JP2011091969A - Motor, disk drive, method for manufacturing rotor yoke, and method for manufacturing motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique suppressing the generation of a burr at the end of a rotor yoke, and firmly clamping a shaft and the rotor yoke without using an adhesive. <P>SOLUTION: A motor 113 is equipped with: stationary parts 102; and a rotary part 103 supported to the stationary parts 2 in a state rotatable around a center shaft 109 extending up and down. The stationary parts 102 has stators 123, and the rotary part and also has: a shaft 131 arranged along the center shaft;, the rotor yoke 132 clamped to the shaft 131 by a press-in and including an approximately cylindrical clamper; and a rotor magnet 133 fixed to the rotor yoke 132 and opposed in the radial direction to the stators 123. A recess 135a is formed on the inner peripheral surface of the clamper. When the shaft 131 is pressed into the clamper for the rotor yoke 132, an excessive thickness generated by squeezing the inner peripheral surface of the clamper is housed in the recess 135a, thus suppressing the generation of the burr. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a motor, a disk drive device, a rotor yoke manufacturing method, and a motor manufacturing method.

A disk drive device such as an optical disk drive is equipped with a brushless motor for rotating the disk. As an example of such a brushless motor, US Pat. No. 6,534,889 describes a motor in which a rotating shaft and a rotating body are fixed. In addition, US Pat. No. 6,600,366 describes a brushless motor having a substantially cylindrical rotor frame and a shaft having one end fixed to the rotation center of the rotor frame.
US Pat. No. 6,534,889 US Pat. No. 6,700,256

  In US Pat. No. 6,534,889, a rotary body and a rotary shaft are press-fitted and fixed, and then bonded and fixed with an adhesive. In US Pat. No. 6,600,366, an adhesive is previously applied to the inner diameter of the rotor frame, and then the shaft is press-fitted into the rotor frame.

  Thus, in US Pat. No. 6,534,889 and US Pat. No. 6,600,366, a step of applying an adhesive is provided before or after the press-fitting step. For this reason, in these fixing methods, the cost concerning adhesive itself and the manufacturing cost required for the process of apply | coating an adhesive generate | occur | produce. Further, if the adhesive adheres to other parts in the apparatus, the mobility and function of the part may be adversely affected. There is also a problem that stable fixing strength cannot be obtained unless the amount of adhesive applied is precisely controlled.

  On the other hand, when the shaft and the rotor yoke are fastened, if the shaft and the rotor yoke are to be fastened by press-fitting without using an adhesive, the press-fitting allowance needs to be increased. However, if the press-fitting allowance is increased, burrs (unnecessary protrusions) are likely to occur at the end of the rotor yoke. When the burrs are generated, the burrs may be dropped and a circuit on the substrate may be short-circuited. Further, if a process for removing such burrs is provided separately, the manufacturing cost correspondingly increases.

  An object of the present invention is to provide a technique capable of suppressing the occurrence of burrs at the end of a rotor yoke and firmly fastening the shaft and the rotor yoke without using an adhesive.

  1st invention of this application is provided with the stationary part and the rotating part supported through the bearing part by the said stationary part in the state which can rotate centering on the center axis | shaft extended up and down, The said stationary part is magnetic flux The rotating portion includes a shaft disposed along the central axis, a rotor yoke having a substantially cylindrical fastening portion fastened by press-fitting the shaft, and the rotor yoke. A rotor magnet that is fixed and is opposed to the stator in the radial direction, the fastening portion is disposed above the bearing portion, and the shaft has a portion that projects vertically from the fastening portion. The motor has a recess formed in the inner peripheral surface of the fastening portion.

  According to a second invention of the present application, in a method for manufacturing a rotor yoke having a fastening portion for being fastened to a motor shaft by press-fitting, a) a step of forming a substantially annular recess on one surface of the plate material; After the step a), a method of manufacturing a rotor yoke comprising: burring a region including the concave portion and forming the substantially cylindrical fastening portion having the concave portion on an inner peripheral surface thereof.

