Multi-Directional Force Sensor Structure for Compact Capacitive Sensing
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Solution Overview
Problem
Existing multidirectional force sensors are rigid and have high manufacturing costs due to complex metal housing designs, and they require significant space, making them unsuitable for applications like seat adjustment switches in motor vehicles.
Innovation Solution
A compact, cost-effective multidirectional force sensor with a metallic sensor element made entirely of metal, featuring a sensor pin and plate connected via strip-shaped support elements cut from a single metal plate, allowing for pivoting movement and capacitive measurement of actuation forces across multiple directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal housing is used for the sensor element, then rigidity and durability are improved, but manufacturing complexity and cost increase due to difficult demolding
Solution Approach 1:
The sensor element is divided into separate components: a plastic housing and a metal sensor pin, where only the critical force-sensing part is metal. This segmentation allows the housing to be easily molded while maintaining metal rigidity where needed, resolving the contradiction between rigidity and manufacturing ease.
Solution Approach 2:
The sensor pin and sensor plate are integrally connected through strip-shaped support elements cut from a single metal plate, creating a unified metal sensing structure. This merging provides rigidity and durability while the simple cut-out construction keeps manufacturing straightforward.
2Reliability
If a metal housing with complex structure is used, then durability is improved, but space requirements increase
Solution Approach 1:
By segmenting the sensor element into a compact plastic housing and a minimal metal sensor pin assembly, the overall volume is reduced. The plastic housing provides sufficient protection while the metal components are minimized to only where mechanically necessary, reducing total space while maintaining durability.
Solution Approach 2:
The plastic housing acts as a flexible protective shell that provides durability without the bulk of a full metal housing. This thin-walled plastic structure protects the internal metal sensing components while occupying minimal space.
3Strength
If the sensor element is made entirely of metal, then rigidity is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The sensor element uses a plastic housing for the non-critical structural parts and metal only for the sensor pin and support elements that require rigidity. This selective material usage maintains necessary rigidity while dramatically reducing manufacturing cost compared to a fully metal construction.
Solution Approach 2:
The material composition parameter is changed from 100% metal to a hybrid plastic-metal construction. This parameter change optimizes the cost-to-rigidity ratio by using metal only where mechanically necessary and plastic where flexibility and cost-effectiveness are prioritized.
4Volume of moving object
If a compact design is implemented, then space requirements are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The compact design is achieved through segmentation into standardized components with simple geometries. The plastic housing and metal sensor pin are separate, easily manufactured parts that assemble together, avoiding the need for high-precision complex metal forming while maintaining compact overall dimensions.
Solution Approach 2:
The plastic housing provides a compact enclosure with tolerances that are easier to achieve than precision metal casting or forming. The plastic material allows for simpler molding processes that maintain compact dimensions without requiring extreme manufacturing 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 simple, inexpensive, and compact force sensor with enhanced rigidity and reduced manufacturing complexity, enabling precise force detection across multiple actuation directions while minimizing space requirements.
Implementation Method 1
capacitance values of capacitors formed by the arrangement of the sensor plate and the conductive surfaces change with the swiveling motion of the sensor pin
Data Source
AI summary
An electrical multidirectional force sensor includes a sensor element having a sensor pin and a sensor plate and a circuit board. The sensor pin is movable in at least two actuation directions. The sensor plate is integrally connected to multiple strip-shaped support elements. Each strip-shaped support element has an end portion with an opening. The sensor plate and the strip-shaped support elements are cut free in one piece from a metal plate. The sensor plate is connected to the sensor pin to move relative to the circuit board in correspondence with movement of the sensor pin.