A joint apparatus for a robot includes a housing, a bearing including an inner ring and an outer ring contacting the housing, a rotating member contacting the inner ring of the bearing, and a driving apparatus configured to rotate the rotating member, where the first housing includes a first support region configured to support a front surface of the outer ring and a first fastening region extending rearward from the first support region and on which a first thread is formed, the sounding housing includes a second support region configured to support a rear surface of the outer ring and a second fastening region extending forward from the second support region and on which a second thread is formed, and the second thread is configured to engage the first thread.

An annular body includes a base, a first resistance wire, a second resistance wire, a first terminal, and a second terminal. The base surrounds a central axis and expands in a direction intersecting the central axis. Resistance values of the first and second resistance wires change according to strain of the base. The first terminal is electrically connected to the end of the first resistance wire. The second terminal is electrically connected to an end of the second resistance wire. The first terminal is at a first position in the circumferential direction. The second terminal is at a second position in the circumferential direction. When viewed in the axial direction, the central angle defined by the first position, the central axis, and the second position is equal to or greater than about 90°.

This gear wheel mechanism includes a rotator, a first gear wheel, a second gear wheel, and a reinforcement member. The rotator is configured to be rotatable about a rotation shaft and has an elliptical shape as viewed in an axis direction of the rotation shaft. The first gear wheel includes a first base portion including a first outer circumferential surface and a first inner circumferential surface and having a hollow cylindrical shape configured to be deformable by the rotator being inserted in the axis direction of the rotation shaft and external teeth formed in the outer circumferential surface. The second gear wheel includes a second base portion including a second outer circumferential surface and a second inner circumferential surface and having a hollow cylindrical shape disposed to cover the external teeth and internal teeth which are formed at positions facing the external teeth of the second inner circumferential surface, with which the external teeth are partially engaged in accordance with deformation of the first base portion by rotation of the rotator. The reinforcement member is disposed in contact with a region of the second outer circumferential surface corresponding to a region in which the internal teeth of the second inner circumferential surface are formed.

A cup-type strain wave gearing having a unit structure and having: a stationary-side part including a unit housing and an internally toothed gear; a driving-side part including an output member and an externally toothed gear; and a sliding bearing supporting the stationary-side part and the driving-side part in the radial direction and the thrust direction in a state in which relative rotation is possible. The sliding bearing has a cylindrical bushing accommodated in a radial gap, and annular bushings accommodated respectively in thrust gaps. Thus, it is possible to provide an advantageous strain wave gearing having a unit structure that is more lightweight and compact than when a rolling bearing is used.

When a strain wave gearing is used in an application for an operation of repeating startup/stopping, an outer-side lubrication portion and an inner-side lubrication portion, which are lubricated using different types of grease, remain in a communicating state without being divided using a seal member or the like. The outer-side lubrication portion is supplied with a much smaller amount of grease than the amount that would be required if used in an application such as a steady operation. Similarly, the inner-side lubrication portion is also supplied with a much smaller amount of grease than the amount that would be required if used in an application such as a steady operation. Essentially, the outer-side lubrication portion and the inner-side lubrication portion can be lubricated appropriately using different types of grease, without the grease becoming mixed.

Provided is a magnetic gear which has a large transmission torque, stability, and a simple structure. A magnetic gear (30) includes: a first magnetic pole array (34) that includes first N poles (35) and first S poles (36) alternately arranged on an outer peripheral inclined surface (32) of a rotary disc (31); a second magnetic pole array (37) that includes second N poles (38) and second S poles (39) alternately arranged on the outer peripheral inclined surface (32), one of the second N poles (38) is positioned at a location corresponding to an intermediate position between a corresponding one of the first N poles (35) and a corresponding one of the second S poles (36) that are adjacent to each other.

Provided is a magnetic gear which has a large transmission torque, stability, and a simple structure. A magnetic gear (30) includes: a first magnetic pole array (34) that includes first N poles (35) and first S poles (36) alternately arranged on an outer peripheral inclined surface (32) of a rotary disc (31); a second magnetic pole array (37) that includes second N poles (38) and second S poles (39) alternately arranged on the outer peripheral inclined surface (32), one of the second N poles (38) is positioned at a location corresponding to an intermediate position between a corresponding one of the first N poles (35) and a corresponding one of the second S poles (36) that are adjacent to each other.

A harmonic gear device includes a rigid internal gear, a flexible external gear and a wave generator. The rigid internal gear is an annular component having internal teeth. The flexible external gear is an annular component, which has external teeth and is configured on an inner side of the rigid internal gear. The wave generator is configured on an inner side of the flexible external gear, and deflects the flexible external gear. The harmonic gear device deforms the flexible external gear along with the rotation of the wave generator taking a rotation axis as the center, such that some of the external teeth mesh with some of the internal teeth. The flexible external gear rotates relative to the rigid internal gear in accordance with the difference between the numbers of teeth of the flexible external gear and the rigid internal gear.

A harmonic drive including a housing component (4) and a drive element (18) which is held on the housing component, can be deformed by a wave generator (14), is in the form of a flanged bushing and has a toothing region (17) having a cylindrical basic shape and a disc section (19) which adjoins the toothing region (17). Adjoining the disc section (19) there is a bushing section (20) which is concentric to the toothing region (17), overlaps the latter in the axial direction and is held interlockingly between a cylindrical edge section (21), which is thick-walled in comparison with the bushing section (20), of the housing component (4) and an intrinsically rigid component (22) which is likewise solid in comparison with the flanged bushing (18).

A driving device includes a motor, a wave gear device including a wave generator having first thickness, a flex spline, and a circular spline having thickness larger than the first thickness, a housing functioning as a housing of the motor and including a flange, and an oil seal fixed to the inner side of the flange and extending along the outer circumference of the shaft. The wave generator is set closer to the opposite direction of the flange to configure an internal space with the members. When the internal space is filled with grease, a distance between the oil seal and the wave generator is set smaller than distances among the other members.