JPS6129464A - Pickup drive mechanism of optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To improve the feeding accuracy by providing a pickup fixed to a feeding table and an alpha belt fixed to a fixed stand of a pickup feeding table and fixing integrally the alpha belt to a part of a final stage gear. CONSTITUTION:The pickup drive mechanism has the pickup 1 fixed to the feeding table 3 and the alpha belt 16 fixed to a fixed stand of a pickup feeding table 3. Then the alpha belt 16 is fitted to a pulley 133 integrally with the final stage gear 13 of a gear train provided with a backlash preventing mechanism by means of a screw. Since the gear with the backlash preventing mechanism is provided to the gear trains used from the drive motor to the feeding table of the pickup in this way, mechanical play is caused, and the feeding accuracy is improved and reproducibility are ensured.

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 Conventional CD (compact disc) players are often used only for playback or used simply by general users to listen to music, and therefore access speed is not so demanding.

Therefore, since it was sufficient to read each track one by one and send it to a predetermined position, it was better to send it 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.

Purpose of the Invention The present invention is small, low-cost, has fast access speed,
The object of the present invention is to provide a drive mechanism for an optical pickup for storing information with high accuracy.

Summary of the invention A high-speed optical pickup drive mechanism is obtained.
In particular, it has a pickup fixed to a feed table that moves along a guide shaft, and an α belt fixed to a fixed base of the pickup feed table, and the α belt is connected to the final stage gear of the gear train of the drive system. This is a pickup drive mechanism of an optical information recording/reproducing device that is integrally fixed to the drive system.The last gear of the drive system is equipped with an α belt, and the gear train of the drive system is equipped with a backlash prevention mechanism, and the information between the encoder desk and the pickup is This eliminates positional deviations, provides fast access speed, and provides a highly accurate pickup drive mechanism.

Example Hereinafter, the present invention will be specifically explained with reference to Examples.

FIG. 1 is a plan view of an embodiment of the present invention, and FIG. 2 is a partially enlarged perspective view thereof.

FIG. 3 is a sectional view showing the 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 5.
It is designed to move along the

The feed table 3 is fitted to the guide shaft 4 by a sliding bearing made of oil-less metal, etc., and the feed table 3 is fitted to the guide shaft 5 by an arm 6 having a substantially U-shaped guide groove (not shown). The feed table and the pickup are designed to slide together, and the feed table and the pickup are prevented from rattling up and down with respect to the guide shafts 4 and 5, so that they can move smoothly.

7 is a drive motor, 8 is a gear directly connected to the motor shaft, and is engaged with an intermediate gear 9.10. The intermediate gear 10 is rotatably attached to the gear 9 and has a backlash prevention mechanism described later.

The pinion 12, which is made integral with the gear 9, drives the final gear 13, 14 of the gear train. This final stage tooth 111
3 and 14 also have a backlash prevention mechanism which will be described later.

Figure 4 is the aforementioned tooth! 9, 10, and 13. In one row showing the backlash prevention mechanism of 14, gear 14 is the same as gear 1.
It is rotatable relative to 3. Gears 13 and 14 have
Engagement holes 140 and 130 are provided for the engagement claws 101 and 102 of the coil spring 11, respectively, and the two gears 13
．． 14 are connected by a coil spring 11, overlapped and prevented from being pulled out by an E ring 15, thereby forming a mating gear. Therefore, when engaged with the gear 12, by displacing the gear 14 by an appropriate amount (for example, a rotation angle corresponding to 1 to 2 teeth) with respect to the coil spring 13 against the elastic force of the coil spring 110, and engaging the gear 14, backlash can be prevented. This constitutes a prevention mechanism. This also applies to gears 9 and 10, so a description thereof will be omitted.

What is shown in FIG. 6 is another example of a gear backlash prevention mechanism.

Two engagement pins 131 are provided protruding near the outer periphery of the gear 13' that transmits the driving force. The number of engagement pins can be set as required depending on the magnitude of the transmitted torque.

Further, the tip end 132 of the shaft of the gear 13' has a slightly larger diameter than the inner diameter 141 of the gear 14', and is provided with a plurality of grooves.

An elastic tongue piece 141 is protruded from the gear 14' at a position corresponding to the engagement pin 131 of the gear 13'.

