Scroll Compressor Upset Moment Reduction via Pressure Grooves
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Solution Overview
Problem
Existing scroll compressors experience fluctuating upsetting moments due to uneven pushback forces across the orbiting scroll's end plate, leading to increased mechanical stress and potential refrigerant leakage, especially at specific rotational angles.
Innovation Solution
A scroll compressor design incorporating a communicating groove system that alternates between low-pressure and high-pressure states at different rotational angles, using a low-pressure portion filled with fluid of lower pressure than the discharge pressure to attract the orbiting scroll toward the fixed scroll, thereby reducing upsetting moments and preventing excessive pushing forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a pushback mechanism is used to suppress excessive pressing force, then sliding loss is reduced, but upsetting moment increases at certain rotational angles due to uneven pushback force distribution
Solution Approach 1:
The patent applies local quality by creating a low-pressure zone at a specific location on the sliding surface through the communicating groove, rather than uniformly distributing pressure. This localized pressure reduction counteracts the uneven pushback force and reduces the upsetting moment at critical rotational angles while maintaining adequate pressing force in other regions.
Solution Approach 2:
The communicating groove acts as an intermediary mechanism that mediates between the high-pressure pushback force and the orbiting scroll. By introducing low-pressure fluid through the groove, it creates a counterbalancing force that reduces the net upsetting moment without eliminating the necessary pressing force for preventing leakage.
2Reliability
If pressing force is increased to prevent refrigerant leakage, then sealing performance improves, but sliding loss increases due to excessive pressing between scrolls
Solution Approach 1:
The patent uses local quality by applying pressure reduction only at specific locations where upsetting moment occurs, rather than uniformly reducing pressing force across the entire sliding surface. This maintains adequate sealing pressure in critical areas while reducing excessive pressing in areas contributing to upset moment, thereby balancing sealing performance and sliding loss.
3Force
If uniform pushback force is applied across the end plate, then upsetting moment is reduced, but device complexity increases due to additional mechanism requirements
Solution Approach 1:
The patent applies segmentation by dividing the sliding surface into different pressure zones - a low-pressure zone created by the communicating groove and higher-pressure zones in other areas. This segmented pressure distribution achieves upset moment reduction without requiring a completely redesigned uniform pressure mechanism, thus limiting complexity increase.
Solution Approach 2:
The communicating groove essentially copies the function of a complex uniform pressure distribution system by using a simple groove geometry that leverages the existing fluid pressure field. Instead of implementing an active control system for uniform pressure, the groove passive geometry creates the desired pressure distribution pattern.
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 solution effectively stabilizes the orbiting scroll's position across various rotational angles, reducing mechanical stress and preventing refrigerant leakage, while also collecting and reusing lubricating oil to minimize power loss and maintain efficient operation.
Implementation Method 1
a low-pressure portion (12a, 43, 44) filled with a fluid of lower pressure than a discharge pressure of the compression mechanism (40)
Implementation Method 2
a communicating groove (90, 96, 101, 102) formed in a sliding surface of the outer peripheral portion (62) of the fixed scroll (60) so as to communicate with the low-pressure portion (12a, 43, 44)
Implementation Method 3
when high pressure lubricating oil is supplied to the high-pressure groove, a pushback force (separating force) which axially separates both scrolls is generated between the fixed scroll and the orbiting scroll
Data Source
AI summary
A scroll compressor includes a pressing mechanism, a pushback mechanism and an adjustment mechanism. The pressing mechanism applies a pressing force toward a fixed scroll to the back side of an end plate portion of an orbiting scroll. The pushback mechanism applies a pushback force separating the orbiting scroll from a fixed scroll to the front of the orbiting scroll. The adjusting mechanism has a low-pressure portion filled with a fluid of a lower pressure than the discharge pressure of the compression mechanism, and a communicating groove formed in a sliding surface of an outer peripheral portion of the fixed scroll so as to communicate with the low-pressure portion in a first rotational angle range in order to reduce an upsetting moment of the orbiting scroll, and to be blocked from the low-pressure portion in a second rotational angle range other than the first rotational angle range.