PEEK Bush Bearing for Scroll Compressor Eccentric Load Reduction

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Solution Overview

Problem

In scroll compressors, a large height difference between the supporting point and action point of the rotational shaft leads to increased eccentric load, friction loss, noise, and reduced compression efficiency, limiting compressor capacity and increasing material costs.

Innovation Solution

A bush bearing is integrated between the rotational shaft and the orbiting scroll, reducing the eccentric load by minimizing the height difference and using a polyether ether ketone (PEEK) material with a suitable thermal expansion coefficient to maintain contact and prevent detachment, thereby enhancing reliability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the height difference between supporting point and action point of rotational shaft is reduced, then friction loss and noise are reduced, but device complexity increases due to bush bearing integration

Engineering Contradiction:

Improvefriction lossVSAvoiddevice complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The bush bearing is integrated by merging the supporting point and action point of the rotational shaft into a single location. This eliminates the height difference between these points, thereby reducing friction loss and noise while avoiding the need for separate supporting structures that would increase device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bush bearing acts as an intermediary component that enables the rotational shaft to be supported at its action point. This intermediary structure allows the shaft to rotate with minimal friction and noise without requiring complex external support mechanisms.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If bush bearing material thermal expansion coefficient matches orbiting scroll, then contact is maintained and reliability increases, but material selection is limited

Engineering Contradiction:

ImprovereliabilityVSAvoidmaterial selection flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention specifies that the bush bearing material should have a thermal expansion coefficient within 0.5 to 5 times that of the orbiting scroll. This parameter range ensures that the bush bearing maintains reliable contact with the orbiting scroll across temperature variations while providing sufficient flexibility in material selection to balance reliability with other design requirements.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If main frame axial length is minimized, then compressor capacity increases, but manufacturing precision requirements increase

Engineering Contradiction:

Improvecompressor capacityVSAvoidmanufacturing precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The bush bearing creates an equipotential condition by aligning the supporting point and action point of the rotational shaft at the same axial location. This eliminates gravitational and mechanical potential differences that would otherwise require longer support structures, enabling compact main frame design while maintaining manufacturing feasibility through simplified alignment requirements.

Inventive Principle:

Principle #12Equipotentiality

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 bush bearing reduces friction loss, noise, and material costs, while increasing the compressor's reliability and capacity by minimizing the axial length and weight of the main frame, and allowing for a higher motor stack within the same axial length.

Implementation Method 1

reducing the eccentric load by minimizing the height difference and using a polyether ether ketone (PEEK) material with a suitable thermal expansion coefficient to maintain contact and prevent detachment, thereby enhancing reliability and efficiency

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

using a polyether ether ketone (PEEK) material with a suitable thermal expansion coefficient to maintain contact and prevent detachment

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS9897143B2Bush bearing and a scroll compressor including a bush bearing

Publication Date: 2018.02.20 LG ELECTRONICS INC

AI summary

A bush bearing and a scroll compressor including a bush bearing are provided. A boss of an orbiting scroll may be inserted into and coupled to a boss coupling groove of a rotational shaft, and thus, an outer circumferential surface of a bush bearing may wholly contact an inner circumferential surface of the boss coupling groove, thereby decreasing wear of the bush bearing. Further, friction loss in the bush bearing may be reduced, and thus, compression efficiency and reliability may be enhanced, noise may be reduced, and material costs may be reduced. Furthermore, despite that the bush bearing is formed in a ring shape and press-fitted to the boss, as the bush bearing may be formed of a plastic material having an ether ketone bonding in consideration of a thermal expansion rate, an elongation, and a press-fit range, the bush bearing may be effectively prevented from being detached from the boss, thereby enhancing a reliability of a compressor.