  A third invention of the present application is a method of manufacturing a motor having a shaft and a rotor yoke fastened to the shaft, i) having a substantially cylindrical fastening portion, and forming a recess on the inner peripheral surface of the fastening portion. A step of preparing the prepared rotor yoke, and ii) after the step i), the step of press-fitting the shaft into the fastening portion of the rotor yoke so that the shaft protrudes vertically from the fastening portion. It is a manufacturing method of the motor provided.

  According to the first and third inventions of the present application, when the shaft is press-fitted into the fastening portion of the rotor yoke, the occurrence of burrs at the axial end portion of the fastening portion is suppressed. Further, this makes it possible to firmly tighten the shaft and the rotor yoke by using a large press-fit allowance without using an adhesive.

  According to the second invention of the present application, it is possible to easily and inexpensively manufacture a rotor yoke that can suppress generation of burrs when fastened to a shaft.

FIG. 1 is a longitudinal sectional view of a motor. FIG. 2 is a longitudinal sectional view of the disk drive device. FIG. 3 is a longitudinal sectional view of the brushless motor. FIG. 4 is an enlarged longitudinal sectional view of the fastening portion and the vicinity thereof. FIG. 5 is a flowchart showing the manufacturing procedure of the rotor yoke. FIG. 6 is a diagram illustrating a state in which the concave portion is formed in the plate material. FIG. 7 is a diagram showing a state where a burring prepared hole is formed in a plate material. FIG. 8 is a diagram showing how the fastening portion is formed. FIG. 9 is a flowchart showing a procedure when the shaft is press-fitted into the rotor yoke. FIG. 10 is a diagram illustrating a state in which the shaft is press-fitted into the fastening portion. FIG. 11 is an enlarged vertical cross-sectional view of a fastening portion and its vicinity according to a modification. FIG. 12 is a longitudinal sectional view of a brushless motor according to a modification.

  Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In the following, the shape and positional relationship of each part will be described with the direction along the central axis of the motor as the vertical direction and the rotating part side as the upper part with respect to the stationary part. However, this is defined only in the vertical direction for convenience of explanation, and does not limit the installation posture when the motor and the disk drive device according to the present invention are mounted on an actual device.

<1. Circuit Board Unit According to One Embodiment>
FIG. 1 is a longitudinal sectional view of a motor 113 according to an embodiment of the present invention. As shown in FIG. 1, the motor 113 includes a stationary part 102 and a rotating part 103. The rotating part 103 is supported by the stationary part 102 via a bearing part (not shown) so as to be rotatable about a central axis 109 extending vertically.

  The stationary part 102 has a stator 123 that generates magnetic flux. On the other hand, the rotating unit 103 includes a shaft 131, a rotor yoke 132, and a rotor magnet 133. The shaft 131 is disposed along the central axis 109. The rotor yoke 132 has a substantially cylindrical fastening portion 135 fastened by press-fitting the shaft 131. The fastening portion 135 is disposed above the bearing portion. The rotor magnet 133 is fixed to the rotor yoke 132 and faces the stator 123 in the radial direction (a direction perpendicular to the central axis; the same applies hereinafter). The shaft 131 has a portion that protrudes upward and downward from the fastening portion 135. A concave portion 135 a is formed on the inner peripheral surface of the fastening portion 135.

  When manufacturing the rotor yoke 132, first, a substantially annular recess is formed on one surface of the plate. And the substantially cylindrical fastening part 135 which has the recessed part 135a in the internal peripheral surface is formed by carrying out the burring process of the area | region containing the recessed part of a board | plate material.

  Further, when the shaft 131 and the rotor yoke 132 are fastened in the manufacturing process of the motor 113, first, the rotor yoke 132 having the substantially cylindrical fastening portion 135 and the recess 135a formed on the inner peripheral surface of the fastening portion 135 is provided. prepare. Then, the shaft 131 is press-fitted into the fastening portion 135 of the rotor yoke 132 so that the shaft 131 protrudes above and below the fastening portion 135.

  In this embodiment, since the recessed part 135a is provided in the fastening part 135 of the rotor yoke 132, generation | occurrence | production of a burr | flash is suppressed when the shaft 131 is press-fit. Accordingly, it is possible to firmly tighten the shaft 131 and the rotor yoke 132 by increasing the press-fitting allowance without using an adhesive.

<2. More specific embodiment>
<2-1. Configuration of disk drive>
Subsequently, a more specific embodiment of the present invention will be described.

