Power transmission device and drive device

A power transmission device comprising:

• a housing having a first chamber, a second chamber, and a center housing, the center housing being located between the first chamber and the second chamber;
• a first gear unit accommodated in the first chamber and having a first rotation shaft;
• and
• a second gear unit accommodated in the second chamber and having a second rotation shaft located coaxially with the first rotation shaft, wherein:
• the center housing has a flat plate portion, a first bearing support portion protruding from the flat plate portion toward the first chamber and supporting a first bearing located at a first end of the first rotation shaft, and a second bearing support portion protruding from the flat plate portion toward the second chamber and supporting a second bearing located at a first end of the second rotation shaft;
• and
• the flat plate portion is provided with a gap defined in at least a part of an annular region in the flat plate portion interposed between the first bearing support portion and the second bearing support portion, wherein the gap is a space defined inside the flat plate portion, the gap is provided over an entirety of the annular region, and the gap extends from the annular region to an outer peripheral edge of the flat plate portion along a first direction perpendicular to a rotation axis direction of the first rotation shaft.