Abstract: A reduction gear configured to decelerate and output rotation of a motor includes two-stage planetary gear mechanisms that are provided side by side in an axial direction of the motor and are each configured of helical gears, and a case made of resin and formed into a cylindrical shape, the case incorporating the two-stage planetary gear mechanisms. At least one of an inner engagement ratio of a sun gear and a pinion gear of the planetary gear mechanism in a first stage and an outer engagement ratio of the pinion gear and a ring gear of the planetary gear mechanism in the first stage is 3.0 or more, and both the inner engagement ratio and the outer engagement ratio are larger than an engagement ratio of the planetary gear mechanism in a second stage.

Abstract: A reduction gear configured to decelerate and output rotation of a motor by two-stage planetary gear mechanisms disposed side by side in an axial direction includes: a case made of resin, the case being formed into a cylindrical shape in which the two-stage planetary gear mechanisms are incorporated, and having at least one of a lid portion and a bottom portion provided at each of both axial ends; and a reinforcing component that is formed of a material having a Young's modulus higher than a Young's modulus of a material of the case. The reinforcing component extends along at least a part of an inner peripheral surface in an axial central portion of the case.

Abstract: A reduction gear configured to decelerate and output rotation of a motor includes two-stage planetary gear mechanisms that are provided side by side in an axial direction of the motor and are each configured of helical gears, and a case made of resin and formed into a cylindrical shape, the case incorporating the two-stage planetary gear mechanisms. At least one of an inner engagement ratio of a sun gear and a pinion gear of the planetary gear mechanism in a first stage and an outer engagement ratio of the pinion gear and a ring gear of the planetary gear mechanism in the first stage is 3.0 or more, and both the inner engagement ratio and the outer engagement ratio are larger than an engagement ratio of the planetary gear mechanism in a second stage.

Abstract: A reduction gear configured to decelerate and output rotation of a motor by two-stage planetary gear mechanisms disposed side by side in an axial direction includes: a case made of resin, the case being formed into a cylindrical shape in which the two-stage planetary gear mechanisms are incorporated, and having at least one of a lid portion and a bottom portion provided at each of both axial ends; and a reinforcing component that is formed of a material having a Young's modulus higher than a Young's modulus of a material of the case. The reinforcing component extends along at least a part of an inner peripheral surface in an axial central portion of the case.

Abstract: A gearbox includes: a gearbox main body made of resin that constitutes a part of a speed reducer to which a motor is mounted; and a terminal that conducts power supplied from an external source to the motor. The gearbox main body includes a through hole formed to correspond to a mold that is used to maintain a position of the terminal while the terminal is being integrated with the gearbox main body by insert molding. The through hole may function as a vent hole in the gearbox main body.

Abstract: A gearbox includes: a gearbox main body made of resin that constitutes a part of a speed reducer to which a motor is mounted; and a terminal that conducts power supplied from an external source to the motor. The gearbox main body includes a through hole formed to correspond to a mold that is used to maintain a position of the terminal while the terminal is being integrated with the gearbox main body by insert molding. The through hole may function as a vent hole in the gearbox main body.