JP2008181622A - Spindle motor and information recorder using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin type spindle motor provided with a chucking device which can suppress effectively vibration caused in a recording disk. <P>SOLUTION: The spindle motor is provided with a disk placing member 60A supporting a lower plane of the recording disk on an upper plane of a rotor holder 22, and is set so that at least either of area at which the lower plane of the recording disk is abutted on the disk placing member 60A and area a which the disk placing member 60 is abutted on the upper plane of the rotor holder 22 is uneven in the peripheral direction. Thereby, the recording disk is held axis-asymmetric for a rotation axis, so as to hardly resonate on a vibration mode of axis-symmetric. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a spindle motor for rotating a recording disk in a predetermined direction and an information recording apparatus incorporating the spindle motor.

  In recent years, there is an increasing demand for miniaturization and thinning of spindle motors for driving recording disks such as CDs and DVDs. For this reason, not only a motor mechanism for generating a driving force but also a chucking mechanism for holding a disk has been devised to reduce the size and thickness.

  The chucking mechanism that holds the disk can be broadly divided into a clamp system that holds the disk using a clamper provided separately from the motor, and a ball chuck system that has a chucking mechanism that holds the disk in the motor itself. And can be classified into two types. Among these, the clamp method has a drawback that the apparatus is large because the clamper is provided separately from the motor, and the thickness of the entire apparatus increases. For this reason, the ball chuck method has gradually become mainstream for small and thin models.

  The ball chuck type chucking mechanism will be described in more detail.

  As an example of a ball chuck type chucking mechanism (see, for example, Patent Document 1), three elastic springs arranged in a substantially cylindrical case at equal intervals in the circumferential direction and three elastic springs engaged with the elastic springs. One having two chuck portions incorporated therein is disclosed. The chuck portion protrudes to a position having a slightly larger outer diameter than the center hole of the recording disk. When the center hole of the recording disk is inserted into the case, the chuck portion is first moved to the periphery of the center hole of the recording disk by an elastic spring. When the recording disk is moved inward in the radial direction and the recording disk comes below the chuck part, the chuck part moves outward in the radial direction by the restoring force of the elastic spring to hold the recording disk. .

JP 2000-207721 A

  However, the ball chuck method has the following drawbacks. That is, in the ball chuck system, the recording disk is held by the biasing force of the elastic spring. Further, due to the structure of the ball chuck system, the portion where the recording disk can be held by the holding claws is limited to the vicinity of the central opening of the recording disk. As a result, the holding force with respect to the recording disk is not sufficient, and the recording disk is more likely to vibrate compared to a clamp system that holds and holds substantially the same radial position of the recording disk from the upper and lower sides in the axial direction. Yes.

  Here, the vibration problem will be described in detail. A recording disk that is rotationally driven by a spindle motor is generally a thin disk. When the recording disk vibrates due to an external force while the disk is held, the vibration modes of a plurality of typical thin disks with different natural frequencies overlap. It becomes a vibration shape. Examples of these vibration modes are shown in FIG. FIG. 12A shows an example in which a vibration node extends in the radial direction through the central axis of rotation and two nodes are orthogonal to each other. In this figure, the region 200 indicated by “+” and the region 202 indicated by “−” are always shaken in the opposite directions, and when the “+” region 200 becomes a peak of vibration, the region “−”. When “202” becomes a trough of vibration and “+” region 200 becomes a trough of vibration, “−” region 202 becomes a peak of vibration. FIG. 12B shows an example in which the vibration nodes are concentric. In this case as well, the “+” region 204 and the “−” region 206 are reversed. Swing to.

  The above vibration modes are examples, and there are many vibration modes in addition to these vibration modes. However, as described above, when the holding condition of the recording disk is substantially uniform in the circumferential direction, any vibration mode is the rotation center axis. The vibration node in each vibration mode is composed of a combination of a straight line that passes through the axis of the rotation center axis and equally divides the recording disk and a concentric circle centered on this axis.

  When the excitation frequency generated by the rotation of the motor coincides with the natural frequency in the specific vibration mode, the recording disk resonates, and the recording disk vibrates extremely in the vibration mode. In general, the motor is symmetric with respect to the rotation center as a rotating system, and the excitation force generated in the motor is almost symmetric with respect to the rotation center. Therefore, the eigenvalues of the vibration mode shape that is symmetric with respect to the center of rotation as described above have a characteristic that it is particularly likely to resonate and vibrate greatly, and a recording disk held under uniform conditions in the circumferential direction vibrates greatly. easy.

