Elevator Pulley Intermediate Layer for Shrinkage-Compatible Assembly
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Solution Overview
Problem
Existing pulley manufacturing methods face challenges in processing exotic plastics with high process reliability to achieve desired properties like low friction and damping, particularly due to material incompatibilities and shrinkage issues.
Innovation Solution
Incorporating an intermediate layer made of a second plastic between the main body and the running-surface shell, which is different from the first plastic, allowing for decoupled manufacturing and improved joint stability, thereby compensating for material incompatibilities and shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a running-surface shell made of exotic plastic is used to achieve low friction and damping properties, then the functional properties of the pulley are improved, but the manufacturing reliability deteriorates due to material incompatibility and shrinkage issues
Solution Approach 1:
The pulley is divided into three separate components: a main body, a running-surface shell, and an intermediate layer. This segmentation allows each component to be manufactured independently using materials optimized for their specific functions, with the running-surface shell made from exotic plastic for low friction and damping, while the main body can be made from a different material suitable for structural requirements.
Solution Approach 2:
An intermediate layer made of a second plastic different from the running-surface shell is introduced between the main body and the running-surface shell. This intermediate layer acts as a mediator that compensates for shrinkage differences and creates reliable joints between materials with incompatible physical properties, ensuring manufacturing reliability while allowing the use of exotic plastics for the running surface.
2Ease of manufacture
If the running-surface shell material has significant shrinkage while the main body material does not shrink, then the desired functional properties are achieved, but internal stresses cause cracking and reduce structural integrity
Solution Approach 1:
The intermediate layer made of a second plastic serves as a buffer that absorbs and compensates for the significant shrinkage of the running-surface shell material. This prevents the development of excessive internal stresses that would otherwise cause cracking, while still allowing the running-surface shell to be made from material with the desired functional properties.
Solution Approach 2:
The invention changes the material parameter composition by using a composite structure with three different materials. The intermediate layer's material properties are specifically selected to bridge the gap between the main body material (with minimal shrinkage) and the running-surface shell material (with significant shrinkage), thereby maintaining structural integrity while enabling the use of exotic plastics.
3Device complexity
If the running-surface shell adheres poorly to the main body, then manufacturing simplicity is maintained, but joint strength is insufficient and the assembly fails
Solution Approach 1:
The intermediate layer acts as an adhesive mediator between the running-surface shell and the main body. It is specifically designed to form strong bonds with both materials, creating reliable joints even when the running-surface shell material adheres poorly to the main body material directly. This maintains manufacturing simplicity while ensuring adequate joint strength.
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 ensures reliable production of pulleys with low friction and damping properties by providing a strong, form-fitting or force-fitting joint between the main body and the running-surface shell, even when their physical properties are incompatible.
Implementation Method 1
The joints between the materials can be form-fitting or force-fitting or can be the result of physical and/or chemical bonding (integral).
Implementation Method 2
In order to achieve highly specific properties of the running-surface shell or of the running surface itself, the plastics for the running-surface shell can be specifically selected. For example, particularly low friction or a degree of damping can be achieved in this way.
Data Source
AI summary
A pulley for a suspension element (2) of an elevator, having at least one bearing (3), a main body (4) and a running-surface shell (5) made of a first plastic, where the at least one bearing (3) is retained by the main body (4), wherein, between the main body (4) and the running-surface shell (5), an intermediate layer (6) joined to the main body (4) and to the running-surface shell (5) is provided, and the intermediate layer (6) contains a second plastic different from the first plastic.