JP4810920B2 - Spindle motor and recording disk device equipped with this spindle motor - Google Patents

Description

  The present invention relates to an inner rotor type spindle motor that is reduced in size and thickness and a recording disk device equipped with the spindle motor.

  In recent years, miniaturization and portability of information recording / reproducing apparatuses have been advanced. In particular, a hard disk drive (hereinafter referred to as HDD) is mounted on a mobile phone and contributes to an increase in the recording capacity of the mobile phone. In order to mount an HDD on a mobile phone, it is essential to make the HDD smaller. Along with this, miniaturization of the spindle motor mounted on the HDD is essential. In order to meet these demands, the base that is the housing of the HDD is manufactured by press working to reduce the size of the base, and as a result, the spindle motor is reduced in size (such as this conventional As an example of a spindle motor using the press processing of the base, see Patent Document 1).

JP 2002-084707 A

  However, when mounting an HDD on a mobile phone, high impact resistance is essential so that the HDD can withstand failure even when the mobile phone is dropped. For this purpose, it is necessary to increase the thickness of the base. However, the conventional base places importance on the shape and dimension of the base, and the thickness of the base is reduced in order to achieve the dimensional accuracy.

  In the base pressing, a plurality of protrusions are provided on the base side at equal intervals in the circumferential direction in order to determine the axial position of the stator. However, if the base plate is thick, it is difficult to form the protrusions on the base, and the variation in the dimensions of the upper surfaces of the protrusions increases. In addition, since the protrusions are provided on the core back side of the stator, the radial position between the stator side surface abutting cylindrical portion of the base and the protrusions is close, and bending due to the pressing process is continued, so that the pressing process is difficult. For this reason, the accuracy of the protrusion is low. As a result, the stator is inclined in the circumferential direction, which may cause vibration and noise of the motor.

  Accordingly, the present invention simultaneously solves the conflicting demands of downsizing and improvement in impact resistance as described above, and the object is to reduce the size of the spindle motor and increase the thickness of the base. It is an object of the present invention to provide a spindle motor that can improve impact resistance.

According to the first aspect of the present invention, the rotating member that rotates about the rotating shaft, the armature that is a fixing member that radially surrounds the rotating member, and the rotating member and the armature are accommodated. a spindle motor comprising a base, a having a circular recess, the armature has a plurality of thin plates having a core back portion of the substantially annular, the tooth portion formed on the inner circumferential opposite release morphism shape, the And a winding wound around the teeth portion of the stator core, and the thin plate has a protruding portion in the axial direction at a part of the core back. And a projecting portion for positioning the armature in the axial direction is provided on the surface facing the base of the stator core so as to contact the base, and the projecting portion is a radius of the winding of the armature. Outside the direction and Located radially inward from the outer peripheral edge of the back, characterized that you.

  According to the first aspect of the present invention, by providing a protrusion for positioning the armature in the axial direction on the stator core side of the armature, it is not provided on the base side. Since the distance can be shortened, the spindle motor can be miniaturized. Further, since no protrusion is provided on the base side, the base can be thickened. As a result, it is possible to provide a spindle motor capable of improving impact resistance and vibration resistance.

According to claim 2 of the present invention relates to claim 1, wherein the protrusion is characterized by being arranged in the circumferential direction at equal intervals.

According to claim 2 of the present invention, by arranging a plurality of protrusions at equal intervals in the circumferential direction, the contact portion between the base and the stator is not annular. Therefore, it is possible to position the stator in the axial direction independent of the surface accuracy of the base.

According to claim 3 of the present invention relates to any one of claims 1 to 2, wherein the protruding portion is characterized in that the axial height of the thickness hereinafter of the thin plate.

According to claim 3 of the present invention, by providing the protrusions in the core back of the stator, it is possible to form the height of the thickness hereinafter the protrusions thin plate. Therefore, the spindle motor can be thinned. In addition, if a protrusion is provided on the base, it becomes difficult to form the protrusion if the distance between the protrusion and the circular recess becomes narrow. The protrusion can be formed at a free position. As a result, the spindle motor can be reduced in size.

According to a fourth aspect of the present invention, a recording disk drive device includes a recording disk having a magnetic recording layer, and a magnetic for recording information on the magnetic recording layer and reproducing information recorded on the magnetic recording layer. A brushless motor according to any one of claims 1 to 3 , further comprising: a head; a moving unit for moving the magnetic head with respect to the recording disk; and a rotary drive for rotating the magnetic disk. It is characterized by.

