초록 ▼

A pressure modulated hydrodynamic retarder is provided for a power delivery system and speed sensing means is provided for sensing the rotational speed of the output of the retarder for producing a corresponding pressure fluid flow which acts to vary the fluid relief pressure of a pressure control v

A pressure modulated hydrodynamic retarder is provided for a power delivery system and speed sensing means is provided for sensing the rotational speed of the output of the retarder for producing a corresponding pressure fluid flow which acts to vary the fluid relief pressure of a pressure control valve for the retarder and consequently varies the torque of the retarder in accordance with its rotor speed. In this manner the retarder is modulated as determined by its output speed and when the invention is used in a hoisting operation, as the lowering speed increases due to the falling load the retarding action of the retarder also increases. A particularly desirable form of sensing means includes a variable flow fluid pump which is driven at a speed proportional to the lowering speed of the load to proportionately vary the retarding ability of the retarder. The retarder system may include a one-way clutch between the retarder rotor and the power output shaft to provide for free-wheeling of the retarder when the shaft is rotated to raise the load, and which one-way clutch connects the rotor to the shaft when the shaft is rotating in the opposite direction to lower the load and this arrangement permits raising of the load without interference from the retarder and then automatically connects the retarder to the shaft when the load is lowered.

대표청구항 ▼

A power delivery system comprising a pressurized fluid circuit, a fluid pressurized and modulatable hydrodynamic retarder having a rotor drivingly connected to a power output shaft, said retarder having a pressure fluid inlet and a pressure fluid outlet in said circuit, a retarder outlet pressure co

A power delivery system comprising a pressurized fluid circuit, a fluid pressurized and modulatable hydrodynamic retarder having a rotor drivingly connected to a power output shaft, said retarder having a pressure fluid inlet and a pressure fluid outlet in said circuit, a retarder outlet pressure control valve in said circuit, speed sensing means for sensing the rotational speed of said output shaft and for producing a corresponding pilot signal acting upon the retarder outlet pressure control valve, including means to infinitely modulate the fluid relief pressure of said valve as a predetermined and selectively variable function of rotor speed to thereby modulate the torque of said retarder in accordance with a predetermined desired torque-speed relationship.