Multi-Piece Scroll Compressor Crankshaft to Reduce Machining Waste
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Solution Overview
Problem
The manufacturing of single-piece crankshafts for scroll compressors is time-consuming and material-wasteful, with potential inaccuracies due to the need for machining to accommodate varying diameters and offsets, making assembly complex and costly.
Innovation Solution
A crankshaft assembly comprising a separately manufactured crankpin and crankshaft body, aligned and secured with fasteners, allowing for easier assembly and reduced material consumption, with the option to harden the components via laser hardening for enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single-piece crankshaft is manufactured using traditional machining methods, then the structural integrity and strength are maintained, but the manufacturing time and material consumption increase significantly
Solution Approach 1:
The crankshaft is divided into two separate pieces: a crankshaft body and a crankpin. These components are manufactured independently through drawing or turning processes followed by ground and polished (DGP) treatment, then assembled together using a fastener. This segmentation allows each component to be produced more efficiently while maintaining the overall structural integrity of the crankshaft assembly.
2Adaptability or versatility
If a single-piece crankshaft is machined to accommodate varying diameters and offsets, then the design flexibility is achieved, but the manufacturing complexity and cost increase
Solution Approach 1:
By separating the crankshaft into a body and crankpin components, each can be manufactured using standard drawing or turning processes with DGP treatment. The adaptability for varying diameters and offsets is achieved through the modular assembly approach rather than complex single-piece machining, thereby reducing manufacturing complexity while maintaining design flexibility.
Solution Approach 2:
Different sections of the crankshaft (body and crankpin) can have different material properties and surface treatments optimized for their specific functional requirements. The crankpin, which experiences high contact stresses, can be separately treated and assembled with the crankshaft body, allowing localized optimization without complicating the entire manufacturing process.
3Strength
If traditional machining methods are used for single-piece crankshafts, then the structural strength is maintained, but the material consumption increases
Solution Approach 1:
The crankshaft is segmented into crankshaft body and crankpin components that can be manufactured using efficient drawing or turning processes. This approach minimizes material waste compared to traditional single-piece machining, as each component can be produced close to its final shape with minimal material removal. The DGP treatment ensures adequate strength while using less material.
4Productivity
If a multi-piece crankshaft assembly is used, then the assembly efficiency and production speed increase, but the number of components and assembly steps increase
Solution Approach 1:
The crankshaft is divided into two main components (crankshaft body and crankpin) that can be manufactured simultaneously through drawing or turning processes with DGP treatment, then quickly assembled using a simple fastener. This segmentation enables parallel manufacturing of components, increasing production speed while keeping the number of additional components minimal (only one fastener is added).
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 multi-piece crankshaft assembly reduces manufacturing time and material waste, enhances accuracy, and simplifies assembly, while the hardening process improves durability and reduces distortion, leading to a more efficient and cost-effective production process.
Implementation Method 1
the hardening is accomplished via a laser hardening process
Data Source
AI summary
A crankshaft assembly for a scroll compressor is disclosed. The crankshaft assembly includes a crankpin having a plurality of apertures therethrough. A crankshaft body has an aperture therethrough. The aperture of the crankshaft and one of the plurality of apertures of the crankpin being aligned when in an assembled state such that in operation fluid flows between the aperture of the crankshaft body and the one of the plurality of apertures of the crankpin. The crankshaft body includes a second aperture aligned with a second of the plurality of apertures of the crankpin. The crankpin and the crankshaft body are separate members. A fastener extends through the second of the plurality of apertures of the crankpin and into the second aperture of the crankshaft body to secure the crankpin and the crankshaft body together in the assembled state.