Linear Sensor Pin Guidance Using Graphite Plastic
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Solution Overview
Problem
Existing linear sensors in motor vehicle technology are sensitive to vibrations, prone to wear, and have high manufacturing costs, making them unsuitable for precise measurements during engine operation.
Innovation Solution
A linear sensor design featuring a sleeve with a constriction and a pin thickening for precise guidance, with a magnetic field sensor attached to the sleeve, allowing for low-friction, low-wear operation and stable measurements under vibrations, using graphite particle-containing plastics for reduced friction and thermal expansion matching, and a rounded pin end for reduced tilting risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional linear sensor design is used, then manufacturing costs are reduced, but measurement precision deteriorates under vibrations
Solution Approach 1:
The patent changes the physical state and material parameters of the pin by incorporating graphite particles into the plastic material. This parameter change reduces friction and allows the pin to rotate freely, making the measurement system insensitive to vibrations while maintaining high measurement precision
Solution Approach 2:
The patent introduces rotational freedom for the pin within the sleeve, transforming the system from a static guidance mechanism to a dynamic one. The pin can rotate about its longitudinal axis, allowing it to adapt to vibrational forces while maintaining accurate linear position measurement
2Reliability
If a conventional linear sensor design is used, then manufacturing costs are reduced, but device reliability deteriorates due to wear
Solution Approach 1:
The patent uses composite materials by incorporating graphite particles into the plastic material of the pin. This composite structure provides self-lubrication properties that reduce wear and improve reliability, while still being manufacturable through standard injection molding processes
Solution Approach 2:
The graphite particles in the pin material provide self-lubrication during operation. As the pin moves and rotates within the sleeve, graphite particles are released to reduce friction and wear, allowing the sensor to maintain high reliability without external lubrication or maintenance
3Duration of action of moving object
If a conventional linear sensor design is used, then manufacturing costs are reduced, but friction forces increase causing wear
Solution Approach 1:
The patent changes the material parameters of the pin by adding graphite particles to the plastic, fundamentally altering the friction characteristics. This parameter change reduces friction forces between the pin and sleeve, enabling long-term operation with minimal wear
Solution Approach 2:
The graphite-containing plastic material provides self-lubrication during operation. The graphite particles are released gradually as the pin moves, creating a lubricating film that reduces friction and wear, thereby extending the service life of the sensor without requiring external maintenance
4Measurement precision
If the pin is fixed in the sleeve, then manufacturing complexity is reduced, but measurement precision deteriorates due to transverse movements
Solution Approach 1:
The patent replaces fixed mechanical guidance with a dynamic rotational freedom concept. The pin can rotate about its longitudinal axis within the sleeve, allowing it to naturally compensate for misalignments and transverse forces without requiring complex guidance structures, thereby maintaining high measurement precision
Solution Approach 2:
The patent changes the friction parameter by using graphite-containing plastic, which reduces the friction coefficient between the pin and sleeve. This parameter change allows the pin to rotate freely and eliminates transverse movements, achieving high measurement precision without complex guidance mechanisms
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 design ensures precise and stable measurements with low friction and wear resistance, maintaining accuracy and long-term reliability even under engine vibrations and varying temperatures.
Implementation Method 1
a magnetic field sensor that is attached to the sleeve for detecting a displacement of the permanent magnet
Implementation Method 2
the pin of the linear sensor is pressed against a movable measurement object, such as a control member, by a spring force
Implementation Method 3
the pin and/or the sleeve are made of a graphite particle-containing plastic. In this way, abrasion, which is inevitable during operation, ensures a continuous supply of lubricant due to the release of graphite particles
Data Source
AI summary
A linear sensor is described with a casing (5), with a pin (7) which contains a permanent magnet (1) and which is mounted in the casing (5) in a linearly displaceable manner against the force of a spring (6), and with a magnetic field sensor (3) attached to said casing (5) for detecting of a displacement of the permanent magnet (1). The invention provides that the pin (7) is controlled by a first cylindrical guide (8) and a second cylindrical guide (8).