Rotational Angle Detection Apparatus Welded Holding Member Distortion
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Solution Overview
Problem
Conventional rotational angle detection apparatuses experience distortion due to internal stress caused by cooling contraction, leading to increased magnetic hysteresis and reduced detection accuracy in permalloy components.
Innovation Solution
The use of fixedly welded holding members to prevent distortion in the detection member, eliminating internal stress and improving accuracy by sandwiching the detection member between the welded holding members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If insert-molding formation is used to fix the detection member, then ease of manufacture is improved, but internal stress and distortion occur during cooling
Solution Approach 1:
The holding member is divided into a resin holder and a metal holder. The resin holder is formed by insert-molding for ease of manufacture, while the metal holder is separately formed and then joined to the resin holder. This segmentation allows each part to be optimized for its specific function: the resin holder provides easy assembly, while the metal holder provides dimensional stability and prevents distortion during cooling.
Solution Approach 2:
A metal holder is introduced as an intermediary component between the detection member and the resin holder. The metal holder serves as a mediator that transfers the detection member to the resin holder while providing a stable, distortion-free structure. The metal holder is joined to the resin holder through a joining portion, creating a composite structure that combines the advantages of both materials.
2Ease of operation
If insert-molding formation is used to fix the detection member, then assembly simplicity is improved, but magnetic hysteresis increases due to internal stress
Solution Approach 1:
The holding member is segmented into resin and metal components. The resin holder maintains assembly simplicity through insert-molding, while the metal holder eliminates internal stress and magnetic hysteresis by providing a stable, stress-free mounting structure for the detection member.
Solution Approach 2:
The metal holder acts as an intermediary that decouples the assembly simplicity benefit from the harmful internal stress. It provides a stable mounting platform that prevents magnetic hysteresis while allowing the resin holder to maintain easy assembly characteristics.
3Measurement precision
If the detection member is made from permalloy, then detection sensitivity is improved, but magnetic loss increases due to distortion
Solution Approach 1:
The metal holder serves as a mediator that protects the permalloy detection member from distortion and internal stress. By providing a stable, stress-free mounting structure, the metal holder prevents magnetic hysteresis and energy loss in the permalloy material, thereby maintaining high detection accuracy.
Solution Approach 2:
The metal holder is specifically designed to provide localized support and stabilization to the detection member mounting area. This local quality enhancement prevents distortion in the critical region where the detection member is mounted, thereby preserving the magnetic properties of the permalloy.
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
This solution effectively reduces distortion and enhances detection accuracy in rotational angle detection, allowing for precise torque sensing in power steering systems.
Implementation Method 1
a Hall IC sensor that detects the magnetic flux between the magnetic collection rings
Implementation Method 2
a permanent magnet and a pair of yokes rotatable relative to each other, a pair of magnetic collection rings that guides a magnetic flux generated between the pair of yokes due to the relative rotation
Implementation Method 3
a first holding member and a second holding member are fixedly welded to each other with a detection member sandwiched between the first holding member and the second holding member
Data Source
AI summary
The present invention provides a rotational angle detection apparatus and a power steering apparatus capable of preventing or reducing distortion of a detection member and improving detection accuracy. A welded plate and a yoke holder are fixedly welded to each other with a pair of yokes sandwiched between the welded plate and the yoke holder.