Angular Position Sensor Rotor Locking Mechanism
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Solution Overview
Problem
Existing rotation angle sensors face challenges in achieving precise alignment and cost-effective production, with existing solutions often requiring complex assembly processes and being susceptible to temperature influences and wear.
Innovation Solution
A rotation angle sensor design featuring a rotor locked to the housing with a spring ring and snap-in connections, along with optimized bearing surfaces and lubrication, ensures precise positioning and stability, while minimizing manufacturing tolerances and wear effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rotor is mounted directly on a printed circuit board with a bearing element snapped onto it, then assembly is simplified, but manufacturing tolerances cannot be compensated for and positioning precision deteriorates due to temperature effects and wear
Solution Approach 1:
A plastic connection piece is introduced as an intermediary component between the housing and the rotor bearing arrangement. This mediator absorbs manufacturing tolerances and provides a stable mounting base for the rotor, ensuring precise positioning relative to the stator while maintaining ease of assembly through snap-fit connections.
Solution Approach 2:
The plastic connection piece is designed to change its physical parameters (dimensions, rigidity) with temperature variations. This compensates for thermal expansion and contraction effects, maintaining manufacturing precision across different operating temperatures without requiring complex compensation mechanisms.
2Manufacturing precision
If manufacturing tolerances are minimized and complex housing manufacturing is used, then positioning precision improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The housing structure is segmented into separate functional components: a main housing body, a plastic connection piece, and a bearing element. This segmentation allows each component to be manufactured with standard tolerances using simple processes, while their combined assembly achieves the required positioning precision through the interlocking design of these segments.
3Manufacturing precision
If detent springs are used to latch the rotor, then positioning precision improves, but the preload decreases at high temperatures when plastic becomes softer
Solution Approach 1:
The solution uses a composite approach combining metal detent springs with a specially formulated plastic connection piece. The metal springs provide temperature-stable elastic properties and maintain constant preload, while the plastic component provides the necessary mechanical support and geometric constraints. This material combination resolves the thermal instability issue while maintaining positioning 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 solution provides a highly accurate and durable rotation angle sensor with consistent friction and noise-free operation across various conditions, maintaining precision even at high temperatures.
Implementation Method 1
a spring ring being arranged on detent arms under preload
Implementation Method 2
the bearing surfaces are lubricated. Alternatively or additionally, the housing and/or parts of the first rotor are made of a plastic with embedded lubricant
Data Source
Figure 1
Figure 2
Figure 3~4
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). The aim is to improve said angular position sensor in such a way that a first of the rotors (3) can be oriented particularly accurately in relation to the stator and the sensor is inexpensive to produce. In order to be able to do so, a first of the rotors (3) is interlocked with the housing (1) without play, a spring washer (14) that biases locking arms (11) being provided.