  FIG. 2 is a longitudinal sectional view of the disk drive device 1. The disk drive device 1 is a device that reads information from the disk 90 and writes information to the disk 90 while rotating the optical disk 90 (hereinafter simply referred to as “disk 90”) about the central axis 9. As shown in FIG. 2, the disk drive device 1 includes a housing 11, a tray 12, a brushless motor 13, a clamper 14, and an access unit 15.

  The housing 11 is a housing that houses the tray 12, the brushless motor 13, the clamper 14, and the access unit 15. The tray 12 is a mechanism for transporting the disk 90 between the outside of the housing 11 and the brushless motor 13. The brushless motor 13 is fixed to a chassis 16 provided inside the housing 11. The disk 90 transferred from the tray 12 to the brushless motor 13 is held between the rotating portion 3 of the brushless motor 13 and the clamper 14 and is rotated about the central axis 9 by the brushless motor 13.

  The access unit 15 has a head 15a having an optical pickup function. The access unit 15 moves the head 15 a along the recording surface of the disk 90 rotated by the brushless motor 13 to read information from the disk 90 and write information to the disk 90. Note that the head 15 a of the access unit 15 may perform only one of reading and writing of information with respect to the recording surface of the disk 90.

<2-2. Configuration of brushless motor>
Next, the configuration of the brushless motor 13 will be described.

  FIG. 3 is a longitudinal sectional view of the brushless motor 13. As shown in FIG. 3, the brushless motor 13 includes a stationary part 2 and a rotating part 3. The stationary part 2 is fixed to the chassis 16 of the disk drive device 1. The rotating part 3 is supported so as to be rotatable with respect to the stationary part 2.

  The stationary part 2 includes a base member 21, a stationary bearing unit 22, and a stator unit 23. The stationary bearing unit 22 is fixed to the base member 21. The stationary bearing unit 22 is a mechanism that supports the shaft 31 in a rotatable state. The stator unit 23 is fixed to the stationary bearing unit 22. The stator unit 23 includes a stator core 24 having a plurality of tooth portions 24a, and a coil 25 wound around each tooth portion 24a.

  A circuit board 26 is provided on the upper surface of the base member 21. An electronic circuit for supplying a drive current to the coil 25 is mounted on the circuit board 26.

  The rotating unit 3 includes a shaft 31, a rotor yoke 32, a rotor magnet 33, and a disk holding unit 34. The shaft 31 is a substantially cylindrical member that extends in the vertical direction along the central axis 9. The rotor yoke 32 is a member that is fixed to the shaft 31 and rotates together with the shaft 31. The rotor magnet 33 is fixed to the rotor yoke 32. The rotor magnet 33 has an annular shape, and the inner peripheral surface thereof is a magnetic pole surface facing the end surface of the tooth portion 24 a of the stator core 24.

  The rotor yoke 32 includes a fastening portion 35, a flat plate portion 36, and an outer cylindrical portion 37. The fastening portion 35 is a substantially cylindrical portion fastened to the shaft 31 by press fitting. The fastening portion 35 is disposed above the stationary bearing unit 22. The flat plate portion 36 is a portion that extends radially outward from the upper end portion of the fastening portion 35. The outer cylindrical portion 37 is a cylindrical portion that extends downward from the outer edge portion of the flat plate portion 36 and holds the rotor magnet 33 inside thereof.

  FIG. 4 is an enlarged longitudinal sectional view of the fastening portion 35 of the rotor yoke 32 and the vicinity thereof. In FIG. 4, illustration of members other than the shaft 31 and the rotor yoke 32 is omitted. As shown in FIG. 4, the shaft 31 is inserted inside the fastening portion 35 and protrudes above and below the fastening portion 35. An annular recess 35 a is formed on the inner peripheral surface of the fastening portion 35. The concave portion 35a is a groove for accommodating extra space that is thought to be generated by squeezing the inner peripheral surface of the fastening portion 35 in the step of press-fitting the shaft 31 into the rotor yoke 32. Generation of burrs at the end of the fastening portion 35 after press-fitting is suppressed by the recess 35a. Details of the process of press-fitting the shaft 31 into the rotor yoke 32 will be described later.

