Scroll Compressor Lip Seal with Communication Passage for Pressure Equalization
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Solution Overview
Problem
Existing scroll fluid machines face lubricant leakage issues due to increased pressure within the orbiting bearing housing, particularly at high rpm and high load operations, as existing seal designs are prone to leakage when the internal pressure rises due to temperature increases or clogging of breathing holes.
Innovation Solution
A scroll fluid machine design featuring a seal member with a lip seal and communication passages that includes protrusions angled with respect to the axis, which creates a pumping action to direct lubricant back into the orbiting bearing and prevents leakage, while maintaining a sealed space at atmospheric pressure through the use of a communication passage between the orbiting bearing and the seal member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hermetically enclosed space is created by seal lips to prevent lubricant leakage, then sealing performance is improved, but internal pressure increases due to temperature rise or clogging, causing stepwise leakage from the seal lip
Solution Approach 1:
The hermetically enclosed space is divided into two separate spaces by the communication passage: a first space between the orbiting bearing and seal member, and a second space on the opposite side of the seal member. This segmentation allows pressure equalization while maintaining sealing functionality, preventing the pressure buildup that causes stepwise leakage.
Solution Approach 2:
The communication passage acts as an intermediary channel connecting the two spaces. It allows controlled communication between the high-pressure bearing space and the lower-pressure external space, enabling pressure equalization without compromising the sealing action of the lip seal against the drive shaft.
2Stress or pressure
If breathing holes are provided in the seal structure to equalize pressure, then pressure balance is improved, but lubricant leakage occurs when the breathing holes become clogged
Solution Approach 1:
The communication passage serves as a more reliable intermediary compared to traditional breathing holes. It is integrated into the lip seal structure itself, making it less susceptible to clogging while still providing effective pressure equalization between the bearing space and external environment.
Solution Approach 2:
The communication passage is pre-formed in the lip seal structure during manufacturing, ensuring proper positioning and geometry before operation. This preliminary formation prevents the misalignment or blockage issues that can occur with post-manufacturing breathing hole configurations.
3Reliability
If protrusions are added to the lip seal to create pumping action, then lubricant movement toward the bearing is improved, but device complexity increases
Solution Approach 1:
The pumping action is achieved through local modifications to the lip seal surface with protrusions positioned at specific locations and angles. This localized feature creation maintains the overall simplicity of the seal structure while providing the necessary lubricant pumping function toward the orbiting bearing.
Solution Approach 2:
The protrusions on the lip seal create a dynamic pumping action that activates during rotation. As the seal rotates with the drive shaft, the angled protrusions automatically pump lubricant toward the bearing without requiring additional mechanical components, converting rotational motion into useful lubricant delivery.
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 minimizes lubricant leakage even at high operational conditions, ensuring reliable sealing and maintaining the orbiting bearing's lubricated condition without the need for additional tight-binding mechanisms, thus enhancing the reliability and assembly efficiency of the scroll fluid machine.
Implementation Method 1
The seal member has a lip seal producing action of moving the lubricant toward the orbiting bearing by rotation of the drive shaft
Data Source
AI summary
A scroll fluid machine with ensured reliability of an oil seal and a bearing even in a compressor operation at high rpm and high load is provided, which includes: a fixed scroll; an orbiting scroll facing the fixed scroll and having a boss provided on a face opposite to the fixed scroll; a drive shaft having a leading end mounted to the boss; an orbiting bearing supporting the drive shaft in connection with the orbiting scroll; and a seal member placed between the boss and the drive shaft to seal against a lubricant supplied to the orbiting bearing. The seal member has an oil lip producing action of moving the lubricant toward the orbiting bearing by rotation of the drive shaft. A communication passage is provided in the oil lip for communication between a space between the orbiting bearing and the seal member and a space outside the boss.