showing the arrangement of the drive gear 52 and the driven gear 54. FIG. 9A is a plan view and FIG. 9B is a cross sectional view. As shown in FIGS. 9A and 9B, the drive gear 52 and the driven gear 54 arranged on both the left and right sides of the movable base 70 are driven to extend in the A and B directions, which are the moving directions of the optical head 26. The rotary shaft 37a of the motor 37 and the end portion 38c of the lead screw 38b are press-fitted. Further, the rotating shaft 37a and the end portion 38c are arranged in parallel at a position of a predetermined distance. As a result, the drive gear 52 and the driven gear 5
The distance from 4 is also fixed to a predetermined distance.

Therefore, the reduction gear 56 includes the adjusting screw 60.
By changing the height position of the movable base 70 in accordance with the tightening position of, the movable base 70 moves up and down with respect to the drive gear 52 and the driven gear 54. At that time, in the reduction gear 56, the relative position of the drive gear 52 meshing with the large diameter gear 56a and the relative position of the driven gear 54 meshing with the small diameter gear 56b are changed to adjust the backlash between the teeth of each gear. To be done.

FIG. 10 is a view showing a mounting portion of the sub base 48 to which the optical head drive mechanism 34 is mounted,
(A) is a plan view and (B) is a cross-sectional view. FIG. 10 (A)
As shown in (B), the sub-base 48 is provided with a mounting hole 80 for mounting the drive motor 37 and a mounting hole 82 for allowing the movable base 70 to move up and down. Positioning holes 84 and 8 for restricting the mounting position of the fixed base 68 are provided near the mounting holes 80 and 82.
5,86 are provided. In the vicinity of the mounting hole 82, screw holes 87, 88 for fixing the fixed base 68.
Is provided.

11A and 11B are views showing the structure of the fixed base 68. FIG. 11A is a plan view, FIG. 11B is a side view, and FIG. 11C is a front vertical sectional view taken along the line CC in FIG. is there. Figure 11
As shown in (A) to (C), the fixed base 68 is
It has a motor holding portion 68a for holding the drive motor 37, a space 68b, a shaft supporting portion 68c into which the end portion 38c of the lead screw 38b fits, and a shaft supporting portion 68d into which the end portion of the guide rail 36 fits. .

The fixed base 68 includes a sub base 4
Holes 68e and 68f corresponding to the eight screw holes 87 and 88 are provided. Further, on the lower surface of the fixed base 68, positioning bosses 68g to 68i that fit into the positioning holes 84, 85, 86 of the sub base 48 are projected.

A space 90 is formed between the screw holes 87 and 88 to accommodate the movable base 70 in a vertically movable manner.

12A and 12B are views showing the structure of the fixing plate 72. FIG. 12A is a plan view and FIG. 12B is a front view. Figure 1
2 (A) (B) as shown in FIG.
Is mounted and fixed on the upper surface of the fixed base 68. Therefore, the fixed plate 72 has holes 72a and 72b corresponding to the screw holes 87 and 88 of the sub base 48, and holes 72c and 72 to which the protrusions 70d and 70e of the movable base 70 fit.
d, a screw hole 72e into which the adjusting screw 60 is screwed, and rectangular holes 72f and 72g corresponding to the large diameter gear 56a of the reduction gear 56 and the driven gear 54 are provided.

13A and 13B are views showing the structure of the reduction gear 56, in which FIG. 13A is a horizontal cross-sectional view and FIG. 13B is a front view. As shown in FIGS. 13A and 13B, the reduction gear 56 is
A large-diameter gear 56a that meshes with the drive gear 52 and the driven gear 5
4 and a small-diameter gear 56b meshing with each other. Then, the reduction gear 56 has an axial hole 56c through which the shaft 62 is inserted and which penetrates in the axial direction.

14A and 14B are views showing the structure of the movable base 70. FIG. 14A is a plan view, FIG. 14B is a longitudinal sectional view taken along line BB in FIG. 14A, and FIG. 11 is a vertical cross-sectional view taken along the line C-C, and (D) is a vertical cross-sectional view taken along the line D-D in (A).
As shown in FIGS. 14A to 14D, the movable base 7
0 is the gear housing recess 70a, the pair of bearings 70b,
70c, protrusions 70d and 70e, and a gear storage recess 70
a bottom portion 7 having a hole 70f corresponding to the large diameter gear 56a
0g and arc-shaped relief portion 70 corresponding to the small diameter gear 56b
with h and. In addition, on the upper surfaces of the protrusions 70d and 70e,
Screw holes 70i and 70j into which screws 74 for fixing the movable plate 76 are screwed are provided. Further, the bearing portions 70b and 70c have a shaft hole 70 through which the shaft 62 is inserted.
k, 70m penetrates.

