Scroll Compressor Sliding Bearing Step Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional scroll compressors face challenges in reducing manufacture cost while maintaining durability, especially under severe conditions such as intermittent operation and varying rotational speeds, due to excessive load on bearings leading to local abrasion.
Innovation Solution
The implementation of a scroll compressor design featuring cylindrical sliding members with distinct axial lengths forming steps, allowing for relative rotation in multiple boundary zones and effective lubrication, reducing the risk of abrasion and enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If roller bearings are adopted between the drive bush and boss portion, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive roller bearings with sliding bearings that have a simpler structure and lower manufacturing cost. The sliding bearing uses a bush-like structure with lubrication to achieve acceptable reliability at reduced cost, accepting that it may have shorter service life under severe conditions compared to roller bearings.
Solution Approach 2:
The patent substitutes the rolling contact mechanism of roller bearings with a sliding contact mechanism using sliding bearings. This mechanical substitution simplifies the bearing structure, reduces manufacturing complexity, and lowers cost while maintaining functional reliability through proper lubrication design.
2Ease of manufacture
If sliding bearing is adopted to reduce cost, then manufacturing cost decreases, but durability deteriorates under severe conditions
Solution Approach 1:
The sliding bearing is divided into multiple boundary zones (first boundary zone between outer sliding member and boss portion, second boundary zone between outer sliding member and drive bush) to distribute the load. This segmentation prevents excessive load concentration on any single area, reducing local abrasion and improving durability under severe operating conditions.
Solution Approach 2:
The patent applies different functional characteristics to different parts of the sliding bearing. The outer sliding member has specific surface properties and dimensional tolerances optimized for its interaction with both the boss portion and drive bush. The chamfered inner circumferential surface of the drive bush provides localized load distribution at critical areas, enhancing durability where needed most.
3Device complexity
If sliding bearing with single length is used, then structure is simplified, but load distribution is insufficient causing local abrasion
Solution Approach 1:
The sliding bearing employs asymmetric design where the outer sliding member has different axial lengths at its two ends, creating a stepped structure. This asymmetry allows the bearing to accommodate the offset between the drive shaft axis and boss portion axis, distributing loads more evenly across the contact surfaces and preventing localized stress concentration that would cause abrasion.
Solution Approach 2:
The patent addresses the misalignment issue by extending the solution into the axial dimension. Instead of trying to align axes perfectly in the radial plane, the asymmetric axial lengths of the outer sliding member compensate for the axial offset, allowing proper load distribution despite the dimensional mismatch between the drive shaft and boss portion positions.
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 achieves cost reduction and improved durability by distributing loads across multiple boundary zones and ensuring adequate lubrication, effectively preventing local abrasion and maintaining performance under severe conditions.
Implementation Method 1
an outer sliding member and an inner sliding member which form a step at at least one end in an axial direction, hold a lubricating oil and supply the lubricating oil, thereby, relative rotation is easily generated
Data Source
AI summary
In a motor-driven scroll compressor of the present invention, a double-sided sliding bearing is provided a space between a drive bush and a boss portion. The double-sided sliding bearing has a cylindrical outer sliding member that is provided in the boss portion, and a cylindrical inner sliding member that is provided in the bush portion. In an outer boundary zone of an inner circumferential surface of the boss portion and an outer circumferential surface of the outer sliding member, and an inner boundary zone of an inner circumferential surface of the inner sliding member and an outer circumferential surface of the bush portion, relative rotation is generated. The outer sliding member and the inner sliding member have different lengths in an axial direction, and thereby form a first and a second steps at both ends in the axial direction.