Compressor Thrust Bearing Washer Locking for High-Speed Reliability

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Solution Overview

Problem

Conventional reciprocating compressors face challenges in minimizing friction loss and maintaining reliability at high speeds due to the limitations of existing ball bearing designs, particularly in miniaturized compressors where the ball bearing fails to stably support loads and experiences intermittent rotation due to decreased contact area and viscosity at high speeds.

Innovation Solution

A reciprocating compressor design that incorporates a ball bearing assembly with a rotation preventing portion, featuring washers with specific surface features such as straight lines, polygons, or protrusions to prevent relative rotation between the washer and the thrust surfaces, ensuring stable ball rotation and uniform force application even at high speeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a conventional ball bearing is used in a miniaturized compressor, then the compressor size is reduced, but the ball bearing cannot stably support the load transmitted through the crankshaft

Engineering Contradiction:
Improvecompressor sizeVSAvoidload support stability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The invention introduces asymmetric features on the washer surfaces (protrusions, recesses, or patterns) that create directional constraints. This asymmetry prevents the washer from rotating relative to the thrust surface while maintaining compact dimensions, thereby resolving the contradiction between miniaturization and load support stability

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The rotation preventing portion is pre-configured on the washer or thrust surface before operation begins. This preliminary structural arrangement ensures that the washer cannot rotate under load conditions, providing stable load support from the outset without requiring active control mechanisms

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the compressor operates at high speed, then productivity increases, but the contact area between the washer and thrust surface decreases causing intermittent rotation

Engineering Contradiction:
Improvecompressor speedVSAvoidwasher rotation stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The asymmetric rotation preventing features create mechanical interlocking that is independent of operating speed. Unlike viscous forces that diminish at high speeds, the geometric constraints of the asymmetric features maintain their effectiveness regardless of compressor speed, preventing intermittent rotation

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention replaces the speed-dependent viscous adhesion mechanism with a speed-independent mechanical constraint system. The rotation preventing portion provides positive mechanical engagement that does not rely on oil viscosity or contact pressure, ensuring reliable washer positioning at all operating speeds

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Volume of moving object

If the contact area between the washer and thrust surface is small, then the ball bearing can be miniaturized, but the viscous force acting on the washer decreases allowing rotational force to overcome it

Engineering Contradiction:
Improveball bearing sizeVSAvoidviscous force on washer
Core Design Contradiction:
Volume of moving objectVSForce

Solution Approach 1:

The invention substitutes the weak viscous adhesive force with a strong mechanical constraint force. The rotation preventing portion creates direct mechanical engagement between the washer and thrust surface, replacing the insufficient viscous holding force with a robust geometric constraint that does not depend on contact area or oil viscosity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The washer assembly combines multiple functional elements (balls, cage, and rotation preventing features) into a composite structure. This composite design integrates load support, rotation prevention, and positioning functions into a single compact unit that overcomes the limitations of small contact area

Inventive Principle:
Principle #40Composite materials

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 prevents washer rotation relative to the thrust surfaces, enhancing the reliability and performance of the compressor by maintaining stable operation and uniform force application, even at high speeds and in miniaturized formats.

Implementation Method 1

a crankshaft having a shaft coupled to the rotor and inserted into a shaft hole of a cylinder block, an eccentric mass formed eccentrically at an end of the shaft, and a pin that is formed eccentrically with respect to the shaft on a surface of the eccentric mass and rotates eccentrically about the shaft; a connecting rod rotatably coupled to the pin to convert rotational motion into linear motion; a piston rotatably coupled to the connecting rod and configured to compress the refrigerant while reciprocating in a straight line

Methodology Applied
Scientific EffectMechanical conversion (rotational to linear motion):

Implementation Method 2

a ball bearing positioned between the cylinder block and the crankshaft, wherein the ball bearing includes a ball cage; a plurality of balls rotatably coupled to the ball cage; and at least one washer positioned at least one of between the cylinder block and the plurality of balls and/or between the crankshaft and the plurality of balls

Methodology Applied
Scientific EffectFriction reduction through ball bearing mechanism: Ball Bearing

Implementation Method 3

A rotation preventing portion is provided configured to limit rotation of the at least one washer with respect to the cylinder block and/or the crankshaft

Methodology Applied
Scientific EffectMechanical constraint through geometric features:

Data Source

PatentEP4293223A1Reciprocating compressor
Publication Date: 2023.12.20 LG ELECTRONICS INC
  • EP4293223A1 patent drawingFigure 1~2
  • EP4293223A1 patent drawingFigure 3~4
  • EP4293223A1 patent drawingFigure 5~6

AI summary

A reciprocating compressor may include a ball bearing positioned between a thrust surface of a cylinder block and a thrust surface of a crankshaft. The ball bearing may include a ball cage in a ring shape, a plurality of balls rotatably coupled to the ball cage, at least one washer positioned at least one of between the thrust surface of the cylinder block and the plurality of balls and between the thrust surface of the crankshaft and the plurality of balls, and a rotation preventing portion that limits rotation of the washer with respect to the corresponding thrust surface. According to a reciprocating compressor having the rotation preventing portion, as relative rotation of the washer with respect to the thrust surface of the cylinder block and/or the thrust surface of the crankshaft is restrained even if a rotational force higher than a viscous force acting on the washer is applied because a viscosity of oil is lowered, it is possible to eliminate the problem of deterioration of reliability and performance of the compressor.