A power transmission device includes a pin gear having a plurality of power transmission pins that are relatively moved corresponding to a tooth shape formed on an outer gear, a motor arranged in a direction crossing a rotation axis of the pin gear, and generating power to rotate the pin gear, and a motion transfer unit connected to the pin gear and the motor between the pin gear and the motor, and transferring a rotational motion of the motor to a rotational motion of the pin gear.

A rotary actuator is used in a shift-by-wire system for a vehicle. A speed reducer includes a ring gear and a sun gear and reduces a rotational speed of the motor. An output shaft outputs rotation of the motor at a reduced rotational speed by the speed reducer. A regulating pin is disposed in a fixing member and allows the sun gear to revolve around a rotational axis of the motor and to rotate about an eccentric axis. The regulating pin is a separate member from the fixing member. The regulating pin has a strength equal to or greater than a maximum torque reaction force received from the sun gear. A first difference in hardness between an engaging portion and the sun gear is set to be less than a second difference in hardness between the fixing member and the sun gear.

A rotary actuator is used in a shift-by-wire system for a vehicle. A speed reducer includes a ring gear and a sun gear and reduces a rotational speed of the motor. An output shaft outputs rotation of the motor at a reduced rotational speed by the speed reducer. A regulating pin is disposed in a fixing member and allows the sun gear to revolve around a rotational axis of the motor and to rotate about an eccentric axis. The regulating pin is a separate member from the fixing member. The regulating pin has a strength equal to or greater than a maximum torque reaction force received from the sun gear. A first difference in hardness between an engaging portion and the sun gear is set to be less than a second difference in hardness between the fixing member and the sun gear.

A gear device includes an internal gear, an external gear having flexibility configured to partially mesh with the internal gear and rotate around a rotation axis relatively to the internal gear, and a wave generator configured to come into contact with an inner circumferential surface of the external gear and move a meshing position of the internal gear and the external gear in a circumferential direction around the rotation axis. The external gear includes a cylindrical section including a first end portion with which the wave generator is in contact and a second end portion adjacent to the first end portion along the rotation axis. An inner circumferential surface of the first end portion includes a polished surface. An inner circumferential surface of the second end portion includes a lathe-cut surface.

A load cell for determining a radial force acting on a crankshaft includes a receiving sleeve for receiving a ring of a bearing; a fastening ring for attaching the load cell in a transmission housing; axial support areas provided on the fastening ring for axially supporting the ring of the bearing; and measuring regions for receiving radial forces of the receiving sleeve and which connect the receiving sleeve with the fastening ring, wherein strain sensors are attached to at least two of the measuring regions; and wherein the measuring regions comprise measuring lugs formed as angle brackets.

A swash-plate-type gearing for adjustment devices includes a housing; an outer part, which has an inner toothing concentric with a joint axis; and an inner part with an outer toothing concentric with an eccentric axis, which runs parallel to the joint axis, offset by an off-centre distance. The gearing also includes an engagement region, in which the outer toothing is engaged with the inner toothing and which is located on a straight line intersecting the joint axis and eccentric axis, in each case at a right angle, with the eccentric axis lying on this straight line between the joint axis and engagement region; and a free space located 180° opposite the engagement region and on the straight line, in which free space the outer toothing is disengaged from and at a distance from the inner toothing. A locking part is provided having a locking region located in the free space.

A rotary actuator assembly can include a fluid motor with a rotor that displaces with hypocyclic precessional motion within a stator in response to fluid flow through the fluid motor, and a gear reducer section including an input gear that is fixed relative to the rotor and displaces with the hypocyclic precessional motion relative to an output gear. Another rotary actuator assembly can include a fluid motor with a rotor having a central longitudinal axis that rotates about a central longitudinal axis of a stator, and a gear reducer section including an input gear that rotates with the rotor and displaces relative to an output gear, and the input gear having the same central longitudinal axis as the rotor. A well system can include at least two fluid motors, and fluid flow through one fluid motor causes rotation of the other fluid motor in the well.

A rotary actuator assembly can include a fluid motor with a rotor that displaces with hypocyclic precessional motion within a stator in response to fluid flow through the fluid motor, and a gear reducer section including an input gear that is fixed relative to the rotor and displaces with the hypocyclic precessional motion relative to an output gear. Another rotary actuator assembly can include a fluid motor with a rotor having a central longitudinal axis that rotates about a central longitudinal axis of a stator, and a gear reducer section including an input gear that rotates with the rotor and displaces relative to an output gear, and the input gear having the same central longitudinal axis as the rotor. A well system can include at least two fluid motors, and fluid flow through one fluid motor causes rotation of the other fluid motor in the well.

A rotary actuator includes a motor, a speed reducer configured to output after reducing a rotation of a rotary shaft of the motor, and a housing accommodating the motor and the speed reducer. The rotary actuator includes a bearing having an inner ring fixed to the rotary shaft and rotatably supporting the rotary shaft, and a cylindrical outer ring fixing portion integrally provided on the housing so as to fix an outer ring of the bearing. A front housing has a jig insertion hole into which an inner ring receiving jig can be inserted, and the jig insertion hole has an opening that overlaps with at least a part of one end surface of the inner ring in view from an axial direction.

The present invention provides a transmission mechanism which is suited to miniaturization and can reduce motion transmission errors. This transmission mechanism includes: a cam; a plurality of pins arrayed along a side surface of the cam; guide plates provided with a plurality of guide holes; and a pair of gears disposed so as to sandwich the cam. Each pin contacts only one of the pair of gears, and is guided to the corresponding guide hole in conjunction with the rotation of the cam and moves along the cam and the corresponding gear, thereby causing the guide plates or the pair of gears to rotate with respect to the cam.