  When the vibration of the recording disk becomes large in this way, it becomes difficult to accurately read and write information by the pickup, causing a reading error and writing error, and causing vibration and noise.

  Various techniques have been conventionally used for suppressing vibration of the recording disk.

  Patent Document 2 describes a method of damping vibration by additionally installing a dynamic vibration absorber in a clamp mechanism, but the mechanism is complicated and it is difficult to reduce the thickness. Further, Patent Document 3 describes in detail a method of reducing the response amplitude of the recording disk by making the circumferential clamping state non-uniform, but the relationship between the definition and degree of non-uniformity and the effect is not clear. It is clear. Patent Document 3 has a structure using a clamper, and it is difficult to reduce the thickness.

JP-A-6-150532 JP-A-11-328794

  In the case of the ball chuck type, a measure to increase the urging force of the elastic spring in order to suppress the vibration of the recording disk can be considered, but in this case, there are the following problems. First, when the urging force of the elastic spring is increased, the force (so-called mounting force) necessary for mounting the recording disk on the spindle motor increases, and the characteristics of the chucking device deteriorate. In addition, due to the structure in which a plurality of holding claws are provided in the circumferential direction, the recording disk cannot be held over the entire circumference of the central opening of the recording disk. Occurs. If this distortion becomes severe, there is a risk that the information cannot be read well by the pickup mechanism due to the distortion of the recording disk, and that the recording disk is cracked. Therefore, there is a limit in obtaining the disc holding force by strengthening the biasing force of the elastic spring.

  Another problem when the ball chuck method is adopted is that the disk holding force is weaker than that of the clamp method, so that the recording disk slides when rotational torque is applied to the recording disk during rotation.

  In recent years, spindle motors that drive optical disks such as CDs and DVDs have been required to be smaller, thinner, and quieter.

  From the viewpoint of miniaturization and thinning, recent models have appeared that are ultra-thin with an information recording device with an overall height of 7 mm or less. The spindle motor mounted on this ultra-thin information recording apparatus must accommodate all the drive mechanism, bearing mechanism, and disk holding mechanism within the thickness of 7 mm or less, and the thinning is approaching its limit. Therefore, it is necessary to adopt a ball chuck method. However, if the ball chuck method is adopted, vibration and noise problems are likely to occur. This spindle motor is also thinner than the conventional turntable. As a result, the rigidity of the turntable itself is reduced, and it is easier to vibrate.

  An object of the present invention is to provide a spindle motor that effectively suppresses vibration of a recording disk due to downsizing and thinning of the spindle motor without increasing the axial thickness, and has excellent noise and writing / reading accuracy. There is to do.

  The present invention is a spindle motor including a chucking device that allows a disk-shaped recording disk having a central opening to be freely attached and detached, and rotates together with the shaft about a predetermined rotation center axis and the shaft. A turntable, a disk mounting member provided on the upper surface of the turntable and supporting the lower surface of the recording disk, and disposed in a central portion on the turntable, rotating together with the turntable, and the recording disk A chucking case having a substantially conical surface into which the central opening of the recording disk is fitted, and a biasing so as to protrude radially outward from the chucking case, and engages with the central opening of the recording disk to perform the recording. A chucking device having a plurality of holding claws for holding a disc, and when the recording disc is placed At least one of the area where the lower surface of the recording disk and the disk mounting member abut and the area where the disk mounting member and the upper surface of the turntable abut is set to be nonuniform in the circumferential direction. It is characterized by that.

  According to the present invention, since the recording disk is held in an unbalanced state with respect to the rotation center axis of the spindle motor, the vibration mode of the held recording disk is axially asymmetric with respect to the rotation center axis of the recording disk. Therefore, it is difficult to receive the excitation force from the rotationally driven motor, and the vibration of the recording disk can be suppressed. Further, this effect can be realized without increasing the axial height.

  Further, at least one of the outer diameter and the inner diameter of the disk mounting member in the present invention is characterized in that the radial distance from the rotation center axis is not uniform in the circumferential direction.

  According to the present invention, it is easy to provide imbalance of the recording disk with respect to the rotation center axis of the spindle motor, and vibration generated in the recording disk is effectively attenuated.

  The disk mounting member according to the present invention includes a support portion that is in contact with the recording disk on an upper surface and is fixed to the turntable on a lower surface, and a thin portion that is thinner than the support portion. To do.

  According to the present invention, it is easy to provide imbalance of the recording disk with respect to the rotation center axis of the spindle motor, and vibration generated in the recording disk is effectively attenuated.

