JP2000116092A - Spindle motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture at low cost, while easily forming positioning projections at specified places and to obtain high rotation accuracy. SOLUTION: A motor bracket 1 is constituted of a base member 2, manufactured by machining and a plate-like member 3 manufactured by press working the sheet metal material and provided with positioning projections 13, 14. The positioning projections 13 of the plate-like member 3 are for positioning a connector 12 at a specified place and the positioning projections 14 are for positioning a motor at a specified place in equipment where the motor is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor used for rotating a recording disk such as a hard disk (magnetic disk).

[0002]

2. Description of the Related Art As a spindle motor used for this kind of application, for example, a general structure is disclosed in Japanese Patent Application Laid-Open No. 7-312841. The structure of this spindle motor is briefly described as follows. It is. That is, the shaft is fixed to the central base portion of the fixed-side motor bracket in an upright state in which the shaft protrudes upward. A hard disk is fitted on the outer peripheral surface of the shaft so as to be rotationally driven. A cylindrical rotor hub is rotatably supported via a pair of upper and lower bearings. A stator is fixedly held on the motor bracket in a concentric arrangement with the shaft. A cylindrical rotor yoke is fixed to the lower portion of the outer peripheral end of the rotor hub, and a rotor magnet is mounted on the inner peripheral surface of the rotor yoke so as to face the stator with a small gap.

[0003]

Since a spindle motor for rotationally driving a recording medium such as a hard disk requires extremely high rotational accuracy, each component requires high-precision processing and assembly. In particular, since the motor bracket of the motor has a great influence on the rotation accuracy, it is generally manufactured as an integral body by precisely cutting a material such as aluminum.

[0004] For this reason, the motor bracket requires complicated and high-precision cutting work in its manufacture, so that the number of steps is increased and the processing cost is increased. Moreover, since this is manufactured by cutting the motor bracket,
It is difficult to form positioning projections and the like at predetermined locations to facilitate assembly. Therefore, it is difficult to attach a connector to a predetermined position of a motor bracket or to attach a motor bracket to a predetermined position of a base member in a recording medium driving device such as a recording disk device, which takes time and increases the number of assembling steps. This high processing cost and a large number of man-hours are factors that hinder cost reduction of the spindle motor and the recording medium driving device.

[0005] Separately, a so-called base, in which a fixed member of a spindle motor is directly attached to a base member of a recording medium driving device which rotationally drives a recording medium such as a hard disk without interposing a member such as a motor bracket. Although there is a recording medium driving device having a body shape, in such a recording medium driving device having an integrated base, the positional relationship in the height direction between a spindle motor and other members constituting the recording medium driving device is precisely defined. It is necessary to precisely process the reference surface for cutting by a cutting process, and requires a precise and complicated process like the motor bracket of the conventional spindle motor. This is one of the factors that hinders the cost reduction of the medium drive device.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. It is an object of the present invention to make it possible to easily form positioning projections and the like at required places and to manufacture them at low processing cost, and to obtain high rotational accuracy. An object of the present invention is to provide a spindle motor having a motor bracket or a base member having a structure capable of obtaining the above.

[0007]

In order to achieve the above object, a spindle motor according to the present invention comprises a motor bracket, a rotor hub rotatable relative to the motor bracket, and a rotor hub fixed to the rotor hub. The motor bracket includes a rotor magnet and a stator opposed to the rotor magnet at a predetermined gap. The base member is formed by a cutting process and disposed at a central portion. And a mounting member disposed around the base member, and the base member is fitted and fixed in a mounting hole at the center of the mounting member to form an integrated structure. ing.

In this spindle motor, the motor bracket has a structure in which a base member and a mounting member are connected to each other, and most of the motor bracket can be constituted by a mounting member that can be manufactured by simply pressing a sheet metal material. It is possible to adopt a structure in which a base member that requires complicated and high-precision cutting is provided only in a portion. Therefore, the motor bracket is much easier to manufacture than the conventional spindle motor, so that the number of manufacturing steps is reduced and the processing cost can be greatly reduced. Furthermore, since various positioning projections can be easily formed on the mounting member by pressing,
Assembly man-hours can be reduced. By reducing the machining cost of the motor bracket and the number of assembly steps, considerable cost reduction can be achieved. In addition, the central portion of the motor bracket at which the shaft, bearing or stator, which affects the rotation accuracy, to be fixed is formed of a base member obtained by cutting a material such as aluminum similarly to the conventional motor bracket. Therefore, high rotational accuracy can be secured.

