Patents Assigned to Toyohisa Fujita
  • Electrorheological magnetic fluid and process for producing the same
    Patent number: 6159396
    Abstract: An electrorheological magnetic fluid including an electrically insulating liquid and fine particles dispersed therein is described, wherein the fine particles include a fine magnetic particle as a core, wherein the fine magnetic particle has a surface which is covered by an electroconductive substance, and the fine magnetic particle with its surface covered by the electroconductive substance is completely coated with a surfactant. A process for producing the electrorheological magnetic fluid is also described.
    Type: Grant
    Filed: May 19, 1997
    Date of Patent: December 12, 2000
    Assignees: Toyohisa Fujita, Nittetsu Mining Co., Ltd., Hitachi Powdered Metal Co., Ltd.
    Inventors: Toyohisa Fujita, Kenji Yoshino
  • Electrorheological magnetic fluid and process for producing the same
    Patent number: 5714084
    Abstract: An electrorheological magnetic fluid including an electrically insulating liquid and fine particles dispersed therein is described, wherein the fine particles include a fine magnetic particle as a core, wherein the fine magnetic particle has a surface which is covered by an electroconductive substance, and the fine magnetic particle with its surface covered by the electroconductive substance is completely coated with a surfactant. A process for producing the electrorheological magnetic fluid is also described.
    Type: Grant
    Filed: December 27, 1995
    Date of Patent: February 3, 1998
    Assignees: Toyohisa Fujita, Nittetsu Mining Co., Ltd., Hitachi Powdered Metals Co., Ltd.
    Inventors: Toyohisa Fujita, Kenji Yoshino
  • Electrorheological magnetic fluid and process for producing the same
    Patent number: 5507967
    Abstract: An electrorheological magnetic fluid including an electrically insulating liquid and fine particles dispersed therein is described, wherein the fine particles include a fine magnetic particle as a core, wherein the fine magnetic particle has a surface which is covered by an electroconductive substance, and the fine magnetic particle with its surface covered by the electroconductive substance is completely coated with a surfactant. A process for producing the electrorheological magnetic fluid is also described.
    Type: Grant
    Filed: November 16, 1994
    Date of Patent: April 16, 1996
    Assignees: Toyohisa Fujita, Nittetsu Mining Co., Ltd., Hitachi Powdered Metals Co., Ltd.
    Inventors: Toyohisa Fujita, Kenji Yoshino