JPH11185408A - Pickup feed device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep a load exerted on a screw shaft always constant irrespective of the direction of rotation of the screw shaft used to give a feed force to a pickup in a pickup feed device used for a disk player or the like. SOLUTION: A support 2 is attached to a base 1 which is provided with a pickup P. A nut body 3 which is composed of a half nut is attached to an arm part 23 at the support 2. Arc-shaped feed teeth 31 on the nut body 3 are engaged with a screw groove 41 on a screw shaft 4. A pair of sliding bodies 6, 6 which come into sliding contact with the outer circumferential face of the screw shaft 4 on both sides of the central line C in a place in which the screw groove 41 is engaged with the feed teeth 31 are installed additionally in the nut body 3. Tips of the sliding bodies 6, 6 are spherical.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pickup feeder, and more particularly, to a nut shaft which is engaged with a screw shaft which rotates forward and backward, and a base provided with a pickup is connected to the nut unit via a support. The present invention relates to a pickup feeding device.

[0002]

2. Description of the Related Art A pickup feeder of this type employed in a disc player or the like has a support attached to a base provided with a pickup (optical pickup).
The feed dog of the nut body attached to this support is meshed with the screw groove of the screw shaft, and the base is
The movement is guided by a guide shaft parallel to the screw shaft.

In such a pickup feeder, if a half nut is used for the nut body 3, for example, when the screw shaft rotates in the forward direction, the nut body is moved in the direction in which the feed dog bites into the screw groove. On the other hand, when a force is applied, when the screw shaft rotates in the opposite direction, a force is applied to the nut body in a direction for lifting the feed dog from the screw groove. Therefore, when the screw shaft rotates in the forward direction and when the screw shaft rotates in the reverse direction, the magnitude of the load such as the starting load and the feed load applied to the screw shaft is different, which is not preferable.

Therefore, for example, Japanese Patent Application Laid-Open Nos. Hei 5-89612, Hei 5-81681, Hei 4-609
No. 70, etc., have proposed a countermeasure for canceling the difference in the magnitude of the load such as the starting load and the feed load due to the difference in the rotation direction of the screw shaft by using the elasticity of a leaf spring or rubber. ing.

[0005]

However, the pickup feeder described in each of the above publications has a problem that the structure thereof is complicated and it is difficult to reduce the manufacturing cost of the pickup feeder.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a simple structure, and can reliably cancel the difference in the starting load and the feed load due to the difference in the rotation direction of the screw shaft. It is another object of the present invention to provide a pickup feeder in which a load applied to a screw shaft is kept constant regardless of the rotation direction of the screw shaft.

[0007]

According to the present invention, there is provided a pickup feeder comprising: a screw shaft having a screw groove; a screw shaft which is movable along the screw shaft and which writes information on a disk or writes information recorded on the disk. A support having a base for reading, a mounting portion attached to the base and an arm extending from the mounting portion, and a screw attached to the arm of the support and A pickup body comprising a nut body having a feed dog meshing with a shaft, wherein the nut body is formed by a half nut having an arcuate feed dog meshing with a screw groove of the screw shaft; A pair of sliding members that are in sliding contact with the outer peripheral surface of the screw shaft on both sides of the center line of the meshing point between the screw groove and the feed dog. Are attached, is that.

When the pickup feeder is configured as described above, the force to be applied to the nut body when the screw shaft rotates is received by the pair of sliding members slidingly contacting the outer peripheral surface of the screw shaft. So, in the nut body,
The force in the direction in which the feed dog bites into the screw groove of the screw shaft and the force in the direction in which the feed dog rises from the screw groove are not applied. Therefore, the relative positional relationship between the screw groove of the screw shaft and the feed dog of the nut body meshing with the screw shaft is kept constant irrespective of the rotation direction of the screw shaft, which means that the load applied to the screw shaft, that is, This helps to keep the starting load and feed load constant.

In such a pickup feeder, the contact surfaces of the pair of sliding members with the outer peripheral surface of the screw shaft are desirably formed as spherical surfaces. The contact resistance with the outer peripheral surface of the screw shaft is suppressed to the minimum limit, and it becomes difficult to increase the load applied to the screw shaft. Further, it is desirable that the support is made of a leaf spring, and by adopting this configuration, the feeding action of the nut body by the screw shaft is stabilized.

[0010]

FIG. 1 is an explanatory view schematically showing an embodiment of a pickup feeder according to the present invention, and FIG.
FIG. 2 is a schematic cross-sectional view of a portion along line II-II of FIG.

In FIG. 1, reference numeral 1 denotes a base, which is provided with a pickup (for example, an optical pickup) P facing a disk (for example, optical disk) D indicated by a virtual line. The mounting portion 21 of the support 2 made of a band-shaped leaf spring manufactured by performing bending or the like is provided on the base 1.
2 is fixed. The support 2 has an arm portion 23 extending from the mounting portion 21.
The nut body 3 is fixed to the bent portion 24 at the end of the nut 3.
The screw shaft 4 has a screw groove 41, and the feed dog 31 of the nut body 3 is engaged with the screw groove 41. The movement of the base 1 is guided by a guide shaft 5 parallel to the screw shaft 4.

