Torque Sensor Magnet Buffer and Shield Ring Integration
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Solution Overview
Problem
Conventional contactless torque sensors for electric power steering systems have complex assembly processes, high manufacturing costs, and durability issues due to the large number of constituent elements, leading to increased error possibilities and reduced sensitivity.
Innovation Solution
A torque sensor device with a simplified structure, incorporating a magnet unit with a magnet ring and holder, a collector unit for focusing the magnetic field, and a shield ring unit to change the magnetic field, utilizing a silicon coating layer or felt paper as a magnet buffer to prevent damage from external forces and thermal expansion differences, and featuring a self-assembly design with ultrasonic fusion and snap-fit configurations for improved durability and assembly efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional contactless torque sensor uses multiple constituent elements (magnet unit, collector unit, shield ring unit), then the torque detection function is achieved, but the assembly process becomes complicated and manufacturing cost increases
Solution Approach 1:
The patent combines the magnet unit, collector unit, and shield ring unit into a single integrated housing structure. The housing simultaneously accommodates all three functional units, eliminating the need for separate assemblies and reducing the number of assembly steps while maintaining the torque detection function
Solution Approach 2:
The housing serves multiple functions: it acts as the structural enclosure, the magnet unit generates the magnetic field for detection, the collector unit focuses the magnetic flux, and the shield ring unit protects against external magnetic interference. This multi-functionality reduces the overall system complexity
2Reliability
If a conventional contactless torque sensor uses multiple constituent elements, then the torque detection function is achieved, but the manufacturing cost increases
Solution Approach 1:
By integrating multiple functional units into a single housing, the patent reduces the number of separate manufacturing processes and assembly operations, thereby lowering manufacturing costs while maintaining detection reliability
Solution Approach 2:
The patent extracts the essential functional requirements (magnetic field generation, flux collection, and shielding) and implements them through a simplified integrated structure, removing unnecessary complexity and reducing manufacturing overhead
3Reliability
If a conventional contactless torque sensor uses multiple constituent elements, then the torque detection function is achieved, but the durability is reduced due to excessive elements
Solution Approach 1:
The integration of functional units into a single housing reduces the number of interfaces and connection points, which are typically weak points for failure. This reduces the overall error possibilities and improves durability while maintaining the torque detection function
Solution Approach 2:
The patent converts the potential harm of multiple separate elements (which increase assembly errors and reduce durability) into a benefit by integrating them, thereby reducing the number of potential failure points and improving long-term reliability
4Device complexity
If the magnet ring is directly connected to the magnet cover and holder, then the structure is simple, but damage occurs due to external forces and thermal expansion differences
Solution Approach 1:
The patent introduces a magnet buffer between the magnet ring and the magnet cover/holder to provide cushioning against external forces and thermal expansion differences before damage can occur. This buffer absorbs mechanical stress and prevents direct contact between the magnet ring and the rigid housing structures
5Ease of manufacture
If a simplified structure with fewer elements is used, then manufacturing cost is reduced, but the sensitivity and detection reliability may be compromised
Solution Approach 1:
The patent concentrates the magnetic field generation and detection functions in specific localized areas within the housing. The magnet unit is positioned to create a focused magnetic field, and the collector unit is strategically placed to maximize flux collection, thereby maintaining high detection sensitivity despite the simplified overall structure
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 sensitivity and reliability of torque detection, reduces manufacturing costs, and improves durability by preventing damage from external forces and thermal expansion, while simplifying the assembly process and reducing the risk of erroneous assembly through a stable and self-aligning structure.
Implementation Method 1
a magnet unit accommodated in the housing and including a magnet ring connected to one end of one of the input shaft and the output shaft
Implementation Method 2
a collector unit fixed in position to the housing in such a manner as to be disposed at the outside of the magnet unit, and configured to focus a magnetic field generated from the magnet unit
Implementation Method 3
a sensing unit including a torque sensor disposed at the outer circumference of the collector unit and configured to detect the magnetic field focused by the collector unit
Implementation Method 4
a shield ring unit interposed between the collector unit and the magnet unit in such a manner as to be connected to one end of the other of the input shaft and the output shaft, and configured to change the magnetic field from the magnet unit, which is focused by the collector unit, by means of the relative rotation between the input shaft and the output shaft
Data Source
AI summary
A torque sensor device disposed between an input shaft and an output shaft. The torque sensor device includes a housing, a magnet unit accommodated in the housing and including a magnet ring, a collector unit fixed in position to the housing, a sensing unit including a torque sensor disposed at the outer circumference of the collector unit, and a shield ring unit interposed between the collector unit and the magnet unit. The magnet unit includes: a magnet holder connected to the input shaft; a pair of magnet rings spaced apart from each other with the magnet holder interposed therebetween; a magnet cover formed in such a manner that the magnet ring is disposed between the magnet cover and the magnet holder so as to be connected to the magnet holder; and a magnet buffer disposed between the magnet cover and the magnet ring.