Disk player, and turntable incorporating self-compensating dynamic balancer, clamper incorporating self-compensating dynamic balancer and spindle motor incorporating self-compensating dynamic balancer adopted for disk player

Abstract

A disk player having a self-compensating dynamic balancer which can limit internal vibrations generated by an eccentric center of gravity of a disk, and a turntable, a clamper and a spindle motor which incorporate a self-compensating dynamic balancer. The self-compensating dynamic balancer is formed integrally with rotating members in a disk player; that is, a turntable, a clamper and/or a rotor of a spindle motor. The self-compensating dynamic balancer includes at least one race which is integrally formed with the rotating member and rotates around a rotational shaft, a mobile unit which is located in the race to be capable of moving, and a cover member for covering an opening of the race. Thus, internal vibrations occurring due to the eccentric center of gravity of the disk can be effectively limited by the self-compensating dynamic balancer in which the mobile unit is disposed far away from the center of orbital rotation by a centrifugal force during rotation thereof.

What is claimed is:  
     
         1 . A disk player comprising: 
 a deck base;    a deck plate elastically coupled to said deck base;    at least one buffering member interposed between said deck base and said deck plate for protecting said deck plate from external impacts;    a spindle motor having a rotational shaft and being mounted to said deck plate for providing a rotational force to a disk;    a turntable mounted to said rotational shaft of said spindle motor for accommodating the disk;    a clamper for holding the disk in place on said turntable;    an optical pickup installed at said deck plate to be capable of moving across the disk; and    a self-compensating dynamic balancer mounted to at least one among members which are rotated by the rotational force provided by said spindle motor, the center of gravity of said self-compensating dynamic balancer being located opposite to that of said disk with respect to said rotational shaft of said spindle motor by a centrifugal force generated during rotation of the disk.    
     
     
         2 . A disk player as claimed in  claim 1 , wherein said self-compensating dynamic balancer includes a hollow tube and a mobile unit which is disposed in said hollow tube so as to move freely therein.  
     
     
         3 . A disk player as claimed in  claim 2 , wherein said hollow tube is formed of a body having a race in which said mobile unit is disposed and a cover member which covers said race by being coupled to said body.  
     
     
         4 . A disk player as claimed in  claim 3 , wherein said mobile unit includes at least a single rigid body which can move in said race.  
     
     
         5 . A disk player as claimed in  claim 4 , wherein said rigid body is formed into a shape selected from the group consisting of a spherical body which can roll inside said race, a cylindrical body which can roll with an outer circumferential surface thereof contacting the inner surface of an outer circular wall of said race, a truncated conic body which can roll with an outer circumferential surface thereof contacting a bottom surface of said race, and a fan-shaped block which can slide while being in contact with one of the bottom surface and the outer circular wall of said race.  
     
     
         6 . A disk player as claimed in  claim 4 , wherein said rigid body is formed of a non-magnetic material in order to avoid being influenced by a magnetic force.  
     
     
         7 . A disk player as claimed in  claim 6 , wherein said rigid body is formed of a substance selected from the group consisting of tungsten carbide (WC), beryllium steel (CuBe), Hastelloy C-276, silicon nitride (Si 3 N 4 ), zirconia (ZrO 2 ), brass, aluminum, austenite-series steel YHD50, a non-magnetic metal such as SUS300, SUS304 and SUS316, ceramic and a synthetic resin.  
     
     
         8 . A disk player as claimed in  claim 4 , wherein said rigid body is formed of a non-oxidizing substance which does not corrode.  
     
     
         9 . A disk player as claimed in  claim 8 , wherein said rigid body is formed of a substance selected from the group consisting of SUS300, ceramic and a synthetic resin.  
     
     
         10 . A disk player as claimed in  claim 6 , wherein an outer circumferential surface of said rigid body is anti-oxidation coated.  
     
     
         11 . A disk player as claimed in  claim 10 , wherein said anti-oxidation coating is formed of a material selected from the group consisting of zinc and nickel-chromium plated over a base material of carbon steel or chromium steel.  
     
     
         12 . A disk player as claimed in  claim 3 , wherein said mobile unit includes a fluid which is injected into said race to be capable of moving, said fluid being located such that the center of gravity thereof is located opposite to that of the disk with respect to said rotational shaft by a centrifugal force generated during rotation of said hollow tube.  
     
     
         13 . A disk player as claimed in  claim 2 , wherein the cross section of said hollow tube in which said mobile unit is located has a shape selected from the group consisting of a rectangular shape, an oval shape having a longer axis in a latitudinal direction with respect to said rotational shaft, and an inwardly bulging polygonal shape in which a portion of each side contacting said mobile unit bulges inward.  
     
     
         14 . A disk player as claimed in  claim 2 , wherein said rigid body is formed of a non-magnetic material in order to avoid being influenced by a magnetic force.  
     
