JPH076700Y2 - Outer rotor type motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an outer rotor type motor for rotationally driving a magnetic disk or the like.

[Prior Art] An outer rotor type motor generally includes a housing, a rotating shaft that is rotatable relative to the housing, and an outer rotor fixed to one end of the rotating shaft. A magnet is arranged and a stator is attached to the housing. The rotary shaft is rotatably supported via two ball bearings arranged at intervals in the axial direction.

[Problems to be solved by the device]

However, in the conventional motor, when the number of magnetic disks or the like attached to the outer rotor increases, there is a problem that the outer rotor rotation support portion has insufficient rigidity and thus the outer rotor vibrates significantly (that is, shakes increase). .

In order to reduce this vibration, it may be possible to increase the capacity of the ball bearing, but if it is so large, it becomes difficult to reduce the cylindrical portion of the housing.

An object of the present invention is to solve the above problems existing in conventional motors, and to provide an outer rotor type motor which has less vibration and is compact as a whole.

[Means for Solving the Problems]

In the outer rotor type motor of the present invention, the housing is
It has a boss portion provided at the end of the cylindrical portion and a housing flange provided at the boss portion, and three bearings are interposed between the housing and the rotary shaft at intervals in the axial direction, The bearing on one end side and the intermediate bearing are arranged in the cylindrical portion, the bearing on the other end side is arranged on the boss portion, and the outer diameter thereof is larger than that of the bearing on the one side and the intermediate bearing, A first preload applying means for applying a first preload to both bearings is disposed between the bearings, and the intermediate bearing and the bearing on the other end side are arranged. And a second preload applying means for applying a second preload to both bearings.

[Action]

In the outer rotor type motor described above, since the rotating shaft is supported by three bearings, the rigidity of the supporting portion of the rotating shaft becomes large, and the outer diameter of the bearing arranged at the boss portion is larger than that of other bearings. Therefore, the rigidity is further increased. Further, since the outer diameters of the bearings on one end side and the intermediate bearings arranged in the cylindrical portion are smaller than the bearings on the other end side, the outer diameter of the cylindrical portion of the housing is small. The space between the outer peripheral surface and the inner peripheral surface of the outer rotor becomes large.
Further, a first preload applying means is provided between the bearing on one end side and the intermediate bearing, and a second preload applying means is provided between the bearing on the intermediate side and the bearing at the other end. Therefore, by setting these preloads, the preloads acting on these bearings are adjusted.

〔Example〕

Hereinafter, embodiments of an outer rotor type motor according to the present invention will be described with reference to the accompanying drawings.

In FIG. 1, the illustrated motor 1 includes a housing 4 and
It has an outer rotor 3 and a rotating shaft 5. The rotating shaft 5 is inserted through the housing 4, and three ball bearings 6a, 6b, 6c are arranged between them, and the rotating shaft 5 is rotatably supported by these three ball bearings 6a, 6b, 6c. Has been done.

As shown in FIG. 1, the housing 4 includes a cylindrical portion 9, a boss portion 14 provided at one end portion (lower end portion) of the cylindrical portion, and a housing flange provided at one end portion (lower end portion) of the boss portion 14. Have ten. The flange 14 protruding from the outer peripheral surface of the boss portion 14 in an outer flange shape is fixed to another member.

The outer rotor 3 has a cylindrical shape and has one end (upper end) thereof.
Is provided with an upper wall 7, and a rotor magnet 8 is attached to the inner surface thereof. The rotating shaft 5 is the housing 4
Of the outer rotor 3 and the central portion of the upper wall 7 of the outer rotor 3 is fixed to one end (upper end) 2 of the rotating shaft 5.

The three ball bearings 6a, 6b, 6c are composed of two types: a fixed bearing 6a on one end 2 side and preload bearings 6b, 6c on the intermediate side and the flange 10 side (the other end side). In the fixed bearing 6a, the inner ring 11a is fixed to the rotary shaft 5 and the outer ring 12a is fixed to the inner peripheral surface of the upper end of the cylindrical portion 9 of the housing 4.

The lower preload bearing 6c has a larger outer diameter than the fixed bearing 6a, and is disposed on the boss portion 14 of the housing 4. In this preload bearing 6c, an inner ring 11c is fixed to the rotary shaft 5, and an inner ring 12c is axially slidably mounted on the inner peripheral surface 13 of the cylindrical portion 9 of the housing 4.

The upper preload bearing 6b is the fixed bearing 6a.
The inner ring 11b is fixed to the rotating shaft 5 and the outer ring 1 has the same size as the preload bearing 6c.
2b is mounted on the inner peripheral surface 13 of the cylindrical portion 9 of the housing 4 so as to be slidable in the axial direction.

Reference numeral 15 is an intervening member formed of a ring body having a substantially L-shaped cross section, and the intervening member 15 is interposed between the preload bearings 6b and 6c.

Reference numeral 16a denotes an elastic means (which constitutes a first preload applying means) arranged between the fixed bearing 6a and the preload bearing 6b. In the embodiment, the elastic means 16a is constituted by a disc spring and is interposed between the step portion 17 provided on the inner peripheral surface of the circumferential portion 9 and the outer ring 12b of the upper preload bearing 6b, and from FIG. As will be readily understood, it acts to apply a first preload to the outer ring 12a of the fixed bearing 6a and the outer ring 12b of the upper preload bearing 6b.