  Returning to FIG. The disk holding part 34 is a mechanism for holding a disk-shaped disk 90 having a hole in the center. The disk holding unit 34 includes a turntable 38 and a cone 39. The turntable 38 is fixed to the shaft 31 above the rotor yoke 32. An annular mounting member 38 a is fixed to the upper surface of the turntable 38. The upper surface of the mounting member 38a is a mounting surface on which the disk 90 is mounted.

  The cone 39 is an alignment member that supports the inner periphery of the disk 90 and aligns the center of the disk 90 with the central axis 9. The cone 39 is attached to the shaft 31 so as to be slidable in the axial direction above the fastening portion 35. The cone 39 has an inclined surface 39a whose distance from the central axis 9 expands downward. The inclined surface 39 a is a support surface that supports the inner peripheral portion of the disk 90. Further, the cone 39 is biased upward by a coil spring 40 inserted between the cone 39 and the turntable 38.

  In such a brushless motor 13, when a drive current is applied to the coil 25 of the stationary portion 2, magnetic flux is generated in the plurality of teeth portions 24 a of the stator core 24. And the torque of the circumferential direction generate | occur | produces by the effect | action of the magnetic flux between the teeth part 24a and the rotor magnet 33, and the rotation part 3 rotates centering on the central axis 9 with respect to the stationary part 2. FIG. The disk 90 held by the disk holding part 34 of the rotating part 3 rotates around the central axis 9 together with the rotating part 3.

<2-3. Manufacturing method of rotor yoke>
Then, the manufacturing method of the rotor yoke 32 of this embodiment is demonstrated. FIG. 5 is a flowchart showing a manufacturing procedure of the rotor yoke 32.

  When manufacturing the rotor yoke 32, first, a circular plate 30 serving as a prototype of the rotor yoke 32 is prepared (step S11). For example, a metal plate such as a galvanized steel plate (SECC) suitable for press forming is prepared as the plate material 30. Next, the outer cylindrical portion 37 is formed on the prepared plate member 30 (step S12). For example, the outer cylindrical portion 37 extending downward from the outer edge portion of the plate material 30 is formed by performing press processing (drawing) a plurality of times on the plate material 30.

  Subsequently, a substantially annular recess 30a centering on the central portion of the plate 30 is formed on the upper surface of the plate 30 (step S13). Here, as shown in FIG. 6, a mold 41 having a convex portion 41 a corresponding to the concave portion 30 a is pressed against the upper surface of the plate member 30. Thereby, a recess 30 a is formed on the upper surface of the plate member 30. In the present embodiment, the convex portion 41a of the mold 41 has a triangular shape in a cross-sectional view. For this reason, a substantially V-shaped recess 30 a is formed on the upper surface of the plate member 30 in a sectional view.

  Thereafter, the plate member 30 is subjected to burring to form a substantially cylindrical fastening portion. In the burring process, first, a burring prepared hole 30b is formed in the center of the plate member 30 (step S14). For example, as shown in FIG. 7, the lower hole 30 b is formed by vertically passing a small-diameter punch head 42 through the plate 30. And in the area | region containing the lower hole 30b and the recessed part 30a, the burring punch 43 is struck down from the upper direction of the board | plate material 30 like FIG. Thereby, the part 30c around the lower hole 30b rises, and the cylindrical fastening part 35 protruding downward is formed (step S15).

  In step S <b> 15, as the portion 30 c around the lower hole 30 b rises, the recess 30 a formed on the upper surface of the plate member 30 moves to the inner peripheral surface of the fastening portion 35. Thereby, an annular recess 35 a extending in the circumferential direction is formed on the inner peripheral surface of the fastening portion 35.

  Thus, in this embodiment, the fastening part 35 of the rotor yoke 32 and the recessed part 35a of the inner peripheral surface of the fastening part 35 are formed by press molding. For this reason, the fastening part 35 and the recessed part 35a can be formed easily and cheaply. However, the rotor yoke provided in the motor of the present invention may be manufactured by other manufacturing methods such as cutting and casting.

<2-4. Press fit between shaft and rotor yoke>
Next, a procedure when the shaft 31 is press-fitted into the rotor yoke 32 in the manufacturing process of the brushless motor 13 will be described. FIG. 9 is a flowchart showing a procedure when the shaft 31 is press-fitted into the rotor yoke 32.

