VIBRATING BODY FOR STATOR OF ULTRASONIC MOTOR AND MANUFACTURE THEREOF

摘要

PURPOSE:To reduce attenuation loss and improve bonding property between a piezo-electric element and a vibrating body by a method wherein the vibrating body is made of the principal material of an alloy, containing 80wt.% or more of tungsten or molybdenum and having 85% or more of logical density ratio while having 10.0X10-6 or less of thermal expansion coefficient, and is provided with multitude of grooves out with an uniform pitch on the surface of the same. CONSTITUTION:Tungsten powder and nickel powder, both of which are provided with the grain size of 5mum or less, and copper powder having the grain size of 15mum or less are mixed with a predetermined ratio to obtain the rectangular board of 100X10X1mm employing the binder of wax resin. On the other hand, an annular board, having an outer diameter of 60mm, width of 6 mm, thickness of 7 mm and having grooves of 4mm of depth, 1.2mm of width with the pitch of 10 deg. on one side, is molded by injection molding with the same composition as said rectangular board to use the annular bord as a stator. The molded form obtained in such a manner is heated in the nitrogen gas atmosphere of 300-400 deg.C to remove the binder and, thereafter, is sintered in hydrogen atmosphere to obtain a sintered body having the logical density ratio of 98%.