Patent GB-1135212-A (GB)
Title: Wheel suspension
IPC: B60G17/005
Filed: 1965-12-09
Abstract: 1,135,212. Vehicle suspensions. K. H. SCHMIDT. 9 Dec., 1965 [9 Dec., 1964], No. 52364/65. Heading B7D. In a motor vehicle suspension system, a suspension unit, which may be associated with a single wheel, or a pair of wheels, or with one end of a beam axle, comprises a piston and cylinder unit having a large diameter pistonrod, the spaces on opposite sides of the piston being connected together and units on one side of the vehicle, or diagonally opposite units being hydraulically connected together. The arrangement is such that a change of suspension height of one unit, e.g. due to a road shock, causes change of suspension height of the associated unit owing to transfer of liquid due to the difference in volumes in the cylinder spaces on opposite sides of each piston. The fluid lines may be connected through changeover and stop valve units to a fluid pump and reservoir. In the motor vehicle suspension shown in Fig. 1, each axle 7 or 8 associated with a wheel pair 5 or 6 is connected to a suspension unit 9 comprising an hydraulic piston and cylinder wherein the piston-rod is of large diameter. The cylinder spaces on opposite sides of the piston in each unit are interconnected by a line 12 and the units are interconnected in pairs by the lines 15a, 15b, 16a, 16b, 17a, 17b, 18a and 18b, and the pairs interconnected by the lines 15, 17, and 16, 18, as shown, with further connections being made through lines 21 and 22 to valves 23 and 24 which are connected to a pump 26 and to a fluid reservoir 28. Valves 19, which have throttled connecting and isolating positions, are provided in the lines 15, 16, 17 and 18. In operation, if the load on one unit 9 changes so that the piston moves, fluid is either forced out or accepted into that unit according to the direction in which the piston moves (owing to the difference in volume between the spaces on the opposite sides of the piston) with a consequential action on an associated unit, or the action may take place between pairs of units if the valves 19 are in connecting positions. The valves 23 and 24 are actuated to raise or lower the vehicle height which may be uniform, or by selective operation of the valves 23, 24 and 19 at one suspension only, one side or one end only of the vehicle. In a modification (Fig. 2, not shown), a wheel pair at each corner of the vehicle is suspended by a unit which is hydraulically interconnected in a similar system with the unit diagonally opposite. In a further modification, Fig. 3, the wheels 205, 206 are mounted on solid axles and the line 12 connecting the cylinder spaces on opposite sides of each piston is provided with a valve 32 and also upper and lower lines 15, 17 and 33, 35; 16, 18 and 34, 36 connect the units, as shown, with shut off valves 19 and 49 being provided in the lines 17, 18, 33, 34, respectively. Threepositior control valves 223 and 224 are provided and have lines 21, 37 and 22, 28 connecting with the fluid lines interconnecting the suspension units. If a valve 19 or 49 together with a valve 32 is closed, the associated fluid suspension unit is fluid-locked. By selective operation of the valves 19, 49, 32, 223 and 224 the height of a single wheel, or a pair of wheels on one side or at one end may be varied and with the valves 223 and 224 in the position I, the other valves being opened, there is an interaction between the suspension units on each side of the vehicle. Flow restricting orifices to damp the vibrations are provided in the valves 19 and 49. In a further modification (Fig. 4, not shown) the suspensions of diagonally opposite wheels of the system of Fig. 3 are connected for interaction, the raising of one or any pair of wheels again being by selective actuation of the valves. In Fig. 5 (not shown), the device of Fig. 3 is modified by the inclusion of a hydropneumatic spring element at each suspension unit, the valve 32 being modified to provide a parallel connection to the spring element in its open position (valve 232). Alternatively, a single hydropneumatic spring may be acted upon by all four suspension units. The connections to the air spring include a throttling device, bypassed by a one-way valve, to provide for damping in one direction only. An arrangement for diagonal cross connection of the suspension units corresponding to Fig. 5 is described with reference to Fig. 6 (not shown). In Fig. 7, constructional details are shown in a system similar to Fig. 5 but in which the upper cylinder spaces 13 are permanently connected without the interposition of a valve, and valves 249 are provided in lines 35 and 36. Throttling orifices 220 and 250 are provided and a common line 44 is provided for actuating the valves 232, corresponding to the valves 32 and another, 45 for operating the valves 249. Alternatively, separate lines for the actuation of the valves may be provided and each valve 223, 224 may be replaced by two separate " three-way " valves. In Figs. 10, 11, 12 and 13 (not shown) constructional embodiments of the suspension units and valves corresponding to the valves 19, 32, 41 are given in which the valves are actuated hydraulically or pneumatically, electrically and through a Bowden cable and linkwork mechanism. In Fig. 11, the valves 32 and 48 are replaced by pairs of valves (32a, 32b and 48a, 48b) in series and it is possible, in these embodiments to open the line 12 before connecting to the hydropneumatic unit 40. Any valve in the system may be operated by the hydraulic, pneumatic, mechanical and electrical methods described.