This invention discloses uninterrupted shifting in transmissions with the use of controlled rotation to achieve desired profile for input to output ratio, thereby eliminating synchronized clutch. Controlled rotation achieved using non-circular gears or Geneva pin and slot wheel mechanism with a customized path for the slot, is used to achieve multiple speed/infinitely variable transmission ratios and/or to transition from one transmission ratio to another. The transition happens over multiple rotations of the input making it highly suited for high torque applications. Since it is not using sprag or one way bearing engine breaking can be achieved. Infinitely Variable Transmission offers steady and uniform output for a steady and uniform input. With co-axial input and output, using planetary gear system, the output can be made continuous from forward to reverse. Multi-Speed uninterrupted shifting is achieved without the need for synchronizers and using a dog clutch or similar device.

A nonlinear closed-loop control combined with an integral time-delay feedback control is disclosed to adjust a speed ratio of an infinitely variable transmission (IVT) system. A speed ratio control for an IVT system involves a forward speed controller and a crank length controller for different speed ranges. The time-delay control is designed to reduce speed fluctuations of the output speed of an IVT with an accurate speed ratio. The speed ratio of an IVT with the disclosed control strategy can achieve an excellent tracking response for the desired constant output speed and reduce speed fluctuations of the output speed of an IVT by the time-delay feedback control.

A nonlinear closed-loop control combined with an integral time-delay feedback control is disclosed to adjust a speed ratio of an infinitely variable transmission (IVT) system. A speed ratio control for an IVT system involves a forward speed controller and a crank length controller for different speed ranges. The time-delay control is designed to reduce speed fluctuations of the output speed of an IVT with an accurate speed ratio. The speed ratio of an IVT with the disclosed control strategy can achieve an excellent tracking response for the desired constant output speed and reduce speed fluctuations of the output speed of an IVT by the time-delay feedback control.

A nonlinear closed-loop control combined with an integral time-delay feedback control is disclosed to adjust a speed ratio of an infinitely variable transmission (IVT) system. A speed ratio control for an IVT system involves a forward speed controller and a crank length controller for different speed ranges. The time-delay control is designed to reduce speed fluctuations of the output speed of an IVT with an accurate speed ratio. The speed ratio of an IVT with the disclosed control strategy can achieve an excellent tracking response for the desired constant output speed and reduce speed fluctuations of the output speed of an IVT by the time-delay feedback control.

A nonlinear closed-loop control combined with an integral time-delay feedback control is disclosed to adjust a speed ratio of an infinitely variable transmission (IVT) system. A speed ratio control for an IVT system involves a forward speed controller and a crank length controller for different speed ranges. The time-delay control is designed to reduce speed fluctuations of the output speed of an IVT with an accurate speed ratio. The speed ratio of an IVT with the disclosed control strategy can achieve an excellent tracking response for the desired constant output speed and reduce speed fluctuations of the output speed of an IVT by the time-delay feedback control.

A planetary gearbox comprises a driving shaft, a plurality of planetary gear train units (PGTUs), a carrier arm disc, a driven shaft and at least one brake assembly. Each of the PGTU further comprises a sun gear, at least one planet gear that is meshed to the sun gear and mounted on a planet axle, a ring gear that is meshed to the planet gear and at least one circular planet carrier arm (CPCA) that is coupled to the planet axle. The driving shaft of the planetary gearbox is coupled to the sun gear of the PGTU thereby causing the sun gear to rotate along with it. Further, the CPCA of the PGTU is coupled to the carrier arm disc and the carrier arm disc is further coupled to the driven shaft.

A positively-engaged infinitely-variable transmission (PE-IVT) system employs a gear assembly including a first helical gear and a second helical gear meshed with the first helical gear. The first helical gear is divided into a plurality of gear segments that can individually move axially along a spline shaft. The PE-IVT system further includes a swashplate configured to constrain the axial motion of the plurality of gear segments. In some embodiments, the system further includes one or more thread-aligners configured to axially align a gear segment with one or more additional gear segments. In some embodiments, the second helical gear is also divided into a plurality of gear segments.

A positively-engaged infinitely-variable transmission (PE-IVT) system employs a gear assembly including a first helical gear and a second helical gear meshed with the first helical gear. The first helical gear is divided into a plurality of gear segments that can individually move axially along a spline shaft. The PE-IVT system further includes a swashplate configured to constrain the axial motion of the plurality of gear segments. In some embodiments, the system further includes one or more thread-aligners configured to axially align a gear segment with one or more additional gear segments. In some embodiments, the second helical gear is also divided into a plurality of gear segments.

A power transmission unit that can prevent unintentional disengagement of a clutch. A first set of teeth formed on an outer circumferential surface of a first rotary member is engaged with a third set of teeth formed on an inner circumferential surface of a second rotary member. A second set of teeth formed on an inner circumferential surface of the first rotary member is meshed with a fourth set of teeth formed on an outer circumferential surface of a third rotary member. A center of engagement between the first set of teeth and the third set of teeth is situated at a point withdrawn from a center of engagement between the second set of teeth and the fourth set of teeth in the direction to disengage the first set of teeth from the third set of teeth.

A power transmission unit that can prevent unintentional disengagement of a clutch. A first set of teeth formed on an outer circumferential surface of a first rotary member is engaged with a third set of teeth formed on an inner circumferential surface of a second rotary member. A second set of teeth formed on an inner circumferential surface of the first rotary member is meshed with a fourth set of teeth formed on an outer circumferential surface of a third rotary member. A center of engagement between the first set of teeth and the third set of teeth is situated at a point withdrawn from a center of engagement between the second set of teeth and the fourth set of teeth in the direction to disengage the first set of teeth from the third set of teeth.