JPH06339254A - Assembly method for spindle motor - Google Patents

Abstract

PURPOSE:To provide an assembly method for a spindle motor capable of very accurately processing a disk mounting portion. CONSTITUTION:In a spindle motor assembly method, a rotor magnet 30 and a york 31 are fixed to a rotor hub 11, and an outer ring 32a of a first bearing 32 is adhered and fixed to the inside of a center hole 24. Next, an inner ring 33b of a second bearing 33 is adhered and fixed to a predetermined position of a center spindle 14. And the center spindle 14 is inserted from a lower portion of a center hole 24 to the inside of the inner ring 32b and adhered and fixed, and the outer ring 33a is adhered and fixed to the inner periphery of the center hole 24. When adhering and fixing this, a load W is applied to the inner ring 32b of the bearing 32. In this state, cutting work is performed for a ring-shaped overhang 28 which is a mounting surface for a magnetic disk. Assembly at the stationary member side is carried out at the same time with the process, a stator core formed by winding a stator coil around a bracket is fixed and then the center spindle 14 is fixed to the hole of the bracket thereby completing the assembly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor assembling method.

[0002]

2. Description of the Related Art Conventionally, a brushless polyphase DC motor has been used as a motor for rotating a magnetic disk drive. This kind of motor is also called a spindle motor, and as a basic configuration, a stationary member having a stator coil that generates a current magnetic field in an excited state, and a magnetic force of the stator coil to obtain a rotational force by electromagnetic interaction with the current magnetic field. And a rotating member having a rotor magnet.

In the spindle motor having such a structure,
In order to meet such a demand, it is usually required to prevent the rotation error of the magnetic disk mounted on the rotating member side. In the state in which is mounted on the stationary member, the stationary member side is supported, and the magnetic disk mounting portion of the rotating member is cut to secure the processing accuracy.

However, such a conventional spindle motor assembling method has the following technical problems.

[0005]

That is, in the above-described conventional spindle motor assembling method, the rotating member is assembled to the stationary member, and the magnetic disk mounting portion of the rotating member is processed at the stage when the assembly of the motor is almost completed. Therefore, it is possible to eliminate the assembly error, but when the spindle motor is assembled, there is almost no portion protruding to the outside, and it becomes difficult to support it during cutting.

Further, in the case where the bracket functions as the base member of the disk drive, the bracket itself is large and the shape thereof is substantially rectangular, so that the cutting process is difficult in this case as well. Therefore, it is extremely difficult to secure the processing accuracy of the mounting portion of the magnetic disk, and there is a problem that the production efficiency of the motor is reduced.

The present invention has been made in view of the above problems, and an object thereof is to make it possible to easily secure the processing accuracy of the mounting portion of the magnetic disk and to improve the production efficiency of the motor. It is to provide a method of assembling a motor.

[0008]

In order to achieve the above object, the present invention rotates by electromagnetic interaction between a stationary member to which a stator coil for generating a current magnetic field in an excited state is mounted and the current magnetic field of the stator coil. In a method of assembling a spindle motor having a rotating member to which a rotor magnet for obtaining force is attached, and a bearing portion provided between the stationary member and the rotating member, the stationary member includes a bracket to which the stator coil is attached. A central shaft portion fixed to the bracket, and a step of attaching the central shaft portion to the rotating member via the bearing member before fixing the central shaft portion to the bracket.

In the above assembling method, the bearing portion is composed of a pair of first and second ball bearings arranged vertically along the axial direction of the central shaft portion, and an outer ring of the first ball bearing is formed. After fixing to the rotating member and fixing the inner ring of the second ball bearing to the central shaft portion, the inner ring of the first ball bearing is adhesively fixed to the central shaft portion and the outer ring of the second ball bearing is fixed. It can be adhesively fixed to the rotating member.

[0010]

According to the spindle motor assembling method having the above structure, the stationary member has the bracket to which the stator coil is attached and the central shaft portion fixed to the bracket, and the central shaft portion is fixed to the bracket. Since it includes the step of attaching to the rotating member via the bearing member, at this stage, the fixed portion of the central shaft portion to the bracket can be supported and the magnetic disk mounting portion of the rotating member can be cut. it can.

