Scroll Compressor Non-Uniform Gap Design
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Solution Overview
Problem
In scroll compressors with a fixed and orbiting scroll, the temperature inside the compression chamber rises exponentially from the outer peripheral side to the inner peripheral side, leading to potential contact between the fixed and orbiting scrolls, especially under high-load conditions, which can result in over-compression of refrigerant.
Innovation Solution
The scroll compressor design features a first and second gap between the wraps and bases that change in a specific manner, with a greater rate of change from the center to an intermediate point compared to the intermediate point to the outer peripheral end, preventing contact by making the gaps locally larger at the center portion, where temperatures are highest, and allowing for easy processing through stepwise formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If steps are formed in the tooth bottom portions to become deeper from outer peripheral side to inner peripheral side, then contact between fixed and orbiting scrolls is prevented, but the steps are insufficient due to exponential temperature rise and contact still occurs under high-load conditions
Solution Approach 1:
The patent applies local quality by creating different gap depths at different radial positions. Specifically, the first gap (between fixed wrap distal end and orbiting base) and second gap (between orbiting wrap distal end and fixed base) are designed with non-uniform distributions where the gap depth varies radially. This local variation ensures adequate clearance at high-temperature inner regions while maintaining compression efficiency at outer regions.
Solution Approach 2:
The patent changes the geometric parameters of the gaps systematically. The first and second gaps are designed with specific rate of change characteristics: the rate of gap increase from center to intermediate point is greater than the rate from intermediate point to outer peripheral end. This parameter optimization prevents contact under various operating conditions while maintaining manufacturing feasibility.
2Productivity
If high compression efficiency is required in low-load condition with smaller wrap volumes, then over-compression occurs in high-load condition leading to excessive temperature rise and increased contact risk
Solution Approach 1:
The patent applies preliminary anti-action by pre-designing the non-uniform gap structure anticipating future thermal expansion and temperature rise. The first and second gaps are configured with specific rate of change characteristics before operation begins, creating built-in clearance that prevents contact even when temperature rises exponentially during high-load operation. This proactive design compensates for the temperature increase that will occur during high-load conditions.
3Ease of manufacture
If uniform gap is maintained between wraps and bases, then manufacturing is simplified, but contact occurs at center portion where temperature rises exponentially
Solution Approach 1:
The patent implements local quality by making the gap depth position-dependent. The first gap and second gap are not uniform but vary radially with specific rate of change characteristics. The gap depth increases from center to outer periphery, with the rate of increase being greater in the center-to-intermediate region than in the intermediate-to-outer region. This local differentiation ensures contact prevention at the high-temperature center portion while remaining manufacturable through stepwise formation.
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 design effectively inhibits contact between the fixed and orbiting scrolls at the center portion of the compression chamber, even under high-temperature conditions, ensuring efficient compression and preventing over-compression of refrigerant, while simplifying the processing of gap formation.
Implementation Method 1
the temperature inside the compression chamber during operation rises more exponentially than rises linearly heading from the outer peripheral side to the inner peripheral side... the first gap from the center of the first wrap to an intermediate point of the first wrap becomes locally larger. Consequently, contact between the distal end of the first wrap and the second base can be inhibited
Data Source
AI summary
A scroll compressor includes fixed and orbiting scrolls, and satisfies at least one of a first condition and a second condition. In the first condition, a first gap between a distal end of the first wrap and the second base changes heading from an outer peripheral side of the first wrap to an inner peripheral side. In the second condition, a second gap between a distal end of the second wrap and the first base changes heading from an outer peripheral side of the second wrap to an inner peripheral side. A rate of change in the first gap in one area is greater than a rate of change in the first gap in another area. A rate of change in the second gap in one area is greater than a rate of change in the second gap in another area.