According to the fourth aspect of the present invention, a highly reliable recording disk drive device can be provided by mounting a spindle motor excellent in shock resistance and vibration resistance on the recording disk drive device. In particular, it is most suitable for a recording disk drive device mounted on a portable device that requires impact resistance and vibration resistance.

  According to the present invention, it is possible to provide a spindle motor that can improve the impact resistance by reducing the size of the spindle motor and increasing the plate thickness of the base, and that has good positioning accuracy in the axial direction of the stator.

<Recording disk drive>
FIG. 1 is a schematic axial sectional view showing an embodiment of a recording disk drive device such as an HDD according to the present invention.

  Referring to FIG. 1, a recording disk drive apparatus 1 includes a housing 2 having a substantially rectangular shape, and the housing 2 forms a clean space with extremely little dust and dirt, and the like. An annular recess 2a is formed, and a spindle motor 4 on which a disk-like hard disk 3 for recording information is mounted is disposed. The housing 2 and the base 10 described later may be integrally formed.

  A head moving mechanism 5 for reading / writing information from / to the hard disk 3 is disposed inside the housing 2. The head moving mechanism 5 includes a magnetic head 5 a for reading / writing information on the hard disk 3, and the magnetic head 5 a The supporting arm 5b and the magnetic head 5a and the arm 5b are configured by an actuator unit 5c that moves the arm 5b to a required position on the hard disk 3.

  By applying the spindle motor of the present invention as the spindle motor 4 of the recording disk drive device 1 as described above, the recording disk drive device 1 can be reduced in size and thickness while ensuring a sufficient function, and also reliable. In addition, a recording disk drive having high impact resistance can be provided.

<Overall structure of spindle motor>
FIG. 2 is a schematic axial sectional view showing an embodiment of a spindle motor according to the present invention.

  With reference to FIG. 2, it is the substantially rectangular housing 2 of FIG. 1, and the base 10 processed by plastic processing, such as press processing, is formed with a circular recess 11 in part. An upper protruding portion 12 that is further opened is formed at the center of the circular recess 11.

  A sleeve holding member 20 formed in a substantially cylindrical shape with both ends opened is fixed to the upper protruding portion 12 of the base 10 by adhesion or the like. An annular step portion 21 extending outward in the radial direction is formed on the outer peripheral surface of the sleeve holding member 20. The axial position of the sleeve holding member 20 is determined by abutting the lower surface of the annular step portion 21 and the upper surface of the upper protruding portion 12 of the base 10. Further, on the outer peripheral surface on the upper side from the annular stepped portion 21, a tapered portion 22 is formed that extends upward and radially outward. A sealing disk 30 is fixed to the lower end of the sleeve holding member 20 by welding or the like so as to cover the opening.

  A cylindrical sleeve 40 having openings at both ends is fixed to the inner peripheral surface of the sleeve holding member 20 by adhesion or the like.

  The rotor hub 50 is disposed so as to surround the sleeve holding member 20 and the sleeve 40. The rotor hub 50 includes a shaft body portion 51 that rotates coaxially with a rotation shaft, a cylindrical portion 52, and a connecting portion 53 that connects these.

  A shaft body portion 51 of a substantially cylindrical rotor hub 50 is inserted into the inner peripheral surface of the sleeve 40 in a radial direction with a minute gap interposed therebetween. The cylindrical portion 52 is formed with an extending portion 52a extending radially outward. The rotor magnet 60 is fixed by adhesion or the like so as to contact the outer peripheral surface of the cylindrical portion 52 and the lower surface of the extending portion 52a. Further, an extension 52b that covers the upper surface of the rotor magnet 60 is formed below the extension 52a. A mounting surface 52c for mounting a magnetic disk (not shown in FIG. 2) is formed on the upper surface of the extending portion 52a.

  Further, the lower surface of the connecting portion 53 and the upper surface of the sleeve holding member 20 are disposed in the axial direction via a minute gap. And the lower surface of the connection part 53 and the upper surface of the sleeve 40 are arrange | positioned through a gap | interval.

  Further, a through hole is formed in the shaft body portion 51, and a cap 70 is fixed to the lower end portion of the through hole. The cap 70 is formed with a substantially cylindrical axial projecting portion 71 and a disc portion 72 at the center. And it hold | maintains by fixing the axial direction protrusion part 71 and the through-hole of the shaft body part 51. FIG. The disk portion 72 and the lower surface of the sleeve 40 form a minute gap in the axial direction. The disk portions 72 are arranged so as to provide a gap between the upper surface of the sealing disk 30 and the inner peripheral surface of the sleeve holding member 20.

