Scroll Compressor Tip Seal Aspect Ratio
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Solution Overview
Problem
Prior art scroll compressors face issues with tip seal dust generation, wear, and leakage due to the stiffness of traditional tip seals, which require regular replacement and have inefficient sealing mechanisms.
Innovation Solution
The design incorporates tip seals with an aspect ratio of axial length to radial width of 1.25:1 or greater, featuring a first spiral portion at the radially inner side, a second spiral portion at the radially outer side, and an intermediate portion bridging the gap, allowing for increased flexibility and reduced leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional tip seals with 1:1 aspect ratio are used, then the seal structure is simple and stiff, but the seal generates dust, requires long bedding-in time, and has high leakage
Solution Approach 1:
The patent changes the aspect ratio parameter of the tip seal from 1:1 to greater than 1:1, making the axial length greater than the radial width. This parameter change transforms the seal from a stiff structure to a more flexible one that can conform better to the opposing surface, reducing dust generation and improving sealing performance while reducing bedding-in time.
2Reliability
If tip seals with aspect ratio greater than 1:1 are used, then dust generation is reduced and bedding-in time is shortened, but the seal requires radial clearance and more complex positioning
Solution Approach 1:
The groove structure is designed to automatically position the tip seal during operation. The seal's flexible nature allows it to be guided into the groove by the fluid pressure and mechanical contact, eliminating the need for complex external positioning mechanisms. The groove geometry itself provides the positioning function.
3Reliability
If stiff tip seals are used, then the seal maintains its position, but leakage increases due to slow position change and formation of leakage paths
Solution Approach 1:
The patent transforms the tip seal from a static, stiff component to a dynamic, flexible one. The flexible seal can change its position and conformation in response to fluid pressure and orbital motion, continuously adapting to maintain optimal sealing contact. This dynamic capability prevents the formation of persistent leakage paths that occur with stiff seals.
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 configuration results in shorter bedding-in times, reduced dust generation, lower leakage, and increased pumping capability, while also minimizing material usage and costs due to a smaller seal size, leading to a more efficient and cost-effective scroll compressor.
Implementation Method 1
there is a small axial gap between an axial end of the tip seal and the base of the channel so that in use fluid occupying the gap forces the tip seal axially towards the base plate of the orbiting scroll
Data Source
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Figure 7
AI summary
The present invention relates to a scroll compressor (10) which comprises: an orbiting scroll (20) having an orbiting scroll wall (35) extending axially from an orbiting scroll plate (37) towards a fixed scroll; a fixed scroll (22) having a fixed scroll wall (28) extending axially from a fixed scroll plate (30) towards the orbiting scroll; and an axially extending drive shaft (14) having an eccentric shaft portion (16) so that rotation of the eccentric shaft portion imparts an orbiting motion to the orbiting scroll relative to the fixed scroll. An axial end portion (35) of the orbiting scroll wall has a first seal 58 for sealing between the orbiting scroll wall and the fixed scroll plate, and an axial end portion (29) of the fixed scroll wall has a second seal (58) for sealing between the fixed scroll wall and the orbiting scroll plate; and the first seal or the second seal has an aspect ratio of axial length to radial width which is 1 : 1.25 or greater.