     
         15 . A disk player as claimed in  claim 14 , wherein said tube is formed of a substance selected from the group consisting of tungsten carbide (WC), beryllium steel (CuBe), Hastelloy C-276, silicon nitride (Si 3 N 4 ), zirconia (ZrO 2 ), brass, aluminum, austenite-series steel YHD50, a non-magnetic metal such as SUS300, SUS304 and SUS316, ceramic and a synthetic resin.  
     
     
         16 . A disk player as claimed in  claim 2 , wherein said hollow tube is formed of a non-oxidizing substance which does not corrode.  
     
     
         17 . A disk player as claimed in  claim 16 , wherein said hollow tube is formed of a substance selected from the group consisting of SUS300, ceramic and a synthetic resin.  
     
     
         18 . A disk player as claimed in  claim 2 , wherein the surface of said hollow tube facing said mobile unit is anti-oxidation coated.  
     
     
         19 . A disk player as claimed in  claim 18 , wherein said anti-oxidation coating is formed of one selected from the group consisting of zinc and nickel-chromium plated over a base material of carbon steel or chromium steel.  
     
     
         20 . A disk player as claimed in  claim 1 , wherein said self-compensating dynamic balancer includes at least two circular tubes which are arranged to be concentric and adjacent to each other and have mobile units located in the respective tubes.  
     
     
         21 . A disk player as claimed in  claim 20 , wherein the mobile unit of each of the respective tubes is a rigid body which can one of roll and slide in the respective tubes.  
     
     
         22 . A disk player as claimed in  claim 21 , wherein weights of said rigid bodies located in the respective tubes differ from each other.  
     
     
         23 . A disk player as claimed in  claim 1 , wherein said self-compensating dynamic balancer includes a support plate fixed to said rotational shaft of said spindle motor and at least one pivoting plate hinge-coupled to said support plate parallel to each other.  
     
     
         24 . A disk player as claimed in  claim 1 , wherein said self-compensating dynamic balancer is formed to incorporate said turntable.  
     
     
         25 . A disk player as claimed in  claim 24 , wherein said turntable includes a placing member, which has a coupling hole coupled to said spindle motor and a placing surface on which the disk is placed, and a coupling protrusion which is formed to project from said placing member and the center hole of said disk is fittingly coupled thereto, and 
 wherein said self-compensating dynamic balancer includes a circular race which is formed in said placing member and rotates around the center of rotation of said placing member, a mobile unit including a rigid body which is disposed in said circular race, and a cover member which is coupled to an opening of said race to cover said race.    
     
     
         26 . A disk player as claimed in  claim 25 , further comprising a fluid injected into said race to be capable of moving.  
     
     
         27 . A disk player as claimed in  claim 25 , wherein said turntable further comprises an installation groove formed in said coupling protrusion and a magnet, which is inserted in said installation groove, for fixing the disk placed on said placing surface by a magnetic attractive force with said clamper.  
     
     
         28 . A disk player as claimed in  claim 25 , wherein the cross-section of said race in which said mobile unit can roll has a shape selected from the group consisting of a rectangular shape, an oval shape having a longer axis in a latitudinal direction with respect to said rotational shaft, and an inwardly bulging polygonal shape in which a portion of each side contacting said mobile unit bulges inward.  
     
     
         29 . A disk player as claimed in  claim 25 , wherein said rigid body is formed of a non-magnetic material in order to avoid being influenced by a magnetic force.  
     
     
         30 . A disk player as claimed in  claim 29 , wherein said rigid body is formed of a substance selected from the group consisting of tungsten carbide (WC), beryllium steel (CuBe), Hastelloy C-276, silicon s nitride (Si 3 N 4 ), zirconia (ZrO 2 ), brass, aluminum, austenite-series steel YHD50, a non-magnetic metal such as SUS300, SUS304 and SUS316, ceramic and a synthetic resin.  
     
     
         31 . A disk player as claimed in  claim 25 , wherein said rigid body is formed of a non-oxidizing substance which does not corrode.  
     
     
         32 . A disk player as claimed in  claim 31 , wherein said rigid body is formed of a substance selected from the group consisting of SUS300, ceramic and a synthetic resin.  
     
     
         33 . A disk player as claimed in  claim 25 , wherein an outer circumferential surface of said rigid body is anti-oxidation coated.  
     
     
         34 . A disk player as claimed in  claim 33 , wherein said anti-oxidation coating is formed of a material one selected from the group consisting of zinc and nickel-chromium plated over a base material of carbon steel or chromium steel.  
     
