Shield Unit Rotation Mechanism for Low Contact Resistance
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Solution Overview
Problem
Conventional shield units face challenges in securing sufficient sliding distance for the braid to reduce contact resistance without increasing the size of the shield unit, as the sliding distance is limited to the attachment direction, and increasing the size is not feasible.
Innovation Solution
Incorporating a rotation unit between the cylinder and the holder, which allows the holder to rotate in the circumferential direction, enabling additional sliding distance without enlarging the shield unit's size, and including a guide groove and protrusion for accurate attachment and visual confirmation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sliding distance in the attachment direction is increased to secure sufficient sliding distance for the braid, then the contact resistance decreases, but the shield unit increases in size
Solution Approach 1:
The patent introduces a rotation unit that enables the holder to rotate in the circumferential direction of the cylinder, adding a rotational dimension to the attachment process. This allows the braid to slide not only in the attachment direction but also in the circumferential direction, thereby securing sufficient sliding distance without increasing the length of the shield unit in the attachment direction.
2Reliability
If the holder is merely attached to the cylinder without rotation, then the device complexity is reduced, but the sliding distance is insufficient to decrease resistance
Solution Approach 1:
The patent transforms the static attachment mechanism into a dynamic one by introducing a rotation unit. The holder can now rotate in the circumferential direction during attachment, creating a dynamic sliding action that effectively removes oxidation coating and decreases contact resistance. This dynamic approach enhances electrical connection reliability while maintaining reasonable device complexity.
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 a sufficient sliding distance for the braid, enhancing the electrical connection reliability and preventing oxidation coating issues without increasing the shield unit's dimensions, thus improving the overall performance.
Implementation Method 1
The sliding distance traveled by the surface of the braid is limited to a distance in an attachment direction in which the rear holder is attached to the cylinder. This may make it impossible to secure the sliding distance long enough to decrease the resistance.
Implementation Method 2
The surface of the braid is sometimes covered with an oxidation coating in the shield unit according to Japanese Unexamined Patent Application Publication No. 2012-521068. The formed oxidation coating increases the contact resistance and blocks the electrical connection between the shield shell and the braid. The oxidation coating formed on the surface of the braid as described above is removed by sliding the surface of the braid under a degree of pressing force.
Data Source
AI summary
A shield unit includes: a braid having a contact portion arranged in contact with a cylinder of a shield shell; a holder inserted in the cylinder and attached to the cylinder in contact with the contact portion, the holder attached to the cylinder electrically connecting the shield shell to the braid; and a rotation unit provided between the cylinder and the holder, the rotation unit being configured to make the holder rotate in a circumferential direction of the cylinder and make the cylinder and the contact portion slide relatively to each other until completion of attaching the holder to the cylinder.