Autoipari Kutato Intezet

Autoipari Kutato Es Fejleszto Vallalat

Istvan Szarka

Janos Urbantsok

A hydro-pneumatic operating device for motor vehicle clutches permits shifting into second or higher gears without operation of the clutch pedal, by manipulation of an electric switch that actuates an electro-pneumatic valve. A cylinder block 31 is provided that houses a hydraulic working cylinder having a hydraulic piston of a hydro-pneumatic piston, and a pneumatic servo-valve unit whose path control is actuated by an external operating element which cooperates with a pneumatic servo-piston (14) of the hydro-pneumatic piston (20). On an end face of the pneumatic servo-piston (14) opposite a pneumatic servo-chamber (11) there is a supporting surface 19 whose countersurface 118 is formed on the pneumatic servo-piston (20a) of the hydro-pneumatic piston 20. The other side of pneumatic servo-piston 20a confines a blow-off chamber 22. A cylinder section 13 of a pneumatic working chamber 15 enclosed by the hydraulic pneumatic piston 20 and the pneumatic servo-piston 14 has a connection 66 for pressure medium. The hydro-pneumatic piston 20 has a duct 46 leading to blow-off chamber 22, which chamber 22 has a blow-off unit 47 discharging to the free atmosphere. An axial bore 51 leading to duct 46 has a shaft 50 with a longitudinal through channel 49 communicating with a blow-off chamber 119 of the path controlling servo-valve unit.

Hydro-pneumatic operating device actuated with a pneumatic

Controlling and operating device for motor-vehicle friction clutches between the engine and a manual change-speed gear, comprising a manually operated electric switch actuated with the gear-shift lever of the vehicle; a limit switch allowing the device to be rendered inoperative; a release mechanism operated by the clutch pedal; a hydro-pneumatic release unit including two coupled working cylinders of which respective pressure spaces are connected via duct elements to a cylinder of the clutch and via an electro-pneumatic valve to a source of a pressure medium; in its rest position the valve prevents communication between the source and the space of one of the cylinders and provides a different communication from the space of that cylinder to a retarding blow-off unit that forms part of the inventive device and communicates with the free atmosphere, while when the valve is in its operative position it opens the first-named communication and prevents the other; and an electrical circuit that serially connects the electric switch and the limit switch between an electric power source and an operating electromagnet of the valve. Three exemplary embodiments of the blow-off unit are disclosed.

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Budapest, Hungary

Istvan Szarka