JP2007236146A - Spindle motor and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spindle motor that can be inexpensively manufactured, without using a special member and machining method and is capable of smoothly rotating an optical disk, and to provide a method of manufacturing the same. <P>SOLUTION: The spindle motor A has a turntable 1, an output shaft 2, a bearing member 3, a housing 4, a core 5, a rotor case 6, and a base plate 7. The bearing member 3 is press-fitted into the housing 4, while being in contact with a protruding strip 42 formed on the inner peripheral wall 411 of the housing 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a spindle motor for stably rotating the optical disk, which is used in an optical disk apparatus for recording and / or reading data by irradiating an optical disk with laser light.

  2. Description of the Related Art Optical discs that can record and / or read information by irradiating a laser beam are used as recording media for information such as video and audio. As the optical disc, a CD (Compact Disc), a DVD (Digital Versatile Disc) and the like are widely used. An optical disk apparatus using these optical disks as recording media reads information recorded in advance on the optical disk or rotates information on a recordable optical disk by rotating the optical disk and irradiating the recording surface of the optical disk with laser light. Or record.

FIG. 7 is a longitudinal sectional view of an example of a spindle motor provided in a conventional optical disc apparatus.
The spindle motor D shown in FIG. 7 includes an output shaft 92 on which a turntable 91 on which an optical disk Ds is placed is fitted, a bearing member 93 that rotatably supports the output shaft 92, and a bearing member 93 inside. A bottomed cylindrical housing 94 that is press-fitted and fixed, and a large number of driving coils 950 are attached to the outer peripheral portion at predetermined intervals in the circumferential direction, and a core 95 that is press-fitted and fixed in a through hole 951 formed in the center. The permanent magnet 960 is disposed on the inner peripheral surface so as to face the driving coil 950, and the output shaft 92 is press-fitted and fixed in the through hole 961 formed in the center of the bottom. A rotor case 96, a base plate 97 having a through hole 971 into which the housing 94 is press-fitted and fixed, and a substrate 98 for supplying power to the drive coil 950. There.

  The housing 94 is formed by deep drawing of a metal plate such as an iron plate or a steel plate, and has a bottomed cylindrical shape. A recess 941 for inserting the output shaft 92 is formed in the bottom portion 940 of the housing 94, and an annular stopper ring 99 is disposed on the bottom portion 940. After the stopper ring 99 is arranged on the bottom portion 940 of the housing 94, the stopper ring 99 is prevented from coming off by press-fitting the bearing member 93.

  A concave groove 921 is formed on the end portion of the output shaft 92 along the circumference on the circumferential curved surface. By pushing the tip of the output shaft 92 into a center hole 991 formed at the center of the stopper ring 99, the diameter of the center hole 991 is increased, and the output shaft 92 passes through the stopper ring 99. The stopper ring 99 (center hole 991) engages with the concave groove 921 of the output shaft 92 to prevent the output shaft 92 from coming out of the housing 94.

  FIG. 8 shows an enlarged cross-sectional view of a portion where the bearing member, rotor case, and base plate of the spindle motor housing shown in FIG. 7 are press-fitted. As shown in FIG. 8, a small diameter portion 943 having a small inner diameter and a large diameter portion 944 having a large inner diameter are formed on the inner peripheral wall 942 of the housing 94 so as to be continuous. The small diameter portion 943 is formed on the bottom portion 940 side, and the large diameter portion 944 is formed on the opening side. Similarly, the outer peripheral wall 945 is formed with a small diameter portion 946 at a position corresponding to the small diameter portion 943 of the inner peripheral wall 942 and a large diameter portion 947 at a position corresponding to the large diameter portion 944.

