Inductive Brake Pedal Sensor Slider for Constant Air Gap Accuracy
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Solution Overview
Problem
Existing inductive displacement sensors for vehicle brake pedals face challenges in maintaining precise positioning and repeat accuracy due to air gap variations and material tolerances, leading to reduced performance and comfort in braking systems.
Innovation Solution
An inductive linear displacement sensor arrangement with a slider guided by two parallel cylindrical guide elements, ensuring a constant air gap and minimizing tilting and twisting, using materials with low tolerances and precise manufacturing to maintain accurate positioning over the sensor's lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a cylindrical guide rod and plastic support structure are used for linear guiding and positioning, then the structure is simple and easy to manufacture, but positioning accuracy and repeat accuracy deteriorate due to material pairing tolerances and air gap variations
Solution Approach 1:
The patent changes the material parameters by replacing plastic with metal (aluminum or steel) for the guide rod and support structure. This material substitution reduces thermal expansion coefficients and improves dimensional stability, thereby maintaining tighter tolerances and more consistent air gaps over temperature variations and time, directly resolving the positioning accuracy issue while keeping the cylindrical guide rod design for manufacturability
Solution Approach 2:
The patent employs cylindrical (curved) guide rods instead of linear or flat guidance structures. The cylindrical geometry provides uniform radial clearance and allows for self-centering of the moving components, reducing friction and wear while maintaining consistent positioning accuracy throughout the stroke, thus achieving both ease of manufacture and high positioning precision
2Device complexity
If a cylindrical guide rod and plastic support structure are used for linear guiding, then the device complexity is low, but repeat accuracy deteriorates over the service life due to wear and tolerance accumulation
Solution Approach 1:
The patent uses composite material construction with metal guide rods (aluminum or steel) combined with precision-machined metal support structures. This composite metallic approach eliminates the incompatible thermal and mechanical properties of plastic-metal pairings, reducing differential expansion and wear rates, thereby maintaining repeat accuracy throughout the service life without increasing device complexity
Solution Approach 2:
The patent incorporates pre-lubricated cylindrical guide rods with controlled surface finishes and tight tolerances from the manufacturing stage. The precision machining and initial lubrication provide a cushioning effect that compensates for future wear, ensuring that repeat accuracy is maintained throughout the operational life of the sensor arrangement
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 provides precise and stable detection of brake pedal position, enhancing the performance and comfort of braking systems by maintaining a constant air gap and reducing mechanical wear, thus improving the accuracy and reliability of brake control.
Implementation Method 1
the predominant part of the printed circuit board having at least one excitation structure and at least one receiving structure... enables precise position determination of the at least one coupling device or a corresponding movable body via the eddy current effect
Implementation Method 2
at least one excitation structure and at least one receiving structure... evaluation and control unit is designed to evaluate at least one measurement signal induced in the at least one receiving structure
Data Source
AI summary
An inductive linear displacement sensor arrangement includes a movable coupling device coupled to a movable body, an electrically conductive coupling element, and a stationary circuit carrier. The circuit carrier includes an excitation structure and a receiving structure, which extend along a displacement path of the coupling device. An evaluation and control unit is designed to evaluate a measurement signal induced in the receiving structure and to determine the current position of the coupling device and of the body. The coupling device comprises a slider on which the electrically conductive coupling element is arranged. The slider is mounted for sliding movement in a plane of displacement via the path of displacement of the coupling device on two parallel guide elements, one of which guides the slider of the coupling device along the displacement path, and another of which is a sliding guide which prevents the slider from tilting and/or twisting.