Methods and apparatus for controlling a fluid damper

• US 8,955,653 B2
• Filed: 10/12/2010
• Issued: 02/17/2015
• Est. Priority Date: 10/13/2009
• Status: Active Grant

• Current Assignee: Fox Factory Incorporated
• Original Assignee: Fox Factory Incorporated
• Inventors: Marking, John
• Primary Examiner(s): Siconolfi, Robert A
• Assistant Examiner(s): POON, CHARLES YULUNG
• Application Number:
  US12/902,239
• Publication Number:
  US 20110083929A1
• Time in Patent Office: 1,589 Days
• Field of Search: 188/267, 188/267.1, 188/267.2, 188/266.1, 188/269, 188/285, 188/298, 603/26, 91/4.A, 91/4.R
• US Class Current: 188/267.2
• CPC Class Codes: B60G 15/062 the spring being arranged around the damper B60G15/061, B60G15/067, B60G15/07 take precedence
• CPC Class Codes: B60G 15/12 and fluid damper
• CPC Class Codes: B60G 17/08 Characteristics of fluid dampers adjusting fluid dampers in general F16F9/44 - F16F9/53
• CPC Class Codes: B60G 2202/24 Fluid damper
• CPC Class Codes: B60G 2206/41 Dampers
• CPC Class Codes: B60G 2500/10 Damping action or damper
• CPC Class Codes: B60G 2600/22 Magnetic elements
• CPC Class Codes: B60G 2800/162 Reducing road induced vibrations
• CPC Class Codes: F16F 2222/06 Magnetic or electromagnetic
• CPC Class Codes: F16F 2224/045 magnetorheological
• CPC Class Codes: F16F 2228/066 Variable stiffness
• CPC Class Codes: F16F 9/061 Mono-tubular units
• CPC Class Codes: F16F 9/066 Units characterised by the partition, baffle or like element F16F9/068, F16F9/08 take precedence
• CPC Class Codes: F16F 9/53 Means for adjusting damping characteristics by varying fluid viscosity, e.g. electromagnetically F16F13/30 takes precedence; brakes comprising a medium with electrically or magnetically controlled friction F16D57/002; electrorheological fluids per se C10M171/001; magnetorheological fluids per se H01F1/447
• CPC Class Codes: F16F 9/535 Magnetorheological [MR] fluid dampers springs comprising magnetorheological [MR] elastomers F16F1/361

Abstract

A method and apparatus for a fluid damper comprising a first fluid-filled chamber, a second chamber filled with a fluid having variable flow characteristics and at least partially displaceable by the first fluid, and a gas chamber, the gas chamber compressible due to the displacement of the second chamber. In one embodiment, the fluid in the second chamber is a variable rheology fluid.

Claims

1. A fluid damper comprising:

a first chamber comprising a first end and a second end and defined by an annular wall coupling the first end with the second end, wherein the annular wall comprises an inner diameter, and wherein the first chamber is divided into a compression portion having a first fluid therein and a gas-filled compressible portion, the compression portion including a piston and a rod disposed therein and movable in a compression and rebound stroke within the first chamber;

a second chamber disposed within a portion less than a whole of the first chamber and between the first end and the second end, the second chamber comprising a portion of the annular wall having the inner diameter of the first chamber, the second chamber having a variable rheology fluid therein and dividing the compression portion and gas-filled compressible portion, wherein the second chamber is at least partially displaceable by and isolated from the first fluid and wherein movement of the second chamber causes a volume change in the gas-filled compressible portion; and

a magnet disposed within the second chamber, wherein the magnet is annularly-shaped and an outer surface of the magnet is positioned against an inner surface of the annular wall, the magnet comprising an orifice therein, wherein the variable rheology fluid has accessibility to an entirety of the orifice for movement therein, and wherein an increase of a current flowing in a wire of the magnet, and hence an increase in a magnetic field, enables flux lines created by the magnetic field to reach to a center of the orifice.

2. The damper of claim 1, wherein the magnet selectively produces a magnetic field within the second chamber to bring about a change in the rheology fluid.

3. The damper of claim 2, wherein a portion of the rheology fluid travels through the orifice when the second chamber is displaced.

4. The damper of claim 1, wherein the second chamber includes flexible end-walls permitting the second chamber to be displaced relative to the magnet and the magnet is an electromagnet.

5. The damper of claim 1, wherein a first wall of the second chamber is adjacent the compression portion and a second, opposite wall of the second chamber is adjacent the gas-filled compressible portion.

6. The damper of claim 1, wherein the rod includes a valve assembly positioned therein that permits and restricts fluid flow in a second fluid pathway.

7. A remotely controllable shock absorber system for a vehicle comprising:

at least two dampers associated with at least two wheels of the vehicle, each damper of the at least two dampers comprising;

a first chamber comprising a first end and a second end and defined by an annular wall coupling the first end with the second end, wherein the annular wall comprises an inner diameter, and wherein the cylinder is divided into a compression portion and a gas-filled compressible portion, the compression portion including piston and a rod for movement therein;

a second chamber disposed within a portion less than a whole of the first chamber and between the first end and the second end, the second chamber comprising a portion of the annular wall having the inner diameter of the first chamber, the second chamber being fluid-filled with a variable rheology fluid; and

a remotely actuatable electromagnet proximate the second chamber for affecting the fluid due to a magnetic field created by the electromagnet, wherein the surfaces of the second chamber through which the magnetic field of the electromagnet extends into the variable rheology fluid is coated with an abrasion resistant material, wherein the electromagnet is annularly-shaped and an outer surface of the electromagnet is positioned against an inner surface of the annular wall, the electromagnet comprising an orifice therein, wherein the variable rheology fluid has accessibility to an entirety of the orifice for movement therein, and wherein an increase of a current flowing in a wire of the magnet, and hence an increase in a magnetic field, enables flux lines created by the magnetic field to reach to a center of the orifice.

8. The system of claim 7, wherein the second chamber includes flexible end walls permitting the chamber to be displaced relative to the electromagnet.

9. The remotely controllable shock absorber system of claim 7, wherein each damper further includes a switch for selectively producing the magnetic field.

10. The remotely controllable shock absorber system of claim 9, wherein each damper further includes a logic/control unit with at least one input for operating the switch automatically.

11. The remotely controllable shock absorber system of claim 10, wherein the at least one input includes at least one of wheel speed, damper piston velocity, and piston rod position.

12. The remotely controllable shock absorber system of claim 11, wherein the switch is operable to incrementally increase or decrease the magnetic field depending upon the at least one input.