Patent attributes
A reduction gear unit capable of reducing vibrations caused by gear rattle, while permitting some degree of backlash in a pair of gears, is provided. A reduction gear unit is so configured that a pinion shaft and a main gear shaft are disposed in parallel to each other, and a pinion 1 mounted on the pinion shaft and a main gear 2 mounted on the main gear shaft are arranged to mesh with each other, so as to transmit a rotation of the pinion shaft to the main gear shaft, and includes a housing 11 that encloses the pinion 1 and the main gear 2, where the housing 11 has an inner surface whose width, in a cross section perpendicular to an axial direction of the pinion shaft and the main gear shaft, perpendicular to an imaginary line that connects centers of the pinion shaft and the main gear shaft evenly increases from a pinion side toward a main gear side between ends of arcuate regions respectively enclosing the main gear and the pinion. The housing 11 contains a resin lubricant of a sufficient amount for immersing a part of a portion where the pinion 1 and the main gear 2 mesh with each other.