  In the present invention, the thin-walled portion is in contact with the recording disk on the upper surface, and the lower surface has a gap with the turntable.

  According to the present invention, imbalance of the recording disk with respect to the rotation center axis of the spindle motor can be provided without reducing the contact area between the recording disk and the disk mounting member. Therefore, it is possible to hold the recording disk with respect to the turntable so as not to slip.

  In the present invention, the thin portion is in contact with the turntable on the lower surface, and the upper surface has a gap with the recording disk.

  According to the present invention, an imbalance with respect to the rotation center axis of the recording disk can be easily provided. Further, the disk mounting member can be attached to the spindle motor relatively easily.

  In the present invention, the thin portion is formed by applying heat to the disc mounting member.

  According to the present invention, imbalance with respect to the rotation center axis of the recording disk can be easily imparted, and mass productivity can be improved.

  The turntable according to the present invention has an abutting portion with which the disc mounting member abuts on an upper surface thereof, and a non-abutting that is depressed below the corresponding contacting portion and faces the disc placing member through a gap. And the area of the non-contact portion is non-uniform in the circumferential direction.

  According to the present invention, an imbalance with respect to the rotation center axis of the recording disk can be easily provided. Moreover, the assembling property at the time of mass production is good.

  In the present invention, the disk mounting member has a substantially arc shape.

  According to the present invention, it is easy to provide imbalance of the recording disk with respect to the rotation center axis of the spindle motor.

  In the present invention, the disk mounting member has a substantially annular shape.

  According to the present invention, the assemblability during mass production is good.

  In the present invention, a plurality of the disk mounting members are provided.

  According to the present invention, the degree of freedom of the arrangement of the disk mounting member is good, and an optimal arrangement can be selected for unbalanced holding of the recording disk.

  In the present invention, the disk mounting member is provided unevenly in the circumferential direction.

  According to the present invention, it is easy to provide imbalance of the recording disk with respect to the rotation center axis of the spindle motor.

  In the present invention, at least one of the plurality of disk mounting members is different from at least one of the other disk mounting members in an area in contact with the recording disk.

  According to the present invention, it is easy to provide imbalance of the recording disk with respect to the rotation center axis of the spindle motor.

  In the present invention, the turntable has a thickness of 0.4 mm or less.

  According to the present invention, since the thickness of the turntable is thin, the spindle motor can be reduced in size and thickness. In addition, vibration and noise are easily generated by making the turntable thin. However, in the present invention, the recording disk is held unbalanced with respect to the rotation center axis, so that vibration and noise can be suppressed.

  In the present invention, the disk mounting member is molded from rubber, and a plurality of convex portions are formed on the surface thereof.

  According to the present invention, since the plurality of convex portions play a role of preventing slipping, the recording disk is less likely to slip with respect to the turntable.

  In the present invention, the disc mounting member has a thickness of 0.2 mm or less.

  According to the present invention, since the disk mounting member is thin, the spindle motor can be thinned. Further, by reducing the thickness of the disk mounting member, it is possible to avoid a decrease in flatness accuracy due to a difference in elastic deformation of the disk mounting member.

  In the present invention, the disk mounting member is a material containing a silicone resin.

  According to the present invention, the silicone resin has excellent physical properties and is suitable for thinning the disk mounting member.

  In the present invention, the information recording apparatus includes a housing and a spindle motor that is fixed inside the housing and rotates the recording disk in the information recording apparatus to which a disk-shaped recording disk having a central opening is mounted. And a spindle motor according to any one of claims 1 to 16, wherein the spindle motor is an information recording device having information access means for writing or reading information at a required position of the recording disk. It is characterized by being.

  According to the present invention, it is possible to provide a thin information recording apparatus with less vibration and noise.

  Embodiments of a spindle motor according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a first embodiment of a spindle motor according to the present invention. FIG. 2 is a configuration diagram of an information storage device to which the spindle motor is attached. FIG. 3 is a plan view showing the spindle motor of FIG. FIG. 4 is an enlarged view of a disk mounting member in the spindle motor. FIG. 5 is a plan view showing a modification of the disk mounting member in the present embodiment.

  With reference to FIG. 1, the structure of the spindle motor 1 of this invention is demonstrated. The spindle motor 1 includes a fixed portion 10 and a rotating portion 20.

