Internally Cooled Electric Drive Axle for High-Torque Work Vehicles
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Solution Overview
Problem
Large work vehicles require high torque drives for off-road terrain and heavy-duty operations, which are typically powered by conventional diesel engines, but electrification is needed to reduce emissions, requiring complex and costly redesign of vehicle platforms.
Innovation Solution
An electric drive axle with internal cooling, featuring a self-contained system that includes wheel drives, battery packs, and power electronics, which can fit within existing platforms or replace conventional axles, providing structural support and efficient cooling through a coolant circuit with manifold and valve control to manage temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional diesel engines are used to power work vehicles, then high torque and tractive forces are achieved, but emissions increase and environmental harm worsens
Solution Approach 1:
The patent replaces the conventional diesel engine mechanical power system with an electric power train system consisting of battery packs, power controllers, and electric motors. This substitution eliminates tailpipe emissions while maintaining the high torque capability needed for off-road work vehicles, directly resolving the contradiction between reducing harmful emissions and preserving power output.
2Object-generated harmful factors
If electric power trains are integrated into work vehicles, then emissions are reduced, but vehicle platform complexity and redesign costs increase
Solution Approach 1:
The patent segments the electric power train into modular components (battery packs, power controllers, motor assemblies) that can be independently installed and configured. This modular segmentation allows the electric system to be integrated into existing work vehicle platforms without requiring complete platform redesign, thereby reducing complexity and conversion costs while maintaining emission reduction benefits.
Solution Approach 2:
The patent designs the electric power train components to serve multiple functions: the axle housing serves as both structural support and mounting platform for electric components; the cooling system serves both the motor and battery pack; the control system manages multiple functions including motor control and thermal management. This multi-functionality reduces the number of separate systems needed, simplifying platform integration.
3Temperature
If cooling systems are added to electric drive axles, then component temperatures are controlled, but system complexity and space requirements increase
Solution Approach 1:
The patent merges the cooling system for the electric motor and power electronics into a single integrated thermal management system. The coolant circuit serves multiple components (motor housing, power controller) through a unified network of channels and manifolds, reducing the number of separate cooling systems needed and simplifying overall system complexity while maintaining effective temperature control.
Solution Approach 2:
The patent implements nested cooling channels within the motor housing and power controller structures. The coolant flow paths are embedded within the existing component geometries, allowing the cooling system to be integrated within the available space without requiring additional external cooling components, thereby controlling temperature while minimizing space and complexity increases.
4Volume of moving object
If battery packs and power electronics are mounted within the axle housing, then space efficiency is improved, but internal space for cooling and component placement is reduced
Solution Approach 1:
The patent utilizes three-dimensional space within the axle housing by mounting battery packs and power electronics on vertical surfaces and utilizing the depth dimension of the housing. Components are arranged in multiple levels and planes, maximizing space utilization while leaving adequate volume for coolant flow paths and thermal management infrastructure.
Solution Approach 2:
The patent applies different spatial arrangements to different components based on their specific requirements: battery packs are positioned to optimize thermal contact with cooling channels, power electronics are mounted on surfaces with adequate airflow, and high-heat-generating components are placed near coolant inlets. This localized optimization allows efficient space utilization while maintaining adequate cooling volume for each component.
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
Enables the conversion of work vehicles to electric power trains by replacing axle assemblies and integrating battery packs and power electronics, optimizing cooling to maintain component temperatures within safe ranges, thus reducing emissions and operational costs while maintaining performance.
Implementation Method 1
Plumbing lines within the axle housing are configured to convey a coolant from the inlet to the battery pack and the power controller and from the battery pack and the power controller to the outlet
Implementation Method 2
a bypass valve is configured to control flow through the bypass channel. The power controller is configured to change a state of the bypass valve to permit flow from the outlet manifold to the inlet manifold through the bypass channel in response to a temperature of the battery pack falling below a battery operating temperature threshold
Implementation Method 3
The electric drive axle may further include a pump within the axle housing configured to induce flow through the bypass channel
Data Source
AI summary
An electric drive axle for a work vehicle has an axle housing configured to mount to the work vehicle chassis. The axle housing defines an interior cavity disposed between opposite ends defining openings. Wheel end units are secured at least partially within the axle housing, each wheel end unit defining a hub for engaging a ground-engaging member of the work vehicle through one of the openings. Each wheel end unit has drive components configured to rotate the hub of a wheel end unit. A battery pack and power controller are mounted within the axle housing between the wheel end units. The power controller is electrically coupled to the wheel end units and the battery pack to control power to the wheel end units. Plumbing lines within the axle housing convey a coolant from a housing inlet to the battery pack and the power controller and from the battery pack and the power controller to a housing outlet.