GB668926A - Hydraulically damped spring suspension devices - Google Patents

Abstract

668,926. Hydraulic shock-absorbers. SERSTE, J. E., TEPLOW, J., SERSTE, P., and SERSTE, P. Jan. 16, 1950 [Jan. 21, 1949], No. 1082/50. Classes 108(ii) and 108(iii) An hydraulic damping device comprises three main elements of tubular and/or cylindrical shape two of which are actuated by the impulses to be damped and the other of which is free from any mechanical attachment, the elements being disposed concentrically whilst maintaining unchanged under displacement the distances between opposed surfaces, and being guided by annular parts, each of which also serves as a transverse wall between the concentric surfaces of the elements guided thereby in order to form two series of cells, the first series for employment as the braking resistance and' the second series for use in automatically regulating the operation of the other, the mechanically free member remaining hydraulically suspended between the two controlled elements. In the construction shown in Fig. 1, cylinders 1 are rigid with the sprung mass of the vehicle and with a rod 2 which rigidly carries a piston 3. A cylinder 4 is slidable relative to the piston 3 and rod 2 and is slidably mounted within a cylinder 7 rigid with the unsprung mass 14. Suspension is provided by springs 11, 12. The cylinder 7 may rotate about the axis of the rod 2, to provide steering movements. A spring 19 normally maintains the cylinder 4 in the position shown, relative to the piston 3. Grooves 10 which taper towards each extremity, are formed in the outer surface of the cylinder 7 and co-operate with an inwardly-projacting annular portion 8 of the cylinder 7, to provide a damping action to flow between the two liquid chambers 9, 9<SP>1</SP>, formed in the cylinder 7 by the existence of the cylinder 4. A clearance 6 is provided for flow between the damping chamber 5, 5<SP>1</SP> formed in the cylinder 4 by the piston 3. Orifices 6<SP>1</SP> respectively connect the chambers 5, 5<SP>1</SP> with the chambers 9, 9'. Liquid which collects at 16 in the cylinder 1<SP>1</SP> is pumped up through a passage 17 in the rod 2 to pass into a reservoir 15 within the cylinder 1 from whence it can pass via a non-return valve 18 into the chamber 9. In the construction shown in Fig. 3, upper and lower sets of grooves 10, 10<SP>1</SP> co-operate with respective annular portions 8, 8' rigid with the cylinder 7. In the construction shown in Fig. 4, the rod 2 and piston 3 are rigid with the unsprung mass and the cylinder 7 is rigid with the sprung mass. The ballvalve 18 is replaced by a duct 18<SP>1</SP> extending from the interior to the exterior of the cylinder 7. The rod 2 is coupled by upper and lower links 23, 24 to respective links 21, 22 carrying the axle assembly. Either or both of the pivots 25, 26 of the links 21. 22 may be connected to a respective torsion bar which may be instead of, or additional to, the spring 11. Liquid which escapes to the outer cylinder may be returned by a pump 27. The portion of the rod 2 below the piston 3 is of smaller diameter than that of the portion above. In a simple modification of the last construction Fig. 5 (not shown), only one of the liks 23, 24 is provided and this is in direct engagement with the piston 3, the rod 2 being dispensed with. The grooves 6 in the cylinder 4 in this construction may be of varying length.