  The bearing member 93 is formed with a bearing hole 930 that extends in the axial direction at the center and supports the output shaft 92 in a rotatable manner. A small diameter portion 931 having a small outer diameter and a large large diameter portion 932 are formed on the outer peripheral wall of the bearing member 93 so as to be continuous. The outer diameter of the large diameter portion 932 of the bearing member 93 is slightly larger than the inner diameter of the small diameter portion 943 of the inner peripheral wall 942 of the housing 94 and smaller than the large diameter portion 944 of the inner peripheral wall 942.

  The bearing member 93 is press-fitted into the housing 94 and fixed so that the large-diameter portion 932 of the bearing member 93 and the small-diameter portion 943 of the inner peripheral wall 942 of the housing 94 are pressed against each other. By adjusting the length of the contact portion Tp between the large-diameter portion 932 of the bearing member 93 and the small-diameter portion 943 of the inner peripheral wall 942 of the housing 94, the force necessary for press-fitting the bearing member 93 and the bearing member 93 by the housing 94 are adjusted. Holding power is determined.

  The large diameter portion 946 of the outer peripheral wall 945 of the housing 94 is press-fitted into the through hole 951 of the core 95, and the small diameter portion 947 is press-fitted and fixed to the through hole 971 of the base plate 97.

The spindle motor D shown in FIG. 7 and FIG. 8 receives power from the permanent magnet 960 and rotates the rotor case 95 by supplying electric power from the substrate 98 and exciting the driving coil 950. The output shaft 92 that is press-fitted and fixed to the rotor case 95 and the turntable 91 that is press-fitted and fixed to the output shaft 92 are rotated to rotate the optical disk Ds placed on the turntable 91 (see Japanese Patent Application Laid-Open No. 11-230181, etc.) ).
JP-A-11-230181

  The bearing member 93 is press-fitted into the small-diameter portion 943 of the inner peripheral wall 942 of the housing 94, and the small-diameter portion 946 of the outer peripheral wall 945 is press-fitted into the through hole 971 of the base plate 97. That is, in the portion near the bottom portion 940 of the housing 94, the members are press-fitted in both the inner peripheral wall 942 and the outer peripheral wall 945. Usually, when the other member is press-fitted into one member, the accuracy of the shape and size of both members at the press-fitting portion is highly required.

  That is, the inner diameter of the small diameter portion 943 of the inner peripheral wall 942 of the housing 94 and the outer diameter shape and size of the large diameter portion 932 of the bearing member 93, the outer diameter of the small diameter portion 947 of the outer peripheral wall 945 of the housing 94 and the through hole of the base plate 97. The shape and size of the inner diameter of 971 must be accurately formed.

  However, the housing 94 is formed by deep drawing a metal plate, and the inner and outer diameters of the same cylindrical portion, such as the small diameter portion 943 of the inner peripheral wall 942 and the small diameter portion 947 of the outer peripheral wall 945, are deep drawn. It is difficult to mold with high accuracy.

  Therefore, the present invention is a spindle motor that rotates a turntable on which an optical disk is placed, and can be manufactured at low cost without using a special member and processing method, and can smoothly rotate the optical disk. It is an object of the present invention to provide a spindle motor that can perform the same and a manufacturing method thereof.

  In order to achieve the above object, the present invention provides an output shaft on which a turntable for mounting an optical disk is fitted, a bearing member that rotatably supports the output shaft, and the bearing member is press-fitted and fixed therein. A bottomed cylindrical housing, a plurality of driving coils attached to the outer periphery at predetermined intervals in the circumferential direction, a core in which the housing is press-fitted and fixed in a through hole formed in the center, and a bottomed cylindrical shape A rotor case that press-fixes the output shaft so that the bottom portion is located in a through hole formed in the center of the bottom portion, and the housing is press-fitted and fixed. A base plate having a through-hole, and rotating the rotor case by exciting the drive coil to drive the optical disc through the output shaft and the turntable. A plurality of ridges extending in the axial direction protruding inward on the inner peripheral wall of the housing and having an end portion pressed against the outer periphery of the bearing member at equal central angular intervals, The outer peripheral wall of the housing is formed such that a portion into which the through hole of the core is press-fitted and a portion into which the through-hole of the base plate is press-fitted have the same outer diameter.

