GB792287A - Improved liquid cooled friction brake - Google Patents

Abstract

792,287. Cooling brakes. GENERAL MOTORS CORPORATION. Aug. 2, 1956 [Aug. 23, 1955; Oct. 19, 1955; Nov. 30, 1955], No. 23927/56. Class 103 (1). In a liquid-cooled friction brake, cooling liquid is circulated, under pressure by a pump, between stationary and rotatable annular friction brake members 62 and 63 respectively, which are connected to a housing 18 and axle 30 respectively; the pump 41 being located in a central cavity 40 of the housing and adapted to be driven by the axle and friction members being adapted to be engaged by an annular piston 85 slidable in a fluidpressure chamber 90 in the housing around the central pump cavity. Figs. 1, 3 and 4 illustrate various sections through a brake and the operation is such that the eccentric vane type pump 41 draws fluid from inlet passage 96 leading from heat-exchanger through space 170 and inlet holes 175 (Fig. 3) in the closure wall 100, and delivers fluid under pressure through ports 48 (Fig. 3) to compartment 93 whence it passes through grooved passages in the faces of the friction brake members 62, 63 to compartment 94. Fluid under pressure is also delivered through recess 166 (Fig. 4), passage 167, grooves 168, 169 and 49 to passage 47a leading back to inlet space 170. This latter internal flow of cooling fluid takes place until the temperature of the coolant reaches a predetermined minimum value. If the temperature of the fluid is raised above this value by its passage through the friction brake members, a thermally responsive device 180 expands to move a valve 160 to close off groove 49 from groove 168 and lift valve face 165 from its seat to allow the pressure of fluid delivered by the pump to increase by closing the outlet from the inlet and direct fluid through passage 164 and recess 163 to passage 95 where it passes through the heat exchanger to inlet passage 96. Manual operation of the brake may be effected by movement of operating cable 136 which moves the lever 225 about fulcrum pin 129 to actuate two links 132 and actuate two piston plungers 221 slidable in bores 220 in housing 18 to effect engagement with annular piston 85. Manual adjustment of the clearance between the friction brake members 62 and 63 when the brake is in the released condition is regulated by an adjustment screw 140 (Fig. 3) threaded in bore 141 in housing 18. Further embodiments are described and illustrated in the Specification in which the friction brake is associated with an axle housing extending from the differential housing of the motor vehicle; the operation of the brake being similar to that disclosed above but provision being made for the inclusion of an additional device to prevent seepage of fluid from the chamber housing the friction brake members to the annular chamber housing the fluid pressure brake applying piston.