Abstract: Provided is a hollow-type rotary actuator. For example, a rotary actuator used in a joint part of an industrial robot is provided with: a hollow motor having a hollow rotary shaft; a hollow reduction gear having a hollow input shaft that is arranged coaxially with the rotary shaft and is coupled to the rotary shaft; a tubular member disposed on the inner peripheral side of the rotary shaft and the input shaft; and a holding member that holds one end side of the tubular member. The holding member is provided with a holding portion, in which a through-hole communicating with the inner peripheral side of the tubular member is formed. In the rotary actuator, one end side of the tubular member is held by the holding portion, and the other end side of the tubular member is loosely fitted to the output side portion of the hollow reduction gear.

Abstract: Provided is a rotary actuator having a motor and a reduction gear that are arranged coaxially, wherein the weight of the rotary actuator can be reduced. For example, a rotary actuator is provided with: a motor having a rotary shaft and a drive magnet fixed to the rotary shaft; and a reduction gear 8 having an input shaft that is arranged coaxially with the rotary shaft and is coupled to the rotary shaft. The rotary shaft is provided with a cylindrical magnet fixing part, to which the drive magnet is fixed on the outer peripheral side. One end side of the input shaft is fixed to the inner peripheral side of the magnet fixing part. The rotary shaft is formed from a magnetic material, and the input shaft is formed from a material having a lower specific gravity than the magnetic material from which the rotary shaft is formed.