| 摘要 |
<p>There is provided a dental handpiece capable of withstanding a higher torque load. The handpiece comprises a first rotating shaft 3 which is supported rotatably in a rear casing 2R and to which the rotation of a driving source is transmitted, and a second rotating shaft 9 which is supported rotatably in a front casing 2F and to which the rotation of the first rotating shaft 3 is transmitted. A bearing 12 and a bearing 14 are disposed at a predetermined interval in a jacket 8 fixed in the front casing 2F to rotatably support the second rotating shaft 9, and additionally, a bearing 13 is disposed between the bearing 12 and the bearing 14. The third bearing 13 reduces the whirling of the second rotating shaft 9, thereby preventing the wearing and chipping of the teeth of gears caused by a shift of meshing positions between a first gear 5 and a second gear 10 and a shift of meshing positions between a third gear 11 and a fourth gear 73.</p> |