Then, by overlapping the gear 13' and the gear 14' with the engagement pin 131 located on one side of the tongue piece 141, the tip 132 of the gear 13' is displaced by the kerf, and the gear 14' is After passing through the inner diameter 141, it returns again due to its elastic force to form a pull-out stop, and the gears 13' and 14' constitute a mating gear.

Therefore, when engaging with another gear, the backlash prevention mechanism is achieved by displacing the gear 14' by an appropriate amount (for example, a rotation angle corresponding to 1 to 2 teeth) and engaging the gear 13'. It is composed.

An α belt 16 is attached to the final stage tooth 13 of the gear train provided with such a backlash prevention mechanism to a pulley portion 133 that is integrated therewith with screws or the like. Both ends of this α-belt 1B are fixed to α-belt fixing bases 17 and 18 fixed to the feed table 3, respectively, and the α-belt fixing base has a step 170 inward to ensure tension of the α-belt. , 180 are formed. In other words, the α belt 16 wound around the pulley portion 133 can move the table 3 with constant tension without contacting the fixed table due to the relief portion created by the step.

In addition, in order to constantly apply tension to the α belt and to provide appropriate tension during assembly work to facilitate assembly, the belt fixing base 17.18 has horizontally long through-mounting holes 173, 183. is provided, and two belt fixing stands 1″7
, 18, and by press-fitting a coil spring 19 between the fixing bases 17 and 18, it is possible to always apply tension to the α belt 16.

To attach the α belt to the pulley portion 133 of the gear 13,
First, the α' belt 16 is wound around the pulley portion 133 and fixed with small screws as shown in FIG. 4, and then both ends of the α belt are secured to the fixing bases 17 and 18.

The fixed base 17.18 also has a guide wall 171 for the α belt.
, 172 and 181, 182 are provided, and when the α belt is installed on the fixed base, both are installed completely parallel without tilting, and the α belt is devised to prevent the tension applied to the α belt from shifting. be.

FIG. 5 is an explanatory diagram of the shape of the α belt, where FIG. 5(A) shows the conventional α belt, and FIGS. 5(B) and 5(C) show the α belt used in the present invention.

As shown in FIG. 5(A), the conventional α belt has a wide part 160 on one side, and a long hole space 162 is formed therein, and the width of the long hole space is the opposite side of the α belt. It is slightly wider than the narrow belt portion 161 on the side, so that the two can cross each other.

However, when considering the material required to manufacture the α belt, as shown in the figure, a fairly long piece must be punched out, and the material in the long hole space 162 must be wasted, which increases the material cost. It has the disadvantage of being relatively expensive.

Therefore, the α belt used in the present invention has one metal belt with one hollow slit, as shown in FIG. 5(b).
63 is punched out, and the remaining metal portion is folded back as shown in FIG. 5(c) to form a narrow belt portion 161.

That is, by punching out a single metal belt, a narrow belt portion is punched out from a wide belt and folded back to form a single narrow belt portion. Therefore,
The α-belt used in the present invention can be manufactured from a material with half the length compared to conventional ones, and the folded part is overlapped and screwed to the pulley of the gear, so there is a problem with strength. does not occur at all.

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 2o to a part of the final stage gear of the gear train of the drive system.

That is, since the driving force of the motor 7 rotates the encoder desk 2o via the gear train 8 to 14, the feed table 3 is moved by the α belt fixed to the pulley of the final stage gear, and the pickup 1 is moved to the guide shaft. move along
This allows access to a predetermined location 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, so that the final stage gear from the motor to the encoder attached There is no mechanical play in the drive system along the way, and 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. Therefore, it is possible to improve the feeding accuracy and ensure its reproducibility, and also to obtain a compact and inexpensive pickup drive mechanism.

In the embodiments 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 is installed in the drive system. No matter where the pickup is installed, the information position of the pickup and the position detected by the encoder will not deviate, and highly accurate information position control can be performed.

