Wheel Hub Bearing Encoder Relocation for Resolution
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Solution Overview
Problem
Current wheel hub bearing systems face limitations in reading resolution due to the density of inverse polarity poles pairs on encoders, which is inadequate for advanced vehicle control systems like autonomous driving, requiring improved rotational speed detection accuracy.
Innovation Solution
The encoder is mounted on the outer periphery of the wheel hub flange, increasing the nominal reading diameter and accommodating more poles pairs, with an adjustable air gap between the sensor and encoder for enhanced resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the encoder is mounted on the inner ring of the bearing, then the device complexity is reduced, but the reading resolution is insufficient for advanced vehicle control systems
Solution Approach 1:
The encoder is relocated from the inner ring (first dimension) to the outer periphery of the flange (second dimension), increasing the nominal reading diameter. This dimensional change allows accommodation of more poles pairs and achieves higher reading resolution without significantly increasing device complexity
Solution Approach 2:
The nominal reading diameter parameter is increased by changing the mounting location of the encoder. This parameter change enables the system to accommodate a greater number of poles pairs, thereby improving reading resolution for autonomous driving applications
2Reliability
If the distance between the encoder and sensor is increased to ensure signal reading, then the measurement reliability is improved, but the manufacturing precision requirements for suspension are increased
Solution Approach 1:
By moving the encoder to the outer periphery of the flange, the system creates a larger nominal reading diameter. This allows the sensor to be positioned at an optimal distance for reliable signal reading while maintaining standard suspension manufacturing tolerances, as the increased radius provides better signal strength at greater distances
3Measurement precision
If the density of poles pairs on the encoder is increased, then the reading resolution is improved, but the manufacturing precision of the encoder is increased
Solution Approach 1:
Instead of increasing pole density on a small encoder, the system increases the nominal reading diameter by relocating the encoder to the flange periphery. This allows use of a lower pole density while achieving the same or better reading resolution, thereby reducing encoder manufacturing precision requirements
Solution Approach 2:
The system changes the nominal reading diameter parameter rather than the pole density parameter. This parameter substitution allows achieving high reading resolution with fewer poles, reducing the manufacturing precision burden on the encoder while meeting autonomous driving control requirements
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 configuration significantly improves rotational speed measurement resolution and accuracy, enabling precise vehicle positioning and control, especially during assisted parking maneuvers.
Implementation Method 1
The sensors normally used are based on magnetic effects, they are positioned outside the bearings, most of the times inside a hole made in the suspension, and are facing the bearing.
Data Source
AI summary
A wheel hub bearing for motor vehicles including a rotatable hub provided with a flange for the engagement of the hub to a wheel of a vehicle and provided with a radially outer free portion and a bearing unit provided with a radially outer ring for the engagement of the wheel hub bearing to a knuckle of the vehicle and a radially inner rotatable ring angularly connected to the hub. Furthermore, the wheel hub bearing has a device for detecting a vehicle parameter and provided with an encoder and a sensor in communication with the encoder. The encoder is ridgidly coupled to the radially outer free portion of the flange to jointly rotate with the hub.