  According to this configuration, when the bearing member is press-fitted into the housing, the outer peripheral wall of the bearing member is fitted so as to be in pressure contact with the ridge, so that the bearing member can be firmly fixed to the housing. It is. Further, the accuracy of the inner diameter of the inner peripheral wall does not have to be high at the fixed position when the housing is press-fitted and fixed in the through hole of the core and the fixed position when the housing is press-fitted and fixed into the through hole of the base plate. Can be manufactured. Moreover, the oil groove formed in the bearing can be reduced, and the manufacturing cost can be reduced accordingly.

  In this configuration, it is necessary to press-fit the bearing member into the housing by adjusting the protruding length from the inner peripheral wall of the ridge (the length from the central axis of the housing to the tip of the ridge). It is possible to adjust the force and the holding force of the bearing member of the housing.

  To achieve the above object, the present invention provides an output shaft, a bearing member that rotatably supports the output shaft, a bottomed cylindrical housing having a bottom portion into which the bearing member is press-fitted and fixed, A large number of driving coils are attached to the outer peripheral portion at predetermined intervals in the circumferential direction, the core is press-fitted and fixed in a through hole formed in the center, and is formed in a bottomed cylindrical shape and is fixed to the inner peripheral surface. A permanent magnet is disposed, and a rotor case for press-fitting and fixing the output shaft so that the bottom is on the through-hole formed at the center of the bottom, and a through-hole for press-fitting and fixing the housing at the center are provided. A spindle motor having a base plate and rotating the rotor case and the output shaft by exciting the driving coil, wherein the inner peripheral wall of the housing protrudes inward and the tip portion is A plurality of ridges press-contacted with the outer periphery of the bearing member are formed at equal central angular intervals, and the outer peripheral wall of the housing is press-fitted with a portion into which the through-hole of the core is press-fitted and the through-hole of the base plate. The portion is formed to have the same outer diameter.

  According to this configuration, when the bearing member is press-fitted into the housing, the outer peripheral wall of the bearing member is fitted so as to be in pressure contact with the ridge, so that the bearing member can be firmly fixed to the housing. It is. Further, the accuracy of the inner diameter of the inner peripheral wall does not have to be high at the fixed position when the housing is press-fitted and fixed in the through hole of the core and the fixed position when the housing is press-fitted and fixed into the through hole of the base plate. Can be manufactured.

  In this configuration, it is necessary to press-fit the bearing member into the housing by adjusting the protruding length from the inner peripheral wall of the ridge (the length from the central axis of the housing to the tip of the ridge). It is possible to adjust the force and the holding force of the bearing member of the housing.

  The said structure WHEREIN: The said protruding item | line may be arrange | positioned in the direction extended to the central axis of the said housing. Still further, the ridges may be formed in a plurality of stages in the axial direction of the housing.

  Moreover, the said structure WHEREIN: The protruding item | line adjacent to the said axial direction may be arrange | positioned by the predetermined | prescribed center angle shift | offset | difference to the circumferential direction of the said housing.

  To achieve the above object, the present invention provides an output shaft, a bearing member that rotatably supports the output shaft, a bottomed cylindrical housing having a bottom portion into which the bearing member is press-fitted and fixed, and an outer periphery A large number of driving coils are attached to the section at predetermined intervals in the circumferential direction, and the housing is press-fitted and fixed in a through hole formed in the center, and is formed in a bottomed cylindrical shape and fixed to the inner peripheral surface A base plate having a permanent magnet and a rotor case for press-fitting and fixing the output shaft so that the bottom is on the through-hole formed in the center of the bottom, and a through-hole in which the housing is press-fitted and fixed at the center A spindle motor for rotating the rotor case and the output shaft by exciting the drive coil, and forming a protrusion on the metal disk in advance, Article characterized in that it deep drawing using a pin having a groove formed in the axial direction at positions corresponding to the convex strip from the plane convex strip protrudes a metal disk which is formed.