  When the shaft 31 is press-fitted into the rotor yoke 32, first, the shaft 31 and the rotor yoke 32 are prepared (step S21). The rotor yoke 32 has a substantially cylindrical fastening portion 35, and an annular recess 35 a is formed on the inner peripheral surface of the fastening portion 35. Next, as shown in FIG. 10, the shaft 31 is press-fitted from below the fastening portion 35 of the rotor yoke 32 into the inside of the fastening portion 35 (step S22). The shaft 31 is press-fitted until its upper end protrudes above the fastening portion 35.

  In step S <b> 22, the inner peripheral surface of the fastening portion 35 is squeezed by press-fitting the shaft 31. As a result, there is a case where an excess thickness 35 b is generated on the inner peripheral surface of the fastening portion 35. The surplus thickness 35b is obtained by scraping a part of the material constituting the rotor yoke 32 from the inner peripheral surface of the fastening portion 35 into a lump shape. However, the extra wall 35b is accommodated in the recess 35a when the upper end of the shaft 31 passes through the recess 35a. For this reason, it is suppressed that a burr | flash generate | occur | produces in the upper end part of the fastening part 35 after press injection.

  In the above description, a simplified model is shown in which the surplus 35b is generated on the inner peripheral surface of the fastening portion 35, and the surplus 35b is accommodated in the recess 35a. However, the principle of suppressing burr by the recess 35a is not always such a simple mechanism. For example, it is considered that the occurrence of the excess wall 35b itself may be suppressed by the recess 35a being contracted. In any case, it is only necessary that the generation of burrs is suppressed by the space secured as the recess 35a.

  If generation | occurrence | production of a burr | flash is suppressed, generation | occurrence | production of the various problems resulting from a burr | flash can be suppressed. For example, it can be suppressed that a burr is sandwiched between the shaft 31 and the cone 39 and the cone 39 is poorly slid. Moreover, it is possible to suppress the burrs from dropping from the fastening portion 35 and coming into contact with the circuit board 26 and short-circuiting the electronic circuit on the circuit board 26. Further, in the manufacturing process of the brushless motor 13, a process for removing burrs can be reduced. For this reason, the productivity of the brushless motor 13 is improved and the manufacturing cost is reduced.

  Moreover, in this embodiment, since the generation | occurrence | production of a burr | flash can be suppressed, the interference allowance of press-fit can be enlarged. Therefore, the shaft 31 can be firmly fastened to the rotor yoke 32 by increasing the press-fitting allowance without using an adhesive. In the present embodiment, the press-fit allowance is set to 20 μm to 30 μm.

  In particular, in the present embodiment, in a state where the fastening portion 35 and the shaft 31 are fastened, the concave portion 35a is not opened to any of the upper side and the lower side. That is, a closed space is formed between the recess 35 a and the outer peripheral surface of the shaft 31. For this reason, surplus material generated during press-fitting is confined in the recess 35 a without extending upward with the movement of the shaft 31. Thereby, generation | occurrence | production of a burr | flash is prevented appropriately.

  Moreover, the recessed part 35a of this embodiment is an annular groove extending in the circumferential direction. Therefore, even if surplus occurs at any position in the circumferential direction, the surplus is accommodated in the recess 35a. For this reason, generation | occurrence | production of a burr | flash is prevented over the perimeter of the fastening part 35. FIG.

  When the shaft 31 is inserted from the lower side of the fastening portion 35, the concave portion 35a is preferably formed at a position as high as possible in the fastening portion 35 in order to efficiently accommodate the excess thickness 35b in the concave portion 35a. . For example, as shown in FIG. 4, the recess 35 a is preferably formed above the height position H <b> 1 at the center in the axial direction of the fastening portion 35.

  However, when the fastening portion 35 is formed by burring as described above, the concave portion 30a formed around the lower hole 30b moves to the inner peripheral surface of the fastening portion 35 and becomes the concave portion 35a. For this reason, it is difficult to form the recess 35a above the height position H2 of the lower surface of the flat plate portion 36. If it is the design which provides the recessed part 35a below the height position H2 of the lower surface of the flat plate part 36, the fastening part 35 and the recessed part 35a can be easily formed by burring.

