Vehicle Pedal Rotation Sensing With Offset Magnetic Layout

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Solution Overview

Problem

Existing rotation detection devices for vehicle pedals face challenges with space constraints, accuracy, and calibration, particularly due to the need for strong magnets and precise positioning, which complicates assembly and maintenance.

Innovation Solution

A rotation detection device design featuring a movable magnetic element guided by a radial arm structure that surrounds a stationary magnetic field sensing component, allowing for accurate measurement without requiring the center of the device to be over the axis of rotation, and incorporating self-lubricating materials and adjustable components for easy calibration and reduced friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the centre of the magnetic field sensing component is placed in the centre of rotation of the shaft, then the wear of parts is reduced and accuracy is increased, but the space requirement in axial direction increases

Engineering Contradiction:
ImproveaccuracyVSAvoidspace requirement
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent applies asymmetry by deliberately placing the magnetic field sensing component (second part) at an offset position from the axis of rotation, rather than at the center. This asymmetric arrangement allows the sensor to be positioned in a space-efficient manner while still achieving accurate rotation detection through the magnetic interaction between the offset sensor and the rotating magnetic element.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent transitions from a conventional axial arrangement to a radial arrangement. By positioning the magnetic field sensing component and magnetic element radially outside the axis of rotation, the system utilizes the radial dimension for sensor placement, thereby reducing the axial space requirement while maintaining measurement accuracy through controlled radial positioning.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If strong magnets are used to maintain accuracy after wear, then measurement accuracy is maintained, but the cost increases and control difficulty increases

Engineering Contradiction:
ImproveaccuracyVSAvoidcontrol difficulty
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical wear problem with a magnetic field-based solution. Instead of relying on mechanical contact and strong magnets that are difficult to control, the system uses a magnetic field sensing component that detects the position of a magnetic element. This substitution eliminates mechanical wear issues while maintaining accuracy through non-contact magnetic field interaction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operational parameters by using a magnetic field-based detection system rather than mechanical contact. The system maintains accuracy by controlling the magnetic field interaction parameters (such as the radial position of the magnetic element and the sensing component) rather than relying on mechanical tolerance control, thereby simplifying the overall control requirements.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the distance between sensor and magnet is controlled to maintain accuracy, then measurement accuracy is maintained, but the assembly complexity increases

Engineering Contradiction:
ImproveaccuracyVSAvoidassembly complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges the positioning function into the structural design of the pedal gear. The pedal gear is designed with integrated features (such as radial arms or mounting structures) that automatically position the magnetic element and magnetic field sensing component at the correct radial distances from the axis of rotation. This integration eliminates the need for separate adjustment mechanisms, simplifying assembly while maintaining accurate spacing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system employs self-positioning features where the radial arms or mounting structures of the pedal gear automatically establish the correct radial positioning of the magnetic elements and sensing components during assembly. This self-service mechanism ensures accurate spacing without requiring complex external adjustment tools or procedures, thereby reducing assembly complexity.

Inventive Principle:
Principle #25Self-service

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 a space-saving, high-accuracy rotation detection system that is easy to assemble and calibrate, capable of maintaining accuracy over time by controlling the magnetic element's motion and absorbing tolerances, while minimizing noise and wear.

Implementation Method 1

a magnetic field sensing component/sensor, such as a Hall element

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Implementation Method 2

The magnetic field sensing component can for example be of a Hall or Reed type, which detects the magnetic field

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP2926090B2A rotation detection device and a vehicle pedal comprising such a device
Publication Date: 2023.12.06 CJ AUTOMOTIVE AB
  • EP2926090B2 patent drawingFigure 1
  • EP2926090B2 patent drawingFigure 2a~2c
  • EP2926090B2 patent drawingFigure 3

AI summary

A rotation detection device (1) for detection of rotation of a vehicle pedal (2) around an axis of rotation (A1), comprising a movable first part (7), which accompanies the rotational motion of the pedal (2), a stationary second part (9), wherein the first and the second part (7, 9) are arranged radially outside of the axis of rotation (A1) of the pedal, a magnetic field sensing component (11) arranged in the first (7) or in the second part (9) and a magnetic element (10) arranged in that part of the first or the second part (7, 9) that does not comprise the magnetic field sensing component (11), wherein the magnetic field sensing component (11) generates an electric signal originating from magnetic interaction between the first and the second part (7, 9) when the first and the second pat are moving in relation to each other, wherein the first part (7) is coupled to the second part (9) so that the motion of the first part in controlled in relation to the second part, wherein the first and the second part (7, 9) are coupled in such a way that the first part (7) comprises a base part (7a) and at least one arm (7b) protruding from the base part (7a) and are arranged such that said at least one arm (7b) at least partly surrounds the second part (9).