Scroll Compressor Back-Pressure Chamber Design for Sealing and Friction Trade-off
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Solution Overview
Problem
Scroll compressors face challenges in balancing leakage prevention and lubrication, as strong contact between the fixed and orbiting scrolls reduces friction but increases leakage, while weak contact reduces friction but increases sealing force loss, and existing solutions like back-pressure chambers can complicate the design and lead to increased size and manufacturing costs.
Innovation Solution
A scroll compressor design where the back-pressure chamber is formed on the main frame rather than the orbiting scroll, allowing for a compact structure and improved alignment accuracy, with the sealing member fixed to neither the orbiting scroll nor the main frame, using a back-pressure chamber to generate pressure for sealing without increasing friction or wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the end of the wrap and the surface of the head plate strongly contact each other, then leakage is prevented, but friction is increased and damage caused by noise and wear is increased
Solution Approach 1:
A back-pressure chamber is introduced as an intermediary space between the compression chamber and the external environment. This chamber receives discharged refrigerant and maintains a pressure that pushes the orbiting scroll against the fixed scroll, providing sealing force without requiring direct strong contact between wrap and head plate surfaces.
Solution Approach 2:
The back-pressure chamber utilizes pneumatic pressure from the discharged refrigerant gas to maintain the orbiting scroll in contact with the fixed scroll. The pressure differential between the back-pressure chamber and the external environment creates a force that ensures sealing while reducing mechanical friction and wear.
2Reliability
If the back-pressure chamber is formed on the orbiting scroll, then sealing pressure is maintained, but the structure becomes complex and the size increases
Solution Approach 1:
The back-pressure chamber is merged with the main frame structure rather than being a separate component on the orbiting scroll. The main frame's lateral wall forms part of the back-pressure chamber, eliminating the need for additional structures and reducing overall device complexity while maintaining sealing pressure.
Solution Approach 2:
The main frame serves multiple functions: it supports the fixed scroll, provides structural housing, and forms part of the back-pressure chamber structure. This multi-functionality reduces the number of separate components needed and simplifies the overall device design.
3Ease of manufacture
If the key groove extends in the radial direction of the head plate, then the Oldham's ring can be coupled, but the head plate size must be increased
Solution Approach 1:
The key groove is repositioned from the radial direction to the axial direction of the head plate. This dimensional change allows the Oldham's ring to be coupled through the thickness of the head plate rather than requiring radial extension, significantly reducing the head plate's radial length while maintaining coupling functionality.
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 reduces the likelihood of tilt and noise caused by orbital movement, minimizes wear on sealing components, and simplifies the manufacturing process by eliminating complex structures, resulting in a compact, high-performance scroll compressor with reduced manufacturing costs.
Implementation Method 1
a back-pressure chamber configured to communicate with the compression chamber
Implementation Method 2
Resistance caused by friction has to be minimized such that the orbiting scroll may smoothly make orbital movements with respect to the fixed scroll
Data Source
AI summary
A scroll compressor is provided in which one of a fixed scroll or an orbiting scroll is provided with at least one guide groove, and the other is provided with a self-rotation prevention member inserted into the at least one guide groove to revolve in the at least one guide groove and configured to prevent self-rotation of the orbiting scroll.