Installation for the unloading of shaft seals in hydrodynamic brakes for vehicles,especially for motor vehicles

Claim 1

A hydrodynamic brake installation comprising: a brake housing, at least one fixed blade wheel and one rotatable blade wheel arranged in spaced facing relationship to one another in said housing, a working fluid circulatory system for supplying working fluid to a working chamber formed between said fixed and rotatable blade wheels to effect braking of a shaft connected to said rotatable blade wheel, a brake actuating member for controlling said supply of working fluid to said working chamber, a shaft seal interposed between said housing and said shaft to limit escape of working fluid from said housing along said shaft, first conduit means for directly communicating the core of said working chamber with a seal space between said housing and said shaft which is sealed off by the shaft seal such that the low pressure experienced at said core during supply of working fluid with a rapidly rotating shaft relieves said shaft seal, pressure responsive brake actuating opposing means connected to said brake actuating member, and second conduit means directly communicating the pressure of said working fluid in said working chamber to said brake actuating opposing means, said brake actuating opposing means including means for automatically opposing the operation of said brake actuating member in response to predetermined high pressures communicated by said second conduit means, whereby an excessive pressure build-up in said seal space resulting from working fluid leakage between said housing and said shaft is automatically limited by the automatic retardation of the operation of said brake actuating member in response to said predetermined high pressures occurring in said working chamber during supply of working fluid with other than a rapidly rotating shaft.