JPH0644364U - Motor bearing holder - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a bearing holder for a motor, which can reduce the occurrence of cracks even when a sufficient fixing strength is secured. [Structure] Bearing holder 10, into which bearings 8 and 9 are press-fitted,
In the inner peripheral surface of the bearing accommodating hole 14 of No. 11, a substantially circular arc-shaped recess 15
Are formed at substantially equal intervals. Since the outer peripheral surfaces of the bearings 8 and 9 and the entire inner peripheral surface of the bearing housing hole in the portion of each protrusion 15P formed in each arcuate recess 15 are brought into pressure contact with each other,
The occurrence of cracks is reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a motor bearing holder applied to a small motor used in various audio devices and other devices.

[0002]

[Prior art]

 Bearing holders for small motors are often made of synthetic resin, which is superior in cost. As shown in FIG. 6, the bearing holder 18 is formed in a disc shape, and a circular bearing accommodating hole 19 is provided at the center of the bearing holder 18, so that the bearing 20 is press-fitted and fixed. FIG. 8 shows a cross-sectional structure after the bearing 20 is press-fitted and fixed.

[0003]

[Problems to be solved by the device]

 By the way, the conventional motor bearing holder has a problem that cracks occur when sufficient fixing strength is secured. That is, since the bearing housing hole 19 of the bearing holder 18 is circular, when the bearing 20 is press-fitted and fixed as shown in FIG. Since the pressure contact is weakened or does not contact the portion A, the press-in pressure concentrates on the specific portion A, and cracks 21 occur as shown in FIG.

Further, the bearing holder made of synthetic resin has a high degree of freedom in the shape to be molded, but on the other hand, it is the difference between the inner diameter L1 of the bearing housing hole 19 and the outer diameter L2 of the bearing 20. The cost is excessively large, and the manufacturing error is larger than in turning etc., so cracks are more likely to occur. In addition, in order to avoid cracking while ensuring sufficient fixing strength, the bearing holder 18 must be made thicker, which makes it impossible to downsize and flatten the motor.

The present invention has been made in consideration of the above problems, and an object thereof is to provide a bearing holder for a motor that can reduce the occurrence of cracks even when sufficient fixing strength is secured. .

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention is a motor having a bearing holder in which a bearing for rotatably supporting a rotating shaft that faces a stator part and rotates integrally with a rotor part is press-fitted and fixed. A plurality of substantially arcuate recesses are formed at substantially equal intervals on the inner peripheral surface of the bearing housing hole of the bearing holder into which the bearing is press-fitted.

[0007]

[Action]

 Since a plurality of generally arc-shaped recesses are formed at approximately equal intervals on the inner peripheral surface of the bearing housing hole of the bearing holder into which the bearing is press fitted, when the bearing is press-fitted and fixed in the bearing housing hole, the arc-shaped The outer peripheral surface of the bearing is pressed against the protrusion of the recess almost entirely. Therefore, the injection pressure is not concentrated on a specific part.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a half sectional view showing a motor to which the present invention is applied. A rotor 2 fixed to a rotary shaft 1 has an armature 3 on which a coil 4 is wound, while the armature 3 is Magnets 6 that face each other and constitute the stator 5 are fixed to the inner peripheral surface of the case 7. The rotary shaft 1 is rotatably supported at the upper and lower ends by bearings 8 and 9, respectively, and the bearings 8 and 9 are press-fitted and fixed to bearing holders 10 and 11, respectively. A commutator 12 is fixed to the lower end side of the rotary shaft 1, and a brush 13 supported by a bearing holder 11 is in sliding contact therewith.

FIG. 2 is a perspective view showing the bearing holders 10 and 11 before the bearings 8 and 9 are press-fitted and fixed, and the inner peripheral surface of the bearing housing hole 14 is provided with a plurality of substantially arc-shaped recesses 15 at substantially equal intervals. Has been formed. FIG. 3 shows a cross-sectional structure after the bearings 8 and 9 are press-fitted and fixed in the bearing housing holes 14 of the bearing holders 10 and 11, respectively.

As shown in FIG. 4, the angles θ between the straight lines L connecting the vertices 15T of the adjacent recesses 15 and the center C are substantially equal in any of the directions, and the lengths of the straight lines L are not required. These are almost equal. R1 indicates the radius of the inner diameter of the bearing housing hole 14, R2 indicates the outer radius of the bearings 8 and 9 which are press-fitted and fixed, and 15P indicates the protrusion of each recess 15. Here, the magnitude relationship between L, R1 and R2 is set to L> R1, R2> R1. In addition, R1 is on a circle in contact with each protrusion 15P.

