Scroll Compressor Radius Compensation for Tolerance-Induced Torque
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Solution Overview
Problem
Existing scroll compressors in vehicle air conditioning systems face issues with manufacturing tolerances leading to eccentric raceway deviations, which cause torque generation and radial displacement, affecting the durability and efficiency of the scroll components.
Innovation Solution
A scroll compressor design with a larger diameter shaft pin and a radius compensation system, where the pin center is positioned closer to the drive shaft center, reducing torque and bending moments, and eliminating the need for specialized bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional shaft pin design is used, then the structure is simpler, but torque generation and radial displacement occur due to manufacturing tolerances, reducing durability and efficiency
Solution Approach 1:
The patent applies parameter changes by increasing the shaft pin diameter from conventional sizes to 10mm or larger. This dimensional parameter change directly addresses the technical contradiction by providing sufficient structural strength to withstand torque generation from manufacturing tolerances while maintaining reliability of the scroll components.
Solution Approach 2:
The patent introduces asymmetry through the radius compensation system where the shaft pin is positioned eccentrically relative to the drive shaft center. This asymmetric positioning creates a moment arm that compensates for radial displacement caused by manufacturing tolerances, allowing the shaft pin to maintain proper alignment and reduce harmful torques despite dimensional variations in the scroll contours.
2Manufacturing precision
If manufacturing tolerances are tightened to reduce eccentric raceway deviations, then radial fit consistency improves, but manufacturing costs increase
Solution Approach 1:
The patent implements self-service through the radius compensation system that automatically compensates for manufacturing tolerances during operation. The eccentric positioning of the shaft pin creates a self-adjusting mechanism where the moment arm generated by the offset position naturally compensates for radial displacement, eliminating the need for tight manufacturing tolerances and reducing manufacturing costs while maintaining radial fit consistency.
3Strength
If a larger diameter shaft pin is used, then torque and bending moments are reduced, but the edge distance to the drive shaft center must be minimized, potentially increasing complexity
Solution Approach 1:
The patent applies dimensionality change by transitioning from a concentric shaft pin arrangement to an eccentric positioning arrangement. By positioning the shaft pin offset from the drive shaft center, the solution utilizes the radial dimension to create a moment arm that compensates for manufacturing tolerances. This dimensional approach allows the use of larger diameter shaft pins for increased strength while managing the positioning complexity through a systematic eccentric arrangement.
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
Enhances durability and reduces dynamic imbalance, maintaining a consistent radial fit between scrolls, thereby improving the compressor's operational stability and reducing manufacturing costs.
Implementation Method 1
a radius compensation system in the form of an eccentric (32) that is coupled to the drive shaft (36) by means of a shaft pin (34) arranged eccentrically to the drive shaft (36), and to the second scroll (30) by means of a bearing journal (32b) that is eccentric to the shaft pin (34)
Implementation Method 2
These tangential compression forces must be balanced (especially to maintain operation) by a driving or counterforce. This counterforce acts at the center of the shaft journal. Due to the offset of the centers of the shaft and bearing journal, a torque is generated that causes the swing link to rotate around the shaft journal
Data Source
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AI summary
The invention relates to a scroll machine (2), in particular for refrigerant of a vehicle air-conditioning system, said scroll machine comprising: - a first scroll (28) having a first spiral wall (28a) projecting in an axial direction (A), - a second scroll (30) having a second spiral wall (30a) projecting in an axial direction (A), - a drive (16), - a drive shaft (36) by means of which the drive (16) and the second scroll (30) are coupled in a power-transmitting manner, and - a radius compensation system (32) which is connected between the drive shaft (36) and the second scroll (30) and which has an eccentric (32) which is coupled to the drive shaft (36) by means of a shaft pin (34) positioned eccentrically with respect to the drive shaft (36) and is coupled to the second scroll (30) by means of a bearing journal (32b) that is eccentric with respect to the shaft pin (34), a bearing journal axis (46) being positioned at a greater distance from the drive shaft axis (50) than an axis (48) of the shaft pin (34).