Hydraulic damper with a hydraulic stop arrangement

Patent metadata

Field	Value
Publication number	US-10174802-B2
Application number	US-201715487370-A
Country	US
Kind code	B2
Filing date	Apr 13, 2017
Priority date	May 11, 2016
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

A hydraulic damper including a tube defining a chamber. The tube has a main section and a narrowed section. A main piston assembly is disposed in the main section and connected to a piston rod. A resisting mechanism is fixed to the piston rod. A secondary piston is moveable into the narrowed section. An inner surface of the secondary piston defines at least one radially internal channel. The piston rod defines an annular recess. The secondary piston includes a locking mechanism axially slideable within the annular recess. The secondary piston is axially moveable between a hydraulic stop engagement stroke wherein the secondary piston engages the resisting mechanism and restricts the flow of fluid through the radially internal channel, and a hydraulic stop disengagement stroke wherein the secondary piston is spaced from the resisting mechanism and allows the flow of fluid through radially internal channel.

First claim

What is claimed is:

1. A hydraulic damper for a motor vehicle comprising:
a tube extending along an axis and defining a chamber for holding a fluid;
said tube having a main section having a first diameter and a narrowed section having a second diameter being smaller than said first diameter;
a main piston assembly disposed in said main section of said tube and axially slideable within said main section of said tube to generate a damping force;
a piston rod attached to said main piston assembly and extending axially outside of said tube;
a resisting mechanism disposed about and fixed to said piston rod;
a secondary piston disposed about said piston rod on the axially opposite side of said resisting mechanism as said main piston assembly and having an external diameter substantially corresponding to said second diameter of said narrowed section of said tube and axially displaceable with said main piston assembly and moveable into said narrowed section of said tube to generate an additional damping force;
said secondary piston defining a radially inner surface engaging said piston rod and a radially outer surface opposite said radially inner surface;
said radially inner surface defining at least one radially internal channel extending axially;
said piston rod defining an annular recess at least partially in axial alignment with said secondary piston; and
said secondary piston including at least one locking mechanism positioned in said annular recess of said piston rod and axially slideable within said annular recess;
wherein said secondary piston is axially moveable between a hydraulic stop engagement stroke and a hydraulic stop disengagement stroke, wherein said secondary piston axially engages said resisting mechanism and restricts the flow of working fluid through said at least one radially internal channel during said hydraulic stop engagement stroke, and wherein said secondary piston is axially spaced from said resisting mechanism and defines an annular channel between said piston rod and said secondary piston opening flow of working fluid through said at least one internal channel during said hydraulic stop disengagement stroke, wherein said radially outer surface of said secondary piston defines a plurality of radially external channels each extending axially.

2. A hydraulic damper as set forth in claim 1 , wherein a cross-sectional surface of said radially external channels of said secondary piston in a plane perpendicular to said axis is the largest at its face opposite to the resisting mechanism and decreases along the axial length of said secondary piston.

3. A hydraulic damper as set forth in claim 1 , wherein said locking mechanism of said secondary piston includes a plurality of radially internal elastic hooks.

4. A hydraulic damper as set forth in claim 3 , wherein a plurality of radially internal bridges extending axially are defined between said radially internal channels, wherein each of said axially extending bridges terminates axially at one of said hooks, and wherein said secondary piston defines a chamber about said hooks.

5. A hydraulic damper as set forth in claim 3 , wherein each of said hooks includes a flat surface extending perpendicular to said axis and a conical surface extending at an angle relative to said flat surface.

6. A hydraulic damper as set forth in claim 1 , wherein an end of said secondary piston defines a convex guiding surface.

7. A hydraulic damper as set forth in claim 1 , wherein said secondary piston is of a plastic material.

8. A hydraulic damper as set forth in claim 1 , wherein said resisting mechanism is a retaining ring being fixed in said annular recess of said piston rod.

9. A hydraulic damper as set forth in claim 1 , further including at least one spring disposed in said narrowed section of said tube for axially engaging said secondary piston to generate an additional damping force.

10. A hydraulic damper as set forth in claim 1 , further including at least one bumper in said narrowed section of said tube for axially engaging said secondary piston to generate an additional damping force.

11. A hydraulic damper as set forth in claim 1 , wherein said tube extends axially between a compression end and a rebound end, and wherein said narrowed section is located at said rebound end of said tube.

12. A hydraulic damper as set forth in claim 1 , wherein said damper assembly is a twin-tube damper.

13. A hydraulic damper as set forth in claim 1 , wherein at least one axial slot is defined in said narrowed section of said tube.

Assignees

• Beijingwest Ind Co Ltd

Inventors

• Osika Miroslaw Pawel
• Pilawski Karol Jakub
• Schab Jakub Pawel

Classifications

• B60G13/08

  hydraulic · CPC title

• F16F9/3235

  of cylinders (F16F9/483 takes precedence) · CPC title

• F16F2222/12

  Fluid damping · CPC title

• B60G15/06

  and fluid damper · CPC title

• F16F13/007

  the damper being a fluid damper · CPC title