US5252249A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Powder and electrorheological fluid
Assignee: Bridgestone Corp
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Filing: 1991-04-10
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Granted: 1993-10-12
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Expires: 2011-04-10
Abstract
Abstract A powder having improved oxidation resistance and controlled electrical properties is obtained by dispersing minute particulates in a matrix phase to form composite particles. The minute particulates may be distributed uniformly or non-uniformly such that the particulates are dense near the surface and sparse near the center of each particle or inversely. The matrix phase has a moderate conductivity of 10 -10 to 10 2 Scm -1 , and the dispersed particulates have a low conductivity of up to 1/10 of that of the matrix phase, typically up to 10 -2 Scm -1 . Alternatively, the matrix phase has a lower conductivity and the dispersed particulates have a moderate conductivity. The powder is dispersed in an insulating oily medium to form an electrorheological fluid.
Inventors
- 👤 Yasuo Kurachi
- 👤 Tasuku Saito
- 👤 Yoshiki Fukuyama
- 👤 Shigeki Endo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:52
CPC Classifications
H; H01; H01B; H01B1/00; H01B1/04; C; C10; C10M; C10M171/00; C10M171/001; H01B1/14; H01B1/18; H01B1/20; H01B1/24
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
100 words
An electrorheological fluid, comprising a powder dispersed in an electrically insulating oily medium, said powder comprising composite particles comprised of a matrix phase having minute particulates uniformly dispersed therein, wherein said matrix phase has an electrical conductivity of 10 -10 to 10 2 Scm -1 , said dispersed particulates have an electrical conductivity of up to 10 -2 Scm -1 and in the range of 1/10 to 1/10 14 of the electrical conductivity of said matrix phase, and said dispersed particulates are present in an amount of 0.1 to 70% by weight based on the weight of each composite particle.
Claim 2
Dependent Claim
100 words
An electrorheological fluid, comprising a powder dispersed in an electrically insulating oily medium, said powder comprising composite particles comprised of a matrix phase having minute particulates uniformly dispersed therein, wherein said matrix phase has an electrical conductivity of 10 -10 to 10 2 Scm -1 , said dispersed particulates have an electrical conductivity of up to 10 -2 Scm -1 and in the range of 1/10 to 1/10 14 of the electrical conductivity of said matrix phase, and said dispersed particulates are present in an amount of 0.1 to 70% by weight based on the weight of each composite particle.
Claim 3
Dependent Claim
138 words
An electrorheological fluid, comprising a powder dispersed in an electrically insulating oily medium, said powder comprising composite particles comprised of a matrix phase having minute particulates non-uniformly dispersed therein such that either (1) more minute particulates are present near the surface than near the center of the composite particle or (2) more minute particulates are present near the center than near the surface of the composite particle; wherein said matrix phase has an electrical conductivity of 10 -10 to 10 2 Scm -1 , said dispersed particulates have an electrical conductivity of up to 10 -2 Scm -1 and in the range of 1/10 to 1/10 14 of the electrical conductivity of said matrix phase, and said dispersed particulates are present in an amount of 0.01 to 40% by weight based on the weight of each composite particle.
Claim 4
Dependent Claim
138 words
An electrorheological fluid, comprising a powder dispersed in an electrically insulating oily medium, said powder comprising composite particles comprised of a matrix phase having minute particulates non-uniformly dispersed therein such that either (1) more minute particulates are present near the surface than near the center of the composite particle or (2) more minute particulates are present near the center than near the surface of the composite particle; wherein said matrix phase has an electrical conductivity of 10 -10 to 10 2 Scm -1 , said dispersed particulates have an electrical conductivity of up to 10 -2 Scm -1 and in the range of 1/10 to 1/10 14 of the electrical conductivity of said matrix phase, and said dispersed particulates are present in an amount of 0.01 to 40% by weight based on the weight of each composite particle.
Claim 5
Dependent Claim
99 words
An electrorheological fluid, comprising a powder dispersed in an electrically insulating oily medium, said powder comprising composite particles comprised of a matrix phase having minute particulates dispersed therein, wherein said matrix phase has an electrical conductivity of up to 10 -2 Scm -1 , said dispersed particulates have an electrical conductivity of 10 -10 to 10 2 Scm -1 and in the range of 10 to 10 14 times the electrical conductivity of said matrix phase, and said dispersed particulates are present in an amount of 15 to 99.5% by weight based on the weight of each composite particle.
