Integral bearing type electric motor

• US 5,698,919 A
• Filed: 10/23/1995
• Issued: 12/16/1997
• Est. Priority Date: 11/09/1992
• Status: Expired due to Term

• Current Assignee: Minebea Kabushiki-Kaisha
• Original Assignee: Minebea Kabushiki-Kaisha
• Inventors: Obara, Rikuro
• Primary Examiner(s): Laballe, Clayton E.
• Application Number:
  US08/546,753
• Time in Patent Office: 785 Days
• Field of Search: 310/67 R, 310/156, 310/90, 360/98.07, 360/99.04, 360/99.08, 384/227
• US Class Current: 310/90
• CPC Class Codes: F16C 19/08 with two or more rows of balls
• CPC Class Codes: H02K 5/1735 radially supporting the rotary shaft at only one end of the rotor H02K5/1737 takes precedence
• CPC Class Codes: H02K 5/1737 radially supporting the rotor around a fixed spindle; radially supporting the rotor directly

Abstract

An integral bearing type electric motor is disclosed, which comprises a bearing body including a spindle, a sleeve surrounding the spindle, an inner or outer ring fitted in or on the spindle, and balls provided between the spindle and sleeve, between the spindle and outer ring or between the inner ring and sleeve. A hub for the rotor of the motor, a flange for the base of the motor or a stator yoke holder is formed by molding together with the sleeve, spindle or inner ring of the bearing body. The number of components is reduced, the number of assembling steps can be reduced, and reduction of the cost of manufacture can be expected.

Claims

1. An integral bearing type electric motor comprising:

a stator (2, 3,

     4);

a unitary, one-piece monolithic machined rotor, said one-piece machined rotor including in its monolithic structure a sleeve (10) and a hub (9) including a disc;

a bearing assembly (5, 8,

     10), said bearing assembly including a stepped spindle (5) having a large diameter portion and a small diameter portion;

said sleeve (10) surrounding said spindle;

said large diameter portion of said spindle (5) formed with an outer race (6) for one ball row, balls (13) in said one row being provided between said outer race (6) and an inner race (11) formed in said sleeve (10);

an inner ring (8) fitted on the small diameter portion of said spindle (5) and having an outer race (7); and

balls (14) in another row being provided between said inner ring outer race (7) and a corresponding inner race (12) formed in said sleeve (10),

said sleeve being integrally machined with said hub in said unitary, monolithic rotor of said electrical motor.

2. An integral bearing type electric motor as claimed in claim 1, wherein said stator (2, 3, 4) comprises a stator yoke (4) with a coil (3) wound thereon, and a cylindrical yoke holder (2, 2a) for positioning said yoke.

3. An integral bearing type electric motor as claimed in claim 2, including a magnet (15) mounted on the hub (9) so as to face said yoke (4).

4. An integral bearing type electric motor as claimed in claim 3, wherein said magnet (15) is mounted on an inner periphery of said hub (9).

5. An integral bearing type electric motor as claimed in claim 3, wherein said magnet (15) is mounted on an outer periphery of said sleeve (10).

6. An integral bearing type electric motor comprising:

a stator;

a unitary, one-piece integrated machined rotor, said one-piece machined rotor including therein a sleeve (10) and a hub (9) including a disc;

a bearing assembly (5, 8,

     10), said bearing assembly including a spindle (5);

said, sleeve (10) surrounding said spindle;

inner rings (8)(8) fitted on said spindle (5) and having respective outer races (7)(7); and

balls (14)(14) being provided between said outer races (7)(7) and double-row inner races (12)(12) formed in said sleeve (10),

said sleeve being integrally formed by machining as said unitary, one-piece, structure with said hub (9) as said rotor of said electrical motor from a one-piece blank.

7. An integral bearing type electric motor as claimed in claim 6, wherein said stator comprises a stator yoke (4) with a coil (3) wound thereon, and a cylindrical yoke holder (2, 2a) for positioning said yoke.

8. An integral bearing type electric motor as claimed in claim 7, including a magnet (15) mounted on the hub (9) so as to face said yoke (4).

9. An integral bearing type electric motor as claimed in claim 8, wherein said magnet (15) is mounted on an inner periphery of said hub (9).

10. An integral bearing type electric motor as claimed in claim 8, wherein said magnet (15) is mounted on an outer periphery of said sleeve (10).

11. An integral bearing type electric motor comprising:

a stator;

a unitary, one-piece machined rotor, said one-piece machined rotor including a monolithic structure incorporating therein a sleeve (10) and a hub (9) including a disc;

a bearing assembly, said bearing assembly including a spindle (5);

said sleeve (10) surrounding said spindle; and

balls (13)(13) being provided between double-row outer races (6)(6) formed on said spindle (5) and double-row inner races (11)(11) formed at said sleeve (10),

said sleeve being integrally machined with said hub from a one-piece blank as said unitary, one-piece, rotor of said electrical motor.

12. An integral bearing type electric motor as claimed in claim 11, further comprising a pair of outer rings (17)(17) positioned within said sleeve, said outer rings having respective inner races (11)(11) therein, wherein said balls (13)(13) are positioned between said double-row outer races (6)(6) and said inner races (11)(11) formed in said outer rings (17)(17).

13. An integral bearing type electric motor as claimed in claim 11, wherein said double-row inner races (11, 11) are formed in said sleeve.

14. An integral bearing type electric motor as claimed in claim 11, wherein said stator comprises a stator yoke (4) with a coil (3) wound thereon, and a cylindrical yoke holder (2, 2a) for positioning said yoke.

15. An integral bearing type electric motor as claimed in claim 14, including a magnet (15) mounted on the hub (9) so as to face said yoke (4).

16. An integral bearing type electric motor as claimed in claim 15, wherein said magnet (15) is mounted on an inner periphery of said hub (9).

17. An integral bearing type electric motor as claimed in claim 15, wherein said magnet (15) is mounted on an outer periphery of said sleeve (10).