Pneumatic Vane Motor Double Seal Ring Arrangement
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Solution Overview
Problem
Pneumatic vane motors face challenges in maintaining a durable and tight seal between the stator and output shaft to prevent air leakage, as existing elastic ring seals require high clamp force, leading to rapid mechanical wear, reduced efficiency, and shortened service life due to frictional losses.
Innovation Solution
A double seal ring arrangement with a low pressure chamber and check valves is implemented, reducing the pressure on the seal ring and minimizing friction, allowing for a light fit and effective air leakage prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elastic ring seal means are used with heavy clamp force to prevent air leakage, then sealing tightness is improved, but frictional resistance and mechanical wear increase
Solution Approach 1:
The seal system is divided into two separate seal rings (first seal ring and second seal ring) positioned at different locations. The first seal ring engages with the output shaft while the second seal ring engages with the stator, distributing the sealing function across multiple elements rather than relying on a single seal under high clamp force.
Solution Approach 2:
A low pressure chamber is introduced as an intermediary space between the two seal rings and the high pressure cylinder. This chamber acts as a buffer that isolates the seal rings from direct exposure to high air pressure, allowing them to operate with reduced clamp force while maintaining effective sealing.
2Reliability
If elastic ring seal means are used with heavy clamp force to prevent air leakage, then sealing tightness is improved, but service life of the seal is reduced
Solution Approach 1:
The sealing function is segmented into two separate seal rings operating in a distributed manner, reducing the mechanical stress and wear on each individual seal ring compared to a single seal under heavy clamp force.
Solution Approach 2:
The low pressure chamber serves as a protective intermediary that shields the seal rings from direct exposure to high air pressure and mechanical wear, thereby extending their service life while maintaining sealing effectiveness.
3Reliability
If elastic ring seal means are used with heavy clamp force to prevent air leakage, then sealing tightness is improved, but motor efficiency is reduced
Solution Approach 1:
By segmenting the sealing function into two separate seal rings, the system reduces the total frictional resistance compared to a single seal under heavy clamp force, thereby improving motor efficiency while maintaining sealing tightness.
Solution Approach 2:
The low pressure chamber acts as a mediator that reduces the operational load on the seal rings, minimizing frictional losses and improving overall motor efficiency while preserving effective sealing.
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 solution provides a tight seal against air leakage with low friction characteristics, extending the service life of the seal and maintaining motor efficiency by reducing frictional losses.
Implementation Method 1
when the pressure within the low pressure chamber is higher than the pressure in the communication passage presently acting as outlet passage the valve element will yield radially and uncover the opening, thereby letting through an air flow towards the passage. If on the other hand the pressure in the passage is higher than that in the low pressure chamber due to connection of port to the pressure air source the valve element will be deformed in the opposite direction and close the opening
Implementation Method 2
those seal rings, due to the heavy clamp force, generate considerable frictional resistance and is mechanically worn down rather rapidly
Data Source
AI summary
A pneumatic vane motor includes a stator with a cylinder, an inlet connectable to a pressure air source and an outlet connectable to an exhaust passage, a rotor journalled in the stator, and an output shaft. The stator has a front opening forming a clearance seal relative to the output shaft and an annular front cover with at least one elastic annular seal element encircling the output shaft at a distance from the clearance seal, wherein a low pressure chamber is formed between the clearance seal and the seal element or elements and communicates with the exhaust passage.