The arm 23 of the support 2 made of a leaf spring
Can be elastically bent and deformed in the direction near and far from the screw shaft 4 around the boundary with the mounting portion 21, that is, with the base of the arm 23 as a fulcrum 25. Further, a half nut whose feed dog 31 has a substantially semicircular arc shape is used as the nut body 3, and the feed dog 3 of the nut body 3 is used.
The center of one arc is located on the axis 42 of the screw shaft 4.

Next, the nut body 3 has an outer peripheral surface 42 of the screw shaft 4 on both sides of a center line C of a location where the screw groove 41 of the screw shaft 4 meshes with the feed dog 31 of the nut body 3. A pair of sliding members 6 and 6 that are in sliding contact are provided. Contact surfaces 6 of these sliding members 6 and 6 with the outer peripheral surface 42 of the screw shaft 4
Reference numerals 1 and 61 are formed as spherical surfaces. Therefore, the contact surfaces 61, 61 of these sliding bodies 6, 6 are theoretically
Is in point contact with the outer peripheral surface 41. Further, the distance from the center line C to the contact point between the contact surfaces 61, 61 of the pair of sliding bodies 6, 6 and the outer peripheral surface 41 of the screw shaft 4 is the same.

In this embodiment, as shown in FIG. 2, the two nut bodies 3 are fixed to the bent portion 24 of the arm portion 23 at intervals of one pitch of the screw groove 41 of the screw shaft 4. The feed teeth 31, 31 of the respective nut bodies 3, 3 are engaged with the screw grooves 41. Then, the pair of sliding bodies 6, 6 are located at the intermediate positions of these nut bodies 3, 3 at the bent portions 2 of the support 2.
4.

In the pick-up feeder thus configured, when the screw shaft 4 is driven to rotate in the forward direction a or the reverse direction b by a pulse motor (not shown) as a drive source, the screw shaft 4 meshes with the screw shaft 4. The nut body 3 is moved forward or backward, and the base 1 is moved forward or backward following the forward movement or backward movement of the nut body 3. Then, the pickup P performs writing of information on the disk D and reading of information recorded on the disk D.

Here, when the screw shaft 4 rotates in the forward direction as indicated by the arrow a in FIGS. 1 and 2 or when the screw shaft 4 rotates in the reverse direction as indicated by the arrow b, the screw shaft 4 is rotated. Although a force in a direction corresponding to the rotation direction of the screw shaft 4 is to be applied to the nut body 3 engaged with the screw groove 41 of the screw shaft 4, such a force is applied to a pair of the sliding surfaces of the outer peripheral surface 42 of the screw shaft 4. Since it is received by the sliding bodies 6, 6,
No force is applied to the nut body 3 in a direction that causes the feed dog 31 to bite into the screw groove 41 of the screw shaft 4 or a force that causes the feed dog 31 to float up from the screw groove 41. Therefore, the relative positional relationship between the screw groove 41 of the screw shaft 4 and the feed dog 31 of the nut body 3 meshing with the screw groove 41 is kept constant regardless of the rotation direction of the screw shaft 1.
The load applied to the screw shaft 4, that is, the magnitude of the starting load and the feed load is also kept constant.

Further, in this embodiment, since the contact surfaces 61, 61 of the pair of sliding members 6, 6 with the outer peripheral surface 41 of the screw shaft 4 are formed as spherical surfaces, the sliding members 6, 6 and the screw shaft 4 are formed. The contact resistance with the outer peripheral surface 41 of the screw shaft 4 is minimized, and the load applied to the screw shaft 4 hardly increases. Furthermore, since the support 2 is formed of a leaf spring, even if vibration occurs in the nut body 3 sent by the screw shaft 4, the vibration is absorbed by the support 2 and the nut body 3 is fed by the screw shaft 4. The action becomes stable.

[0018]

According to the present invention, in a pickup feeder used in a disk player or the like, the load applied to the screw shaft is kept constant regardless of whether the screw shaft rotates in the forward direction or the reverse direction. Therefore, there is an effect that the followability of the base including the pickup is improved with respect to the rotation of the screw shaft.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing an embodiment of a pickup feeding device according to the present invention.

FIG. 2 is a schematic cross-sectional view of a portion along the line II-II in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Support body 3 Nut body 4 Screw shaft 6 Sliding body 21 Attachment part 23 Arm part 31 Feed dog 41 Screw groove 42 Outer peripheral surface of screw shaft 61 Contact surface C Centerline of the meshing point between screw groove and feed dog D Disc P pickup

Claims (3)

[Claims] A base provided with a screw shaft having a screw groove, a pickup movable along the screw shaft, and for writing information to a disk or reading information recorded on the disk; A support having a mounting portion mounted on the base and an arm extending from the mounting portion, and a nut body having a feed dog mounted on the arm of the support and meshing with the screw shaft. In the pickup feeding device, the nut body is formed by a half nut having an arcuate feed dog meshing with the screw groove of the screw shaft, and the nut body meshes with the screw groove and the feed dog. A pair of sliding members, which are in sliding contact with the outer peripheral surface of the screw shaft on both sides of the center line of the portion, are provided. . 2. The pickup feed device according to claim 1, wherein a contact surface of the pair of sliding bodies with an outer peripheral surface of the screw shaft is formed as a spherical surface. 3. The pickup feeding device according to claim 1, wherein the support is a leaf spring.