Scroll Compressor Back-Pressure Chamber Size Reduction
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Solution Overview
Problem
Existing scroll fluid machines face challenges in minimizing thrust loads and maintaining sealing reliability due to the size increase caused by the doughnut-shaped back-pressure chamber and the need for multiple seal members, which degrades performance.
Innovation Solution
A scroll fluid machine design that integrates a back-pressure chamber forming member with the casing, allowing for a larger pressure-receiving area without increasing size, using a single seal member and positioning the orbiting bearing on the coupling member, and providing a rotation preventing mechanism between the coupling member and the casing to reduce overall dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the orbiting bearing is provided on the center of the back of the orbiting scroll member, then the structure is simplified, but the pressure-receiving area of the back-pressure chamber is reduced to a doughnut-shape area around the orbiting bearing, requiring increased radial size to achieve sufficient area
Solution Approach 1:
The orbiting bearing is extracted from the orbiting scroll member and relocated to the coupling member. This extraction removes the constraint that created the doughnut-shaped back-pressure chamber, allowing the back-pressure chamber to be redesigned with a full circular pressure-receiving area without the bearing occupying the center space.
2Reliability
If the orbiting bearing is provided on the center of the back of the orbiting scroll member, then the coupling structure is simplified, but two seal members different in diametrical size are needed to hermetically seal the back-pressure chamber, degrading sealing performance
Solution Approach 1:
By extracting the orbiting bearing from the orbiting scroll member and relocating it to the coupling member, the back-pressure chamber is transformed from a doughnut shape to a full circular shape. This geometric change allows the chamber to be sealed with a single seal member of uniform diameter, eliminating the need for two different seal members and improving sealing reliability.
3Volume of moving object
If the bearings of the auxiliary cranks are provided between the orbiting scroll member and the fixed scroll member, then the rotation preventing mechanism is integrated, but the bearings must be disposed radially outward of the wrap portions, causing the compressor to increase in size diametrically
Solution Approach 1:
The orbiting bearing is extracted from the orbiting scroll member and transferred to the coupling member. This relocation allows the bearing to be positioned in a space that does not interfere with the wrap portions of the scroll members, eliminating the need to dispose bearings radially outward and reducing the compressor's diametrical size.
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 minimizes thrust loads, enhances sealing reliability, and reduces the compressor's size while maintaining efficient compression, allowing for improved performance and increased pressure-receiving area without the need for multiple seal members.
Implementation Method 1
a part of the compressed air is introduced into the back-pressure chamber, thereby reducing the thrust load by the pressure created in the back-pressure chamber
Implementation Method 2
The coupling member is coupled to the rotating shaft through an orbiting bearing
Data Source
AI summary
A scroll fluid machine is capable of readily providing a back-pressure chamber having an increased pressure-receiving area and yet capable of being reduced in size. A fixed scroll member is secured to a casing. An orbiting scroll member is provided at a position facing the fixed scroll member. A holder is provided at the back of the orbiting scroll member, and a coupling member is provided to face the orbiting scroll member across the holder. The coupling member couples together the orbiting scroll member and a driving shaft and performs an orbiting motion together with the orbiting scroll member. A back-pressure plate is provided at the back of the orbiting scroll member, and a back-pressure chamber is formed between the back-pressure plate and the holder.