CN1081379C - Disk player - Google Patents

Abstract

A disk player includes a deck base, a deck plate elastically coupled to the deck base, a buffering member interposed between the deck base and the deck plate, a spindle motor coupled to the deck plate and having a stator, a rotor and a rotational shaft, a turntable installed at the rotational shaft, a clamper, and an optical pickup for recording/reproducing information on/from the disk. A self-compensating dynamic ring balancer is coupled to the spindle motor and positions the center of gravity thereof opposite to that of the disk with respect to the rotational shaft during rotation of the disk. Therefore, the revolution of the rotational shaft of the spindle motor due to the eccentric center of gravity of the disk can be reduced.

Description

CD drive

The present invention relates to a disc drive, in particular to a disc drive equipped with a self-compensating dynamic ring balancer in order to limit the internal vibration caused by the eccentricity of the center of gravity of the disc.

A CD player can record on and/or reproduce information from a recording medium such as a CD, CD ROM or DVD. The jukebox should also protect the disc and optical head from external shocks and internal vibrations.

As shown in Figure 1, a traditional optical disk drive includes a base plate seat 10 that is hinged with the housing (not shown) and can rotate around a pivot in the vertical direction, a base plate 20 that is connected with the base plate base 10, a A spindle motor 21 installed on the bottom plate 20 to provide rotational power to the optical disk 1, a turntable 23 connected to the rotating shaft 22 of the spindle motor 21 to support the optical disk 1, and a turntable 23 installed in the housing opposite to the turntable 23 A compactor 40 for compacting and positioning the optical disc 1 on the turntable 23, and an optical head 25 connected to the bottom plate 20 and movable across the optical disc 1 for recording or playing.

This optical disk drive is also equipped with a shock absorbing element 30 between its chassis base 10 and the base plate 20 to prevent external vibrations from being directly transmitted to the base plate 20 , the spindle motor 21 and the optical head 25 through the chassis base 10 . The damping element is made of a material such as soft rubber or polyurethane in order to sufficiently damp external vibrations.

The optical disc player with the above structure can effectively protect the optical disc 1 and the optical head 25 from external vibration. However, it does not solve the problem of attenuation of the internal vibration caused by the eccentricity of the center of gravity of the disc during the rotation of the spindle motor 21 . Here, the eccentricity of the center of gravity of the optical disc is caused by misalignment between the center of rotation and the center of gravity of the optical disc 1 due to errors in the manufacturing process of the optical disc 1 . In this way, the rotating shaft 22 of the spindle motor 21 will rotate due to the rapid rotation.

In low speed modes like 1x or 2x, this rotation of the spindle motor shaft does not cause much of a problem. However, in the case of high speed modes such as 6x, 8x, 12x or 24x speed modes, the influence of this rotation of the spindle motor becomes serious, and it is even difficult to record and reproduce information.

Considering the above-mentioned problems, in traditional high-speed optical disc drives, methods such as increasing the mass of the base plate on which the spindle motor is installed or increasing the stiffness of the shock-absorbing element are usually used to reduce the movement of the base plate caused by the eccentric center of gravity of the optical disc. However, increasing the mass of the chassis has no effect on high-speed rotation. Also, when the rigidity of the damping member increases, it becomes impossible to effectively damp vibration or impact from the outside.

The object of the present invention is to provide an optical disk player in which the internal vibration caused by the eccentric center of gravity of the optical disk can be eliminated fundamentally by using a self-compensating dynamic ring balancer.

In order to achieve the above object, the optical disc drive provided according to the present invention includes a base plate, a base plate elastically connected to the base plate, a shock-absorbing element placed between the base plate and the base plate to protect the base plate from external impact, installed on the base plate toward The disc provides the rotating power of the spindle motor. The motor has a stator fixed on the bottom plate, and is equipped with a rotor that is driven to rotate through the electric interaction force between the stator and the stator. The rotating shaft extends from the rotor. The jukebox also includes a turntable mounted on the axis of rotation to hold the disc, a clamper that compresses and positions the disc on the turntable, and an optical head mounted on the chassis that moves across the disc for recording on the disc Or reproduce information from an optical disc, and a self-compensating dynamic ring balancer connected to the spindle motor. During the rotation of the optical disc, the center of gravity of the balancer and the center of gravity of the optical disc are opposed to each other with respect to the axis of rotation, resulting in a reduction in the Rotation of the spindle motor rotation shaft due to the eccentric center of gravity.

