JP2010166632A - Disk drive unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing structure for a bearing having high rigidity with respect tot external vibrations, with respect to requests for size reduction, thinning, high reliability and high sensitivity of a motor for rotating disk. <P>SOLUTION: The bearing 8, an engaging part 4a and an engaged part 21 are accommodated inside a recess 15, which is formed at the center of a rotor frame 2; an aligning member 3 is attached to the rotor frame 2, while internally surrounding the recess 15, a bearing housing holding part 16 which accommodates and holds at least a half of the axial dimension of a cylinder-shaped part of a bearing housing 9 is integrally formed at a bracket 13; a diameter-expanded part 20 is formed at the upper end of the bearing housing holding part 16; and an angle of the diameter-expanded part 20 is set so that an ultraviolet ray irradiated for making a photocuring adhesive cure, which is filled between and among the diameter-expanded part 20, the bearing housing holding part 16 and the bearing housing 9 is not blocked by the engaged part 21, and penetrates the diameter-expanded part, without fail. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention mainly relates to a disk rotation motor used in a disk drive device that rotates a disk such as an optical disk such as a CD and a DVD, and more particularly to a bearing holding structure and fastening of a bearing holding member.

  Conventionally, a bearing holding structure configured for a disk rotating motor used in a disk drive device that is required to be thin and small is made of a sintered member made of the same material as the bearing, or a brass cutting member. Various types of devices have been proposed, such as those that use bearings, but in order to respond to the rapid price reduction in recent years, it is necessary to construct the bearing holding structure with a combination of as inexpensive members as possible. It has become. At the same time, the demand for reliability is increasing, especially for in-vehicle use, impact resistance and vibration resistance are important requirements, and support for large-capacity media such as Blu-ray. Therefore, the requirements for assembly accuracy are becoming stricter.

A typical structure that combines inexpensive members and ensures high reliability is a structure in which the bearing holding mechanism is composed only of a metal stamped product. Things have been proposed. (For example, see Patent Document 1)
FIG. 4 shows a conventional bearing holding structure described in Patent Document 1. In FIG. 4, the disk rotating motor is composed of a rotor portion 101 and a stator portion 102. The bracket 103 of the stator portion 102 is subjected to burring at its substantially central portion, and the burring portion 104 has a shaft 105 on its inner diameter. The bearing 106 is rotatably supported and functions as a bearing housing.

  A thrust cap 107 that supports the load in the thrust direction of the rotor portion 101 is press-fitted and fixed to the inlet of the burring portion 104 with a thrust plate 108 having wear resistance.

Further, a bearing holding structure has been proposed in which a recess is formed in the center of the bracket and the shaft is supported in the thrust direction at the bottom surface of the recess. (For example, see Patent Document 2)
FIG. 5A shows a conventional bearing holding structure described in Patent Document 2. In FIG. 5A, the disk rotation motor is constituted by a rotor portion 117 and a stator portion 118, and the bracket 119 of the stator portion 118 is fitted with the outer periphery of the bearing housing 120 accommodating and holding the bearing 124 at the substantially central portion thereof. A mating recess 121 is formed, and the bottom surface supports the shaft 123 in the thrust direction via the thrust plate 122. As shown in FIG. 5B, a groove 125 that engages the base end of the bearing housing 120 is formed in the fitting recess 121, and a welding convex portion 126 for welding is formed in the groove 125. Thus, the bracket 119 and the bearing housing 120 are fastened by welding.
JP-A-8-289523 JP 2006-50889 A

  In recent years, disk rotation motors used in disk drive devices have been required to have lower costs, higher reliability, and higher accuracy in addition to further miniaturization and thickness reduction.

However, in the bearing holding mechanism shown in FIG. 4, as the motor becomes smaller and thinner, the length of the thrust cap 108 in the press-fitting axis direction becomes shorter and the fastening strength decreases. Insufficient holding strength to support the load. Even if fixing by bonding is used together, the bonding area becomes small, so that sufficient strength cannot be expected. In addition, the adhesive may flow out to the bearing portion, which may adversely affect reliability. Also, fixing by welding is difficult to implement due to its configuration.

  On the other hand, in the bearing holding mechanism shown in FIG. 5A, the bearing housing 120 accommodating and holding the bearing 124 is fitted and attached to the fitting recess 121 formed in the bracket 119, and the thrust direction of the shaft 123 is fixed by the bracket 119. It is comprised so that a load may be supported. With this configuration, it is possible to increase the support rigidity with respect to the load in the thrust direction of the rotor portion 117, so that high reliability can be obtained. Further, by providing a fitting groove of the bearing housing 120 on the bottom surface of the fitting recess 121 of the bearing housing 120 formed on the bracket 119, the spatter generated during fixing by welding may enter the bearing portion, or It is possible to improve the reliability of welding or fastening by bonding by preventing the intrusion of the adhesive flowing out at the time of fixing by bonding. However, since only the base end of the bearing housing 120 is fastened, there is a possibility that the end face on the output side of the bearing housing 120 will be elastically deformed when vibration is applied, so that an excessive vibration such as in-vehicle use is generated. So it is hard to say that it is highly reliable.

