EP-4739525-A1 - ELECTRIC AXLE SYSTEM WITH DIFFERENT GEAR RATIOS

Abstract

The electric axle (e-axle) system having variable gear ratios is disclosed. The e-axle system can include a first axle assembly having one axle gear ratio and a second axle assembly having two or more axle gear ratios that are selectively and independently controlled. In addition, each of the first and second axle assemblies is independently controlled to be in a neutral position.

Inventors

• FALLS, BRUCE
• NECHUSHTAN, ODED

Assignees

• Flyer Next, LLC

Dates

Publication Date

20260513

Application Date

20240626

Claims (20)

1. 1. An axle system for an electric vehicle (EV), comprising: a first axle assembly configured to operate in a first gear ratio; and a second axle assembly configured to selectively operate in a second gear ratio and a third gear ratio, wherein the first gear ratio, the second gear ratio, and the third gear ratio are different ratios, and wherein the first axle assembly and the second axle assembly are configured to operate independently of each other.
2. 2. The axle system of claim 1, wherein the first axle assembly and the second axle assembly are configured to operate in a neutral position, independently of each other.
3. 3. The axle system of claim 2, wherein the first axle assembly is operated in the neutral position while the second axle assembly is operated in the second gear ratio or the third gear ratio.
4. 4. The axle system of claim 2, wherein the second axle assembly is operated in the neutral position while the first axle assembly is operated in the first gear ratio.
5. 5. The axle system of claim 1, wherein: the first axle assembly and the second axle assembly are coupled to a computing system of the vehicle; and the computing system dynamically selects between the second gear ratio and the third gear ratio based on sensing data.
6. 6. The axle system of claim 5, wherein the sensing data comprises: operating conditions including at least one of a speed of the vehicle, an acceleration of the vehicle, a deceleration of the vehicle, or a neutral gear selection; and driving conditions including at least one of a road gradient or a road surface.
7. 7. The axle system of claim 5, wherein the first axle assembly further includes a fourth gear ratio that is different from the first, second, and third gear ratios, wherein the computing system dynamically selects between the first gear ratio, the second gear ratio, and the fourth gear ratio.
8. 8. A vehicle comprising: a first axle assembly configured to operate in a first gear ratio; a second axle assembly configured to selectively operate in a second gear ratio and a third gear ratio; and a computing system configured to: control the first axle assembly and the second axle assembly, and dynamically select between the second gear ratio and the third gear ratio, wherein the first gear ratio, the second gear ratio, and the third gear ratio are different ratios, and wherein the first axle assembly and the second axle assembly are configured to operate independently of each other.
9. 9. The vehicle of claim 8, wherein the first axle assembly and the second axle assembly are configured to operate in a neutral position, independently of each other.
10. 10. The vehicle of claim 9, wherein the first axle assembly is operated in the neutral position while the second axle assembly is operated in the second gear ratio or the third gear ratio.
11. 11. The vehicle of claim 9, wherein the second axle assembly is operated in the neutral position while the first axle assembly is operated in the first gear ratio.
12. 12. The vehicle of claim 8, wherein the computing system is configured to dynamically select between the second gear ratio and the third gear ratio based on sensing data of the vehicle.
13. 13. The vehicle of claim 12, wherein the sensing data comprises: operating conditions including at least one of a speed of the vehicle, an acceleration of the vehicle, a deceleration of the vehicle, or a neutral gear selection; and driving conditions including at least one of a road gradient or a road surface.
14. 14. The vehicle of claim 8, wherein the vehicle is an electric vehicle (EV).
15. 15. A computing system comprising: a memory storing instructions; and one or more processors, coupled to the memory, and configured to dynamically select a first gear ratio and a second gear ratio of a first axle assembly of a vehicle, wherein a second axle assembly of the vehicle has a third gear ratio, wherein the first gear ratio, the second gear ratio, and the third gear ratio are different ratios, and wherein the one or more processors are further configured to control the first axle assembly and the second axle assembly independently of each other.
16. 16. The computing system of claim 15, wherein the one or more processors are further configured to set the first axle assembly and the second axle assembly in a neutral position, independently of the second axle assembly.
17. 17. The computing system of claim 16, wherein the first axle assembly is operated in the neutral position while the second axle assembly is operated in the third gear ratio.
18. 18. The computing system of claim 16, wherein the second axle assembly is operated in the neutral position while the first axle assembly is operated in the first gear ratio or the second gear ratio.
19. 19. The computing system of claim 15, wherein the one or more processors are further configured to dynamically select between the first gear ratio and the second gear ratio based on sensing data.
20. 20. The computing system of claim 19, wherein the sensing data includes: operating conditions including at least one of a speed of the vehicle, an acceleration of the vehicle, a deceleration of the vehicle, or a neutral gear selection; and driving conditions including at least one of a road gradient or a road surface.