  The fixed portion 10 includes a substantially cylindrical bearing bush 12. A mounting plate 14 is fixed to the lower side of the bearing bush 12 in the axial direction. A stator 16 is fixed to the outer peripheral surface of the bearing bush 12. A substantially cylindrical sleeve bearing 40 made of a sintered material is fitted and fixed to the inner peripheral surface of the bearing bush 12 inside the bearing bush 12 in the radial direction. The lower end opening of the bearing bush 12 is closed by a lid member 18.

  The rotating unit 20 includes a covered cylindrical rotor holder 22. The rotor holder 22 has an annular peripheral side wall 24 and a lid part 26 provided at an end of the peripheral side wall 24, and a shaft 28 is fixed to the center part of the lid part 26. The central axis of the shaft 28 serves as the rotation center axis, and constitutes the rotation center axis of the recording disk 50 described later. The shaft 28 is inserted into a through support hole 42 of the sleeve bearing 40 and is rotatably supported by the sleeve bearing 40, and its end surface is rotated by a thrust plate 44 provided on the inner bottom surface of the bearing bush 12, that is, the upper surface of the lid member 18. It is supported freely. Thus, the radial load acting on the shaft 28 is supported via the sleeve bearing 40, and the thrust load acting on the shaft 28 is supported via the thrust plate 44.

  A rotor magnet 30 is mounted on the inner peripheral surface of the peripheral side wall 24 of the rotor holder 22. In this embodiment, the rotor holder 22 is made of a magnetic material and plays the role of a yoke. A stator 16 is disposed to face the rotor magnet 30. The stator 16 has a stator core 32 mounted on the outer peripheral surface of the bearing bush 12 and a coil 34 wound around the stator core 32 as required. When a current is supplied to the coil 34, the rotor holder 22 is rotationally driven in a predetermined direction by the magnetic action of the stator 16 and the rotor magnet 30.

  In this embodiment, a disk mounting member 60 is affixed on the outer peripheral side of the upper surface of the lid portion 26 of the rotor holder 22, and a recording disk 50 (for example, CD-ROM, DVD, etc.) is attached to the upper surface of the disk mounting member 60. Is placed. That is, in this embodiment, the rotor holder 22 serves as a turntable. In order to increase the frictional force with respect to the recording disk 50, the disk mounting member 60 is formed of an elastic member such as rubber, and is pasted on the lid portion 26 of the rotor holder 22 with an adhesive, for example. The thickness of the lid 26 of the rotor holder 22 is 0.35 mm, and the thickness of the disk mounting member 60 is approximately 0.2 mm. The disk mounting member 60 will be described later.

  The recording disk 50 has a disk shape, and a circular center opening functioning as a positioning hole is formed at the center thereof. On the other hand, a chucking case 64 is attached to the upper end portion of the rotor holder 22, and the chucking case 64 is provided with a guide portion 65 that forms a substantially conical surface whose outer diameter gradually decreases upward. With this configuration, the central opening of the recording disk 50 is fitted with the guide portion 65. As a result, the recording disk 50 is guided by the guide portion 65 and positioned and placed on the upper side of the disk placing member 60.

  Further, the chucking case 64 constitutes a part of a chucking device 66 for holding the recording disk 50. The chucking device 66 includes a holding claw 68 that engages with the recording disk 50 mounted on the upper side of the disk mounting member 60, and the holding claw 68 is moved in the radial direction by a deformation restoring operation mechanism using an elastic spring 70. It is free. The lower surface of the holding claw 68 acts as a disk engaging surface. When the holding claw 68 is in the holding position, the engaging surface engages with the upper part on the inner peripheral side of the recording disk 50, and thus the recording disk 50 is held between the disk mounting member 60 and the holding claw 68. . On the other hand, when the recording disk 50 moves upward, the holding claws 68 are pushed upward and moved, and enter the inside of the chucking case 64 according to the inclination of the engaging surface, and the holding state by the holding claws 68 is released and loaded. The placed recording disk 50 can be removed from the chucking device 66. Such holding claws 68 are made of, for example, a synthetic resin material.

  Further, the chucking device 66 includes a centering claw 72. The aligning claw 72 is provided integrally with the chucking case 64 and is provided in a cantilever manner. The aligning claw 72 presses the central opening of the recording disk 50 with elasticity radially outward when the recording disk 50 is mounted, and aligns the information recording surface of the recording disk 50 so as to be coaxial with the rotation center axis. To do.

  As described above, in this embodiment, a so-called ball chuck system is adopted for holding the disk. Further, the rotor holder 22 also serves as a turntable. Furthermore, the thickness of the lid portion 26 of the rotor holder 22 is suppressed to 0.4 mm or less. The disk mounting member 60 is formed of a thin rubber of about 0.2 mm. With this configuration, the overall height of the spindle motor 1 is kept low, and the spindle motor 1 and the electronic device on which the spindle motor 1 is mounted are reduced in thickness.

