Axle Weight Sensing Device for Dynamic Brake Proportioning
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Solution Overview
Problem
Current systems require significant user intervention to properly proportion trailer brakes based on loading conditions, leading to potential over-braking, wheel lockup, and unstable conditions due to incorrect brake settings for varying loads.
Innovation Solution
A vehicle weight sensing system using a strain gauge assembly mounted on an axle tube with a mounting block, which produces a signal to dynamically adjust brake gain in response to the trailer's weight, optimizing braking performance without user intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual brake proportioning is used, then device complexity is reduced, but braking reliability deteriorates due to user error and inability to adapt to varying load conditions
Solution Approach 1:
The brake proportioning system performs self-adjustment based on load conditions. The strain gauge automatically detects axle load and the control system adjusts brake gain without user intervention, eliminating manual adjustment errors while adapting to varying loads
Solution Approach 2:
Manual mechanical adjustment of brake proportioning is replaced with an electronic sensing and control system. The strain gauge assembly and electronic control unit substitute for manual user adjustment, providing automatic adaptation to load changes
2Force
If brake proportioning is adjusted for loaded condition, then braking force is sufficient for heavy loads, but wheel lockup occurs when trailer is empty due to over-proportioned brakes
Solution Approach 1:
The brake proportioning system dynamically adjusts braking force based on real-time load detection. The control system modifies brake gain according to the strain gauge reading, which varies with loading conditions, enabling the same brake system to optimize performance for both empty and loaded states
Solution Approach 2:
The strain gauge provides continuous feedback on axle load to the control system. This feedback loop enables automatic adjustment of brake proportioning, ensuring the braking force is appropriately matched to the actual load condition whether empty or loaded
3Measurement precision
If strain gauge is mounted directly on axle tube, then device complexity is minimized, but measurement precision deteriorates due to structural interference and stress distribution issues
Solution Approach 1:
A mounting block serves as an intermediary between the axle tube and the strain gauge. This intermediate component provides a dedicated interface that isolates the strain gauge from direct contact with the axle tube structure, eliminating structural interference and improving measurement accuracy
Solution Approach 2:
The mounting block is designed with a notch that segments the structure to create a specific stress concentration point. This segmentation allows the strain gauge to measure localized stress that is directly proportional to the applied load, improving measurement precision
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 system ensures proper brake proportioning based on loading conditions, preventing over-braking and wheel lockup, thereby enhancing braking performance and stability by automatically adjusting brake force in real-time.
Implementation Method 1
A strain gauge assembly has a body including raised pads near opposite ends of the body. A thinned section is located between the raised pads. The thinned section of the body includes a strain gauge affixed thereto.
Data Source
AI summary
A vehicle weight sensing system particularly useful for trailers. An axle tube is mounted to the vehicle or trailer through its suspension members that may be leaf springs. A mounting block is affixed to the axle tube for mounting a strain gauge. The mounting block is fixed to the axle tube between the suspension members connected to the axle tube. The mounting block has a mounting surface opposite to the mating surface and a notch extends from the mating surface toward the mounting surface. The notch terminates between the mating surface and the mounting surface. The notch separates rigidified sections of the mounting block and the rigidified sections straddle the notch. The stain gauge measures strain in the axle and thereby generates a signal proportional to the weight on the trailer. The signal can be used to properly proportion a brake system on the trailer.