The above objects and advantages of the present invention will become more apparent by describing the preferred embodiments in detail with reference to the accompanying drawings. These drawings are:

Fig. 1 is an exploded perspective view of a conventional optical disc drive;

2 is an exploded perspective view of an optical disc drive according to an embodiment of the present invention;

Figures 3a to 3c show the relationship between the eccentricity of the center of gravity of the optical disc and its center of rotation at different rotational speeds relative to the rotational axis of the optical disc;

Fig. 4 is a sectional view of a self-compensating dynamic ring balancer according to a preferred embodiment of the present invention;

Fig. 5 is a schematic perspective view of the self-compensating dynamic ring balancer shown in Fig. 4 without a turntable;

Fig. 6 is a sectional view of a self-compensating dynamic ring balancer according to another preferred embodiment of the present invention;

7 is a cross-sectional view of a self-compensating dynamic ring balancer according to yet another preferred embodiment of the present invention; and

8a and 8b respectively show the relationship between the eccentricity of the center of gravity of the disc and the center of rotation of the disc drive with a self-compensating dynamic ring balancer at different rotational speeds relative to the rotational axis of the disc according to the present invention.

As shown in Figure 2, the CD player according to the preferred embodiment of the present invention includes a base plate 50, a base plate 60 elastically connected to the base base 50, a shock absorbing element 70 placed between the base base 50 and the base plate 60, mounted on the base plate 60 The spindle motor 90 on the turntable 63, the optical head 65, the compactor 80 that keeps the optical disc 1 on the turntable 63, and the self-compensating dynamic ring balancer 200, which is used to limit the spindle caused by the eccentricity of the disc center of gravity. Rotation of the rotary shaft 92 of the motor 90 .

The base plate seat 50 is hinged to one side of the housing (not shown in the figure), and can rotate up and down around the pivot. The base plate 60 is subjected to an impact force generated outside the base plate base 50 , and the impact force is damped by the shock absorbing member 70 . Therefore, it is preferable to reduce the rigidity of the shock absorbing member 70 and lower the center of gravity of the bottom plate 60 . The spindle motor 90 can provide the rotational force to drive the optical disc to rotate. The turntable 63 is installed concentrically with the rotating shaft 92 of the spindle motor 90, and the optical disc 1 is placed on the upper surface of the turntable 63 during operation. The presser 80 is facing the turntable 63 to prevent unnecessary movement of the optical disc 1 after it is in place. Here, the spindle motor 90 includes a stator (not shown in the figure) and a rotor (not shown in the figure) paired with the stator, and has a rotating shaft 92 . The rotor is driven to rotate by an external current. When the rotor rotates, the turntable 63 fixed on the rotating shaft 92 also rotates, thereby driving the optical disc 1 and the compactor 80 to rotate together.

Referring to Figures 3a to 3c, the relationship between the eccentricity of the disc's center of gravity and its center of rotation at different rotational speeds of the disc will be described.

FIG. 3a shows the orbital motion and rotational motion of the optical disc 1 when the rotational speed of the rotating shaft 92 of the spindle motor 90 is equal to or less than the natural frequency of the base plate 60. As shown in FIG. Here, the magnitude of the natural frequency depends on the modulus of elasticity of the damping element 70 and the mass of the chassis 60 and other elements 63 , 65 and 90 mounted on the chassis 60 . The natural frequency characterizes the vibration frequency in the horizontal direction (ie, the direction parallel to the plane of the optical disc). As shown in the figure, when the eccentric center of gravity _me of the optical disc 1 is at a position _P1 apart from its rotational center _C1 by a predetermined distance, the rotational center C1 of the optical disc ₁ rotates around the rotational center C to a position _C2 , C ₃ and C ₄ . The positions of the center of gravity _me of the eccentricity of the optical disc 1 corresponding to each of the rotation centers _C2 , _C3 and _C4 are at _P2 , _P3 and _P4 , respectively. Here, the respective positions P ₁ , P ₂ , P ₃ and P ₄ of the center of _gravity me of the center of rotation C and the eccentricity of the optical disc 1 are mutually relative to the respective rotational centers C ₁ , C ₂ , C ₃ and C ₄ of the optical disc 1. opposite.

FIG. 3b shows the orbital motion and rotational motion of the optical disc 1 when the rotational speed of the rotary shaft 92 of the spindle motor 90 is similar to the above-mentioned natural frequency. As shown in the figure, the respective positions P ₁ , P ₂ , P ₃ and P ₄ of the _eccentric center of gravity me of the center of rotation C and the optical disc 1 are relative to the respective rotational centers C ₁ , C ₂ , C ₃ and C ₄ of the optical disc 1. Said to be perpendicular to each other.

What Fig. 3 c represented is the orbital motion and the rotational motion of optical disc 1 when the rotational speed of the rotating shaft 92 of spindle motor 90 is greater than above-mentioned natural frequency, and the normal rotational speed of recording and reproducing information material from optical disc just belongs to this kind Condition. At this time _, the respective positions P ₁ , P ₂ , P ₃ and _{P 4} of the _eccentric center of _{gravity me} between the center of rotation _C and the optical disc 1 are located at same direction.

