Scroll Compressor Sealing Layout for Oil-Free Brake Air

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Solution Overview

Problem

Existing scroll compressors risk introducing oil into the compression chamber due to the orbiting motion of the displacement spiral, which can lead to oil accumulation in closed gas circuits, posing a critical issue in compressed air brake systems.

Innovation Solution

A scroll compressor design with a sealing element fixed in the displacement spiral base, sealing against a sliding plate, and a wiper element to remove oil residues, combined with a compact two-stage configuration and water cooling, ensuring an oil-tight seal and efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a seal is provided between the displacement spiral and the housing to prevent oil ingress, then oil-free compressed air generation is improved, but friction between the seal and displacement spiral base increases wear of the seal

Engineering Contradiction:
Improveoil-free compressed air generationVSAvoidwear of the seal
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A sliding plate is introduced as an intermediary component between the sealing element and the displacement spiral base. The sliding plate absorbs the friction and wear from the orbiting motion, while the sealing element remains relatively stationary against the sliding plate. This mediator protects the sealing element from direct contact wear, maintaining sealing performance over time.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of fixing the sealing element to the housing and having it slide against the displacement spiral base, the invention inverts the arrangement by fixing the sealing element to the displacement spiral base and having it slide against a stationary sliding plate. This inversion allows the sealing element to move with the displacement spiral while maintaining a stable sealing surface.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If the sealing element is fixed in the housing, then sealing performance is improved, but maintenance complexity increases due to additional replacement steps

Engineering Contradiction:
Improvesealing performanceVSAvoidmaintenance complexity
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The sealing element is merged with the displacement spiral base by fixing it to the base, creating a combined assembly. This allows the sealing element to be replaced together with the displacement spiral as a single unit, eliminating the need for separate seal replacement procedures and reducing maintenance complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the displacement spiral orbits over the seal to ensure proper compression chamber sealing, then compression chamber gas tightness is improved, but oil present in the drive segment is drawn over the seal into the compression chamber

Engineering Contradiction:
Improvecompression chamber gas tightnessVSAvoidoil ingress into compression chamber
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The sliding plate serves as a mediator that separates the drive area (where oil is present) from the compression area. The sliding plate is positioned such that it prevents oil from the drive segment from being drawn over into the compression chamber, while still allowing the displacement spiral to orbit properly for maintaining compression chamber gas tightness.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design effectively prevents oil ingress into the compression chamber, maintains long-term sealing performance, reduces maintenance complexity, and enables high-pressure compressed air generation suitable for compressed air brake systems.

Implementation Method 1

the friction between the displacement spiral base and the ring seal can lead to increased wear of the ring seal

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The wiper element can be designed to wipe away oil residues that may accumulate on the sliding plate

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

The compression chamber can be water-cooled

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4264053B1Scroll compressor for generating oil-free compressed air
Publication Date: 2025.11.26 OET GMBH
  • EP4264053B1 patent drawingFigure 1
  • EP4264053B1 patent drawingFigure 2
  • EP4264053B1 patent drawingFigure 3~4

AI summary

A scroll compressor for generating oil-free compressed air, in particular for a compressed air brake system of a lorry, with a drive which is arranged in a housing (4) and is connected to an orbiting displacer scroll (31, 32) which has a displacer scroll bottom (39) and a displacer scroll wall (38), wherein the displacer scroll wall (38) engages into a stationary mating scroll (21, 22), with the result that at least one variable compression chamber (30) is formed between the displacer scroll (31, 32) and the mating scroll (21, 22), wherein a seal element (33) is provided between the displacer scroll (31, 32) and the housing (4), and wherein the seal element (33) is fastened in the displacer scroll bottom (39) and seals against a sliding plate (26) which is connected fixedly to the housing (4). A compressed air brake system with a scroll compressor of this type.