Furthermore, by using a DC brushless motor as the drive motor 7, a servo drive 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, FIG. 2 is a partially enlarged perspective view thereof, and FIG. 3 is a sectional view showing a gear train. Figure 4 is an explanatory perspective view of the backlash prevention mechanism, $5
The figure is an explanatory diagram of the shape of the α belt, and Figure 5 (a) is the conventional α belt.
Belt, Fig. 5 (Roll 9 shows the Rel α belt used in the present invention. Fig. 6 is a perspective view showing another example of the gear backlash prevention mechanism. 1. ...Pickup 2...Reading lens 3...Feeding table 4.5...Guide shaft 7... ...Motor 8-14...Gear train 11...Coil spring 13,14...Final stage gear 16 of gear train...α belt 20... ...?...Encoder desk 131...
...Engagement pin 141...Tang piece 160...Wide part 161...Narrow width belt part 162...
...Elongated hole space 163...Slit Fig. 1 Fig. 3 '10 Fig. 4 Fig. 5 (a)] (Han Fig. 6 procedural amendment (voluntary) Commissioner of the Patent Office Manabu Shiga Name of the case Patent Application No. 124802 filed in 1982 2 Name of the invention Pick-up drive mechanism for optical information recording and reproducing device 3 Person making the amendment Relationship in the case Patent applicant Address 2-43 Hatagaya, Shibuya-ku, Tokyo No. 2 No. 4, Agent 6, Subject of amendment 7, Contents of amendment (1) The scope of claims is corrected as shown in the attached sheet. (2) From line 13 to line 14 of page 6 of the specification This is corrected as an example of a well-known backlash prevention mechanism in which 1 is applied to r13 and r14 in one column showing the backlash prevention mechanism of '13.14. (3) Specification, page 7, item 7 (4) Correct "Other Examples" written in page 7, line 8 of the specification to "l Example". ( 5) "Figure 4 shows backlash," written on page 13, line 6 of the specification, is corrected to "Figure 4 shows the well-known backlash." (6) "Figure 4 shows backlash," written on page 13, line 6 of the specification. ``In Figure 6, the other 1 of the gear backlash prevention mechanism is corrected to ``Figure 6 is 1 implementation of the backlash prevention mechanism of the present invention.'' Attachment 2, Claims (1) Guide shaft It has a pickup fixed to a feed table that moves along A pickup drive mechanism of an optical information recording and reproducing device, characterized in that the pickup drive mechanism is fixed to the optical information recording/reproducing device. (2) The feeding table extension belt fixing base is formed with a recessed relief by a step to ensure the tension of the α heald. The pickup drive mechanism according to claim 1, characterized in that: (3) The α belt is formed by punching out a narrow heald part from a wide heddle by hollowing out a single metal belt and folding it back. , a pickup drive mechanism according to claim 2, characterized in that it is formed by a single narrow heald portion. (4) A final gear shaft of the drive system is provided with a mechanism for controlling the position of the pickup. The pickup drive mechanism according to claim 1, characterized in that an encoder desk is provided for the pickup drive mechanism. (5) A gear train that can be used in the drive system is provided with a gear with a backlash prevention mechanism. The pickup drive mechanism according to claim 1, characterized in that the backlash prevention mechanism is connected by an elastic tongue protruding from one gear and an engagement pin protruding from the other gear. 6. The pickup drive mechanism according to claim 5, wherein the pickup drive mechanism is a matching gear. m. The backlash prevention mechanism is a mating gear connected by a tongue protruding from one gear and an elastic engagement pin protruding from the other gear. pickup drive mechanism. Procedural amendment (voluntary) Manabu Shiga, Commissioner of the Japan Patent Office1, Indication of the case, Patent Application No. 124802 of 1982, Name of the invention Pickup drive mechanism for optical information recording and reproducing device3, Person making the amendment Relationship to the case Patent Applicant Address: 2-43-2-4, Hatagaya, Shibuya-ku, Tokyo, Agent 5, Jie 66 (I) Page 11 of the specification, between lines 17 and 18 Insert the following description: "Fig. 7 is a schematic plan view of a pickup drive mechanism showing another embodiment of the present invention, and Fig. 8 is a sectional view of the main parts thereof. 1 is an optical information reading device. It is a well-known type of pick-up with a lens 2 for use, and is fixed to a feed table 3 with three screws 4, and two table support arms 301 and one support arm 303 support two guides. axis 6,
7. Slide bearings 5 made of oil-less metal or the like are press-fitted into the two support arms 301, and the support arms 303 sandwich the guide shaft 7 between two bearing plates 313 and 323, as shown in FIG. There is. Reference numeral 302 denotes a table drive arm provided on a part of the feed table 3 of the pickup 1, and an elastic pin 19 shown in FIG. 8 is attached to the tip of the arm by a known fixing means such as a screw. This elastic pin 1
9 is elastically pressed against the feed screw 10. To elastically press the elastic pin 19 and the feed screw 10,
The pin 19 may be tilted in advance with respect to the direction of the feed screw, or the axis of the feed screw 10 may be adjusted in position relative to the pin 19, so that the feed screw itself can be moved closer to or further away from the pin 19. You can do it like this. 8 is a drive motor, 9 is a spur gear fixed to the motor shaft, and two spur gears 11°1 are fixed to the feed screw 10.
2 at the same time. Reference numeral 15 denotes a bearing case containing a radial bearing 14, which rotatably supports the feed screw lO together with the e-bot bearing 18, and between it and the thrust bearing 17 provided on one side of the feed screw 10. Thrust wing 1
6 is interposed, thereby pressing the feed dog 10 against the pivot bearing to prevent play in the axial direction. The pivot bearing 18 receives the axial force from the thrust spring 16 as described above, and also controls the axial position of the feed dog.
This is ensured by its self-aligning mechanism. ’20 is an Encoradial desk with 10 spur gears and 11.1 spur gears.
The encoder detection circuit 21 detects the code on the desk and controls the position of the pickup 1.
