Scroll Compressor Tip Seal with Biasing Member for Leakage Control
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Solution Overview
Problem
Stepped scroll compressors experience significant fluid leakage and reduced strength due to stress concentration at step portions, and the introduction of continuously inclined portions complicates seal performance as tip clearance changes with orbiting angle.
Innovation Solution
A scroll fluid machine design featuring a biasing member, such as a leaf spring or protrusion portions, that maintains contact between the tip seal and tooth bottom across varying tip clearances, ensuring effective sealing despite changes in orbiting angle, with the biasing member deforming to match the tip clearance change and preventing seal displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If step portions are provided on spiral walls to increase compressor capacity, then displacement increases and compressor capacity improves, but fluid leakage in the step portion increases and stress concentrates reducing strength
Solution Approach 1:
The compression process is segmented into two dimensions: circumferential compression by the spiral walls and height direction compression by the step portions. This segmentation allows the compressor to achieve three-dimensional compression, increasing displacement and compressor capacity while managing fluid leakage through the groove structure at the step portions
Solution Approach 2:
The step portions are constructed with composite functionality: the groove portions provide fluid leakage control pathways, while the step structures themselves provide the height direction compression. This composite approach addresses both the capacity increase need and the leakage/strength concerns
2Reliability
If a continuously inclined portion is provided on the wall and end plate, then fluid leakage is reduced and strength is improved, but tip clearance changes for each orbiting angle causing seal performance to decrease
Solution Approach 1:
The tip seal is designed with dynamic adaptability through the groove portion structure that accommodates varying tip clearances. The groove allows the seal to adjust its position dynamically as the tip clearance changes with orbiting angle, maintaining contact with the tooth bottom and preserving seal performance throughout the compression cycle
Solution Approach 2:
The continuously inclined portion changes the geometric parameters of the wall and end plate interface, creating a gradual transition that reduces fluid leakage pathways and distributes stress more evenly. This parameter change from stepped to inclined geometry improves reliability while the groove compensation maintains seal performance
3Productivity
If tip clearance changes for each orbiting angle, then the continuously inclined portion cannot maintain constant seal contact, but fluid leakage increases
Solution Approach 1:
The groove portion acts as an intermediary element between the tip seal and the continuously inclined surface. It mediates the varying tip clearance by providing a recess that allows the seal to maintain contact with the tooth bottom despite the changing geometry, preventing fluid leakage while accommodating the orbital motion
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 effectively reduces fluid leakage and enhances seal performance by ensuring consistent contact between the tip seal and tooth bottom, improving the overall performance of the scroll fluid machine by maintaining seal functionality across the entire orbiting angle.
Implementation Method 1
a biasing member which biases the tip seal toward the tooth bottom side is provided between the tip seal and the groove bottom of the groove portion
Implementation Method 2
the tip seal comes into contact with a tooth bottom facing the tooth tip while sliding on the tooth bottom, and thus, a fluid leakage is suppressed
Implementation Method 3
an inter-facing surface distance between the first end plate and the second end plate facing each other continuously decreases with a constant inclination in the spiral directions
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
Provided is a scroll fluid machine that is capable of improving performance of the scroll fluid machine by effectively exhibiting a tip seal function even when a continuous slope is provided to a wall body and an end plate. A slope in which the distance between opposing surfaces of opposing end plates (3a, 5a) reduces from the outer peripheral side toward the inner peripheral side is provided, and a tip seal (7) that comes into contact with an opposing tooth bottom so as to seal a fluid is provided to a tip seal groove (3d) formed at a tooth tip of the wall body (3b, 5b) corresponding to the slope. A plate spring (11) that urges the tip seal (7) to the tooth bottom side is provided between the tip seal (7) and the groove bottom (3d1) of the tip seal groove (3d).