  Further, the recess 35a of the present embodiment is a substantially V-shaped groove in a cross section when cut by a plane including the central axis 9. For this reason, also in the manufacturing process of the rotor yoke 32, the substantially V-shaped recessed part 30a is formed in the upper surface of the board | plate material 30 by step S13. With such a substantially V-shaped recess 30a, the flatness of the plate 30 around the recess 30a is unlikely to decrease when the mold 41 is pressed against the plate 30. Therefore, the concave portion 30a can be easily formed using the mold 41.

  If the depth d1 in the radial direction of the recess 35a is too shallow, it becomes difficult to sufficiently accommodate the surplus material generated during press-fitting. On the other hand, if the depth d1 in the radial direction of the concave portion 35a is too deep, the fastening strength of the fastening portion 35 with respect to the shaft 31 is lowered. For this reason, the depth d1 in the radial direction of the concave portion 35a is set to an appropriate value so as to ensure sufficient fastening strength between the shaft 31 and the fastening portion 35 while ensuring a space for sufficiently accommodating the surplus. It is preferable. The depth d1 in the radial direction of the recess 35a is preferably 10% or more and 30% or less, and 15% or more and 25% or less of the radial thickness d2 of the fastening portion 35, for example, in a state after press-fitting. This is more preferable.

  Moreover, in this embodiment, parts other than the recessed part 35a among the internal peripheral surfaces of the fastening part 35 are cylindrical surfaces which do not have an intentional unevenness | corrugation. Further, the outer peripheral surface of the shaft 31 is also a cylindrical surface that does not have intentional irregularities in the portion that is fastened to the fastening portion 35. For this reason, the contact area of the shaft 31 and the fastening part 35 is ensured to the maximum extent. Thereby, the shaft 31 and the fastening part 35 are fastened more firmly.

  In the present embodiment, no adhesive is used for fastening the shaft 31 and the fastening portion 35. That is, the shaft 31 and the fastening portion 35 are fastened only by press-fitting. For this reason, the cost concerning adhesive itself and the manufacturing cost required for the process of apply | coating an adhesive agent can be reduced. Moreover, it can also prevent that an adhesive agent adheres to the other site | part of the brushless motor 13, and exerts a bad influence on the mobility and function of the said site | part. For example, it is also possible to prevent the adhesive from adhering to a portion above the fastening portion 35 of the shaft 31 and reducing the slidability of the cone 39. Further, when the shaft 31 and the fastening portion 35 are fastened, it is not necessary to precisely control the amount of adhesive applied, so that the shaft 31 and the fastening portion 35 can be fastened with a stable fastening strength.

<3. Modification>
As mentioned above, although exemplary embodiment of this invention was described, this invention is not limited to said embodiment.

  For example, as shown in FIG. 11, the fastening portion 35 may protrude upward from the inner edge portion of the flat plate portion 36 of the rotor yoke 32. In this way, the concave portion 35 a can be formed in the vicinity of the upper end portion of the fastening portion 35. For this reason, when the shaft 31 is press-fitted from below the fastening portion 35, the surplus thickness 35b generated on the inner peripheral surface of the fastening portion 35 can be efficiently accommodated in the recessed portion 35a.

  Further, the shape of the recess 35a may be a shape other than a substantially V shape in a cross-sectional view. For example, the shape of the recess 35a may be substantially U-shaped in cross-sectional view. However, as described above, when the cross-sectional view is substantially V-shaped, the concave portion 30a can be easily formed using the mold 41, and a decrease in flatness in the vicinity of the concave portion 30a can be suppressed.

  Further, the peripheral edge of the upper end of the shaft 31 may be chamfered, or an arcuate curved surface may be formed in a cross-sectional view. By so doing, it is possible to suppress the occurrence of excess wall when the shaft 31 is press-fitted into the fastening portion 35. For this reason, generation | occurrence | production of a burr | flash can further be suppressed.

  Further, the disk holding portion 34 may have a turntable 38 and a cone 39 as in the above embodiment, or may be constituted by an integral member. For example, as shown in FIG. 12, the disk holding portion 34 is an integral member including a mounting surface 34 a on which the disk 90 is mounted above the rotor yoke 32 and an alignment surface 34 b that supports the inner peripheral portion of the disk 90. It may be.

