Torque Sensor Shield Ring Insert-Molding
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Solution Overview
Problem
Conventional contactless torque sensors for electric power steering systems have complex structures, leading to increased manufacturing costs, assembly errors, and reduced durability due to the large number of constituent elements.
Innovation Solution
A torque sensor device with a simplified structure, incorporating a magnet unit, a collector unit, a sensing unit, and a shield ring unit, which includes a shield ring body and shield ring pieces, to detect torque between input and output shafts through relative rotation, with the shield ring pieces being insert-molded and over-molded for stability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional contactless torque sensor is used, then torque detection function is achieved, but the structure becomes complex with excessive constituent elements
Solution Approach 1:
The patent combines multiple functional components into an integrated structure. The housing integrates support functions for the magnet unit, collector unit, and shield ring unit. The shield ring unit combines the shield ring body with multiple shield ring pieces that are insert-molded and over-molded together, reducing the number of separate components while maintaining the torque detection function through magnetic field interactions between the permanent magnet and detection ring.
Solution Approach 2:
The housing serves multiple functions: it supports the magnet unit, collector unit, and shield ring unit, and provides structural enclosure. The shield ring pieces simultaneously provide magnetic shielding and structural support. This multi-functionality reduces the need for separate dedicated components, simplifying the overall structure while maintaining reliability.
2Reliability
If a conventional contactless torque sensor with many constituent elements is used, then torque detection is achieved, but manufacturing cost increases
Solution Approach 1:
The shield ring pieces are insert-molded into the shield ring body and then over-molded to form an integrated assembly. This merging of multiple pieces into a single molded structure reduces manufacturing steps, eliminates the need for separate assembly operations, and reduces overall manufacturing cost while maintaining the functional integrity of the torque detection system.
Solution Approach 2:
The shield ring pieces are prepared and positioned in advance within the shield ring body through insert-molding before the over-molding process. This preliminary action ensures proper positioning and reduces assembly complexity, leading to lower manufacturing costs while maintaining the detection function.
3Reliability
If a conventional contactless torque sensor with excessive constituent elements is used, then torque detection is achieved, but assembly errors increase
Solution Approach 1:
The shield ring pieces are combined with the shield ring body through insert-molding and over-molding processes, creating a pre-assembled integrated unit. This merging eliminates multiple separate assembly steps, reduces the opportunity for assembly errors, and improves manufacturing precision while maintaining the torque detection function through the integrated magnetic shielding and structural support.
4Reliability
If a conventional contactless torque sensor with many constituent elements is used, then torque detection function is achieved, but durability is reduced
Solution Approach 1:
The shield ring pieces are permanently integrated with the shield ring body through insert-molding and over-molding, creating a robust, unified structure that eliminates interfaces between separate components. This merging reduces potential failure points from assembly interfaces, improves structural integrity, and enhances durability while maintaining the torque detection function through the integrated magnetic field shielding and support 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 reduces manufacturing costs, minimizes assembly errors, enhances durability, and improves sensitivity by simplifying the assembly process and maintaining a stable rotation angle detection function, while avoiding separate rolling processes and ensuring reliable operation.
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 so as to be rotatably accommodated in the housing
Implementation Method 2
a sensor for detecting magnetism is connected thereto... a relative twist between the permanent magnet provided at the input shaft and the detection ring of the gear structure provided at the output shaft causes a change in area by which the permanent magnet and the detection ring face each other. Accordingly, a magnetic flux is changed in the detection ring and the change of the magnetic flux is detected by the sensor
Implementation Method 3
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
The present invention provides a torque sensor device disposed between an input shaft and an output shaft and configured to detect a torque between the input shaft and the output shaft through a relative rotation displacement therebetween. The torque sensor device includes: a housing configured to accommodate an end of the input shaft and an end of the output shaft and fixed in position to be able to perform a relative rotation with respect to the input shaft and the output shaft: 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 so as to be rotatably accommodated in the housing; 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; 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; and 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.