| 摘要 |
<p>Provided are a reduction gear having a holder that is easily installed in a housing and suppresses teeth beating noise produced at a gear meshing portion, and an electric power steering device having the reduction gear. The holder (19) and a biasing member (20) are disposed at the bottom of a blind-ended bore of the housing (11). A coil spring (21) is coiled between the outer peripheries of the biasing member (20) and the holder (19). The holder (19) and the outer ring of a ball bearing (15) are fitted to a step part (11a) of the housing (11). A wave washer (17) and a retainer (16) are disposed outside the ball bearing (15) and axially press the ball bearing to fix it at position. An end (12c) of a worm shaft is inserted into the hole (20a) of the biasing member, and a small-diameter part (12b) of the worm shaft is inserted and supported in a bush (18) in the inner ring of the ball bearing (15). The worm shaft is elastically displaceable by elastic deformation of the coiled spring (21) and a bush (18) and an effect of the wave washer (17), and the displacement of the work shaft applies a preload to the worm meshing part. Consequently, the occurrence of the teeth beating noise of the meshing portion can be suppressed.</p> |
