Active Torque Biasing Differential Using Magnetorheological Fluid
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Solution Overview
Problem
Current torque biasing differentials face limitations such as complexity, size, weight, wear, and inefficiency due to clutch packs and the need for external pumping of magnetorheological fluids, which restrict their compatibility with active traction enhancement and electronic stability control systems.
Innovation Solution
An active torque biasing differential utilizing a housing with an outer and inner annulus, where vanes with orifices are slidably contacting and an electromagnetic coil applies a magnetic field to a chamber containing magnetorheological fluid, allowing dynamic viscosity adjustment and torque biasing without external pumping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clutch packs are used to transfer torque through the differential, then torque biasing is achieved, but the device effectiveness declines as the clutch packs wear and the device is subject to chatter
Solution Approach 1:
The patent replaces the mechanical clutch pack system with a magnetorheological fluid-based torque transfer mechanism. The magnetorheological fluid changes its viscosity in response to a magnetic field generated by an electromagnetic coil, enabling torque biasing without mechanical contact between clutch plates. This eliminates wear-related degradation and chatter while maintaining torque transfer effectiveness throughout the service life of the differential.
2Reliability
If magnetorheological fluid is pumped through external structures, then torque biasing is achieved, but the system size and complexity increase and fluid degradation accelerates
Solution Approach 1:
The patent extracts and eliminates the external pumping system from the torque biasing mechanism. Instead of pumping magnetorheological fluid through external tubes and structures, the fluid is contained within the differential housing and its viscosity is modulated in-place by an electromagnetic coil. This reduces system complexity, eliminates pump-related failure points, and prevents fluid degradation from pumping while maintaining effective torque biasing.
3Reliability
If a fixed ratio torque bias differential is used, then torque biasing is provided, but the torque bias ratio cannot be altered without physically modifying the differential, limiting effectiveness in active control systems
Solution Approach 1:
The patent transforms the fixed-ratio torque bias differential into a dynamic, adjustable system. By using an electromagnetic coil to generate a magnetic field that alters the viscosity of the magnetorheological fluid, the torque bias ratio can be dynamically adjusted in real-time without any physical modification to the differential structure. This enables integration with active traction enhancement and electronic stability control programming, allowing the system to adapt to varying traction conditions and control requirements.
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 solution enables efficient, instantaneous torque biasing with minimal wear and size, enhancing compatibility with electronic stability systems by dynamically adjusting viscosity and torque distribution based on traction events, thus improving traction and stability control.
Implementation Method 1
An active torque biasing differential utilizing a housing with an outer and inner annulus, where vanes with orifices are slidably contacting and an electromagnetic coil applies a magnetic field to a chamber containing magnetorheological fluid, allowing dynamic viscosity adjustment and torque biasing
Data Source
AI summary
An active torque biasing differential includes a housing and an outer annulus disposed within the housing. An inner annulus is contained within the outer annulus. The inner annulus includes a plurality of slots. A plurality of vanes are disposed in the slots in the inner annulus. The vanes slidably contact the outer annulus. The vanes include a plurality of orifices formed therein. An electromagnetic coil is placed to apply a magnetic field to a chamber bounded by the outer annulus and inner annulus.