Shared MR Fluid Clutch Layout for Lower Dissipation Torque Transfer
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Solution Overview
Problem
State-of-the-art distributed power devices face limitations in dynamic response and efficiency due to hydraulic actuation, which is prone to leakage and maintenance issues, while electromagnetic actuation systems are heavy and suffer from high output inertia, friction, and backlash. Additionally, magnetorheological (MR) fluid properties change over time due to energy dissipation during torque transmission, affecting performance.
Innovation Solution
A system comprising at least two magnetorheological fluid clutch apparatuses with shared MR fluid chambers, allowing controlled slippage and magnetic field actuation to manage MR fluid circulation, reducing energy dissipation and property changes through a common pool of MR fluid and integrated pumping features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple MR fluid clutch apparatuses use separate MR fluid chambers, then each clutch can operate independently, but the system becomes more complex and requires more MR fluid
Solution Approach 1:
The patent combines multiple MR fluid clutch apparatuses into a single integrated unit where multiple clutch assemblies share a common MR fluid chamber. This merging approach reduces the number of separate MR fluid reservoirs and simplifies the overall system architecture while maintaining the functional independence of each clutch through individual coil actuators that can be controlled separately.
Solution Approach 2:
The common MR fluid chamber serves multiple functions simultaneously: it provides the working fluid for all clutch assemblies, acts as a thermal management system through fluid circulation, and enables inter-clutch interaction through shared fluid dynamics. This multi-functional design reduces component count and system complexity.
2Power
If MR fluid is subjected to continuous shear stress during torque transmission, then torque can be transmitted effectively, but the MR fluid properties change over time due to energy dissipation
Solution Approach 1:
The patent implements periodic reversal of the magnetic field applied to the MR fluid, causing the fluid to alternate between sheared and non-sheared states. This periodic action allows the MR fluid to recover its original properties between torque transmission cycles, preventing cumulative property degradation while maintaining effective torque transmission during active phases.
Solution Approach 2:
The system dynamically adjusts magnetic field parameters (strength, duration, reversal frequency) to optimize the balance between torque transmission and fluid property preservation. By controlling the magnetic flux density and exposure time, the patent maintains MR fluid performance characteristics over extended operation periods.
3Reliability
If hydraulic actuation is used for distributed power devices, then reliable mechanical jam resistance is achieved, but dynamic response and efficiency are fundamentally limited
Solution Approach 1:
The patent replaces traditional hydraulic actuation systems with magnetorheological fluid-based magnetic actuation. This substitution eliminates hydraulic fluid leakage issues and mechanical jamming problems while achieving superior dynamic response characteristics through electromagnetic field control, which can be modulated rapidly without the inertia and compliance limitations of hydraulic systems.
4Weight of moving object
If electromagnetic actuators are coupled to reduction gearboxes to reduce weight, then device weight is reduced, but high output inertia, friction and backlash diminish dynamic performance
Solution Approach 1:
The patent extracts and eliminates the reduction gearbox component from the electromechanical actuator system by using direct-drive magnetic actuation with MR fluid clutches. This extraction removes the source of inertia, friction, and backlash problems while achieving weight reduction goals, as the MR fluid clutch apparatus can provide the necessary torque multiplication without mechanical gear trains.
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 enhances the dynamic performance of electromechanical actuation systems by reducing energy dissipation, prolonging MR fluid life, and achieving a compact, lightweight design with uniform temperature distribution, thereby addressing the limitations of existing technologies.
Implementation Method 1
magnetorheological (MR) fluid configured to generate a variable amount of torque transmission between the rotors when subjected to a magnetic field
Implementation Method 2
at least one coil actuatable to deliver a magnetic field through the MR fluid
Implementation Method 3
the MR fluid absorbs energy that may be proportional to the speed difference and the torque transmitted from the input to the output
Data Source
AI summary
A system comprises magnetorheological fluid clutch apparatuses, each magnetorheological fluid clutch apparatus including a first rotor having at least one first shear surface, a second rotor rotating about a common axis with the first rotor, the second rotor having at least one second shear surface opposite the at least one first shear surface, the shear surfaces separated by at least one annular space, magnetorheological (MR) fluid in an MR fluid chamber including the at least one annular space, the MR fluid configured to generate a variable amount of torque transmission between the rotors when subjected to a magnetic field, and coil(s) actuatable to deliver a magnetic field through the MR fluid such that each said magnetorheological fluid clutch apparatus is actuatable to selectively transmit actuation by controlled slippage of the rotors with respect to one another. The MR fluid chambers of the second magnetorheological fluid clutch apparatuses are in fluid communication for the MR fluid to circulate between the magnetorheological fluid clutch apparatuses.