Vehicle Actuation Unit Assembly With Elastic Inductive Target
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Solution Overview
Problem
Existing vehicle door handle actuation units with inductive sensors face challenges during assembly, as precise alignment of the metallic target with the inductive sensor is critical for sensitivity and reliability, but deviations can occur due to manufacturing or assembly tolerances.
Innovation Solution
The solution involves providing support means on the printed circuit board and/or the housing for the metallic target, which is designed to be elastic. This ensures that the target is compressed between the housing and its support means, maintaining reliable contact and alignment with the inductive sensor, even in the presence of assembly deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the target is attached to the housing before assembly, then the alignment can be adjusted during assembly, but the alignment precision deteriorates due to assembly tolerances and lack of pre-alignment
Solution Approach 1:
The target is pre-aligned with the inductive sensor on the printed circuit board before the housing is assembled. The target is attached to the housing part that will be connected to the printed circuit board, ensuring that when the housing parts are joined, the target is already in the correct position relative to the sensor, eliminating the need for post-assembly adjustment and compensating for assembly tolerances.
Solution Approach 2:
The target is nested within the housing structure in such a way that it is pre-positioned relative to the inductive sensor. The housing parts are designed to hold the target and sensor in a fixed spatial relationship, with the target being accommodated in a recess or mounting structure that ensures proper alignment when the housing is assembled.
2Manufacturing precision
If the target is attached to the housing after assembly, then the alignment precision can be maintained, but the assembly complexity increases due to additional positioning steps
Solution Approach 1:
The attachment of the target to the housing is merged with the housing assembly process itself. The target is attached to one housing part in a way that integrates with the connection to the other housing part containing the sensor, so that a single assembly operation achieves both housing assembly and target positioning, reducing the number of separate steps required.
Solution Approach 2:
The housing structure serves multiple functions: it provides mechanical protection, defines the spatial relationship between components, and incorporates the target mounting structure. The printed circuit board serves both as the sensor mounting platform and as part of the housing assembly, reducing the need for separate positioning mechanisms.
3Manufacturing precision
If the target is positioned far from the inductive sensor, then assembly tolerances are more forgiving, but the sensor sensitivity deteriorates
Solution Approach 1:
The physical parameters of the target are modified to enhance its detectability by the inductive sensor. The target is made from conductive material with optimized geometry and electrical properties to increase its interaction with the sensor's electromagnetic field, allowing for stronger signal detection even at the minimal required distance, thus maintaining sensitivity while accommodating assembly tolerances.
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 elastic target design ensures consistent and reliable detection of housing deformations caused by applied forces, as it maintains precise alignment with the inductive sensor and compensates for small assembly tolerances, thereby enhancing the reproducibility and accuracy of the actuation unit.
Implementation Method 1
They are characterized by high reliability. They are used both for recording technical processes in the vehicle (e.g. ABS) and for recording interactions with the user. Inductive sensors work according to the principle of the change in impedance of a conductive coil, which is caused by eddy currents in a conductive target sensed by the sensor.
Implementation Method 2
The sensor can be excited by an oscillator, for example, which generates an electromagnetic field that interacts with the nearby (galvanically decoupled) target.
Implementation Method 3
The solution involves providing support means on the printed circuit board and/or the housing for the metallic target, which is designed to be elastic. This ensures that the target is compressed between the housing and its support means, maintaining reliable contact and alignment with the inductive sensor, even in the presence of assembly deviations.
Data Source
Figure 1a~1c
Figure 1d~2
Figure 3a~5
AI summary
An actuator unit comprising a housing (11a, 11b), with a printed circuit board (2), wherein the printed circuit board (2) is mounted in the housing (11a, 11b) and comprises an inductive sensor (3a, 3b). A metallic target (4a, 4b) is associated with the inductive sensor, wherein the target (4a, 4b) extends in sections between the inductive sensor (3a, 3b) and the housing (11a, 11b). The target (4a, 4b) is associated with support means (5a) on the circuit board (2) or the housing and rests on the support means (5a) and/or is attached to the support means, and wherein the target (4a, 4b) is elastic at least in sections. The target (4a, 4b) abuts the housing (11a, 11b) in a section extending over the inductive sensor (3a, 3b) and is in a compressed state between the housing (11a, 11b) and the support means (5a) within the elasticity range of the target (4a, 4b).