GB1290037A - - Google Patents

Abstract

1290037 Adjusting suspension height USTAV PRO VYZKUM MOTOROVYCH VOZIDEL 26 Nov 1970 [12 Dec 1969] 56315/70 Heading B7D [Also in Division F2] A vehicle suspension system comprises two hydropneumatic piston-cylinder units in free hydraulic communication via a tube 19, one and only one of the units being provided with a pump 12 and asssociated valves 13, 14 for regulating its height, and thereby that of the other unit, and hence that of the vehicle. Each unit is required to have a diaphragm bounded gas chamber 23 acting on a hydraulic chamber 25 which has a passage 21, 22 communicating with the cylinder chamber in front of the piston. The suction valve 13 from the hydraulic chamber 25 and the discharge valve 14 to the cylinder are required to be located in the passage between the chamber 25 and the cylinder chamber. The twin units spring the front and rear axles of the vehicle. In operation when the vehicle is loaded, the piston rods 4, 4<SP>1</SP> rise so that a port 18 in the pump plunger is covered by the piston 5, and liquid is displaced both through damping valves in the piston, and through the tube 19 and passages 22 into the hydraulic chamber 25 of the right hand unit to compress the gas chamber 23. Oscillations of the piston cause liquid to be pumped from the hydraulic chamber 25 of the left hand unit through the valve 13, the pump chamber 24 and the valve 14 and (via the passage 21 or the tube 19) into the cylinder chambers in front of the pistons, causing the units to extend until the port 18 is again uncovered and pumping stops. When the vehicle load is removed, the piston rods fall until a channel 17 in the piston rod 4 co-operates with a passage 16 leading to the hydraulic chamber 25 of the left hand unit. Liquid then flows from the cylinder chamber above the piston through the port 18 and into the hydraulic chamber 25, causing the piston to rise until the connection between passages 17 and 16 is broken.