Insulated Speed Sensor Housing for High-Temperature Accuracy
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Solution Overview
Problem
Active speed sensors used in vehicle assistance systems often experience overheating due to thermal energy transfer from the environment or moving objects, leading to incorrect measurements or failure.
Innovation Solution
A speed sensor design featuring a cup-shaped housing with evacuated outer chambers that thermally insulate the Hall element and semiconductor chip, reducing heat transfer through conduction, radiation, and convection, and a ferromagnetically conductive coupling element to enhance signal strength and reduce heat load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the speed sensor is installed near a brake disc or other heat-generating components, then the sensor can detect speed in high-temperature environments, but the sensor element overheats causing inaccurate measurements or failure
Solution Approach 1:
The housing is divided into functionally distinct regions: a front region exposed to high temperatures and a rear region housing the sensitive electronics. The thermal insulation barrier creates a clear segmentation between the hot environment and the protected sensor element, allowing the sensor to operate in high-temperature environments without compromising measurement accuracy.
Solution Approach 2:
A thermal insulation barrier (intermediary structure) is introduced between the rotating object and the sensor element. This intermediary component blocks heat transfer while allowing magnetic field penetration, enabling the sensor to maintain accurate measurements even when installed near heat-generating components like brake discs.
2Reliability
If thermal insulation measures are added to protect the sensor element, then measurement accuracy is maintained, but device complexity increases
Solution Approach 1:
The housing serves multiple functions simultaneously: it provides mechanical protection for the sensor element, creates structural support, and acts as a thermal insulation barrier. By integrating these functions into a single component rather than adding separate insulation elements, the design maintains measurement accuracy while minimizing increases in device complexity.
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 significantly increases the functional reliability of speed sensors by minimizing heat transfer and maintaining accurate measurements, even in high-temperature environments.
Implementation Method 1
an empty outer chamber is formed between a boundary surface of an outer recess and an inner surface of a wall of the speed sensor housing... The speed sensor element is particularly effectively thermally insulated from the rotating object by this empty outer chamber at the front
Implementation Method 2
reducing heat transfer through conduction, radiation, and convection
Implementation Method 3
reducing heat transfer through conduction, radiation, and convection
Implementation Method 4
the speed sensor element comprises a Hall element and a semiconductor chip for sensing changes in a magnetic field
Data Source
Figure 1A
Figure 1B~1C
Figure 2
AI summary
The invention relates to a speed sensor (100) for measuring the speed of an object moving relative to the speed sensor (100), comprising a speed sensor housing (111) which is provided for sliding and/or frictional and/or integral insertion into a fixed receptacle, wherein the speed sensor housing (111) houses an injection moulded plastic part (107), into which at least one portion of a speed sensor element (104, 105) has been injected. The invention provides that • a) the injection moulded part (107) has at least one outer recess (116) on its outer peripheral face (113) pointing towards an inner face (112) of a wall of the speed sensor housing (111), wherein an empty outer chamber is formed between each boundary surface of an outer recess (116) and the inner surface (112) of the wall of the speed sensor housing (111), and/or that • b) at least one inner recess (119), which forms an empty inner chamber, is formed inside the injection moulded part (107). The chambers, which are filled with air or are partially or fully evacuated, are intended to impede the transfer of heat from the housing to the injection moulded part or the transport of heat inside the injection moulded part.