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 harmonic reducer includes a shaft having a first through hole extending from a first end to a second end of the shaft; a wave generator arranged on the shaft and being rotatable along with the shaft; a flexible spline arranged around the wave generator; a circular spline arranged around the flexible spline; a first flange coupled to the shaft via a first bearing and coupled to the flexible spline; and a second flange coupled to the shaft via a second bearing and coupled to the circular spline. One of the flanges is arranged near to the first end of the shaft. A cavity is provided between the one of the flanges and the first end of the shaft, such that it is in fluid communication with an external environment via the first through hole.

A gear device includes a first gear, and a second gear meshing with the first gear. At least the first gear is made of a resin. The gear device further includes a connection member connected to an external member, a path member disposed in a path leading to the first gear and the connection member, and other members that are members other than the first gear, the second gear, the connection member, and the path member, and are made of a resin. The first gear, the connection member, and the path member are made of a resin having a higher thermal conductivity than a thermal conductivity of the other members.

A joint actuator of a robot including a driving device, a driving shaft, a reducer, a torsion sensor, and a dual encoder is provided. The driving shaft is connected to the driving device. The driving device is configured to drive the driving shaft to rotate. The reducer includes a motive power input component and a motive power output component. The motive power input component and the motive power output component are sleeved on the driving shaft. The motive power input component is disposed between the driving shaft and the motive power output component. The torsion sensor is connected to the motive power output component of the reducer. The dual encoder is connected to the driving device and the driving shaft. The driving device is located between the dual encoder and the reducer.

An external gear includes a body, external teeth, a diaphragm, and a strain gauge. The diaphragm extends in a direction intersecting with an axial direction on another side in of the body the axial direction. The strain gauge is on at least one of a surface on one side of the diaphragm in the axial direction and a surface on another side of the diaphragm in the axial direction. The strain gauge is only in a region that is about a half or less of a radial length from one end of the diaphragm in the axial direction to the other end of the diaphragm in the axial direction with a radial midpoint between the one end of the diaphragm in the axial direction and the other end of the diaphragm in the axial direction as a center in a section passing through the central axis.

A robot joint structure includes a first robot member, a second robot member, and a speed reducer incorporated in a joint portion that connects the first robot member and the second robot member to each other. The speed reducer includes an external gear, an internal gear that meshes with the external gear, and a fixing member that is provided so as to be non-rotatable relative to the internal gear and is fixed to the first robot member. The fixing member is fixed to the first robot member by bringing an inner peripheral surface of the first robot member and an outer peripheral surface of the fixing member into pressure contact with each other by fastening using a first fastening member. At least a part of an axial range of the first fastening member does not overlap internal teeth of the internal gear when viewed in a radial direction.

A joint shaft structure includes: a base member; an output shaft member supported on one side of the base member so as to be rotatable; and a strain wave gear reducer rotating the shaft member relative to the base member by transmitting rotation of a motor to the shaft member while reducing the speed of the rotation. The reducer includes: a wave generator fixed to a shaft rotated by a driving force from the motor; a flexspline having, at one end, an elastic part which includes a plurality of external teeth and inside which the generator is fitted; and a ring gear disposed on a radially outer side of the flexspline and fixed to the shaft member, and having internal teeth meshing with the external teeth. The flexspline is fixed to the base member at the other end disposed farther on the base member side than the elastic part.

A braking assembly for a strain wave gearing of a surgical robotic manipulator, the braking assembly including a first braking member fixedly coupled to an input portion of a strain wave gearing of a surgical robotic manipulator; and a second braking member fixedly coupled to an output portion of the strain wave gearing, and wherein during a braking operation the first braking member contacts the second braking member to mechanically brake the input portion to the output portion.

An actuator unit (1) includes a direct drive motor (2), a first magnetic gear (3) connected to a rotating shaft (6) of the direct drive motor (2), a second magnetic gear (4) configured to be magnetically engaged with the first magnetic gear (3), and a planetary reducer (5) connected to a rotating shaft of the second magnetic gear (4).

An arm joint is provided with a first coupling part with a first axis and a second coupling part with a second axis. Further, the arm joint includes a third coupling part connected in a manner rotatable around a third axis with the first coupling part. The third axis includes an angle with the first axis in the range of 30-60 degrees, preferably of 45 degrees. The third coupling part is connected in a manner rotatable around a fourth axis with the second coupling part. The fourth axis includes an angle with the second axis in the range of 30-60 degrees, preferably of 45 degrees. The third and the fourth axis mutually include an angle in the range of 60-120 degrees, preferably of 90 degrees. A robot arm with a number, preferably three, of such arm joints is also disclosed.