Self-sustaining shimmy damper system for landing gear shock strut assemblies

Patent metadata

Field	Value
Publication number	US-12384530-B2
Application number	US-202217673941-A
Country	US
Kind code	B2
Filing date	Feb 17, 2022
Priority date	Dec 14, 2021
Publication date	Aug 12, 2025
Grant date	Aug 12, 2025

Abstract

A shimmy damper assembly may comprise: a damper piston including a piston head, the piston head comprising a first permanent magnet, a shimmy cylinder including a second permanent magnet disposed on an axial surface of the shimmy cylinder, and a gland nut coupled to the shimmy cylinder, the gland nut including a third permanent magnet spaced apart axially from the second permanent magnet, the piston head disposed between the first permanent magnet and the second permanent magnet.

First claim

What is claimed is:

1. A shimmy damper assembly, comprising:
a damper piston including a piston head, the piston head comprising a first permanent magnet, the piston head comprising an orifice disposed axially therethrough;
a shimmy cylinder assembly comprising a shimmy cylinder and a gland nut, the shimmy cylinder including a second permanent magnet disposed on an axial surface of the shimmy cylinder, the gland nut coupled to the shimmy cylinder, the gland nut including a third permanent magnet spaced apart axially from the second permanent magnet, the piston head disposed between the first permanent magnet and the second permanent magnet; and
a magnetorheological (MR) fluid disposed in a cavity of the shimmy cylinder assembly, the shimmy cylinder assembly including the shimmy cylinder and the gland nut, wherein:
the cavity is defined radially between a radially outer surface of the damper piston and a radially inner surface of the shimmy cylinder and the gland nut,
the cavity is defined axially between the second permanent magnet and the third permanent magnet,
the MR fluid is only disposed in the cavity,
the damper piston extends entirely through the shimmy cylinder assembly,
an annular orifice is defined between the radially outer surface of the piston head and the radially inner surface of the gland nut and the shimmy cylinder,
the first permanent magnet, the second permanent magnet, and the third permanent magnet each comprise a first pole and a second pole, and wherein the first permanent magnet comprises the second pole spaced apart axially proximate the second pole of the second permanent magnet, and
the first pole of the first permanent magnet is disposed on a first axial surface of the piston head and the second pole of the first permanent magnet is disposed on a second axial surface of the piston head, the first axial surface disposed axially opposite the second axial surface.

2. The shimmy damper assembly of claim 1 , wherein the first permanent magnet, the second permanent magnet, and the third permanent magnet are oriented in a manner to form a Halbach array.

3. The shimmy damper assembly of claim 1 , wherein:
the first pole is one of a north seeking (“N”) pole and a south seeking (“S”) pole, and
the second pole is the other of the north seeking (“N”) pole and the south seeking (“S”) pole.

4. A landing gear, comprising:
an axle configured to support a tire;
a shock strut assembly coupled to the axle, the shock strut assembly including:
a strut cylinder;
a strut piston configured to telescope relative to the strut cylinder;
a shimmy damper assembly configured to reduce horizontal rotation of the axle during operation of the landing gear, the shimmy damper assembly comprising:
a damper piston having a piston rod and a piston head, the piston head including a first permanent magnet disposed thereon, wherein the piston head comprises an orifice disposed axially therethrough,
a shimmy cylinder assembly comprising a shimmy cylinder and a gland nut, the shimmy cylinder assembly at least partially defining a cavity, the shimmy cylinder assembly having a second permanent magnet and a third permanent magnet disposed within the cavity, wherein the first permanent magnet, the second permanent magnet and the third permanent magnet are oriented in a manner to form a Halbach array within the cavity,
a magnetorheological (MR) fluid disposed in the cavity of the shimmy cylinder assembly, wherein:
the cavity is defined radially between a radially outer surface of the damper piston and a radially inner surface of the shimmy cylinder and the gland nut,
the cavity is defined axially between the second permanent magnet and the third permanent magnet,
the MR fluid is only disposed in the cavity,
an annular orifice is defined between the radially outer surface of the piston head and the radially inner surface of the gland nut and the shimmy cylinder,
the first permanent magnet, the second permanent magnet, and the third permanent magnet each comprise a first pole and a second pole, and wherein the first permanent magnet comprises the second pole spaced apart axially proximate the second pole of the second permanent magnet, and
the first pole of the first permanent magnet is disposed on a first axial surface of the piston head and the second pole of the first permanent magnet is disposed on a second axial surface of the piston head, the first axial surface disposed axially opposite the second axial surface; and

a torque link including an upper arm and a lower arm, the upper arm coupled to the strut cylinder, the lower arm coupled to at least one of the strut piston and the axle, the upper arm pivotably coupled to the lower arm via the damper piston of the shimmy damper assembly.

5. The landing gear of claim 4 , wherein the piston head is configured to self-center within the cavity in response to traveling axially towards one of the second permanent magnet and the third permanent magnet.

6. The landing gear of claim 4 , wherein the shimmy damper assembly is configured to passively dampen the damper piston.

7. A method of manufacturing a shimmy damper system, the method comprising:
installing a first permanent magnet on a piston head of a piston;
installing a second permanent magnet on an axial surface of a shimmy cylinder of a shimmy cylinder assembly;
installing a third permanent magnet on an axial surface of a gland nut of the shimmy cylinder assembly;
coupling the gland nut to the shimmy cylinder to form the shimmy cylinder assembly and to operably couple the shimmy cylinder assembly the piston, the shimmy cylinder assembly at least partially defining a cavity therein, the cavity defined axially between the axial surface of the shimmy cylinder and the axial surface of the gland nut, the piston head disposed within the cavity, the piston head comprising an orifice disposed axially therethrough, the piston extending entirely through the shimmy cylinder assembly, wherein:
the cavity is defined radially between a radially outer surface of the piston and a radially inner surface of the shimmy cylinder and the gland nut,
the cavity is defined axially between the second permanent magnet and the third permanent magnet,
an annular orifice is defined between the radially outer surface of the piston head and the radially inner surface of the gland nut and the shimmy cylinder,
the first permanent magnet, the second permanent magnet, and the third permanent magnet each comprise a first pole and a second pole, and wherein the first permanent magnet comprises the second pole spaced apart axially proximate the second pole of the second permanent magnet, and
the first pole of the first permanent magnet is disposed on a first axial surface of the piston head and the second pole of the first permanent magnet is disposed on a second axial surface of the piston head, the first axial surface disposed axially opposite the second axial surface;

filling only the cavity with a magnetorheological (MR) fluid; and
sealing the cavity from an external environment.

Assignees

• Goodrich Corp

Inventors

• Nagaraja Hemanth
• Bodki Basavaraj
• Jain Bhuwan

Classifications

• F16F9/535

  Magnetorheological [MR] fluid dampers (springs comprising magnetorheological [MR] elastomers F16F1/361) · CPC title

• F16F9/3271

  Assembly or repair · CPC title

• F16F2226/04

  Assembly or fixing methods; methods to form or fashion parts · CPC title

• B64C25/60 Primary

  Oleo legs · CPC title

• F16F6/005

  using permanent magnets only · CPC title