Brake System Failure Analysis
| Function ID | Function | Potential Failure Mode | Effects | Causes | Current Controls | Severity | Actions | |
|---|---|---|---|---|---|---|---|---|
|
F1
|
Convert driver input
|
Pedal resistance too high
|
Driver fatigue, reduced braking response
|
Pivot binding, return spring stiffness
|
Pedal force testing, lubrication
|
6 |
|
|
Detailed AnalysisOccurrence Rating 4 - Moderate Detection Rating 3 - High Risk Priority Number (RPN) 72 Recommended Actions Redesign pedal pivot with lower friction material, adjust return spring tension Interface Connections
F1.1: Amplify force (Mechanical)
F1.2: Generate pressure (Mechanical)
Attachments |
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|
F1.1
|
Amplify force
|
Insufficient mechanical advantage
|
Increased pedal effort, driver fatigue
|
Incorrect pedal ratio, pivot wear
|
Pedal ratio verification, durability testing
|
7 |
|
|
Detailed AnalysisOccurrence Rating 3 - Low Detection Rating 2 - Very High Risk Priority Number (RPN) 42 Recommended Actions Optimize pedal ratio to provide 5:1 mechanical advantage, implement wear-resistant pivot materials Interface Connections
F1: Convert driver input (Mechanical)
F1.1.1: Provide mechanical advantage (Mechanical)
Attachments |
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|
F1.2
|
Generate pressure
|
Internal leakage in master cylinder
|
Reduced hydraulic pressure, increased pedal travel
|
Seal wear, cylinder bore damage
|
Pressure testing, seal material selection
|
9 |
|
|
Detailed AnalysisOccurrence Rating 3 - Low Detection Rating 4 - Moderate Risk Priority Number (RPN) 108 Recommended Actions Improve seal material durability, implement enhanced cylinder bore surface finish requirements Interface Connections
F1: Convert driver input (Mechanical)
F2: Distribute hydraulic pressure (Hydraulic)
Attachments |
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|
F2
|
Distribute hydraulic pressure
|
External fluid leakage
|
Loss of brake fluid, potential complete brake failure
|
Fitting damage, line corrosion, connection vibration
|
Pressure testing, corrosion protection, secure mounting
|
10 |
|
|
Detailed AnalysisOccurrence Rating 2 - Very Low Detection Rating 5 - Moderate Risk Priority Number (RPN) 100 Recommended Actions Implement double-flare connections, use corrosion-resistant materials, add protective coatings Interface Connections
F1.2: Generate pressure (Hydraulic)
F2.1: Route to front brakes (Hydraulic)
F2.2: Route to rear brakes (Hydraulic)
Attachments |
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|
F3
|
Maintain fluid reservoir
|
Fluid contamination
|
Seal degradation, reduced hydraulic performance
|
Cap seal failure, improper fluid, maintenance error
|
Fluid quality testing, cap seal design
|
7 |
|
|
Detailed AnalysisOccurrence Rating 4 - Moderate Detection Rating 6 - Low Risk Priority Number (RPN) 168 Recommended Actions Improve reservoir cap seal design, add contamination indicator, enhance service instructions Interface Connections
F1.2: Generate pressure (Hydraulic)
F3.1: Store brake fluid (Hydraulic)
Attachments |
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|
F4
|
Provide fail-safe operation
|
Failure detection system malfunction
|
Undetected hydraulic failure, no driver warning
|
Sensor failure, electrical connection issue
|
System self-test, redundant sensors
|
8 |
|
|
Detailed AnalysisOccurrence Rating 2 - Very Low Detection Rating 3 - High Risk Priority Number (RPN) 48 Recommended Actions Implement dual sensor system, add system self-test at vehicle startup, improve electrical connection design Interface Connections
F2: Distribute hydraulic pressure (Hydraulic)
F4.2: Detect system failures (Electrical)
Attachments |
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