A planetary transmission (2) includes a stepped planetary gear (24), or planetary gears, which are connected to each other, that is/are disposed radially between a first shaft (6) and axially-adjacent first and second ring gears (12, 16). The stepped planetary gear, or connected planetary gears, include(s) a first gearing region (26) that meshes with a sun gear (8) on the first shaft (6) and the first ring gear (12), as well as a helically-toothed second gearing region (28) that meshes with the second ring gear (16). A cylindrical support region (32) is coaxially provided on/around the first shaft. The stepped planetary gear or the connected planetary gears is/are supported on the cylindrical support region of the first shaft by the outer circumferential surface of the second gearing region. The second gearing region lies on the addendum circle of the second gearing region.

A speed change device includes a sun gear. A plurality of intermediate gears surround the sun gear. Each of the plurality of intermediate gears includes a forward set of teeth and an aft set of teeth. A ring gear surrounds the plurality of intermediate gears. The ring gear includes a forward portion with a forward set of teeth in meshing engagement with the forward set of teeth on each of the plurality of intermediate gears and an aft portion with an aft set of teeth in meshing engagement with the aft set of teeth on each of the plurality of intermediate gears. A carrier includes a carrier forward portion and a carrier aft portion. Each of the plurality of intermediate gears are located axially between the carrier forward portion and the carrier aft portion.

An actuator is provided which includes a stationary frame; an output plate disposed within said stationary frame; a top plate; a stator disposed between said stationary frame and said top plate, said stator describing an annulus; a rotor disposed within the annulus of said stator; a principal bearing disposed between said stationary frame and said output plate; a pinion gear; and a star gear which meshes with said pinion gear.

A ride-on vehicle, such as for a child, includes a vehicle body and one or more wheels that support the vehicle body relative to a surface. At least one of the wheels includes a hub motor arrangement that provides a drive torque for propelling the vehicle. The hub motor arrangement includes a housing defining an interior space. An axle or other mounting element(s) define an axis of rotation of the housing. Preferably, the axle or other mounting element(s) do not pass completely through the housing. A motor drives the housing through a transmission. Preferably, the motor is a standard, compact motor that is positioned on the axis of rotation and can be laterally offset from a central plane of the housing. In some embodiments, a traction element is carried directly by the housing.

A prime mover includes a stator fixed to a housing, and a rotor rotatable relative to the stator. The prime mover outputs torque from the rotor by being supplied with electric power. A speed reducer reduces the torque of the prime mover and outputs the reduced torque. The speed reducer includes a sun gear to which the torque from the rotor is input, and a planetary gear that revolves in a circumferential direction of the sun gear while rotating in a state of meshing with the sun gear. The rotor and the sun gear are formed separately, and are disposed coaxially so as to be integrally rotatable.

Torque of a prime mover is input into a sun gear. A planetary gear revolves in a circumferential direction of the sun gear while rotating and meshing with the sun gear. A carrier has an annular shape, rotatably supports the planetary gear, and is rotatable relative to the sun gear. A first ring gear is fixed to a housing, and meshes with the planetary gear. A second ring gear meshes with the planetary gear, is different from the first ring gear in number of teeth of a tooth portion, and outputs torque to a rotation portion. At least a part of the sun gear in an axial direction is located radially inward of the carrier. At least a part of the first ring gear and at least a part of the second ring gear in the axial direction are located radially outward of the carrier.

A crankshaft system is provided. The crankshaft has a main journal, a rod journal rotates around the main journal, a planet gear is attached to the rod journal and can rotate around the rod journal, the rotation of the planet gear is constrained by a constraining gear, the teeth number of the constraining gear is integer k times of the teeth number of the planet gear, a crankpin is mounted on the planet gear, one end of a connecting rod of a piston is attached to the crankpin, the constraining gear is a ring gear or a sun gear, the trajectory of the crankpin is noncircular. The combustion chamber volume keeps constant from 0° ATDC to 14° ATDC, or the minimum combustion chamber volume extends from TDC to 14° ATDC or after 14° ATDC.

An electrically operated valve having excellent wear resistance while suppressing cost is provided. The electrically operated valve comprises a valve main body having a valve seat; a motor including a stator fixed to the valve main body and a rotor driven to rotate with respect to the stator, a planetary gear type deceleration mechanism configured to decelerate rotation of the rotor to transmit to an output gear, a valve member configured to be movable toward and away from the valve seat in an axial direction, and a feed screw mechanism configured to convert rotational movement of the output gear into movement of the valve member in the axial direction. The planetary gear type deceleration mechanism includes a sun gear coupled to the rotor, a planetary gear engaged with the sun gear, a carrier for rotatably supporting the planetary gear, an annular ring gear engaged with the planetary gear, and a sliding member abutting against an axial end of the sun gear. The output gear has a different number of teeth than the ring gear, and engages with the planetary gear, and the sliding member is made of a different material from the material of the sun gear.

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.

An electrically operated valve having excellent wear resistance while suppressing cost is provided. The electrically operated valve comprises a valve main body having a valve seat; a motor including a stator fixed to the valve main body and a rotor driven to rotate with respect to the stator, a planetary gear type deceleration mechanism configured to decelerate rotation of the rotor to transmit to an output gear, a valve member configured to be movable toward and away from the valve seat in an axial direction, and a feed screw mechanism configured to convert rotational movement of the output gear into movement of the valve member in the axial direction. The planetary gear type deceleration mechanism includes a sun gear coupled to the rotor, a planetary gear engaged with the sun gear, a carrier for rotatably supporting the planetary gear, an annular ring gear engaged with the planetary gear, and a sliding member abutting against an axial end of the sun gear. The output gear has a different number of teeth than the ring gear, and engages with the planetary gear, and the sliding member is made of a different material from the material of the sun gear.