  Further, since the axial dimension of the bearing 124 becomes shorter as the motor becomes smaller and thinner, the bearing life is likely to be reduced due to an increase in the swing of the shaft 123 or an increase in the load applied to the bearing 124. There is a problem of becoming.

  In order to solve the above problems, the present invention provides a rotor frame integrally formed with a turntable portion on which a disk is mounted, an alignment member for centering and supporting the disk, a rotor magnet attached to the rotor frame, and the rotor frame. A rotor portion having a shaft fixed at the center of the shaft, a bearing for supporting the shaft, a cylindrical bearing housing for holding the bearing, a core disposed opposite to the rotor magnet and provided with windings; In a disk rotation motor comprising a stator portion having a bracket for holding a bearing housing, an engaged portion is integrally formed on the axially upper end surface of the bearing housing toward the radially outer side, A retaining member having an engaging portion that engages with the engaged portion is fixed to the rotor frame, and the rotor is A recess for housing a part of the bearing is formed in the center of the inner opening of the ram so as to protrude in the direction opposite to the opening direction, and the engaged portion of the bearing housing and the engaging portion of the retaining member are formed in the recess. The centering member is attached to the rotor frame while containing the concave portion radially inward, and the bracket has a bottomed cylindrical bearing housing holding the cylindrical portion of the bearing housing. The shaft is supported in the thrust direction via a thrust plate inserted in the bottom of the bearing housing holding portion, and the bearing housing holding portion of the bracket is a cylindrical portion of the bearing housing. Is formed so as to accommodate at least one half of the axial dimension of the bearing housing, and between the bearing housing holding portion and the cylindrical portion of the bearing housing, A curable adhesive is filled, and an end portion on the upper side in the axial direction of the bearing housing holding portion is formed with an enlarged diameter portion that expands toward the upper side in the axial direction. The first inclination angle connecting the lower end and the upper end in the axial direction of the portion is the second inclination connecting the lower end in the axial direction of the enlarged diameter portion and the outer periphery of the engaged portion of the bearing housing with respect to the rotation center. It is formed larger than the corner.

  According to the present invention, the bottomed cylindrical bearing housing holding portion that accommodates at least one-half of the axial dimension of the cylindrical portion of the bearing housing is integrally formed in the bracket, and the bearing housing holding portion is provided with a bearing. By adhering and fixing the housing, it is possible to increase the holding rigidity of the bearing without increasing the number of components, and thus it is possible to increase the resistance against excessive vibration typified by in-vehicle use.

  In addition, an enlarged diameter portion is formed at the axially upper end of the bearing housing, and this enlarged diameter portion serves as a reservoir for the adhesive, and the axially lower end and upper end of the enlarged diameter portion with respect to the rotation center are provided. By forming the first inclination angle to be connected larger than the second inclination angle connecting the lower end in the axial direction of the enlarged diameter portion with respect to the rotation shaft and the outer periphery of the engaged portion of the bearing housing, workability as an adhesive is achieved. When UV curable adhesive that provides good and high adhesive strength is used, the irradiated UV light is not blocked by the engaged part of the bearing housing located on the upper side in the axial direction of the enlarged diameter part. It can be penetrated deep into the adhesive application part. Thereby, since an adhesive agent can be hardened reliably, the increase in fastening strength can be expected.

  Furthermore, in a recess formed by projecting in the opposite direction to the opening direction in the center of the inner opening of the rotor frame, a part of the bearing, the engaged part of the bearing housing, and the engaging part of the retaining member are accommodated, By adopting a configuration in which the concave member is included inside the alignment member in the radial direction and attached to the rotor frame, it is possible to reduce the thickness while securing the axial dimension of the bearing.

  In addition, since the bracket can be integrally formed by pressing, the members are relatively inexpensive, the number of parts can be reduced, and the assemblability is improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a structural sectional view of a disk rotation motor according to Embodiment 1 of the present invention. In FIG. 1, a disk rotation motor includes a rotor frame 2 integrally formed with a turntable portion 1 on which a disk is mounted, an alignment member 3 that supports the disk together with the turntable portion 1, and an engagement fixed to the rotor frame 2. A rotor part 7 having a retaining member 4 having a part 4a, a rotor magnet 5 attached to the inner peripheral surface of the rotor frame 2, and a shaft 6 fixed to the center of the rotor frame 2, and a bearing 8 for supporting the shaft 6. A cylindrical bearing housing 9 for holding the bearing 8, a core 12 disposed opposite to the rotor magnet 5 and provided with a winding 11, a bracket 13 for holding the bearing housing 9 and the core 12, and a central bottom portion of the bracket 13. And a stator portion 14 including a thrust plate 10 that supports the shaft 6 in the axial direction.

