JP2003307215A - Bearing unit and thin motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing unit and a thin motor for journaling the same shaft by a pair of bearings, and having a small shaft directional dimension. <P>SOLUTION: In this bearing unit 1, the outer diameter of an outer ring 7 of the second bearing 3 positioned inside the first bearing 2 is constituted smaller than the inner diameter of an inner ring 6 of the first bearing 2. The inner ring 6 of the first bearing 2 and the inner ring 8 of the second bearing 3 are integrally held by an inner ring holder 11, and an outer ring 5 of the first bearing 2 and the outer ring 7 of the second bearing 3 are integrally held by an outer ring holder 10. An engaging part between the outer ring holder 10 and the outer ring 5 is put in a state of being mutually relatively movable in the shaft direction. A disk spring 9 is interposed between the outer ring holder 10 and outer ring 5, and the disc spring 9 is installed so as to apply a constant-pressure preload in the shaft direction of the first and second bearings 2 and 3. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing unit and a thin motor, and more particularly to a thin bearing unit applied to office automation equipment, audio equipment, industrial equipment, robots and the like, and a thin motor using the bearing unit.

[0002]

2. Description of the Related Art FIG. 8 is a longitudinal sectional view and an enlarged view of a main part of a conventional cylindrical motor shown as an example of using a bearing. As shown in FIG. 8A, the motor 200 includes a coil iron core 202 fixed in a cylindrical case 210 and a coil 201.
And a rotor 206 in which a magnet 205 is integrated with a rotating shaft 204. The rotary shaft 204 of the rotor 206 is axially supported by the cylindrical case 210 by a pair of bearings 207 and 209 arranged at two axial positions with the magnet 205 interposed therebetween.
The shake associated with rotation of No. 4 is suppressed.

Further, as shown in FIG. 8B, a preload is applied in the axial direction of the bearings 207 and 209 between the outer ring 207a of the bearing 207 fixed to the rotary shaft 204 and the cylindrical case 210. A disc spring 208, which is a spring member for performing the operation, is interposed.

FIG. 9 is a vertical sectional view showing an example of a conventional bearing unit. As shown in FIG. 9, the bearing unit 300 includes a cylindrical housing 302 and a housing 302.
It comprises a pair of bearings 303, 305 arranged at two locations in the axial direction at a predetermined interval, and a rotary shaft 301 pivotally supported by these bearings 303, 305.

The rotary shaft 301 has the bearings 303,
Race groove 3 that becomes the orbit of ball 306, which is the rolling element of 305
01a is provided and is a type of bearing that does not use an inner ring. A disc spring 307, which is a spring member for applying a preload to the bearings 303 and 305 in the axial direction, is interposed between the outer ring 303a of the bearing 303 and the housing 302.

[0006]

However, in the bearing unit 300 and the motor 200 as described above, a pair of bearings are arranged at two positions in the axial direction at a predetermined interval. Therefore, there is a problem that the bearing unit 300 and the motor 200 are large in size in the axial direction and are large in size.

Particularly, in the case of the motor 200, the stator 2
03 and the magnet 205 are improved and downsized, there is a problem that the width of the two bearings 207 and 209 becomes large in the axial direction, which hinders reduction in thickness. Therefore,
An object of the present invention is to solve the above problems, and to provide a bearing unit and a thin motor that can support the same shaft with a pair of bearings and have a small axial dimension.

[0008]

SUMMARY OF THE INVENTION The above object of the present invention is a bearing unit for supporting the same shaft by first and second bearings, the second unit being located inside the first bearing. The outer diameter of the outer ring of the bearing is smaller than the inner diameter of the inner ring of the first bearing, and the inner ring of the first bearing and the inner ring of the second bearing are integrally held by an inner ring holder. An outer ring of the first bearing and an outer ring of the second bearing are integrally held by an outer ring holder, and between the inner ring holder and the inner ring of the first bearing or the second bearing, or At least one engaging portion between the outer ring holder and the outer ring of the first bearing or the second bearing,
This is achieved by a bearing unit which is assembled so as to apply a preload in the axial direction of the first and second bearings.

