Pre-Stretched Disc Coupling Assembly for Misalignment and Low Runout
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Solution Overview
Problem
Existing mechanical couplings face challenges in accommodating misalignment and maintaining torque transmission efficiency, while also being difficult to assemble due to pre-stretch requirements and tight tolerances.
Innovation Solution
The coupling assembly incorporates disc packs with bushings that have internal threads and axial extensions, allowing for increased pre-stretch and easier assembly by aligning bolt holes and using threadless locating pockets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If disc packs are introduced to allow misalignment, then adaptability is improved, but device complexity worsens
Solution Approach 1:
The coupling assembly is divided into modular components: drive interface, driven interface, and one or more disc packs positioned between them. Each disc pack consists of multiple disc elements that can independently flex to accommodate misalignment. This segmentation allows the adaptability function to be isolated to specific components while keeping the overall structure manageable.
Solution Approach 2:
The disc pack incorporates flexible disc elements that can dynamically adjust their position and orientation to accommodate misalignment between drive and driven components. The disc elements are designed with controlled flexibility to bend and rotate, providing adaptive misalignment compensation while maintaining torque transmission.
2Reliability
If pre-stretch is applied to eliminate buckling, then reliability is improved, but ease of manufacture worsens
Solution Approach 1:
The disc pack is pre-stretched during manufacturing to put the disc elements under initial tension, which eliminates buckling during operation. This preliminary action of pre-stretching is performed in a controlled manufacturing environment using specialized equipment, allowing the complex pre-stretching process to be automated and standardized, thereby improving ease of manufacture despite the inherent complexity.
Solution Approach 2:
The disc elements are designed with specific geometric parameters and material properties that enable them to be pre-stretched to a predetermined level. By optimizing parameters such as disc thickness, diameter, and material modulus, the pre-stretch process can be controlled within tight tolerances, making manufacturing more predictable and easier to execute.
3Manufacturing precision
If tight tolerances are used to minimize runout, then manufacturing precision is improved, but ease of manufacture worsens
Solution Approach 1:
The disc pack design incorporates self-aligning features that automatically compensate for minor misalignments and tolerances during assembly. The flexible disc elements naturally adjust to center themselves on the rotational axis, reducing the need for tight manufacturing tolerances and making assembly easier while still achieving low runout.
Solution Approach 2:
The disc pack serves multiple functions simultaneously: it transmits torque, accommodates misalignment, and provides self-alignment to minimize runout. This multi-functionality is achieved through the flexible disc elements that can both transmit power and automatically adjust to maintain proper alignment, reducing the need for separate alignment adjustment mechanisms.
4Reliability
If disc packs with smaller bolt circle than mating flanges are used, then pre-stretch is improved, but device complexity worsens
Solution Approach 1:
The disc pack is designed with an asymmetric bolt circle configuration where the bolt circle diameter is intentionally smaller than that of the mating flanges. This asymmetric design creates the necessary pre-stretch condition while the offset between bolt circles is compensated by the flexible disc elements, which can accommodate the dimensional difference through their flexibility.
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
This design enhances torque transmission capacity, reduces runout, and simplifies assembly, while eliminating the need for pilot rings and reducing production costs.
Implementation Method 1
The disc packs flex to allow axial, parallel, and angular misalignment
Implementation Method 2
bushings with internal threads and axial extensions, allowing for increased pre-stretch
Implementation Method 3
An input torque from the power source from the drive end is transferred via the coupling to the driven end
Data Source
AI summary
A disc pack includes stacked disc plates defining a first side and second side of the disc pack. Bolt holes extend through the sides of the disc pack and define a bolt circle. Bushings extend through the bolt holes. Each bushing includes a head at a first end bearing against the first side of the disc pack and a second end that extends axially outside the bolt hole. A washer surrounds at least a portion of the second end and bears against the second side of the disc pack to hold the disc plates together. The disc pack is configured to increase from a first diameter defined by the bolt circle to a second diameter defined by the bolt circle that is at least 0.37% greater than the first diameter when the disc pack is pre-stretched.