According to the second aspect of the invention, also in the spindle motor having a pair of ball bearings arranged in a stepwise manner with respect to the central shaft portion, the fixed portion of the central shaft portion to the bracket is supported. Thus, the magnetic disk mounting portion of the rotating member can be cut.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. 1 to 5 show an embodiment of a method of assembling a spindle motor according to the present invention. The spindle motor shown in the same figure is a shaft fixed type DC motor, as shown in the completed state of assembly in FIG. 5, and includes a stationary member (stator) 10, a rotating member (rotor hub) 11, and a bearing portion 12. have.

The stationary member 10 is composed of a bracket 13 and a central shaft portion 14. The bracket 13 includes a flat plate-shaped base portion 15 and a tubular portion 1 protruding from the center of the base portion 15.
6, a hole 17 at the center of the tubular portion 16 that vertically penetrates the tubular portion 16, and a step portion 18 formed on the outer periphery of the tubular portion 16.
And an annular convex portion 19 provided on the outer circumference of the hole portion 17, and an annular flange portion 20 provided on the outer circumference of the base portion 15.

In the motor shown in this embodiment, the bracket 13 is attached to the base member (not shown) of the disk drive device, but the bracket 13 itself may function as the base member. An annular stator core 21 formed of a laminated body is fixedly mounted on the step portion 18 provided on the outer periphery of the tubular portion 16, and a stator coil 22 is wound around the stator core 21.

The rotor hub 11 has a cylindrical base portion 23,
A central hole 24 which is located at the center of the base portion 23 and which vertically penetrates the base portion 23, and an annular projecting portion 25 which is provided so as to project from the inner surface of the central hole 24.
An annular protruding portion 26 protruding from the lower surface of the base portion 23, an annular wall portion 27 protruding from the upper surface of the base portion 23, an annular protruding portion 28 protruding from the lower end of the outer peripheral surface of the base portion 23, An annular cutout 29 is provided on the lower surface of the annular overhang 28.

An annular rotor yoke 30 is fixed to the annular cutout 29 of the rotor hub 11, and a rotor magnet 32 is fixed to the inner peripheral surface of the rotor yoke 30 so as to face the stator core 21. ing. The bearing member 12 includes the first and second ball bearings 3
2, 33, each ball bearing 32, 33
Has outer rings 32a and 33a, inner rings 32b and 33b, and balls 32c and 33c.

In FIG. 5, a member indicated by reference numeral 34 is a flexible printed circuit board for supplying a predetermined direct current to the stator coil 22, and this board 3
4 is adhesively fixed on the surface of the base portion 15 of the bracket 13. In the spindle motor of this embodiment, a magnetic disk (not shown) is mounted on the upper surface of the overhanging portion 28 of the rotor hub 11, and strict machining accuracy is required for processing the upper surface of the overhanging portion 28. Therefore, in this embodiment, a method of assembling the spindle motor is devised so that the protruding portion 28 of the rotor hub 11 can be easily cut.

That is, in the spindle motor assembling method of this embodiment, first, the first step shown in FIG. 1 is performed.
The first step shown in the figure is the annular notch 2 of the rotor hub 11.
9, a rotor yoke 30 to which a rotor magnet 31 is fixed is fixed, a first ball bearing 32 is inserted into the center hole 24, and an outer ring 32a of the first ball bearing 32 is adhesively fixed to the inner peripheral surface of the center hole 24.

