A winch includes a motor having a motor housing including a motor case and an integrated first drum support attached to the motor case for closing an end of the motor case. The tone ring has a protective layer which enables it to withstand the combination of extreme heat and harsh environmental conditions to which it is exposed during operation of the vehicle. The critical points are isolated in the reciprocal state and corresponding critical energies of the critical points are determined. The density converted characteristic information generating section generates density converted characteristic information. At the outer edge of the spacer pieces is provided a wall which mates with the identical wall on an adjacent spacer piece.