MAGNETORHEOLOGICAL FLUID DEVICES AND PROCESS OF CONTROLLING FORCE IN EXERCISE EQUIPMENT UTILIZING SAME

摘要

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.