Abstract
A magnetorheological fluid clutch and an operation method are provided. The magnetorheological fluid clutch includes an output component, a permanent magnet, an input component, magnetorheological fluid, and a field blocker. The permanent magnet is disposed in an accommodating space of the output component. The input component is set into the output component. The magnetorheological fluid is disposed between the output component and the input component. The state of the magnetorheological fluid is controlled by a magnetic field generated from the permanent magnet. The field blocker is inserted into the space between the permanent magnet and the output component to control the intensity of the magnetic field.