     
         35 . A disk player as claimed in  claim 25 , wherein a cross-section formed by said placing member and said cover member in which said mobile unit is located has a shape selected from the group consisting of a rectangular shape, an oval shape having a longer axis in a latitudinal direction with respect said rotational shaft, and an inwardly bulging polygonal shape in which a portion of each side contacting said rigid body bulges inward.  
     
     
         36 . A disk player as claimed in  claim 25 , wherein said placing member and said cover member are formed of a non-magnetic material in order to avoid being influenced by a magnetic force.  
     
     
         37 . A disk player as claimed in  claim 36 , wherein said placing member and said cover member are formed of a substance selected from the group consisting of tungsten carbide (WC), beryllium steel (CuBe), Hastelloy C-276, silicon nitride (Si 3 N 4 ), zirconia (ZrO 2 ), brass, aluminum, austenite-series steel YHD50, a non-magnetic metal such as SUS300, SUS304 and SUS316, ceramic and a synthetic resin.  
     
     
         38 . A disk player as claimed in  claim 25 , wherein said placing member and said cover member are formed of a non-oxidizing substance which does not corrode.  
     
     
         39 . A disk player as claimed in  claim 38 , wherein said placing member and said cover member are formed of a substance selected from the group consisting of SUS300, ceramic and a synthetic resin.  
     
     
         40 . A disk player as claimed in  claim 25 , wherein a surface of said placing member and said cover member facing said rigid body is anti-oxidation coated.  
     
     
         41 . A disk player as claimed in  claim 40 , wherein said anti-oxidation coating is formed of a material selected from the group consisting of zinc and nickel-chromium plated over a base material of carbon steel or chromium steel.  
     
     
         42 . A disk player as claimed in  claim 24 , wherein said turntable includes a placing member, which has a coupling hole coupled to said spindle motor and a placing surface on which a disk is placed, and a coupling protrusion which is formed so as to project from said placing member and a center hole of said disk is fittingly coupled thereto, and 
 wherein said self-compensating dynamic balancer includes at least two circular races which are formed in said placing member and rotate around the rotation center of said placing member, mobile units including rigid bodies disposed in the respective circular races, and a cover member which is coupled to an opening of each of said races to cover said races.    
     
     
         43 . A disk player as claimed in  claim 42 , wherein weights of said rigid bodies located inside each of said races differ from each other.  
     
     
         44 . A disk player as claimed in  claim 42 , wherein a fluid is injected into at least one of said races.  
     
     
         45 . A disk player as claimed in  claim 42 , wherein said turntable further includes an installation groove formed in said coupling protrusion and a magnet which is inserted in said installation groove for fixing the disk placed on said placing surface by a magnetic attractive force with said clamper.  
     
     
         46 . A disk player as claimed in  claim 24 , wherein said turntable includes a placing member, which has a coupling hole coupled to said spindle motor and a placing surface on which a disk is placed, and a coupling protrusion which is formed to project from said placing member and the center hole of said disk is fittingly coupled thereto, and 
 wherein said self-compensating dynamic balancer includes a circular race which is formed in said placing member and rotates around the center of rotation of said placing member, a fluid injected into said race to be capable of moving, and a cover member which is coupled to an opening of said race for sealing the inner space of said race.    
     
     
         47 . A disk player as claimed in  claim 24 , wherein said turntable includes a placing member, which has a coupling hole coupled to said spindle motor and a placing surface on which a disk is placed, and a coupling protrusion which is formed to project from said placing member and the center hole of said disk is fittingly coupled thereto, and 
 wherein said self-compensating dynamic balancer includes at least two circular races which are formed in said placing member to be concentric and adjacent to each other and rotates around the center of rotation of said placing member, a fluid injected into each of said races to be capable of moving, and a cover member which is coupled to an opening of each race for sealing an inner space of the races.    
     
     
         48 . A disk player as claimed in  claim 1 , wherein said self-compensating dynamic balancer is formed to incorporate said clamper.  
     
     
         49 . A disk player as claimed in  claim 48 , wherein said clamper includes a clamper main body mounted to said deck base to be capable of rotating by a rotational force of said spindle motor during operation thereof, a pressing unit installed at said clamper main body to press a disk in place on said turntable, and 
 wherein said self-compensating dynamic balancer includes a circular race which is formed in said clamper main body and rotates around the center of rotation of said clamper main body, a plurality of rigid bodies which are installed in said race to be capable of moving, and a cover member which is coupled to an opening of said race to cover said race.    
     
     
         50 . A disk player as claimed in  claim 49 , further comprising a fluid which is injected into said race to be capable of moving.  
     
     
         51 . A disk player as claimed in  claim 49 , wherein a bottom surface of said clamper main body contacts said disk, and said pressing unit comprises a yoke member which is coupled to an inside lower portion of said clamper main body for pressing said disk by a magnetic attractive force with said turntable.  
     
