Rotation Angle Detecting Unit Stress Management
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Solution Overview
Problem
Conventional rotation angle detecting units face issues with thermal stress and forming stress affecting the accuracy of magnetism detecting elements, leading to increased costs for examination and material costs due to the use of resin and elastic bodies in the molding process.
Innovation Solution
A rotation angle detecting unit with an integrated circuit package, a sealing body, and leads, where the IC package is press-fitted into a resin-formed supporting part with a predetermined pressure, avoiding forming stress and thermal stress, and using a resin-covered covering member with a fixing and supporting part to stabilize the position of the magnetism detecting element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the IC package is molded in the covering member made of resin, then the position of the magnetism detecting element is stabilized, but thermal stress and forming stress deteriorate the temperature characteristics and may damage the magnetism detecting element
Solution Approach 1:
The covering member is divided into two separate functional parts: a fixing part that attaches to the supporting body and a supporting part that holds the IC package. This segmentation allows each part to be optimized independently, reducing stress concentration and improving overall reliability while maintaining position stability.
Solution Approach 2:
An elastic body is introduced as an intermediary component between the IC package and the supporting part. This elastic body acts as a stress buffer that absorbs thermal expansion differences and mechanical stresses, protecting the magnetism detecting element from damage while maintaining stable positioning.
2Device complexity
If the IC package is molded in the covering member, then integration is improved, but forming stress is applied to the IC package and magnetism detecting element
Solution Approach 1:
The covering member is segmented into a fixing part and a supporting part, allowing the IC package to be mounted on the supporting part rather than being fully molded into the covering member. This reduces forming stress while maintaining integration benefits.
Solution Approach 2:
The elastic body serves as a mediator between the IC package and the supporting part, providing a compliant interface that reduces forming stress during assembly while maintaining secure attachment and integration.
3Reliability
If an elastic body is used to cover the IC package, then protection is improved, but material costs and processing costs increase
Solution Approach 1:
The covering member is segmented so that only the necessary supporting part contacts the IC package, rather than using a complete elastic body covering. This reduces material usage and processing costs while providing adequate protection and stress relief.
Solution Approach 2:
Instead of uniformly covering the IC package with elastic material, the elastic body is applied only in specific locations where stress relief and protection are most needed, optimizing the balance between protection and cost.
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 configuration reduces examination costs, stabilizes the position of the magnetism detecting element, improves detection accuracy, and prevents damage from thermal stress, while maintaining the integrity of the magnetism detecting element.
Implementation Method 1
a magnetism detecting element configured to output a signal, which is in accordance with a change of a magnetic field generated upon rotation of a magnetism generating means
Implementation Method 2
the IC package is press-fitted into the supporting part after its formation, so that the IC package is supported by the supporting part with a predetermined pressure applied to a part of an outer wall of the sealing body
Data Source
AI summary
A rotation angle detecting unit includes an IC package having a magnetism detecting element, a sealing body, and leads; and a covering member having a fixing part and a supporting part, which are integrally formed from resin. The element outputs a signal according to change of a magnetic field generated upon rotation of a magnetism generating device attached to a detection object. The sealing body covers the element. The leads are connected to the element, and project from the sealing body. The fixing part is fixed to a supporting body so that the covering member is attached to the supporting body. The supporting part supports the package such that the element can output the signal. The package is press-fitted into the supporting part after its formation, so that the package is supported by the supporting part with a predetermined pressure applied to part of an outer wall of the sealing body.