Scroll Fluid Machine End Plate Arc Shape for Leakage Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Stepped scroll compressors experience significant fluid leakage and stress concentration at step portions, leading to decreased performance due to increased back clearance between the tip seal groove and the tip seal.
Innovation Solution
A scroll fluid machine design featuring inclined portions on the scroll members where the inter-facing surface distance decreases from the outer to the inner peripheral sides, with end plate inclined portions deeper than the side portions, reducing back clearance and fluid loss by adjusting the tip seal protrusion amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a continuously inclined portion is provided instead of step portions, then stress concentration is reduced and strength is improved, but back clearance increases causing performance decrease
Solution Approach 1:
The end plate is designed with different local geometries: an inclined portion corresponding to the wall inclined portion and a flat portion at the outer peripheral side. This local differentiation allows the central region to have deeper inclination (reducing back clearance) while maintaining structural integrity, and the peripheral region to provide support and stress distribution.
Solution Approach 2:
The solution transitions from a two-dimensional flat end plate to a three-dimensional shaped end plate with varying inclination angles and depths. The end plate inclined portion creates a depth dimension that allows the tip seal to maintain contact across the inclined surface, effectively reducing back clearance in the inclined region while preserving strength through the overall three-dimensional structure.
2Reliability
If the central portion of the end plate inclined portion is made deeper, then back clearance is reduced, but manufacturing complexity increases
Solution Approach 1:
The end plate inclined portion features an arc-shaped cross-section with the central portion being deeper than the side portions. This curved geometry, while providing effective back clearance reduction, can be manufactured using standard machining operations such as end mill cutting, balancing performance requirements with manufacturing feasibility.
Data Source
AI summary
In this scroll fluid machine, a tip seal (7) that is in contact with facing end plates (5a) and that is for sealing in a fluid is provided to a tip seal groove (3d) formed on the tooth tip of a wall (3b). The tooth bottoms of the end plates (5a) have a shape in which a central section is deeper than a side section (5d3) in a width direction orthogonal to the spiral direction of a wall (5b). During operation, the protrusion amount (δ) when the tip seal (7) protrudes from the tooth tip of the wall (3b) in an inclined section and is in contact with the facing end plates is greater than the protrusion amount (δ) when the tip seal (7) protrudes from the tooth tip of the wall (3b) in a flat section and is in contact with the facing end plates.