Abstract: A gear module includes a rotating cylinder, a first planetary gear set, a second planetary gear set, a concave-convex structure, and a limit bearing set. The first planetary gear set is accommodated in the rotating cylinder and includes a driven gear; the second planetary gear set includes a positioning frame, second planetary gears pivoted to a positioning frame, a driven gear engaged with the second planetary gears, and the positioning frame has a through hole; the concave-convex structure includes a convex column extended from the rotating cylinder and a concave hole formed on the positioning frame, the convex column is plugged into the concave hole; the limit bearing set includes a first ball bearing sheathing the driven gear and mounted between the driven gear and the through hole, and a second ball bearing sheathing the convex column and mounted between the convex column and the concave hole.

Abstract: A low rotational speed gear module includes a fixed tube member, a rotational sleeve, a first planetary gear set, a sun gear, and a second planetary gear set. The fixed tube member includes a first inner gear. The rotational sleeve includes a second inner gear. The first planetary gear set includes a fixing plate, first planetary gears fixed to one side of the fixing plate, and a driven gear fixed to the other side of the fixing plate. The first planetary gear is engaged at one side with the sun gear and engaged at another side with the first inner gear. The second planetary gear set includes second planetary gears. The second planetary gears is engaged at one side with the driven gear and engaged at another side with the first inner gear and the second inner gear.

Abstract: A low rotational speed gear module includes a fixed tube member, a rotational sleeve, a first planetary gear set, a sun gear, and a second planetary gear set. The fixed tube member includes a first inner gear. The rotational sleeve includes a second inner gear. The first planetary gear set includes a fixing plate, first planetary gears fixed to one side of the fixing plate, and a driven gear fixed to the other side of the fixing plate. The first planetary gear is engaged at one side with the sun gear and engaged at another side with the first inner gear. The second planetary gear set includes second planetary gears. The second planetary gears is engaged at one side with the driven gear and engaged at another side with the first inner gear and the second inner gear.