In the above invention, it is preferable that the mounting member has a configuration in which at least a positioning projection for positioning the connector at a predetermined position is formed.

Thus, when assembling the motor,
Easy and accurate positioning and mounting of the connector to the mounting member of the motor bracket can greatly reduce the number of assembly steps.

In the case where the stator and the connector are electrically connected via the flexible circuit board, the connector and the flexible circuit board can be integrally positioned by the positioning projections after connecting the connector and the flexible circuit board.
The number of assembly steps can be significantly reduced.

In addition, by assembling the spindle motor into the recording medium driving device, the positioning member is provided with a positioning projection for positioning the motor-using device with respect to the base member. Since it can be accurately positioned and mounted, the number of assembly steps can be further reduced.

[0013] In the above invention, the base member has a projection formed on an outer peripheral portion of a fitting portion fitted into the mounting hole of the mounting member, and the mounting member has a hole edge of the mounting hole. A plurality of fixing holes are formed in the portion, and after the motor bracket is fitted into the mounting hole, the protrusion is plastically deformed by caulking to be fitted into the fixing hole. The base member and the mounting member can be integrally formed.

[0014] Thus, the base member and the mounting member can be integrally joined in a state without play by preventing the rotation by fitting the protrusion of the base member into the fixing hole of the mounting member, and thus rotating the base member and the mounting member. High rotational accuracy as a motor can be maintained even though the motor bracket that affects the accuracy is configured by combining two separate members.

Another spindle motor of the present invention is:
A base member, a rotor hub rotatable relative to the base member, a rotor magnet fixed to the rotor hub, and a stator opposed to the rotor magnet at a predetermined gap; The member is formed by cutting and pressed into a sheet metal material, and is integrally formed by being fixedly fitted into the mounting hole of a base member of a motor-using device having at least one positioning projection and a mounting hole formed therein. It is characterized by.

In another spindle motor of the present invention,
In a so-called base-integrated spindle motor in which a base member, which is a fixed member of the motor, is directly fixed to a base member of a device using the motor, at least one positioning projection and a mounting hole can be formed by press working. Therefore, the number of assembling steps of the motor-using device can be reduced, and the cost can be reduced.

Accordingly, when assembling the motor,
Easy and accurate positioning and mounting of the connector to the mounting member of the motor bracket can greatly reduce the number of assembly steps.

When the stator and the connector are electrically connected to each other via the flexible circuit board, the connector and the flexible circuit board can be integrally positioned by the positioning projections after connecting the connector and the flexible circuit board.
The number of assembly steps can be significantly reduced.

In the above invention, the base member has a projection formed on an outer peripheral portion of a fitting portion fitted into the mounting hole of the base member, and the base member has a hole edge of the mounting hole. A plurality of fixing holes are formed in the portion, and the base member, after fitting the fitting portion into the mounting hole, plastically deforms the protrusion by crimping and fits into the fixing hole. Thereby, the base member and the base member can be integrally formed.

Accordingly, the base member and the base member are
By fitting the protrusion of the base member into the fixing hole of the base member, the base member can be prevented from rotating and can be integrally connected without backlash, so that high rotational accuracy as a motor can be maintained.

[0021]

Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a spindle motor according to an embodiment of the present invention, and FIG. 2 is a bottom view thereof. In these figures, in the motor bracket 1 of the spindle motor, a fitting portion 15 protruding from a lower center portion of the base member 2 is inserted into a central circular mounting hole 4 of the disk-shaped mounting member 3. It has an integrated configuration. A shaft 7 is press-fitted into a fixing hole 8 at the center of the base member 2 and is fixed in an upright state. A cylindrical supporting protruding wall 9 is formed concentrically with the fixing hole 8 from a peripheral end of the upper surface. In the arrangement, they are integrally protruded upward. Further, on the lower surface of the fitting portion 15 of the base member 2, an annular groove 10 is formed integrally with an intermediate portion, and an annular protrusion 11 is formed integrally with an outer peripheral portion outside the annular groove 10. This base member 2
Since it is a part that directly affects the rotation accuracy of the motor, it is manufactured by precisely cutting a material such as aluminum similarly to a motor bracket of a conventional spindle motor.

