PROBLEM TO BE SOLVED: To perform transmission such that a tooth cutting bar can be moved back and forth in the axial direction of the tooth cutting bar as well, and to inhibit use of a gear for the transmission of rotation further, when transmitting the rotation of a rotary shaft rotated by a motor or the like to the tooth cutting bar, in a micromotor for dental treatment.SOLUTION: The micromotor handpiece for dental treatment includes a rotary shaft 2 disposed inside a handpiece 1 and a rotary cylinder 3 disposed inside a head part 1 and rotated by the rotary shaft 2, the tooth cutting bar is inserted to the rotary cylinder 3 and a tooth is treated. The rotary shaft 2 has a projection part 2a eccentric to the rotary shaft 2, the rotary cylinder 3 has a peripheral groove 3a to which the projection part 2a is to be inserted, and when the rotary shaft 2 is rotated, the rotary cylinder 3 is moved back and forth in the axial direction. The rotary shaft 2 has a large diameter part 2b whose front surface is the base part of the projection part 2a, the rotary cylinder 3 has a large diameter part 3b to be in contact with the front surface of the large diameter part, the outer peripheral surface of the large diameter part 3b is in frictional contact with the radius part 2b of the large diameter part surface of the rotary shaft 2, and the rotation of the rotary shaft 2 is transmitted to the rotary cylinder 3.COPYRIGHT: (C)2013,JPO&INPIT【課題】歯科治療用マイクロモータにおいて、モータ等によって回転される回転軸の回転を歯牙切削バーに伝達するに当り、歯牙切削バーを該歯牙切削バーの軸方向にも往復動可能に伝達するようにし、更には、回転の伝達に歯車を使用しないようにした。【解決手段】ハンドピース1内に配設された回転軸2と、ヘッド部1内に配設され回転軸2によって回転される回転筒3とを有し、回転筒3に歯牙切削バーを挿着して歯牙の治療を行う。回転軸2は先端部に回転軸2に対して偏心した突出部2aを有し、回転筒3は突出部2aが挿入される周溝3aを有し、回転軸2が回転された時に、回転筒3が軸方向に往復動する。回転軸2は突起部2aの基部を前表面とする大径部2bを有し、回転筒3は大径部前表面と接触する大径部3bを有し、該大径部3bの外周面は回転軸2の大径部表面の半径部分2b’と摩擦接触し、回転軸2の回転を回転筒3に伝達する。【選択図】図1