Description

ELECTRIC AXLE SYSTEM WITH DIFFERENT GEAR RATIOS CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority to U.S. Application No. 18/346,660, filed July 3, 2023 and titled “ELECTRIC AXLE SYSTEM WITH DIFFERENT GEAR RATIOS,” the disclosure of which is incorporated by reference herein in its entirety. TECHNICAL FIELD [0002] The disclosure relates to the field of electric vehicles. BACKGROUND [0003] As vehicles have come to incorporate electrical technologies to enhance the functionality of vehicle components, axle assemblies having an electric motor (i.e., electric axles) have been increasing in popularity. Such an electric axle or e-axle combines an electric motor and a gear mechanism (e.g., reducer and differential), and generates a rotating torque using electricity. A vehicle axle, whether a conventional axle rotating by an engine or e-axle rotating by a motor, is a central shaft for rotating wheels or gears, and a vehicle generally includes one or more driven axles. For instance, passenger cars (e.g., sedan, SUV, minivan, etc.) have front and rear axles to rotate front and rear wheels, respectively, while larger vehicles (e.g., commercial buses, trucks, trailers, etc.) that carry more passengers/loads and have more wheels may have more than two axles. [0004] E-axles are widely used in vehicles utilizing hybrid/electric power. Vehicles having e-axles generally have one single predetermined gear ratio (i.e., single speed) for all the axles (e.g., front and rear axles). That is, one same ratio is selected for both front and rear e-axles in a vehicle. [0005] An axle ratio or axle gear ratio is a manufacturer-defined value selected according to the vehicle’s specific body style and power source in order to meet specific performance metrics, such as towing strength, efficiency, etc. For example, a higher axle ratio is desirable for quick starts with high torque to begin moving a vehicle, but is undesirable for operation at higher speeds. While the higher axle ratio provides more pulling power, it generally results in a reduction in fuel economy. A lower axle ratio is desirable for highspeed operation, but is undesirable and may be inadequate to initiate vehicle motion. A compromise axle ratio may be selected, but this is only efficient at mid-range speeds. In addition, the compromise gear ratio (e.g., mid-range value) is less efficient at different operating points because the gear ratio is not matched to the operating speed. [0006] In general, vehicles utilizing e-axles do not have a neutral position to disengage the electric motor and/or output gears from the wheels. However, a neutral position is beneficial in certain situations, such as towing, etc. [0007] Thus, it would be desirable to have a multi-ratio drive that would overcome the above disadvantages particularly for all-wheel drive (AWD) vehicles, which independently power the front and rear wheels all the time to provide traction effort. This could be accomplished with multi-ratio e-axles for both the front and the rear drive but this adds mass and cost as a multi-ratio e-axle is more complex multi-ratio. [0008] One solution that can provide the advantages without incurring the additional mass/cost is to use one multi-ratio e-axle and one single speed e-axle with neutral capabilities. The single speed e-axle can have a different gear ratio than the multi-ratio e- axle to allow for increased operating performance in many instances. In addition, it would be advantageous to develop a dual- or multi-axle system that is lightweight, reduces windage and frictional losses, can be operated in a low speed and high torque manner of operation and a high speed and low torque manner of operation, and that can be reconfigured for desired gear ratios without excessively increasing a cost of the drive axle system. Further, a neutral function capability for both front and rear wheels can bring several advantages such as increased efficiency and reduced failure mode consequences. The multi-ratio allows optimizing motor working points in a relatively large range for increased performance and efficiency for both positive and negative torques (e.g., propulsion and regeneration). [0009] Therefore, improved multi-ratio e-axle systems are needed to overcome one or more of the aforementioned shortcomings. BRIEF DESCRIPTION OF THE DRAWINGS [0010] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate aspects of the present disclosure and, together with the description, further serve to explain the principles of the disclosure and to enable a person skilled in the pertinent art to make and use the disclosure. [0011] FIG. 1 shows a vehicle having an electric axle system according to aspects of the disclosure. [0012] FIG. 2 shows an exploded view of a front electric axle assembly according to aspects of the disclosure. [0013] FIG. 3A shows an exploded view of a rear electric axle assembly according to as