Electric motor equipped with inner blocking brake

• US 4,560,895 A
• Filed: 11/07/1983
• Issued: 12/24/1985
• Est. Priority Date: 11/09/1982
• Status: Expired due to Term

• Current Assignee: Mavilor Systemes SA Swiss Corporation
• Original Assignee: Mavilor Systemes SA
• Inventors: Zahner, Pierre W.
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): REBSCH, DONALD
• Application Number:
  US06/549,590
• Time in Patent Office: 778 Days
• Field of Search: 310/77, 310/102 A, 310/105, 310/184, 310/88, 308/196, 188/161, 188/162, 188/267
• US Class Current: 310/77
• CPC Class Codes: H02K 7/1025 using axial electromagnets with generally annular air gap

Abstract

The motor has two motor flanges (1,2) which form the stator with stator magnets projecting axially inward from the inner sides (11,12) of the flanges, the magnets being distributed along a circle coaxial with the motor axis, and a slightly conical rotor (9) in the air space between opposing stator magnets (11,12). On the output side of one motor half, and facing outwardly, is an annular space defined by the stator magnet (11) on the output side of the motor flange (1). A blocking brake (18 to 23) is mounted in a space-saving manner, with the stationary half of the brake (18 to 21) placed in an opening made for it in the outer flange piece (18) in the motor flange (1) and attached to it. The rotating half of the brake (22,23) is attached to the motor shaft (6). In this way, the motor and friction brake form a compact structural unit whose dimensions are not greater than those of an ordinary motor housing.

Claims

1. Electric motor equipped with a blocking brake and having a magnetic field running at least partially axially, said motor having two flanges lying axially opposite one another to form a stator and to define axial outer boundaries for said motor, axially inwardly projecting stator magnets positioned on each flange along a circle coaxial to a motor shaft, and a rotor in an air space between the opposing stator magnets, the blocking brake being a disc brake biased in the braking condition and including an electromagnet for easing the brake by counteracting the brake action when activated, comprising:

said blocking brake being installed completely within one axial half of the motor essentially in an annular space circumscribed by the stator magnets of one motor flange;

a flange piece made of a ferromagnetic material mounted to said one motor flange to define a stationary portion of the brake; and

an inner pole ring formed on said flange piece coaxially with said motor shaft and being adapted to rotatably receive the motor shaft, an induction winding of the electromagnet being disposed about said pole ring.

2. Motor according to claim 1, in which the flange piece is fitted in an opening made for it in the motor flange and fastened to it with screws.

3. Motor according to claim 2, in which the opening of the motor flange has an inner wall having an outer step and an inner step of smaller diameter than the outer step, the flange piece of the stationary portion of the brake being disposed only in the outer step.

4. Motor according to claim 1 in which the stationary portion of the brake has a permanent magnet in addition to the electromagnet on the inner pole ring, a rotating portion of the brake including and being situated on a coaxial flange hub fastened to the motor shaft, the flange hub having a radially projecting flange, and a friction ring mounted for axial movement between said hub flange and said inner pole, but being fixed against rotation with respect to said hub, the flange piece and the inner pole ring being made in one piece.

5. Motor according to claim 2, in which the flange piece is fitted in an opening of the motor flange which includes an inner wall having an outer step and an inner step of smaller diameter than the outer step, the flange piece of the stationary portion of the brake being disposed only in the outer step, ball bearing means for receiving said shaft, at least a part of which is mounted within said inner pole ring and is constructed to be retained therein by means of a friction fit, the one-piece part comprising the flange piece and pole ring being constructed and arranged to transfer radial forces, especially oscillations of the shaft, to the motor flange.

6. Motor according to claim 4, further comprising a generally cylindrical dust cover mounted on the periphery of the hub flange of the rotating portion of the brake and extending axially therefrom to cover the friction ring part of the stationary portion of the brake, which it overlaps with minimal play.

7. Motor according to claim 1 in which the rotor has a commutator on one side, the brake in the motor half faces away from the commutator and this half of the motor faces the output side of the motor.

8. In an electric motor having a predefined axis of rotation and friction brake, the motor being constructed to have a magnetic field therein oriented at least partially axially, said motor comprising:

axially spaced, opposed flanges defining axial outer boundaries of a housing for said motor;

axially inwardly projecting magnets positioned on at least one of said flanges and about said axis to define a magnetic component of said motor;

an electrical component of said motor mounted for rotation about said axis relative to said magnetic component at a position intermediate said flanges; and

said friction brake being selectively electrically actuable and being disposed entirely within said motor housing essentially in an annular space circumscribed by the magnets.