  According to this configuration, the outer diameter of the outer peripheral wall is required to be highly accurate at the contact portion of the housing with the core and the contact portion with the base plate, but the inner diameter of the inner peripheral wall is not required to have high accuracy. Therefore, the time and labor required for manufacturing can be reduced, and the manufacturing cost can be reduced accordingly.

  In addition, it is possible to manufacture a mold necessary for accurately manufacturing the inner diameter of the inner peripheral wall and the outer diameter of the outer peripheral wall in the same cylindrical portion, and it is possible to reduce the manufacturing cost accordingly.

  The said structure WHEREIN: The said protruding item | line may be formed in the said metal disc by a half punch.

  According to the present invention, a spindle motor that rotates a turntable on which an optical disk is placed, which can be manufactured at low cost without using special members and processing methods, and that the optical disk can be smoothly rotated. And a manufacturing method thereof.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross-sectional view of an example of a spindle motor according to the present invention. A spindle motor A shown in FIG. 1 includes an output shaft 2 on which a turntable 1 on which an optical disk Ds is placed is fitted, a bearing member 3 that rotatably supports the output shaft 2, and a bearing member that is press-fitted inside. A fixed bottomed cylindrical housing 4, a core 5 in which a large number of driving coils 50 are attached to the outer periphery at predetermined intervals in the circumferential direction, and the housing 4 is press-fitted and fixed in a through hole 51 formed in the center; The permanent magnet 60 is formed on the inner peripheral surface so as to face the driving coil 50, and the output shaft 2 is press-fitted and fixed in the through hole 61 formed in the center of the bottom. It has a rotor case 6, a base plate 7 having a through hole 71 into which the housing 4 is press-fitted and fixed, and a substrate 8 for supplying power to the drive coil 50.

  Although the bearing member 3 is not limited to this, here, it is formed by sintering powdered metal and is a so-called slide bearing that supports the output shaft 2 while being in contact therewith. The bearing member 3 has a through hole 30 formed in the center. The output shaft 2 is supported by slidably contacting the inner peripheral wall 301 of the through hole 30. The outer peripheral wall 31 of the bearing member 3 has a small diameter portion 311 and a large diameter portion 312.

  The housing 4 is formed by deep drawing of a metal plate such as an iron plate or a steel plate, and has a bottomed cylindrical shape. A recess 401 for inserting the output shaft 2 is formed in the bottom portion 40 of the housing 4, and an annular stopper ring 402 is disposed on the bottom portion 40. After the stopper ring 402 is arranged on the bottom 40 of the housing 4, the stopper ring 402 is prevented from coming off by press-fitting the bearing member 3.

  A concave groove 21 is formed along the circumference of the circumferential curved surface at the end of the output shaft 2. The output shaft 2 passes through the stopper ring 402 by expanding the diameter of the center hole 403 by pushing the output shaft 2 into the center hole 403 formed at the tip of the stopper ring 402. The stopper ring 402 is engaged with the concave groove 21 of the output shaft 2 to suppress the output shaft 2 from coming out of the housing 4.

  FIG. 2 is an enlarged sectional view of a side peripheral portion of the housing of the spindle motor shown in FIG. 1, and FIG. 3 is an AA sectional view of the spindle motor shown in FIG. As shown in FIG. 1, the housing 4 has a cylindrical side peripheral portion 41. As shown in FIGS. 2 and 3, five ridges 42 are formed on the inner peripheral wall 411 in the side peripheral portion 41 of the housing 4 at equal central angular intervals. As shown in FIG. 2, the ridge 42 has a shape extending in the axial direction.

