Liquid cooled brake unit

An improved brake unit adapted to be mounted on a motor for quickly stopping the rotation of a shaft projecting from the motor, said brake unit comprising a hub member having a center bore for receiving the shaft and including an annular portion projecting axially from a mounting portion adapted to engage the shaft to define a liquid coolant inlet, means for rigidly securing said hub member to the shaft, a plurality of annular brake discs mounted on said annular portion of said hub member for rotation therewith and for axial movement relative to said hub member, said annular portion of said hub member having circumferentially spaced and generally radially extending passages connecting said inlet to the inner portions of said brake discs, a housing surrounding said hub member and including an annular base section coupled to a closure section by an annular intermediate section, means connected to said intermediate section of said housing and supporting a plurality of non-rotatable annular brake plates disposed between said brake discs in interfitting relation, fastener means for securing said base section of said housing to the motor, a liquid coolant within said housing, said coolant being forced outwardly from said inlet through said passages and between said brake discs and plates in response to rotation of said hub member and said brake discs, an annular non-rotating piston supported by said intermediate section of said housing for axial movement relative to said hub member, means for moving said piston axially to effect axial compression and release of said brake discs and plates, means defining passages within said housing for recirculating said coolant from the periphery of said brake discs and plates to said inlet of said hub member, and said closure section of said housing including a portion spaced axially from the shaft and opposing said inlet.