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US5549837A
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US
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Magnetic fluid-based magnetorheological fluids
Assignee: Ford Global Technologies LLC
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Filing: 1994-08-31
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Granted: 1996-08-27
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Expires: 2014-08-31
Abstract
Abstract A magnetorheological fluid composition having a magnetizable carrier medium loaded with magnetizable particles to provide a magnetorheological fluid exhibiting enhanced rheological properties. Also disclosed is a magnetic-particle damper utilizing the magnetorheological fluid composition.
Inventors
- 👤 John M. Ginder
- 👤 Larry D. Elie
- 👤 Lloyd C. Davis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:12
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/44; H01F1/447
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
38 words
A magnetorheological fluid composition, comprising: a magnetizable carrier fluid; and a multiplicity of magnetizable particles, each having substantially spheroidal shape, said magnetizable particles being suspended within said magnetizable carrier fluid to provide a fluid which exhibits magnetorheological properties.
Claim 2
Dependent Claim
38 words
A magnetorheological fluid composition, comprising: a magnetizable carrier fluid; and a multiplicity of magnetizable particles, each having substantially spheroidal shape, said magnetizable particles being suspended within said magnetizable carrier fluid to provide a fluid which exhibits magnetorheological properties.
Claim 3
Dependent Claim
14 words
The fluid composition of claim 1, wherein said magnetizable carrier fluid is a ferrofluid.
Claim 4
Dependent Claim
38 words
The fluid composition of claim 1, wherein said magnetizable carrier fluid and said multiplicity of magnetizable particles have similar densities so as to minimize sedimentation of said magnetizable particle from said carrier fluid within the magnetorheological fluid composition.
Claim 5
Dependent Claim
21 words
The fluid composition of claim 1, wherein said magnetizable carrier fluid is thixotropic to substantially reduce sedimentation of said magnetizable particles.
Claim 6
Dependent Claim
12 words
The fluid composition of claim 1, wherein said magnetizable particles are hollow.
Claim 7
Dependent Claim
18 words
The fluid composition of claim 1, wherein said magnetizable particles are coated with thin layers of magnetic material.
Claim 8
Dependent Claim
26 words
The fluid composition of claim 1, wherein said magnetizable particles are selected from the group consisting of iron, steel, cobalt, nickel, ferrite, garnet and alloys thereof.
Claim 9
Dependent Claim
24 words
The fluid composition of claim 1, wherein said magnetizable particles have an average particle size in the range of 100 nm to 0.1 mm.
Claim 10
Dependent Claim
23 words
The fluid composition of claim 1, wherein said magnetizable particles have a cylindrical shape to enhance shear stresses of the magnetorheological fluid composition.
Claim 11
Dependent Claim
19 words
The fluid composition of claim 1, wherein the fluid composition has a viscosity below 0.30 Pa-sec at 25° C.
Claim 12
Dependent Claim
28 words
The fluid composition of claim 1, wherein said magnetizable particles suspended with said magnetizable carrier fluid have a volume concentration in the range of approximately 5% to 60%.
Claim 13
Dependent Claim
39 words
A magnetorheoheological fluid composition, comprising: a ferrofluid carrier fluid; and a multiplicity of magnetizable particles, each having a substantially spheroidal shape, said magnetizable particles being suspended in said ferrofluid carrier fluid to provide a fluid which exhibits magnetorheological properties.
Claim 14
Dependent Claim
39 words
A magnetorheoheological fluid composition, comprising: a ferrofluid carrier fluid; and a multiplicity of magnetizable particles, each having a substantially spheroidal shape, said magnetizable particles being suspended in said ferrofluid carrier fluid to provide a fluid which exhibits magnetorheological properties.
Claim 15
Dependent Claim
16 words
The fluid composition of claim 12, wherein said ferrofluid has a density of about 1.24 g/cc.
Claim 16
Dependent Claim
18 words
The fluid composition of claim 12, wherein said ferrofluid has an average particle size of about 10 nm.
Claim 17
Dependent Claim
16 words
The fluid composition of claim 12, wherein said ferrofluid has an initial permeability of about 2.9.
Claim 18
Dependent Claim
17 words
The fluid composition of claim 12, wherein said magnetizable particles have a volume fraction of about 0.5.
Claim 19
Dependent Claim
14 words
The fluid composition of claim 12, wherein said magnetizable particles comprise carbonyl iron powder.
Claim 20
Dependent Claim
20 words
The fluid composition of claim 17, wherein said carbonyl iron powder has an average particle size of about 6 microns.
Claim 21
Dependent Claim
19 words
The fluid composition of claim 17, wherein said carbonyl iron powder has a mass density of about 8 g/cc.
Claim 22
Dependent Claim
77 words
A magnetic-particle damper, comprising: a housing; a piston located within said housing; a magnetorheological fluid composition located within said housing and positioned to be in mating contact with said piston, wherein said magnetorheological fluid composition comprises: a magnetizable carrier fluid; and a multiplicity of magnetizable particles suspended in said magnetizable carrier fluid; means for generating a magnetic field positioned near said magnetorheological fluid composition; and a shaft coupled to said piston, positioned to extend from said housing.
Claim 23
Dependent Claim
77 words
A magnetic-particle damper, comprising: a housing; a piston located within said housing; a magnetorheological fluid composition located within said housing and positioned to be in mating contact with said piston, wherein said magnetorheological fluid composition comprises: a magnetizable carrier fluid; and a multiplicity of magnetizable particles suspended in said magnetizable carrier fluid; means for generating a magnetic field positioned near said magnetorheological fluid composition; and a shaft coupled to said piston, positioned to extend from said housing.
References Cited (Backward Citations)
US2575360A
Cited
US2661825A
Cited
US4100088A
Cited
US5167850A
Cited
US4992190A
Cited
US5382373A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-08-27 | 2000-02-26 | 2000-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-08-27 | 2004-02-26 | 2004-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-08-27 | 2008-02-26 | 2008-08-27 | $7700.00 | Window Closed / Lapsed |