Leaf-Spring Dry Multi-Plate Clutch for Low-Friction Axial Movement
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Solution Overview
Problem
Multi-plate clutches in hybrid drivetrains experience high friction losses and manufacturing complexity due to unfavorable positioning and jamming issues, leading to increased costs.
Innovation Solution
A dry multi-plate clutch design featuring outer and inner plates mounted on leaf springs, with the leaf springs integrated into the lining carrier or connected to steel plates, allowing for axial movement without significant friction during clutch opening and closing, and ensuring torque transmission reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If plates are mounted on leaf springs to enable axial movement without friction, then friction losses are reduced, but device complexity increases
Solution Approach 1:
Leaf springs are introduced as intermediary elements between the plates and the clutch housing, serving as both mounting supports and friction-reducing guides that enable axial movement during clutch operation
Solution Approach 2:
Thin leaf spring elements are used to provide flexible mounting for the plates, allowing axial displacement while maintaining structural integrity and reducing friction compared to rigid mounting solutions
2Loss of energy
If leaf spring force is reduced to minimize friction, then axial movement friction is reduced, but torque transmission reliability deteriorates
Solution Approach 1:
The leaf spring stiffness is designed to be dynamic relative to operating conditions - sufficiently compliant during axial movement to reduce friction, yet sufficiently rigid during torque transmission to ensure reliability, achieving optimal performance across different operational phases
Solution Approach 2:
The mechanical properties of leaf springs (stiffness, thickness, material) are optimized to change their effective behavior based on operational phase, providing low friction during axial displacement while maintaining high torque transmission capability when engaged
3Manufacturing precision
If plate positioning relies on toothing with surface contact, then axial positioning is achieved, but unfavorable positioning and jamming occur due to tolerances
Solution Approach 1:
Leaf springs serve as intermediary guiding elements that replace direct surface contact between plates and housing, eliminating the jamming issue caused by tolerance accumulation in traditional toothing arrangements
Solution Approach 2:
The thin leaf spring guides provide precise axial positioning through their geometric constraints while their flexibility accommodates manufacturing tolerances, preventing the binding and jamming that occurs with rigid surface contact positioning
4Manufacturing precision
If complex plate carrier geometry is used to position plates, then plate positioning is improved, but manufacturing costs increase
Solution Approach 1:
The plate carrier is segmented into simpler components with plates mounted on leaf springs rather than a single complex carrier structure, reducing manufacturing complexity while maintaining positioning precision through the distributed leaf spring mounts
Solution Approach 2:
Thin leaf spring elements replace complex rigid carrier geometry, providing necessary positioning and guidance functions through their flexible, geometrically-defined structure rather than through complex solid carrier shapes
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 solution reduces friction losses and manufacturing complexity by enabling axial movement with minimal friction and maintaining torque transmission reliability, thus improving the efficiency and cost-effectiveness of the multi-plate clutch.
Implementation Method 1
these are each mounted on at least three leaf springs or leaf spring packs... the leaf spring can no longer slide in its guide (=friction rubbing). However, the plate can continue to move axially due to the resulting leaf spring deflection
Implementation Method 2
the lining plate has friction plates on at least one side, e.g., on both sides, i.e., friction surfaces which are brought into frictional engagement e.g., with adjacent steel plates
Data Source
AI summary
A multi-plate clutch includes an outer plate mounted on a radial outside and axially displaceable, an inner plate mounted on a radial inside and axially displaceable, and a plurality of leaf springs. The plurality of leaf springs is distributed around an outer circumference of the outer plate to mount the outer plate in a torque-transmitting manner on a rotor pot, or the plurality of leaf springs is distributed in an inner circumference of the inner plate to mount the inner plate in a torque-transmitting manner on a driving ring. In an example embodiment, the multi-plate clutch is a dry multi-plate clutch for a hybrid drivetrain. In an example embodiment, the multi-plate clutch includes a plurality of outer plates and a plurality of inner plates.