Motor casing made of resin

• US 5,218,256 A
• Filed: 02/25/1992
• Issued: 06/08/1993
• Est. Priority Date: 05/31/1990
• Status: Expired due to Term

• Current Assignee: Mitsuba Corporation
• Original Assignee: Mitsuba Electric Manufacturing Company Limited
• Inventors: Ochiai, Takao, Umezawa, Takao
• Primary Examiner(s): Skudy, R.
• Assistant Examiner(s): TSO, EDWARD H
• Application Number:
  US07/841,059
• Time in Patent Office: 469 Days
• Field of Search: 310/90, 310/42, 310/43, 310/45, 310/89, 384/275, 384/276, 384/282, 384/295, 384/507, 384/513, 384/617, 384/441, 384/428, 384/DIG. 905
• US Class Current: 310/90
• CPC Class Codes: B29C 45/0053 combined with a final operation, e.g. shaping injection-compression moulding B29C45/561
• CPC Class Codes: B29C 65/665 using shrinking during cooling
• CPC Class Codes: B29C 66/112 Single lapped joints
• CPC Class Codes: B29C 66/12441 being a single wall
• CPC Class Codes: B29C 66/131 Single flanged joints, i.e. one of the parts to be joined being rigid and flanged in the joint area
• CPC Class Codes: B29C 66/5344 said single elements being substantially annular, i.e. of finite length, e.g. joining flanges to tube ends B29C66/5346 takes precedence
• CPC Class Codes: B29C 66/612 Making circumferential joints
• CPC Class Codes: B29L 2031/749 Motors
• CPC Class Codes: F16B 4/006 Shrinkage connections, e.g. assembled with the parts being at different temperature
• CPC Class Codes: F16C 2380/26 Dynamo-electric machines or combinations therewith, e.g. electro-motors and generators in general H02K
• CPC Class Codes: F16C 35/02 in the case of sliding-contact bearings
• CPC Class Codes: H02K 15/14 Casings; Enclosures; Supports
• CPC Class Codes: H02K 5/08 Insulating casings

Abstract

Disclosed are a motor casing made of a resin and a method of manufacturing such a motor casing. A bearing for rotatably supporting a core shaft of a rotor core is inserted into a bearing seat portion of the motor casing when the temperature of the resin material which forms the bearing seat portion is substantially at the glass transition temperature thereof or above, the resin material being cooled to a room temperature.

Claims

1. A motor casing formed form a thermoplastic resin material, comprising:

a bearing seat portion formed in the motor casing, for supporting a bearing and having an inner end within the motor casing;

a bearing seat formed inthe bearing seat portion, the bearing positioned in the bearing seat for rotatably supporting a motor shaft and having an outer diameter; and

a shift prevention portion positioned on the inner end of the bearing seat portion, and having an inner diameter smaller than the outer diameter of the bearing.

2. The motor casing of claim 1, wherein:

the bearing has a first coefficient of thermal expansion; and

the shift prevention portion is a resin material having a second coefficient of thermal expansion;

the first and second coefficients of thermal expansion being related such that the inner diameter of the shift prevention portion is maintained smaller than the outer diameter of the bearing upon thermal expansion of the bearing and resin material.

3. A motor casing formed of a thermoplastic resin material, comprising:

a bearing seat portion formed inthe motor casing, for support a bearing and having an inner end within the motor casing;

a bearing seat formed in the bearing seat portion, the bearing positioned in the bearing seat for rotatably supporting a motor shaft and having an outer diameter;

a shift prevention portion positioned on the inner end of the bearing seat portion, and having an inner diameter smaller than the outer diameter of the bearing; and

a bearing inserting portion positioned on the inner end of the bearing seat portion and having an inner diameter larger than the outer diameter of the bearing.

4. The motor casing of claim 3, further comprising:

the bearing has a first coefficient of thermal expansion; and

the shift prevention portion is a resin material having a second coefficient of thermal expansion;

first and second coefficient of thermal expansion being related such that the inner diameter of the shift prevention portion is maintained smaller than the outer diameter of the bearing upon thermal expansion of the bearing and resin material.

5. A motor casing formed from a thermoplastic resin material, comprising:

a bearing seat portion integrally formed in the motor casing, for supporting an annular bearing and having an inner end within the motor casing;

a bearing seat integrally formed in the bearing seat portion, an inner periphery of the bearing seat defining a cylindrical opening in the motor casing, the annular bearing positioned in the cylindrical bearing seat to rotatably support a motor shaft; and

a shift prevention portion integrally formed on the inner end of the bearing seat portion and having an inner diameter smaller than an outer diameter of the annular bearing.

6. The motor casing of clam 5, wherein the annular bearing is a solid member.