Board Unit Cover Latch Mechanism for Stable Engagement
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Solution Overview
Problem
Existing board units for vehicles face issues with the cover detaching from the case due to deformation of the cover's lateral walls, leading to unnecessary detachment and exposure of components.
Innovation Solution
A board unit design featuring engagement protrusions and recesses on the case and cover, combined with a latch piece and latch portion that restricts displacement, ensuring stable engagement and preventing cover detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If engagement projections and engagement holes are used to assemble the cover to the case, then the cover can be easily assembled, but the cover may deform outwardly when pressed from above, causing unnecessary detachment
Solution Approach 1:
The engagement structure is divided into two independent functional parts: engagement projections/holes for assembly and latch pieces/ports for retention. This segmentation allows each part to perform its specific function optimally - the engagement features provide easy assembly while the latch features prevent detachment under pressure, resolving the contradiction between ease of assembly and engagement stability.
Solution Approach 2:
The latch pieces are pre-positioned on the lateral walls of the cover and the latch ports are pre-formed on the case before assembly. During assembly, the latch pieces automatically engage with the latch ports before final tightening, creating a preliminary locking action that prevents outward deformation during subsequent pressing operations, thus ensuring both easy assembly and reliable retention.
2Reliability
If the cover is pressed from above, then electrical connection is ensured, but the lateral walls of the cover deform outwardly causing detachment
Solution Approach 1:
The latch pieces and latch ports create a preliminary anti-action force that counteracts the outward deformation tendency of the lateral walls when the cover is pressed from above. The latch structure is designed to engage before pressing occurs, establishing a pre-existing restraint that prevents the harmful outward deformation, thereby maintaining both electrical connection reliability and structural stability during operation.
3Device complexity
If engagement projections and holes are used, then assembly is simplified, but the cover cannot resist outward displacement under pressure
Solution Approach 1:
The engagement structure is divided into two independent functional parts: engagement projections/holes for assembly and latch pieces/ports for retention. This segmentation allows each part to perform its specific function optimally - the engagement features provide easy assembly while the latch features prevent detachment under pressure, resolving the contradiction between ease of assembly and engagement stability.
Solution Approach 2:
The engagement and retention functions are merged into a single integrated assembly process. The cover is assembled to the case using engagement projections and holes, while simultaneously the latch pieces engage with latch ports to provide retention. This merging allows both functions to work together without requiring separate assembly operations, maintaining simplicity while adding strength against outward displacement.
Data Source
AI summary
A board unit includes a case accommodating a circuit board. A power terminal connects a lead-out part of a bus bar with a connection terminal of an electric wire. A cover covers the power terminal and has a lateral wall overlapping a peripheral wall part. The lateral surface of the peripheral wall part and the lateral wall includes an engagement protrusion and an engagement recess to be engaged with the engagement protrusion. The lateral wall of the cover includes a latch piece at a position offset from the engagement protrusion or the engagement recess in a longitudinal direction and a latch portion to be latched with the latch piece which restricts displacement of the lateral wall of the cover in a direction away from the lateral surface of the peripheral wall part of the case.