Electric brake adjuster

• US 3,917,035 A
• Filed: 02/18/1975
• Issued: 11/04/1975
• Est. Priority Date: 02/18/1975
• Status: Expired due to Term

• Current Assignee: Edward J. Woods, Richard S. Grewette
• Original Assignee: Edward J. Woods, Richard S. Grewette
• Inventors: Grewette, Richard S., Woods, Edward J.
• Primary Examiner(s): Reger, Duane A.
• Application Number:
  US05/550,462
• Time in Patent Office: 259 Days
• Field of Search: 188/71.8,71.9,79.5GE,158,161,163,164,196B,196BA
• US Class Current: 188/161
• CPC Class Codes: F16D 2121/20 using electromagnets
• CPC Class Codes: F16D 55/00 Brakes with substantially-radial braking surfaces pressed together in axial direction, e.g. disc brakes similar clutches F16D13/38
• CPC Class Codes: F16D 65/567 for mounting on a disc brake

Abstract

An electromagnetically actuated disc brake provides for adjustment of the magnet pole faces as the brake lining wears so that the faces remain closely adjacent the surface of the disc to be braked so as to minimize the air gap therebetween, but does not engage the disc in brake force transmitting relation during brake actuation. The annular magnet has the field coil mounted in an annular recess and the friction lining secured in the outer portion of the recess andd extending axially from the magnet. The inner and outer peripheries of the magnet have threaded sections or threaded members secured thereto. Annular magnet poles are positioned so that they are threaded on the threaded sections, located radially inward and outward of the friction lining, and have faces immediately adjacent the friction braking surfaces of the disc. When the disc is rotating in a forward direction and the friction lining has worn sufficiently so that the faces of the magnet poles engage the forwardly rotating disc during brake actuation, the drag causes the magnet poles to rotate in the direction of disc rotation, with the thread action causing the poles to move axially away from the disc to maintain their adjustment. A suitable ratchet mechanism is provided for each of the magnet poles so that they can be rotated only in one direction. Therefore when the disc is rotating in the reverse direction the magnet poles cannot be moved by any drag that may occur to thread them toward the disc. The ratchet is manually releasable to readjust the magnet pole positions when the friction lining is replaced.

Claims

1. In an electro-magnetically actuated brake having a field coil, an annular magnet, a friction element secured to and extending from said magnet, and a forwardly and reversibly rotatable member to be braked by frictional engagement of said friction element therewith under a force depending upon the strength of the magnetic field generated in said magnet and said rotatable member by energization of said field coil, mechanism forming a magnetic flux path between said magnet and said rotatable member and including means adjusting said mechanism as said friction element wears to prevent braking force engagement between said mechanism and said rotatable member while permitting braking force engagement between said friction element and said rotatable member, said mechanism comprising:

first and second annular threaded sections respectively provided on the inner and outer peripheries of said annular magnet;

first and second annular magnet poles having threads thereon and threaded on said threaded sections for rotational movement relative to said annular magnet and resultant axial movement as said poles are threaded further onto said threaded section;

said magnet poles having faces immediately adjacent said rotatable member and engageable therewith, upon wear of said friction element and brake energization, sufficiently to be rotated on said magnet in the direction of rotation of said rotatable member during forward rotation of said rotatable member, and by thread action being moved axially away from said rotatable member sufficiently that braking force is exerted on said rotatable member by said friction element and not by said magnet poles;

said magnet and said threaded sections thereof and said magnet poles and said rotatable member providing the magnetic flux path for said brake; and

selectively releasable means on said magnet and saId magnet poles preventing rotation of said magnet poles upon engagement with said rotatable member during reverse rotation of said rotatable member.

2. An electrically actuated disc brake comprising:

a rotatable disc to be braked, a brake actuator including a rotationally stationary friction ring adapted to frictionally engage said disc in braking relation when the brake actuator is actuated, a magnet mounting said friction ring and composed of an inner peripheral magnet pole ring and an outer peripheral magnet pole ring positioned radially adjacent said friction ring and having pole faces positioned axially adjacent said disc, an annular magnet core having an annular axially extending recess opening toward said disc and receiving therein a field coil and said friction ring, an inner and an outer core ring respectively mounted on the inner and outer peripheries of said annular magnet core, said inner core ring and said inner magnet pole ring having mating threads on peripherally adjacent surfaces and said outer core ring and said outer magnet pole ring having mating threads on peripherally adjacent surfaces permitting axial screw movements of said magnet pole rings in one direction axially away from said disc when said magnet pole ring pole faces are moved during brake actuation to engage said disc while said disc is rotating, thereby maintaining a close adjustment of said pole faces to said disc without applying friction braking forces therethrough, and means mounted on said magnet core and limiting screw movements of said magnet pole rings only to the rotational direction resulting in magnet pole ring axial movements away from said disc.