It controls the FIG. 9 and FIG. 1θ show the above embodiments (FIGS. 7 and 8).
FIG. 3 is a perspective view and a cross-sectional view of the main parts of a mechanism for preventing vertical play of the pickup in the table support arm 30.
This corresponds to the detailed part of 3. The table support arm 303 forms a substantially U-shaped wedge portion formed by an upper bearing plate 313 and a lower bearing plate 323, and the upper and lower bearing plates each have surfaces 305 and 306 that are inclined with respect to the moving direction of the shaft. is formed to reduce friction between the edges and the shaft. 305 is a hole for the screw 23 provided in the upper bearing plate, and the lower bearing plate 306 has a hole for the screw 23.
A female screw hole 304 for No. 3 is provided. 22 is a spring for elasticity adjustment, and as shown in FIG. 8, the upper bearing plate 313 and lower bearing plate 323 of the table support arm 303
Since the guide shaft 7 is press-fitted between the table support arm 301 and the guide shaft 7 by the screw 23, adjusting the tightening force of the screw 23 eliminates vertical play and reduces the sliding friction between the table support arm 301 and the guide shaft 7. The force can be adjusted. Therefore, when the motor 8 rotates, the rotation is transmitted to the spur gears 11, 12 via the spur gear 9, and the feed screw 10 fixed to the spur gear 11 rotates. An elastic pin 19 provided on the table drive arm 302 of the feed table 3 is elastically pressed into the thread groove of the feed screw 10, so that the feed table 3 moves toward the guide shaft 6 as the feed screw lO rotates. , 7. And feed screw 1
The rotation amount of 0 is detected by the encoder desk 20 provided at one end via the encoder detection circuit 21, and the rotation of the feed screw 10 can be controlled by the motor control circuit (not shown). 1
This allows access to a predetermined location on the optical desk. 1 (Insert the following statement in the 10th and 11th lines of page 12 of the 25 Specification. ``In order to shorten the access time, it is necessary to reduce the friction between the power transmission parts of each part''). In particular, the part of the feed table that pinches the guide shaft 7 is the most unstable, but by making it possible to adjust the pinching interval with respect to the guide shaft 7 as in the present invention, it can be stabilized without play. The dimensional accuracy and frictional force within the minimum allowable range are guaranteed.1 (3) The following statement is corrected from page 13, line 11 of the specification. FIG. 8 is a schematic plan view of a drive mechanism showing an embodiment of the present invention; FIG.
FIG. 0 is a perspective view and a sectional view of a main part of a mechanism for preventing rattling of the pickup. ■・・・・・・Pickup 2・・・・・・Reading lens 3・・・・・・Feeding table 16・・・α held 20・・・・... Encoder desk 131 ... Engagement pin 141 ... Tongue piece 160 ... Wide portion 161 ... Narrow width belt portion 162 ... Elongated hole space 163 ... Slit 302 ... Table drive arm 303...Table support arm 313...Upper bearing plate 323...Lower bearing plate Patent applicant Olympus Optical Industry Co., Ltd. Agent Patent attorney Takeshi Nara (1 person) J (4) No. 7 Figures 8, 9, and 10 are added as attached. 8. List of attached documents (1) Drawings 1 copy Figure 7 Figure 8 n Figure 10 Procedural amendment (voluntary) July 9, 1985 1. Indication of the case 1988 Patent Application No. 124802 2 , Title of the invention: Pick-up drive mechanism for optical information recording and reproducing device 3, Relationship to the case of the person making the amendment Patent applicant address: 2-43-2-4 Hatagaya, Shibuya-ku, Tokyo, Agent Q) Drawing 8, List of attached documents (1) Corrected specification (1 copy) (2) Amended drawings (1 copy) Corrected specification 1, Title of invention Pick-up drive mechanism for optical information recording and reproducing device 2, Claims (1) Along the guide shaft It has a pickup fixed to a moving feeding table, and an α belt fixed to a fixed base of the pickup feeding table, and the α belt is integrally fixed to a part of the final stage gear of the gear train of the drive system. A pickup drive mechanism for an optical information recording/reproducing device, characterized in that: (The pick-up drive mechanism according to claim 1, wherein the α-belt fixing base of the feeding table has a recessed relief formed by a step to ensure the tension of the α-belt. (■ The α belt is characterized by punching out a single metal belt and folding it back at a narrow belt part from a wide belt to form a single narrow belt part. The pickup drive mechanism according to claim 2. (4) The final gear shaft of the drive system is provided with an encoder disk for controlling the position of the pickup. The pickup drive mechanism according to claim 1. (c) The pickup drive according to claim 1, wherein the gear train used in the drive system is provided with a gear with a backlash prevention mechanism. Mechanism. (e) The backlash prevention mechanism is a mating gear connected by an elastic tongue protruding from one gear and an engagement pin protruding from the other gear. Pickup drive mechanism according to item 5. ■ The backlash prevention mechanism is characterized by a mating gear connected by a tongue protruding from one gear and a nine-ring engagement pin protruding from the other gear. The pickup drive mechanism according to claim 5. 3. Detailed Description of the Invention 1 Technical Field of the Invention The present invention relates to a pickup drive mechanism for an optical information recording and reproducing device. 1 Prior Art 1 In conventional CD (compact desk) players,
Since it is often used for playback only or by general users simply to listen to music, access speed is not so required. Therefore, since it was sufficient to read each track one by one and send it to a predetermined position, it was sufficient to send it 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 fast access speeds and high single-position performance are required.
A linear motor such as a CM (voice coil motor) is used, which has the problem of making the device large and expensive. [Object of the Invention] The present invention is small and inexpensive, has fast access speed,
It is an object of the present invention to provide a drive mechanism for an optical pickup for storing highly accurate information.

