Spring Brake Actuator Diaphragm Contour for Pressure Plate Stability
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Solution Overview
Problem
Conventional spring brake actuators are prone to wear over time, leading to radial shifting of the pressure plate with respect to the flexible diaphragm, which complicates servicing and reduces the actuator's longevity and efficiency.
Innovation Solution
A flexible diaphragm with a contoured portion that abuts and wraps around the pressure plate's radially outer diameter, preventing radial shifting by forming a pocket that secures the pressure plate in place, thereby inhibiting displacement and enhancing the actuator's robustness and longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional spring brake actuator is used without a contoured portion on the flexible diaphragm, then the structure is simpler and easier to manufacture, but the pressure plate undergoes radial shifting over time due to wear, reducing reliability and increasing maintenance needs
Solution Approach 1:
The flexible diaphragm incorporates a contoured portion with a curved surface that complements the radially outer diameter of the pressure plate. This curved geometry creates a pocket that receptively holds the pressure plate, preventing radial shifting while the diaphragm flexes during operation. The contoured portion's curvature is specifically designed to match the pressure plate's outer diameter, ensuring stable positioning without adding complex mechanical fasteners or rigid constraints.
2Reliability
If the flexible diaphragm is made rigid to prevent radial shifting, then the pressure plate stability improves, but the diaphragm loses its flexibility and ability to respond to pneumatic pressure changes
Solution Approach 1:
The flexible diaphragm is designed with non-uniform local properties: the majority of the diaphragm surface remains flexible to respond to pneumatic pressure, while the contoured portion featuring the pocket has enhanced structural characteristics. This localized reinforcement at the pressure plate interface provides stability precisely where needed, without compromising the overall flexibility of the diaphragm required for pneumatic actuation.
3Reliability
If wear-resistant materials are used for the pressure plate and diaphragm interface, then radial shifting is reduced, but manufacturing costs increase and the components become harder to service
Solution Approach 1:
Instead of attempting to prevent wear through expensive specialized materials, the invention accepts that wear will occur but designs the contoured pocket to accommodate and compensate for wear. The pocket's geometry allows the pressure plate to remain centered even as minor wear occurs at the interface, converting the harmful effect of wear into a non-critical condition that does not compromise reliability or require expensive materials.
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 contoured flexible diaphragm design effectively prevents radial shifting of the pressure plate, reducing wear and maintenance costs while enhancing the spring brake actuator's durability and operational efficiency.
Implementation Method 1
a main compression spring in the parking brake chamber
Implementation Method 2
a flexible diaphragm in the parking brake chamber
Data Source
AI summary
A spring brake actuator is for braking a wheel of a vehicle. The spring brake actuator has an axially elongated housing having a parking brake chamber and a service brake chamber; a main compression spring in the parking brake chamber; a flexible diaphragm in the parking brake chamber; and a pressure plate in the parking brake chamber, the pressure plate located axially between the main compression spring and the flexible diaphragm. The flexible diaphragm has a contoured portion that inhibits radial shifting of the pressure plate with respect to the flexible diaphragm.