| 摘要 |
Rare earth metal switched magnetic devices that comprise one or more magnets, a rare earth metal element positioned in the magnetic field produced by the magnet(s) and a system for controlling the temperature of the rare earth metal element are disclosed. The rare earth metal element is formed of a rare earth metal or rare earth metal alloy having magnetic properties that change from ferromagnetic to paramagnetic when heated above the Curie temperature of the chosen rare earth metal or rare earth metal alloy. Preferably the Curie temperature of the chosen rare earth metal or rare earth metal alloy is at or below the ambient temperature in which the rare earth metal switched magnetic device is to be used-approximately room temperature (70° F.) in the case of devices intended for use in a factory. Tailored Curie temperatures can be obtained by alloying rare earth metals together and/or with conventional switchable "soft" magnetic metals-iron, nickel, and cobalt. Three suitable rare earth metals are gadolinium, terbium, and dysprosium. Switching is produced by controlling the temperature of the rare earth metal element. When the temperature of the rare earth metal element is reduced below the Curie temperature of the rare earth metal or rare earth metal alloy, the ferromagnetic properties of the rare earth metal element cause the element to interact with the magnetic field produced by the magnet(s). When the temperature of the rare earth metal element is raised above the Curie temperature of the rare earth metal or rare earth metal alloy, the loss of ferromagnetism substantially reduces, if not entirely eliminates, the interaction between the rare earth metal element and the magnetic field produced by the magnet(s). Disclosed are clamps, lifters, riveters, valves, and actuators. |
