A gear device includes an internal gear, an external gear, and a wave generator. The external gear includes a cylinder section, a diaphragm, and a boss section. The diaphragm includes a first coupling section, a second coupling section, and a diaphragm main body. A ratio of the length from one opening end of the cylinder section to the surface of the diaphragm on the opposite side of the opening end in a rotation axis direction to the length from the inner circumferential surface of the boss section coupled to the second coupling section to the outer circumferential surface of the cylinder section in the radial direction is 1.0 or more and 5.0 or less, and t(C)≥t(A), where t(A) represents the thickness of the inner circumferential end of the diaphragm and t(C) represents the thickness of the outer circumferential end.

A lightweight, compact electric drive unit provides high reduction ratios for a bicycle, light electric vehicle or autonomous device. A cycloid gear reducer includes one or more cycloid gears within a housing. The cycloid gears interact with gear teeth on the inside surface of the housing, and ride on a cam shaft having eccentric lobes. Output pins extend through apertures in the cycloid gears, from an input carrier to an output carrier. An electric motor powers the cam shaft, while the output carrier powers a drive train.

A strain wave gear has a wave generator rotatably mounted in a radially flexible sleeve having external toothing, a first rigid hollow wheel with internal toothing meshing with the external toothing of the radially flexible sleeve, and a second rigid hollow wheel with internal toothing meshing with the external toothing of the radially flexible sleeve. The wave generator is mounted by exactly one radially flexible roller bearing so as to be rotatable relative to the radially flexible sleeve. The roller bearing has a first rolling-element row, having first rolling elements, and at least one second rolling-element row, having second rolling elements, that is axially offset from the first rolling-element row. The roller bearing has an external ring with which the first and second rolling elements are in direct contact, and/or an internal ring with which the first and second rolling elements are in direct contact.

A timepiece mechanism including a magnetic gear formed of a first wheel and a second wheel, the first wheel being provided with first alternating magnetic poles forming a magnetic toothing and the second wheel being provided with a toothing made of ferromagnetic material which has a magnetic coupling with the magnetic toothing, such that, when one of the first or second wheels is driven in rotation, this wheel rolls, via the magnetic coupling, over a geometric circle centred on the other wheel and linked to this other wheel. The magnetic gear further includes a ferromagnetic element arranged relative to the first wheel so as to offset at least most of a magnetic disturbance torque to which the first wheel is subjected, resulting from the magnetic coupling, this magnetic disturbance torque having a periodic variation in intensity according to the angular position of the first wheel.

A derailleur includes a fixed component, a movable component, a linkage component, a deceleration component and a drive component. The fixed component is for being fixed to a bicycle frame. The movable component is for being fixed to a chain guide. The linkage component includes a first linkage and a second linkage. Two ends of the first linkage pivot on the fixed component and the movable component, respectively. Two ends of the second linkage pivot on the fixed component and the movable component, respectively. The deceleration component includes a circular spline, a flex spline and a wave generator. The flex spline is disposed inside the circular spline, for rotating the first linkage and the second linkage relative to the fixed component. The wave generator is disposed inside the flex spline. The drive component is connected to the wave generator, for rotating the wave generator.

A bending meshing type gear device includes a wave generator, an external gear that is bent and deformed by the wave generator, an internal gear that meshes with the external gear, and a wave generator bearing disposed between the wave generator and the external gear, in which an inner ring rolling surface on which a rolling element of the wave generator bearing rolls includes a hardened layer, and the hardened layer has a characteristic that a surface hardness after operating for a predetermined time is increased compared to a surface hardness before operation.

An actuator system including a harmonic drive operable to drive a variable vane system of a gas turbine engine.

An actuator system including a harmonic drive operable to drive a variable vane system of a gas turbine engine.

An actuator system including a harmonic drive operable to drive a variable vane system of a gas turbine engine.

A robot includes a base, a first arm that is provided to be rotatable with respect to the base, and a gear device that transmits a driving force from the base to the first arm. The gear device has a flexible gear. The flexible gear has a cylindrical body portion and a bottom portion that is connected to one end portion of the body portion. The bottom portion has a metal flow radially extending from a center side to an outer peripheral side of the bottom portion.