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US 4,804,073 AGranted
Electrically operated disc brake with back-off protector
AssigneeAllied-Signal Inc.
InventorsAlistair G. Taig, Robert W. Jackson, Richard N. DeHays
Life of this patent
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AssigneeAllied-Signal Inc.
InventorsAlistair G. Taig, Robert W. Jackson, Richard N. DeHays
Estimating the term…
The electrically operated disc brake (10, 110, 310, 410) may be operated by either hydraulic pressure and an electric motor or operated solely by means of an electric motor. The electric motor (40, 340, 440) drives a sun gear (52, 352, 452) of a planetary gear assembly (50, 150, 350, 450). The planetary gear assembly (50, 150, 350, 450) includes a fixed ring gear (70, 370, 470) and a rotatable ring gear (80, 180, 380, 480), the rotatable ring gear (80, 180, 380, 480) having fewer teeth than the fixed ring gear (70, 370, 470) so that rotation of the planetary gears (54, 56, 58) effects a slower rate of rotation of the rotatable ring gear (80, 180, 380, 480). The rotatable ring gear (80, 180, 380, 480) engages a screw (88, 188, 388, 488) which is connected with the piston (30, 130, 330, 430). The piston (30, 330, 430) may be displaced by hydraulic fluid for a service application and the electric motor (40, 340, 440) utilized for a parking application. Alternatively, the piston (130) may be displaced by the electric motor (40) for both service and parking brake applications.
A disc brake that may be operated by motor means, comprising a caliper having a bore with a nut disposed at an end thereof, the caliper and nut actuatable to displace a pair of friction elements into engagement with a rotor, a planetary gear assembly disposed within said bore and comprising a sun gear, planetary gears, and a pair of ring gears, and motor means coupled with said sun gear which drives the planetary gears, one ring gear frictionally engaging the bore of said caliper and the other ring gear rotatable by said planetary gears, the other ring gear engaging nonrotatably screw means which is connected with said nut, operation of said motor means causing rotation of said other ring gear and displacement of said nut into engagement with one of said friction elements so that the caliper, by reaction, displaces the other friction element into engagement with said rotor, the one ring gear having resilient means disposed thereat between the one ring gear and the bore of the caliper, the resilient means effecting in one direction of rotation of the other ring gear a low frictional engagement between said one ring gear and bore and in another direction of rotation of said other ring gear a high frictional engagement between said one ring gear and bore, whereby rotation of said other ring gear in the one direction of rotation may cause the one ring gear to rotate relative to said housing.
Dependencies are inferred from the claim text.