Spring Brake Actuator Diaphragm Retainer and Valve Assembly
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Solution Overview
Problem
Conventional pneumatic spring brake actuators face challenges in maintaining the sealing engagement of the diaphragm with the push rod and pressure plate, especially under pressurized conditions, which can lead to disengagement of emergency or parking brakes.
Innovation Solution
A brake actuator assembly featuring a retainer that engages the push rod's protrusion, ensuring the diaphragm remains coupled between the pressure plate and retainer, with a bearing that threads onto the push rod to provide a secure seal and a one-way valve assembly to regulate air flow, preventing pressurization of the spring chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the diaphragm sealingly engages the push rod and pressure plate to seal the pressure chamber from the spring chamber, then the emergency or parking brakes can be disengaged by pressurization of the pressure chamber, but the diaphragm may become disengaged from the pressure plate when pressurized air exerts force on the opposite side, leading to failure of brake disengagement
Solution Approach 1:
The retainer is pre-installed on the push rod to establish preliminary mechanical engagement that prevents the diaphragm from becoming disengaged during pressurization. This preliminary structural arrangement ensures the diaphragm remains properly positioned and sealed to the pressure plate even when subjected to opposing pressurized air forces, thereby preventing brake disengagement failure without requiring complex additional mechanisms
Solution Approach 2:
The retainer acts as a protective element that anticipates and prevents the harmful effect of diaphragm disengagement. By providing this preliminary protective structure, the system compensates for the potential failure mode where pressurized air forces could push the diaphragm away from the pressure plate, ensuring continuous sealing engagement and reliable brake control
2Stress or pressure
If the spring chamber is vented to prevent pressurization, then the spring chamber pressure can be controlled, but water and contaminants may enter the spring chamber through the vent opening
Solution Approach 1:
The valve assembly acts as an intermediary element between the spring chamber and the external environment. It provides a controlled fluid flow path that allows the spring chamber to be vented and pressure-controlled while preventing water and contaminants from entering. The valve mechanism selectively permits air flow while blocking harmful contaminants, thus mediating between the conflicting requirements of pressure control and contamination prevention
3Stress or pressure
If the valve assembly is placed in the push rod to regulate air flow between the spring chamber and service brake pressure chamber, then air flow can be controlled to vent the spring chamber, but the valve assembly adds complexity to the push rod structure
Solution Approach 1:
The valve assembly is merged with the push rod structure, integrating the air flow regulation function directly into the existing push rod component. This combination allows the valve to be positioned within or on the push rod, enabling air flow control between the spring chamber and service brake pressure chamber while minimizing additional structural complexity by utilizing the push rod as part of the valve assembly housing or mounting structure
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 maintains the sealing engagement of the diaphragm, preventing disengagement of emergency or parking brakes under pressurized conditions and ensures timely application of brakes by regulating air flow, enhancing the reliability and safety of the brake actuator system.
Implementation Method 1
The diaphragm sealingly engages the push rod and/or pressure plate to seal the pressure chamber from the spring chamber
Implementation Method 2
The retainer engages the protrusion such that at least a portion of the diaphragm is positioned between the pressure plate and the retainer
Implementation Method 3
The push rod preferably frictionally engages the pressure plate
Implementation Method 4
The bearing preferably includes threads that engage threads on an interior surface of the push rod
Implementation Method 5
A valve assembly with a one-way seal valve is preferably coupled to an end of the push rod to allow air to discharge from a spring chamber
Implementation Method 6
The spring chamber contains a large force compression spring that is compressed when the pressure chamber is pressurized and the emergency or parking brakes are not applied
Implementation Method 7
pressurized air exerts a force on a side of the diaphragm that is opposite the retainer
Data Source
AI summary
A brake actuator assembly including a pressure plate presenting an opening, a push rod that is coupled to the pressure plate, a diaphragm that is coupled to the pressure plate, and a retainer that engages the push rod. The push rod has an outer surface and at least one protrusion extending outward from the outer surface. The retainer engages the protrusion such that at least a portion of the diaphragm is positioned between the pressure plate and the retainer.