Interaxle Differential Clutch Actuation for Axle Slip Control
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Solution Overview
Problem
Vehicle drivetrains experience drive axle slip in tandem axles due to limitations in interaxle differential (IAD) locking and lubrication systems, leading to wear, improper engagement, and torque spikes that can cause component degradation.
Innovation Solution
A drivetrain system with an IAD featuring a friction clutch actuated by an electric motor and a non-backdrivable planetary gearset, which reduces torque requirements for locking and unlocks efficiently, combined with a lubrication system that routes lubricant efficiently through a supply passage to high-wear areas, reducing system complexity and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex lubricant routing passages are integrated into shafts, then lubrication coverage is improved, but flow losses increase and system degradation likelihood increases
Solution Approach 1:
The patent extracts the lubrication function from the complex integrated shaft passages and implements it as a separate, dedicated lubrication system with its own pump and routing. This separation allows for optimized lubricant delivery to high-wear areas without the flow losses and complexity of integrated passages, while still providing comprehensive lubrication coverage.
2Adaptability or versatility
If a friction clutch with ball ramp actuator is used, then the window of IAD locking functionality is expanded, but device complexity increases
Solution Approach 1:
The patent employs a dynamic clutch pack design with multiple friction plates and a ball ramp actuator that can progressively engage and disengage. This dynamic system allows for gradual locking and unlocking operations, expanding the window of functionality while managing complexity through controlled, staged engagement rather than simple binary locking.
3Force
If a planetary gearset is used as a torque multiplier, then the torque required for clutch actuation is reduced, but the device complexity increases
Solution Approach 1:
The patent introduces a planetary gearset as an intermediary mechanical advantage device between the electric motor and the clutch actuation system. The gearset multiplies the motor's torque output, allowing a smaller, more efficient motor to achieve the required clutch actuation force. This intermediary mechanism reduces overall system complexity compared to using a larger motor directly.
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 system enhances vehicle traction, increases IAD efficiency, and extends component longevity by expanding the window of locking functionality and conserving energy during clutch engagement, while minimizing wear and torque spikes.
Implementation Method 1
A drivetrain system with an IAD featuring a friction clutch actuated by an electric motor and a non-backdrivable planetary gearset, which reduces torque requirements for locking
Implementation Method 2
The clutch plates are transitioned into engagement in response to receiving rotational input from the planetary gearset. While the friction clutch remains engaged, the clutch prevents speed differentiation between a first axle differential and a second axle differential
Implementation Method 3
IADs may further include lubrication systems to reduce component wear and increase IAD longevity. The lubricant is routed via passages integrated into various shafts in the IAD
Data Source
AI summary
Drivetrain systems and methods are provided. In one example, the drivetrain system includes an interaxle differential (IAD) configured to receive power from a prime mover, a motor configured to drive a planetary gearset, and a ball ramp actuator configured to selectively engage a plurality of plates in a clutch pack of a friction clutch in response to receiving rotational input from the planetary gearset. In an engaged configuration, the friction clutch prevents speed differentiation between a first IAD output and a second IAD output.