Abstract: An electric rotation device rotating a rotation target member by torque outputted to an output member includes: a motor; a reduction gear mechanism including transmission gears transmitting torque from the motor to the output member; a rotational position detection gear including a tooth width different from that of a predetermined gear among the transmission gears, and meshing with the predetermined gear; a rotational position detection sensor outputting a signal corresponding to a rotational position of the rotational position detection gear, and detecting a rotational position of the rotation target member; a visual recognition portion configured to distinguish a reference tooth of one gear from the other tooth of the one gear; and a groove filling portion filling a tooth groove of the other gear, the groove filling portion filling a portion of the tooth groove not overlapping the one gear in a radial direction.

Abstract: An electric opening and closing device that opens and closes a toilet seat or lid by a torque output to an output member includes: a motor; a reduction gear mechanism having gear members including a gear member of a spur tooth and transmitting the torque of the motor to the output member; and a torque limiter that includes a first rotating member rotating integrally with a first gear member rotating by the torque among the gear members, a second rotating member rotating integrally with a second gear member connected to the output member via the gear member of the spur tooth or the output member, and a friction member engaged with one of the first and second rotating members, and that generates a slip between the friction and other rotating members to interrupt the transmission of the torque when a torque exceeding a value acts on the output member.

Abstract: An electric rotation device rotating a rotation target member by torque outputted to an output member includes: a motor; a reduction gear mechanism including transmission gears transmitting torque from the motor to the output member; a rotational position detection gear including a tooth width different from that of a predetermined gear among the transmission gears, and meshing with the predetermined gear; a rotational position detection sensor outputting a signal corresponding to a rotational position of the rotational position detection gear, and detecting a rotational position of the rotation target member; a visual recognition portion configured to distinguish a reference tooth of one gear from the other tooth of the one gear; and a groove filling portion filling a tooth groove of the other gear, the groove filling portion filling a portion of the tooth groove not overlapping the one gear in a radial direction.

Abstract: An electric opening and closing device that opens and closes a toilet seat or lid by a torque output to an output member includes: a motor; a reduction gear mechanism having gear members including a gear member of a spur tooth and transmitting the torque of the motor to the output member; and a torque limiter that includes a first rotating member rotating integrally with a first gear member rotating by the torque among the gear members, a second rotating member rotating integrally with a second gear member connected to the output member via the gear member of the spur tooth or the output member, and a friction member engaged with one of the first and second rotating members, and that generates a slip between the friction and other rotating members to interrupt the transmission of the torque when a torque exceeding a value acts on the output member.