PROBLEM TO BE SOLVED: To provide an air turbine handpiece that can reliably perform air cooling of a bearing in a handpiece head using drive air for driving an air turbine.SOLUTION: The air turbine handpiece is provided in which, inside a handpiece head 3, a shaft body 25 with a chuck being a rotary shaft freely rotatably supported by two bearings 26, 27 is provided, also an impeller 24 integrated with the shaft body with the chuck is provided at a position between the two bearings, and the impeller is rotationally driven by the drive air into the handpiece head 3. The air turbine handpiece is configured in such a manner that: air pool flow path parts 41, 42 for supply air are provided in an outer circumferential part of each outer ring 37 constituting each bearing or around the outer circumferential part of each outer ring a plurality of air passage holes 40 for bringing the air pool flow path parts into communication with the inside of the bearing are provided in the area not applicable to a rolling contact surface of a rolling element of an inner circumference in each outer ring constituting each bearing and thereby enabling the drive air to be supplied in the area where the rolling element 38 is positioned between the outer ring and an inner ring 36 of two bearings via each air pool flow path part and each air passage hole by branching the drive air, respectively.SELECTED DRAWING: Figure 2COPYRIGHT: (C)2017,JPO&INPIT【課題】エアタービン駆動用の駆動エアを利用し、ハンドピースヘッド内の軸受の空冷を確実に実行できるエアタービンハンドピースを提供する。【解決手段】ハンドピースヘッド3の内部に二つの軸受26、27にて回転自在に支持された回転軸であるチャック付き軸体25と、二つの軸受の間の位置でチャック付き軸体と一体化された羽車24とを設け、ハンドピースヘッド3内への駆動エアにて羽車を回転駆動し、各軸受を構成する各外輪37の外周部又は各外輪の外周部の周りに供給エア用のエア溜まり流路部41、42を設け、各軸受を構成する各外輪におけるその内周の転動体の転動面に該当しない領域に、エア溜まり流路部を前記軸受の内部に連通させる1つ又は複数のエア通過孔40を設け、駆動エアを分岐して各エア溜まり流路部各エア通過孔を経て二つの軸受の外輪と内輪36との間の転動体38が位置する領域に各々駆動エアを供給可能とした構成とする。【選択図】図2
