Hydraulic damper with adjustable rebound valve assembly

Abstract

The present invention relates to a hydraulic damper (1), in particular a motor vehicle suspension damper (1), comprising at least one tube (2) filled with working liquid, inside of which a slidable piston assembly (3) attached to a piston rod led outside the damper through a sealed rod guide (5) and provided with rebound (9) and compression (10) valve assemblies to control the flow of working liquid passing through the piston assembly (3) during rebound and compression stroke of the damper, is disposed dividing the tube into a compression chamber (8) and a rebound chamber (7), wherein the piston assembly comprises a body (31 ) fixed to the piston rod and provided with at least one passage (311) to allow free flow of working liquid between the rebound chamber (7) and an internal chamber (313) in said piston body, an orifice plate (33) provided with through rebound flow means, rebound valve means which cover the compression side of said through rebound flow means, a cage member (34) fixed to the piston assembly at the compression side thereof and provided with at least one passage (341, 343) to allow free flow of working liquid between the compression chamber (8) and an internal chamber (344) of said cage member, and a compression spring (95) preloaded between the compression side of said cage member (34) and said rebound valve means acting on said rebound valve means to normally close said compression side of said through rebound flow means. In order to improve the operational characteristic of dampers within a production batch, as well as within the same operating conditions, as well as to improve the damper tuning options said orifice plate (33) is further provided with an axial projection (334) and said through rebound flow means have a form of a number of rebound flow passages (332) disposed around said projection (334), and in that said rebound valve means comprise a deflectable disc (91) and an elliptical disc (92) disposed slidably one on top of the other over said axial projection (334).

Description

technical field [0001] The present invention relates to a hydraulic damper, in particular to a motor vehicle suspension damper, comprising at least one tube filled with working fluid, a piston assembly capable of sliding is arranged inside the tube to divide the tube into a compression chamber and a rebound chamber. chamber, the piston assembly is connected to the piston rod which is guided to the outside of the damper through the seal rod guide, and has a rebound valve assembly and a compression valve assembly to control the working fluid during the rebound stroke and compression stroke of the damper Flow through the piston assembly, wherein the piston assembly includes: a body fixed to the piston rod and provided with at least one passage for the free flow of working fluid between the rebound chamber and the inner chamber in the piston body an orifice plate provided with a rebound flow device and a rebound valve device covering the compression side of the rebound flow device...

AI Technical Summary

Problems solved by technology

However, in this type of deflate rebound valve assembly, where the centrally located generally rigid disc is preloaded by a compression spring, such a Relatively low repeatability of the opening torque of the rebound valve assembly, leading to uncertainty in the position of the knee point and unpredictable deviations of the observed force-velocity characteristics from the theoretical ones

Furthermore, in prior art dampers as described above, only the inclination and position of the inflection point of the second part of the characteristic can be adjusted by proper choice of compression spring stiffness and preload

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