Ball type continuously variable transmission
View Patent ↗A variable transmission includes an input shaft, a planetary gear set drivingly engaged with a variator comprising, a variator carrier assembly, a first ring assembly, and a second ring assembly; and the output shaft, arranged to produce transmissions with continuously variable or infinitely variable output ratios.
1. A variable transmission comprising:
an input shaft;
a variator (CVP) comprising a first ring assembly coupled to the input shaft, a carrier assembly comprising a plurality of tiltable variator balls drivingly engaged with the first ring assembly, and a second ring assembly drivingly engaged with the tiltable variator balls; and
a first planetary gearset comprising a planet carrier drivingly engaged with the input shaft, a ring gear drivingly engaged with the second ring assembly of the variator, and a sun gear drivingly engaged with an output,
wherein the planetary gearset is configured to split power of the input shaft between the variator and a mechanical path going directly to the output through the planetary gear set.
2. The variable transmission of claim 1 , wherein the first ring assembly and the second ring assembly are drivingly coupled over a continuous range of speed ratios from a minimum speed ratio to a maximum speed ratio, and wherein the speed ratio is controlled by the tiltable variator balls.
3. The variable transmission of claim 1 , wherein the tiltable variator balls control a first speed ratio between the first ring assembly and second ring assembly of the variator, and thereby controls a second speed ratio between the planet carrier and ring gear of the first planetary gearset.
4. The variable transmission of claim 1 , wherein a minimum speed ratio and a maximum speed ratio between the input shaft and the sun gear of the first planetary gearset span a range from negative to positive.
5. The variable transmission of claim 1 , further comprising a damper coupled to the input shaft and disposed between a power source and the variable transmission.
6. The variable transmission of claim 5 , further comprising a clutch disposed between the power source and the variable transmission.
7. The variable transmission of claim 6 , wherein the clutch is coupled to the damper or at a location to allow interrupting power transmission.
8. The variable transmission of claim 1 , further comprising a first speed ratio shifter configured to shift a first range of speed ratios to higher or lower values.
9. The variable transmission of claim 8 , wherein the first speed ratio shifter comprises a countershaft and gear drivingly engaged with the first ring assembly, the countershaft and gear having a gear ratio that shifts a first speed ratio between the input shaft and the second ring assembly.
10. The variable transmission of claim 8 , wherein the first speed ratio shifter comprises the first planetary gearset, a portion of which is grounded.
11. The variable transmission of claim 8 , wherein shifting the first range of speed ratios to higher values shifts a second range of speed ratios between the planet carrier and sun gear of the first planetary gearset to lower values.
12. The variable transmission of claim 8 , wherein the first range of speed ratios between the input shaft and the sun gear or output spans a negative ratio to a positive ratio.
13. The variable transmission of claim 12 , wherein the first range of speed ratios between the input shaft and the sun gear or output spans a negative ratio to a positive ratio, the negative ratio having equal magnitude as the positive ratio.
14. The variable transmission of claim 1 , wherein the variator is an asymmetric variator.
15. The variable transmission of claim 14 , wherein the asymmetric variator performs the function of a speed ratio shifter.
16. The variable transmission of claim 14 , wherein the first ring assembly comprises a first ring assembly engagement portion that is drivingly engaged with the tiltable variator balls, and the second ring assembly comprises a second ring assembly engagement portion that is drivingly engaged with the tiltable variator balls, and wherein the first ring assembly engagement portion is offset from the second ring assembly engagement portion such that a speed ratio is greater than 1 or less than 1 when the tiltable variator balls are not tilted.
17. The variable transmission of claim 8 , further comprising a second speed ratio shifter configured to shift a third range of speed ratios to higher or lower values.
18. The variable transmission of claim 17 , wherein the second speed ratio shifter comprises a second planetary gear set comprising a second sun gear, a second ring gear and a second gear, one of which is grounded to create a speed ratio.
19. The variable transmission of claim 18 , wherein two of the second sun gear, the second ring gear, and the second gear, are not grounded and are connected to the input shaft and the first ring assembly.
20. The variable transmission of claim 17 , wherein shifting the third range of speed ratios to higher values shifts a second range of speed ratios between the planet carrier and sun gear of the first planetary gearset to lower values.
21. The variable transmission of claim 17 , wherein the third range of speed ratios between the input shaft and the sun gear or output spans a negative ratio to a positive ratio.
22. The variable transmission of claim 17 , wherein the third range of speed ratios between the input shaft and the sun gear or output spans a negative ratio to a positive ratio, the negative ratio having equal magnitude as the positive ratio.