Mounting member 3 in motor bracket 1
Is formed by pressing a disk-shaped sheet metal material using a press die. As shown in FIG. 2, the mounting member 4 is formed by punching the mounting hole 4 at the center thereof, and has a 90 ° angle at the hole edge of the mounting hole 4.
Semicircular fixing holes 21 are formed at four places in the interval. After inserting the lower center fitting portion 15 of the base member 2 into the mounting hole 4 of the mounting member 3, the motor bracket 1 faces the fixing hole 21 of the annular protrusion 11 of the base member 2. The base member 2 and the mounting member 3 are integrally connected to each other in a state where the base member 2 and the mounting member 3 are prevented from rotating by being plastically deformed by crimping and fitted into the fixing holes 21.

The mounting member 3 includes a connector 12
A pair of positioning projections 13 for positioning the spindle motor at a predetermined mounting position, three positioning projections 14 for positioning the spindle motor at a predetermined position of the base member in the recording medium driving device, and the spindle motor are fixed to the base member. Holes 15 are formed by pressing. Further, as shown in FIG. 1, a mounting hole 18 is formed at an appropriate position of the mounting member 3 by punching, and a drawer bush 17 is fixedly fitted in the mounting hole 18.

A stator 22 formed by winding a stator coil 23 around a stator core 24 is externally fitted and fixed to an outer peripheral portion of the cylindrical supporting projection wall 9 of the base member 2. A lead wire (not shown) of the stator coil 23 is drawn out to the lower side of the mounting member 3, that is, outside the motor, through a drawing hole of the drawing bush 17 fixedly fitted in the mounting hole 18 of the mounting member 3 in the motor bracket 1. At the same time, it is fixed to the terminal area of the flexible circuit board 19 adhered to the lower surface of the mounting member 3 by the solder 20 and is electrically connected thereto. As shown in FIG. 2, the connector 12 is connected to the flexible circuit board 19, and the flexible circuit board 19 is electrically connected to an external board (not shown) via the connector pins 39 of the connector 12.

The rotor hub 27 for integrally rotating and driving a hard disk (not shown) has a substantially cylindrical shape as a whole, and has an inner cylindrical wall portion 28 arranged along the inner peripheral portion thereof. In addition, a disk mounting surface 29 for externally fixing the hard disk is formed. The rotor hub 27 has an inner peripheral wall portion 28 rotatably supported on the outer peripheral surface of the support shaft 7 with a pair of upper and lower ball bearings 30 and 31 interposed therebetween.

The upper ball bearing 30 has an annular holding step 3 formed by cutting out the inner peripheral surface of the base of the rotor hub 27.
In a state where the outer ring 30a is positioned in contact with the upper part 2 from above, the outer ring 30a is bonded to the inner peripheral surface of the base of the rotor hub 27 with an adhesive, and the inner ring 30b is fixed to the outer peripheral surface of the shaft 7 with an adhesive. On the other hand, the lower ball bearing 31
The outer ring 31a is fixed to the inner peripheral wall 28 with an adhesive in a state in which the outer ring 31a is positioned by contacting the outer ring 31a from below to the annular holding step 33 formed by cutting out the inner circumferential surface of the base of the rotor hub 27. And the inner ring 31b is
Is bonded to the outer peripheral surface with an adhesive. The upper end opening of the rotor hub 27 is closed by a cap 34.

The outer peripheral surface of the rotor hub 27 has a mounting projection 35 projecting outward. A cylindrical rotor yoke 37 is fixed to the lower surface of the mounting projection 35 in a suspended state, and a cylindrical rotor magnet 38 internally fitted and fixed to the rotor yoke 37 has a predetermined gap in the radial direction with respect to the stator core 24. And are arranged facing each other.

