# US 8,786,150 B2 · Rotor shaft and AC generator for vehicle

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- Number: US 8,786,150 B2
- Document ID: US8786150B2
- Status: Granted
- Kind: B2
- Application number: 13/009,617
- Filed: 2011-01-19
- Published: 2012-03-08
- Granted: 2014-07-22
- Earliest claimed: 2010-09-02
- Assignees: Mitsubishi Electric Corporation
- Applicants: Shinichiro Minami; Takahiro Kimura; Kazunori Tanaka
- Inventors: Shinichiro Minami; Takahiro Kimura; Kazunori Tanaka
- Web page: https://patentgrep.com/patent/US8786150B2

## CPC

- H02K 5/1732: {radially supporting the rotary shaft at both ends of the rotor (H02K5/1737 takes precedence)}
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})

## Abstract

A rotor shaft is supported in a rotatable manner at both ends by bearings respectively disposed to a housing forming a part of a stator and provided with a positioning portion of the bearing in at least one shaft end. The positioning portion is formed of an annular step-like rise portion that abuts on a circular arc surface provided to an inner ring corner of the bearing. A rotor shaft capable of holding the bearing in a stable manner over a long period is thus obtained without increasing the number of components and the numbers of working processes and assembly man-hours for the shaft. It thus becomes possible to solve problems, such as an increase in cost due to a large amount of working margin and increases of the direct material cost and in weight due to a larger finishing diameter of the shaft.

## Claims

### Claim 1

A rotor shaft supported in a rotatable manner at both ends by bearings respectively disposed to a housing forming a part of a stator and provided with a positioning portion of the bearing in at least one shaft end,
wherein the positioning portion is formed of an annular step-like rise portion that abuts on a circular arc surface provided to an inner ring corner of the bearing; and
an annular clearance groove used to release chips generated by grinding is provided to an insertion side of the bearing to be adjacent to the annular step-like positioning portion.

### Claim 2 (depends on 1)

The rotor shaft according to claim 1, wherein:
the rise portion is a circular arc surface that abuts on the circular arc surface of the inner ring corner.

### Claim 3 (depends on 1)

The rotor shaft according to claim 1, wherein:
the annular step-like positioning portion is provided to at least one point in a circumferential direction.

### Claim 4 (depends on 1)

The rotor shaft according to claim 1, wherein:
a groove side wall of the annular clearance groove and a circular arc surface of the rise portion are connected in a shape of a smooth curved surface.

### Claim 5 (depends on 2)

An AC generator for vehicle comprising:
a stator provided in a housing that holds a front bearing and a rear bearing,
wherein:
the stator has a rotator shaft supported on the front bearing and the rear bearing in a rotatable manner;
the rotor shaft is provided with an axial direction positioning portion of at least one of the bearings; and
the rotor shaft is formed of the rotor shaft set forth in claim 2.