Hydraulic damper with a hydraulic compression stop assembly
The present disclosure relates to a hydraulic damper comprising a main tube, a piston assembly, a base valve assembly, and at least one hydraulic compression stop assembly cooperating with a compression valve assembly, and comprising a pin disposed slidably within the piston rod and biased to project an activating tip towards the compression chamber. Said compression valve assembly comprises at least one deflectable or floating disc covering compression flow passages, and biased by a piston member slidable along said axis and normally abutting a retaining surface, and a pressure chamber having one surface defined by a surface of said piston member abutting said retaining surface, wherein said pin upon sliding inside the piston rod facilitates a flow of the working liquid from the compression chamber into said pressure chamber to increase biasing load on said at least one deflectable or floating disc.
1. A hydraulic damper, comprising:
a main tube filled with working liquid and extending along an axis between an open end and a closed end;
a piston assembly slidably disposed inside the main tube, attached to a piston rod that extends outside the hydraulic damper through a sealed piston rod guide located at the open end, dividing the main tube into a rebound chamber and a compression chamber and configured to generate a damping force;
a base valve assembly located at the closed end of the compression chamber and configured to control a flow of the working liquid between the compression chamber and a compensation chamber; and
at least one compression stop assembly cooperating with a compression valve assembly and comprising a pin disposed slidably within the piston rod and biased to project an activating tip towards the compression chamber to increase damping of said compression valve assembly upon sliding inside the piston rod and to generate an additional damping force with said piston assembly at an end of a compression stroke;
wherein said compression valve assembly comprises:
at least one deflectable or floating disc covering compression flow passages and biased by a piston member slidable along said axis and abutting a retaining surface, and
a pressure chamber having one surface defined by a surface of said piston member abutting said retaining surface; and
wherein said pin, upon sliding inside the piston rod, facilitates a flow of the working liquid from the compression chamber into said pressure chamber to generate a pressure on said surface of said piston member to increase a biasing load on said at least one deflectable or floating disc.
2. The hydraulic damper according to claim 1 , wherein the piston assembly includes compression and rebound valve assemblies to control the flow of working liquid passing between the rebound chamber and the compression chamber to generate the damping force.
3. The hydraulic damper according to claim 1 , wherein said compression valve assembly comprises at least one spring having a first surface biasing said at least one deflectable or floating disc, and a second surface biasing said piston member.
4. The hydraulic damper according to claim 1 , wherein said compression valve assembly cooperating with said at least one compression stop assembly includes a compression valve assembly of the piston assembly, and said pressure chamber is additionally defined by a guiding portion fixed on the piston rod,
wherein the piston rod has at least one radial channel in fluid communication with said pressure chamber and normally disconnected from the compression chamber by a wall of the pin,
wherein the pin has at least one axial channel in fluid communication with the compression chamber having an outlet distal to the activating tip of the pin normally closed by the wall of the piston rod,
wherein said compression flow passages are disposed within the piston assembly, and
wherein upon sliding of the pin inside the piston rod along a predetermined distance said at least one axial channel of the pin is in fluid communication with said at least one radial channel of the piston rod to generate pressure on said surface of said piston member.
5. The hydraulic damper according to claim 4 , wherein said at least one axial channel has a form of a narrowed cross-section of said pin.
6. The hydraulic damper according to claim 1 , wherein said compression valve assembly cooperating with said at least one compression stop assembly is installed within an adapter disposed between the base valve assembly and the compression chamber and comprising an axial opening for a flow of the working liquid through the base valve assembly between the compression chamber and the compensation chamber which is closable by the activating tip of the pin, and said pressure chamber is additionally defined by a guiding portion of said adapter, wherein the adapter has at least one radial channel in fluid communication with said pressure chamber and normally connected with the compression chamber,
wherein said compression flow passages are disposed within a valve member fixed between said adapter and the main tube,
wherein closing said axial opening by the activating tip and sliding of the pin inside the piston rod along a predetermined distance generates pressure on said surface of said piston member.
7. The hydraulic damper according to claim 6 , wherein said adapter comprises a number of axial flow passages surrounding said guiding portion, and said valve member has a number of rebound flow passages covered in the compression chamber by at least one deflective or floating intake disk provided with a number of flow passages that allow the working liquid to flow to said compression flow passages during the compression stroke of the hydraulic damper.
8. The hydraulic damper according to claim 1 , wherein the pin is biased by a spring disposed within an internal chamber in the piston rod.
9. The hydraulic damper according to claim 8 , wherein the pin has an internal axial channel joining the compression chamber with said internal chamber in the piston rod.
10. The hydraulic damper according to claim 1 , wherein the hydraulic damper is a motor vehicle suspension damper.