JPH0510339A - Fitting structure for rotor to fixed member - Google Patents

Abstract

PURPOSE:To correctly fit a rotor to a fixed member without being affected by the tolerance of the thickness size of a bearing by providing projections brought into contact with end sections on the same side of the inner ring and the outer ring of the bearing on the fixed member and the rotor respectively. CONSTITUTION:A spindle motor 30 is constituted of a fixed frame 31 wholly supported on a magnetic disk device C and a rotor 34 fitted with a disk D and rotated by a pair of bearings 32, 33 with respect to the fixed frame 31. Projections 45, 46 brought into contact with end sections 43, 44 on the same side of the outer ring 41 and the inner ring 42 of one bearing 32 are formed on the fixed frame 31 and the rotor 34 respectively. The interval L between the fitting reference face 47 of the fixed frame 31 and the disk fitting face 48 of the rotor 34 is set when the end section 43 of the outer ring 41 is pressed to the projection 45 and the end section 44 of the inner ring 42 is pressed to the projection 46. The size precision of the interval L is increased without being affected by the tolerance of the thickness size B of the bearing 32, and the interval with a reading head can be set with good precision.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for mounting a rotating body that rotates on a fixed member via a bearing, mainly to a structure for mounting a rotor on a fixed frame of a spindle motor.

[0002]

2. Description of the Related Art Conventionally, there is a motor generally called a spindle motor which is mainly used for rotating a disk (magnetic disk, optical disk) or the like. As shown in FIG. 3, this spindle motor includes a fixed frame (fixing member) 11 for supporting the entire spindle motor 10 on a magnetic disk device or an optical disk device A, and a fixed frame 11 by a bearing 12 and 20 on which a disk D is mounted. It has a rotor (rotating body) 13 that rotates with respect to. The distance L between the disk mounting surface 19 of the rotor 13 and the mounting reference surface 18 of the fixed frame 11 is set by sandwiching the bearing 12 between the protrusion 15 of the rotor 13 and the protrusion 14 of the fixed frame 11. Projection 1 of rotor 13
5 presses the upper end of the inner ring 17, and the protrusion 14 of the fixed frame 11 receives the lower end of the outer ring 16 of the bearing 12.

[0003]

However, the above-mentioned distance L set by such a structure is set in the bearing 12
It is subject to the tolerance of the thickness dimension (B). Therefore, the distance between the disk D mounted on the rotor 13 and the read / write head (not shown) facing the disk D varies for each spindle motor, and the read / write operation of the disk device becomes inaccurate. There is a problem.

By the way, to explain this problem with specific numerical values, the allowable tolerance of the thickness dimension (B) of the bearing due to the tolerance is about 0.04 mm (plus or minus 2).
mm), and the tolerance of the interval L is about 0.06 mm (plus or minus 3 mm). Therefore, the actual tolerance of the distance L is about 0.02 mm, which is the difference between both tolerances.
It is narrowed to (plus or minus 1 mm), and unless the processing accuracy and the assembly accuracy of the fixed frame and the rotor are within this range, the read / write operation of the disk device becomes inaccurate.

Therefore, as a method of coping with such a problem, there is a method of setting the above-mentioned interval L to be longer and grinding the disk mounting surface 19 after the spindle motor is assembled so that the disk mounting surface 19 is within a predetermined tolerance. However, in this case, there is a problem that it takes time to manufacture the spindle motor.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a protrusion that abuts on the same side end of an inner ring and an outer ring of a bearing that rotatably supports a rotating body on a fixed member is provided on the fixed member and the rotating body, respectively. The mounting structure provided solves the above-mentioned problems.

[0007]

Since the ends of the inner ring and the outer ring of the bearing on the same side contact the protrusion of the fixed member and the protrusion of the rotary member, the rotary member can be attached to the fixed member without sandwiching the bearing. Therefore, the rotating body is attached to the fixed member without being affected by the tolerance of the width dimension of the bearing.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the spindle motor includes a fixed frame (fixing member) 31 for supporting the entire spindle motor 30 on the magnetic disk device C, and a fixed frame 3 with a pair of bearings 32, 33 on which a disk D is mounted.
And a rotor (rotating body) 34 that rotates with respect to 1. Rotation of the rotor 34 is performed by the armature 35 provided on the fixed frame 31 and the magnet 36 provided on the inner circumference of the rotor 34.
It is done by magnetic action with. A pair of bearings 3
2, 33 are separated from each other by a spacer 37,
The bearing holding hole 39 of the fixed frame 31 and the rotor 3
It is press-fitted into the shaft portion 40 of No. 4.

