초록 ▼

The invention relates to magnetorheological (MR) fluid devices and the process of controlling the force in exercise equipment by utilizing the MR fluid devices. The MR fluid devices include rotary and linear acting varieties and are useful for controlled forces in exercise bicycles, recumbent exerci

The invention relates to magnetorheological (MR) fluid devices and the process of controlling the force in exercise equipment by utilizing the MR fluid devices. The MR fluid devices include rotary and linear acting varieties and are useful for controlled forces in exercise bicycles, recumbent exercisers, ski machines, rowing machines, and stair stepper machines. The rotary MR fluid device is comprised of a rotor supported by bearings and received within a housing. An MR fluid is received adjacent the rotor and within a cavity in the housing and the MR fluid is controlled by an applied magnetic field to vary the operating torque resistance. Spring biasing the rotor allows for relaxed tolerances. Optimization of the Ri/Ro ratio is described which reduces the size and weight of the device. The linear acting version utilizes simple extensible pumps and an external MR fluid valve to provide a modularized system.

대표청구항 ▼

[ What is claimed is:] [1.] A magnetorheological fluid device, comprising:(a) a shaft for attaching to a first member;(b) a rotor having a first rotor surface and a second rotor surface which are outwardly facing and generally radially extending, said rotor having an outer radius Ro defining an oute

[ What is claimed is:] [1.] A magnetorheological fluid device, comprising:(a) a shaft for attaching to a first member;(b) a rotor having a first rotor surface and a second rotor surface which are outwardly facing and generally radially extending, said rotor having an outer radius Ro defining an outer periphery, said rotor connected to said shaft such that relative rotation is restrained;(c) a housing for attaching to a second member, said housing including a hollowed out cavity formed therein defined partially by a flux member which provides a magnetic flux path, said flux member including an inner radius Ri forming an innermost periphery and having a recess formed therein including a first inner surface and second inner surface which face each other, said recess receiving a portion of said rotor and forming a first gap between said first inner surface and said first rotor surface, and a second gap between said second inner surface and said second rotor surface, said inner radius Ri of said flux member and said outer radius Ro of said rotor sized in the ratio of Ri/Ro such that Ri/Ro ratio is between 0.70 and 0.99 such that a minimum amount of steel is required;(d) a magnetorheological fluid comprised of ferromagnetic particles disbursed in a viscous fluid contained within and at least partially filling said cavity and substantially filling said first and second gaps; and(e) a coil adjacent said first and second gaps for creating a standing magnetic field in said magnetic flux path which causes said magnetorheological fluid to change rheology and cause a change in a restraining force exerted upon said rotor.