  The bearing housing 9 is formed into a cylindrical shape by press-molding a plated steel plate, and the bearing 8 is inserted and held inside the cylindrical portion. An engaged portion 21 is integrally formed on the axially upper end surface of the bearing housing 9 toward the radially outer side. The engaged portion 21 engages with the engaging portion 4 a of the retaining member 4, thereby constituting a retaining member that prevents the rotor portion 7 from slipping out of the stator portion 14.

  A recess 15 for housing the bearing 8 is formed in the center of the inner opening of the rotor frame 2 so as to protrude in the direction opposite to the opening direction. The engaged portion 21 and the retaining member 4 of the bearing housing 9 are formed in the recess 15. The engaging part 4a is accommodated. The alignment member 3 is attached to the rotor frame 2 so as to include the recess 15 on the radially inner side. By configuring in this manner, the axial heights of the bearing 8 and the alignment member 3 can be partially overlapped, so that a large axial dimension of the bearing 8 can be secured while achieving a reduction in thickness.

Further, the bracket 13 is made of a magnetic material, and a central portion thereof protrudes upward in the axial direction by press molding, and a stepped portion 17 that determines the height direction of the core 12 and a cylindrical portion 18 that determines the radial position of the core 12; Further, a flat portion 19 is formed, and the bearing housing holding portion 16 is formed by folding back downward in the axial direction and projecting into a bottomed bag shape. A thrust plate 10 is inserted into the bottom of the bearing housing holding portion 16, and the shaft 6 is supported in the thrust direction via the thrust plate 10. With this configuration, like the conventional disk rotation motor shown in FIGS. 5A and 5B, the support rigidity of the rotor portion 7 against the load in the thrust direction can be increased.

  Here, the bearing housing holding portion 16 is formed so as to accommodate at least one half of the axial dimension of the cylindrical portion of the bearing housing 9, and is interposed between the bearing housing holding portion 16 and the cylindrical portion of the bearing housing 9. Is filled with a light curable adhesive (for example, an ultraviolet curable adhesive), cured by ultraviolet irradiation and fastened, and has a configuration that increases rigidity against an external force in the radial direction. An attracting magnet 22 that attracts the rotor frame 2 in the thrust direction is attached to the flat portion 19, and the bracket 13 forms a magnetic path thereof. Further, an enlarged diameter portion 20 that increases in diameter toward the upper side in the axial direction is formed at an end portion on the upper side in the axial direction of the bearing housing holding portion 16 to form a reservoir for adhesive.

  FIG. 2 shows a step of irradiating the ultraviolet curable adhesive filled between the enlarged diameter portion 20 and the bearing housing holding portion 16 and the cylindrical portion of the bearing housing 9 by irradiating with ultraviolet V. Before the insertion of the rotor portion 7 of the disk rotation motor shown in FIG. As shown in FIG. 2, the enlarged diameter portion 20 is configured such that the irradiated ultraviolet ray V is not blocked by the engaged portion 21 of the bearing housing 9 positioned on the axially upper side of the enlarged diameter portion 20. Ultraviolet rays V can be penetrated deep into the adhesive application part. Therefore, the first inclination angle θ1 connecting the lower end and the upper end in the axial direction of the enlarged diameter portion 20 with respect to the center of rotation is such that the lower end in the axial direction of the enlarged diameter portion 20 and the bearing housing 9 are engaged with the rotational axis. It is formed larger than the second inclination angle θ2 connecting the outer periphery of the portion 21. Thereby, since an adhesive agent can be hardened reliably, the increase in fastening strength can be expected.

  Further, the base end portion on the lower side in the axial direction of the bearing housing 9 is bent radially inward to form an L-shaped portion 9 a, and the L-shaped portion 9 a is brought into close contact with the bottom portion of the bearing housing holding portion 16 of the bracket 13. As a result, the airtightness of the adhesive application portion is increased, and the adhesive can be prevented from flowing into the bearing 8. Further, when the photo-curing adhesive has anaerobic properties, the adhesive filled in the gap between the cylindrical portion of the bearing housing 9 and the bearing housing holding portion 16 can be reliably cured. .

(Embodiment 2)
3A and 3B show a disk rotation motor according to Embodiment 2 of the present invention.
3A is a cross-sectional view of the main part, and FIG. 3B is a plan view of the main part.