  As shown in FIGS. 2 and 3, a small-diameter portion 311 having a small outer diameter and a large-diameter portion 312 are formed continuously on the outer peripheral wall 31 of the bearing member 3. The outer diameter of the large-diameter portion 312 of the bearing member 3 is formed to be slightly larger than the length from the central axis of the housing 4 to the tip of the ridge 42.

  When the bearing member 3 is press-fitted into the space surrounded by the side peripheral portion 41 of the housing 4, the small diameter portion 311 of the bearing member 3 does not contact the inner peripheral wall 411 and the convex strip 42, so that the convex strip 42 and the large diameter portion 312 are connected. Move until it touches. Thereafter, the large-diameter portion 312 comes into contact with the ridge 42 and the large-diameter portion 312 deforms the ridge 42, so that the bearing member 3 is press-fitted and fixed to the housing 4. At this time, the holding force of the bearing member 3 of the housing 4 can be adjusted by adjusting the length of the ridge 42.

  As shown in FIG. 2, the ridge 42 has a shape extending in the axial direction, and the portion of the outer peripheral wall 412 of the side peripheral portion 41 where the ridge 42 is formed is recessed inside. The housing 4 is press-fitted and fixed in the through hole 51 of the core 5 and the through hole 71 of the base plate 7, and the housing 4 is fixed in contact with the upper portion 413 with respect to the convex shape 42 of the outer peripheral wall 412. Further, the through hole 71 of the base plate 7 is fixed in contact with the lower portion 414 with respect to the ridge 42.

  Here, as shown in FIG. 2, the housing 4 is formed such that the outer diameters of the upper portion 413 and the lower portion 414 of the outer peripheral wall 412 are the same or substantially the same. Since the housing 4 is formed by deep drawing of a metal plate, which will be described later, the accuracy of the shape and outer diameter of the upper part 413 and the lower part 414 of the outer peripheral wall 412 can be increased. The core 5 and the base plate 7 can be fixed to the housing 4 without using them.

  The spindle motor A shown in FIG. 1 supplies an electric power from the substrate 8 to excite the driving coil 50, whereby the rotor magnet 5 is rotated by the permanent magnet 60, and the rotor shaft 5 is press-fitted and fixed to the rotor case 5. 2 and the turntable 1 press-fitted to the output shaft 2 are rotated to rotate the optical disk Ds placed on the turntable 1.

  4A to 4B are schematic views showing an example of a manufacturing process of the spindle motor housing shown in FIG. As shown in FIG. 4, first, the ridges 42 are formed by half punching on a disk-shaped metal plate M1 as a raw material. At this time, five ridges 42 are formed so as to extend in the radial direction from a circle M11 having the same center as the disk-shaped metal plate and having a predetermined radius.

  As shown in FIG. 4B, the pin Pn is pressed from the side from which the protruding strip 42 of the disk-shaped metal plate M1 protrudes, and is pressed into the cylindrical mold Mk to perform deep drawing. At this time, the pin Pn is formed with a groove Pn1 for preventing the protrusion 42 from being deformed when deep drawing is performed. The groove Pn1 extends from the portion where the ridge 42 abuts to the tip of the deep drawing. By forming the groove Pn1 in the pin Pn in this way, after the deep drawing process is completed, the pin Pn is not obstructed when the pin Pn is extracted from the housing 4, so that the pin Pn can be smoothly moved without deforming the protrusion 42. Can be pulled out.

  After the pin Pn is pulled out, the housing 4 remaining in the cylindrical mold Mk has an outer peripheral wall 412 having the same diameter except for a portion where the protruding strips 42 are formed (upper portion 413 and lower portion 414). Is formed.

