Terminal Fitting Contact Member Rotation for External Matter Removal
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Solution Overview
Problem
Existing methods for establishing electrical connections, such as in automotive vehicles, fail to effectively remove external matter between contacts when large currents are involved, as the resilient deformation required to clear adherents is hindered by increased rigidity in the leaf spring members used.
Innovation Solution
A terminal fitting with a case and a resilient member, where the electrical contact member is configured to retreat and rotate upon contact, allowing it to shift relative to the mating contact and scrape off external matter without needing significant deformation, even at increased current levels, using a coil spring with an action axis aligned with the pressing force to maintain an inclined state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the plate thickness of the leaf spring member is increased to increase rigidity for large current applications, then the current carrying capacity is improved, but the resilient deformation capability deteriorates making it difficult to remove external matter
Solution Approach 1:
The electrical contact member is designed to rotate dynamically around a rotation axis when pressed by the mating contact. This rotational movement enables the contact surfaces to slide relative to each other, effectively removing external matter. The dynamic rotation mechanism allows thick, rigid contact members (suitable for high current) to still achieve effective external matter removal through motion rather than elastic deformation.
Solution Approach 2:
The invention introduces a rotational dimension around a rotation axis that is perpendicular to both the pressing force direction and the contact surface normal. This adds a new degree of freedom to the system, transforming the interaction from simple linear compression to combined compression plus rotation, enabling external matter removal without requiring resilient deformation of thick contact members.
2Ease of operation
If the electrical contact member is held in an inclined state non-perpendicular to the resilient member axis, then the rotation capability is improved with simple structure, but the force alignment becomes asymmetric
Solution Approach 1:
The electrical contact member is intentionally held in an asymmetric inclined state relative to the resilient member axis, rather than being perpendicular. This asymmetric positioning creates an offset between the pressing force application point and the rotation axis, generating a rotational moment that enables the contact member to rotate when pressed, facilitating external matter removal.
Solution Approach 2:
The electrical contact member is pre-positioned in an inclined state before the mating contact is inserted. This preliminary asymmetric positioning ensures that when the pressing force is applied during connection, the rotational moment is immediately generated, enabling automatic rotation and external matter removal without requiring additional actuation mechanisms.
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 ensures effective removal of external matter between contacts even at high current levels, allowing for reliable electrical connections by utilizing a simple structure that maintains the electrical contact member in an inclined state, preventing conduction failures.
Implementation Method 1
an electrical contact member (60) disposed in the case (20) to face the opening (31)... being pressed toward the opening (31) by a resilient member (40)
Implementation Method 2
the electrical contact member (60) retreats from the initial position while rotating to change an angle of inclination. Accordingly, the electrical contact member (60) shifts to be rubbed at a contact part with the mating contact (91). Thus, even if an external matter is present between the contact and the mating contact (91), that external matter is scraped off.
Data Source
AI summary
A terminal fitting includes a case (20) provided with an opening (31) into which a mating contact (91) is inserted, and an electrical contact member (60) disposed in the case (20) to face the opening (31) and configured to retreat while rotating to compress a resilient member (40) by being biased toward the opening (31) and pressed against the mating contact (91) by the resilient member (40).