Scroll Compressor Boss Rigidity for Bearing Stress
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Solution Overview
Problem
The eccentric shaft portion of a scroll compressor deforms under load, leading to increased bearing stress and potential wear or seizure of the sliding bearing near the distal end and root of the boss portion, which existing solutions like tapered axial end portions of the sliding bearing cannot adequately address.
Innovation Solution
The axially central portion of the boss portion is made more rigid than the connection and distal end portions, and the central portion can be composed of a different material than the connection and distal end portions, with an optional recess on the eccentric shaft portion to reduce bearing stress and prevent wear or seizure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the eccentric shaft portion is used to transmit driving force to the movable scroll, then the scroll compressor can operate, but the eccentric shaft portion deforms under load causing increased bearing stress and potential wear or seizure of the sliding bearing
Solution Approach 1:
The boss portion is designed with non-uniform thickness, having a thicker central portion and thinner connection portions. This local quality variation allows the central portion to bear more load while reducing stress concentration at the connection portions where the sliding bearing is located, thereby preventing bearing wear and seizure while maintaining power transmission capability
Solution Approach 2:
The boss portion is constructed using composite materials with different rigidity characteristics. The central portion uses a more rigid material to support the eccentric shaft, while the connection portions use materials with appropriate flexibility to reduce stress transmission to the sliding bearing, solving the contradiction between power transmission and bearing durability
2Reliability
If the axial central portion of the boss portion is made more rigid than the connection portion, then bearing stress at the connection portion is reduced, but the structural complexity increases
Solution Approach 1:
Instead of making the entire boss portion more rigid, only the central portion is reinforced with thicker walls and/or different material. This localized reinforcement reduces the overall structural complexity while achieving the goal of reducing bearing stress at the connection portions through stress distribution
3Reliability
If tapered axial end portions are used on the sliding bearing, then wear and seizure are reduced, but the bearing cannot adequately support load under large load conditions
Solution Approach 1:
Instead of modifying the sliding bearing geometry (tapered ends), the invention inverts the approach by modifying the boss portion structure. The non-uniform thickness design of the boss portion directly addresses the load support issue while the material composition approach prevents stress concentration, thereby solving both wear prevention and load support capability simultaneously
Data Source
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AI summary
A scroll compressor includes: a scroll compression element (10) including a movable scroll (11); a drive shaft (15) configured to allow the movable scroll (11) to rotate; a boss portion (11b) connected to a back surface of the movable scroll (11), the boss portion (11b) being configured to rotatably support an upper end portion of the drive shaft (15) configured as an eccentric shaft portion (15a); and a sliding bearing (17) provided between the boss portion (11b) and the eccentric shaft portion (15a). An axially central portion (111) of the boss portion (11b) is more rigid than a connection portion (112) of the boss portion (11b) connected to the movable scroll (11) is.