15A and 15B are views showing the structure of the leaf spring 78. FIG. 15A is a plan view, FIG. 15B is a side view, and FIG. 15C is a front view. As shown in FIGS. 15A to 15C, the leaf spring 78 has a contact surface 7 that contacts the lower surface of the movable plate 76.
8a and a through hole 78b penetrating the center of the contact surface 78a.
And inclined portions 78c and 78d that extend downward from both ends of the contact surface 78a.

The leaf spring 78 is inserted into the through hole 78b with the contact surface 78a contacting the lower surface of the movable plate 76 and the tips of the inclined portions 78c and 78d contacting the upper surface of the fixed plate 72. When the adjusting screw 60 is screwed into the screw hole 72e of the fixed plate 72, the distance between the fixed plate 72 and the movable plate 76 is reduced, and the adjustment is performed accordingly.

The leaf spring 78 is moved by the spring force according to the tightening amount (compression amount) of the adjusting screw 60.
Press upward.

16A and 16B are views showing the structure of the movable plate 76, FIG. 16A being a plan view and FIG. 16B being a side sectional view. As shown in FIGS. 16A and 16B, the movable plate 76
Has an oval outline and has insertion holes 76a and 76b through which a pair of screws 74 are inserted, and the adjusting screw 6.
An insertion hole 76c through which 0 is inserted is provided.

In the backlash adjusting unit 58 constructed as described above, as shown in FIGS. 7 and 8, the leaf spring is adjusted by adjusting the tightening position of the adjusting screw 60 screwed into the fixing plate 72. The compression amount of 78 changes, and the movable plate 76 fastened to the movable base 70 via the screw 74 moves up and down according to the compression amount of the leaf spring 78.

As a result, the reduction gear 56 includes the adjustment screw 6
It moves up and down with respect to the fixed base 68 while being supported by the movable base 70 according to the tightening position of 0. Therefore,
The reduction gear 56 moves up and down with respect to the drive gear 52 and the driven gear 54 by changing the height position of the movable base 70 according to the tightening position of the adjusting screw 60. At that time, in the reduction gear 56, the relative position of the drive gear 52 meshing with the large diameter gear 56a and the relative position of the driven gear 54 meshing with the small diameter gear 56b are changed to adjust the backlash between the teeth of each gear. To be done.

Next, a modified example of the backlash adjusting unit 58 will be described. 17A and 17B are diagrams showing a configuration of a modified example 1 of the backlash adjustment unit 58, where FIG. 17A is a plan view, FIG. 17B is a front view, and FIG. FIG. 17
As shown in (A) to (C), the backlash adjustment unit 100 of the modified example 1 includes a fixed unit 102 and a movable unit 104 movable with respect to the fixed unit 102.
It consists of and.

18A and 18B are views showing the structure of the fixing unit 102. FIG. 18A is a plan view, FIG. 18B is a front view, and FIG. 18C is a longitudinal sectional view. As shown in FIGS. 18A to 18C, the fixed unit 102 includes a fixed base 106 fixed to a chassis (not shown) and the like, and a bearing block 108 fixed to the upper surface of the fixed base 106. Bearing block 1
Fixing plate 110 fixed to the upper surface of 08, and the adjusting screw 1 screwed into the screw hole 110a of the fixing plate 110.
11 and a coil spring 112 assembled so as to be wound around the adjusting screw 111.

Further, the bearing block 108 has a drive gear (first gear) to which a rotational force from a drive motor (not shown) is input.
Bearing part 108a for bearing the shaft 114a of the gear 114 of FIG.
And a bearing portion 1 that supports a shaft 116a of a driven gear (second gear) 116 to which the rotational force from the drive gear 114 is transmitted.
08b and. In this modification, the drive gear 114
The driven gear 116 and the driven gear 116 are the same gear, and have the same pitch circle diameter and the same number of teeth.

Further, the bearing block 108 includes the bearing portion 1
The movable unit 104 is provided between the 08a and the bearing portion 108b.
And a space 108c into which is inserted.

19A and 19B are views showing the structure of the movable unit 104. FIG. 19A is a plan view, FIG. 19B is a front view, and FIG. 19C is a longitudinal sectional view. As shown in FIGS. 19A to 19C, the movable unit 104 includes a movable block 120 housed in the space 118 and a recess 1 of the movable block 120.
A reduction gear (3rd gear) rotatably supported in 21.
122 and a movable plate 124 fixed to the upper surface of the movable block 120.