At this time, the outer ring 32a is positioned and fixed so that the lower surface of the outer ring 32a of the first ball bearing 32 contacts the upper surface of the annular protrusion 25. The rotor yoke 30 may be fixedly mounted after the outer ring 32a of the first ball bearing 32 is bonded and fixed without any problem.
Then, the second step shown in FIG. 2 is performed simultaneously with or before or after the first step. In this second step, the inner ring 3 of the second ball bearing 33 is placed at a predetermined position of the central shaft portion 14 whose one end is fitted and fixed in the hole portion 17 of the bracket 13.
3b is adhesively fixed. The adhesive fixing position of the inner ring 33b is a position where the upper end of the outer ring 33a abuts the lower surface of the annular protruding portion 25 of the rotor hub 11 when the central shaft portion 14 is fixed to the bracket 13, and a dedicated positioning jig is used in advance. It is manufactured and positioned using this positioning jig.

When the pair of ball bearings 32 and 33 are adhesively fixed to the rotor hub 11 and the central shaft portion 14 as described above, the third step shown in FIG. 3 is performed. In the third step, the tip of the central shaft portion 14 is moved from below the central hole 24 of the rotor hub 11 to the inner ring 32 of the first ball bearing 32.
The outer ring 33a of the second ball bearing 33 is bonded and fixed to the inner peripheral surface of the central hole 24 while being inserted into the inside a and bonded and fixed.

At this time, the central shaft portion 14 is positioned such that the upper surface of the outer ring 33a of the second ball bearing 33 contacts the lower surface of the annular protrusion 25, and the ball bearings 32 and 33 are bonded in this state. By fixing, the rotor hub 11 is rotatably attached to the central shaft portion 14. Such ball bearings 32,3
When the adhesive fixing of No. 3 is performed, before the adhesives respectively interposed between the inner ring 32b and the central shaft portion 14 and between the outer ring 33a and the inner peripheral surface of the central hole 24 are hardened, arrows in FIG. As shown in, when a load W is applied to the inner ring 32b of the first ball bearing 32, this load pulls the inner ring 32b of the first ball bearing 32 downward, and
The outer ring 33a of the second ball bearing 33 has an annular protrusion 2
Since it is pressed by 5, each ball bearing 3
It is possible to fix the ball bearings 32 and 33 by adhesion while preload is introduced, and thus it is possible to avoid inconveniences such as looseness of the ball bearings 32 and 33.

As described above, the central shaft portion 14 has the first and second
Rotor hub 11 via two ball bearings 32, 33
Then, in this state, the annular overhanging portion 28, which is the mounting surface of the magnetic disk, is cut. In the cutting process at this time, since the central shaft portion 14 is not yet fixed to the bracket 13 and the central shaft portion 14 is provided with at least this fixed portion, it is a fixed portion of the central shaft portion 14. The lower end side can be supported.

The cutting process at this time is described, for example, in Japanese Unexamined Patent Publication No.
It can be performed by the method disclosed in Japanese Patent No. 8151. On the other hand, the assembly of the stationary member 10 except the fixing of the central shaft portion 14 proceeds at the same time as the steps shown in FIGS. 1 to 3, and the stator coil 22 is attached to the step portion 18 of the bracket 13 as shown in FIG. The wound stator core 21 is fixed,
The ends of the coil 22 are connected to the flexible printed board 34.

Then, the central shaft portion 14 in the state shown in FIG.
By press-fitting and fixing the lower end of the above into the hole 17 of the bracket 13 shown in FIG. 4, the motor shown in FIG. 5 is obtained, and the assembly is completed. In this case, please note that the second
A space is provided between the outer ring 33a of the ball bearing 33 so that the outer ring 33a of the ball bearing 33 does not come into contact with the annular convex portion 19 of the bracket 13. By providing such a space, the outer ring 33a of the second ball bearing 33 is provided. It is possible to prevent the applied preload from coming off.

According to the spindle motor assembling method performed in the above steps, the first and second ball bearings 3 are fixed before the central shaft portion 14 is fixed to the bracket 13.
Since it includes a step of attaching the rotor hub 11 to the rotor hub 11 through 2, 33, the rotor hub 11 supports the fixed portion of the central shaft portion 14 to the bracket 13 in a rotatable state, and the rotor hub 11 can be mounted on the magnetic disk mounting portion of the rotor hub 11. Ring-shaped overhang 2
8 can be cut, the processing accuracy of the mounting portion of the magnetic disk can be easily secured, and the production efficiency of the motor is improved.

