Spring Brake Cylinder Seal with Diverging Flow Section
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Solution Overview
Problem
Existing pneumatic spring-actuated brake cylinders experience disturbing whistling noises due to turbulent air flows when compressed air escapes from the spring chamber into the brake chamber, which current sealing solutions have not adequately addressed.
Innovation Solution
The sealing element's active surface against the brake cylinder is designed with a diverging cross-section that reduces turbulence by creating a continuous divergence from the spring chamber into the brake chamber, and a guide ring made of stiffer material is used to enhance the sealing arrangement, including a radially elastic guide ring and a circumferential projection for improved sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If compressed air flows from the spring chamber into the brake chamber through the sealing gap, then the brake chamber can be pressurized, but disturbing whistling noises occur due to turbulent air flow
Solution Approach 1:
A guide ring is introduced as an intermediary component between the spring chamber and brake chamber. This guide ring with its specific geometry (radially outer recesses extending in the axial direction) acts as a flow mediator that guides the compressed air in a controlled manner, reducing turbulence and the associated whistling noises while still allowing pressure equalization between chambers
Solution Approach 2:
The patent modifies the flow parameters by changing the geometry of the flow path. The radially outer recesses in the guide ring alter the flow cross-section and flow direction, transforming the turbulent flow regime into a more laminar flow regime, thereby reducing noise generation while maintaining the pressure equalization function
2Adaptability or versatility
If the sealing element uses elastomer material for flexibility, then the seal can adapt to pressure changes, but the material stiffness is insufficient to adequately reduce flow noise
Solution Approach 1:
The patent employs a composite sealing system combining elastomer material for the sealing element (providing flexibility and adaptability to pressure changes) with a rigid guide ring structure (made of metal or rigid plastic) that provides flow guidance and noise reduction. This composite approach leverages the advantages of both material types to simultaneously achieve sealing adaptability and noise reduction
3Object-generated harmful factors
If axial grooves are provided in the sealing element to redirect air flow, then some noise reduction is achieved, but the noise level remains above acceptable levels
Solution Approach 1:
The patent segments the flow control function by separating it from the sealing element and assigning it to a dedicated guide ring component. This segmentation allows the guide ring to be optimized specifically for flow guidance and noise reduction without compromising the sealing element's primary sealing function, thereby achieving better noise reduction while maintaining sealing reliability
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 configuration significantly reduces disruptive flow noise by minimizing turbulence and enhancing the sealing effect, providing a more effective solution to the noise issue compared to previous designs.
Implementation Method 1
the radially outer leg (64) sealing against the running surface (54) of the spring-actuated brake cylinder (4)
Implementation Method 2
a cross-section that diverges continuously as viewed in the direction of flow from the spring chamber (14) into the spring-actuated brake chamber (12)
Implementation Method 3
a dovetail-shaped cross-section with two radially elastically expanding legs (64, 66)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The cylinder (1) has a spring brake piston (8) actuatable by a loaded spring that is arranged in a spring chamber (14). The piston is adjustable in a releasing- or application position by aeration or deaeration of a spring brake chamber (12). An operating surface (76) of a side piece (64) of a sealing element (62) of a sealing arrangement is formed such that an intermediate space (77) between the operating surface and a contact surface (54) of a spring brake cylinder (4) has diverging cross-section in a flow direction from the spring chamber into the spring brake chamber.