  Next, the internal configuration of the information recording apparatus 100 on which the spindle motor 1 is mounted will be described with reference to FIG. The information recording device 100 includes a spindle motor 1 having a chucking device 66, a pickup device 80 for writing or reading information at a required position of the recording disk 50 when the motor rotates, and a housing 82 surrounding these. , Is composed of.

  In this embodiment, the disk mounting member 60A is configured as shown in FIG. 3 in order to suppress the vibration of the recording disk 50 that occurs during rotation. Referring to FIG. 3, the disk mounting member 60A is divided into a plurality of (three in this embodiment) arcuate disk mounting members 60A1, 60A2, and 60A3 which are divided and arranged in the circumferential direction. It is provided and arranged on substantially the same circumference around the rotation center axis. The intervals in the circumferential direction are uneven, and in this embodiment, the disk mounting member 60A is formed so as to be biased to the right side in the figure.

  The mounting state of the recording disk 50 on the rotor holder 22 is uneven in the circumferential direction, that is, the area of the disk mounting member 60A that is in direct contact with the lower surface of the recording disk 50 and the area of the rotor holder 22 that is in direct contact with the disk mounting member 60A (hereinafter, With respect to the area T), the portion where the disk mounting member 60A is affixed has the area T and the portion where the disk mounting member 60A is not affixed is disposed so as not to have the area T at the same radial position in the circumferential direction. Since these are unevenly arranged in the circumferential direction, the recording disk 50 is held in a state of being discontinuous in the circumferential direction and axially asymmetric with respect to the rotation center axis.

  When the recording disk 50 is held in an axially asymmetric manner with respect to such a rotation center axis, the vibration mode of the recording disk 50 also becomes axially asymmetric. Therefore, even if axially symmetric excitation is generated when the spindle motor 1 is rotated, the recording disk 50 is difficult to resonate, and vibration generated in the recording disk 50 can be effectively suppressed.

  In this embodiment, in order to prevent the recording disk 50 from sliding relative to the disk mounting member 60A during rotation, the surface of the portion of the disk mounting member 60A that supports the recording disk 50 is as shown in FIG. It is configured. The disc mounting member 60A is formed of rubber containing silicone resin. Since the silicone resin is excellent in heat resistance and dimensional accuracy, the thickness of the disk mounting member 60A can be set thin.

  Referring to FIG. 4, a hill portion 74 having a height of several tens of μm and a width of several hundreds of μm is regularly arranged on the surface of the portion of the disc mounting member 60A that supports the recording disc 50. This configuration plays the role of anti-slip. Hereinafter, in the description of FIG. 4, a portion where the hill portion 74 is not formed on the surface of the disk mounting member 60 </ b> A is referred to as a groove portion 76.

  The mechanism of non-slip is explained. As described above, the spindle motor 1 in this embodiment employs a so-called ball chuck system as the chucking device 66. When the recording disk 50 is mounted on the spindle motor 1, the recording disk 50 is pressed downward in the axial direction, and the lower surface of the recording disk 50 presses the disk mounting member 60A downward in the axial direction. The disc mounting member 60A is made of rubber, and the hill portion 74 is elastically contracted downward in the axial direction by a pressing force applied from the recording disc 50 when the recording disc 50 is mounted. Here, since the height of the hill portion 74 is very small, such as several tens of μm, the height of the hill portion 74 and the height of the groove portion 76 are substantially the same during contraction. Thereafter, when the mounting of the recording disk 50 is completed, the pressing force for pressing the recording disk 50 downward in the axial direction decreases, and the hill portion 74 tends to expand upward in the axial direction due to elasticity. As a result, the gap between the recording disk 50 and the groove 76 is in a substantially vacuum state, and the recording disk 50 is attracted to the disk mounting member 60A. Thereby, it is possible to prevent the recording disk 50 from sliding with respect to the rotating unit 20.

  Further, as described above, by setting the thickness of the disk mounting member 60A to about 0.2 mm, it is possible to prevent the recording surface of the recording disk 50 from shaking due to elastic deformation of the disk mounting member 60A.