According to the bearing unit having the above structure, since the second bearing is located inside the first bearing, the first and second bearings are configured to overlap each other in the radial plane. Therefore, the axial dimension of the bearing unit can be made smaller than in the case where the pair of bearings are arranged in series in the axial direction. Moreover, since the first and second bearings are assembled so as to apply a preload in the axial direction, the radial and axial positioning is accurately performed, and the shake due to the rotation of the shaft can be suppressed. .

It is preferable that the engaging portions are axially movable relative to each other and a spring member is interposed to apply a constant pressure preload to the first and second bearings in the axial direction. It is assembled as follows. Also, preferably, the engaging portion is fixed so as to apply a fixed position preload in the axial direction of the first and second bearings. Further, preferably 25% or more of the width of the second bearing falls within the range of the width of the first bearing.

Further, the above object of the present invention is achieved by a thin motor characterized in that the stator and the rotor are relatively rotatable by the bearing unit having the above configuration.

According to the thin motor having the above structure, the axial dimension of the bearing unit that allows the stator and the rotor to rotate relative to each other can be reduced, and the axial dimension of the motor can be shortened.
Further, when the stator and the rotor are improved and downsized, the axial dimension of the bearing unit does not prevent the motor from being thinned.

The stator and the rotor are preferably arranged between the innermost peripheral surface of the inner ring holder of the bearing and the outermost peripheral surface of the outer ring holder of the bearing. In this case, since the motor portion including the stator and the rotor is housed within the innermost peripheral surface of the inner ring holder and the outermost peripheral surface of the outer ring holder, the radial dimension can be reduced and the axial dimension can be shortened.

Further, preferably, the stator and the rotor are arranged between the inner ring inner peripheral surface of the first bearing and the outer ring outer peripheral surface of the second bearing. In this case, since the motor portion including the stator and the rotor falls within the width range of the first and second bearings configured to overlap each other in the radial plane, the axial dimension of the motor can be further shortened.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a bearing unit and a thin motor according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a vertical sectional view of a bearing unit according to the first embodiment of the present invention. In the bearing unit 1 of the first embodiment, a shaft 13 is supported by first and second bearings 2 and 3 having the same bearing width, which are arranged so as to overlap each other in the radial direction.

The outer diameter of the outer ring 7 of the second bearing 3 located inside the first bearing 2 is smaller than the inner diameter of the inner ring 6 of the first bearing 2. And the first
The inner ring 6 of the bearing 2 and the inner ring 8 of the second bearing 3 are integrally held by an inner ring holder 11, and the first ring
The outer ring 5 of the bearing 2 and the outer ring 7 of the second bearing 3 are integrally held by an outer ring holder 10.

The inner ring holder 11 has a small-diameter cylindrical inner engagement portion 11a and an large-diameter cylindrical outer engagement portion 11 extending in the axial direction.
b is an annular member having a U-shaped cross section, the inner engagement portion 11a is fixed to the inner peripheral surface of the inner ring 8 of the second bearing 3, and the outer engagement portion 11b is the first engagement member. It is fixed to the inner peripheral surface of the inner ring 6 of the bearing 2.

The outer ring holder 10 has a small-diameter tubular inner engagement portion 10a and a large-diameter tubular outer engagement portion 10 extending in the axial direction.
b is an annular member having a U-shaped cross section, the inner engagement portion 10a is fixed to the outer peripheral surface of the outer ring 7 of the second bearing 3, and the outer engagement portion 10b is the first engagement member. The outer peripheral surface of the outer ring 5 of the bearing 2 is closely fitted to the outer peripheral surface of the bearing 2 so as to be relatively movable.

The outer ring holder 10 and the outer ring 5
The engaging portions between the outer ring holder 10 and the outer ring 5 are axially movable relative to each other, and a disc spring 9 as a spring member is interposed between the outer ring holder 10 and the outer ring 5. The disc spring 9 is assembled so as to apply a constant pressure preload in the axial direction of the first and second bearings 2 and 3.

The other engaging portions between the outer ring holder 10 and the outer ring 7 and between the inner ring holder 11 and the inner rings 6 and 8 are fixed by adhesion or press fitting. Therefore, when the bearing unit 1 is used, the shaft 13 is used by being fixed to the inner peripheral surface of the inner engagement portion 11a of the inner ring holder 11.