     
         52 . A disk player as claimed in  claim 49 , wherein said pressing unit includes a pressing plate installed at a bottom surface of said clamper main body to be capable of moving up or down for pressing against said disk, and an elastic member interposed between said clamper main body and said pressing plate such that said pressing plate can elastically press against said disk.  
     
     
         53 . A disk player as claimed in  claim 49 , wherein said rigid body is formed into a shape selected from the group consisting of a spherical body which can roll inside said race, a cylindrical body which can roll while an outer circumferential surface thereof contacting an inner surface of an outer circular wall of said race, a truncated conic body which can roll while an outer circumferential surface thereof contacting a bottom surface of said race, and a fan-shaped block which can slide while being in contact with one of the bottom surface and the outer circular wall of said race.  
     
     
         54 . A disk player as claimed in  claim 49 , wherein each of said rigid bodies is formed of a non-magnetic material in order to avoid being influenced by a magnetic force.  
     
     
         55 . A disk player as claimed in  claim 54 , wherein each of said rigid bodies is formed of a substance selected from the group consisting of tungsten carbide (WC), beryllium steel (CuBe), Hastelloy C-276, silicon nitride (Si 3 N 4 ), zirconia (ZrO 2 ), brass, aluminum, austenite-series steel YHD50, a non-magnetic metal such as SUS300, SUS304 and SUS316, ceramic and a synthetic resin.  
     
     
         56 . A disk player as claimed in  claim 49 , wherein each of said rigid bodies is formed of a non-oxidizing substance which does not corrode.  
     
     
         57 . A disk player as claimed in  claim 56 , wherein each of said rigid bodies is formed of a substance selected from the group consisting of SUS300, ceramic and a synthetic resin.  
     
     
         58 . A disk player as claimed in  claim 49 , wherein a surface of each of said rigid bodies is anti-oxidation coated.  
     
     
         59 . A disk player as claimed in  claim 58 , wherein said anti-oxidation coating is formed of a material selected from the group consisting of zinc and nickel-chromium plated over a base material of carbon steel or chromium steel.  
     
     
         60 . A disk player as claimed in  claim 49 , wherein the cross-section formed by said clamper main body and said cover member in which said rigid bodies are located has a shape selected from the group consisting of a rectangular shape, an oval shape having a longer axis in a latitudinal direction with respect to the rotational shaft, and an inwardly bulging polygonal shape in which a portion of each side contacting said rigid bodies bulges inward.  
     
     
         61 . A disk player as claimed in  claim 49 , wherein said clamper main body and said cover member are formed of a non-magnetic material in order to avoid being influenced by a magnetic force.  
     
     
         62 . A disk player as claimed in  claim 61 , wherein said clamper main body and said cover member are formed of a substance selected from the group consisting of tungsten carbide (WC), beryllium steel (CuBe), Hastelloy C-276, silicon nitride (Si 3 N 4 ), zirconia (ZrO 2 ), brass, aluminum, austenite-series steel YHD50, a non-magnetic metal such as SUS300, SUS304 and SUS316, ceramic and a synthetic resin.  
     
     
         63 . A disk player as claimed in  claim 49 , wherein said clamper main body and said cover member are formed of a non-oxidizing substance which does not corrode.  
     
     
         64 . A disk player as claimed in  claim 63 , wherein said clamper main body and said cover member are formed of a substance selected from the group consisting of SUS300, ceramic and a synthetic resin.  
     
     
         65 . A disk player as claimed in  claim 49 , wherein surfaces of said clamper main body and said cover member are anti-oxidation coated.  
     
     
         66 . A disk player as claimed in  claim 65 , wherein said anti-oxidation coating is formed of a material selected from the group consisting of zinc and nickel-chromium plated over a base material of carbon steel or chromium steel.  
     
     
         67 . A disk player as claimed in  claim 48 , wherein said clamper includes a clamper main body which is mounted to said deck base to be capable of being moved by a rotational force of said spindle motor during operation thereof and a pressing unit installed at said clamper main body for pressing against the disk placed on said turntable, and 
 wherein said self-compensating dynamic balancer includes at least two circular races which are formed in said clamper main body to be concentric and adjacent to each other and rotates around the center of rotation of said main body, a plurality of rigid bodies installed inside said respective races to be capable of moving, and a cover member which is coupled to an opening of each of said races to cover said races.    
     
     
         68 . A disk player as claimed in  claim 67 , wherein weights of said rigid bodies located inside each of said races differ form each other.  
     
     
         69 . A disk player as claimed in  claim 67 , wherein a fluid is injected into at least one of said races.  
     
     
         70 . A disk player as claimed in  claim 67 , wherein a bottom surface of said clamper main body contacts said disk, and said pressing unit comprises a yoke member which is coupled to the inside lower portion of said clamper main body for pressing against said disk by a magnetic attractive force with said turntable.  
     
