A light-weight gear including: an annular tooth portion made of metal; a shaft extending along a central axis of the tooth portion and made of metal; and a coupling element configured to couple the shaft to the tooth portion and made of a resin, in which a joining part between the shaft and the coupling element and a joining part between the tooth portion and the coupling element are provided with irregularities configured to be engaged with one another in a circumferential direction, and corners of the irregularities are rounded to release a stress. Also, provided is a manufacturing method of a light-weight gear including: disposing the tooth portion and the shaft in a mold and injecting a molten resin into a cavity of the mold, thereby simultaneously performing injection molding of the coupling element and joining the coupling element to the tooth portion and the shaft.

An externally toothed gear of a cup-type strain wave gearing has external teeth, the tooth profile of which gradually changes in the tooth-trace direction. The external teeth are formed with an external teeth portion capable of meshing with internal teeth of an internally toothed gear, a first external teeth extension portion and a second external teeth extension portion, in which the first and second external teeth extension portions do not mesh with the internal teeth. The second external teeth extension portion has a narrowing tapered tooth profile so that the second external teeth extension portion serves as a guide when the external teeth is inserted into the internal teeth. The work of assembling the externally toothed gear in the internally toothed gear is made easier.

A speed reduction mechanism and a motor equipped with the speed reduction mechanism are provided. A pinion gear is provided with one spiral engagement projected part, and a helical gear is provided with a plurality of engagement recessed parts with which the engagement projected part is engaged. The engagement projected part and the engagement recessed part are formed so that their cross-sectional shapes along a direction orthogonal to an axial direction of the pinion gear are in arc shapes. A shape of helical teeth and a shape of the engagement recessed part are determined based on a shape of the engagement projected part provided on a spiral tooth.

A speed reduction mechanism and a motor equipped with the speed reduction mechanism are provided. A pinion gear is provided with one spiral engagement projected part, and a helical gear is provided with a plurality of engagement recessed parts with which the engagement projected part is engaged. The engagement projected part and the engagement recessed part are formed so that their cross-sectional shapes along a direction orthogonal to an axial direction of the pinion gear are in arc shapes. A shape of helical teeth and a shape of the engagement recessed part are determined based on a shape of the engagement projected part provided on a spiral tooth.

A reducer for high precision control includes a pin gear housing and two-stage reduction components disposed therein: a first-stage reduction component including an input shaft, a sun gear and a planet gear; and a second-stage reduction component including 2-3 eccentric shafts distributed uniformly, cycloidal gears, a pin, a left rigid disk and a right rigid disk, and bearings, wherein the cycloidal gears are supported by bearings on two eccentric sections of the eccentric shaft, shaft extensions on two sides of the eccentric section of the eccentric shaft are supported by bearings on the left rigid disk and the right rigid disk, and the left rigid disk and the right rigid disk are supported by bearings in inner holes of two sides of the pin gear housing.

A gearing, in particular a coaxial gearing or a linear gearing, comprising a tooth system, a tooth carrier having guides, teeth received within the guides for engagement with the tooth system, wherein the teeth are mounted within the guides to be displaceable in the direction of their longitudinal axis relative to the tooth carrier, a cam disk for driving the teeth along the respective longitudinal axis of the teeth, wherein at least one of the teeth respectively has a tooth flank area having tooth flanks, and a tooth body, wherein, between the tooth body and the tooth flanks, one shoulder respectively is provided, which projects back from the tooth body to the inside towards the tooth flank.

A bicycle sprocket includes a first sprocket body and a plurality of first sprocket teeth. The first sprocket teeth include a plurality of tooth tip portions and a plurality of tooth bottom portions. The tooth bottom portions include at least one first tooth bottom portion and at least one second tooth bottom portion. The at least one first tooth bottom portion has a first tooth bottom shape. The at least one second tooth bottom portion has a second tooth bottom shape. The first tooth bottom shape is different from the second tooth bottom shape.

A bicycle sprocket includes a first sprocket body and a plurality of first sprocket teeth. The first sprocket teeth include a plurality of tooth tip portions and a plurality of tooth bottom portions. The tooth bottom portions include at least one first tooth bottom portion and at least one second tooth bottom portion. The at least one first tooth bottom portion has a first tooth bottom shape. The at least one second tooth bottom portion has a second tooth bottom shape. The first tooth bottom shape is different from the second tooth bottom shape.

The invention is a corner rack with one front face that has teeth. A corner rack is a linear gear interface that can be placed in corners, such that the teeth face out from the corner at an angle, rather than running parallel with the walls. The teeth of the corner rack have a profile that can engage with the profile of a silent chain. The combination of the corner rack and silent chain allows an attached motor to be distanced from the corner rack, so that a lifting device driven by the corner rack and silent chain can be placed in and utilized in corners. This leads to increased versatility and efficiency.

The invention is a corner rack with one front face that has teeth. A corner rack is a linear gear interface that can be placed in corners, such that the teeth face out from the corner at an angle, rather than running parallel with the walls. The teeth of the corner rack have a profile that can engage with the profile of a silent chain. The combination of the corner rack and silent chain allows an attached motor to be distanced from the corner rack, so that a lifting device driven by the corner rack and silent chain can be placed in and utilized in corners. This leads to increased versatility and efficiency.