Infinitely variable transmissions, continuously variable transmissions, methods, assemblies, subassemblies, and components therefor
View Patent ↗Inventive embodiments are directed to components, subassemblies, systems, and/or methods for infinitely variable transmissions (IVT) having a variator provided with a plurality of tilting spherical planets. In one embodiment, a variator is provided with multiple planet arrays. In another embodiment, a hydraulic system is configured to control the transmission ratio of the IVT. Various inventive idler assemblies and planet-pivot arm assemblies can be used to facilitate adjusting the transmission speed ratio of an IVT. Embodiments of a transmission housing and bell housing are adapted to house components of an IVT and, in some embodiments, to cooperate with other components of the IVT to support operation and/or functionality of the IVT. Various related devices include embodiments of, for example, a control feedback mechanism, axial force generation and management mechanisms, a control valve integral with an input shaft, and a rotatable carrier configured to support planet-pivot arm assemblies.
1. A ratio shifting mechanism for a continuously variable transmission having an input shaft and a carrier, the ratio shifting mechanism comprising:
a hydraulic valve adapted to be integral, at least in part, with the input shaft; and
a hydraulic circuit configured to allow a control fluid to flow in and out of the carrier through a plurality of channels and chambers, wherein at least some of the channels and chambers are formed in the input shaft.
2. The ratio shifting mechanism of claim 1 , wherein at least some of the channels and chambers are formed in the carrier.
3. The ratio shifting mechanism of claim 1 , further comprising a control screw operationally coupled to the hydraulic valve.
4. The ratio shifting mechanism of claim 3 , further comprising at least one control screw nut configured to cooperate with the control screw.
5. The ratio shifting mechanism of claim 4 , further comprising a pivot pin hub coupled to the control screw nut.
6. The ratio shifting mechanism of claim 5 , further comprising control pistons adapted to cooperate with the hydraulic valve.
7. The ratio shifting mechanism of claim 6 , wherein the pivot pin hubs are coupled to the control pistons.
8. A method of changing the ratio of a variator of a continuously variable or infinitely variable transmission having a plurality of tiltable planet axles, the method comprising the steps of:
providing a hydraulic control valve;
operably coupling the hydraulic control valve to an input shaft of the transmission;
regulating the hydraulic pressure with the hydraulic control valve;
supplying a hydraulic pressure from the hydraulic control valve through a plurality of channels and chambers in a carrier of the transmission, wherein at least some of the channels and chambers are formed in the input shaft; and
actuating a change in a tilt angle of the planet axles via the hydraulic pressure.
9. The method of claim 8 , further comprising the step of operably coupling the hydraulic control valve to a plurality of hydraulic pistons.
10. The method of claim 9 , further comprising the step of operably coupling the plurality of planet axles to at least one of the plurality of hydraulic pistons.
11. The method of claim 10 , wherein actuating a change in the tilt angle of the planet axles comprises axially translating at least one of the plurality of hydraulic pistons.
12. The method of claim 11 , further comprising the step of providing a pilot pressure to the hydraulic control valve, the pilot pressure configured to indicate a desired tilt angle of the planet axles.
13. The method of claim 12 , wherein providing a pilot pressure comprises configuring a resolution of the pilot pressure to be about 20 psi for every 1 degree of tilt angle.
14. A variator comprising:
an input shaft;
a carrier coupled to the input shaft;
a first plurality of planet-pivot arm assemblies operationally coupled to the carrier;
a first non-rotatable traction ring operationally coupled to the first plurality of planet-pivot arm assemblies;
an output traction ring operationally coupled to the first plurality of planet-pivot arm assemblies;
a ratio shifting mechanism comprising:
a hydraulic valve adapted to be integral, at least in part, with the input shaft; and
a hydraulic circuit configured to allow a control fluid to flow in and out of the carrier through a plurality of channels and chambers, wherein at least some of the channels and chambers are formed in the input shaft.
15. The variator of claim 14 , wherein the carrier is adapted to supply a lubricant to the planet-pivot arm assemblies.
16. The variator of claim 14 , further comprising a torque transfer device operationally coupled to the output traction ring.
17. The variator of claim 16 , further comprising an axial force generating mechanism operationally coupled to the first non-rotatable traction ring.
18. The variator of claim 17 , further comprising a second plurality of planet-pivot arm assemblies coupled to the carrier.
19. The variator of claim 18 , further comprising a second axial force generating mechanism operationally coupled to the output traction ring.
20. The variator of claim 14 , further comprising a control screw operationally coupled to the hydraulic valve.