Plastic Encoder Wheel Mounting for Stronger Hub Speed Signals
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Solution Overview
Problem
Existing encoder wheels for wheel hub assemblies face issues with low magnetic characteristics due to ferromagnetic material resistance within rubber materials, and adhesive bonding leads to tensile stress, reducing signal quality and duration.
Innovation Solution
An encoder wheel with a base structure made of plastic material and ferromagnetic powder, magnetized with alternating polarities, is angularly fixed to the outer ring using mechanical supporting and locking means, allowing for secure assembly and improved magnetic field diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base structure is made of rubber material with embedded ferromagnetic powder, then the encoder wheel can be magnetized during vulcanization, but the magnetic characteristics are not very high due to resistance to movement of ferromagnetic material within the rubber material
Solution Approach 1:
The patent uses a composite material consisting of plastic base structure with embedded ferromagnetic powder particles. This composite structure allows the ferromagnetic material to be firmly held within the plastic matrix, preventing movement while maintaining good magnetic characteristics. The plastic material serves as a stable matrix that does not resist the magnetization process like rubber does.
2Ease of manufacture
If the base structure is deformed elastically to fit on the metal support, then the encoder wheel can be fitted after magnetization, but adhesive bonding is required which subjects the encoder wheel to tensile stress, reducing signal quality and duration
Solution Approach 1:
The patent changes the material parameter from elastic rubber to plastic with controlled elasticity. The plastic material has sufficient elasticity to allow deformation during mounting but with controlled recovery that does not require adhesive bonding. This parameter change eliminates the tensile stress problem while maintaining the ability to fit the encoder wheel onto the metal support after magnetization.
Solution Approach 2:
The patent extracts the adhesive bonding step from the assembly process by using plastic material with sufficient elastic recovery. The encoder wheel can be fitted directly onto the metal support through elastic deformation and subsequent recovery, eliminating the need for adhesive bonding that causes tensile stress and degrades signal quality.
3Stability of the object's composition
If adhesive bonding is used to fix the encoder wheel to the metal support, then angular fixation is achieved, but tensile stress from elastic stress and adhesive bonding reduces the quality and duration of the signal
Solution Approach 1:
The patent changes the material properties of the base structure from highly elastic rubber to plastic with controlled, lower elasticity. This parameter change allows the encoder wheel to maintain angular fixation through controlled elastic recovery without requiring adhesive bonding, thereby eliminating tensile stress and preserving signal quality and duration over time.
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 solution enhances the angular fixation and signal quality by utilizing the plastic material's low elasticity for secure mounting and improved magnetic field diffusion, overcoming the limitations of rubber-based encoder wheels.
Implementation Method 1
The encoder wheel is magnetized by subjecting the ferromagnetic material to a magnetic field so as to orientate the ferromagnetic material along predetermined lines of flux
Implementation Method 2
use may be made of the specific elastic characteristics of rubber materials which allow them to undergo considerable deformation without permanent alteration and/or damage
Data Source
AI summary
A speed measuring device for a wheel hub assembly equipped with a rolling bearing. The measuring device having an encoder wheel mounted on a rotating ring of the bearing, a mechanical support disposed between the encoder wheel and the ring to cause the encoder wheel and the ring to be angularly fixed to one another, and a mechanical lock for axially locking the encoder wheel in a seat formed by the mechanical lock together with the mechanical support. The encoder wheel is equipped with a base structure made of plastic material mounted in a seat.