Integrated Magnetic Switch Sealing Against Contaminants
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Solution Overview
Problem
Vehicle starter motors with soft-start engagement systems face issues due to contaminants like motor oil, water, and dust entering the integrated magnetic switch (IMS), which interfere with electric contacts and limit the movement of the pull-in coil, as existing IMS designs are not adequately sealed to prevent such contaminants.
Innovation Solution
An integrated magnetic switch assembly with a sealing member and seal elements positioned between power terminals and a cover assembly, along with a funnel-like cross-section sealing member to secure conductors, effectively prevents foreign debris from entering the IMS assembly, ensuring a robust seal and maintaining the integrity of the electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the IMS is mounted directly to the solenoid and starter motor to limit current draw, then the starter motor can operate with reduced current (2-4 amps), but contaminants enter the IMS and interfere with electric contacts and coil movement
Solution Approach 1:
A sealing member in the form of an O-ring or gasket is positioned at the interface between the cover assembly and winding assembly portion, creating a flexible barrier that prevents contaminants from entering the IMS while allowing for thermal expansion and manufacturing tolerances
Solution Approach 2:
The sealing member acts as an intermediary element between the external environment and the IMS internal components, blocking the path of contaminants without interfering with the electrical or mechanical function of the IMS
2Device complexity
If the IMS is integrated directly into the starter motor, then device complexity is reduced, but the IMS is exposed to contaminants from the vehicle starter environment
Solution Approach 1:
The IMS is divided into separate assemblies (cover assembly and winding assembly portion) that are joined together with a sealing interface, allowing the IMS to be integrated into the starter motor while creating a segmented barrier against contaminants
Solution Approach 2:
The sealing member creates a protective barrier at the interface between IMS components, enabling direct integration into the contaminant-prone starter motor environment while preventing contaminant ingress
3Object-affected harmful factors
If a sealing member with a smaller diameter opening is used to prevent contaminant entry, then contaminant protection is improved, but conductor passage through the rivet terminal becomes more difficult
Solution Approach 1:
The sealing system is segmented into multiple components (sealing member on rivet terminal, additional sealing element at power terminal interface), allowing the rivet terminal opening to be small for contamination protection while the conductor is guided through by the sealing member before being secured
Solution Approach 2:
The sealing member serves as an intermediary that the conductor must pass through, and the sealing element at the power terminal interface acts as a second intermediary that guides and seals the conductor, maintaining both contamination protection and manufacturability
Data Source
AI summary
An integrated magnetic switch assembly includes a winding assembly portion having a housing, and a cover assembly mounted to the housing. The cover assembly includes at least one rivet terminal and at least one power terminal The at least one rivet terminal includes a body that extends through the cover assembly. The body has a first end that extends to a second end, and an opening that includes a first diameter that extends from the first end to the second end. A sealing member is positioned at the first end of the body about the opening of the at least one rivet terminal. The sealing member includes an opening having a second diameter that is smaller than the first diameter. A sealing element is positioned between the at least one power terminal and the cover assembly.