     
         71 . A disk player as claimed in  claim 67 , wherein said pressing unit includes a pressing plate installed at the bottom surface of said clamper main body to be capable of moving up or down for pressing said disk, and an elastic member interposed between said clamper main body and said pressing plate such that said pressing plate can elastically press against said disk.  
     
     
         72 . A disk player as claimed in  claim 48 , wherein said clamper includes a clamper main body which is mounted to said deck base to be capable of being moved by a rotational force of said spindle motor during operation thereof and a pressing against unit installed at said clamper main body for pressing the disk placed on said turntable, and 
 wherein said self-compensating dynamic balancer includes a circular race which is formed in said clamper main body and rotates around the center of rotation of said clamper main body, a fluid injected into said race to be capable of moving, and a cover member which is coupled to an opening of said race for sealing an inner space of said race.    
     
     
         73 . A disk player as claimed in  claim 48 , wherein said clamper includes a clamper main body which is installed on said deck base to be capable of being moved by a rotational force of said spindle motor during operation thereof and a pressing unit installed at said clamper main body for pressing the disk placed on said turntable, and 
 wherein said self-compensating dynamic balancer includes at least two circular races which are formed in said clamper main body to be concentric and adjacent to each other and rotates around the center of rotation of said clamper main body, a fluid injected into each of said races to be capable of moving, and a cover member which is coupled to an opening of said races for sealing an inner space of each of said races.    
     
     
         74 . A disk player as claimed in  claim 1 , wherein said self-compensating dynamic balancer is formed to incorporate said spindle motor.  
     
     
         75 . A disk player as claimed in  claim 74 , wherein said spindle motor comprises: 
 a motor base which is coupled to said deck plate;    a stator fixedly installed at said motor base and having a through hole through which said rotational shaft is rotatably installed, a yoke and a coil wound around said yoke; and    a rotor having a case which is fixed to an end of said rotational shaft and encloses said stator, and a magnet which is fixed inside said case to face said yoke, whereby said rotational shaft can be rotated by an electromagnetic force between said stator and said rotor, and    wherein said self-compensating dynamic balancer comprises a circular race which is formed integrally with said case and rotates around the center of rotation of said rotational shaft, a plurality of rigid bodies which are installed in said race to be capable of moving, and a cover member which is coupled to an opening of said race to cover said race.    
     
     
         76 . A disk player as claimed in  claim 75 , further comprising a fluid injected into said race to be capable of moving.  
     
     
         77 . A disk player as claimed in  claim 75 , wherein each of said rigid bodies is formed into a shape selected from the group consisting of a spherical body which can roll inside said race, a cylindrical body which can roll with an outer circumferential surface thereof contacting an inner surface of an outer circular wall of said race, a truncated conic body which can roll with an outer circumferential surface thereof contacting the bottom surface of said race, and a fan-shaped block which can slide being in contact with the bottom surface or the outer circular wall of said race.  
     
     
         78 . A disk player as claimed in  claim 75 , wherein each of said rigid bodies is formed of a non-magnetic material in order to avoid being influenced by a magnetic force.  
     
     
         79 . A disk player as claimed in  claim 78 , wherein each of said rigid bodies is formed of a substance selected from the group consisting of tungsten carbide (WC), beryllium steel (CuBe), Hastelloy C-276, silicon nitride (Si 3 N 4 ), zirconia (ZrO 2 ), brass, aluminum, austenite-series steel YHD50, a non-magnetic metal such as SUS300, SUS304 and SUS316, ceramic and a synthetic resin.  
     
     
         80 . A disk player as claimed in  claim 75 , wherein each of said rigid bodies is formed of a non-oxidizing substance which does not corrode.  
     
     
         81 . A disk player as claimed in  claim 80 , wherein each of said rigid bodies is formed of a substance selected from the group consisting of SUS300, ceramic and a synthetic resin.  
     
     
         82 . A disk player as claimed in  claim 75 , wherein the outer circumferential surface of each of said rigid bodies is anti-oxidation coated.  
     
     
         83 . A disk player as claimed in  claim 82 , wherein said anti-oxidation coating is formed of a material selected from the group consisting of zinc and nickel-chromium plated over a base material of carbon steel or chromium steel.  
     
     
         84 . A disk player as claimed in  claim 75 , wherein a cross-section formed by said case and said cover member in which said rigid bodies are located has a shape selected from the group consisting of a rectangular shape, an oval shape having a longer axis in the latitudinal direction with respect to the rotational shaft, and an inwardly bulging polygonal shape in which a portion of each side contacting said rigid body bulges inward.  
     
     
         85 . A disk player as claimed in  claim 75 , wherein said case and said cover member are formed of a non-magnetic material in order to avoid being influenced by a magnetic force.  
     