That is, according to the bearing unit 1 of the first embodiment, since the second bearing 3 is located inside the first bearing 2, the first and second bearings 2 and 3 are arranged in the radial direction. It is configured to overlap in the plane. Therefore, compared with the case where a pair of bearings are arranged in series in the axial direction, the bearing unit 1
The axial dimension of can be made slightly smaller than the width of one bearing.

The first and second bearings 2 and 3 are
Since the disc spring 9 is assembled so as to apply a constant pressure preload in the axial direction, the radial and axial positioning is accurately performed. Therefore, although the bearing unit 1 supports the shaft 13 at one position in the axial direction, it is possible to suppress the shake due to the rotation of the shaft 13. The shaft 13 may or may not be provided.

FIG. 2 is a vertical sectional view of a bearing unit according to the second embodiment of the present invention. In the bearing unit 21 of the second embodiment, the shaft 13 is supported by first and second bearings 22 and 23 having different bearing widths, which are arranged so as to overlap each other in the radial direction. The second member located inside the first bearing 22.
The outer diameter of the outer ring 27 of the bearing 23 is smaller than the inner diameter of the inner ring 26 of the first bearing 22. The inner ring 26 of the first bearing 22 and the inner ring 28 of the second bearing 23 are integrally held by the inner ring holder 31, and the outer ring 25 of the first bearing 22 and the second bearing are held together. The outer ring 27 of 23 is integrally held by the outer ring holder 30.

The inner ring holder 31 has a small-diameter cylindrical inner engagement portion 31a and an large-diameter cylindrical outer engagement portion 31 extending in the axial direction.
b is an annular member having a U-shaped cross section, the inner engagement portion 31a is fixed to the inner peripheral surface of the inner ring 28 of the second bearing 23, and the outer engagement portion 31b is the first engagement member. Bearing 2
It is fixed to the inner peripheral surface of the second inner ring 26.

The outer ring holder 30 has a small-diameter tubular inner engagement portion 30a and a large-diameter tubular outer engagement portion 30 extending in the axial direction.
b is an annular member having a U-shaped cross section, the inner engagement portion 30a is fixed to the outer peripheral surface of the outer ring 27 of the second bearing 23, and the outer engagement portion 30b is the first engagement member. Bearing 2
The outer peripheral surface of the second outer ring 25 is closely fitted to allow a relative movement.

Then, the outer ring holder 30 and the outer ring 2
The engaging portion between the outer ring holder 5 and the outer ring 25 is axially movable relative to each other, and a disc spring 29, which is a spring member, is interposed between the outer ring holder 30 and the outer ring 25. , The disc spring 29 has the first and second bearings 22, 23.
It is assembled so as to apply a constant pressure preload in the axial direction of.

The other engaging portions between the outer ring holder 30 and the outer ring 27 and between the inner ring holder 31 and the inner rings 26, 28 are fixed by adhesion or press fitting.
Therefore, when the bearing unit 21 is used, the shaft 13 is used by being fixed to the inner peripheral surface of the inner engagement portion 31a of the inner ring holder 31. That is, also with the bearing unit 21 of the second embodiment, it is possible to obtain the same effect as that of the bearing unit 1 of the first embodiment. The bearing width of the second bearing 23 may be widened.

FIG. 3 is a vertical sectional view of a bearing unit according to the third embodiment of the present invention. The bearing unit 41 of the third embodiment has the same bearing width arranged in the radial direction so that 25% of the width of the second bearing 43 falls within the range of the width of the first bearing 42. 1st and 2nd bearing 42,43
Thus, the shaft 13 is pivotally supported.

The outer diameter of the outer ring 47 of the second bearing 43 located inside the first bearing 42 is equal to that of the first bearing 4
The inner diameter of the second inner ring 46 is smaller than that of the second inner ring 46. Then, the inner ring 46 of the first bearing 42 and the second bearing 4
The inner ring 48 of No. 3 is integrally held by the inner ring holder 51, and the outer ring 45 of the first bearing 42 and the second ring
The outer ring 47 of the bearing 43 is integrally held by the outer ring holder 50.

The inner ring holder 51 has a small-diameter cylindrical inner engagement portion 51a extending in the axial direction and a large-diameter cylindrical outer engagement portion 51.
b is an annular member having a U-shaped cross section, the inner engagement portion 51a is fixed to an inner peripheral surface of the inner ring 48 of the second bearing 43, and the outer engagement portion 51b is the first engagement member. Bearing 4
It is fixed to the inner peripheral surface of the second inner ring 46.