Summary of the Invention 1 The present invention provides a highly accurate and high-speed optical pickup drive mechanism by eliminating play in the power transmission drive system of the optical pickup drive mechanism. The pickup has a pickup fixed to a feed table that moves with the speed, and an α belt fixed to a fixed base of the pickup feed table, and the α belt is integrally fixed to a part of the final stage gear of the gear train of the drive system. In the pickup drive mechanism of the optical information recording and reproducing device, the final gear of the drive system is
A belt is provided, and a crash prevention mechanism is provided in the gear train of the drive system to eliminate misalignment of information positions between the encoder desk and the pickup, thereby obtaining a pickup drive mechanism with high access speed and high accuracy. [Examples] Hereinafter, the present invention will be specifically explained using examples. FIG. 1 is a plan view of an embodiment of the present invention, and FIG. 2 is a partially enlarged perspective view thereof. FIG. 3 is a sectional view showing the 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 4.5.
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 is fitted to the guide shaft 5 by an arm 6 having a substantially U-shaped guide groove so as to slide thereon. The feed table and the pickup are prevented from shaking vertically with respect to the guide shaft 4.degree. 5, and can be moved smoothly. 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 IO is rotatably attached to the gear 9 and has a backlash prevention mechanism described later. The pinion 12, which is made integral with the gear 9, drives the final gear 13, 14 of the gear train. This final stage gear 13.
14 also has a backlash prevention mechanism which will be described later. FIG. 4 is a row showing a known backlash prevention mechanism applied to the gears 9, 10 and 13, 14 described above, in which gear 14 is rotatable relative to gear 13. Gear 13
and 14 are engagement claws 101. and 14 of the coil spring 11, respectively.
102 engagement holes 140 and 130 are provided, and the two gears 13 and 14 are connected by a coil spring 11, overlapped, and prevented from being pulled out with an E ring 15 to form a mating gear. Therefore, gear 1
2, the gear 1 resists the elasticity of the coil spring 11.
By displacing and engaging gear 4 by an appropriate amount (for example, a rotation angle corresponding to 1 to 2 teeth) with respect to gear 13, a backlash prevention mechanism is constructed. This means that
Gear 9. The same applies to IO, so the explanation will be omitted. What is shown in FIG. 6 is an embodiment of the gear backlash prevention mechanism of the present invention. Two retaining pins 131 are provided protruding near the outer periphery of the gear 13' that transmits the driving force. The number of engagement pins can be set as required depending on the magnitude of the transmitted torque. Further, the tip end 132 of the shaft of the gear 13' has a diameter slightly larger than the inner diameter 142 of the gear 14', and is provided with a plurality of grooves. An elastic tongue piece 141 is provided on the gear 14' in a protruding manner at a position corresponding to the engaging pin 131 of the gear 13'. By overlapping the gear 13' and the gear 14' with the retaining pin 131 located on one side of the tongue piece 141, the tip 1332 of the gear 13' is displaced by the kerf, and the inner diameter of the gear 14' is After passing through 142, it returns again due to its elastic force to form a pull-out stop, and gears 13' and 14' constitute a mating gear. Therefore, when the gear 14' is engaged with another gear, the backlash prevention mechanism is created by displacing the gear 14' by an appropriate amount (for example, a rotation angle corresponding to 1 to 2 teeth) and engaging the gear 13'. is constructed. The final stage gear 13 of the gear train provided with such a backlash prevention mechanism has an α belt 16 attached to a pulley portion 133 integral therewith with screws or the like. This α
Both ends of the belt 16 are fixed to α-belt fixing bases 17 and 18 fixed to the feed table 3, respectively, and the α-belt fixing base has steps 170 and 180 inward to ensure the tension of the α-belt. A relief of the recess is formed. That is, the alpha belt 16 wound around the pulley part 133 can always move the feed table 3 with a constant tension without coming into contact with the fixed base due to the relief part created by the step. In addition, in order to constantly apply tension to the α belt and to provide appropriate tension during assembly work to facilitate assembly, a belt fixing stand 17 is provided.
, 18 are provided with horizontally long through-mounting holes 173 and 183, so that they can be slidably attached to the two belt fixing bases 17 and 18. By press-fitting the α-belt 16, tension can be constantly applied to the α-belt 16. To attach the α belt to the pulley portion 133 of the gear 13,
First, the α belt 16 is wound around the pulley part 133, and the fourth
As shown in the figure, after fixing with machine screws etc., both ends of the α belt are fixed to fixing bases 17 and 18. The fixed base 17.13 also has a guide wall 171 for the α belt.
