| 摘要 |
<p>A screw-fastener having a continuously-variable transmission traction drive is known in the related art. In such a screw-fastener, a driving source, the continuously-variable transmission, and a spindle are disposed to be coaxial with each other. In the invention, the continuously-variable transmission may be applied to power tools in which the spindle and an output shaft of the driving source are not coaxial with but are parallel to or intersect each other. In a disc grinder (30), a spindle (36) mounted with a grindstone (37) intersects an output shaft (34a) of an electric motor (34). The disc grinder (30) includes the three-point pressing continuously-variable transmission (1) between the output shaft (34a) of the electric motor (34) and a bevel gear train (35). The bevel gear train (35) is used for deceleration. The traction grease having a high traction coefficient is used as the lubricant of the traction drive. A grease reservoir (60) or felt members (63 and 64) arranged in sliding contact with the pressing parts are disposed in the transmission case (41). Accordingly, efficient lubrication using a small amount of traction grease can be accomplished.</p> |