The outer ring holder 50 has a small-diameter tubular inner engagement portion 50a extending in the axial direction and a large-diameter tubular outer engagement portion 50.
b is an annular member having a U-shaped cross section, the inner engagement portion 50a is fixed to the outer peripheral surface of the outer ring 47 of the second bearing 43, and the outer engagement portion 50b is the first engagement member. Bearing 4
The outer peripheral surface of the second outer ring 45 is closely fitted to allow a relative movement.

Then, the outer ring holder 50 and the outer ring 4
The engaging portion between the outer ring holder 50 and the outer ring 45 is movable relative to each other in the axial direction, and a disc spring 49, which is a spring member, is interposed between the outer ring holder 50 and the outer ring 45. , The disc spring 49 has the first and second bearings 42, 43.
It is assembled so as to apply a constant pressure preload in the axial direction of.

Other engaging portions between the outer ring holder 50 and the outer ring 47 and between the inner ring holder 51 and the inner rings 46 and 48 are fixed by adhesion or press fitting.
Therefore, when the bearing unit 41 is used, the shaft 13 is used by being fixed to the inner peripheral surface of the inner engagement portion 51a of the inner ring holder 51. That is, the bearing unit 41 of the third embodiment can also obtain the same effects as the bearing unit 1 of the first embodiment.

Further, the bearing unit 41 of the third embodiment.
In the above, the bearing unit 1 of the first embodiment is arranged by overlapping 25% of the width of the second bearing 43 in the radial direction so as to be within the range of the width of the first bearing 42.
The dimension in the axial direction is slightly longer than that of the inner ring engaging portion 51a of the inner ring holder 51 that supports the shaft 13.
The axial width can be increased to increase the support rigidity, and the deflection of the shaft 13 can be reduced. If it is desired to further increase the supporting rigidity, the overlap may be 25% or less, but the axial dimension is lengthened by that amount, so it may be determined as necessary.

In each of the above embodiments, the deep groove ball bearing was used as the bearing, but the present invention is not limited to this, and any tapered roller bearing or angular contact bearing can be used as long as it can apply a preload in the axial direction. Various bearings can be used, such as ball bearings. Further, in each of the above-described embodiments, the engagement portion between the outer engagement portion of the outer race holder and the outer race of the first bearing is in a state of being relatively movable in the axial direction, and the spring member is interposed. The first and second bearings are mounted so as to apply a constant pressure preload to the axial direction of the first and second bearings, but the spring member is interposed so as to be relatively movable in the axial direction relative to each other. Is not limited to this, and at least one between the inner ring holder and the inner ring of the first bearing or the second bearing, or between the outer ring holder and the outer ring of the first bearing or the second bearing. It suffices if it is a single engaging portion. The spring member is not limited to the disc spring, and may be a wave washer, a coil spring, or the like.

Further, any one of the above engaging portions is also fixed, and all the engaging portions are fixed, so that a fixed position preload is applied in the axial direction of the first and second bearings. You can also Further, each of the above bearing units can be used either for inner ring rotation or outer ring rotation. Further, the shaft 13 may be omitted.

FIG. 4 is a vertical sectional view of a thin motor according to a fourth embodiment of the present invention. Thin motor 6 of the fourth embodiment
As shown in FIG. 4, the bearing unit 61 allows the stator 75 and the rotor 77 to rotate relative to each other. The bearing unit 61 has substantially the same configuration as the bearing unit 1 of the first embodiment, and includes first and second bearings 62 and 63 having the same bearing width arranged in the radial direction so as to overlap each other. The shaft 13 is pivotally supported.

The outer diameter of the outer ring 67 of the second bearing 63 located inside the first bearing 62 is equal to that of the first bearing 6.
The inner ring 66 of the first bearing 62 and the inner ring 6 of the second bearing 63 are smaller than the inner diameter of the second inner ring 66.
8 are integrally held by the inner ring holder 71, and the outer ring 65 of the first bearing 62 and the second bearing 6 are
The outer ring 67 of No. 3 is integrally held by the outer ring holder 70.