．． 172 and 181.182 are provided. When the α-belt is attached to the fixed base, the two are installed completely parallel to each other without tilting, and a device is used to prevent the tension applied to the α-belt from shifting. FIG. 5 is an explanatory diagram of the shape of an α belt, in which FIG. 5 (A) shows a conventional α belt, and FIG. As shown in FIG. 5(A), the conventional α belt has a wide portion 160 on one side, and a long hole space 162 is formed inside, and the width of the long hole space is on the opposite side of the α belt. It is slightly wider than the narrower belt portion 161, so that the two can cross each other. However, when considering the material required to manufacture the α belt, as shown in the figure, a fairly long piece must be punched out, and the material in the long hole space 162 must be wasted, which increases the material cost. It has the disadvantage of being relatively expensive. Therefore, the α belt used in the present invention has one metal belt with one hollow slit, as shown in FIG. 5(b).
63 is punched out, and the remaining metal portion is folded back as shown in FIG. 5(C) to form a narrow belt portion 161. That is, by punching out a single metal belt, a narrow belt portion is punched out from a wide belt and folded back to form a single narrow belt portion. Therefore,
The α-belt used in the present invention can be manufactured from a material with half the length compared to conventional ones, and the folded part is overlapped and screwed to the pulley of the gear, so there is a problem with strength. does not occur at all. 7 and 8 are an exploded perspective view and a sectional view showing an embodiment other than the arm 6 shown in FIG. 1. That is, the arm 6 shown in FIG. 1 is configured to operate by fitting the arm 6 having a substantially U-shaped guide groove into the guide shaft 5, but the arm 6 shown in FIGS. The arm 303 of the embodiment forms a substantially U-shaped sandwiched portion between an upper bearing plate 313 and a lower bearing plate 323.
The upper and lower bearing plates are each formed with inclined surfaces 305 and 306 in the direction of movement with respect to the guide shaft 5, in order to reduce friction with the guide shaft 5 caused by the edges. 305 is a hole for the screw 53 provided on the upper bearing plate,
The lower bearing plate 306 is provided with a female screw hole 304 for the screw 53. Reference numeral 52 denotes a spring for elasticity adjustment, which is press-fitted between the upper bearing plate 313 and lower bearing plate 323 of the arm 303 as shown in FIG. By adjusting the tightening force of the arm 303, the sliding friction force between the arm 303 and the guide shaft 5 can be adjusted without vertical play. 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 20 to a part of the final stage gear of the gear train of the drive system. That is, since the driving force of the motor 7 rotates the encoder desk 20 through the gear train 8 to 14, the feed table 3 is moved by the α belt fixed to the pulley of the final stage gear, and the pickup 1 is moved to the guide shaft. It is possible to access a predetermined position on the optical desk by moving it along 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 on the way to the stage gear, and since the encoder is installed at the final stage of the drive system, the encoder controls the pickup position without being affected by the rigidity of the transmission mechanism. This makes it possible to improve the feeding accuracy and ensure its reproducibility, as well as to obtain a small and inexpensive peak/cup drive mechanism. In the embodiments 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 is installed in the drive system. No matter where the pickup is installed, the information position of the pickup and the position detected by the encoder will not deviate, and highly accurate information position control can be performed. Furthermore, by using a DC brushless motor as the drive motor 7, it is possible to obtain a servo drive circuit that is free from noise and cogging (torque unevenness), has a long life, and is easy to design. 4. Brief description of the drawings Fig. 1 is a plan view of an embodiment of the present invention, Fig. 2 is a partially enlarged perspective view thereof, Fig. 3 is a sectional view showing the gear train, and Fig. 4 is an explanation of the backlash prevention mechanism. FIG. 5 is an explanatory diagram of the shape of the α belt. FIG. 5 (A) shows the conventional α belt, and FIGS. 5 (B) and (C) show the α belt used in the present invention. FIG. 6 is a perspective view showing one embodiment of the backlash prevention mechanism of the present invention, and FIGS. 7 and 8 are an exploded perspective view and a sectional view showing an embodiment other than the arm in FIG. 1. 1...Pickup 2...Reading lens 3...Feeding table 4.5...Guide shaft 8.303...Arm 7...Motor 8-14...Gear train 11... Coil spring 13.1'4...Last gear of gear train 16...α belt 20...Encoder desk 131...Engagement pin 141...Language piece 160...Wide portion 161...・Narrow belt portion 162...Elongated hole space 163...Slit patent applicant Olympus Optical Industry Co., Ltd. Agent Patent attorney Takeshi Nara Figures 1, 2, 3, 4, 5 Figure (a) Figure 6 Figure 7 Figure 8 ≧

