Cold Forged Scroll Compressor Crankshaft with Reinforced Shaft
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Solution Overview
Problem
Conventional scroll compressors face challenges in manufacturing an inexpensive unit with a crankshaft made by cold forging, as it reduces the eccentric amount, affecting the variable circling radius mechanism's performance and reliability, and using a needle bearing increases the risk of crankshaft damage due to deflection.
Innovation Solution
A scroll fluid machine design featuring a crankshaft with a reinforced shaft unit and an eccentricity ratio of 1≦f≦2, manufactured by cold forging, and supported by a needle bearing to maintain the variable circling radius mechanism's functionality and prevent crankshaft deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the crankshaft is manufactured by cold forging to reduce manufacturing cost, then the manufacturing cost decreases, but the eccentric amount between the rotating shaft and eccentric shaft is reduced, affecting the variable circling radius mechanism's performance
Solution Approach 1:
The patent optimizes the eccentricity ratio parameter to a specific range (1≦f≦2) to compensate for the reduced eccentric amount caused by cold forging. This parameter change ensures that the variable circling radius mechanism maintains sufficient performance while using the cost-effective cold forging manufacturing process
Solution Approach 2:
The patent introduces a reinforced shaft unit with larger diameter at the driving device side of the circular column-like large diameter unit. This local reinforcement compensates for the reduced eccentric amount by providing additional structural integrity, ensuring the crankshaft can maintain the required eccentricity for proper mechanism operation
2Ease of manufacture
If a needle bearing is used to support the circular column-like large diameter unit to reduce cost, then the manufacturing cost decreases, but the crankshaft may deflect and come into partial contact with the needle bearing, reducing reliability
Solution Approach 1:
The reinforced shaft unit with larger diameter is specifically positioned at the driving device side where the needle bearing supports the circular column-like large diameter unit. This local reinforcement prevents crankshaft deflection in the critical area, avoiding partial contact with the needle bearing and maintaining reliability while using the cost-effective needle bearing
3Reliability
If the eccentric amount is increased to improve the variable circling radius mechanism performance, then the mechanism performance improves, but the manufacturing cost increases due to the need for hot forging instead of cold forging
Solution Approach 1:
By optimizing the eccentricity ratio to 1≦f≦2, the patent achieves sufficient variable circling radius mechanism performance without requiring the high eccentric amounts that would necessitate expensive hot forging. This parameter optimization allows cold forging to be used while maintaining mechanism performance
Solution Approach 2:
The reinforced shaft unit provides partial reinforcement only where needed (at the driving device side) rather than reinforcing the entire crankshaft. This selective reinforcement achieves the necessary structural integrity for proper mechanism operation while minimizing additional manufacturing complexity and cost
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 design allows for a cost-effective scroll fluid machine with improved reliability and performance of the variable circling radius mechanism, reducing manufacturing costs and preventing needle bearing damage.
Implementation Method 1
the circular column-like large diameter unit of the crankshaft is rotatably coupled to the housing via a needle bearing
Implementation Method 2
produced by a step-by-step cold forging process
Implementation Method 3
a material is produced by a step-by-step cold forging process
Implementation Method 4
the predetermined diameter of the reinforced shaft unit is set so that a deflection amount towards a side of the eccentric shaft falls within an acceptable range
Data Source
AI summary
Provided is a scroll fluid machine that, by using a crankshaft manufactured by cold forging and a needle bearing, can sufficiently exhibit the performance of a variable circling radius mechanism, can provide a sufficient reliability on a bearing portion of the crankshaft, and can be manufactured inexpensively. For this purpose, in a crankshaft 60 used for a driving force transmission system, a reinforced shaft unit 63 and a circular column-like large diameter unit 61 are formed at an end of a rotating shaft 16, a material is produced by a cold forging process so that an eccentric shaft 62 projects from the circular column-like large diameter unit 61, the circular column-like large diameter unit 61 is rotatably coupled to a housing 11 via a needle bearing 64, and the variable circling radius mechanism is stably operated with rigidity increased by the reinforced shaft unit 63.