  In the above-described embodiment, in order to clearly show that the holding state of the recording disk 50 becomes an axially asymmetric state that is non-uniform in the circumferential direction, the disk mounting member 60A has three arcs having the same shape. Although an example has been described in which the circumferentially spaced gaps are arranged on the circumference, the present invention is not limited to this. As long as holding conditions that are non-uniform in the circumferential direction and axially asymmetric are obtained, they can be set as appropriate. The same applies to the setting in the embodiment described later.

  For example, the number of arcs may be one, two or four or more as long as the recording disk 50 can be stably held, or two or more arcs may be used. Also good. Further, the disk mounting member 60A may have a shape other than an arc shape. Further, as shown in FIG. 5, the area T at the same radial position in the circumferential direction is increased or decreased by increasing or decreasing at least one of the inner diameter or the outer diameter of the disk mounting member 60B having a substantially annular shape in the circumferential direction. In this way, the recording disk 50 may be held non-uniformly in the circumferential direction and an axially asymmetric holding state may be formed.

  Further, in the above-described embodiment, the configuration of the anti-slip is the configuration in which the hill portion 74 is arranged with regularity, but is not limited thereto. For example, the groove 76 may be arranged with regularity. Moreover, the hill part 74 and the groove part 76 do not necessarily need to be arrange | positioned with regularity, and should just be the structures which exhibit the effect of anti-slip | skid.

  Further, in the above-described embodiment, the rotor holder 22 may be subjected to nitriding treatment. As a result, the rigidity of the rotor holder 22 itself increases, and the vibration of the spindle motor 1 is reduced.

  Moreover, in the above-mentioned Example, although the rotor holder 22 assumed to serve as a turntable, it is not limited to this. A turntable separate from the rotor holder may be provided. For example, a structure in which the turntable is made of resin may be used.

  FIG. 6 is a plan view showing a disk mounting member 60C of the spindle motor 1 according to the second embodiment. FIG. 7 is a cross-sectional view taken along the line AA ′ of the disk mounting member 60C shown in FIG. FIG. 8 is a view showing a rubber sheet 90 which is a base material of a first modified form of the disk mounting member 60D according to the present embodiment. FIG. 9 is a plan view showing a first modification of the disk mounting member 60D according to the present embodiment.

  The disc mounting member 60C may be configured by reducing a part of the thickness as shown in FIGS. 6 and 7, for example. In the present embodiment, a portion of the disk mounting member 60 </ b> C where the upper surface and the lower surface are in contact with both the recording disk 50 and the rotor holder 22 is defined as a support portion 62. Further, a portion of the disc mounting member 60B that is thinner than the support portion 62 is defined as a thin portion 78.

  In the present embodiment, the disc mounting member 60C is provided in an annular shape, and the support portion 62 and the thin portion 78 are provided so as to be non-uniform in the circumferential direction. Since the thin portion 78 is thinner than the support portion 62, it does not come into contact with both the lower surface of the recording disk 50 and the upper surface of the rotor holder 22 at the same time. Accordingly, the support portion 62 and the thin portion 78 have different areas T, and they are arranged non-uniformly in the circumferential direction. It is in an axially asymmetric holding state.

  In FIG. 7A, the thin portion 78A is in contact with the rotor holder 22 on its lower surface. With this configuration, the disc mounting member 60 </ b> C can be fixed to the rotor holder 22 in a stable state.

  In FIG. 7B, the thin portion 78B comes into contact with the recording disk 50 on the upper surface. With this configuration, the recording disk 50 comes into contact with the disk mounting member 60C in a wide area, and the slip stopper shown in the first embodiment can be formed in a wide area. The recording disk 50 is prevented from slipping.

FIG. 8 shows a rubber sheet 90 which is a base material of a disk mounting member 60D which is a first modification of the present embodiment.
As described above, the rubber sheet 90 is formed of rubber containing a silicone resin. The above-mentioned anti-slip is provided on the surface of the surface that supports the recording disk 50. An adhesive layer for bonding and fixing to the rotor holder 22 is provided on the surface facing the rotor holder 22.

Hereinafter, the manufacturing process of the disk mounting member 60D will be described.
First, the rubber sheet 90 is fixed on a work table with the surface on which the adhesive layer is formed facing upward. Next, the heated jig is pressed against the heating unit 92 shown in the drawing from the upper side of the rubber sheet 90. This jig may be a trowel or a roller. The adhesive layer of the heating unit 92 heated by the jig changes its property due to heat and loses adhesive force. Further, the adhesive layer of the heating unit 92 changes its properties due to heat and contracts. As a result, a thin portion 78 is formed.
Thereafter, the rubber sheet 90 is punched into the shape of the disk mounting member 60D using a die-cutting jig such as a Thomson blade. As a result, it is possible to obtain a disk mounting member 60 </ b> D having the support portion 62 and the thin portion 78 as shown in FIG. 9. The cross section of the disk mounting member 60D obtained by this manufacturing process is such that the thin portion 78 is in contact with the recording disk 50 on the upper surface as shown in FIG.