The inner ring holder 71 has a small-diameter tubular inner engagement portion 71a and a large-diameter tubular outer engagement portion 71 extending in the axial direction.
b, the inner engagement portion 71a is fixed to the inner peripheral surface of the inner ring 68 of the second bearing 63, and the outer engagement portion 71b is the inner periphery of the inner ring 66 of the first bearing 62. It is fixed to the surface. Further, on the outer peripheral portion of the inner ring holder 71,
The coil iron core 73 around which the coil 74 is wound is fixed, and constitutes the stator 75.

The outer ring holder 70 has a small-diameter cylindrical inner engagement portion 70a and a large-diameter cylindrical outer engagement portion 70 extending in the axial direction.
b, the inner engagement portion 70a is fixed to the outer peripheral surface of the outer ring 67 of the second bearing 63, and the outer engagement portion 70b is attached to the outer peripheral surface of the outer ring 65 of the first bearing 62. It is a clearance fit and is in a state of being capable of relative movement.

Then, the outer ring holder 70 and the outer ring 6
The engaging portion between the outer ring holder 70 and the outer ring 65 is axially movable relative to each other, and a disc spring 69, which is a spring member, is interposed between the outer ring holder 70 and the outer ring 65. , The disc spring 69 has the first and second bearings 62, 63.
It is assembled so as to apply a constant pressure preload in the axial direction of. Further, a magnet 76 is integrated with the inner peripheral surface of the extension portion of the outer ring holder 70, which is formed by extending the outer engagement portion 70b in the axial direction, and constitutes a rotor 77.

That is, according to the thin motor 60 of the fourth embodiment, the axial dimension of the bearing unit 61, which allows the stator 75 and the rotor 77 to rotate relative to each other, can be reduced to shorten the axial dimension of the motor. Further, even when the stator 75 and the rotor 77 are improved and further downsized, the axial dimension of the bearing unit 61 does not prevent the motor from being made thinner. The coil 74 and the coil iron core 73 are attached to the outer ring holder 7
The magnet 76 may be attached to the inner peripheral surface of the inner ring holder 71 and the magnet 76 may be attached to the outer peripheral surface of the inner ring holder 71.

Further, since the first and second bearings 62, 63 of the bearing unit 61 are assembled by the disc spring 69 so as to apply a constant pressure preload in the axial direction, positioning in the radial direction and the axial direction is performed. Is done exactly.
Therefore, the bearing unit 61 can suppress the vibration of the stator 77 with respect to the rotation of the rotor 77, prevent the abnormal noise due to the axial vibration and resonance of the thin motor 60, and enable the smooth rotation. .
The shaft 13 may be omitted.

FIG. 5 is a vertical sectional view of a thin motor according to a fifth embodiment of the present invention. Thin motor 8 of the fifth embodiment
As shown in FIG. 5, the bearing unit 81 of No. 0 allows the stator 95 and the rotor 99 to rotate relative to each other. The bearing unit 81 has substantially the same structure as the bearing unit 21 of the second embodiment, and the first and second bearing units having different bearing widths are arranged in the radial direction so as to overlap each other.
A shaft 98 is supported by the bearings 82 and 83 of.

The outer diameter of the outer ring 87 of the second bearing 83 located inside the first bearing 82 is the same as that of the first bearing 8
The inner ring 86 of the first bearing 82 and the inner ring 8 of the second bearing 83 are smaller than the inner diameter of the second inner ring 86.
8 are integrally held by an inner ring holder 91, and the outer ring 85 of the first bearing 82 and the second bearing 8 are held together.
The outer ring 87 of No. 3 is integrally held by the outer ring holder 90.

The inner ring holder 91 has a small-diameter tubular inner engaging portion 91a and a large-diameter tubular outer engaging portion 91 extending in the axial direction.
b, the inner engagement portion 91a is fixed to the inner circumferential surface of the inner ring 88 of the second bearing 83, and the outer engagement portion 91b is the inner circumferential surface of the inner ring 86 of the first bearing 82. It is fixed to the surface.

The outer ring holder 90 has a small-diameter cylindrical inner engagement portion 90a extending in the axial direction and a large-diameter cylindrical outer engagement portion 90.
b, the inner engagement portion 90a is fixed to the outer peripheral surface of the outer ring 87 of the second bearing 83, and the outer engagement portion 90b is attached to the outer peripheral surface of the outer ring 85 of the first bearing 82. It is a clearance fit and is in a state of being capable of relative movement.