In this spindle motor, a magnetic action is generated between the stator 22 and the rotor magnet 38 by energizing the stator coil 23 of the stator 22 from the external board through the connector 12, the flexible circuit board 19, and the coil drawer. The rotor hub 27 rotates with the shaft 7 as a rotation support shaft. This allows
The hard disk that is externally fitted to the rotor hub 27 and supported on the disk mounting surface 29 is driven to rotate integrally with the rotor hub 27.

In this spindle motor, since the motor bracket 1 has a structure in which the base member 2 and the mounting member 3 are joined separately, most of the structure is obtained by simply pressing a sheet metal material. The mounting member 3 to be manufactured occupies, and the base member 2 that requires complicated and high-precision cutting is provided only in the central portion. Therefore, the motor bracket 1 is much easier to manufacture than a conventional motor bracket that manufactures all of the spindle motors by cutting, so that the number of manufacturing steps is reduced and the processing cost can be greatly reduced.

Further, the mounting member 3 includes a positioning projection 13 for positioning the connector 12 connected to the flexible circuit board 19, and a motor bracket 1 for assembling a recording medium drive using a spindle motor as a rotation drive source. Positioning projection 1 for positioning the base member on the base member
4 can be easily formed by press working.
As a result, the spindle motor itself is significantly easier to assemble and assemble into the recording medium drive, thereby reducing the number of assembly steps. Cost reduction can be achieved.

In addition, the central portion of the motor bracket 1 for fixing the shaft 7 and the stator 22 which affects the rotation accuracy is the same as the conventional motor bracket.
The base member 2 is obtained by cutting a material such as aluminum. The base member 2 and the mounting member 3 are formed by fitting a fitting portion 15 of the base member 2 into the mounting hole 4 of the mounting member 3 and then caulking a required portion of the annular projection 11 of the base member 2. The fixing hole 2 of the mounting member 3
By being fitted into the unit 1, they are integrally connected in a state where they are prevented from rotating. As a result, the spindle motor can ensure extremely high rotational accuracy, although a significant cost reduction can be achieved.

FIG. 3 is a sectional view showing a second embodiment of the spindle motor according to the present invention. In the first embodiment, the present invention is applied to a fixed shaft type spindle motor. In the second embodiment, the present invention is applied to a shaft rotating type motor. In the second embodiment, members that are substantially the same as those in the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof is omitted.

Referring to FIG. 3, in the second embodiment, a motor bracket 1B serving as a base body of a spindle motor is provided such that a fitting portion 15B of a base member 2B is provided at the center of a substantially bowl-shaped mounting member 3B. It is configured to be inserted into the circular mounting hole 4B and integrated. The mounting member 3B is formed by pressing a plate-shaped member, the base member 2B is formed by cutting, and a cylindrical support portion 40 is integrally provided on the base member 2B. A shaft 7B is fixed to the rotor hub 27B, and the shaft 7B is connected to a pair of ball bearings 30, 31.
And is rotatably supported by the cylindrical support portion 40 via. The lower end opening of the base member 2B is closed by a cap member 34B.

In this embodiment, the rotor hub 27
The mounting projection 35B protruding from the outer surface of the outer peripheral portion of B has a substantially L-shaped cross-sectional shape, and its radially outer end hangs down toward the motor bracket 1B. The rotor yoke 37 is fitted on the inner surface of the hanging part of the mounting projection 35B. Other basic configurations of the second embodiment are substantially the same as those of the first embodiment.

Although the embodiment of the spindle motor according to the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications and corrections can be made without departing from the scope of the present invention. It is.

For example, in the illustrated embodiment, the present invention is applied to a motor using a ball bearing as a bearing. However, the present invention is not limited to this, and is similarly applied to a motor using a hydrodynamic bearing as a bearing. can do.

Also, the spindle motor according to the present invention
The present invention is also applicable to a so-called base-integrated spindle motor in which a base member, which is a fixed member of a motor, is directly fixed to a base member of a motor-using device.

