Rotational Speed Sensor Positioning via Molded Case Structure
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Solution Overview
Problem
Conventional rotational speed detecting sensors face challenges in ensuring reliable positioning of the detecting member relative to the portion to be detected, particularly in the radial direction of the rotor, leading to potential shifts and suboptimal detecting sensitivity due to issues with resin molding and handling during manufacturing.
Innovation Solution
A rotational speed detecting sensor design that includes a detecting portion with a magnetized member, a fix portion formed by resin molding, and a case with a housing portion and positioning features to securely position the detecting member within the case, preventing movement during molding and ensuring accurate alignment with the rotor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the detecting member is positioned within the case using conventional resin molding, then the case can be formed with the fix portion, but the positioning of the detecting member relative to the fix portion becomes unreliable and may shift during manufacturing
Solution Approach 1:
The patent applies preliminary action by pre-positioning the detecting member within the case before the resin molding process. The case is designed with a predetermined positioning structure that secures the detecting member in the correct location prior to molding, ensuring that the detecting member maintains its optimal position relative to the fix portion throughout the manufacturing process.
Solution Approach 2:
The patent introduces an intermediary positioning structure within the case that acts as a mediator between the detecting member and the resin molding process. This positioning structure prevents the detecting member from shifting during resin supply and handling operations, while still allowing the conventional resin molding process to be used for forming the fix portion.
2Device complexity
If the case is formed with the fix portion using resin molding, then the fix portion can be integrated with the case, but the relative position of the detecting member and the portion to be detected may shift due to resin supply and handling
Solution Approach 1:
The patent applies preliminary action by pre-positioning the detecting member within the case before the resin molding process. The case is designed with a predetermined positioning structure that secures the detecting member in the correct location prior to molding, ensuring that the detecting member maintains its optimal position relative to the fix portion throughout the manufacturing process.
Solution Approach 2:
The patent applies beforehand cushioning by designing the case with a positioning structure that provides protection and stability to the detecting member during the resin molding process. This positioning structure prevents unwanted movement and maintains the optimal relative position between the detecting member and the portion to be detected, cushioning against the potential harmful effects of resin supply and handling.
3Productivity
If the detecting member is positioned in the radial direction without reliable positioning, then the sensor can be manufactured, but optimal detecting sensitivity cannot be obtained
Solution Approach 1:
The patent applies preliminary action by pre-positioning the detecting member within the case before the resin molding process. The case is designed with a predetermined positioning structure that secures the detecting member in the correct location prior to molding, ensuring that the detecting member maintains its optimal position relative to the fix portion throughout the manufacturing process.
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 ensures reliable positioning of the detecting member relative to the rotor, enhancing detecting sensitivity and stability by restricting movement during resin molding and maintaining precise alignment, thus improving the sensor's performance.
Implementation Method 1
The detecting member detects a rotational speed of a rotor by detecting amount of a magnetic flux, which is varied in response to a rotation of a magnetized portion to be detected
Data Source
AI summary
A rotational speed detecting sensor includes a detecting portion having a detecting member provided facing a magnetized portion to be detected, the detecting portion for detecting variations of a magnetic flux generated by a rotation of the portion to be detected, a fix portion for fixing the detecting member, the fix portion being formed by means of molding and a case, a first end of which is closed and a second end of which is opened. The case includes a housing portion recessed toward the first end of the case from an opening portion side of the case, the housing portion for housing the detecting member, and a positioning portion for restricting a movement of the case in a mold in a direction toward the opening portion side of the case from the first end of the case.