Then, the outer ring holder 90 and the outer ring 8
The engaging portion between the outer ring holder 5 and the outer ring 85 is axially movable relative to each other, and a disc spring 89, which is a spring member, is interposed between the outer ring holder 90 and the outer ring 85. , The disc spring 89 has the first and second bearings 82, 83.
It is assembled so as to apply a constant pressure preload in the axial direction of.

Further, on the outer side surface (left side surface in the figure) of the outer ring holder 90, a yoke 92, an insulating material 93 and a coil 9 are provided.
4 are integrated with each other to form a stator 95. On the other hand, at the end of the shaft 98, a disk-shaped magnet yoke 97 and a magnet 96 facing the coil 94 are integrated to form a rotor 99.

That is, also with the thin motor 80 of the fifth embodiment, it is possible to obtain the same effects as those of the thin motor 60 of the fourth embodiment. Furthermore, in the thin motor 80 of the fifth embodiment, in addition to the thin flat opposed motor portion, the axial dimension of the bearing unit 81 that allows the stator 95 and the rotor 99 to rotate relative to each other is reduced, thereby reducing the motor. The axial dimension of can be further shortened. In each of Embodiments 4 and 5, the motor portion is housed between the outermost peripheral surface of the outer ring holder and the innermost peripheral surface of the inner ring holder.
It is possible to reduce the axial dimension as well as the radial dimension.

FIG. 6 is a vertical sectional view of a thin motor according to a sixth embodiment of the present invention. Thin motor 1 of the sixth embodiment
00 indicates that the stator 115 and the rotor 117 are the first bearing 1 in the bearing unit 101.
No. 02 inner ring 106 and the outer ring 107 of the second bearing 103. The bearing unit 101 includes first and second bearings 102 and 103 having different bearing widths that are arranged in a radial direction so as to support a shaft 118.

The outer diameter of the outer ring 107 of the second bearing 103 located inside the first bearing 102 is smaller than the inner diameter of the inner ring 106 of the first bearing 102. The inner ring 106 of the bearing 102 and the inner ring 108 of the second bearing 103 are integrally held by an inner ring holder 111, and the outer ring 1 of the first bearing 102 is also held.
05 and the outer ring 107 of the second bearing 103 are integrally held by an outer ring holder 110.

The inner ring holder 111 is provided with an inner engagement portion 111a having a small diameter cylindrical shape and an outer engagement portion 111b having a large diameter cylindrical shape extending in the axial direction, and the inner engagement portion 111a has the second engagement portion. Fixed to the inner peripheral surface of the inner ring 108 of the bearing 103,
The outer engagement portion 111b is fixed to the inner peripheral surface of the inner ring 106 of the first bearing 102. Further, the coil 11 is formed on the inner peripheral surface of the outer engagement portion 111b of the inner ring holder 111.
The coil iron core 113 around which 4 is wound is fixed,
The stator 115 is configured.

The outer ring holder 110 is provided with an inner engagement portion 110a having a small-diameter tubular shape extending in the axial direction and an outer engagement portion 110b having a large-diameter tubular shape, and the inner engagement portion 110a has the second engagement portion. Fixed to the outer peripheral surface of the outer ring 107 of the bearing 103,
The outer engagement portion 110b is clearance-fitted to the outer peripheral surface of the outer ring 105 of the first bearing 102 so as to be relatively movable.

Then, the engaging portions between the outer ring holder 110 and the outer ring 105 are made to be relatively movable in the axial direction with each other, and a spring is provided between the outer ring holder 110 and the outer ring 105. A disc spring 109, which is a member, is interposed, and the disc spring 109 is assembled so as to apply a constant pressure preload in the axial direction of the first and second bearings 102 and 103. Further, a magnet 116 is integrated with the outer peripheral surface of the inner engagement portion 110a of the outer ring holder 110 to form a rotor 117. The outer ring holder 1
The coil iron core 113 around which the coil 114 is wound may be fixed to the outer peripheral surface of the inner engaging portion 110a of 10, and the magnet 116 may be fixed to the inner peripheral surface of the outer engaging portion 111b of the inner ring holder 111.