[0038]

As described above, according to the spindle motor of the present invention, since the motor bracket has a structure in which the base member and the mounting member are joined, most of the motor bracket simply presses the sheet metal material. The motor bracket can be configured with a mounting member that can be machined and manufactured, and a base member that requires complicated and high-precision cutting can be provided only in the center part. Compared with this, the production becomes much easier, the number of production steps is reduced, and the processing cost can be greatly reduced. Further, since various positioning projections can be easily formed on the mounting member by press working, the number of assembly steps can be reduced, so that considerable cost reduction can be achieved. In addition, the central part of the motor bracket where the shaft, ball bearing or stator, etc., which affects the rotation accuracy, is fixed with a base member obtained by cutting a material such as aluminum, like the conventional motor bracket. Therefore, high rotational accuracy can be ensured.

According to another spindle motor of the present invention, various positioning projections and mounting holes can be easily formed by press working on the base member of the equipment using the motor.
Since the number of assembly steps can be reduced, a considerable cost reduction can be achieved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a spindle motor according to a first embodiment of the present invention.

FIG. 2 is a bottom view of the spindle motor.

FIG. 3 is a longitudinal sectional view showing a spindle motor according to a second embodiment of the present invention.

[Description of Signs] 1, 1B Motor bracket 2, 2B Base member 3, 3B Mounting member 4, 4B Mounting hole 7, 7B Shaft 8 Fixing hole 9 Support protruding wall 11 Annular protrusion (protrusion) 12 Connector 13 Positioning protrusion 14 Positioning Protrusion 15, 15B Fitting Part 21 Fixing Hole 22 Stator 27, 27B Rotor Hub 30, 31 Ball Bearing (Bearing) 38 Rotor Magnet

Claims (9)

[Claims] A motor bracket, a rotor hub rotatable relative to the motor bracket, a rotor magnet fixed to the rotor hub, and a stator opposed to the rotor magnet with a predetermined gap. In the spindle motor, the motor bracket is formed by a cutting process, and a base member arranged at a central portion; and a sheet metal material is pressed to form at least one positioning protrusion, and the motor bracket is formed around the base member. A spindle motor having a mounting member disposed therein, wherein the base member is fitted and fixed in a mounting hole at the center of the mounting member and integrated. 2. The spindle motor according to claim 1, wherein the positioning projection formed on the mounting member is a positioning projection for positioning a connector at a predetermined position. 3. The stator according to claim 1, wherein the stator is electrically connected to the connector through a flexible circuit board, and the flexible circuit board and the connector are integrally positioned by a positioning protrusion formed on the mounting member. Item 3. A spindle motor according to item 2. 4. The spindle motor according to claim 1, wherein the positioning protrusion formed on the mounting member is a positioning protrusion for positioning with respect to a base member to be mounted when assembling a device using the motor. 5. The base member has a protrusion formed on an outer peripheral portion of a fitting portion fitted into the mounting hole of the mounting member, and the mounting member has a hole edge of the mounting hole. A plurality of fixing holes are formed in the motor bracket, and after the fitting portion is fitted into the mounting hole, the protrusion is plastically deformed by caulking and fitted into the fixing hole, 2. The apparatus according to claim 1, wherein the base member and the mounting member are integrated.
5. The spindle motor according to any one of items 1 to 4. 6. A base member, a rotor hub rotatable relative to the base member, a rotor magnet fixed to the rotor hub, and a stator opposed to the rotor magnet with a predetermined gap. In the spindle motor provided, the base member is formed by cutting, and a sheet metal material is pressed to form at least one positioning protrusion and a mounting hole. A spindle motor, wherein the base member is integrated by being fitted and fixed. 7. The spindle motor according to claim 6, wherein the positioning projection formed on the base member is a positioning projection for positioning a connector at a predetermined position. 8. The stator, wherein the stator is electrically connected to the connector through a flexible circuit board, and the flexible circuit board and the connector are integrally positioned by a positioning protrusion formed on the mounting member. Item 8. A spindle motor according to item 7. 9. The base member has a projection formed on an outer peripheral portion of a fitting portion fitted into the mounting hole of the base member, and the base member has a hole edge of the mounting hole. A plurality of fixing holes are formed in the base member, and after the fitting portion is fitted in the mounting hole, the protrusion is plastically deformed by caulking to be fitted in the fixing hole. 9. The apparatus according to claim 6, wherein said base member and said base member are integrated.
A spindle motor according to item 1.