Scroll Compressor Posture Control for Bearing Load Stability

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In scroll compressors, the inclination of the rotary shaft leads to partial contact between the slider portion and the orbiting bearing, causing reduced load capacity and operation failures due to abrasion and seizure, as the existing technologies do not effectively minimize this inclination.

Innovation Solution

The scroll compressor design incorporates a hemispherical contact portion on the eccentric shaft portion, which acts as a posture control unit to maintain the slider portion parallel to the orbiting bearing, ensuring symmetric oil film pressure distribution and minimizing contact with the bearing, thus preventing inclination and associated failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the rotary shaft is bent and inclined, then the operating frequency increases, but the slider portion inclines toward the orbiting bearing causing partial contact and reduced load capacity

Engineering Contradiction:
Improveoperating frequencyVSAvoidload capacity of orbiting bearing
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

A posture control unit is introduced as an intermediary component between the eccentric shaft portion and the slider portion. This unit includes a contact portion on the eccentric shaft and a contact surface on the slider, creating a mechanical linkage that actively controls the slider's posture to remain parallel to the orbiting bearing even when the rotary shaft is inclined, thereby preventing partial contact and maintaining reliable load capacity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the geometric parameters of the contact portion and contact surface to achieve optimal posture control. By carefully designing the relative positions and orientations of these contact elements, the system compensates for shaft inclination and maintains the slider parallel to the bearing, resolving the contradiction between high-speed operation and bearing reliability

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the balance weight-equipped slider is used to cancel centrifugal force, then the orbital stability improves, but the oil film pressure distribution becomes biased causing slider inclination

Engineering Contradiction:
Improveorbital stabilityVSAvoidslider posture orientation
Core Design Contradiction:
Stability of the object's compositionVSShape

Solution Approach 1:

The posture control unit acts as a mechanical intermediary that decouples the effects of centrifugal force imbalance from slider inclination. The contact portion and contact surface create a constraint mechanism that maintains proper slider orientation despite the biased oil film pressure distribution caused by the balance weight configuration

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The contact portion is designed with a curved surface that contacts the slider's contact surface, creating a point or line contact that effectively controls the slider's rotational degree of freedom. This curved contact geometry allows the posture control unit to maintain slider parallelism while accommodating the dynamic forces from the balance weight mechanism

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 configuration effectively minimizes partial contact between the slider and orbiting bearing, maintains the load capacity of the orbiting bearing, and prevents abrasion and seizure, ensuring stable operation by maintaining the slider's posture parallel to the orbiting bearing.

Implementation Method 1

a contact portion 6f having a hemispherical shape is provided on the eccentric shaft portion 6a at a position corresponding to a central portion in the axial direction of the orbiting bearing 2d

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

an oil film pressure distribution generated by lubricant is substantially biased in the axial direction

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3156652B1Scroll compressor
Publication Date: 2019.12.04 MITSUBISHI ELECTRIC CORP
  • EP3156652B1 patent drawingFigure 1
  • EP3156652B1 patent drawingFigure 2~3
  • EP3156652B1 patent drawingFigure 4(a)~5

AI summary

A posture control unit (contact portion 6f) that controls a posture of a balance weight-equipped slider (5) so that a slider portion (5a) of the balance weight-equipped slider (5) maintains the posture parallel to an orbiting bearing (2d) is provided at a position corresponding to a central portion in an axial direction of the orbiting bearing (2d) between an eccentric direction-side side surface of an eccentric shaft portion (6a) of a rotary shaft (6) and an inner wall surface of a slide hole (5aa) facing the side surface.