Development For Yoke Of Torque Sensor With High Performance, Low Cost, And High Quality

Majority of conventional the EPS(Electric Power Steering) adopted mechanical torque sensors having disadvantages such as noise from sliding and the low responsivity, which ought to be replaced by magnetic torque sensors.
The high responsivity is one of the greatest advantages of magnetic torque sensors, which is the most desirable characteristic to obtain through this development.  To satisfy this need, more magnetic flux must be gathered at the Hall elements, which brings a new challenge for manufacturing the yoke with a complicated shape.
It is uneconomical to form complicated shape with conventional electromagnetic steel sheet due to time-consuming processes involving machining, laminating of steel sheets with complicated shapes, and assembly with many processes.  Therefore, the new developed yoke was manufactured with following two technologies.
・Near net shape, which is an advantage of PM process.
・Quality Assurance technology
In this paper, we will explain in detail.