The present invention is characterized in that the self-compensating dynamic ring balancer 200 reduces eccentricity by utilizing the relationship between the center of rotation and the center of gravity of an eccentric optical disc.

The self-compensating dynamic ring balancer 200 is mounted on the rotor 93 (see FIG. 4 ) or the rotating shaft 92, which is the rotating element of the spindle motor 90, and has a center of gravity that changes while rotating.

As shown in FIG. 4 , the spindle motor 90 mounted on the bottom plate 60 drives the turntable 63 (see FIG. 2 ) connected to the rotating shaft 92 to rotate.

The spindle motor 90 includes a motor base 91 , a rotating shaft 92 , a rotor 93 , a stator 97 , and bearings 101 and 102 . The motor base 91 is connected to the bottom plate 60 and has a through hole 91a thereon. The rotary shaft 92 and the bearings 101 and 102 are fitted in the through hole 91a.

The rotor 93 is fixed at one end of the rotating shaft 92, and has a casing 94 surrounding a stator 97, and a magnet 95 is fixed on the inner surface of the casing 94. Here, there is a fixing member 96 at the connecting portion between the housing 94 and the rotating shaft 92 for preventing the rotating shaft 92 from slipping out of the housing 92 or idling.

The stator 97 is fixed on the bottom surface of the motor base 91 and includes an iron core 98 facing the magnet 95 . The coil 99 surrounds the core 98 . Bearings 101 and 102 are installed between the through hole 91a and the rotary shaft 92 and support the rotary shaft in the radial direction and the axial direction. The pair of bearings 101 and 102 are spaced apart by a predetermined distance when mounted in the through hole 91a. That is, the first bearing 101 has an inner ring tightly fitted on the rotary shaft 92 and an outer ring press-fitted in the through hole 91a, so that the radial and axial movements of the rotary shaft 92 are restricted. The second bearing 102 is embedded in the through hole 91a and can slide, thereby preventing the rotation shaft 92 from tilting. The elastic member 103 is placed in the through hole 91 a between the first bearing 101 and the second bearing 102 to attenuate the rotational vibration transmitted from the rotor 93 to the motor base 91 . Considering the positioning accuracy required for high-speed rotation, the bearings 101 and 102 are preferably metal bearings. However, different types of bearings can also be used, such as ball bearings or aerodynamic bearings.

Referring now to Figures 4 to 6 for the first self-compensating dynamic ring balancer according to the present invention

Embodiment makes an explanation.

As shown in FIGS. 4 and 5 , the self-compensating dynamic ring balancer includes at least a pair of rings 210 surrounding the axis of rotation 92 . Each ring 210 is circular, and when the rotating shaft 92 rotates due to internal vibration during rotation, the ring 210 rotates around the rotating shaft 92 according to the speed of rotation, and the rotation of the rotating shaft is restricted at this moment. The principle of rotation will be discussed later. Each ring 210 is sleeved on the rotating shaft 92, and is between the base plate 60 and the turntable 63, and its inner diameter is smaller than the diameter of the turntable 63, so as to prevent the ring 210 from being thrown out from the rotating shaft 92 during operation.

In addition, as shown in FIG. 6 , the self-compensating dynamic ring balancer 200 may also include a protection element fixed on the rotating shaft 92 to protect the ring 210 . The protection element prevents the ring 210 from coming into contact with the fixed part (eg, the bottom plate 60 ) when it is rotated. As shown, the protective element is preferably a housing 220 mounted on the rotating shaft 92 and surrounding the ring 210 . The outer cover 220 has a cover body 221 mounted on the rotating shaft 92 and a cover cover 222 fitted to the opening portion of the cover body 221 . In addition, the protective element can also be a bracket (not shown in the figure) installed on the rotating shaft 92 to support the lower part of the ring 220 .

Referring again to FIG. 7, a second embodiment of the self-compensating dynamic ring balancer according to the present invention will be described.

As shown in the figure, the self-compensating dynamic ring balancer 200 includes a pair of rings 210 inserted in the housing 94 to move around the rotor 93, and a protection member supporting the rings 210. The protective element is mounted on the housing 94 to prevent the ring 210 from being thrown out of the housing.

The protective element is preferably a housing 230 surrounding the ring 210, as shown. The outer cover 230 has a cover body 231 mounted on the casing 94 and a cover cover 232 fitted to the opening portion of the cover body 231 . In addition, the protective element can also be a bracket (not shown) installed on the housing 94 to support the lower part of the ring 210 .

