Position Sensor PA Encapsulation for Transmission Reliability
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Solution Overview
Problem
Position sensors in automatic transmissions face challenges in withstanding extreme temperatures, aggressive transmission oil, high mechanical loads, and metallic abrasion, which existing designs struggle to address effectively, leading to potential short circuits and increased component count and manufacturing costs.
Innovation Solution
The use of PA overmolding as both a seal and loss protection for the magnetic slide, combined with a PPS guide housing, reduces component count and manufacturing costs by integrating the latching hook into the PA encapsulation, ensuring electrical insulation and preventing short circuits from metallic particles, while minimizing the air gap between the sensor package and magnet slide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate loss protection component is used for the magnetic slide, then the magnetic component is protected against loss, but the number of components and manufacturing complexity increase
Solution Approach 1:
The patent integrates the loss protection function directly into the PA encapsulation by forming a latching hook as an integral part of the encapsulation structure. This merging of functions eliminates the need for a separate loss protection component while maintaining the protective function for the magnetic slide.
Solution Approach 2:
The PA encapsulation serves multiple functions simultaneously: it acts as a seal against transmission oil, provides electrical insulation, and incorporates a latching hook for loss protection. This multi-functionality reduces the overall component count while maintaining all necessary protective and functional characteristics.
2Reliability
If multiple separate components are used for sealing and loss protection, then protection functions are ensured, but manufacturing time and costs increase
Solution Approach 1:
The patent combines sealing, electrical insulation, and loss protection functions into a single PA encapsulation component manufactured in one injection molding process. This integration significantly reduces manufacturing time by eliminating the need for separate assembly steps for multiple protective components.
Solution Approach 2:
The latching hook is formed as an integral part of the PA encapsulation during the injection molding process itself, rather than being added as a separate component afterward. This preliminary formation of the securing element streamlines manufacturing and reduces assembly time.
3Object-affected harmful factors
If traditional sealing methods are used, then protection against transmission oil is provided, but electrical insulation and short circuit prevention are not sufficiently ensured
Solution Approach 1:
The PA encapsulation is designed to simultaneously provide chemical resistance to transmission oil and electrical insulation properties. The material selection and structural design ensure that the same component that seals against the aggressive ATF medium also prevents electrical short circuits caused by metallic particles in the fluid.
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 enhances the durability and reliability of position sensors by preventing short circuits and reducing manufacturing complexity, ensuring the sensors function accurately across varying temperatures and mechanical stresses, while minimizing the risk of component failure and production costs.
Implementation Method 1
the PA encapsulation therefore serves both as a seal for the sensor package against the transmission oil
Implementation Method 2
the hook-shaped projection of the securing device protrudes into the plane of movement of the magnetic or magnetized component and delimits its lateral travel path
Implementation Method 3
the PA encapsulation ensures electrical insulation from one another, which in particular excludes short circuits due to contamination in the surrounding medium
Implementation Method 4
four digital Hall switches are used, which are arranged on a circuit board in such a way that they detect the magnetic coding of a linearly displaceable multipolar permanent magnet
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a position sensor (10) comprising a housing, in particular a guide housing (14) comprising at least one guide rail (36, 38) for a magnetic component (34). An encapsulation (48) that electrically insulates and/or fixes a lead frame assembly (50) and/or a conductor assembly (40) is provided on the guide housing (14). Said encapsulation forms a retainer (42, 44) for the magnetic component (34).