Tdk Corporation

Shiro Tomizawa

Teruo Mori

Toshihiro Suzuki

Seigo Tokoro

Kesaharu Takatoh

Restoring magnetostriction characteristics without causing fusion of rod. By performing heat treatment on a giant magnetostrictive material within the temperature range of 750 to 860&#xb0; C., working distortion is removed while bleeding of an R-rich phase on a rod surface is prevented.

Giant magnetostrictive material and heat treatment method for giant magnetostrictive material

A torque sensor includes a substantially tubular giant magnetostrictive member, a shaft passing through the inner bore of the giant magnetostrictive member and capable of transmitting torque to the giant magnetostrictive member, and a detection coil for detecting changes in the magnetic permeability or remnant magnetization of the giant magnetostrictive member. Torque changes of the shaft are detected as changes in the magnetic permeability or remnant magnetization of the giant magnetostrictive member, based on the deformation of the giant magnetostrictive member. The torque sensor enables a reduction in the number of components and costs, as well as detection of torque changes with high sensitivity.

Torque sensing apparatus

In the step of sintering a compact that is finally to be a magnetostrictive element, when the temperature in a furnace is elevated, the atmosphere in the furnace is evacuated by a vacuum pump to keep the pressure in the furnace at negative pressure in a temperature range that allows thermal decomposition of hydride present in the compact to release hydrogen gas to accelerate release of hydrogen from the compact.

Growing community of inventors

Tokyo, Japan

Shiro Tomizawa