Scroll Compressor Sliding Bearing With Spherical Graphite Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bearing used in scroll compressors face issues with poor lubrication, high-speed high-load conditions, and difficulty in reducing noise and vibration, with conventional roll bearings requiring high accuracy and increased costs, and sliding bearings lacking seizure and abrasion resistance.
Innovation Solution
A scroll compressor with sliding bearings featuring a graphite-based resin layer on a back metal, where graphite particles have a high degree of graphitization and spherical shape, dispersed in polyimide or polyamide-imide resin, providing improved seizure and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If roll bearings are used in scroll compressors, then reliability and seizure resistance are improved, but device complexity and cost increase
Solution Approach 1:
The patent applies composite materials by creating a sliding bearing layer composed of resin matrix combined with graphite particles and PTFE particles. This composite structure provides both the reliability of seizure resistance (through graphite's lubrication properties) and the simplicity of a sliding bearing design, eliminating the need for complex roll bearing mechanisms while maintaining dependable operation under high-load conditions
Solution Approach 2:
The patent changes the material parameters of the bearing surface by controlling the content ratios of graphite (5-60 wt%) and PTFE (5-40 wt%) particles within the resin layer. By optimizing these compositional parameters, the bearing achieves adequate seizure resistance comparable to roll bearings while maintaining the structural simplicity and cost-effectiveness of sliding bearings
2Ease of manufacture
If sliding bearings with conventional graphite are used, then cost is reduced, but wear resistance and seizure resistance are insufficient
Solution Approach 1:
The patent combines graphite particles with PTFE particles in a resin matrix to create a composite sliding layer. This composite approach leverages the low friction properties of PTFE alongside the lubrication characteristics of graphite, achieving adequate wear and seizure resistance at lower cost compared to roll bearings, while the resin matrix provides structural integrity and ease of manufacturing
Solution Approach 2:
The patent optimizes the particle size parameters of graphite (0.1-10 μm) and PTFE (0.1-10 μm) to enhance wear resistance while maintaining cost-effectiveness. The controlled particle size distribution ensures proper dispersion and packing density, improving the durability of the sliding bearing without requiring expensive manufacturing processes
3Reliability
If flake-shaped graphite is used in sliding bearings, then lubrication is improved, but noise and vibration increase
Solution Approach 1:
The patent employs spherical or near-spherical graphite particles instead of conventional flake-shaped graphite. This spheroidality modification reduces noise and vibration by eliminating the directional orientation and edge-to-edge contact characteristic of flake graphite, while the spherical particles maintain effective lubrication through rolling contact and uniform distribution within the resin matrix
Solution Approach 2:
The patent changes the shape parameter of graphite particles from flake-shaped to spherical, with a sphericity ratio of 0.5 or more. This geometric parameter change reduces the anisotropic friction and vibration associated with flake orientation, thereby lowering noise levels while preserving the lubrication benefits of graphite's layered crystal structure
4Duration of action of stationary object
If high-precision roll bearings are used, then durability is improved, but manufacturing cost increases
Solution Approach 1:
The patent creates a composite sliding bearing layer with resin, graphite particles, and PTFE particles that provides adequate durability for compressor operation. This composite structure achieves acceptable bearing lifetime through the synergistic effects of the materials without requiring the high-precision manufacturing and assembly processes needed for roll bearings, thereby reducing manufacturing costs while maintaining operational longevity
Solution Approach 2:
The patent adopts a sliding bearing design that is inherently simpler and cheaper to manufacture than roll bearings, accepting that it may have a slightly shorter service life but providing adequate durability for the application. The simplified structure eliminates complex precision machining requirements, making the bearing more cost-effective while still meeting the durability needs of scroll compressor operation
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 solution enhances wear resistance, seizure resistance, and quietness, while reducing the size and weight of the compressor, and is cost-effective by using a sliding bearing instead of a roll bearing.
Implementation Method 1
a sliding layer in which graphite having a high degree of graphitization and a unique shape is dispersed in a resin
Data Source
Figure 1
Figure 2
Figure 3
AI summary
[Problem] To exchange the roller bearing that has been used in a scroll compressor mounted in an automobile with a m slide bearing. To provide a slide bearing having a performance that is at least equivalent to that of a roller bearing. [Solution] The slide bearing results from baking onto a back metal a sliding layer of 5-60 wt% graphite having an average diameter of 5-50 µm and a graphitization degree of at least 0.6, the remainder comprising a polyimide resin and/or a polyamide-imide resin. The form of the graphite has: (a) an average shape factor (YAVE) as defined of 1-4 for the particles excluding the minute particles that are no greater than 0.5 times the average diameter, and there being at least 70% by number of particles having a shape factor (Y) in the range of 1-1.5; or (b) graphite particles having a particle ratio of at least 0.5 being at least 50% of the total by number.