Motor shaft, motor and motor assembly

Patent metadata

Field	Value
Publication number	US-2016204671-A1
Application number	US-201614993276-A
Country	US
Kind code	A1
Filing date	Jan 12, 2016
Priority date	Jan 13, 2015
Publication date	Jul 14, 2016
Grant date	—

Abstract

A motor shaft is configured to be press-fitted into a hole formed in a press-fitted component from a front end side in an axial direction. The motor shaft includes: a shaft body; a first annular projection portion that protrudes outwardly in a radial direction of the shaft body and is brought into contact with an inner circumferential surface of the hole the first annular projection portion being positioned at a first position; and a second annular projection portion that protrudes outwardly in the radial direction of the shaft body and is brought into contact with the inner circumferential surface of the hole, the second annular projection portion being positioned at a second position that is shifted from the first position toward a rear end side in the axial direction of the shaft body.

First claim

What is claimed is:

1 . A motor shaft that is press-fitted into a hole formed in a press-fitted component from a front end side in an axial direction, the motor shaft comprising:
a shaft body; a first annular projection portion that protrudes outwardly in a radial direction of the shaft body and is brought into contact with an inner circumferential surface of the hole the first annular projection portion being positioned at a first position; and a second annular projection portion that protrudes outwardly in the radial direction of the shaft body and is brought into contact with the inner circumferential surface of the hole, the second annular projection portion being positioned at a second position that is shifted from the first position toward a rear end side in the axial direction of the shaft body.

2 . The motor shaft according to claim 1 ,
wherein the first annular projection portion is separated from the second annular projection portion.

3 . The motor shaft according to claim 2 ,
wherein the first annular projection portion is positioned on a press-fitting surface of the shaft body where the press-fitted component is inserted at the first position near the front end of the shaft body, and wherein the second annular projection portion is positioned on the press-fitting surface near the rearmost end of the press-fitting surface.

4 . The motor shaft according to claim 1 ,
wherein an outer diameter of the first annular projection portion is smaller than that of the second annular projection portion.

5 . The motor shaft according to claim 1 ,
wherein the first annular projection portion is provided with a plurality of first annular projections.

6 . The motor shaft according to claim 1 ,
wherein the second annular projection portion is provided with a plurality of second annular projections.

7 . The motor shaft according to claim 1 ,
wherein the motor shaft is made of a material having hardness lower than that of the press-fitted component.

8 . The motor shaft according to claim 7 ,
wherein the motor shaft is made of SUS303 stainless steel.

9 . A motor comprising:
the motor shaft according to claim 1 ; a magnet attached to the motor shaft; and a coil that rotates the motor shaft along with the magnet by electromagnetic interaction with the magnet.

10 . A motor assembly comprising:
the motor according to claim 9 ; and the press-fitted component.

11 . The motor assembly according to claim 10 ,
wherein the hole of the press-fitted component includes: a first press-fitting hole positioned in the vicinity of an entrance into which the motor shaft is press-fitted and having a first inner circumferential surface that is brought into contact with the second annular projection portion in a state where the second annular projection portion bites into the first inner circumferential surface; and a second press-fitting hole positioned at deeper side from the entrance with an inner diameter smaller than that of the first press-fitting hole and having a second inner circumferential surface that is brought into contact with the first annular projection portion in a state where the first annular projection portion bites into the second inner circumferential surface.

12 . The motor assembly according to claim 11 ,
wherein a distance between the first annular projection portion and the second annular projection portion is smaller than a depth of the first press-fitting hole.

Assignees

• Minebea Co Ltd

Inventors

• Otsuka Makoto
• Kamogi Yutaka
• Ohmura Jun

Classifications

• F16D1/072

  involving plastic deformation (plastic welding F16D1/068) · CPC title

• H02K15/02 Primary

  of stator or rotor bodies · CPC title

• F16C3/02

  Shafts; Axles · CPC title

• F16D1/0858

  due to the elasticity of the hub (including shrink fits) · CPC title

• H02K7/003 Primary

  Couplings; Details of shafts (means for mounting rotors on shafts H02K1/28) · CPC title