Multi-speed hybrid transmission and transmission operating method
A hybrid transmission system with a multi-speed gearbox. The multi-speed gearbox, in one example, includes a first primary shaft with a first set of gears positioned thereon and selectively coupled to an internal combustion engine (ICE) at a first end and a second primary shaft with a second set of gears positioned thereon. The gearbox further includes a secondary shaft with a third set of gears that mesh with the first set of gear and the second set of gears and an electric drive interface gear that is idly mounted, free to spin, on the second primary shaft, positioned between two gears in the second set of gears, and configured to receive mechanical power from an electric machine and an output shaft that is configured to mechanically attached to a differential.
1 . A hybrid transmission system, comprising:
a multi-speed gearbox including:
a first primary shaft with a first set of gears positioned thereon and selectively coupled to an internal combustion engine (ICE) at a first end;
a second primary shaft with a second set of gears positioned thereon;
a secondary shaft with a third set of gears that mesh with the first set of gear and the second set of gears;
an electric drive interface gear idly mounted, free to spin, on the second primary shaft, positioned between two gears in the second set of gears, and configured to receive mechanical power from an electric machine;
a gear clutch coupled to the secondary shaft and designed to selectively engage a gear that is idly mounted to the secondary shaft and meshes with the electric drive interface gear; and
an output shaft that includes:
a first output shaft gear which is fixedly coupled thereto meshes with a gear on a secondary shaft; and
a second output shaft gear which meshes with a bevel gear in a differential that is positioned perpendicular to the electric machine.
2 . The hybrid transmission system of claim 1 , further comprising:
an electric drive clutch designed to operate in:
an engaged position where mechanical power is transferred from the electric machine to a gear in the second set of gears via the electric drive interface gear; and
a disengaged position where mechanical power is transferred from the electric machine to a gear in a third set of gears via the electric drive interface gear.
3 . The hybrid transmission system of claim 2 , wherein the electric drive clutch and a gear clutch are arranged in a similar axial position along the second primary shaft and the secondary shaft, respectively and wherein the gear clutch is coupled to the secondary shaft and selectively coupled to a gear in the third set of gears.
4 . The hybrid transmission system of claim 2 , wherein the electric drive clutch is a synchronizer, a dog clutch, or a sliding sleeve clutch.
5 . The hybrid transmission system of claim 1 , further comprising a dual-clutch assembly designed to selectively couple the ICE to the first primary shaft and the second primary shaft.
6 . The hybrid transmission system of claim 1 , wherein the electric drive interface gear is included in a dual gear unit with a second gear that meshes with a gear in a third set of gears.
7 . The hybrid transmission system of claim 1 , further comprising a mechanical reverse assembly coupled to the secondary shaft, wherein the mechanical reverse assembly comprises:
a reverse clutch and a reverse gear set configured to selectively rotationally couple the reverse gear set to the first primary shaft and the secondary shaft.
8 . The hybrid transmission system of claim 1 , further comprising a park lock assembly coupled to the output shaft that is coupled to the differential.
9 . The hybrid transmission system of claim 1 , wherein the multi-speed gearbox includes four or more operating gear ratios.
10 . The hybrid transmission system of claim 1 , wherein the hybrid transmission system is a transaxle.