Double element electroviscous fluid clutch

An electroviscous fluid clutch comprising:

• first and second members mounted for relative rotation about a common axis and defining cooperating shear surfaces forming an operating chamber therebetween;
• a return passageway operative to direct electroviscous fluid from said operating chamber to a storage chamber as a function of relative rotation between said members;
• a source of high voltage potential;
• and
• first and second electrodes in circuit with said source positioned to establish a variable electrostatic fluid within said return passageway to effect a change in the characteristic viscosity of fluid within said return passageway to effect modulation of electroviscous fluid flowing from said storage chamber to said operating chamber as a function of a sensed parametric input.

An electroviscous fluid clutch comprising:

• a first member secured for rotation with a shaft;
• a second member rotatably disposed on said shaft relative to said first member;
• shear surfaces disposed on said first and second members and forming an operating chamber therebetween;
• a fluid storage chamber disposed adjacent said operating chamber;
• pump means operative to displace electroviscous fluid from said operating chamber and discharge said fluid within said fluid storage chamber as a function of relative rotation between said first and second members;
• a return passageway effecting communication between said storage chamber and said operating chamber;
• a source of high voltage potential;
• and
• first and second electrodes carried with said first and second members, respectively, in circuit with said source and positioned to establish a variable electrostatic field within said return passageway to effect a change in the characteristic viscosity of fluid within said return passageway to modulate flow of fluid therethrough.

An electroviscous fluid clutch comprising:

• an electrically conductive clutch member secured for rotation with a shaft;
• an electrically conductive cover member rotatably disposed on said shaft relative to said first member and electrically insulated therefrom;
• shear surfaces disposed on said clutch and cover members and forming an operating chamber therebetween;
• means defining an annular fluid storage chamber carried by one of said members and disposed coaxially with said shaft;
• at least one pump defined by adjacent portions of said clutch member and cover member radially distal said shaft and operative to displace electroviscous fluid from said operating chamber radially inwardly to a point within said fluid storage chamber substantially adjacent the axis of said shaft and which is spaced above the uppermost surface level assumed by the electroviscous fluid within the storage chamber when substantially all of said fluid is disposed therein during periods of relatively low torque transmission through said clutch;
• a passageway operative to interconnect said fluid storage chamber and operating chamber;
• a first source of variable high voltage potential in circuit with said clutch and cover members whereby said clutch and cover members function as spaced electrodes when a voltage potential is applied there across to establish a variable electrostatic field within said operating chamber to effect a change in the characteristic viscosity of fluid within said operating chamber;
• a second source of high voltage potential;
• and
• a third electrode insulatingly carried by one of said members, in circuit with said second source of high voltage potential and positioned to selectively establish an electrostatic field within said return passageway to prevent electroviscous fluid in said fluid storage chamber from flowing into said operating chamber when said passageway electrostatic field is present and, in the absence of said passageway electrostatic field, to establish fluid communication between the radially outward most portion of said fluid storage chamber and said operating chamber, the electroviscous fluid flowing therebetween under the influence of centrifugal forces acting upon electroviscous fluid within said fluid storage chamber during periods of relatively high torque transmission through said clutch.