According to such an embodiment, when the bearings 8 and 9 are press-fitted and fixed in the bearing accommodating holes 14, as is apparent from FIG. 3, the outer peripheral surfaces of the bearings 8 and 9 have a plurality of arcuate shapes. All of the protrusions 15P formed in the adjacent portions of the recess 15 are pressed against each other, and are not in contact with each vertex 15T.

FIG. 5 is a characteristic diagram showing the relationship between the interference (horizontal axis) and the pressure input (vertical axis), where a is the characteristic obtained by the embodiment of the present invention and b is the characteristic obtained by the conventional example. ing. M indicates the range of the optimum pressure input. If it becomes higher than the range M of the optimum pressure input, the bearing holder will be cracked. On the other hand, when the pressure is lower than the optimum pressure input range M, sufficient fixing strength cannot be secured.

In the case of the present embodiment, as is apparent from FIG. 3, the pressure contact area between the bearings 8 and 9 and the bearing holders 10 and 11 is small only in the projecting portion 15P, so the characteristic a in FIG. The increase of the press input to becomes slow. Therefore, the range S1 of the proper interference allowance is widened, so that it is possible to secure the optimum pressure input even if there is a manufacturing error in resin molding. S2 indicates the range of the tightening margin of the conventional example.

Further, according to the present embodiment, since the pressure input is shared by the multiple points of each protrusion 15P, the stress per point is significantly smaller than that of the conventional example, and therefore the occurrence of cracks is reduced. can do. Further, in the present embodiment, by making the shape of each recess 15 substantially arcuate, it is possible to eliminate the point where the distortion of the bearing holder, which is generated when the bearing is press-fitted and fixed, is concentrated. On the other hand, when a plurality of V-shaped recesses 16 are provided as shown in FIG. 9, strain is concentrated on each tip 16P, so that a crack 17 occurs due to a rapid temperature change. There is a risk.

For the reasons described above, according to the present embodiment, it is possible to almost completely avoid the occurrence of cracks while ensuring sufficient fixing strength with the bearing holder made of resin. This eliminates the need to increase the thickness of the bearing holder, which makes it possible to downsize and flatten the motor.

The present invention is not limited to a motor with a brush, and the same effect can be obtained when applied to a brushless motor. Further, the present invention can be similarly applied to the case where the bearing holder is made of not only synthetic resin but also other material such as ceramic.

[0017]

[Effect of device]

 As described above, according to the present invention, a plurality of substantially circular arc-shaped recesses are formed at substantially equal intervals on the inner peripheral surface of the bearing housing hole of the bearing holder, so that even when sufficient fixing strength is secured. A bearing holder for a motor that can reduce the occurrence of cracks can be provided.

[Brief description of drawings]

FIG. 1 is a half sectional view showing a motor to which the present invention is applied.

FIG. 2 is a perspective view showing the structure of the bearing holder of the motor of the present invention before press-fitting the bearing.

FIG. 3 is a cross-sectional view showing the structure of the bearing holder of the motor of the present invention after press-fitting the bearing.

FIG. 4 is a schematic diagram illustrating the principle of the present invention.

FIG. 5 is a characteristic diagram showing the relationship between the interference of the bearing holder of the motor and the pressure input.

FIG. 6 is a perspective view showing a conventional example.

FIG. 7 is a perspective view showing a defect of the conventional example.

FIG. 8 is a cross-sectional view showing a defect of the conventional example.

FIG. 9 is a cross-sectional view showing another conventional example.

[Explanation of symbols]

 1 rotating shaft 8 bearing (output side) 9 bearing (counter output side) 10 bearing holder (output side) 11 bearing holder (counter output side) 14 bearing housing hole 15 recess 15T apex 15P protrusion

Claims (1)

[Scope of utility model registration request] 1. A motor having a bearing holder in which a bearing for rotatably supporting a rotating shaft facing the stator portion and rotating integrally with the rotor portion is press-fitted and fixed, and the bearing of the bearing holder is press-fitted. A bearing holder for a motor, wherein a plurality of substantially arcuate recesses are formed at substantially equal intervals on the inner peripheral surface of the housing hole.