Magnetized Gear Wheel for Homogeneous Angle Sensor Field
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Solution Overview
Problem
Conventional angle sensors for determining the angle of rotation of a rotatable body, such as a steering column in a vehicle, require complex production processes involving separate magnetic pills and multiple molding steps, which increase production expenditure and can lead to inaccuracies in measuring the magnetic field orientation.
Innovation Solution
A toothed wheel entirely made from a magnetizable material, specifically designed to be magnetized with higher magnetization in the central region than the edge region, allowing for a homogeneous magnetic field generation that can be accurately measured by a magnetic field sensor, thus simplifying production and improving measurement precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate magnetic pills are used in conventional angle sensors, then the magnetic field can be generated, but the production process becomes complex with multiple molding steps and increased production expenditure
Solution Approach 1:
The patent combines the magnetic pill and toothed wheel into a single integrated component made entirely from magnetizable material. This merging eliminates the need for separate magnetic pills and multiple molding steps, directly resolving the technical contradiction by simplifying the production process while maintaining the magnetic field generation function.
Solution Approach 2:
The integrated toothed wheel serves multiple functions simultaneously: it provides the mechanical toothed structure for gear engagement and generates the magnetic field through its magnetizable material composition. This multi-functionality eliminates the need for separate magnetic pills, resolving the contradiction between manufacturing simplicity and structural complexity.
2Measurement precision
If uniform magnetization is applied across the entire toothed wheel, then the magnetic field is generated, but measurement accuracy decreases due to disturbances from tooth magnetization
Solution Approach 1:
The patent applies different magnetization levels to different regions of the toothed wheel: the central region is magnetized to a greater extent than the edge region containing the teeth. This local quality differentiation reduces magnetic field disturbances from the teeth while maintaining sufficient field strength for accurate measurement in the central region, directly resolving the measurement accuracy contradiction.
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 approach simplifies the production of angle sensors by eliminating the need for separate magnetic pills and enhances measurement accuracy by ensuring a strong, homogeneous magnetic field in the central region, reducing disturbances from tooth magnetization and improving the precision of angle determination.
Implementation Method 1
The toothed wheel is embodied in accordance with the disclosure completely from a magnetizable material, wherein the toothed wheel is magnetized to a greater extent in a central region of the toothed wheel than in an edge region in which the teeth are arranged
Implementation Method 2
The orientation of the magnetic field that is generated by the magnetic pill can be measured with the aid of a magnetic field sensor that is arranged adjacent to an end face of the measuring toothed wheel
Data Source
AI summary
An angle sensor for determining a rotation angle of a rotatable body, such as a steering column in a motor vehicle, includes a gear wheel. The orientation of a magnetic field generated by the gearwheel is configured to be detected by a magnetic field sensor. The gear wheel is comprised of a magnetisable material, such as hard ferrite, into which a magnetization is introduced. The gear wheel is stronger in a central region than in an edge region in which the teeth are arranged. In order to weakly magnetize the edge region, which minimizes a negative influence of the teeth on the homogeneity of the generated magnetic field, the front face of the gear wheel is configured to be magnetized. The magnetization process advantageously takes place at the same time as an injection moulding process to form the gearwheel. A method is implemented to produce the gear wheel.