Absolute encoder

An absolute encoder comprising:

• a first driving gear, fixed to a spindle, coaxially with the spindle, and configured to rotate according to a rotation of the spindle;
• a first magnet provided on the first driving gear;
• a first driven gear, having a center axis perpendicular to a center axis of the first driving gear, and configured to engage the first driving gear;
• a second driving gear, provided coaxially with the first driven gear, and configured to rotate according to a rotation of the first driven gear;
• and
• a second driven gear, having a center axis perpendicular to the center axis of the first driven gear, and configured to engage the second driving gear, wherein:
• the first driving gear includes:
• a cylindrical portion fit onto a tip end of the spindle, coaxially with the spindle, and
• an annular portion having a teeth portion provided on an outer side of the annular portion in a radial direction,
• the teeth portion is configured to engage the first driven gear,
• the cylindrical portion and the annular portion are physically distinct elements,
• the annular portion is provided coaxially with the spindle and adjacent to the cylindrical portion,
• the annular portion is fit onto the cylindrical portion so that an inner peripheral surface of the annular portion is in contact with an outer peripheral surface of the cylindrical portion,
• an inner peripheral surface of the cylindrical portion is in contact with an outer peripheral surface of the spindle along an axial direction parallel to the spindle from a position below a bottom end of the annular portion toward a top end of the annular portion,
• the inner peripheral surface of the annular portion is in contact with the outer peripheral surface of the cylindrical portion along the axial direction from the bottom end of the annular portion toward the top end of the annular portion, and
• a first length of contact between the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the spindle along the axial direction from the bottom end of the annular portion toward the top end of the annular portion is smaller than a second length of contact between the inner peripheral surface of the annular portion and the outer peripheral surface of the cylindrical portion along the axial direction from the bottom end of the annular portion toward the top end of the annular portion.