     
         86 . A disk player as claimed in  claim 85 , wherein said case and said cover member are formed of a substance selected from the group consisting of tungsten carbide (WC), beryllium steel (CuBe), Hastelloy C-276, silicon nitride (Si 3 N 4 ), zirconia (ZrO 2 ), brass, aluminum, austenite-series steel YHD50, a non-magnetic metal such as SUS300, SUS304 and SUS316, ceramic and a synthetic resin.  
     
     
         87 . A disk player as claimed in  claim 75 , wherein said case and said cover member are formed of a non-oxidizing substance which does not corrode.  
     
     
         88 . A disk player as claimed in  claim 87 , wherein said case and said cover member are formed of a substance selected from the group consisting of SUS300, ceramic and a synthetic resin.  
     
     
         89 . A disk player as claimed in  claim 75 , wherein surfaces of said case and said cover member are anti-oxidation coated.  
     
     
         90 . A disk player as claimed in  claim 89 , wherein said anti-oxidation coating is formed of a material selected from the group consisting of zinc and nickel-chromium plated over a base material of carbon steel or chromium steel.  
     
     
         91 . A disk player as claimed in  claim 74 , wherein said spindle motor comprises: 
 a motor base which is coupled to said deck plate;    a stator fixedly installed at said motor base and having a through hole through which said rotational shaft is rotatably installed, a yoke and a coil wound around said yoke; and    a rotor having a case which is fixed to an end of said rotational shaft and encloses said stator, and a magnet which is fixed inside said case to face said yoke, whereby said rotational shaft can be rotated by an electromagnetic force between said stator and said rotor, and    wherein said self-compensating dynamic balancer comprises at least two circular races which are formed integrally with said case to be concentric and adjacent to each other and rotates around the center of rotation of said rotational shaft, a plurality of rigid bodies which are installed in said respective races to be capable of moving, and a cover member which is coupled to an opening of said races to cover said races.    
     
     
         92 . A disk player as claimed in  claim 91 , wherein weights of said rigid bodies located inside each of said races differ form each other.  
     
     
         93 . A disk player as claimed in  claim 91 , wherein a fluid is injected into at least one of said races.  
     
     
         94 . A turntable incorporating a self-compensating dynamic balancer adopted in a disk player comprising: 
 a placing member having a coupling hole which is coupled to a rotational shaft of a motor and a surface on which a disk is placed, said placing member being rotated by rotation of said motor;    a coupling protrusion which is formed on said placing member to project therefrom and into which a center hole of a disk fits;    at least one circular race which is formed in said placing member and rotates around the rotation center of said placing member;    a mobile unit which is placed inside said race to be capable of moving;    a cover member which covers an opening of said race.    
     
     
         95 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 94 , wherein said mobile unit comprises a rigid body which can roll inside said race during rotation of said placing member.  
     
     
         96 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 95 , wherein, when there is more than one race, weights of rigid bodies located in each of said races differ from each other.  
     
     
         97 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 95 , wherein a fluid which can move in said race during rotation of said placing member is further included as said mobile unit.  
     
     
         98 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 94 , wherein said coupling protrusion includes an installation groove which is formed inside the coupling protrusion and a magnet which is inserted in said installation groove.  
     
     
         99 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 95 , wherein said rigid body is formed of a non-magnetic material in order to avoid being influenced by a magnetic force.  
     
     
         100 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 99 , wherein said rigid body is formed of a substance selected from the group consisting of tungsten carbide (WC), beryllium steel (CuBe), Hastelloy C-276, silicon nitride (Si 3 N 4 ), zirconia (ZrO 2 ), brass, aluminum, austenite-series steel YHD50, a non-magnetic metal such as SUS300, SUS304 and SUS316, ceramic and a synthetic resin.  
     
     
         101 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 95 , wherein said rigid body is formed of a non-oxidizing substance which does not corrode.  
     
     
         102 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 101 , wherein said rigid body is formed of a substance selected from the group consisting of SUS300, ceramic and a synthetic resin.  
     
     
         103 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 95 , wherein an outer circumferential surface of said rigid body is anti-oxidation coated.  
     
     
         104 . A turntable incorporating a self-compensating dynamic balancer disk player as claimed in  claim 103 , wherein said anti-oxidation coating is formed of a material selected from the group consisting of zinc and nickel-chromium plated over a base material of carbon steel or chromium steel.  
     
     
         105 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 95 , wherein said rigid body is formed into a shape selected from the group consisting of a spherical body, a cylindrical body, a truncated conic body, and a fan-shaped block.  
     
     
         106 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 94 , wherein said mobile unit comprises a fluid which can slide in said race during rotation of said placing member.  
     
