Slotted Contact Washer for High-Current Rotating Joints
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Solution Overview
Problem
Existing devices for transferring high electric currents between rotating conductive members face issues with high joint resistance, overheating, and uncontrolled spring force due to current constriction, especially in continuous rotation scenarios.
Innovation Solution
A contact washer with inner and outer slots that divide it into fingers, allowing current to flow in parallel radial paths, reducing heating and repulsive force, and providing a linearly dependent restoring spring force through compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a flat conductive washer is used for high current transfer, then the结构简单 (structure is simple), but the joint resistance is high causing overheating
Solution Approach 1:
The flat conductive washer is divided into multiple flexible fingers by introducing inner slots and outer slots. Each finger acts as an independent current path, increasing the number of contact points between the washer and conductive members. This segmentation distributes the high current across multiple parallel paths, reducing current density at each contact point and thereby reducing resistive heating and joint temperature.
2Device complexity
If a flat conductive washer is used, then the structure is simple, but current constriction causes repulsive force requiring large spring force
Solution Approach 1:
By segmenting the washer into multiple fingers through inner and outer slots, the current is distributed across multiple parallel paths rather than being concentrated at a few discrete points. This reduces current constriction effects and the associated repulsive forces, allowing for more controlled spring force requirements.
Solution Approach 2:
The introduction of slots creates flexible fingers that can dynamically adapt their contact pressure and distribution. As the washer is compressed, the fingers bend and twist, distributing the contact force more evenly across the contact surface. This dynamic behavior reduces peak repulsive forces and allows for more predictable spring force characteristics.
3Force
If the washer is compressed to maintain contact, then contact force is sufficient, but the restoring spring force is difficult to control and changes during use
Solution Approach 1:
The slots transform the rigid washer into a structure with flexible fingers that can dynamically adjust during compression. The fingers bend and twist in a controlled manner, providing a more linear and predictable restoring spring force characteristic throughout the compression range. This improves reliability by maintaining consistent contact force.
4Device complexity
If discrete contact points are used, then the washer structure is simple, but heating at contact points is high
Solution Approach 1:
The washer is segmented into multiple fingers that create numerous discrete contact points distributed across the contact surface. While each individual contact point carries less current, the cumulative effect of many parallel current paths significantly reduces the total resistive heating. This is achieved by introducing inner slots and outer slots that divide the continuous washer into finger-like segments.
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
Significantly reduces heating and repulsive force, maintaining consistent resistance to rotation and preventing jamming, even under high current conditions.
Implementation Method 1
this forces the current flowing through the washer from the central aperture to the peripheral edge flow in a number of parallel radial paths
Implementation Method 2
as the washer is compressed the fingers tend to twist. This produces a restoring spring force which is approximately linearly dependent on the degree of compression of the washer
Implementation Method 3
the contact washer further comprises an electrically conductive coating layer coating the metal plate, the electrical conductivity of the coating layer being higher than that of the metal plate
Data Source
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AI summary
A contact washer comprising a metal plate defined by first and second faces and a peripheral edge, the metal plate having an aperture extending therethrough defined by an aperture edge of the plate; the washer further comprising at least one of- (a) a plurality of inner slots, each inner slot extending through the plate from the first face to the second face and from the aperture edge part way to the peripheral edge; and (b) a plurality of outer slots, each outer slot extending through the plate from the first face to the second face and from the peripheral edge part way to the aperture edge.