Claim 6
Dependent Claim
99 words
An electrorheological fluid, comprising a powder dispersed in an electrically insulating oily medium, said powder comprising composite particles comprised of a matrix phase having minute particulates dispersed therein, wherein said matrix phase has an electrical conductivity of up to 10 -2 Scm -1 , said dispersed particulates have an electrical conductivity of 10 -10 to 10 2 Scm -1 and in the range of 10 to 10 14 times the electrical conductivity of said matrix phase, and said dispersed particulates are present in an amount of 15 to 99.5% by weight based on the weight of each composite particle.
Claim 7
Dependent Claim
43 words
The electrorheological fluid according to claim 1, 2, or 10, wherein said composite particles have a mean particle size of 0.1 to 100 μm and the size of said minute particulates is in the range from about 1 nm to about 1 μm.
Claim 8
Dependent Claim
32 words
The electrorheological fluid according to claim 1, 2, or 10, wherein said fluid comprises 1 to 60% by weight of said powder and 99 to 40% by weight of said oily medium.
Claim 9
Dependent Claim
39 words
The electrorheological fluid according to claim 1 or 2, wherein said matrix phase is comprised of a material selected from the group consisting of carbonaceous materials, boron carbide, aluminum carbide, polyaniline, poly(acene-quinone), zinc oxide, potassium titanate, and barium titanate.
Claim 10
Dependent Claim
45 words
The electrorheological fluid according to claim 8 or 9, wherein said minute particulate is comprised of a material selected from the group consisting of aluminum oxide, silica, boron oxide, titania, calcium oxide, iron oxide, tin oxide, zinc oxide, silicon carbide, silicon nitride, and aluminum nitride.
Claim 11
Dependent Claim
34 words
The electrorheological fluid according to claim 3, wherein said matrix phase is comprised of a material selected from the group consisting of metal alkoxides, organometallic complexes, and esters of organic compounds with inorganic acids.
Claim 12
Dependent Claim
29 words
The electrorheological fluid according to claim 3, wherein said minute particulate is comprised of a material selected from the group consisting of phenol resins, furan resins, and polydimethylsilane resins.
Claim 13
Dependent Claim
34 words
The electrorheological fluid according to claim 1, 2, or 3, wherein said oily medium is selected from the group consisting of hydrocarbon fluids, ester fluids, aromatic fluids, silicone fluids, fluorosilicone fluids, and mixtures thereof.
Claim 14
Dependent Claim
18 words
The electrorheological fluid according to claim 10, wherein said oily medium is polydimethylsiloxane, polymethylphenylsiloxane or a mixture thereof.
Claim 15
Dependent Claim
34 words
The electrorheological fluid according to claim 1, wherein said minute particulate is comprised of a material selected from the group consisting of metal alkoxides, organometallic complexes, and esters of organic compounds with inorganic acids.
Claim 16
Dependent Claim
29 words
The electrorheological fluid according to claim 1, wherein said matrix phase is comprised of a material selected from the group consisting of phenol resins, furan resins, and polydimethylsilane resins.
Claim 17
Dependent Claim
43 words
The electrorheological fluid according to claim 3, wherein said matrix phase is comprised of a material selected from the group consisting of aluminum oxide, silica, boron oxide, titania, calcium oxide, iron oxide, tin oxide, zinc oxide, silicon carbide, silicon nitride, and aluminum nitride.
Claim 18
Dependent Claim
36 words
The electrorheological fluid according to claim 3, wherein minute particulate is comprised of a material selected from the group consisting of carbonaceous materials, boron carbide, aluminum carbide, polyaniline, poly(acene-quinone), zinc oxide, potassium titanate, and barium titanate.
References Cited (Backward Citations)
US3923697A
Cited
US4110260A
Cited
JPS5393186A
Cited
US4282117A
Cited
US4224068A
Cited
US4786438A
Cited
GB2170510A
Cited
JPS61216202A
Cited
JPS6295397A
Cited
US4795735A
Cited
JPS6397694A
Cited
US4958998A
Cited
US4958998B1
Cited
US4816184A
Cited
JPH01164823A
Cited
JPH01180240A
Cited
US4865772A
Cited
JPH02169695A
Cited
JPH0631211A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-10-11 | 1997-04-12 | 1997-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-10-11 | 2001-04-12 | 2001-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-10-11 | 2005-04-12 | 2005-10-12 | $7700.00 | Window Closed / Lapsed |