Further, 16b is an elastic means (which constitutes a second preload applying means) arranged between the upper preload bearing 6b and the lower preload bearing 6c. In the embodiment, the elastic means 16
The b is also composed of a disc spring, is interposed between the lower preload bearing 6c and the interposition member 15, and acts so as to apply a second preload to the outer rings 12b, 12c of the preload bearings 6b, 6c.

Reference numerals 18 and 18 denote positioning snap rings attached to the rotary shaft 5, and the snap rings 18 and 18 act on the inner rings 11b and 11c of the preload bearings 6b and 6c, respectively.

Reference numeral 19 is a stator attached to the outer peripheral surface of the cylindrical portion 9 of the housing 4, and 20 is a magnetic seal attached to the inner peripheral surface of the upper end of the cylindrical portion 9 of the housing 4. This magnetic seal
The reference numeral 20 prevents the grease or the like of the fixed bearing 6a from spattering upward in the form of mist and intrusion of fine dust and dirt in the air into the housing 4 when the rotating shaft 5 rotates.

Further, when the outer rotor type motor 1 is used vertically as shown in the drawing, the preload is set so that both the preload bearings 6b and 6c are always pressed downward. That is, the first preload applied by the upper elastic means 16a-this is A-is greater than the second preload applied by the lower elastic means 16b-this is B-. (A> B).

With this setting, as can be easily understood from FIG. 1, the first preload A acts on the outer ring 12a of the fixed bearing 6a in the upward direction, and the outer ring 12 of the upper preload bearing 6b 12b.
The load (AB) of the difference between the first preload A and the second preload B acts on b in the downward direction, and the second preload B is directed downward in the lower preload portion. Act on.

Therefore, the required preload is applied to the three bearings 6a, 6b, 6c, and the rotary shaft 5 is rotated without swinging.

Instead of the above configuration, the second preload B can be set to be larger than the first preload A (B
<A). With this setting, the first preload load a acts upward on the outer ring 12a of the fixed bearing 6a, and the second preload load B and the first preload load A act on the upper preload bearing 6b. The load (B-A) of the difference of the above acts on the lower preload bearing 6c, and the second preload B acts on the lower preload bearing 6c in the lower direction. Therefore, in this case, a relatively large preload B acts on the bearing 6c having a large structural outer diameter, and a relatively small preload (A, BA) on the bearings 6a, 6b having a small outer diameter due to the structure. Thus, in addition to the above-described effects, there is an advantage that the life of each bearing 6a, 6b, 6c is further extended.

The magnetic disk as a recording member is attached to the outer circumference of the outer rotor.

The present invention is not limited to the illustrated embodiment, and design changes can be freely made without departing from the gist of the present invention.

[Effect of device]

According to the outer rotor type motor of the present invention, since the rotating shaft 5 is supported by the three bearings 6a, 6b, 6c, the supporting rigidity of the rotating shaft 5 can be increased, and especially the boss portion 14 is provided. Since the outer diameter of the bearing is larger than that of other bearings, the rigidity of the motor can be further increased while making the motor compact.

Further, since the outer diameters of the bearing 6a on the one end side and the intermediate bearing 6b arranged in the cylindrical portion 9 are smaller than the bearings on the other end side, the outer diameter of the cylindrical portion 9 of the housing 4 can be reduced. Thus, the space between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the outer rotor can be increased.

Therefore, the stator 19 having a large diameter can be arranged in this large space, and the torque of the motor can be increased.

Furthermore, by appropriately setting the preloads of the first preload applying means and the second preload applying means, the three bearings 6 are
Preload as required can be applied to a, 6b, 6c.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention. 2 ... One end, 3 ... Outer rotor, 4 ... Housing, 5 ... Rotating shaft, 6a, 6b, 6c ... Bearing, 9
...... Cylindrical part, 10 ...... Housing flanges, 16a, 16b ......
Elastic means (elastic member).

Claims (1)

[Scope of utility model registration request] 1. A housing 4, a rotary shaft 5 which is rotatable relative to the housing 4, an outer rotor 3 fixed to one end 2 of the rotary shaft 5, and an outer rotor 3. In an outer rotor type motor including a rotor magnet 8 and a stator 19 mounted on the housing 4, the housing 4 includes a cylindrical portion 9 and a boss portion provided at an end of the cylindrical portion 9. 14 and a housing flange 10 provided on the boss portion 14, and three bearings 6a, 6b, 6c are interposed between the housing 4 and the rotary shaft 5 at intervals in the axial direction. The bearing 6a on the one end side and the bearing 6b on the middle side are arranged on the cylindrical portion 9, the bearing 6c on the other end side is arranged on the boss portion 14, and the outer diameter thereof is the bearing 6a on the one end side and the intermediate portion 6a. Bearing 6b
First preload applying means for applying a first preload to both bearings 6a, 6b is disposed between the bearing 6a on the one end side and the intermediate bearing 6b. A second preload applying means for applying a second preload to the bearings 6b, 6c is disposed between the intermediate bearing 6b and the bearing 6c on the other end side. Outer rotor type motor.