The outer ring 32a of the first ball bearing 32 is adhered and fixed to the rotor hub 11, and the central shaft portion 1
4, the inner ring 33b of the second ball bearing 33 is fixedly bonded, and the central shaft portion 14 is fixed to the inner ring 3 of the first ball bearing 32.
When a load is applied to the inner ring 32b of the first ball bearing 32 and the outer ring of the second ball bearing 33 is adhesively fixed in a state of being inserted in 2b, a preload is introduced to each ball bearing 32, 33. This preload can prevent the bearing from rattling.

FIG. 6 shows another embodiment of the spindle motor assembling method according to the present invention. In the assembly method shown in the figure, first, the outer rings 32a and 33a of the first and second ball bearings 32 and 33 are adhesively fixed to the inner peripheral surface of the center hole 24 of the rotor hub 11. In this case, the first ball bearing 32 is inserted from the upper side of the center hole 24, the second ball bearing 33 is inserted from the lower side of the center hole 24, and the end portions of the outer rings 32a and 33a are annular protruding portions 25. Position and fix it so that it abuts on the end surface of.

Then, each ball bearing 32,
The central shaft portion 14 is inserted into the inner rings 32b and 33b of 33 and fixed by adhesion. A load is applied to the inner ring 32b of the first ball bearing 32 also during this adhesive fixing. When the adhesive fixing of the central shaft portion 14 is completed, the annular overhanging portion 2 of the rotor hub 11 is
8 is performed, after which the central shaft portion 14 is fixed to the hole portion 17 of the bracket 13 shown in FIG. 4, and the assembly of the motor is completed.

Even if the spindle motor is assembled in such a process, the same effect as that of the above embodiment can be obtained.

[0030]

As described above in detail in the embodiments,
According to the spindle motor assembling method of the present invention,
The processing accuracy of the mounting portion of the magnetic disk can be easily ensured, and the motor production efficiency is improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a first step showing an embodiment of a spindle motor assembling method according to the present invention.

FIG. 2 is a sectional view of a second step showing an embodiment of the spindle motor assembling method according to the present invention.

FIG. 3 is a sectional view of a third step showing an embodiment of the spindle motor assembling method according to the present invention.

FIG. 4 is a sectional view of a fourth step showing an embodiment of the spindle motor assembling method according to the invention.

FIG. 5 is a sectional view of a spindle motor assembling method according to the present invention in an assembled state.

FIG. 6 is a sectional view showing another embodiment of the spindle motor assembling method according to the present invention.

[Explanation of symbols]

 10 stationary member 11 rotor hub (rotating member) 12 bearing portion 13 bracket 14 center shaft portion 21 stator core 22 stator coil 30 rotor yoke 31 rotor magnet 32 first ball bearing 32a outer ring 32b inner ring 33 second ball bearing 33a outer ring 33b inner ring

Claims (2)

[Claims] 1. A stationary member to which a stator coil that generates a current magnetic field in an excited state is mounted, a rotating member to which a rotor magnet that obtains a rotational force by electromagnetic interaction with the current magnetic field of the stator coil is mounted, and the stationary member. In a method of assembling a spindle motor having a bearing portion provided between the rotary member and the rotating member, the stationary member has a bracket to which the stator coil is attached, and a central shaft portion fixed to the bracket, A method of assembling a spindle motor, comprising the step of attaching the central shaft portion to the rotating member via the bearing member before fixing the central shaft portion to the bracket. 2. The bearing portion is composed of a pair of first and second ball bearings arranged vertically along the axial direction of the central shaft portion, and an outer ring of the first ball bearing serves as the rotating member. After fixing and fixing the inner ring of the second ball bearing to the central shaft portion, the inner ring of the first ball bearing is adhesively fixed to the central shaft portion, and the outer ring of the second ball bearing is fixed to the rotating member. 2. Adhesive fixing.
A method for assembling the described spindle motor.