  The motor of the present invention may be a brushless motor 13 for rotating the optical disk 90 as in the above embodiment, or may be a motor for rotating another recording disk such as a magnetic disk. Good.

  The present invention can be used in a motor, a disk drive device, a method for manufacturing a rotor yoke, and a method for manufacturing a motor.

DESCRIPTION OF SYMBOLS 1 Disc drive device 2,102 Static part 3,103 Rotating part 9,109 Center shaft 11 Housing 13 Brushless motor 15 Access part 21 Base member 22 Static bearing unit 23 Stator unit 30 Plate material 31, 131 Shaft 32,132 Rotor yoke 33,133 Rotor magnet 34 Disc holding portion 35, 135 Fastening portion 35a, 135a Recess 35b Extra thickness 36 Flat plate portion 37 Outer cylindrical portion 38 Turntable 39 Cone 90 Disc 113 Motor 123 Stator

Claims (12)

A stationary part;
A rotating part supported by the stationary part via a bearing part in a state of being rotatable around a central axis extending vertically;
With
The stationary part has a stator for generating magnetic flux,
The rotating part is
A shaft disposed along the central axis;
A rotor yoke having a substantially cylindrical fastening portion fastened by press-fitting the shaft;
A rotor magnet fixed to the rotor yoke and opposed to the stator in a radial direction;
Have
The fastening portion is disposed above the bearing portion,
The shaft has a portion protruding up and down from the fastening portion,
A motor in which a concave portion is formed on an inner peripheral surface of the fastening portion. The motor according to claim 1,
A motor in which the concave portion extends in the circumferential direction. In the motor according to claim 1 or 2,
The recess is a motor that is a substantially V-shaped groove in a cross section when cut along a plane including the central axis. In the motor according to any one of claims 1 to 3,
The said recessed part is a motor arrange | positioned above the center of the axial direction of the said fastening part. In the motor according to any one of claims 1 to 4,
The rotor yoke has a flat plate portion that expands in a radial direction,
The fastening portion is a portion protruding downward by burring from the inner edge of the flat plate portion,
The concave portion is a motor positioned below the lower surface of the flat plate portion. In the motor according to any one of claims 1 to 4,
The rotor yoke has a flat plate portion that expands in a radial direction,
The said fastening part is a motor which is a part protruded upwards from the inner edge part of the said flat plate part. In the motor according to any one of claims 1 to 6,
The depth of the concave portion in the radial direction is 10% or more and 30% or less of the radial thickness of the fastening portion. The motor according to any one of claims 1 to 7,
The rotating part further includes a disk holding part for holding a disk-shaped disk having a hole in the center,
The disk holding part is
A mounting member for mounting a disk above the rotor yoke;
An alignment member that is slidably attached in the axial direction to a portion of the shaft that is located above the fastening portion, and supports the inner peripheral portion of the disk;
Having a motor. The motor according to any one of claims 1 to 7,
The rotating part further includes a disk holding part for holding a disk-shaped disk having a hole in the center,
The disk holding part is
A mounting surface on which a disk is mounted above the rotor yoke;
An alignment surface that supports the inner periphery of the disk;
A motor that is an integrated member. A motor according to claim 8 or claim 9,
An access unit that performs at least one of reading and writing of information with respect to the disk held in the disk holding unit of the motor;
A housing for housing the motor and the access unit;
A disk drive device comprising: In a method of manufacturing a rotor yoke having a fastening portion for being fastened to a motor shaft by press fitting,
a) forming a substantially annular recess on one surface of the plate;
b) after the step a), burring the region including the recess, and forming the substantially cylindrical fastening portion having the recess on the inner peripheral surface thereof;
A method for manufacturing a rotor yoke. In a method of manufacturing a motor having a shaft and a rotor yoke fastened to the shaft,
i) preparing a rotor yoke having a substantially cylindrical fastening portion and having a recess formed on the inner peripheral surface of the fastening portion;
ii) after the step i), press-fitting the shaft into the fastening portion of the rotor yoke, and projecting the shaft vertically from the fastening portion;
A method for manufacturing a motor comprising:

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