Rotor for rotating electric machine

Patent metadata

Field	Value
Publication number	US-10110099-B2
Application number	US-201214361202-A
Country	US
Kind code	B2
Filing date	Mar 8, 2012
Priority date	Mar 8, 2012
Publication date	Oct 23, 2018
Grant date	Oct 23, 2018

Abstract

In a rotor of the present invention, an interference is set to have a relationship so that an inner diameter of a press-fit projecting portion before press-fitting is smaller than a diameter of a shaft, and in the inner wall surface, a non-projecting portion is formed without projecting portions on a portion in which a weld line is generated by the molding.

First claim

The invention claimed is:

1. A rotor for a rotating electric machine, comprising:
a shaft having an end portion with a smooth circumferential surface;
a slip ring device press-fitted over the shaft, the slip ring device comprising:
a first ring and a second ring disposed coaxially so as to be separated away from each other, the first ring and the second ring being electrically connected to a rotor coil;
a molded-body main body formed of a resin by molding, for retaining the first ring and the second ring in an insulated fashion; and
a press-fit projecting portion comprising a plurality of projecting portions and a plurality of grooves both extending along an axial direction formed on an inner wall surface of a hole of the molded-body main body into which the shaft is press-fitted, the grooves of the plurality of grooves being provided between adjacent projecting portions of the plurality of projecting portions,

wherein an interference is set to have a relationship so that an inner diameter of the press-fit projecting portion before press-fitting is smaller than a diameter of the shaft and is set based on a difference between a thermal expansion coefficient of the molded-body main body and a thermal expansion coefficient of the shaft,
wherein the inner wall surface comprises a non-projecting portion without the plurality of projecting portions, which is formed on a portion in which a weld line is generated by the molding,
wherein the non-projecting portion extends circumferentially about the inner wall surface a circumferential distance greater than each groove of the plurality of grooves of the press-fit projecting portion,
wherein the non-projecting portion comprises a first non-projecting portion provided on a first axial end portion of the molded-body main body and a second non-projecting portion provided on a second axial end portion of the molded-body main body,
wherein the first non-projecting portion has an axial size of 3 mm or larger from a first end surface of the molded-body main body, and
wherein the second non-projecting portion has an axial size of 3 mm or larger from a second end surface of the molded-body main body.

2. A rotor for a rotating electric machine according to claim 1 ,
wherein the shaft is formed of carbon steel S48C, whereas the molded-body main body is formed of a polyphenylene sulfide resin (PPS resin).

3. A rotor for a rotating electric machine according to claim 1 ,
wherein the non-projecting portion is intermittently formed along a circumferential direction of the inner wall surface.

4. A rotor for a rotating electric machine according to claim 1 ,
wherein the non-projecting portion is intermittently formed along an axial direction of the inner wall surface.

5. A rotor for a rotating electric machine according to claim 1 ,
wherein the non-projecting portion is formed on the inner wall surface on a press-fit side of the shaft, and
wherein the shaft comprises a distal end portion having a smooth surface fitted to the press-fit projecting portion and a projecting portion to be press-fitted that is fitted to the non-projecting portion.

6. A rotor for a rotating electric machine according to claim 1 ,
wherein the rotating electric machine comprises an AC generator for a vehicle.

7. A rotor for a rotating electric machine according to claim 1 ,
wherein the interference is set to exceed an amount of expansion determined to occur between the molded-body main body and the shaft as a result of the difference between the thermal expansion coefficient of the molded-body main body and the thermal expansion coefficient of the shaft.

Assignees

• Imazawa Yoshiro
• Minami Shinichiro
• Shibagaki Hitoshi
• Tanaka Kazunori
• Mitsubishi Electric Corp

Inventors

• Imazawa Yoshiro
• Minami Shinichiro
• Shibagaki Hitoshi
• Tanaka Kazunori

Classifications

• H02K15/12

  Impregnating, moulding insulation, heating or drying of windings, stators, rotors or machines · CPC title

• H01R39/08

  Slip-rings · CPC title

• H01R43/10

  Manufacture of slip-rings · CPC title

• H02K13/003 Primary

  Structural associations of slip-rings · CPC title

• H02K7/003

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