Gear device

1. A gear device, comprising:

a housing that accommodates gears;

a cover that covers an opening of the housing; and

a positioning portion that positions the cover relative to the housing; wherein

the cover includes a first bearing that receives a first shaft of one of the gears and a second bearing that receives a second shaft of another one of the gears,

the positioning portion guides the cover to a predetermined position on the housing and includes a projection that projects from one of the housing or the cover parallel to the first shaft or the second shaft and a fitting hole that is formed in the other one of the housing or the cover to receive the projection, and

the projection has a length that is set so that when coupling the cover to the housing, in a state in which the first shaft is inserted through the first bearing, the projection enters the fitting hole, and then a distal end of the second shaft enters the second bearing.

2. The gear device according to claim 1 , wherein the projection has a distal end that includes a tapered portion.

3. The gear device according to claim 2 , wherein the second shaft has a length that is set so that when the tapered portion of the projection is located in the fitting hole, the distal end of the second shaft is fitted in the second bearing.

4. The gear device according to claim 1 , wherein

the projection and a wall of the fitting hole form a gap therebetween including a first gap portion in a rotation direction of the first shaft and a second gap portion in a radial direction of the first shaft, and

the first gap portion is smaller than the second gap portion.