Patent GB-1029290-A (GB)
Title: Improvements in or relating to suspensions, especially for vehicles
IPC: B60G17/027
Filed: 1962-12-24
Abstract: 1,029,290. Hydraulic shock - absorbers. ROBERT BOSCH G.m.b.H. Dec. 24, 1962 [Dec. 30, 1961], No. 48559/62. Heading F2S. [Also in Division B7] In a suspension system, e.g. for a vehicle, comprising a load-carrying spring and an associated hydraulic piston shock-absorber, a loading device consisting of a fluid-filled pressure chamber transmits the carrying spring load, through a non-return valve, to the working cylinder pressure chamber on the side of the larger surface of the piston in order to prevent cavitation during outward movements of the shock-absorber. As shown in Fig. 1, a suspension spring 4 acts between a chassis 3 and a piston 8 of a loading-pressure chamber 6 which is mounted on a wheel axle 1 and which communicates, through a conduit 10 and a branch conduit 11 controlled by a non-return valve 23, with the lower chamber 19 in the working cylinder 16 of the shock absorber. In a modification, Fig. 2 (not shown), the suspension spring comprises an air spring 25 having a levelregulating connection 27, the hydraulic shockabsorber 31 having a loading-pressure chamber 49 formed by an annular diaphragm 42 connected between a projection 43<SP>1</SP> on axiallymovable base 43 of the shock-absorber and an enlarged portion 41 of a ribbed cylinder 39 which covers the lower half of an outer tube 31 of the shock-absorber, the piston 45 of which works in an inner cylinder 37. The pressure chamber 49 is connected by means of a non- return valve 48, with the working cylinder chamber 46 and through annular spaces 40, 38, connected by ports 51, with the interior side of a piston-rod seal 32 and by means of a non- return valve 50 with the upper working- cylinder space 47. In an alternative arrangement, Fig. 3 (not shown), the inner shell 56 for the rolling-diaphragm of the air spring 58 slidingly receives surfaces 61, 62 of the shockabsorber working-cylinder 59 which is retained by a circlip 60, the surface 61 having a seal 63 and the surface 62 having through ports and serving as a guide. The loading pressure chamber 66 is formed by the annular space between the shell 56 and the cylinder 56. In a further modification, Fig. 4 (not shown), a helical suspension spring 70 is mounted coaxially around the shock-absorber 71 and the upper end of an hydraulic cylinder 72 is slidable within a cover 90 to provide a variable volume pressure chamber 89. In another form, Fig. 5 (not shown), the pressure within an air suspension spring is transferred to the loading- pressure chamber by means of a flexible diaphragm located in a common wall between the air spring and the pressure chamber. Another construction shows a loading-pressure chamber formed by a flexible bellows which acts in series with an air spring containing a parallel-acting coil spring pressure being supplied to the shockabsorber from the loading pressure chamber by means of a valved passage which passes axially through the piston-rod, the loading pressure chamber being located at the upper end of the piston-rod. In a generally similar arrangement, Fig. 7 (not shown), the shock-absorber cylinder is provided with an additional and separate upper chamber which is connected to the passage in the piston-rod. According to Fig. 8, (not shown), the additional chamber 160 has a spring-loaded upper end wall 169, the outside of which communicates through a duct 167 with the air spring so that the additional chamber acts as the loading pressure-chamber. In one form, Fig. 9 (not shown), a pressure chamber 175 is divided by a diaphragm 179 into two compartments which communicate respectively with the interior of an air spring 177 and through ducts 186<SP>1</SP>, 186 with the lower and upper chambers of the shock-absorber 176, the duct 186<SP>1</SP> including branches, the outlets of which are controlled by one-way valves 190, 191. The ducts 186, 186<SP>1</SP> may be replaced by one which passes axially through the piston-rod.