GB1055017A - Hydro-pneumatic spring suspension device especially for motor vehicles - Google Patents

Abstract

1,055,017. Self-levelling hydro-pneumatic suspensions. FICHTEL & SACHS A.G. March 22, 1965 [March 26, 1964], No. 11961/65. Heading F2S. In a self-levelling hydro-pneumatic suspension strut, e.g. for a vehicle when a piston 3 with damping ports 5 moves out of a cylinder 4 and abuts a spring 12 a spring-loaded plate valve 11 is opened and liquid flows from a spring chamber 20 into a reservoir chamber 18 until the piston 3 has again returned into its normal position and no longer rests upon the spring 12. When the piston 3 enters the cylinder 4 sufficiently for the ports 5 in the piston to be closed by a covering piston 6 liquid is sucked past the valve 11 from the reservoir 18 into cylinder 4 so that when the piston 3 descends it pumps liquid through the ports 5 and into the spring chamber 20 the valve 11 being closed. The reservoir 18 is defined by an outer casing 1, the cylinder 4, an end cover 15, and a yieldable wall 10 which is connected by a rigid sleeve 9 with a yieldable wall 8 which closes the lower end of the spring chamber 20 which is formed within the upper end of the casing 1 openings 19 being provided in the upper end of the cylinder 4. The space between the walls 8, 10 is open to atmosphere through a port 21, the walls 8, 10 acting as a differential piston so that the pressure in the reservoir 18 is always less than that in the spring chamber 20 which has a gas filling 36 for supplying the spring work. In a modification, Fig. 2, not shown, in addition to the spring chamber 120 and the reservoir 118 there is provided a high pressure accumulator 123 within a hollow piston rod 122. When the piston 103 descends to abut a spring 129 to open the plate valve 111 and to bridge longitudinal grooves 129 in the inside wall of the cylinder 104 fluid flows from the spring chamber 120 into the reservoir 118 to relieve the pressure within the chamber 120 so that the piston 103 can return to its normal position out of contact with the spring 129. If the piston 103 enters the cylinder 104 enough for a valve plunger 128 with a groove 132 to contact a stop plate 127 then fluid flows from the high pressure accumulator 123 into the chamber 120 until the piston 103 is pushed back within its normal working range. Small oscillations of the piston 103 without the valve plunger 128 or the piston 103 coming into contact respectively with the plate 127 or the spring 129 pumps liquid from the reservoir 118 through a port 131 in the piston rod and past a resilient valve ring 130 into the high pressure accumulator 123 until the yieldable wall 110 comes into contact with a stop ring 126 whereupon no more liquid can be drawn from the reservoir 118. In a further modification. Fig. 3, not shown, which operates in a manner generally similar to the embodiment of Fig. 2, the yieldable walls are located so as to be responsive to pressure in the reservoir and the high pressure accumulator.