Drive device

A drive device comprising:

• a reduction drive that reduces a speed of rotation produced by a motor, wherein the reduction drive includes at least two resin helical gears meshed with each other;
• an accommodation portion that accommodates the reduction drive, wherein the accommodation portion includes rotation supports that respectively support the at least two helical gears in a rotatable manner;
• and
• an output unit that outputs the rotation, of which the speed has been reduced by the reduction drive, to an outer side, wherein
• the accommodation portion includes a gear housing, which includes a gear accommodation portion capable of accommodating the at least two helical gears, and a housing cover, which closes an opening of the gear accommodation portion,
• the at least two helical gears include an output-side helical gear and another helical gear,
• the output-side helical gear is located closer to the output unit than the other helical gear in a power transmission path of the reduction drive,
• the rotation supports include a rotation support that supports the output-side helical gear and includes a first center axis and a rotation support that supports the other helical gear and includes a second center axis,
• the housing cover includes at least one restriction portion disposed so as to intersect a straight line intersecting the first center axis and the second center axis,
• the at least two helical gears are configured so that a thrust force, which directs from a bottom of the gear accommodation portion toward the housing cover, acts on a meshed portion of the at least two helical gears,
• the restriction portion projects from the housing cover toward the bottom of the gear accommodation portion,
• the output-side helical gear includes a first axial end surface facing toward the housing cover, and a second axial end surface facing toward the bottom of the gear accommodation portion, and
• the restriction portion is configured to allow for slidable contact with the first axial end surface of the output-side helical gear, which has received the rotation from the other helical gear, to restrict axial bending of the output-side helical gear caused by the thrust force acting on the meshed portion.