     
         107 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 94 , wherein said placing member and said cover member are formed of a non-magnetic material in order to avoid being influenced by a magnetic force.  
     
     
         108 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 107 , wherein said placing member and said cover member are formed of a substance selected from the group consisting of tungsten carbide (WC), beryllium steel (CuBe), Hastelloy C-276, silicon nitride (Si 3 N 4 ), zirconia (ZrO 2 ), brass, aluminum, austenite-series steel YHD50, a non-magnetic metal such as SUS300, SUS304 and SUS316, ceramic and a synthetic resin.  
     
     
         109 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 94 , wherein said placing member and said cover member are formed of a non-oxidizing substance which does not corrode.  
     
     
         110 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 109 , wherein said placing member and said cover member are formed of a substance selected from the group consisting of SUS300, ceramic and a synthetic resin.  
     
     
         111 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 94 , wherein a surface of said placing member and said cover member facing said rigid body is anti-oxidation coated.  
     
     
         112 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 111 , wherein said anti-oxidation coating is formed of a material selected from the group consisting of zinc and nickel-chromium plated over a base material of carbon steel or chromium steel.  
     
     
         113 . A turntable incorporating a self-compensating dynamic balancer as claimed in  claim 94 , wherein a cross-section formed by said race and said cover member in which said mobile unit is located has a shape selected from the group consisting of a rectangular shape, an oval shape having a longer axis in a latitudinal direction with respect to the rotational shaft, and an inwardly bulging polygonal shape in which a portion of each side contacting said rigid body bulges inward.  
     
     
         114 . A clamper incorporating a self-compensating dynamic balancer adopted in a disk player, comprising: 
 a clamper main body;    a pressing unit which is installed at said clamper main body for pressing a disk placed on a turntable;    at least one circular race which is formed in said clamper main body and rotates around the center of rotation of said clamper main body;    a mobile unit placed inside said race to be capable of moving; and    a cover member which covers an opening of said race.    
     
     
         115 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 114 , wherein said mobile unit comprises a rigid body which can roll inside said race during rotation of said placing member.  
     
     
         116 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 115 , wherein, when there is more than one race, weights of rigid bodies located in each of said races differ from each other.  
     
     
         117 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 115 , wherein a fluid which can move in said race during rotation of said placing member is further included as said mobile unit.  
     
     
         118 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 114 , wherein a bottom surface of said clamper main body contacts said disk, and said pressing unit comprises a yoke member which is coupled to a lower portion inside said clamper main body in order to press said disk by a magnetic force with said turntable.  
     
     
         119 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 114 , wherein said pressing unit includes a pressing plate installed at a bottom surface of said clamper main body to be capable of moving up and down for pressing said disk, and an elastic member which is interposed between said clamper main body and said pressing plate such that said pressing plate can elastically press against said disk.  
     
     
         120 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 115 , wherein said rigid body is formed of a non-magnetic material in order to avoid being influenced by a magnetic force.  
     
     
         121 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 120 , wherein said rigid body is formed of a substance selected from the group consisting of tungsten carbide (WC), beryllium steel (CuBe), Hastelloy C-276, silicon nitride (Si 3 N 4 ), zirconia (ZrO 2 ), brass, aluminum, austenite-series steel YHD50, a non-magnetic metal such as SUS300, SUS304 and SUS316, ceramic and a synthetic resin.  
     
     
         122 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 115 , wherein said rigid body is formed of a non-oxidizing substance which does not corrode.  
     
     
         123 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 122 , wherein said rigid body is formed of a substance selected from the group consisting of SUS300, ceramic and a synthetic resin.  
     
     
         124 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 115 , wherein an outer circumferential surface of said rigid body is anti-oxidation coated.  
     
     
         125 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 124 , wherein said anti-oxidation coating is formed of a material selected from the group consisting of zinc and nickel-chromium plated over a base material of carbon steel or chromium steel.  
     
     
         126 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 115 , wherein said rigid body is shaped as one among a ball type, a cylindrical body, a truncated conic body, and a fan-shaped block.  
     
     
         127 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 114 , wherein said mobile unit comprises a fluid which can slide in said race during rotation of said clamper main body.  
     
     
         128 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 114 , wherein said clamper main body and said cover member are formed of a non-magnetic material in order to avoid being influenced by a magnetic force.  
     
     
         129 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 128 , wherein said clamper main body and said cover member are formed of a substance selected from the group consisting of tungsten carbide (WC), beryllium steel (CuBe), Hastelloy C-276, silicon nitride (Si 3 N 4 ), zirconia (ZrO 2 ), brass, aluminum, austenite-series steel YHD50, a non-magnetic metal such as SUS300, SUS304 and SUS316, ceramic and a synthetic resin.  
     
     
         130 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 114 , wherein said clamper main body and said cover member are formed of a non-oxidizing substance which does not corrode.  
     