  As described above, the thickness of the disk mounting member 60 is about 0.2 mm, and it is difficult to form the thin portion 78 by cutting. In this respect, the thin-walled portion 78 can be formed relatively easily by the heating method. Further, since the thin portion 78 is formed in the state of the rubber sheet 90, the thin portion 78 can be formed at a time on the plurality of disk mounting members 60, and the mass productivity is excellent.

  In addition, after attaching the annular disk mounting member 60D to the rotor holder 22, the heated jig is pressed against the upper surface of the disk mounting member 60D to locally heat denature, thereby reducing the thickness of the portion. The thin-walled portion 78 can be formed. The cross section of the disk mounting member 60D obtained by this process is as shown in FIG.

  In FIG. 8 of the present embodiment, the heating unit 92 is formed in a band shape, but is not limited thereto. It can be formed in a desired shape by changing the shape of the jig.

  In this embodiment, the disk mounting members 60C and 60D are provided in an annular shape, but the present invention is not limited to this. It can be formed into a desired shape by changing the shape of the die-cutting jig. Here, from the viewpoint of reliability, there is a demand for stably mounting the disk mounting member 60 to the rotor holder 22. In this regard, it is preferable that the disk mounting member 60 has an annular shape. Moreover, since it can be attached by one operation | work, there also exists an effect that man-hour reduction is possible. On the other hand, from the viewpoint of mass production efficiency, there is a request to increase the number of disk mounting members 60 per rubber sheet 90. In this respect, since the number of arcs can be increased more than the circular shape, from the viewpoint of mass production efficiency, it is desirable that the disk mounting member 60 has an arc shape.

  FIG. 10 is a cross-sectional view of the third embodiment of the spindle motor 1. FIG. 11 is a plan view of the spindle motor 1 shown in FIG. 10 (the disk mounting member 60E is not shown in FIG. 11).

  Referring to FIGS. 10 and 11, the spindle motor 1 according to the present embodiment includes a contact portion 94 that is a plane provided on the upper surface of the rotor holder 22 substantially perpendicular to the rotation center axis, and is axially below the contact portion 94. A non-contact portion 96 that is depressed to the side is provided unevenly in the circumferential direction. In this embodiment, an annular disk mounting member 60E is attached to the contact portion 94, and the non-contact portion 96 is configured to face the disk mounting member 60E with a gap therebetween, so that the non-contact portion Since the area T at 96 is different from the contact portion 94, this is an example in which an unbalance is provided so as to increase or decrease in the circumferential direction. Since the disk mounting member 60E is made of rubber and has elasticity, when the non-contact portion 96 is provided over a wide range, the portion of the disk mounting member 60E that faces the non-contact portion 96 is a shaft. It is possible that the non-contact portion 96 is in contact with the lower surface of the disk mounting member 60E due to bending and deformation in the lower direction. In such a case, since the disk mounting member 60E located on the upper side in the axial direction of the non-contact portion 96 is not in contact with the recording disk 50, the contact portion 94 and the non-contact portion 96 have an area. T is different and can be unbalanced.

  In addition, the non-contact part 96 can be provided by press work, for example.

  In the present embodiment, the disk mounting member 60E has an annular shape, but the shape is not limited to this. For example, various shapes such as an arc shape can be used.

  The embodiments of the information recording apparatus 100 and the spindle motor 1 according to the present invention have been described above, but the present invention is not limited to such embodiments, and various modifications and corrections can be made without departing from the scope of the present invention. Is possible.

  For example, in the illustrated embodiment, the removable recording disk 50 typified by CD-ROM and DVD has been described as an example. However, the present invention is not limited to this, and the CD, MO, floppy disk and the like are driven to rotate. The present invention can also be similarly applied to the above-mentioned drive device or removable hard disk drive device.

