Wheel Speed Detection Device Dual Magnetic Targets
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional wheel speed sensors have limitations in increasing the number of magnetic pole pairs, which restricts the accuracy of wheel rotation speed and direction measurement, hindering advanced vehicle control functions like autonomous driving and automatic parking.
Innovation Solution
A wheel speed detection device with a first target concentrically coupled to the rotating shaft and a second target on the inner ring, both covered by a cap with sensors to detect magnetic field variations, allowing for accurate rotation angle and speed measurement without the need for direct coupling to the shaft and reducing assembly complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of magnetic pole pairs is increased to improve measurement accuracy, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent divides the measurement function into two separate targets: a first target with a small number of magnetic pole pairs for basic rotation detection, and a second target with a large number of magnetic pole pairs for high-precision measurement. This segmentation allows each target to be optimized for its specific function, achieving high measurement accuracy without requiring a single complex target with excessive pole pairs.
Solution Approach 2:
The patent transitions from a single-dimensional measurement approach (one target) to a two-dimensional approach (two targets with different pole pair counts). The first target provides coarse rotation information while the second target provides fine precision information, combining both dimensions to achieve high accuracy without the complexity of a single high-pole-pair target.
2Device complexity
If a single sensor is used to detect both targets, then the device complexity is reduced, but the measurement precision may be compromised
Solution Approach 1:
The patent designs a universal sensor capable of detecting magnetic field variations from both the first target and the second target. This multi-functional sensor integrates the detection capabilities needed for both coarse and fine rotation measurements, reducing the total sensor count while maintaining the precision benefits of having two targets with different pole pair configurations.
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
Enables accurate wheel control with multiple resolution options, simplifies assembly, reduces manufacturing costs, and prevents foreign material ingress, while eliminating the need for separate sensors, thus enhancing measurement accuracy and reliability.
Implementation Method 1
a first sensor disposed in the cap and configured to detect a variation in magnetic field of the first target due to a rotation of the rotating shaft
Implementation Method 2
a second sensor disposed in the cap and configured to detect a variation in magnetic pole of the second target due to a rotation of the inner ring
Data Source
AI summary
A wheel speed detection device according to one aspect of the present disclosure is installable on a wheel bearing which comprises an outer ring and an inner ring coupled to a rotating shaft and relatively rotated relative to the outer ring about the rotating shaft. The wheel speed detection device comprises a first target concentrically coupled to the rotating shaft, a second target disposed along an outer circumference of the inner ring, a cap coupled to the outer ring to cover the first target and the second target, a first sensor disposed in the cap and configured to detect a variation in magnetic field of the first target due to a rotation of the rotating shaft, and a second sensor disposed in the cap and configured to detect a variation in magnetic pole of the second target due to a rotation of the inner ring.