JPS6129465A - Pick-up driving mechanism of optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To perform an information position control with high precision by engaging a gear in the final stage of a gear row of driving system with a rack fixed to a fixed stand of a feeding table fixed with a pickup. CONSTITUTION:A pick up 2 is fixed to a feed table 3, a helical rack 16 is fixed to a fixed stand of the pick-up feed table 3 with plural screws 17, to which a gear 18 on the final stage of a driven system gear row is engaged. In this way, a helical gear is used for the final gear 18, and it becomes great in meshing rate by using it in combination with the helical rack 16, so that power may be smoothly transmitted. In this invention, the gear with backlash prevention mechanism is set on the gear row to be used for the driven system from a driven motor to the pick-up feed table. Therefore, no play is produced in the driven system so that the information position control with high precision is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a pickup drive mechanism for an optical information recording/reproducing device.

Prior Art In a conventional CD (compact desk) player,
Access speed is not required as it is often used for playback only or for general users to simply listen to music.

Therefore, since it is sufficient to read the ζ tracks one by one and send them to a predetermined position, it is sufficient to send them slowly without using an encoder or the like in the access system.

However, since recent optical desks are used as external storage devices for computers, the diameter of the disks is large, and they are required to have fast access speeds and high positional accuracy.
A linear motor such as a CM (voice coil motor) is used, which has the problem of making the device large and expensive.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a drive mechanism for an optical pickup for storing information that is small in size, low in cost, has a high access speed, and has high accuracy.

Summary of the Invention By using a brushless DC motor as the drive motor and a backlash-free gear train in the power transmission system, a drive mechanism for an optical pickup that is simple, compact, and highly accurate in detecting information position is obtained. Especially,
A pickup fixed to a feed table that moves along a guide shaft and a rack fixed to a fixed base of the pickup feed table are engaged with the final stage gear of the drive system gear train, and the final stage gear In this invention, a pickup drive mechanism for an optical information recording/reproducing device without backlash is obtained by using a two-piece rack having a helical gear and a helical bulk or backlash prevention mechanism.

Example Hereinafter, the present invention will be explained in more detail with reference to Examples.

FIG. 1 is a plan view of an embodiment of the present invention, and FIG. 2 is a sectional view showing its gear train.

1 is a well-known type of pickup having a lens 2 for reading optical information, and is fixed to a feed table 3 with three screws, and the feed table 3 has two guide shafts 4 and 6.
It is designed to move along the

The feed table 3 is fitted to the guide shaft 4 by a sliding bearing made of oilless metal, etc., and the feed table 3 is fitted to the guide shaft 6 by a substantially U-shaped guide 111! (not shown) so that the feed table and the pickup can move smoothly with respect to the guide shafts 4 and 6 by preventing vertical play. .

7 is a drive motor, 8 is a gear directly connected to the motor shaft, and is engaged with intermediate gears 9 and 10. The intermediate gear 10 is rotatably attached to the gear 9 and has a backlash prevention/prevention mechanism which will be described later.

The pinion 12, which is made integral with the gear 9, drives a gear 13, 14 which is coaxial with the last gear 18 of the gear train. These gears 13 and 14 also have a backlash prevention mechanism which will be described later.

FIG. 3 shows an embodiment of the backlash prevention mechanism of the gears 9, 10, 13, and 1.4 described above, in which the gear 14 is rotatable relative to the gear 13. Engagement holes 14G and 130 are provided for the engagement claws 101 and 102 of the coil spring 11, and the two gears 1
3.14 are connected by a coil spring 11, overlapped and prevented from being pulled out with an E ring 15, thereby forming a mating gear.

Therefore, when engaged with the gear 12, by displacing the gear 14 to the gear 13 by an appropriate amount (for example, a rotation angle corresponding to 1 to 2 teeth) against the elasticity of the coil spring 11, and engaging the gear 14, This constitutes a backlash prevention mechanism.

This also applies to the gears 9 and 10, so a description thereof will be omitted.

Reference numeral 1B is a helical bulkhead fixed to the feed table 3 with a plurality of screws 17, and is engaged with the final gear 18.

The final gear 18 is a helical gear, and when used in combination with the helical gear 16, it has a high engagement ratio, smooth power transmission, and is also effective as a backlash prevention mechanism.