  When the housing 4 is formed by deep drawing, it is difficult to accurately manufacture both the inner diameter of the inner peripheral wall 411 and the outer diameter of the outer peripheral wall 412 at an arbitrary location of the side peripheral portion 41. In the case of the present invention, as described above, the ridges 42 are previously formed on the flat plate M1 by half punching, so that the height of the ridges 42 can be easily adjusted, and the ridges 42 on the outer peripheral wall 412 are also adjusted. Since parts other than the part where the part is formed are manufactured to have the same outer diameter, high dimensional accuracy is not required for both the inner and outer diameters of the housing as used in the past. It takes less time and can be performed in a shorter time. Moreover, since it is not necessary to make the inner peripheral surface of the cylindrical mold Mk used for deep drawing processing into a special shape, an accurate mold can be easily produced at low cost.

  Although the five protrusions 42 of the housing 4 are provided as an example in which five are provided at equal central angular intervals around the axis, the present invention is not limited to this, and the large-diameter portion 312 of the bearing member 3 is strengthened. The number of pieces that can be held in a wide range can be widely used. Further, the holding force of the bearing member 3 by the housing 4 can be adjusted by adjusting the number, length, and protruding height (height from the inner peripheral wall 411) of the ridges 42. Moreover, although what has protruded with a half punch is demonstrated to the example in order to form the protruding item | line 42, when processing the disk-shaped metal plate M1, what is processed so that the protruding item | line 42 may be formed previously etc. In the case of a circular metal plate, those in which the ridges 42 are formed can be widely used.

  FIG. 5 shows a longitudinal sectional view of another example of the spindle motor according to the present invention. The spindle motor B shown in FIG. 5 has the same configuration as the spindle motor A shown in FIG. 1 except that the shape of the housing 4b is different, and substantially the same parts are denoted by the same reference numerals. As shown in FIG. 5, in the spindle motor B, the protrusion 42b of the housing 4b has a shape divided into two in the axial direction.

  Even if the length of the ridge 42b is long in order to obtain sufficient holding force by dividing the ridge 42b vertically, it is not easily affected by the shape of the ridge 42b by deep drawing, as it is designed. It is possible to exert the holding power of. In the spindle motor B shown in FIG. 5, a description is given of an example in which the protrusion 42 b that is divided in the axial direction is provided, but the invention is not limited thereto, and the spindle motor B may be further finely divided.

  FIG. 6 shows a cross-sectional view of the spindle motor according to the present invention when cut in a direction perpendicular to the axis of still another example. The spindle motor C shown in FIG. 6 has the same configuration as the spindle motor A shown in FIG. 1 except that the shape of the housing 4c is different, and substantially the same parts are denoted by the same reference numerals. As shown in FIG. 6, in the spindle motor C, the protrusions 42c of the housing 4c are divided in the axial direction, and the protrusions 421c on the side close to the bottom 40c and the protrusions 422c on the far side are shifted from each other around the central axis. Has been.

  In the case where the ridges 421c and the ridges 422c are rotated and attached in this way, the large diameter portion 312 of the bearing member 3 comes into contact with the tip portions of the ridges 421c and 422c, so the number of ridges increases. This increases the positioning accuracy of the bearing member 3. Further, since the ridges adjacent in the circumferential direction are formed so as to be shifted in the axial direction, it is difficult to affect the shape of the ridges adjacent in the circumferential direction during deep drawing. As a result, the housing 4c is provided with many ridges and is manufactured with high accuracy, so that the positional accuracy of the bearing member 3 can be raised and held firmly.

  In the spindle motor C shown in FIG. 6, the ridges 42c (421c, 422c) arranged in two stages in the axial direction are described as an example. However, the present invention is not limited to this, and is divided into more stages. It may be.

  As mentioned above, although embodiment of invention was described concretely, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary.

  The optical head of the present invention can be applied to an optical disc apparatus that reads information by irradiating an optical disc such as a DVD, CD, or LD with laser light, or records information on a writable optical disc.