That is, the thin motor 100 of the sixth embodiment.
According to this, since the motor portion including the stator 115 and the rotor 117 is accommodated within the width range of the first and second bearings 102 and 103 configured to overlap each other in the radial plane, the axial dimension of the motor is determined. Can be further shortened. The shaft 113 may be omitted.

In the thin motors according to the fourth to sixth embodiments, the engagement portion between the outer engagement portion of the outer race holder and the outer race of the first bearing is axially movable relative to each other. In this state, a spring member is interposed and assembled so as to apply a constant pressure preload to the first and second bearings, but they are relatively movable in the axial direction. The engaging portion in which the spring member is interposed is not limited to this, and may be between the inner ring holder and the inner ring of the first bearing or the second bearing, or the outer ring holder and the first bearing or the second bearing.
It suffices if it is at least one engagement portion between the bearing and the outer ring. Further, it is also possible to fix any one of the above engaging portions and fix all the engaging portions so as to apply a fixed position preload in the axial direction of the first and second bearings. .

FIG. 7 is a vertical sectional view of a thin motor according to a seventh embodiment of the present invention. Thin motor 1 of the seventh embodiment
As shown in FIG. 7, the stator 20 and the rotor 137 are the same as those of the first bearing 1 in the bearing unit 121.
It is arranged between the inner ring 126 of 22 and the outer ring 127 of the second bearing 123. The bearing unit 121 includes first and second bearing units that have the same bearing width and are arranged in a radial direction.
A shaft 138 is axially supported by the bearings 122 and 123.

The outer diameter of the outer ring 127 of the second bearing 123 located inside the first bearing 122 is smaller than the inner diameter of the inner ring 126 of the first bearing 122. The inner ring 126 of the bearing 122 and the inner ring 128 of the second bearing 123 are integrally held by the inner ring holder 131, and the outer ring 1 of the first bearing 122 is also held.
25 and the outer ring 127 of the second bearing 123 are integrally held by an outer ring holder 130.

The inner ring holder 131 is provided with an inner engagement portion 131a having a small-diameter tubular shape and an outer engagement portion 131b having a large-diameter tubular shape extending in the axial direction, and the inner engagement portion 131a is the second engagement portion. Fixed to the inner peripheral surface of the inner ring 128 of the bearing 123,
The outer engagement portion 131b is fixed to the inner peripheral surface of the inner ring 126 of the first bearing 122. Further, a magnet 136 is integrated with the inner side surface (left side surface in the figure) of the inner ring holder 131 to form a rotor 137.

The outer ring holder 130 includes an inner engagement portion 130a having a small diameter tubular shape and an outer engagement portion 130b having a large diameter tubular shape extending in the axial direction, and the inner engagement portion 130a has the second engagement portion. Fixed to the outer peripheral surface of the outer ring 127 of the bearing 123,
The outer engagement portion 130b is fixed to the outer peripheral surface of the outer ring 125 of the first bearing 122.

That is, the inner ring holder 131 and the first bearing 12
All engagement parts between the inner ring 126, 128 of the second or second bearing 123 or between the outer ring holder 130 and the outer ring 125, 127 of the first bearing 122 or the second bearing 123 are fixed. By doing so, the first and second bearings are assembled so as to apply a fixed position preload in the axial direction. Further, a yoke 132, an insulating material 133, and a coil 134 are integrated with each other on an inner side surface (right side surface in the drawing) of the outer ring holder 130 to form a stator 135.

That is, the thin motor 120 of the seventh embodiment.
According to this, since the motor portion including the stator 135 and the rotor 137 is accommodated within the width range of the first and second bearings 122 and 123 configured to overlap in the radial plane, the axial dimension of the motor is determined. Can be further shortened.

Each of the thin motors according to the fourth to seventh embodiments can be used as either an outer ring rotating type or an inner ring rotating type by exchanging the fixed positions of the coil core around which the coil is wound and the magnet. It can be applied. The configurations of the bearing unit and the thin motor of the present invention are not limited to the configurations of the above-described embodiments, and it goes without saying that various configurations can be adopted based on the spirit of the present invention.

