Scroll Compressor Radial Coupling for Central Compression Chambers

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Solution Overview

Problem

Existing scroll compressors face challenges in reducing overturning moment, lowering compression ratio, and increasing volumetric efficiency due to the design of the rotating shaft passing through the orbiting scroll, which leads to leakage and reduced wrap thickness, thereby affecting reliability and efficiency.

Innovation Solution

The scroll compressor design includes a configuration that minimizes the distance between the first action point where centrifugal force acts and the second action point where gas force acts, forming compression chambers centrally, and ensures a higher wrap height at the suction side and lower height at the discharge side to enhance wrap rigidity and reduce leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the rotating shaft passes through the orbiting scroll to reduce the overturning moment, then the distance between action points is reduced, but the compression chamber cannot be formed in the center and leakage occurs

Engineering Contradiction:
Improveoverturning momentVSAvoidcompression ratio
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent introduces a radial dimension offset by positioning the rotating shaft coupling portion radially outward from the center of the orbiting scroll. This dimensional change allows the shaft to be coupled at a location that reduces the overturning moment while still enabling central compression chamber formation through the orbiting motion.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The rotating shaft coupling portion acts as an intermediary element between the rotating shaft and the orbiting scroll. It mediates the force transmission while allowing the orbiting scroll to maintain its central orbiting path, thus resolving the conflict between reducing overturning moment and maintaining compression chamber integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of time

If the discharge port is formed eccentric from the center to shorten the compression cycle, then the compression cycle is reduced, but the compression ratio is lowered and wrap thickness is reduced

Engineering Contradiction:
Improvecompression cycleVSAvoidwrap thickness
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent applies local quality by varying the wrap height along the axial direction, with greater wrap height at the suction side and reduced wrap height at the discharge side. This localized differentiation allows the discharge port to be positioned for optimal compression cycle while maintaining sufficient wrap thickness at critical locations through the stepped configuration.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The wrap is segmented into different height zones along the axial direction, creating a stepped structure. This segmentation allows different portions of the wrap to serve different functions: the higher suction-side wrap provides structural integrity and sealing, while the lower discharge-side wrap accommodates the eccentric discharge port positioning.

Inventive Principle:
Principle #1Segmentation

3Productivity

If the wrap height is uniform throughout, then the structure is simple, but the suction volume is limited and discharge side rigidity is insufficient

Engineering Contradiction:
Improvesuction volumeVSAvoidwrap rigidity
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent implements local quality by creating a stepped wrap structure where the wrap height varies along the axial direction. The suction side features greater wrap height to maximize suction volume and accommodate the orbiting motion, while the discharge side has reduced wrap height to maintain rigidity and reduce mass.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The uniform wrap is segmented into distinct height zones, with a higher suction-side wrap and a lower discharge-side wrap. This segmentation allows each zone to be optimized for its specific function: the suction zone prioritizes volume and flexibility, while the discharge zone prioritizes rigidity and structural support.

Inventive Principle:
Principle #1Segmentation

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 stabilizes the orbiting scroll, reduces friction loss, and enhances volumetric efficiency by ensuring effective communication between compression chambers, thereby increasing compression ratio and reliability.

Implementation Method 1

an orbiting scroll (150) coupled to the rotating shaft (125) to perform an orbiting motion relative to the fixed scroll (140)

Methodology Applied
Scientific EffectOrbiting motion:

Implementation Method 2

as the orbiting scroll is coupled to the rotating shaft, an overturning moment acts on the orbiting scroll due to gas force of a compression chamber. Accordingly, it is advantageous, in terms of reducing the overturning moment, to secure a distance as short as possible between a first action point where centrifugal force (bearing reaction force) acts

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP4273402B1Scroll compressor
Publication Date: 2025.08.13 LG ELECTRONICS INC
  • EP4273402B1 patent drawingFigure 1
  • EP4273402B1 patent drawingFigure 2
  • EP4273402B1 patent drawingFigure 3

AI summary

(125) A scroll compressor is disclosed. The scroll compressor includes a rotating shaft coupling portion (153) axially extending from a central portion of an orbiting end plate (151) to radially overlap an orbiting wrap (152), such that an eccentric portion (1251) of a rotating shaft (125) is coupled thereto, and a portion of the orbiting wrap may extend from an end surface of the rotating shaft coupling portion (153) facing a fixed end plate (141). With the configuration, a distance between bearing reaction force and gas reaction force acting on the orbiting scroll can be reduced, to stabilize a behavior of the orbiting scroll and thus reduce back pressure, thereby decreasing friction loss between scrolls. Simultaneously, compression chambers can be formed even in a central portion of the orbiting scroll (150), which can increase a compression ratio and improve volumetric efficiency.