Pole Wheel Axial Bulge for Sensor Air Gap Control
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Solution Overview
Problem
Existing pole wheel designs fail to maintain a consistent air gap between the sensor and the pole wheel surface, which can be disrupted by rust penetration and material expansion, affecting the accuracy of rotational speed and angular position measurements.
Innovation Solution
A pole wheel design with uniformly distributed apertures and radial webs features an axially protruding bulge that maintains a predetermined air gap with the rotational speed sensor, minimizing friction losses and accommodating potential displacements due to rust or material changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pole wheel is directly mounted on the brake disk without additional features, then the fastening is simple, but the air gap between the sensor and pole wheel surface cannot be maintained consistently due to rust penetration and material expansion
Solution Approach 1:
The invention introduces an axial dimension feature (the bulge) on the pole wheel surface that protrudes in the axial direction. This axial protrusion compensates for radial displacements caused by rust penetration and material expansion, maintaining the air gap in the radial direction between the sensor and pole wheel surface.
Solution Approach 2:
The invention changes the surface geometry parameter of the pole wheel by adding an axially protruding bulge. This geometric modification allows the pole wheel to accommodate variations in radial position while maintaining a consistent air gap, thereby preserving measurement accuracy despite rust or thermal expansion.
2Measurement precision
If the air gap between sensor and pole wheel is reduced to improve measurement precision, then measurement accuracy improves, but friction losses increase and the system becomes sensitive to rust penetration and material expansion
Solution Approach 1:
By introducing the axial bulge feature, the invention decouples the air gap maintenance from the mounting interface. The sensor can be positioned closer to the pole wheel surface (reducing air gap for better precision) while the axial bulge compensates for any contact or displacement, preventing excessive friction and maintaining measurement reliability.
3Loss of energy
If the pole wheel surface is made flat and smooth to reduce friction, then friction losses decrease, but the ability to accommodate rust penetration and material expansion is reduced
Solution Approach 1:
The invention applies a localized geometric feature (the axially protruding bulge) at specific locations on the pole wheel surface where it interacts with the sensor. This local modification maintains smooth contact surfaces to reduce friction while the bulge itself provides the necessary accommodation for rust penetration and material expansion.
Data Source
AI summary
A pole wheel is provided. The pole wheel can be mounted on a brake disk of a vehicle wheel brake. The pole wheel has apertures which are uniformly distributed over its circumference and which are spaced apart from one another by radial webs. The pole wheel has an axially protruding bulge radially above its apertures and radial webs.