It is sectional drawing of an example of the spindle motor concerning this invention. It is an expanded sectional view of the side periphery of the housing of the spindle motor shown in FIG. It is AA sectional drawing of the spindle motor shown in FIG. It is a schematic perspective view of an example of the manufacturing process of the housing of the spindle motor shown in FIG. It is a longitudinal cross-sectional view of the other example of the spindle motor concerning this invention. It is sectional drawing when cut | disconnecting in the orthogonal | vertical direction with the axis | shaft of the further another example of the spindle motor concerning this invention. It is a longitudinal cross-sectional view of an example of the spindle motor with which the conventional optical disk apparatus is equipped. FIG. 8 is an enlarged cross-sectional view of a portion where a bearing member, a rotor case, and a base plate of the housing of the spindle motor shown in FIG. 7 are press-fitted.

Explanation of symbols

Ds Optical disk A Spindle motor 1 Turntable 2 Output shaft 3 Bearing member 4 Housing 40 Bottom 41 Side periphery 42 Projection 5 Rotor case 50 Driving coil 51 Through hole 6 Core 60 Permanent magnet 61 Through hole 7 Base plate 71 Through hole 8 Substrate

Claims (7)

An output shaft on which a turntable for mounting an optical disc is fitted;
A bearing member that rotatably supports the output shaft;
A bottomed cylindrical housing in which the bearing member is press-fitted and fixed;
A large number of driving coils are attached to the outer peripheral portion at predetermined intervals in the circumferential direction, and the housing is press-fitted and fixed in a through hole formed in the center.
A rotor case that is formed in a bottomed cylindrical shape and is fixed to the inner peripheral surface and press-fits and fixes the output shaft so that the bottom is on the through hole formed in the center of the bottom,
A base plate having a through hole in which the housing is press-fitted and fixed;
A spindle motor that rotates the rotor case by exciting the driving coil and rotationally drives the optical disc via the output shaft and the turntable;
A plurality of ridges extending in the axial direction protruding inward on the inner peripheral wall of the housing and extending in the axial direction whose tip is in pressure contact with the outer periphery of the bearing member are formed at equal central angular intervals. A spindle motor characterized in that a portion into which the through hole of the base plate is press-fitted and a portion into which the through-hole of the base plate is press-fitted have the same outer diameter. An output shaft;
A bearing member that rotatably supports the output shaft;
A bottomed cylindrical housing having a bottom portion into which the bearing member is press-fitted and fixed;
A large number of driving coils are attached to the outer peripheral portion at predetermined intervals in the circumferential direction, and the housing is press-fitted and fixed in a through hole formed in the center.
A rotor case that is formed in a bottomed cylindrical shape and is fixed to the inner peripheral surface and press-fits and fixes the output shaft so that the bottom is on the through hole formed in the center of the bottom,
A spindle motor having a base plate having a through-hole in which the housing is press-fitted and fixed at a center portion, and rotating the rotor case and the output shaft by exciting the driving coil;
The inner peripheral wall of the housing protrudes inward, and a plurality of ridges whose tips are pressed against the outer periphery of the bearing member are formed at equal central angular intervals, and the through-hole of the core is press-fitted into the outer peripheral wall of the housing. The spindle motor is characterized in that the portion to be formed and the portion into which the through hole of the base plate is press-fitted have the same outer diameter.   The spindle motor according to claim 2, wherein the protrusions are arranged in a direction extending to a central axis of the housing.   The spindle motor according to claim 3, wherein the protrusion is formed in a plurality of stages in the axial direction of the housing.   5. The spindle motor according to claim 4, wherein the ridges adjacent to each other in the axial direction are arranged with a predetermined center angle shift in the circumferential direction of the housing.   6. The method for manufacturing a spindle motor according to claim 1, wherein a protrusion is formed in advance on a metal disk, and the protrusion of the metal disk on which the protrusion is formed. A method of manufacturing a spindle motor, wherein deep drawing is performed using a pin having a groove formed in an axial direction at a position corresponding to the ridge from a surface from which the protrusion protrudes.   The spindle motor manufacturing method according to claim 6, wherein the protrusion is formed on the metal disk by a half punch.

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