Patent GB-803381-A (GB)
Title: Improvements in or relating to suspension systems
IPC: F16F9/08
Filed: 1955-05-11
Abstract: 803,381. Hydro-pneumatic suspension devices. CITROEN, S. A., A May 11, 1955 [May 12, 1954], No. 13690/55. Class 108(3) The invention relates to a spring suspension comprising a mechanically deformable space connected between the supporting and supported members, and a first chamber containing a fluid, subject to the pressure of a resilient agent or themselves forming a resilient agent, and a damping member controlling the displacements of fluid between the deformable space and the first chamber. According to the invention, a reference cavity contains the mean equilibrium pressure of the agent. The arrangement is such that movements. of the supported member away from its mean position are damped by variations in the pressure of the agent, while return movements are damped as a function of the difference. between the instantaneous pressure of the agent, and the mean pressure of the reference cavity. In Fig. 1, a piston C and cylinder P connected respectively to the supporting and supported members, transmit liquid to a connection 24 with a damping member 3. A connection 34 to the damping member, is connected to a liquid filled chamber B separated by a flexible diaphragm m from a gas filled chamber A. The latter is connected by a pipe having an adjustable constriction a, to a chamber A<SP>1</SP> integral with the damping member 3. The connection 24 of the damping member 3 is connected via an adjustable restriction 31 to a space C' on one side of a double conical valve 8, 9, movable relative to seatings on either side of a chamber 11. The other end of the valve 8. 9, is open through a chamber B<SP>1</SP> in direct communication with the connection 34. A stem 7 of the valve 8, 9 is connected to a resilient sleeve 5 the other side of which is open to pressure in the chamber A<SP>1</SP>. The chamber 11 is also connected with the spaces C<SP>1</SP>, B<SP>1</SP>, by spring loaded ball valve systems 14, and 15, respectively. The space C' is also connected with the connection 24 by a one-way spring-loaded valve 26. In operation, the position of the valve 8, 9, is determined by the differential pressures in the chambers A<SP>1</SP>, B'. The pressure in the chamber A<SP>1</SP> represents the mean of pressures in the chamber A due to the effect of the restriction a. In a modified construction of the damping member III (Fig. 2, not shown), the resilient sleeve 5 is replaced by a flexible diaphragm, the resilience of which is modified by the effect of dished plates between which the diaphragm is sandwiched in its connection to the stem 7. The stem 7<SP>1</SP> at the other end of the valve extends into a further chamber, and is connected to a further flexible diaphragm which divides this chamber into two spaces connected by a passage having an adjustable restriction. This chamber thus functions as a dash pot for movement of the valve 8, 9. In this construction the restriction a is integral with the chamber A<SP>1</SP> In Fig. 3, the suspension is in the form of a single integral assembly. The cavity A<SP>1</SP> is provided by a flexible container 128 within a perforated rigid container 129 within the hollow plunger 114 .of a piston 101 operable within a cylinder 100. The piston 101 and cylinder 100 correspond to the piston P and cylinder C of Fig. 1. A rigid housing 132 connected to the cylinder 100 is divided by a resilient diaphragm 133 into a liquid filled chamber B in perforated communication with the cylinder 100, and a gas-filled chamber A. The valve 8, 9, of Fig. 1, is replaced by a piston valve 108 formed' with ports 109, 110, which connect opposite ends of the valve with ports 105 leading to a space 105<SP>1</SP> corresponding to the chamber 11 of Fig. 1. The space adjacent the upper end of the piston valve 108 is connected to the cylinder 100 by a non-return valve 112 and an adjustable restriction 111. The space adjacent to the lower end of the valve 108 is connected by a restriction 122 to the space above a piston 125 slidable within the hollow plunger 114 of the piston 101. This piston is connected to the stem 121 of the valve 108. A restricted connection 126 leads through the piston to the liquid space adjacent the perforated diaphragm 129. The space 105<SP>1</SP> in the piston 101 is controlled by spring loaded ball valve systems 102, 103, which function in a similar manner to the ball valve systems 15 and 14, of Fig. 1. In Fig. 4, resilience of liquid replaces the use of gas as the resilient medium. The displacement of a piston 151 in a liquid filled cylinder 152 is controlled by the action of a metering rod 154 on compression of the device. On rebound, the metering rod 154 is rendered inoperative by the action of ball valves 156. The equilibrium position of a double coned valve 164 corresponding to the valve 8, 9, of Fig. 1, is controlled by resilient discs 163. The valve 164 is connected to a piston 166 subject to liquid pressure in a chamber 170 corresponding to the chamber A<SP>1</SP> of Fig. 1. Restricted liquid flow can take place around the periphery of the piston 166 and between the rod 165 of this piston and its bearing in the end of the chamber 170. Ball valve systems 168, 167, function similarly to the valve systems 14, 15, of Fig. 1. The whole device is filled with liquid. Resilience of liquid in a chamber 159 connected to the upper end of the valve 164 provides the dual function of the chambers A, B, of Fig. 1. In a modification of Figs. 4 and 5 adapted for hydro-pneumatic operation, the chamber 170 is replaced by a torus-shaped chamber 184 containing an annular gas-filled casing 187. Liquid in the chamber 159 acts on a gas-filled bag 190 corresponding to the chamber A of Fig. 1. The action of the bag 190 may be supplemented by a further gas-filled bag 206 (Fig. 7) disposed on the lower side of the piston 151. The bag 206 is contained in a liquid filled chamber bounded by a housing which has a skirt 216 which co-operates with a depending skirt 217 rigid with the piston 151. The chamber 204 is connected with the space below the piston 151 by an adjust. able restriction 212.