The flexible external gear of a strain wave gearing is provided with: a cylindrical body part capable of flexing in the radial direction; external teeth formed on the outer circumferential surface thereof with a constant pitch; and grooves formed on the inner circumferential surface of the cylindrical body section along the circumferential direction thereof with the same pitch as the external teeth. The grooves are grooves with a wave-shaped cross-sectional shape having the center line of the tooth crest of the external tooth as the center and extend in the width direction of the external teeth. It is possible to increase the tooth bottom fatigue strength of the flexible external gear by increasing the tooth bottom thickness, while maintaining ease of flexing and a tooth shape that can withstand tangential forces due to meshing.

A robot includes a first member, a second member provided rotatably with respect to the first member, a gearing that transmits drive power from one side to the other side of the first member and the second member, the gearing includes an internal gear, an external gear having a flexible barrel portion in a tubular shape with an opening portion in an end part, and rotating about a rotation axis relative to the internal gear, and a wave generator, the wave generator includes a cam having a non-circular outer circumferential surface, and a bearing including an inner ring, an outer ring, and a plurality of balls, the first member includes a counter body provided to face the end part on the opening portion side of the barrel portion, and a first seal member is provided between the outer ring and the counter body.

In a strain wave gearing, the addendum tooth profile of an inner gear is defined by a formula and that of an outer gear is by another formula at a principal cross-section located at a tooth-trace-direction center of the outer gear, on the basis of a movement locus (Mc) of =1 by the teeth of the outer gear with respect to those of the inner gear. The tooth profiles of the dedenda of each of the inner gear and the outer gear are set to any shape that does not interfere with the tooth profile of the addendum of the other gear. It is possible to avoid superimposed flexion-induced bending stresses and tensile stresses caused by load torque arising at the long-axis locations of the outer gear, and the transmission torque capacity of a strain wave gearing can be improved.

The flexible gearwheel disc is configured for a high-reduction gear mechanism that has at least two gearwheel segments which are arranged next to one another in the circumferential direction of the gearwheel disc and are connected to one another by means of spring segments. The gear mechanism includes a flexible gearwheel with at least two flexible gearwheel discs. The flexible gearwheel, at the same time makes increased flexibility of the gearwheel discs or of the gearwheel in the radial direction and an increased rigidity in the circumferential direction possible. The spring segments run obliquely with respect to the circumferential direction of the gearwheel disc.

The present disclosure discloses a harmonic reducer with conjugate cycloidal profiles, including a circular spline, a flexspline, a wave generator and a flexible bearing. A profile of the circular spline and a profile of the flexspline are conjugate cycloidal profiles. The profile of the circular spline and the profile of the flexspline are formed by hypocycloids and epicycloids formed by two rolling circles around a pitch circle of the circular spline and a pitch circle of the flexspline under an engaging state respectively. A sum of radii of the first rolling circle and the second rolling circle is equal to a difference between radii of the pitch circle of the circular spline and the pitch circle of the flexspline under the engaging state. The wave generator is a biarc cam wave generator, a cam curve is an arc within an angle of contact in the long axis direction.

The invention relates to a strain wave gear, having an outer ring with an inner toothing, with which a flexible inner ring with an outer toothing engages at two opposing points. The strain wave gear is characterized in that the ratio of the pitch diameter of the outer ring to the rim thickness of the outer ring lies in the region of 13 to 21, especially in the region of 17 to 19, especially at 17.587, wherein the teeth of the toothing of the inner ring have a profile angle in the region of 8 degrees to 15 degrees or in the region of 11 degrees to 12 degrees or one of 11.615 degrees, and/or wherein the teeth of the toothing of the outer ring have a profile angle in the region of 8 degrees to 15 degrees or in the region of 11 degrees to 13 degrees or one of 12.474 degrees.

The dedendum tooth profiles of the internal teeth and external teeth of a strain wave gearing are prescribed by a first homothetic curve BC and a second homothetic curve AC obtained from a curve segment from a point A, at which the angle formed by the tangent to a movement locus Mc when meshing is approximated by rack meshing and the major axis is A, to a low point B. The dedendum tooth profile of the internal teeth is prescribed by a curve formed on the internal teeth in the course of the addendum tooth profile of the external teeth moving from an apex of the movement locus to point A. The dedendum tooth profile of the external teeth is prescribed by a curve formed on the external teeth when the addendum tooth profile of the internal teeth moves from the apex to arrive at point A.

Provided is a plate harmonic reducer, and more particularly, a plate harmonic reducer, in which design may be further simplified and a manufacturing cost may be reduced.

A strain wave gearing includes a rigid internally toothed gear, a flexible externally toothed gear disposed coaxially within the internally toothed gear, and a wave generator fitted within the externally toothed gear. The internally toothed gear and the externally toothed gear are spur gears having module m; and the number of teeth of the externally toothed gear is 2n less than the number of teeth of the internally toothed gear, where n is a positive integer. Taking a transverse cross-section at a prescribed position along a tooth trace direction of the external teeth as a main cross-section, a degree of flexing, with respect to a rim-neutral circle of the externally toothed gear prior to ellipsoidal flexing, of a rim-neutral line of the ellipsoidally flexed externally toothed gear is set, at a position on the major axis in the main cross-section, to 2mn.

A method for manufacturing a flexible externally toothed gear includes: a first step (ST1) for producing a primary molded article by performing near-net-shape plastic working on a material comprising a nickel-free low-alloy steel having a silicon content of 1.45-1.5 wt %; a second step (ST2) for martempering the primary molded article; a third step (ST3) for producing a secondary molded article from the primary molded article; and a fourth step (ST4) for shot-peening the secondary molded article to change the surface portions of the tooth part and other parts to martensite. A flexible externally toothed gear can be obtained in which the surface hardness is kept within a prescribed range and the fatigue strength and abrasion resistance are high.