Compact Axle Assembly With Offset Drive Pinion for High Torque
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Solution Overview
Problem
Existing electric motor-driven axles in hybrid electric vehicles are often oversized for operational requirements, leading to space inefficiencies and design constraints, especially in multi-axle vehicle configurations.
Innovation Solution
A compact axle assembly design that includes an axle housing, a differential assembly, and a drive pinion with a gear reduction module, where the drive pinion is configured to flank the axle shaft and engage the differential assembly, allowing for a more compact and efficient torque transmission system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If large electric motors are used to meet torque requirements, then torque capability is improved, but the motor size increases and encroaches on usable space
Solution Approach 1:
The drivetrain is segmented into separate functional modules: an electric motor, a multi-speed transmission, and a differential assembly. This segmentation allows each component to be optimized independently, enabling the use of a smaller motor that can operate at higher speeds while the transmission provides the necessary torque multiplication through its gear sets.
Solution Approach 2:
A multi-speed transmission acts as an intermediary between the electric motor and the differential assembly. The transmission includes a first gear set for speed reduction and a second gear set for additional torque multiplication, allowing the motor to operate at optimal speeds while delivering the required torque to the wheels.
2Force
If large electric motors are used to meet torque requirements, then torque capability is improved, but the motor footprint increases causing design constraints
Solution Approach 1:
The drivetrain is segmented into separate functional modules: an electric motor, a multi-speed transmission, and a differential assembly. This segmentation allows each component to be optimized independently, enabling the use of a smaller motor that can operate at higher speeds while the transmission provides the necessary torque multiplication through its gear sets.
Solution Approach 2:
The transmission system provides dynamic gear ratio changes, allowing the motor to operate at optimal speeds across different vehicle operating conditions. The first and second gear sets enable the system to adapt torque and speed requirements dynamically, reducing the need for an oversized motor that would be required to handle peak torque demands alone.
3Force
If traditional axle assembly designs are used, then torque transmission is achieved, but space efficiency is reduced and wheel end reduction is required
Solution Approach 1:
The drive pinion is positioned to flank the axle shaft in a lateral direction rather than at the traditional wheel end location. This dimensional repositioning allows torque to be transmitted to the differential assembly through a compact arrangement that eliminates the need for additional reduction gears at the wheel ends, improving space efficiency within the axle housing.
Solution Approach 2:
The drive pinion is integrated directly with the differential assembly, merging the torque transmission function with the differential function. This consolidation eliminates the need for separate wheel end reduction mechanisms and allows for a more compact overall design where the drive pinion engages the differential case to provide both torque multiplication and differential action.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The compact axle assembly design enables a more efficient use of space, reduces the need for wheel end reduction, and allows for higher power densities by utilizing smaller diameter bearings and optimized gear ratios.
Implementation Method 1
a gear reduction module that operatively connects the drive pinion to the electric motor, the gear reduction module transmits torque from the electric motor to the differential assembly at a reduced speed
Data Source
AI summary
In implementations, a method includes receiving a torque that is provided along a first axis at a first portion of the axle assembly that is forward of an axle axis along which at least one axis of the axle assembly is receivable. In addition, the method includes transmitting the torque from the first axis to a second axis that is parallelly offset from the first axis, each of the first and second axes being angled relative to the axle axis. The method includes engaging a differential assembly at a second portion of the axle assembly that is opposite the first portion to thereby provide the torque to one or more traction wheel assemblies that are operatively connected to the axle assembly.