[0065]

As described above, according to the bearing unit of the present invention, since the second bearing is located inside the first bearing, these first and second bearings are in the radial plane. It is configured to overlap. Therefore, the axial dimension of the bearing unit can be made smaller than in the case where the pair of bearings are arranged in series in the axial direction. Also, these first and second
Since the bearing of (1) is assembled so as to apply a preload in the axial direction, the positioning in the radial direction and the axial direction is accurately performed, and the shake due to the rotation of the shaft can be suppressed.

Further, according to the thin motor of the present invention, the axial dimension of the motor can be shortened by reducing the axial dimension of the bearing unit that allows the stator and the rotor to rotate relative to each other. Also, when the stator and rotor are improved and downsized,
The axial dimension of the bearing unit does not prevent the motor from becoming thinner. Therefore, the same shaft can be supported by a pair of bearings, and a bearing unit and a thin motor having a small axial dimension can be provided.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a bearing unit according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of a bearing unit according to a second embodiment of the present invention.

FIG. 3 is a vertical sectional view of a bearing unit according to a third embodiment of the present invention.

FIG. 4 is a vertical sectional view of a bearing unit according to a fourth embodiment of the present invention.

FIG. 5 is a vertical sectional view of a bearing unit according to a fifth embodiment of the present invention.

FIG. 6 is a vertical sectional view of a bearing unit according to a sixth embodiment of the present invention.

FIG. 7 is a vertical sectional view of a bearing unit according to a seventh embodiment of the present invention.

FIG. 8A is a vertical sectional view of a conventional motor,
(B) is an enlarged view of part A in (a).

FIG. 9 is a vertical sectional view of a conventional bearing unit.

[Explanation of symbols]

1 Bearing unit 2 First bearing 3 Second bearing 5,7 outer ring 6,8 inner ring 9 Disc spring (spring member) 10 Outer ring holder 11 Inner ring holder 13 axes 60 thin motor 61 Bearing unit 62 first bearing 63 Second bearing 65,67 outer ring 66,68 Inner ring 69 Disc spring (spring member) 70 Outer ring holder 71 Inner ring holder 75 stator 77 rotor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H02K 5/16 H02K 5/16 Z 5/167 5/167 A 5/24 5/24 B 21/22 21 / 22 M F term (reference) 3J012 AB04 BB03 BB05 CB03 FB10 HB02 3J017 AA01 AA03 AA10 CA01 CA06 DA01 DB07 DB09 3J101 AA02 AA42 AA52 AA62 AA82 BA77 FA01 FA41 FA53 GA24 GA32 GA53 5H605 BB05 BB19 CC04 EB10 EB16 EB39 5H621 GA01 GA16 JK02 JK03 JK07 JK15 JK17

Claims (7)

[Claims] 1. A bearing unit for supporting the same shaft by first and second bearings, wherein an outer diameter of an outer ring of the second bearing located inside the first bearing is equal to that of the first bearing. The inner ring of the first bearing and the inner ring of the second bearing are integrally held by an inner ring holder, and the inner ring of the first bearing and the outer ring of the first bearing are smaller than the inner ring of the first bearing. The outer ring of the second bearing is integrally held by the outer ring holder, and is between the inner ring holder and the inner ring of the first bearing or the second bearing, or the outer ring holder and the first bearing or the first bearing. A bearing unit, wherein at least one engaging portion between the outer ring of the second bearing and the outer ring is assembled so as to apply a preload in the axial direction of the first and second bearings. . 2. The engaging portions are arranged to be relatively movable in the axial direction relative to each other, and a spring member is interposed so as to apply a constant pressure preload to the axial directions of the first and second bearings. The bearing unit according to claim 1, wherein the bearing unit is assembled. 3. The bearing unit according to claim 1, wherein the engagement portion is fixed so as to apply a fixed position preload in the axial direction of the first and second bearings. 4. The method according to claim 1, wherein 25% or more of the width of the second bearing is within the range of the width of the first bearing. Bearing unit. 5. A thin motor, wherein the stator and the rotor are rotatable relative to each other by the bearing unit according to any one of claims 1 to 4. 6. The thin structure according to claim 5, wherein the stator and the rotor are arranged between the innermost peripheral surface of the inner ring holder of the bearing and the outermost peripheral surface of the outer ring holder of the bearing. motor. 7. The stator and the rotor are arranged between an inner peripheral surface of an inner ring of the first bearing and an outer peripheral surface of an outer ring of the second bearing.
Thin motor described in.