US 6,125,975 A · Sealed electromagnetic brake

Abstract

An electromagnetic disk brake is compact, self-sealing, self-contained, has relatively few components, and is relatively easy to fabricate and to install when compared to traditional electromagnetic disk brakes. Self-containment and self-sealing are achieved by providing a skirt on the field cup that extends over the remaining moving components of the brake and that is attached, preferably by a press-fit, to a reaction plate at the inner end of the brake. The need for stand-offs to set the air gap of the brake can be eliminated by suitable control of the press-fitting of the field cup onto the reaction plate. For electric motor braking applications, the reaction plate can form the endbell of the electric motor, thereby combining the endbell, mounting plate and reaction plate in a single plate. Simplicity and ease of assembly of a spring-applied brake are enhanced further by employing a single compression spring at the center of the brake rather than a plurality of peripherally-spaced springs. Finally, in applications in which the brake includes a manual release lever, the brake may incorporate an improved release lever anti-rattle arrangement.

Claims20

Dependent claims

An electromagnetic brake for braking a shaft which is rotatable about an axis of rotation, said brake comprising:

(A) a friction disk which is attachable to the shaft so as to rotate about the axis of rotation of the shaft and to move axially relative to the axis of rotation of the shaft, said friction disk having first and second axially opposed friction surfaces;
(B) a stationary reaction plate which is axially aligned with said friction disk;
(C) a clapper plate which (1) is fixed from rotation with respect to the axis, and (2) is movable axially between (a) a first, unactuated position in which said brake is not applied and (b) a second, actuated position in which said friction disk is clamped between said clapper plate and said reaction plate to apply said brake;
and
(D) a field cup assembly including
(1) a coil which is selectively energizeable to drive said clapper plate to move from one of said first and second positions to the other of said first and second positions, and
(2) a field cup including (a) an axially-outer body which houses said coil, and (b) a skirt which extends from said body, over said clapper plate and said friction disk, and to said reaction plate, said skirt being attached to said reaction plate so as to encase said clapper plate, said friction disk, and at least an inner axial surface of said reaction plate.

4 more elements

An electromagnetic brake for braking a shaft which is rotatable about an axis of rotation, said brake comprising:

(A) a friction disk which is attachable to the shaft so as to rotate about the axis of rotation of the shaft and to move axially relative to the axis of rotation of the shaft, said friction disk having first and second axially opposed friction surfaces;
(B) a stationary reaction plate which is axially aligned with said friction disk, an outer periphery of an outer axial surface of said reaction plate having a step formed therein;
(C) a clapper plate which (1) is fixed from rotation with respect to the axis, and (2) is movable axially between (a) a first, unactuated position in which said brake is not applied and (b) a second, actuated position in which said friction disk is clamped between and engages said clapper plate and said reaction plate to apply said brake;
(D) a field cup assembly including
(1) a coil which is selectively energizeable to drive said clapper plate to move from one of said first and second positions to the other of said first and second positions, and
(2) a field cup including (a) an axially-outer body which houses said coil, and (b) a skirt which extends axially inwardly from said body, over said clapper plate and said friction disk, and to said reaction plate, said skirt being press-fit onto said step of said reaction plate so as to encase said clapper plate, said friction disk, and at least said inner axial surface of said reaction plate.

3 more elements

An electromagnetic park-and-hold disk brake for a rotatable output shaft of an electric motor, said brake comprising:

(A) a stationary endbell which is configured to cover an opening in the motor, an outer periphery of an outer axial surface of said endbell having a step formed therein;
(B) a friction disk which is attachable to the shaft so as to rotate about the axis of rotation of the shaft and to move axially relative to the axis of rotation of the shaft, said friction disk having first and second axially opposed friction surfaces;
(C) a clapper plate which (a) has a plurality of scallops formed in an outer radial periphery thereof, and (b) is movable axially between (i) a first, unactuated position in which said brake is not applied and (ii) a second, actuated position in which said friction disk is clamped between and engages said clapper plate and said endbell to apply said brake;
(D) a field cup assembly including
(1) a coil which is selectively energizeable to drive said clapper plate to move from said second position to said first position to release said brake, and
(2) a field cup including a) an axially-outer body which houses said coil, said field cup including a sealed axially-outer surface, b) a sealed radially-outer surface, and c) an inner axial surface having formed therein (i) an annular groove in which said coil is mounted and (ii) an axially-central recess, and (iii) a sealed skirt which extends axially inwardly from said body, over said clapper plate and said friction disk, and to said endbell, a stepped inner axial end of said skirt being press-fit onto said step of said endbell so as to sealingly encase said clapper plate, said friction disk, and at least said inner axial surface of said endbell;
(E) a gasket clamped axially between said inner axial end of said skirt and an axial face of said step;
(F) a compression spring which is disposed in said recess in said field cup and which biases said clapper plate towards said second position, said compression spring being the sole applicator spring of said brake;
and
(G) a plurality of bolts which extend through holes in an outer axial end of said field cup, through said scallops in said clapper plate, through holes in said endbell, and into a support of said motor, wherein
said bolts prevent rotation of said clapper plate, and said brake lacks stand-offs, and wherein
an air gap of said brake is set by setting a distance through which said skirt is press-fit onto said step.

9 more elements

A method comprising

(A) providing an electromagnetic brake comprising:
(1) a friction disk which is attachable to the shaft so as to rotate about the axis of rotation of the shaft and to move axially relative to the axis of rotation of the shaft, said friction disk having first and second axially opposed friction surfaces;
(2) a stationary reaction plate which is axially aligned with said friction disk;
(3) a clapper plate which (1) is fixed from rotation with respect to the axis, and (2) is movable axially between (a) a first, unactuated position in which said brake is not applied and (b) a second, actuated position in which said friction disk is clamped between said clapper plate and said reaction plate to apply said brake;
and
(4) a field cup assembly including
(a) a coil which is selectively energizeable to drive said clapper plate to move from one of said first and second positions to the other of said first and second positions;
and
(b) a field cup including (i) an axially-outer field cup which houses said coil, and (ii) a skirt which extends axially inwardly from said body, over said clapper plate and said friction disk, and to said endbell;
(B) aligning mounting holes in said field cup with mounting holes in said endbell;
and then
(C) press-fitting said skirt onto said endbell so as to encase said clapper plate, said friction disk, and at least an inner axial surface of said endbell in said skirt.

9 more elements

Dependencies are inferred from the claim text.

Sealed electromagnetic brake

Life of this patent

Sealed electromagnetic brake

Life of this patent

Abstract

Claims20