Claims (8)

[Claims] (1) It has a pickup fixed to a feed table that moves along a guide shaft, and an α belt fixed to a fixed base of the pickup feed table, and the α belt is connected to the final stage gear of the gear train of the drive system. A pickup drive mechanism for an optical information recording/reproducing device, characterized in that the pickup drive mechanism is integrally fixed to a part. (2) The pickup drive mechanism according to claim 1, wherein the α-belt fixing base of the feed table is provided with a recessed relief by a step to ensure the tension of the α-belt. (3) The alpha belt is characterized by punching out a narrow belt part from a wide belt and folding it back to form a single narrow belt part by hollowing out a single metal belt. A pickup drive mechanism according to claim 2. (4) The pickup drive mechanism according to claim 1, wherein an encoder disk for controlling the position of the pickup is provided on the final stage gear shaft of the drive system. (5) The pickup drive mechanism according to claim 1, wherein the gear train used in the drive system is provided with a gear with a backlash prevention mechanism. (6) The pickup drive mechanism according to claim 5, wherein the backlash prevention mechanism is a mating gear in which both gears are connected by a coil spring provided between the two gears. (7) The backlash prevention mechanism is a mating gear connected by an elastic tongue protruding from one gear and an engagement pin protruding from the other gear. Pickup drive mechanism as described in section. (8) The backlash prevention mechanism is a mating gear connected by a tongue protruding from one gear and an elastic engagement pin protruding from the other gear. Pickup drive mechanism as described in section.