Torque Angle Sensor Clearance Elimination via Elastic Intermediaries
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Solution Overview
Problem
The assembly of torque and angle sensors with steering shafts in electronic power steering systems faces issues with circumferential and axial clearances, leading to potential malfunctions and breakage due to impact, increasing manufacturing costs and complexity.
Innovation Solution
A torque angle sensor design featuring an upper case with a central input and output shaft, a rotor, a middle case, and a lower case with fastening mechanisms and elastic components to absorb impacts and eliminate clearances, facilitating assembly and preventing mis-operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a torque angle sensor with unified function is integrated, then device complexity is reduced, but circumferential and axial clearances are generated during assembly
Solution Approach 1:
A positioning pin is introduced as an intermediary element between the sensor housing and the case to eliminate circumferential clearance. The positioning pin fits into corresponding positioning holes, providing a precise mechanical reference that ensures accurate relative positioning without requiring high-precision machining of the housing and case interfaces.
Solution Approach 2:
An elastic member is introduced as an intermediary between the lower case and the spacer cover to eliminate axial clearance. The elastic member is compressed between these two components, providing a preloaded mechanical connection that eliminates gaps and ensures precise axial positioning while accommodating minor dimensional variations.
2Measurement precision
If precision components are used in the torque angle sensor, then measurement precision is improved, but reliability decreases due to sensitivity to impact
Solution Approach 1:
An elastic member is installed between the lower case and the spacer cover to provide beforehand cushioning against axial impacts. This elastic element absorbs impact energy through deformation, protecting the precision components (such as the rotor and sensor elements) from damage while maintaining their positioning accuracy during normal operation.
3Manufacturing precision
If clearance elimination methods are applied, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The positioning pin and elastic member are designed as simple, standardized mechanical elements that are integrated into the existing sensor structure. These intermediaries add minimal structural complexity while effectively eliminating clearances, as they utilize simple geometric shapes (cylindrical pin, compressed elastic element) that are easy to manufacture and assemble.
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 effectively removes clearances and absorbs impacts, preventing breakage and mis-operation of the torque angle sensor components, thus simplifying the assembly of electronic power steering apparatuses and enhancing their reliability.
Implementation Method 1
a lower side of the lower case is assembled with a spacer cover through an elastic member so as to absorb an axial impact
Data Source
AI summary
Disclosed is a torque angle sensor and an electronic power steering apparatus having the torque angle sensor, which includes an upper case, an upper side of which is assembled with a sensor housing, a rotor assembled with an inside of the upper case, the rotor fitted around an outer surface of the output shaft extending through the rotor and assembled with an inside of the upper case, a lower case, a lower side of which is assembled with a spacer cover, and a middle case assembled between the upper case and the lower case. The upper case includes holding parts opposed to each other and formed on an upper surface of the upper case, which is assembled with the sensor housing, and a seating spring protruding downward with inclination from an end of one of the holding parts and elastically bent when the upper case is assembled with the sensor housing. Therefore, it is possible to remove a circumferential clearance and an axial circumferential clearance during assembling of the torque angle sensor with peripheral elements and can absorb movement created by an impact, so as to effectively prevent breakage and mis-operation of the elements included in the torque angle sensor and facilitate the assembling of the electronic power steering apparatus.