Angular Position Sensor Anti-Rotation Spring Mechanism
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Solution Overview
Problem
Existing rotation angle sensors in motor vehicles face accuracy issues due to rotational play caused by temperature-dependent plastic spring force loss, leading to measurement inaccuracies and noise during longitudinal movements.
Innovation Solution
A combination of a plastic spring and a metal spring is used to ensure consistent clamping force, with the metal spring reinforcing the plastic spring to maintain anti-rotation and accuracy, while allowing for sliding movement to prevent noise, using a bent leaf metal spring for ease of manufacturing and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plastic spring is used in the connecting component to provide anti-rotation force, then the housing is braced in the groove, but at high temperatures the plastic softens and loses clamping force causing rotational play
Solution Approach 1:
The connecting component combines plastic and metal materials in a composite structure. The plastic housing provides noise-free operation and basic structural function, while the integrated metal spring provides temperature-resistant clamping force. This composite approach allows each material to contribute its superior properties: plastic for quiet operation and metal for thermal stability.
Solution Approach 2:
The invention changes the material parameter of the spring component from plastic to metal, fundamentally altering the temperature-dependent mechanical properties. The metal spring maintains its elastic modulus and clamping force across a wide temperature range, unlike plastic which softens at elevated temperatures. This parameter change ensures reliable anti-rotation performance under all operating conditions.
2Ease of manufacture
If a plastic spring provides clamping force in the groove, then assembly is simple, but the spring force decreases at high temperatures leading to rotational play and measurement inaccuracy
Solution Approach 1:
The connecting component integrates plastic and metal materials where the plastic housing provides simple molding and assembly, while the embedded metal spring ensures measurement precision by maintaining constant clamping force. This composite structure combines the manufacturing advantages of plastic injection molding with the dimensional stability of metal springs.
Solution Approach 2:
The invention applies local quality by using different materials in different regions of the connecting component. The plastic portions provide ease of manufacture and noise-free operation, while the metal spring portion specifically addresses the precision requirement by maintaining stable mechanical properties. Each material is placed where it provides the most benefit.
3Reliability
If the connecting component is braced in the groove to prevent rotation, then anti-rotation is achieved, but longitudinal movement is restricted causing noise
Solution Approach 1:
The invention changes the friction parameter at the contact interface by using plastic material in the connecting component that contacts the groove. Plastic provides lower friction and smoother movement compared to metal-on-metal contact, reducing noise during longitudinal movements while maintaining adequate anti-rotation bracing through the metal spring.
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
This solution provides a play-free anti-rotation mechanism with high accuracy and noise reduction, maintaining sensor precision even at high temperatures and during temperature-induced plastic softening, ensuring reliable angle measurements.
Implementation Method 1
a spring made of the same material as the housing is formed on the connecting component
Implementation Method 2
A plastic spring of the connection member is supported by a metal spring
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to an angular position sensor for determining a relative angular position in relation to a reference position, comprising a housing (1), at least one rotor (3, 4) that is rotatably mounted in the housing (1), and a printed circuit board (2) that has electric and/or electronic components and one or more stators, corresponding to the number of rotors (3, 4). A connecting component (7) prevents the housing (1) from being twisted in a groove of a stationary part of a motor vehicle. The aim is to improve said angular position sensor in such a way as to avoid play under any operating conditions when preventing the housing from being twisted and make it easy to mount the sensor. In order to be able to do so, a plastic spring (13) of the connecting component (7) is supported by a metal spring (14).