Damping assembly, in particular for a flap of a vehicle

Patent metadata

Field	Value
Publication number	US-9920563-B2
Application number	US-201615006548-A
Country	US
Kind code	B2
Filing date	Jan 26, 2016
Priority date	Jan 28, 2015
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

A damping unit includes a cylinder which is filled with a damping fluid and in which a piston rod is guided, the piston rod associated with a bottom surface which has at least one axial through-hole which defines an effective flow cross section for the damping fluid; wherein the piston rod includes: a sleeve element which is fixed on the piston rod in the axial direction; a piston bottom element which is supported on the piston rod so as to be axially slidable and includes the bottom surface; a resilient element; and a termination element which is fixed on the piston rod in the axial direction and forms an indirect or direct stop for the piston bottom element in the insertion direction of the piston rod.

First claim

The invention claimed is:

1. Damping unit comprising:
a cylinder which is filled with a damping fluid and in which a piston rod is guided in an axial direction of the cylinder so as to be able to be inserted and withdrawn, the piston rod being associated with a bottom surface which extends between the piston rod and an inside wall of the cylinder and has at least one axial through-hole which defines an effective flow cross section for the damping fluid;
wherein the piston rod comprises, at the front end thereof in the insertion direction into the cylinder:
a stop which is fixed on the piston rod in the axial direction and defines a front face in the insertion direction of the piston rod;
a piston bottom element which is supported on the piston rod so as to be axially slidable and comprises the bottom surface;
a resilient element which prestresses the piston bottom element relative to the piston rod in such a way that, in an idle state of the piston rod, the bottom surface of the piston bottom element and the front face of the stop are spaced apart from each other by means of the effect of the resilient element; and
the resilient element being designed such that, above a predefined insertion speed of the piston rod into the cylinder, the dynamic pressure of the damping fluid causes the bottom surface of the piston bottom element to come into contact with the front face of the stop against the effect of the resilient element, and the effective flow cross section for the damping fluid being reduced due to the interaction of the front face of the stop and the at least one axial through-hole in the bottom surface of the piston bottom element,

wherein the piston bottom element is associated with a sealing element which produces a seal between the piston bottom element and the inside wall of the cylinder, and further wherein the sealing element is formed separately from the piston bottom element and is received between the piston bottom element and a retaining element, the retaining element being slidably supported on the piston rod and comprising at least one axial through-hole.

2. Damping unit according to claim 1 , wherein the stop is formed by a sleeve element which has a casing which extends substantially in the axial direction, is spaced apart from the piston rod, and is open in the insertion direction of the piston rod, such that a chamber is formed between the piston rod and the casing, and the front face of the stop being defined on the open end of the casing in the insertion direction of the piston rod, the resilient element being received in the chamber formed between the piston rod and the sleeve element at least in part so as to be supported on the sleeve element at one end and on the piston bottom element at the other end.

3. Damping unit according to claim 1 , wherein a termination element is provided which is fixed on the piston rod in the axial direction and forms an indirect or direct stop for the piston bottom element in the insertion direction of the piston rod.

4. Damping unit according to claim 1 , wherein the piston rod has a region having a reduced circumference in the axial region thereof between the termination element and the sleeve element.

5. Damping unit according to claim 1 , wherein the termination element is formed by a nut which is screwed onto the piston rod.

6. Damping unit according to claim 1 ,
wherein
the cylinder comprises an axial portion in which the inside wall of the cylinder has an entirely concave cross sectional shape formed of a plurality of outwardly curved edges alternatively connected by rounded corners.

7. Damping unit according to claim 6 , wherein the piston has a substantially circular periphery when viewed axially, the periphery of the piston substantially corresponding to an inscribed circle of the cross sectional shape of the inside wall of the cylinder.

8. Damping unit according to claim 7 , wherein the cylinder also comprises further axial portion in which the inside wall of the cylinder has a circular cross section having substantially the same periphery as the piston.

9. Damping unit according to claim 6 , wherein the cross sectional shape of the inside wall of the cylinder has three rounded corners.

10. Damping assembly for a flap of a motor vehicle, comprising a damping unit according to claim 1 , wherein the damping assembly has a first damping force at a closure speed of the flap below a predetermined threshold value and has a second damping force at a closure speed above the threshold value, which second damping force is greater than the first damping force.

11. Damping assembly according to claim 10 , wherein the damping assembly has a third damping force in the case of a closure movement after a predetermined closure path, which third damping force is smaller than the first and the second damping force.

12. Damping assembly according to claim 10 , wherein the piston rod has a flap stop at the end thereof opposite the piston bottom element, which stop is designed to come into contact with the flap during the closure movement of the flap, such that the flap transmits an axial force to the flap stop in an insertion direction of the piston rod into the cylinder.

13. Flap assembly comprising a frame of a motor vehicle, a flap which is attached to the frame so as to be movable between an open position and a closed position, and a damping assembly according to claim 12 , the cylinder of which is fastened or intended to be fastened to the frame or to the flap, wherein the flap can be moved from the open position over a first partial path region in a manner substantially uncoupled from the damping assembly until the flap strikes the flap stop, and in that the flap can subsequently be moved over a second partial path region into the closed position and pushes the piston rod into the cylinder in the process.

14. Damping unit according to claim 1 , wherein the sealing element has a rectangular cross section.

Assignees

• Stabilus Gmbh

Inventors

• Löhken Lars
• Probst Ulrich
• Hewel Michael

Classifications

• F16F9/3235

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

• F16F9/512

  Means responsive to load action, {i.e. static load} on the damper or {dynamic} fluid pressure {changes} in the damper, {e.g. due to changes in velocity (F16F9/504, F16F9/516 take precedence; non-automatic damper adjustment from a distance using servo control, the servo pressure being created by the flow of damping fluid F16F9/465; self-pumping fluid springs in vehicle suspensions B60G17/044)} · CPC title

• F16F9/483

  characterised by giving a particular shape to the cylinder, e.g. conical · CPC title

• E05F5/025

  specially adapted for vehicle doors · CPC title

• F16F9/3207

  Constructional features (F16F9/34 - F16F9/50 take precedence; assembly or repair F16F9/3271) · CPC title