Patent ID: 9657803
Date: 2017-05-23
CPC Classifications: B21D,F16F

Claim:
1. A hydraulic damper comprising a tube filled with working liquid, a main piston assembly disposed slidably inside the main section of the tube, attached to a piston rod led outside the damper and dividing the tube into a rebound chamber and a compression chamber, rebound and compression valve assemblies to control the flow of working liquid within the tube during a rebound and compression stroke of the damper, wherein at least one end of the tube is provided with a narrower section of a smaller diameter provided at least partially with at least one axial groove and the damper is further provided with at least one additional piston assembly having a diameter smaller than a diameter of the main section of the tube, displaceable along with the main piston assembly and apt to be introduced in said narrower section of the tube to generate additional damping force; said narrower section extends through a conical section into the main section of the tube and said conical section is internally shaped to form a plurality of axial bridges extending radially inwardly and defining said at least one axial groove between said axial bridges, and wherein said at least one axial groove extends along the length of said conical section, each of said axial bridges comprising a cylindrical section, a conical section and a transitional section between said cylindrical and conical sections, wherein said cylindrical sections of said axial bridges define a semi-cylindrical section of said tube to provide guidance for said at least one additional piston assembly, and said conical sections of said axial bridges define a semi-conical section of said tube; said at least one groove having a lower portion extending along the same axial length as said cylindrical sections of said axial bridges, a middle portion extending along the same axial length as said transitional sections of said axial bridges, and an upper portion extending along the same axial length as said conical sections of said bridges; and the width of said lower portion of said at least one groove between said axial bridges tapering inwardly along the length of said lower portion toward said middle portion, and the width of said upper portion of said at least one groove between said axial bridges tapering inwardly along the length of said upper portion toward said middle portion.