  An upper radial dynamic pressure groove 41 and a lower radial dynamic pressure groove 42 are formed on the inner peripheral surface of the sleeve 40, and the rotor hub 50 is rotatably supported in the radial direction. An upper thrust dynamic pressure groove 22 and a lower thrust dynamic pressure groove 43 are formed on the upper surface of the sleeve holding member 20 and the lower surface of the sleeve 40, respectively, and support the rotor hub 50 rotatably in the axial direction. Then, fluid dynamic pressure is generated in each dynamic pressure groove during rotation by filling each dynamic pressure groove with the lubricating fluid up to the middle of the inner peripheral surface of the cylindrical portion 52 of the rotor hub 50 without being substantially interrupted. Thus, the rotor hub 50 is rotationally supported.

  A stator 80 is fixed to the inner peripheral surface of the circular recess 11 of the base 10 by adhesion or the like. The stator 80 formed by laminating the thin plates includes a stator core including a substantially annular core back portion 81 and teeth portions 82 that are disposed at equal intervals in the circumferential direction and radially formed radially inward, and the teeth portion 82. The winding 83 is wound around the periphery of the wire. The inner peripheral surface of the tooth portion 82 and the outer peripheral surface of the rotor magnet 60 are opposed to each other via a minute gap in the radial direction.

  On the upper surface of the stator 80, a flexible circuit board 90 such as a flexible circuit board that supplies power from the outside is fixedly disposed by bonding or the like. The circuit board 90 is electrically connected to the end of the winding 83 by soldering. Further, an annular shield plate 100 is fixed to the base 10 so as to cover the circuit board 90.

  When power is supplied to the stator 80 from the external power source through the circuit board 90, a magnetic field is generated in the stator 80, and a rotational driving force is obtained by the interaction between this magnetic field and the rotor magnet 60.

<Main part>
A relationship between the base 10 and the stator 80, which is a main part according to the present invention, will be described with reference to FIG. FIG. 3 is an enlarged view of the main part of FIG.

  A protrusion 84 is formed on the lower side in the axial direction of the core back portion 81 of the stator core in the stator 80. The lower surface of the projection 84 and the upper surface of the base 10 facing the lower surface are in contact with each other, so that the axial position of the stator 80 is determined. As a result, it is not necessary to form a protrusion on the base 10 side, so that the plate thickness can be increased within a range where thickness reduction and vibration reduction are achieved.

  The thickness of the laminated thin plates constituting the stator 80 of the present embodiment is about 0.2 mm, and the axially lower protrusion 84 formed on the thin plate is about 0.1 mm. Compared to the stator 80, the base 10 needs to have a thickness of about 0.4 mm in consideration of impact resistance and vibration resistance. Therefore, the thickness of the base 10 is about twice that of the thin plate of the stator 80. In general, in plastic working such as press working, the larger the plate thickness, the more difficult it is to form protrusions, and the accuracy decreases.

  In addition, the radial distance from the inner peripheral edge to the outer peripheral edge of the core back portion 81 is about 5 mm. Therefore, the outer peripheral edge of the core back portion 81 is located on the radially outer side, which is about 1 mm away from the radially outer side of the protrusion 84. An inner peripheral surface of the circular recess 11 to which is fixed in contact is formed. For this reason, the distance from the protrusion 84 to the circular recess 11 is short, and the base 10 is extended between each other by about 1 mm to form the protrusion 84 and the circular recess 11. It is difficult to form the protrusion 84. Furthermore, there is a possibility that a problem that the height accuracy of the protrusion 84 is lowered due to the influence of the bending of the circular recess 11 is caused. As a result, the heights of the protrusions 84 vary. For this reason, the stator 80 that performs axial positioning by the protrusion 84 may vary in height in the circumferential direction, and may generate vibration.

  Further, if the distance from the protrusion 84 to the circular recess 11 is increased, it is formed inside the inner peripheral edge of the core back portion 81 of the stator 80, and the original function of positioning the stator 80 in the axial direction is lost. . Therefore, it is difficult to form the positioning protrusions 84 of the stator 80 when the radial distance from the inner peripheral edge to the outer peripheral edge of the core back portion 81 is 5 mm or less. Therefore, it has been difficult to reduce the size of the spindle motor.

