Magneto-rheological fluid device

• US 6,471,018 B1
• Filed: 11/19/1999
• Issued: 10/29/2002
• Est. Priority Date: 11/20/1998
• Status: Expired due to Fees

• Current Assignee: Board of Regents Nevada System of Higher Education (State of Nevada)
• Original Assignee: Board of Regents Nevada System of Higher Education (State of Nevada)
• Inventors: Kelso, Shawn P., Gordaninejad, Faramarz
• Primary Examiner(s): Rodriguez, Pam
• Application Number:
  US09/443,351
• Time in Patent Office: 1,075 Days
• Field of Search: 188/267.1, 188/267, 188/267.2, 188/269, 188/322.15, 188/322.22, 188/322.19, 267/140.14
• US Class Current: 188/267.1
• CPC Class Codes: F16F 9/535 Magnetorheological [MR] fluid dampers springs comprising magnetorheological [MR] elastomers F16F1/361

Abstract

A magneto-rheological fluid device including a housing defining a cavity, a piston slidably disposed in the cavity to divide the cavity into first and second portions, a passage defined on an exterior surface of the piston fluidly coupling the first and second portions of the cavity, a magneto-rheological fluid disposed in the cavity such that motion of the piston is damped by flow of the magneto-rheological fluid through the passage and a magnet disposed to produce a magnetic field within the cavity substantially parallel to the motion of the piston at the exterior surface of the piston.

Claims

1. A magneto-rheological fluid device, comprising:

a housing defining a cavity;

a piston slidably disposed in the cavity, the piston dividing the cavity into first and second portions;

a passage defined on an exterior surface of the piston fluidly coupling the first and second portions of the cavity;

a magneto-rheological fluid disposed in the cavity such that motion of the piston is damped by flow of the magneto-rheological fluid through the passage; and

a magnet disposed to produce a magnetic field within the cavity substantially parallel to the motion of the piston at the exterior surface of the piston.

2. The magneto-rheological fluid device according to claim 1, wherein the piston is formed of a non-magnetic material.

3. The magneto-rheological fluid device according to claim 2, wherein the housing is formed of a non-magnetic material.

4. The magneto-rheological fluid device according to claim 2, wherein amount of damping varies according to a magnitude of the magnetic field.

5. The magneto-rheological fluid device according to claim 1, wherein the housing is formed of a ferrous material.

6. The magneto-rheological fluid device according to claim 1, further comprising a second piston slidably disposed in the cavity, the second piston further dividing the cavity into a third portion.

7. The magneto-rheological fluid device according to claim 1, wherein amount of damping varies according to a magnitude of the magnetic field.

8. The magneto-rheological fluid device according to claim 1, wherein the magnet includes an electromagnet.

9. The magneto-rheological fluid device according to claim 1, wherein the magnet is disposed around the housing.

10. The magneto-rheological fluid device according to claim 1, wherein the magnet is disposed around the piston in a piston body.

11. The magneto-rheological fluid device according to claim 1, wherein a sleeve is disposed around the piston in a piston body.

12. The magneto-rheological fluid device according to claim 1, wherein the passage includes an axial portion and a transverse portion formed on the exterior surface of the piston.

13. The magneto-rheological fluid device according to claim 12, wherein the transverse portion is formed along a circumference of the piston.

14. The magneto-rheological fluid device according to claim 1, wherein the magneto-rheological fluid forms chains parallel to the passage in response to the magnetic field.

15. The magneto-rheological fluid device according to claim 1, further comprising an end cap.

16. The magneto-rheological fluid device according to claim 15, wherein the end cap includes a ferrous material to direct the magnetic field.

17. The magneto-rheological fluid device according to claim 1, further comprising a cover disposed around the magnet.

18. The magneto-rheological fluid device according to claim 17, wherein the cover is formed of a ferrous material to provide a return path for the magnetic field.