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Spiralock Locking Fasteners Ensure Adequate Clamp Load
日期: 2017-12-11
Battery packs on EV and hybrid vehicles only store the energy of about 1-2 gallons of gasoline. In addition, energy losses can come from the fasteners that hold the battery packs together. Traditional fasteners have difficulty maintaining electrical conductivity and connectivity with EV and hybrid battery terminals.
 
Traditional fasteners typically lose about half of their original clamp load after extended car vibration and thermal cycling. In addition, heat can build up due to the battery’s live current, and electric arcing can occur, which is a potential fire or explosion hazard.
 
Inside EV and hybrid batteries, whether lithium or acid-based, several packs are typically linked to each other in a series. If a connection is weakened by losing clamp load, you lose not just one battery cell but the whole series of battery cells. The Spiralock locking thread may resolve many of these issues, as it can safely harness every milliamp of hybrid vehicle electricity without overheating.
 
The Spiralock locking thread can help ensure adequate clamp load and joint integrity in critical areas from the battery pack and battery terminals to the battery box itself, while improving connectivity and battery life.
 
Traditional locking fasteners, which have a 60° thread form, feature a gap between the crest of the male and female threads that can lead to vibration-induced thread loosening, inadequate clamp load, and overheating in critical EV and hybrid battery joints. Stress concentration and fatigue at the first few engaged threads is also a problem, along with an increased probability of shear, especially in soft metals, due to a tendency toward axial loading. Temperature extremes can also expand or contract surfaces and materials, potentially compromising joint integrity.
 
 
To increase engine power and efficiency, hybrid and electric vehicles’ battery packs are held together by Spiralock fasteners from the inside.
 
The Spiralock locking fasteners overcome these challenges while also eliminating traditional concerns about debris, stripping, or additional stack height. What makes this re-engineered thread form unique is its 30° wedge ramp added at the root of the thread, which mates with standard 60° male thread fasteners.
 
The wedge ramp allows the bolt to spin freely relative to female threads until clamp load is applied. The crests of the standard male thread form are then drawn tightly against the wedge ramp, eliminating radial clearances and creating a continuous spiral line contact along the entire length of the thread engagement. This continuous line contact spreads the clamp force more evenly over all engaged threads, improving resistance to vibrational loosening, axial-torsional loading, joint fatigue, and temperature extremes.
 
The free-spinning design allows a nut to be run all the way down by finger with little resistance between meshing threads, so there is no chipping, debris, or dust, which in turn eliminates the potential for later debris-caused electrical arcing. The increase in retained clamp load and conductivity helps with terminals connecting leads together as well as from individual battery cells to large grounding terminals which pool many leads into one connection, and to any electrical connections carrying high current, high capacity charges throughout EV or hybrid systems.
 
 
 
Source: www.0086jgj.cn