A hole 124a through which the adjusting screw 111 is inserted is provided at an intermediate position of the movable plate 124.
The movable block 120 also includes a pair of bearings 120 a, 1 that support the end of a shaft 125 that penetrates the reduction gear 122.
It has 20b and the bottom part 120c which couple | bonds between a pair of bearing part 120a, 120b. In addition, the pair of bearings 120
Since the widths of a and 120b are smaller than the tip circle diameter of the reduction gear 122, the reduction gear 122 is supported so as to protrude to the left and right sides.

The reduction gear 122 has a pitch circle diameter larger than the distance between the drive gear 114 and the driven gear 116, and is formed so as to mesh with the drive gear 114 and the driven gear 116.

As shown in FIGS. 17A to 17C,
The movable block 120 is the space 108 of the bearing block 108.
When it is inserted into c, the reduction gear 122 is supported at an intermediate position between the drive gear 114 and the driven gear 116.
Therefore, with respect to the shaft 125 penetrating the reduction gear 122, the shaft 114 a of the drive gear 114 and the shaft 116 of the driven gear 116.
The shaft 114 is arranged in a position symmetrical with a.
a and 116a are supported at positions equiangular to the shaft 125.

In the backlash adjusting unit 100, when the adjusting screw 111 is tightened with the coil spring 112 interposed between the fixed plate 110 and the movable plate 124, the compression amount of the coil spring 112 is adjusted and the movable plate 124 moves up and down. .

As a result, the backlash adjusting unit 1
In 00, the height position of the reduction gear 122 supported by the movable unit 104 is adjusted, and the meshing position with respect to the drive gear 114 and the driven gear 116 is adjusted. As a result, the reduction gear 122 includes the drive gear 114 and the driven gear 1.
The relative position with respect to 16 changes, and the backlash between the teeth of each gear is adjusted.

FIG. 20 is a diagram showing the configuration of a second modification of the backlash adjusting unit 58, (A) being a plan view,
(B) is a front view and (C) is a side sectional view. Figure 20
As shown in (A) to (C), the backlash adjustment unit 130 of Modification 2 includes a fixed unit 132 and a movable unit 134 that is movable with respect to the fixed unit 132.
It consists of and. The movable unit 134 has substantially the same configuration as that of the movable unit 104, and a description thereof will be omitted. Further, in the fixed unit 132, the same parts as those of the fixed unit 102 are designated by the same reference numerals, and the description thereof will be omitted.

In the fixed unit 132, the drive gear 114
Has a smaller diameter than the driven gear 116. However, the drive gear 114 is supported such that the position of the shaft 114a is higher than the shaft 116a of the driven gear 116 by L.

Therefore, the shaft 1 passing through the reduction gear 122
25, the shaft 114a of the drive gear 114 and the driven gear 1
The sixteen shafts 116a are arranged symmetrically with each other, and the shafts 114a and 116a are supported at positions such as an angle α with respect to the shaft 125.

In the backlash adjusting unit 130, as in the case of the backlash adjusting unit 100, when the adjusting screw 111 is tightened with the coil spring 112 interposed between the fixed plate 110 and the movable plate 124, the coil spring 112 is compressed. The amount is adjusted and the movable plate 124 moves up and down.

As a result, the backlash adjusting unit 1
Also in 30, the height position of the reduction gear 122 supported by the movable unit 104 is adjusted to adjust the meshing position with the drive gear 114 and the driven gear 116. As a result, the reduction gear 122 includes the drive gear 114 and the driven gear 1.
The relative position with respect to 16 changes, and the backlash between the teeth of each gear is adjusted.

In the present embodiment, the drive mechanism 34 for driving the optical head 26 has been described as an example, but the present invention is not limited to this. Of course, it can be applied to a magnetic recording / reproducing device for recording / reproducing.

[0064]

As described above, according to the first aspect of the invention, the head having the drive unit for moving the head for reading the information on the recording medium and the transmission mechanism for transmitting the rotational drive force of the drive unit to the head. In the drive mechanism, the transmission mechanism includes a first gear to which the rotational drive force from the drive unit is input, a second gear to which the rotational drive force is transmitted via the first gear, and a first gear. Since a third gear is movably interposed between the second gear and the third gear, and an adjusting portion that adjusts a meshing position of the third gear with the first gear and the second gear is included, the third gear is provided. The backlash between the gears can be adjusted to an arbitrary gap by adjusting the mounting position of the gears. Therefore, the meshing position of the third gear with the first gear and the second gear can be adjusted relatively easily, and the backlash between the gears can be adjusted to a value as small as possible within the range where the load does not increase. Therefore, each gear can be adjusted in a short time so that it can rotate smoothly.