Although the self-compensating dynamic ring balancer 200 is shown in FIGS. 4-7 as a pair of rings, three or more rings may also be used.

As mentioned above, the self-compensating dynamic ring balancer 200 is preferably made of non-magnetic material so as to exclude the influence of magnetic attraction in the vicinity of the balancer. That is to say, the ring and the protective element can be manufactured from one of the following groups of materials. These materials are: tungsten carbide WC, copper beryllium alloy steel CuBe, nickel base alloy C-276, silicon nitride Si ₃ N ₄ , zirconia ZrO ₂ , austenitic series steel YHD50, non-magnetic metals such as SUS300, SUS304 and SUS316 , and ceramic or synthetic resin.

In addition, the ring and/or the protective member are preferably made of a material that is not oxidized such as SUS300, ceramics, and synthetic resin or a material with an anti-oxidation coating. The material with anti-oxidation coating can be selected from carbon steel or chrome steel as the base and plated with zinc or nickel chrome coating.

Next, a description will be given of the operation mechanism for reducing the influence of the eccentricity of the center of gravity of the optical disc according to the present invention with reference to FIGS. 2, 8a and 8b.

When the _number of revolutions of the optical disc 1 is equal _to or less than the natural frequency, as _shown in FIG. The position P' _i (i=1, 2, 3 and 4) of the center of gravity of 210 is opposite to the position C _i (i=1, 2, 3 and 4) of the center of rotation C relative to the rotation axis 92 . At this time, the radius of gyration of the rotary shaft 92 becomes large.

However, when the optical disc 1 rotates at a normal speed and its number of revolutions is much larger than the natural frequency, as shown _in Figure 8b, the position P _i (i=1, 2, 3 and 4) Relative to the position C _i of the rotation axis 92, it is on the same side, while the position P' _i (i=1, 2, 3 and 4) of the compensation center of gravity m _c is on the other side due to the centrifugal force. In this way, the unbalanced state caused by the eccentricity of the center of gravity of the optical disc 1 can be compensated, and the radius of gyration of the rotating shaft 92 will be greatly reduced. Therefore, the internal vibration force of the bottom plate 60 due to the eccentricity of the center of gravity _me of the optical disk 1 is damped.

As described above, according to the optical disk player of the present invention using the self-compensating dynamic ring balancer, the internal vibration can be effectively restricted when the center of gravity of the optical disk used therein exhibits a large eccentricity. In addition, the use of a less rigid shock-absorbing element in the optical disc drive can also effectively alleviate external shocks.

Claims (8)

1. A CD player has a base plate, a base plate elastically connected to the base plate, placed between the base plate base and the base plate to protect the base plate from external impact shock absorbing elements, installed on A spindle motor on the bottom plate that provides rotational power to the optical disk, the spindle motor has a stator fixed on the bottom plate, and is equipped with a rotor that is driven to rotate through the electric interaction force between the stator and the stator, The rotating shaft extending from the rotor is installed on the rotating shaft to support the turntable of the disc, and the compactor for pressing the disc and positioning it on the turntable is installed on the bottom plate An optical head, which can move across the optical disc to record or reproduce information from the optical disc, is characterized in that the optical disc drive includes a self-compensating dynamic ring balancer connected to the spindle motor, and when the optical disc rotates During this period, the center of gravity of the balancer and the center of gravity of the disc are opposed to each other with respect to the rotation shaft, reducing the rotation of the rotation shaft of the spindle motor caused by the eccentricity of the center of gravity of the disc. 2. The optical disc player according to claim 1, wherein said self-compensating dynamic ring balancer has at least one pair of rings sleeved on said rotating shaft and movable around said rotating shaft. 3. The optical disc player according to claim 2, wherein said self-compensating dynamic ring balancer further comprises a protection element connected with said rotating shaft to prevent said ring from contacting said The stator or the base plate are in contact. 4. The optical disc player according to claim 1, wherein said self-compensating dynamic ring balancer comprises: at least one pair of rings fitted over and movable around said rotor; and A protective element connected to the rotor for supporting the ring and preventing the ring from being thrown from the rotor. 5. The optical disk drive according to any one of claims 1 to 4, wherein the self-compensating dynamic ring balancer is made of a material that cannot be oxidized and will not be corroded. 6. The optical disk drive according to claim 5, wherein said self-compensating dynamic ring balancer is made of a material selected from the group consisting of SUS300, ceramics and synthetic resin. 7. The optical disk drive according to any one of claims 1 to 4, wherein the self-compensating dynamic ring balancer is coated with an anti-oxidation coating on its outer surface. 8. The optical disk drive according to claim 7, wherein the material with the anti-oxidation coating can be selected from carbon steel or chromium steel as the base and coated with zinc or nickel-chromium coating.

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