The fixed frame 31 and the rotor 34 are respectively formed with projections 45 and 46 which come into contact with the same side ends 43 and 44 of the outer ring 41 and the inner ring 42 of one bearing 32, respectively. The distance L between the mounting reference surface 47 of the fixed frame 31 and the disk mounting surface 48 of the rotor 34 is determined by the bearing 3
It is set by pressing the end 43 of the second outer ring 41 against the protrusion 45 and the end 44 of the inner ring 42 against the protrusion 46. Therefore, this interval L is set regardless of the tolerance of the width dimension of the bearing 32.

Therefore, this distance L is determined by the bearing 3
Since it is not affected by the tolerance of the thickness dimension (B) of 2, the dimensional accuracy of the interval L can be improved. Further, if the dimensional accuracy of the distance L can be increased, the distance between the disk D mounted on the rotor 34 and the read / write head (not shown) facing the disk D can be set accurately. Become.

Further, since the dimension of the distance L is not influenced by the tolerance of the thickness dimension (B) of the bearing 32, the tolerance of the dimension of the distance L is not narrowed as in the conventional case. By the way, to explain this with specific numerical values, as described above, the tolerance of the bearing thickness dimension (B) is usually about 0.04 mm, and the tolerance of the interval L is about 0.06 mm. Is. Based on this number, the actual tolerance of the conventional spacing L is narrowed to about 0.02 mm, which is the difference between both tolerances.
In the case of the present invention, since the bearing is not affected by the tolerance, the allowable tolerance of the interval L is the tolerance (about 0.06 mm).
There is no such thing as becoming itself. Therefore, the processing and assembly of the fixed frame and the rotor are facilitated.

Further, it is possible to omit the conventional additional process which has been conventionally performed such that the interval L is made longer and the disc mounting surface is ground to be within a predetermined allowable tolerance after the spindle motor is assembled. Further, the protrusion 14 which is conventionally required is provided with the bearing holding hole 39 of the fixed frame 31.
It is not necessary to form it in the middle of
The bearing holding hole 39 can be easily processed by the turning tool 50 of the lathe. Also, the bearing holding hole 39
From one side, the bearing 32, the spacer 37, and the bearing 33 can be assembled in order, and the assembly of the spindle motor can be automated.

[0013]

EFFECTS OF THE INVENTION According to the mounting structure of the rotating member to the fixing member of the present invention, the following effects can be obtained. (1) Since the rotating body can be incorporated into the fixed member without interposing the bearing, it is not affected by the tolerance of the bearing thickness dimension, and the distance between the rotating body and the fixed member can be set accurately. At the same time, the positions of other members mounted on the rotating body can be accurately positioned. (2) After assembling the rotating body to the fixed member with a longer interval, both are assembled, then the rotating body is ground and the additional process of keeping the interval within the specified tolerance is not required, and the assembly is easy. become. (3) It is no longer necessary to form a protrusion that has been conventionally required in the middle of the bearing holding hole of the fixed frame, and for example, it is possible to easily perform hole processing using a turning tool of a lathe. (4) Since there is no protrusion in the middle of the bearing holding hole, a plurality of bearings can be assembled from one of the bearing holding holes, and the assembly can be automated.

[Brief description of drawings]

FIG. 1 is a front sectional view of a spindle motor having a mounting structure of the present invention.

FIG. 2 is a state diagram when a bearing holding hole is processed by a turning tool of a lathe.

FIG. 3 is a front sectional view of a spindle motor having a conventional mounting structure.

[Explanation of symbols]

31 Fixed frame (fixing member) 32 bearings 34 rotor (rotating body) 41 outer ring 42 Inner ring 43,44 end 45,46 Projection

Claims (2)

[Claims] 1. A fixing member and a rotating body are respectively provided with protrusions that come into contact with end portions on the same side of an inner ring and an outer ring of a bearing that rotatably supports the rotating member on the fixing member. Mounting structure of the rotating body to the fixed member. 2. The mounting structure according to claim 1, wherein the fixing member is a fixing frame of a spindle motor, and the rotating body is a rotor of the spindle motor.