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.

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.

A window shade system includes a first bracket coupled to a first pivot and rotatable at least within a first range of angles, a second bracket coupled to a second pivot and rotatable at least within a second range of angles, and first and second gears that each include a circular base rotatable about a central axis. Gear teeth are arranged in a same row and extend outward from the outer region and are evenly spaced from each other along the outer region of the gears. The first and second pivots are arranged relative to each other and relative to the central axes of the first and second gears, respectively, such that for any angle within the first range of angles, the gear tooth of the first gear meshes with the gear tooth of the second gear at a corresponding angle within the second range of angles.

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.

A gear includes a circular base having a front surface that includes an inner region and an outer region that surrounds the inner region. The circular base is rotatable about a central axis. Plural gear teeth are arranged in a same row and extend outward from the outer region of the front surface and are evenly spaced from each other along plural locations on the outer region. Each gear tooth has a cross-sectional width that decreases with decreasing distance from the central axis, and has an outer shape configured to permit any one of the gear teeth in the row to contact and directly mesh with any gear tooth in a corresponding row of gear teeth of a substantially identical gear for any gear angle within a predefined range of gear angles between the central axis of the gear and the central axis of the substantially identical gear.

A driving device in one aspect of the present disclosure includes an electric motor, a worm gear, a gear easing that stores the worm gear, a first fitting portion provided in the electric motor, a second fitting portion provided in the gear casing and fitting to the first fitting portion, and a restriction member that includes a pressure contact portion and a contact portion and restricts displacement of the worm gear along a rotation center axis thereof. The pressure contact portion is in pressure contact with one fitting portion out of the first fitting portion and the second fitting portion, and the contact portion is in contact with the other fitting portion.

A mechanical system for transmitting rotary motion between at least two shafts movable in rotation respectively about a first axis and a second axis, the first and second axes intersecting, the mechanical system including a bevel gear set made up of a first bevel gear having teeth and movable in rotation about the first axis and a bevel wheel having teeth and movable in rotation about the second axis, the teeth of the first bevel gear and of the bevel wheel respectively being suitable for co-operating in complementary manner with one another, the first bevel gear, referred to as a power gear, presenting a first defining pitch surface of conical shape, and the bevel wheel presenting a second defining pitch surface of conical shape.

A gear includes a circular base having a front surface that includes an inner region and an outer region that surrounds the inner region. The circular base is rotatable about a central axis. Plural gear teeth are arranged in a same row and extend outward from the outer region of the front surface and are evenly spaced from each other along plural locations on the outer region. Each gear tooth has a cross-sectional width that decreases with decreasing distance from the central axis, and has an outer shape configured to permit any one of the gear teeth in the row to contact and directly mesh with any gear tooth in a corresponding row of gear teeth of a substantially identical gear for any gear angle within a predefined range of gear angles between the central axis of the gear and the central axis of the substantially identical gear.

A window shade system includes a first bracket coupled to a first pivot and rotatable at least within a first range of angles, a second bracket coupled to a second pivot and rotatable at least within a second range of angles, and first and second gears that each include a circular base rotatable about a central axis. Gear teeth are arranged in a same row and extend outward from the outer region and are evenly spaced from each other along the outer region of the gears. The first and second pivots are arranged relative to each other and relative to the central axes of the first and second gears, respectively, such that for any angle within the first range of angles, the gear tooth of the first gear meshes with the gear tooth of the second gear at a corresponding angle within the second range of angles.

An involute gear bracket system includes first and second involute gears. Each includes a circular base and a plurality of gear teeth extending outward from an outer region of a surface and evenly spaced apart from each other along a plurality of locations on the outer region of the surface. The shape of each gear tooth is defined by a varying cross-sectional involute profile, wherein starting from a first involute profile that is in a plane parallel to the surface of the circular base and extending outward from a center of the circular base, each location on the first involute profile is rotated about a corresponding axis while traversing a path defined by a corresponding imaginary ray extending from the center of the circular base to that location, the corresponding axis being tangential to an imaginary circle that encompasses the inner region of the surface and perpendicular to the corresponding imaginary ray. A first bracket is coupled to a first pivot located at a first distance from the central axis of the first involute gear. A second bracket is coupled to a second pivot and rotatable about the second pivot at least within a second range of angles. The first and second pivots are arranged relative to each other and relative to the central axes of the first and second involute gears, respectively, such that the gear tooth of the first involute gear meshes with the gear tooth of the second involute gear at a corresponding angle within a second range of angles.