However, by providing the projections 84 on the lower side of the core back 81 of the stator 80 of the present embodiment, it is possible to accurately form the height of the collision raised portion 84. Therefore, there is no variation in the circumferential height of the stator 80, and the occurrence of vibration can be suppressed, and the reduction of noise caused by this vibration can be realized. This further increases the plate thickness of the base 10, so that the rigidity of the spindle motor can be improved. As a result, the impact resistance of the spindle motor can be improved. This is particularly suitable for HDDs used in portable devices. Further, since no bending or recess is formed on the outer side in the radial direction of the core back 81, it is not necessary to consider other influences on the formation of the protrusion 84. Therefore, it is possible to cope with further downsizing of the spindle motor.

< Reference example of protrusions>
A reference example of the protrusion 84 provided on the stator 80 will be described with reference to FIGS. The protrusions 84 are denoted as 84a, 84b, and 84c in the order of each reference example . FIG. 5 shows a top view of the stator core.

Referring to a) of FIG. 4, the protrusion 84a is formed on the core back portion 81 of the stator 80 at the same time as the stator shape is formed in the state of one thin plate, and is formed by laminating the thin plates. The This ensures that, it is possible to suppress the processing cost of the scan stator 80.

  4B, the protrusion 84b may be formed by cutting and raising the core back portion 81 of the stator 80.

  Referring to FIG. 5, a protruding portion 85 is provided radially inward between adjacent tooth portions 82 of the core back portion 81 of the stator 80, and at least one thin plate at the lowest layer of the protruding portion 85 is disposed on the lower side in the axial direction. The protrusion 84c is formed by deforming. As a result, even if the spindle motor is further reduced in size, the radial gap between the projection 84c and the circular recess 11 of the base 10 can be increased, so that the bending of the circular recess 11 formed by bending is effective. It will not be affected by the deterioration of surface accuracy. Therefore, the axial positioning of the stator 80 can be performed satisfactorily. As a result, it is possible to provide a spindle motor that realizes low vibration and low noise in a small spindle motor.

  Although the details of the embodiment of the present invention have been described above, the present invention is not limited to this embodiment, and various modifications are possible.

  For example, the stator 80 of the present invention is formed by stacking four thin plates as shown in FIGS. 1 to 4, but the present invention is not limited to this, and the number of stacks may be any number.

1 is a schematic cross-sectional view showing an embodiment of a recording disk drive device according to the present invention. It is the schematic cross section which showed one form of the spindle motor concerning this invention. It is a principal part enlarged view of FIG. It is the figure which showed the other reference example of FIG. It is the figure which showed the other reference example of FIG.

DESCRIPTION OF SYMBOLS 10 Base 11 Circular recessed part 20 Sleeve holding member 30 Sealing disk 40 Sleeve 50 Rotor hub 60 Rotor magnet 70 Cap 80 Stator 81 Core back part 82 Teeth part 83 Winding 84, 84a, 84b, 84c Projection part 85 Projection part 90 Circuit board 100 Shield plate

Claims (4)

A rotating member that rotates about a rotation axis;
An armature that is a fixed member that radially surrounds the rotating member;
A base having a circular concave portion for accommodating the said armature and said rotary member,
A spindle motor comprising:
The armature is
A core back portion of the substantially annular, a stator core formed by stacking a plurality of thin plates having a tooth portion, the on an inside circumferential opposite release morphism shape,
A winding wound around the teeth portion of the stator core, and
The thin plate has a protruding portion in the axial direction in a part of the core back,
Protruding portions for positioning the armature in the axial direction are provided on the base facing surface of the stator core so as to contact the base ,
The protrusion includes a spindle motor that radially outwardly of the winding of the armature, and located radially inward of the outer peripheral edge of the core back, characterized that you. The spindle motor according to claim 1 wherein the protrusions, characterized in that arranged in the circumferential direction at equal intervals.   The spindle motor according to claim 1, wherein the protrusion has an axial height equal to or less than a thickness of the thin plate.   A recording disk having a magnetic recording layer;
  A magnetic head for recording information on the magnetic recording layer and reproducing the information recorded on the magnetic recording layer;
  Moving means for moving the magnetic head relative to the recording disk;
  4. A recording disk drive apparatus comprising: the spindle motor according to claim 1 for rotating the magnetic disk.

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