Transmission with power take-off
A method and system for operating a transmission that includes two power take off devices is described. In one example, an internal combustion engine and/or an electric machine may supply power to accessory devices via first and second power take off devices. Alternatively, power may be delivered to the transmission via one or both of the first and second power take off devices.
1. A transmission, comprising:
a first power take off port including a power take off shaft that rotates at a multiple of a rotational rate of a first shaft, the first shaft coupled to a first planetary gear set;
a second shaft configured to deliver power to vehicle wheels, the second shaft coupled to planetary gears of the first planetary gear set; and
a second power take off port, the second power take off port coupled to a sun gear of the first planetary gear set.
2. The transmission of claim 1 , further comprising a first electric machine and a second electric machine.
3. The transmission of claim 2 , further comprising a second planetary gear set and a third planetary gear set.
4. The transmission of claim 3 , further comprising a first clutch configured to decouple the second power take off port from the sun gear of the first planetary gear set.
5. The transmission of claim 4 , further comprising a second clutch configured to decouple a power source from the first shaft.
6. The transmission of claim 5 , where the second shaft is directly coupled to planetary gears of the first planetary gear set.
7. The transmission of claim 1 , where the second power take off port is directly coupled to the sun gear of the first planetary gear set.
8. A method for operating a transmission, comprising:
receiving energy to the transmission, the transmission including a first power take off and a second power take off, the first power take off coupled to a first planetary gear set, the second power take off selectively coupled to the first planetary gear set via a power take off clutch; and
rotating a shaft of the first power take off while rotating a shaft of the second power take off at a different speed than a rotational speed of the first power take off.
9. The method for operating the transmission of claim 8 , where the energy is electric energy, and further comprising:
generating torque via an electric machine in the transmission to rotate the shaft of the second power take off.
10. The method for operating the transmission of claim 8 , where the energy is mechanical energy, the mechanical energy generated via an internal combustion engine.
11. The method for operating the transmission of claim 8 , further comprising closing the power take off clutch and applying two brakes in the transmission to deliver rotational output from the second power take off.
12. The method for operating the transmission of claim 8 , further comprising closing the power take off clutch and applying a first brake and not applying a second brake in the transmission to deliver rotational output from the second power take off.
13. The method for operating the transmission of claim 12 , where the second brake is directly coupled to a carrier of a second planetary gear set.
14. The method for operating the transmission of claim 13 , where the first brake is directly coupled to a ring gear of a third planetary gear set.
15. The method for operating the transmission of claim 8 , further comprising delivering power to vehicle wheels via the transmission while rotating the shaft of the second power take off.
16. A transmission, comprising:
a first power take off port including a power take off shaft that rotates at a multiple of a rotational rate of a first shaft, the first shaft coupled to a first planetary gear set;
a second shaft configured to deliver power to vehicle wheels, the second shaft coupled to planetary gears of the first planetary gear set;
a second power take off port, the second power take off port coupled to a sun gear of the first planetary gear set;
two brakes; and
a controller including executable instructions stored in non-transitory memory that cause the controller to adjust operating states of the two brakes to deliver power via the second power take off.
17. The transmission of claim 16 , where the first of the two brakes is directly coupled to a ring gear of a third planetary gear set.
18. The transmission of claim 17 , where the second of the two brakes is directly coupled to a carrier of a second planetary gear set.
19. The transmission of claim 16 , further comprising additional instructions to adjust an operating state of a clutch to transfer torque from a power source to vehicle wheels.
20. The transmission of claim 16 , further comprising additional instructions to adjust an operating state of a clutch to transfer torque to an accessory device via the second power take off.