It is sectional drawing which shows the 1st Example of the spindle motor according to this invention. It is a block diagram of the information storage device according to this invention. It is a top view which shows arrangement | positioning of the disk mounting member in the spindle motor of FIG. 1 in a 1st Example. It is an enlarged view which shows the surface of the disc mounting member in a 1st Example. It is a top view which shows the 1st modification of the disc mounting member in a 1st Example. It is a top view which shows the structure of the disc mounting member in a 2nd Example. It is sectional drawing which shows the structure of the disc mounting member in a 2nd Example. It is a figure which shows the rubber sheet which is a base material of the 1st modification of the disc mounting member in a 2nd Example. It is a top view which shows the 1st modification of the disc mounting member in a 2nd Example. It is sectional drawing of the spindle motor in a 3rd Example. It is a top view of the spindle motor in the 3rd example. It is explanatory drawing for demonstrating the vibration generate | occur | produced in a recording disc.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brushless motor 10 Fixed part 12 Bearing bush 14 Mounting plate 16 Stator 18 Lid member 20 Rotating part 22 Rotor holder (turn table)
24 peripheral side wall 26 lid portion 28 shaft 30 rotor magnet 32 stator core 34 coil 40 sleeve bearing 42 through support hole 44 thrust plate 50 recording disc 60, 60A, 60B, 60C, 60D, 60E disc mounting member 62 support portion 64 chucking case 65 Guide part 66 Chucking device 68 Holding claw 70 Elastic spring 72 Alignment claw 74 Hill part (convex part)
76 Groove portions 78, 78A, 78B Thin portion 80 Pickup device 82 Housing 90 Rubber sheet 92 Heating portion 94 Contact portion 96 Non-contact portion 100 Information recording device

Claims (17)

A spindle motor including a chucking device that allows a disk-shaped recording disk having a central opening to be freely attached and detached,
A shaft serving as a predetermined rotation center axis;
A turntable that rotates with the shaft about the shaft;
A disk mounting member provided on the upper surface of the turntable and supporting the lower surface of the recording disk;
A chucking case disposed at a central portion on the turntable and rotating together with the turntable and having a substantially conical surface into which a central opening of the recording disk is fitted; and a radially outward direction from the chucking case A chucking device having a plurality of holding claws that are biased so as to protrude and engage with a central opening of the recording disk to hold the recording disk,
At the time of mounting the recording disk, at least one of an area where the lower surface of the recording disk and the disk mounting member abut and an area where the disk mounting member and the upper surface of the turntable abut is circumferential. The spindle motor is characterized in that it is set to be non-uniform.   2. The spindle motor according to claim 1, wherein at least one of the outer diameter and the inner diameter of the disk mounting member has a non-uniform radial distance from the rotation center axis in the circumferential direction.   The disk mounting member includes a support portion that is in contact with the recording disk on an upper surface and is fixed to the turntable on a lower surface, and a thin portion that is thinner than the support portion. The spindle motor according to claim 2.   4. The spindle motor according to claim 3, wherein the thin portion is in contact with the recording disk on an upper surface thereof, and has a gap between the lower surface and the turntable.   4. The spindle motor according to claim 3, wherein the thin portion is in contact with the turntable on the lower surface thereof, and the upper surface has a gap between the recording disk and the recording disk.   The spindle motor according to claim 3, wherein the thin portion is formed by applying heat to the disk mounting member.   The turntable includes a contact portion with which the disk mounting member abuts on an upper surface thereof, and a non-contact portion that is depressed below the contact portion and faces the disk mounting member through a gap, 7. The spindle motor according to claim 1, wherein the area of the non-contact portion is non-uniform in the circumferential direction.   8. The spindle motor according to claim 1, wherein the disk mounting member has a substantially arc shape.   The spindle motor according to claim 2, wherein the disk mounting member has a substantially annular shape.   The spindle motor according to claim 1, wherein a plurality of the disk mounting members are provided.   The spindle motor according to claim 10, wherein the disk mounting members are provided unevenly in a circumferential direction.   The at least one of the plurality of disk mounting members is different from at least one of the other disk mounting members in an area in contact with the recording disk. Spindle motor.   The spindle motor according to claim 1, wherein the turntable has a thickness of 0.4 mm or less.   The spindle motor according to any one of claims 1 to 13, wherein the disk mounting member is molded of rubber, and a plurality of convex portions are formed on a surface thereof.   The spindle motor according to claim 1, wherein a thickness of the disk mounting member is 0.2 mm or less.   16. The spindle motor according to claim 1, wherein the disk mounting member is made of a material containing silicone resin. In an information recording apparatus to which a disc-shaped recording disk having a central opening is mounted, a casing, a spindle motor that is fixed inside the casing and rotates the recording disk, and information at a required position of the recording disk An information recording apparatus having an information access means for writing or reading data, wherein the spindle motor is the spindle motor according to any one of claims 1 to 16.

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