Scroll Compressor Bearing Overlap and Differential Pressure Cooling
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Solution Overview
Problem
In scroll compressors, the existing bearing support structures lead to increased frictional losses, noise, and reduced reliability due to eccentric loads and inadequate oil supply to bearings, causing overheating and abrasion.
Innovation Solution
A scroll compressor design featuring a differential pressure space between the first and second bearings, allowing for efficient oil supply and cooling through an oil passage in the rotating shaft, which reduces frictional losses and enhances bearing reliability by forming a recess at the upper end of the rotating shaft to overlap the bearings radially and create a pressure difference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the support point of the rotating shaft is axially spaced apart from the point of application of rotational force, then the rotating shaft can be supported radially, but the bearing load increases due to large eccentric load
Solution Approach 1:
The patent moves the support point from a single axial location to an overlapping radial arrangement, utilizing the radial dimension to reduce the moment arm and thereby reducing the bearing load while maintaining support stability
2Reliability
If the support point is axially spaced apart from the point of application, then radial support is achieved, but frictional loss increases
Solution Approach 1:
By utilizing the radial dimension through overlapping bearing arrangement, the patent reduces the axial distance between support and force application points, thereby reducing frictional losses while maintaining adequate radial support
3Loss of energy
If the boss coupling groove is formed eccentric to reduce eccentric load, then frictional loss and noise are reduced, but oil supply to the bearing becomes inadequate
Solution Approach 1:
The patent segments the bearing support system into two overlapping bearings with distinct functions: the first bearing handles radial support with reduced eccentric load, while the second bearing receives dedicated oil supply through the rotating shaft to ensure adequate lubrication
Solution Approach 2:
The rotating shaft acts as an intermediary, containing an oil passage that directly supplies oil to the second bearing, ensuring adequate lubrication despite the eccentric configuration
4Length of stationary object
If the bearings are positioned close together to reduce size, then the compressor can be reduced in size, but oil cannot smoothly pass through the bearing causing overheating
Solution Approach 1:
The patent creates a localized high-pressure oil supply region at the second bearing through the rotating shaft oil passage, ensuring adequate cooling and lubrication in the specific area where heat generation occurs, while maintaining compact overall dimensions
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 effectively suppresses frictional losses and rapidly cools the bearings, extending their lifespan and improving compressor efficiency and reliability by ensuring smooth oil supply and distribution.
Implementation Method 1
a differential pressure space between the first bearing and the second bearing, so that oil supplied through an oil passage of the rotating shaft can be smoothly distributed to the second bearing by the differential pressure
Implementation Method 2
oil supplied through an oil passage of the rotating shaft can be smoothly distributed to the second bearing
Data Source
AI summary
A scroll compressor includes a first scroll including a fixed wrap, a second scroll comprising an orbiting wrap, and a boss portion, a rotating shaft including an eccentric portion inserted into the boss portion of the second scroll to transfer a rotational force, a frame having a shaft hole, a first bearing provided between the shaft hole of the frame and an outer circumferential surface of the rotating shaft, and a second bearing provided between an inner circumferential surface of the boss portion and an outer circumferential surface of the eccentric portion of the rotating shaft, wherein a differential pressure space portion is formed between the first bearing and the second bearing in a radial direction, and has a radial cross section wider than a radial gap between an inner circumferential surface of the second bearing and the outer circumferential surface of the eccentric portion.