Elevator Belt Yarn Sheath Adhesion Fretting
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Solution Overview
Problem
The existing tension members in elevator systems face limited adhesion and load transfer between steel cords and elastomeric jackets, leading to fretting, wear, and wire breakage, which can increase the cost of pre-treating cords with chemical agents or using adhesives.
Innovation Solution
Incorporating helically wrapped yarn threads made from materials like polyester, nylon, or Kevlar around the steel wires within the tension members to enhance adhesion between the elastomeric jacket and the steel cords, reducing fretting and improving the structural stability of the belt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical bonding agents or adhesives are used to increase adhesion between steel cords and elastomeric jacket, then adhesion is improved, but cord cost increases
Solution Approach 1:
A yarn sheath made of organic material (such as polyester, nylon, or cotton) is introduced as an intermediary layer between the steel wires and the elastomeric jacket. This yarn sheath promotes adhesion between the steel cord and the elastomeric jacket without requiring chemical bonding agents or adhesives on the steel cords themselves, thereby avoiding the cost increase associated with pre-treating the steel cords
Solution Approach 2:
The invention creates a composite structure consisting of steel wires, a yarn sheath made of organic material, and an elastomeric jacket. This multi-material composite approach allows each layer to contribute its specific properties: the steel wires provide strength, the yarn sheath provides adhesion promotion and fretting reduction, and the elastomeric jacket provides protection and retention
2Strength
If steel cords are used in elevator belts, then load bearing capacity is achieved, but fretting and wire breakage occur due to limited adhesion with elastomeric jacket
Solution Approach 1:
The yarn sheath acts as a mediator between the steel wires and the elastomeric jacket, reducing fretting between the steel wires by providing a cushioning layer and improving the load transfer interface. This intermediary layer prevents direct contact and friction between the steel wires and the elastomeric jacket, thereby reducing wire breakage while maintaining load bearing capacity
Solution Approach 2:
The yarn sheath provides beforehand cushioning to the steel wires by absorbing and distributing frictional forces before they can cause damage to the steel wires. This protective layer is in place before any fretting or wear can occur, preventing wire breakage through advance protection
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 yarn threads promote better adhesion and reduce fretting, thereby extending the service life of the tension members and the entire elevator belt by stabilizing the load path and minimizing damage from wire breakage.
Implementation Method 1
The at least one yarn thread is configured to promote adhesion of the elastomeric jacket to the plurality of cords and reduce fretting of the plurality of wires
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A belt (16) for suspending and/or driving an elevator car includes a plurality of cords (24). Each cord (24) includes a plurality of wires and at least one yarn thread (32) disposed at an outer periphery of the plurality of wires. An elastomeric jacket (26) substantially retains the plurality of cords (24). The at least one yarn thread (32) is configured to promote adhesion of the elastomeric jacket (26) to the plurality of cords (24) and reduce fretting of the plurality of wires.