EP-4737765-A1 - TRANSMISSION ARRANGEMENT WITH A CLUTCH CONCENTRIC TO A DIFFERENTIAL GEAR ARRANGEMENT

EP4737765A1EP 4737765 A1EP4737765 A1EP 4737765A1EP-4737765-A1

Abstract

The present disclosure relates to a transmission arrangement comprising an input shaft configured to be connected to an electric traction motor, a first countershaft and a second countershaft, each of the first and second countershafts being drivingly connected to the input shaft, wherein each of the first and second countershafts comprises a respective first and second countershaft gearwheel, a differential gear arrangement connected to an output shaft of the transmission arrangement, and a clutch arranged concentrically to the differential gear arrangement, wherein the transmission arrangement is configured to assume a first gear state in which the clutch connects the first countershaft gearwheel of each of the first and second countershafts to the differential gear arrangement, and a second gear state in which the clutch connects the second countershaft gearwheel of each of the first and second countershafts to the differential gear arrangement.

Inventors

LIEBERUM, Nicholas
BRANDT, Richard S
SKINNER, SEAN
LAMBERTUS, ZACHARY

Assignees

Volvo Truck Corporation

Dates

Publication Date: 20260506
Application Date: 20241104

Claims (15)

A transmission arrangement (100) for an electrically propelled vehicle, the transmission arrangement comprising: - an input shaft (102) configured to be connected to an electric traction motor (20), - a first countershaft (200) and a second countershaft (300), each of the first and second countershafts being drivingly connected to the input shaft, wherein each of the first and second countershafts comprises a respective first (202, 302) and second (204, 304) countershaft gearwheel, - a differential gear arrangement (400) connected to an output shaft (104) of the transmission arrangement, and - a clutch (600) arranged concentrically to the differential gear arrangement, wherein the transmission arrangement (100) is configured to assume a first gear state in which the clutch connects the first countershaft gearwheel of each of the first and second countershafts to the differential gear arrangement, and a second gear state in which the clutch connects the second countershaft gearwheel of each of the first and second countershafts to the differential gear arrangement.
The transmission arrangement of claim 1, wherein the transmission arrangement is further configured to assume a neutral gear state in which the clutch is disconnected from both of the first and second countershaft gearwheels of the first and second countershafts.
The transmission arrangement of any one of claims 1 or 2, wherein the input shaft comprises an input shaft gearwheel connected to each of the first and second countershafts.
The transmission arrangement of claim 3, wherein each of the first and second countershaft comprises a gearwheel arranged in meshing engagement with the input shaft gearwheel.
The transmission arrangement of claim 4, wherein the meshing engagement between the input shaft gearwheel and the gearwheels of the first and second countershaft form a respective reduction gear state.
The transmission arrangement of any one of claims 3 - 5, wherein the input shaft gearwheel is press-fitted to the input shaft.
The transmission arrangement of any one of the preceding claims, wherein the first gear state has a higher speed reduction to the output shaft compared to the speed reduction of the second gear state.
The transmission arrangement of any one of the preceding claims, wherein the second countershaft gearwheel of the first countershaft is integrally formed with the first countershaft.
The transmission arrangement of any one of the preceding claims, wherein the second countershaft gearwheel of the second countershaft is integrally formed with the second countershaft.
The transmission arrangement of any one of the preceding claims, wherein the differential gear arrangement comprises a differential gearwheel connectable to each the first and second countershaft gearwheels of the first and second countershafts via the clutch.
The transmission arrangement of any one of the preceding claims, wherein the clutch is a single clutch.
A driveline comprising a transmission arrangement according to any one of the preceding claims, and an electric traction motor connected to the input shaft of the transmission arrangement.
The driveline of claim 12, wherein the electric traction motor is coaxial to the output shaft.
The driveline of any one of claims 12 or 13, further comprising a driveline housing, the electric traction motor and the transmission arrangement being arranged inside the housing.
A vehicle comprising a driveline according to any one of claims 12 - 14.

Description

TECHNICAL FIELD The disclosure relates generally to transmission arrangements. In particular aspects, the disclosure relates to a transmission arrangement with a clutch concentric to a differential gear arrangement. The disclosure can be applied to heavy-duty vehicles, such as trucks, buses, and construction equipment, among other vehicle types. Although the disclosure may be described with respect to a particular vehicle, the disclosure is not restricted to any particular vehicle. BACKGROUND Propulsion systems for vehicles are continuously developed to meet the demands from the market. A particular aspect relates to the emission of environmentally harmful exhaust gases. Therefore, vehicles propelled by electric traction motors have been increasingly popular, both for cars as well as for heavy duty vehicles. A transmission may conventionally be connected to the electric traction motor. There is however a desire to further improve such transmissions in relation to complexity and power ratio, especially for transmissions arranged in connection to a differential gear arrangement of the vehicle. SUMMARY According to a first aspect of the disclosure, there is provided a transmission arrangement for an electrically propelled vehicle, the transmission arrangement comprising: an input shaft configured to be connected to an electric traction motor, a first countershaft and a second countershaft, each of the first and second countershafts being drivingly connected to the input shaft, wherein each of the first and second countershafts comprises a respective first and second countershaft gearwheel, a differential gear arrangement connected to an output shaft of the transmission arrangement, and a clutch arranged concentrically to the differential gear arrangement, wherein the transmission arrangement is configured to assume a first gear state in which the clutch connects the first countershaft gearwheel of each of the first and second countershafts to the differential gear arrangement, and a second gear state in which the clutch connects the second countershaft gearwheel of each of the first and second countershafts to the differential gear arrangement. The first aspect of the disclosure may seek to provide a simple and less bulky transmission arrangement for a differential gear arrangement which can enable for a continuous and relatively high torque to the wheels of the vehicle. A technical benefit may include that the transmission arrangement can be switched between two gear states, while still obtaining a sufficient and relatively high peak torque. By providing two gear states, a less complex transmission arrangement can be provided. Also, arranging the clutch concentric to the differential gear arrangement and using the clutch to simultaneously engage e.g. the first countershaft gear wheel of each of the first and second countershafts to the differential gear arrangement, a higher torque can be provided to the differential gear arrangement compared to the use of a single countershaft. In detail, a torque load is acting on the differential gear arrangement from two countershafts simultaneously. Further, by using a two-gear state transmission arrangement, a continuous power flow to the wheels may be obtained, i.e. the transmission arrangement may enable for a solution which is substantially free from torque interruption when switching gears. The wording "drivingly connected to" should be construed as two components being connected to each other such that when a first one of the components rotates, the second component also rotates. The two components may be directly connected to each other, or connected to each other via e.g. a third component. Optionally in some examples, including in at least one preferred example, the transmission arrangement is further configured to assume a neutral gear state in which the clutch is disconnected from both of the first and second countershaft gearwheels of the first and second countershafts. A technical benefit may include that solely the differential gear arrangement rotates when the transmission arrangement assumes the neutral gear state. Hence, the differential gear arrangement rotates along with the rotation of the wheels but the first and second countershafts, as well as the input shaft may be maintained stationary or at least not rotating along with the rotation of the wheels. Hereby, there may be substantially no rotation of gearwheels and the efficiency may thus be improved. There may also be no need of providing a relatively high weight and costly hub disconnect functionality to the transmission arrangement. Optionally in some examples, including in at least one preferred example, the input shaft comprises an input shaft gearwheel connected to each of the first and second countershafts. A technical benefit may include that a gear stage can be provided between the input shaft and the first countershaft as well as between the input shaft and the second countershaft. Optiona