  As shown in FIGS. 3A and 3B, the difference from the disk rotating motor of the first embodiment shown in FIG. 1 is that the bearing on the bottom surface of the bearing housing holding portion 16 formed on the bracket 13. A plurality of through holes 23 are formed in the vicinity of the surface with which the L-shaped portion 9a of the housing 9 contacts. With this configuration, the ultraviolet curable adhesive filled in the gap between the bearing housing holding portion 16 and the bearing housing 9 from the enlarged diameter portion 20 of the bearing housing holding portion 16 is applied to the bottom surface portion of the bearing housing holding portion 16 by capillary action. When the L-shaped portion 9a of the bearing housing 9 penetrates to the surface to be contacted, it can be reliably cured by irradiating the ultraviolet ray V from the lower side of the bracket 13 through the through hole 23. A further increase in fastening strength can be expected.

  It is useful for brushless motors for mobile devices and in-cars that require high reliability, high accuracy, and low price in addition to miniaturization and thinning, such as spindle motors for optical media.

Sectional view of the structure of the disk rotation motor according to the first embodiment of the present invention. Sectional drawing of the principal part of the disk rotation motor which concerns on Embodiment 1 of this invention (A) Main part sectional drawing of the disk rotation motor which concerns on Embodiment 2 of this invention, (b) Main part top view of the disk rotation motor which concerns on Embodiment 2 of this invention Structural sectional view showing a conventional disk rotation motor (1) (A) Structural sectional view showing a conventional disk rotation motor (2), (b) Perspective view of a main part of a conventional disk rotation motor

DESCRIPTION OF SYMBOLS 1 Turntable part 2 Rotor frame 3 Alignment member 4 Retaining member 4a Engagement part 5 Rotor magnet 6, 105, 123 Shaft 7, 101, 117 Rotor part 8, 106, 124 Bearing 9, 120 Bearing housing 9a L-shape Part 10, 108, 122 Thrust plate 11 Winding 12 Core 13, 103, 119 Bracket 14, 102, 118 Stator part 15 Recess 16 Bearing housing holding part 17 Step part 18 Cylindrical part 19 Flat part 20 Enlarged part 21 Engaged Part 22 Suction magnet 23 Through hole 104 Burring part 107 Thrust cap 121 Fitting concave part 125 Groove part 126 Welding convex part V Ultraviolet rays θ1, θ2 Inclination angle

Claims (4)

A rotor frame having a rotor frame integrally formed with a turntable for mounting a disk, a centering member for centering and supporting the disk, a rotor magnet attached to the rotor frame, and a shaft fixed to the center of the rotor frame A stator portion, a bearing that supports the shaft, a cylindrical bearing housing that holds the bearing, a core that is disposed opposite to the rotor magnet and that is wound, and a bracket that holds the bearing housing In the disk rotation motor, the engaged portion is integrally formed on the axially upper end surface of the bearing housing toward the radially outer side, and the engaged portion is formed on the rotor frame. A retaining member formed with an engaging portion to be engaged is fixed, and the shaft is arranged at the center of the inner opening of the rotor frame. A recess for housing a part of the bearing housing is formed protruding in the direction opposite to the opening direction, and the engaged portion of the bearing housing and the engaging portion of the retaining member are accommodated in the recess, and the alignment member has a diameter It is attached to the rotor frame while containing the concave portion inside in the direction, and a bottomed cylindrical bearing housing holding portion for accommodating and holding the cylindrical portion of the bearing housing is integrally formed on the bracket. The shaft is supported in the thrust direction via a thrust plate inserted in the bottom of the holding portion, and the bearing housing holding portion of the bracket is at least one half of the axial dimension of the cylindrical portion of the bearing housing. The space between the bearing housing holding portion and the cylindrical portion of the bearing housing is filled with a photocurable adhesive, An end portion on the upper side in the axial direction of the bearing housing holding portion is formed with a diameter-expanding portion that increases in diameter toward the upper side in the axial direction. The first rotation angle to be connected is a disk rotation motor that is formed to be larger than the second inclination angle that connects the lower end in the axial direction of the enlarged diameter portion with respect to the rotation center and the outer periphery of the engaged portion of the bearing housing. An axially lower base end portion of the bearing housing is folded radially inward to form an L-shaped portion, and the L-shaped portion and the bottom portion of the bearing housing holding portion are brought into contact with each other. 2. The disk rotation motor according to 1. 3. The disk rotation motor according to claim 1, wherein a plurality of through holes are formed in the vicinity of the bearing housing base end portion at the bottom of the bearing housing holding portion. A disk drive device on which the disk rotation motor according to any one of claims 1 to 3 is mounted.

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