Gear devices and methods for operating gear devices are provided. In one example, a gear device is provided that comprises structures designed to attenuate targeted vibrations occurring during rotation of the gear device. The structures includes radially aligned struts extending between an inner carrier and an outer carrier, a plurality of openings arranged between the struts, and/or resonators extending between sequential struts.

An anti-backlash structure for a scissors gear is provided including a scissors gear and a cam gear which are coaxially connected to rotate relative to each other, an end piece which has one side which is press-fitted into a cam shaft so that the end piece rotates together with the cam shaft, the other side which is in surface-to-surface contact with the scissors gear, and a circumferential surface with which the cam gear is press-fitted; a bolt which is coupled to an inner diameter portion of the scissors gear, penetrates the end piece, and is inserted into the cam shaft; and a scissors spring which has one side coupled to the end piece, and the other side coupled to the bolt. When the end piece rotates, the scissors spring rotates the scissors gear relative to the cam gear through the bolt and allows the scissors gear to come into close contact with the cam gear.

Power takeoff devices (PTOs) are useful for mounting on transmissions and for performing, directly or indirectly, useful work via the mechanical energy generated by the PTO's rotatable output shaft. Systems and methods for reducing PTO gear rattle include an input gear carried on a shaft sleeve mounted on a shaft extending between opposing spaced apart walls of a PTO housing. The shaft sleeve is moveable in an axial direction along the shaft, the travel of the shaft sleeve in each direction being limited by contacting the respective wall. The shaft sleeve is biased to remain spaced apart from the walls, thereby reducing or eliminating gear rattle.

A gas turbine engine according to an example of the present disclosure includes, among other things, a fan section, a compressor section, and a turbine section including a fan drive turbine that drives the fan through a gear reduction. The gear reduction includes at least two double helical gears in meshed engagement, each of the at least two double helical gears having a first plurality of gear teeth separated from a second plurality of gear teeth such that a first end of the first plurality of gear teeth and a first end of the second plurality of gear teeth are spaced apart by an axial distance. Each of the first plurality of gear teeth is offset a first circumferential offset distance in relation to the next gear tooth of the second plurality of gear teeth when moving in a circumferential direction relative to respective axes.

A drive device for a motor vehicle includes an electrical machine which is operatively connected to a transmission device via a drive shaft. The transmission device has at least a first and a second planetary stage and a differential stage. Each planetary stage includes a planet set having a plurality of planet gears, the planet gears being rotatably arranged on a planet carrier and meshing with a sun gear and with a ring gear. The second ring gear has external teeth which mesh with internal teeth of a ring gear cup fixed to a housing in a stationary manner.

A gear mechanism for a fishing reel includes a drive gear, a handle, and a vibration damper. The drive gear includes a gear having a prescribed gear diameter, and a drive gear shaft rotated together with the gear and having a smaller dimension than the prescribed gear diameter. The handle rotates the drive gear shaft. The vibration damper is disposed between the drive gear shaft and the handle, and dampens the transmission of the vibration of the drive gear.

In a transmission apparatus for a saddle-type vehicle, dowels on first transmission gears are engageable in and disengageable from dowel holes in adjacent second transmission gears to shift gear positions. The first transmission gears are slidable in response to angular movement of a shift spindle caused by operating a shift pedal. Invalid engagement time, during which the dowels and dowel columns are in sliding abutment, at an idling engine rotational speed is in the range from 0 msec. to 40 msec., providing an enhanced feeling for gear shifting operations and reduce hammering noise.

A planetary gear system can include a sun gear, an outer ring gear, and at least one planet gear driving the sun gear and planet gear. The planet gear can include an inner ring having an inner race, an outer ring having an outer race circumscribing and confronting the inner race. A plurality of rolling elements can be located between and in contact with the inner and outer races, which can include least one damper.

Provided is a vehicle transmission for a gear shift operation. The vehicle transmission includes: a shift lever which is at least partially displaced toward front or rear directions by a driver to select shift stages; a movable plate which includes an input shaft rotated according to the displacement of the shift lever and an internal gear; an eccentric gear unit which has a first external gear eccentrically engaged with the internal gear and a second external gear moved simultaneously with the first external gear; a rotation unit having a ring gear with which the second external gear is eccentrically engaged; and an insertion unit which includes an eccentric shaft inserted into an aperture formed at a center of the eccentric gear unit and a central shaft formed with the eccentric shaft and inserted into an aperture formed at a center of the rotation unit.

A strain wave gearing has a rigid internally toothed gear, a flexible externally toothed gear, and a sliding-contact type wave generator. The wave generator has: a plurality of gear pressing members that flexes the externally toothed gear in the radial direction at positions at equal angular intervals in the circumferential direction to form plurality of meshing portions which mesh with the internally toothed gear; and piezoelectric elements that generate ultrasonic vibration of 20 kHz to 80 kHz in the gear pressing members in the radial direction. Ultrasonic vibration is applied at contact sites where the gear pressing members and the externally toothed gear contact each other. As a result of a squeeze film effect, the apparent friction coefficient of each contact surface at the contact sites can be greatly reduced and rotational torque, of the wave generator can be reduced.