To provide a speed changer capable of switching a speed reduction ratio of a speed reduction mechanism unit and thereby preventing a rapid increase in motor temperature to ensure workability even when a motor continues to be used while detected load torque is slightly lower than a predetermined value.
The speed changer includes a motor 1, a speed reduction mechanism unit 2, and a speed reduction ratio switching means. The speed reduction ratio switching means includes a switching actuator 6 for switching a speed reduction ratio, a controller 60 for controlling the switching actuator 6, and a drive state detection unit 68 for detecting an index value representing a load torque applied to the motor 1. The controller 60 performs control to activate the switching actuator 6 in a first case where the index value exceeds a first threshold value, and in a second case where the index value forms a repeated pattern of fluctuation repeated between the first threshold value and a second threshold value different therefrom and the repeated pattern satisfies a predetermined condition.
INAGAKI KENICHIRO
UMIKURA HIROYUKI
ARIMURA SUNAO
YAMADA MINORU
Mizuhiji Katsuhisa
Takeshi Sakaguchi
Hidetoshi Kitade