According to the second aspect of the invention, the adjusting portion includes a fixing portion that supports the first gear and the second gear,
Since the movable part is movably mounted on the fixed part and supports the third gear, and the adjustment screw for moving the relative position of the fixed part and the movable part to an arbitrary position is provided, the movable part is adjusted by the adjustment screw. By moving it, the meshing position of the third gear with the first gear and the second gear can be adjusted relatively easily, and the backlash between the gears can be adjusted to a value as small as possible without increasing the load. it can. Therefore, the backlash between the gears can be adjusted at the same time by turning one adjusting screw, and the labor of the adjusting work can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a disk device using a head drive mechanism according to the present invention.

FIG. 2 is a plan view of a disk device.

FIG. 3 is a plan view showing a state where the tray 20 is pulled out to a disc exchange position.

4 is an exploded perspective view showing an optical head 26 and an optical head cover 28. FIG.

FIG. 5 is a bottom view of the sub base 48 as seen from the lower surface side.

FIG. 6 is an enlarged horizontal cross-sectional view of an optical head drive mechanism 34.

FIG. 7 is a side vertical cross-sectional view showing a backlash adjustment unit 58 in an enlarged manner.

FIG. 8 is a front vertical cross-sectional view showing the meshing relationship of each gear.

9A and 9B are diagrams showing an arrangement of a drive gear 52 and a driven gear 54, FIG. 9A being a plan view and FIG. 9B being a transverse sectional view.

10A and 10B are views showing a mounting portion of a sub-base 48 to which the optical head drive mechanism 34 is mounted, where FIG. 10A is a plan view and FIG. 10B is a transverse sectional view.

FIG. 11 is a diagram showing a configuration of a fixed base 68,
(A) is a plan view, (B) is a side view, (C) is C in (A).
It is a front vertical cross-sectional view which follows the C line.

FIG. 12 is a diagram showing a configuration of a fixed plate 72,
(A) is a plan view and (B) is a front view.

FIG. 13 is a diagram showing a configuration of a reduction gear 56, (A)
Is a horizontal cross-sectional view and (B) is a front view.

FIG. 14 is a diagram showing a configuration of a movable base 70,
(A) is a plan view, (B) is a vertical sectional view taken along line BB in (A), (C) is a vertical sectional view taken along line CC in (A),
(D) is a vertical cross-sectional view taken along line D-D in (A).

15A and 15B are views showing a configuration of a leaf spring 78, FIG. 15A is a plan view, FIG. 15B is a side view, and FIG. 15C is a front view.

16 is a diagram showing a configuration of a movable plate 76, FIG.
(A) is a plan view and (B) is a side sectional view.

17A and 17B are views showing a configuration of a modified example 1 of the backlash adjustment unit 58, where FIG. 17A is a plan view, FIG. 17B is a front view, and FIG.

FIG. 18 is a diagram showing a configuration of a fixed unit 102,
(A) is a plan view, (B) is a front view, and (C) is a longitudinal sectional view.

FIG. 19 is a diagram showing a configuration of a movable unit 104,
(A) is a plan view, (B) is a front view, and (C) is a longitudinal sectional view.

20A and 20B are views showing a configuration of a modified example 2 of the backlash adjustment unit 58, FIG. 20A is a plan view, FIG. 20B is a front view, and FIG.

[Explanation of symbols]

11 Disk device 16 Lower cover 18 turntable 20 trays 22 discs 26 Optical head 27 Objective lens 28 Optical head cover 30 front bezel 40, 42 guide rails 34 Optical head drive mechanism 35, 36 guide shaft 37 Drive motor 38 Transmission mechanism 38a gear mechanism 38b lead screw 46 Optical head unit 48 sub-base 52 drive gear 54 Driven gear 56 reduction gear 56a large diameter gear 56b small diameter gear 58,100,130 Backlash adjustment unit 60 adjustment screw 68 fixed base 70 Movable base 72 Fixed plate 76 Movable plate 78 leaf spring 102,132 Fixed unit 104,134 Mobile unit 106 fixed base 108 Bearing block 110 fixed plate 111 Adjustment screw 112 coil spring 114 drive gear 116 Driven gear 120 movable blocks 122 reduction gear 124 Movable plate

Claims (2)

[Claims] 1. A head drive mechanism having a drive unit for moving a head for reading information on a recording medium, and a transmission mechanism for transmitting a rotational drive force of the drive unit to the head, wherein the transmission mechanism is the drive unit. Between the first gear to which the rotational driving force from the first gear is input, the second gear to which the rotational driving force is transmitted via the first gear, and the first gear and the second gear A movably intervening third gear, and an adjusting portion for adjusting the meshing position of the third gear with the first gear and the second gear. Drive mechanism. 2. The adjusting portion includes a fixed portion that supports the first gear and the second gear, a movable portion that is movably mounted on the fixed portion and that supports the third gear, The head driving mechanism according to claim 1, further comprising: an adjusting screw that moves a relative position between the fixed portion and the movable portion to an arbitrary position.