A planetary gear is disclosed that provides at least a first hollow wheel with a helical gearing and a second hollow wheel with a helical gearing are adapted to rotate in a first rotational direction and a second opposite rotational direction, and a first double planet having a first wheel with a helical gearing meshing with the helical gearing of the first hollow wheel and having a second wheel with a helical gearing meshing with the helical gearing of the second hollow wheel. The disclosed configuration minimizes backlash between the helical gearings.

A balanced speed reducer of a dual-ring gear variable-line-speed planetary row includes a dual-ring gear variable-line-speed planetary row, an input end (6), an output end (7), a locking end (8), and auxiliary devices such as bearings. The dual-ring gear planetary row includes a left ring gear (1), a right ring gear (2), and a planet carrier (3). A left planetary gear (4) and a right planetary gear (5) that are connected on each planetary gear shaft have the same rotation speed. The left planetary gear (4) meshes with the left ring gear (1), and the right planetary gear (5) meshes with the right ring gear (2). The number of gear sets is not less than two. A teeth number combination and a number of gear sets are set according to a range specifying parameter and following a principle of matching the teeth number combination with the number of gear sets. A rule for manufacturing and assembling planetary gears is executed. A regulation on gear reference circle radii is executed. By connecting the planetary carrier (3) to the input end (6), connecting one ring gear to the output end (7), and connecting the other ring gear to the locking end (8), a speed reducer that has a corresponding left transmission ratio and right transmission ratio, can be actually assembled and provides balanced operation is formed.

A torsional vibration damper in which noise and vibrations in a planetary gear unit are suppressed is provided. In a planetary gear unit, as an inertial element is oscillated to establish an inertial torque by a relative rotation between a sun gear and a ring gear. Pinion gears are interposed between the sun gear and the ring gear at predetermined intervals, and gear dimensions of one of the pinion gears and gear dimensions of another one of the pinion gears are different from each other.

The planetary gear unit in which sliding resistance between a double helical gear and a peripheral member is reduced is provided. The planetary gear unit comprises: pinion gears individually having two rows of oppositely-oriented helical gears in an axial direction; a first pushing member that elastically pushes at least one of the pinion gears toward in a predetermined axial direction; and a second pushing member that elastically pushes at least one of the remaining pinion gears in the opposite axial direction.

A planetary gear transmission has a sun gear, a ring gear, at least one first planet gear, and at least one second planet gear. The first planet gear and the second planet gear are arranged on a planet carrier, and the sun gear, the ring gear, the first planet gear, and the second planet gear mesh with one another. The planetary gear transmission is characterized in that the planet carrier has a first planet carrier part and a second planet carrier part. The first planet carrier part and the second planet carrier part are designed such that the planet carrier parts are rotated relative to each other starting from a base position and can be fixed in their respective rotated position relative to each other, wherein the at least one first planet gear is connected to the first planet carrier part, and the at least one second planet gear is connected to the second planet carrier part.

A planet gear housing assembly is disclosed in an epicyclical gear system of a gas turbine engine. The planet gear housing assembly comprises an aft planet carrier assembly, a forward planet carrier assembly, and a plurality of planet gears. The planet gear housing assembly includes one or more of the following features: a stiffening member positioned between the forward and aft planet carrier assemblies, a static curvic joint coupling the forward and aft planet carrier assemblies, a plurality of roller element bearings to carry the plurality of planet gears, and one or more bearing springs disposed between a bearing and a carrier housing to accommodate relative movement.

A speed reducer according to one embodiment of the present invention includes a crankshaft and a speed reducing mechanism. The crankshaft includes a gear portion driven by rotation from a drive source and a journal portion formed integrally with the gear portion. The crankshaft rotates about an axis of the journal portion. The speed reducing mechanism decelerates rotation of the crankshaft and outputs the decelerated rotation.

A reduction drive assembly includes a planetary gear assembly. The planetary gear assembly includes a first gear carrier that includes a first plate and projections extending therefrom. The first plate defines first support openings. The planetary gear assembly includes a second gear carrier that defines second support openings and joint openings. The joint openings receive the projections to couple the first and second gear carriers. The planetary gear assembly includes a sun gear coupled to an output shaft and disposed between the first and second gear carriers. The planetary gear assembly includes planet gears disposed around the sun gear between the first and second gear carriers. Each of the planet gears has a carrier pin. Each carrier pin is received by one of the first support openings and one of the second support openings to retain the planet gears between the first and second gear carriers.

An engine variable camshaft timing (VCT) phaser assembly is equipped in an internal combustion engine (ICE) to adjust the rotation of the engine's camshaft relative to the engine's crankshaft. The adjustments advance and retard the opening and closing movements of the engine's intake and exhaust valves. An electric motor and a planetary gear set work together amid use of the VCT phaser assembly. The planetary gear set can include two or more ring gears, planet gears, and a sun gear. A backlash condition sometimes experienced in previous VCTs is minimized in the VCT phaser assembly by one or more springs that urge the planet gears into engagement with the ring gears.

A transmission system of a decelerating mechanism includes a planetary gear unit including a sun gear being adjacent to the first surface and a planetary gear set and a holder including a carrier and several planetary shaft units rotatably disposed on the carrier. The carrier has a first surface and a second surface that face opposite directions. The planetary gear set has several first gears being adjacent to the first surface, respectively fitting around the planetary shaft units, and meshing with the sun gear, several second gears being adjacent to the second surface and being coaxially disposed with the first gears, and an internal gear ring meshing with the second gears. By respectively arranging the first gears and the second gears on two opposite sides of the carrier, mutual interference therebetween while turning could be avoided, and an overall volume of the transmission system could be reduced.