Integrated Electric Axle Layout for Low-Floor Vehicle Access
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Solution Overview
Problem
There is a need for an electric axle assembly that minimizes floor height in low floor vehicles, such as buses and people carriers, to facilitate easier ingress and egress, particularly for disabled passengers and those with strollers, while incorporating electric propulsion systems for increased performance and efficiency.
Innovation Solution
The electric axle assembly includes a suspension frame, drive assemblies with electric drive units and drive trains housed in cases, a drive module with a sealed enclosure containing a drive circuit, and interconnects for power, control signals, and cooling fluid delivery, along with isolation mounts to dampen forces, allowing for compact and sealed operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If drivetrain components are relocated to reduce intrusions into the vehicle floor, then floor height is minimized for easier passenger ingress and egress, but the complexity of the axle assembly increases
Solution Approach 1:
The patent combines the drive module, drive assemblies, suspension frame, and cooling system into an integrated electric axle assembly. The drive module housing serves as both structural support and containment for electrical components, while the suspension frame integrates both mechanical support and cooling fluid pathways. This merging reduces the number of separate components and simplifies installation despite the advanced functionality.
Solution Approach 2:
The suspension frame serves multiple functions: it provides structural support for the drive components, acts as a cooling fluid distribution system with integrated pathways, and serves as the mounting structure for the drive module. The drive module housing similarly provides both mechanical mounting and electrical component containment. This multi-functionality reduces the need for additional separate components.
2Reliability
If a sealed enclosure is used to protect the drive circuit, then reliability is improved by preventing contamination, but manufacturing complexity increases
Solution Approach 1:
The drive module is housed in a separate sealed enclosure that can be manufactured and tested independently before final assembly into the axle assembly. This segmentation allows the enclosure to be produced using standard sealing techniques and quality control procedures, making the sealing process more manageable and reliable while not significantly increasing overall manufacturing complexity.
3Reliability
If isolation mounts are used to dampen forces, then the drive module is protected from vibration and shock, but the device complexity increases
Solution Approach 1:
The isolation mounts are integrated directly into the suspension frame structure rather than being separate add-on components. The suspension frame includes built-in mounting points and structural features that incorporate the isolation function, combining the suspension and isolation functions into a single integrated structure. This reduces the number of separate parts while maintaining the vibration and shock protection functionality.
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
This configuration enables a low floor vehicle with reduced intrusions, improved mobility, and efficient electric propulsion, enhancing passenger access and vehicle performance by providing motive force while maintaining a low profile and allowing for easy maintenance.
Implementation Method 1
a biasing member arranged between the support tabs and configured to bias the support tabs away from one another
Data Source
AI summary
An electric axle assembly includes a suspension frame, a pair of drive assemblies coupled to opposite sides of the suspension frame, and a drive module coupled to the suspension frame. The drive module controls operation of the drive assemblies. The electric axle assembly is mounted to a vehicle frame and provides motive force to wheels of the vehicle for propelling the vehicle along a roadway.