     
         131 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 130 , wherein said clamper main body and said cover member are formed of a substance selected from the group consisting of SUS300, ceramic and a synthetic resin.  
     
     
         132 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 114 , wherein surfaces of said clamper main body and said cover member facing said rigid body are anti-oxidation coated.  
     
     
         133 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 132 , wherein said anti-oxidation coating is formed of a material selected from the group consisting of zinc and nickel-chromium plated over a base material of carbon steel or chromium steel.  
     
     
         134 . A clamper incorporating a self-compensating dynamic balancer as claimed in  claim 114 , wherein a cross-section formed by said race and said cover member in which said mobile unit is located has a shape selected from the group consisting of a rectangular shape, an oval shape having a longer axis in a latitudinal direction with respect to the center of rotation, and an inwardly bulging polygonal shape in which a portion of each side bulges inward.  
     
     
         135 . A spindle motor incorporating a self-compensating dynamic balancer adopted in disk player, comprising: 
 a rotational shaft;    a motor base having a through hole in which said rotational shaft is rotatably inserted;    a stator fixedly installed at said motor base and having a yoke and a coil wound around said yoke;    a rotor having a case which is fixed to an end of said rotational shaft and encloses said stator, and a magnet which is fixed inside said case to face said yoke;    at least one circular race which is integrally formed with said case and rotates around the center of rotational of said rotational shaft;    a mobile unit located inside said race to be capable of moving; and    a cover member which is coupled to an opening of said race for sealing an inner space of said race.    
     
     
         136 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 135 , wherein said mobile unit is a rigid body which can roll in said race during rotation of said case.  
     
     
         137 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 136 , wherein, when there is more than one race, weights of said rigid bodies located in each of said races differ from each other.  
     
     
         138 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 136 , wherein a fluid which can flow in said race during rotation of said case is further included as said mobile unit.  
     
     
         139 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 136 , wherein said rigid body is formed of a non-magnetic material in order to avoid being influenced by a magnetic force.  
     
     
         140 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 139 , wherein said rigid body is formed of a substance selected from the group consisting of tungsten carbide (WC), beryllium steel (CuBe), Hastelloy C-276, silicon nitride (Si 3 N 4 ), zirconia (ZrO 2 ), brass, aluminum, austenite-series steel YHD50, a non-magnetic metal such as SUS300, SUS304 and SUS316, ceramic and a synthetic resin.  
     
     
         141 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 136 , wherein said rigid body is formed of a non-oxidizing substance which does not corrode.  
     
     
         142 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 141 , wherein said rigid body is formed of a substance selected from the group consisting of SUS300, ceramic and a synthetic resin.  
     
     
         143 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 136 , wherein an outer circumferential surface of said rigid body is anti-oxidation coated.  
     
     
         144 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 143 , wherein said anti-oxidation coating is formed of a material selected from the group consisting of zinc and nickel-chromium plated over a base material of carbon steel or chromium steel.  
     
     
         145 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 136 , wherein said rigid body is formed in a shape selected from the group consisting of a ball type, a cylindrical body, a truncated conic body, and a fan-shaped block.  
     
     
         146 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 135 , wherein said mobile unit comprises a fluid which can flow in said race during rotation of said spindle motor main body.  
     
     
         147 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 135 , wherein said case and said cover member are formed of a non-magnetic material in order to avoid being influenced by a magnetic force.  
     
     
         148 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 147 , wherein said case and said cover member are formed of a substance selected from the group consisting of tungsten carbide (WC), beryllium steel (CuBe), Hastelloy C-276, silicon nitride (Si 3 N 4 ), zirconia (ZrO 2 ), brass, aluminum, austenite-series steel YHD50, a non-magnetic metal such as SUS300, SUS304 and SUS316, ceramic and a synthetic resin.  
     
     
         149 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 135 , wherein said case and said cover member are formed of a non-oxidizing substance which does not corrode.  
     
     
         150 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 149 , wherein said case and said cover member are formed of a substance selected from the group consisting of SUS300, ceramic and a synthetic resin.  
     
     
         151 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 135 , wherein surfaces of said case and said cover member facing said rigid body are anti-oxidation coated.  
     
     
         152 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 151 , wherein said anti-oxidation coating is formed of a material selected from the group consisting of zinc and nickel-chromium plated over a base material of carbon steel or chromium steel.  
     
     
         153 . A spindle motor incorporating a self-compensating dynamic balancer as claimed in  claim 135 , wherein a cross-section formed by said race and said cover member in which said mobile unit is located has a shape selected from the group consisting of a rectangular shape, an oval shape having a longer axis in a latitudinal direction with respect to the rotational shaft, and an inwardly bulging polygonal shape in which a portion of each side bulges inward.