FIG. 4 shows another embodiment of the backlash prevention mechanism, in which a spur gear 18' is used as the final stage gear, and a rack 19, 20 of two spur gears is used on the feed table side. The racks 19 and 20 are attached to the feed table 3 with a plurality of screws 17', and the rack 19 is provided with horizontally elongated through-holes 21 and 22 in the longitudinal direction.
0, and a longitudinal sliding force is applied by a spring 23.

Therefore, when the gear 18' and the rack 19.20 are engaged, by shifting the rack 19 with respect to the rack 20 by an appropriate number of teeth, the teeth of the gear 18' are engaged on both sides by the teeth of the rack 19.20. The backlash prevention mechanism is configured by being elastically sandwiched between the two.

The pickup drive mechanism of the present invention having the above configuration is as follows:
The amount of movement of the pickup 1 is controlled by attaching an encoder disk 21 to a part of the final stage gear of the gear train of the drive system. That is, the driving force of the motor 7 is transferred to the gear train 8.
Since the encoder desk 21 is rotated through steps 14 to 14,
The feed table 3 is moved by the rack that engages with the final gear, and the ζ pickup 1 can be moved along the guide axis to access a predetermined position on the optical desk.

Effects of the Invention According to the present invention, the gear train used in the drive system from the drive motor to the feed table of the pickup is provided with a gear with a backlash prevention mechanism. There is no mechanical play in the drive system along the way. In addition, since the encoder is installed at the final stage of the drive system, the encoder can control the pickup position without being affected by the rigidity of the transmission mechanism, improving feed accuracy and ensuring reproducibility. This makes it possible to obtain an inexpensive pickup drive mechanism.

In particular, in the present invention, in addition to the backlash prevention mechanism using mating gears, a Hespa gear is used, so an even more effective backlash prevention mechanism can be obtained, and as a result, highly accurate pickup position control can be achieved. Therefore, a possible drive mechanism can be obtained.

In addition, in the embodiment of the present invention, the encoder is provided on the final stage gear, but as mentioned above, the drive system of the present invention is provided with a backlash prevention mechanism, so the encoder cannot be driven. The information position of the pickup and the position detected by the encoder will not deviate from each other no matter where in the system it is installed, and highly accurate information position control can be performed.

Furthermore, by using a DC brushless motor as the drive motor 7, a servo sliding circuit with a long life and simple circuit design without noise or cogging (torque unevenness) can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment of the present invention, and FIG. 2 is an I
! It is a sectional view showing the fl east row. FIG. 3 shows one embodiment of the backlash prevention mechanism, and the fourth
The figure is a perspective view showing another embodiment of the backlash prevention mechanism. 1...Pickup 2...Reading lens 3...Feed table 4.5...Guide shaft 7...Motor 8-14 ... Gear train 11 ... ... Coil spring 16 ... Lotus barracks 18.18' ... Final stage gear 19.20 ... Spur gear rack 21 ...・・・・・・Enfunder Desk Figure 1 Figure 2 Figure 3 Figure 4 Procedural Amendment (Spontaneous) December 11, 1980 1. Indication of Case 1989 Patent Application No. 124803 2. Invention Name of Pickup Drive Mechanism 3 of Optical Information Recording and Reproducing Device, Relationship with the Case of the Person Making the Amendment Patent Application Person Address: 2-43-2-4, Hatagaya, Shibuya-ku, Tokyo
[Claims] column of the description] (1) Amend the claims as shown in the attached sheet. 7. List of attached documents (1) Attachment 1 attachment Attachment 2. Claims (1) A pickup fixed to a feeding table that moves along a guide shaft, and a pickup fixed to a fixed base of the pickup feeding table A pickup drive mechanism for an optical information recording/reproducing device, characterized in that a final stage gear of a drive system gear train is engaged with a rack in which a drive gear is provided. (3) The pickup drive mechanism according to claim 1, wherein the final stage gear is engaged with a pair of racks, one of which is provided with a sliding force in the longitudinal direction by a spring.

Claims (3)

[Claims] (1) A pickup fixed to a feed table that moves along a guide shaft and a rack fixed to a fixed base of the pickup feed table are engaged with the final stage gear of the drive system gear train. A pickup drive mechanism for an optical information recording/reproducing device. (2) A helical gear is used for the final stage gear, and a gear with a backlash prevention mechanism is integrally provided, which is a mating gear that connects both gears with a coil spring installed between the two gears. Claim 1 characterized by
Pickup drive mechanism described in section. (3) The final stage gear is connected to a rack with a backlash prevention mechanism, which is made up of two racks, one of which is given a sliding force in the longitudinal direction by a spring. Pickup drive mechanism as described in section.