Unit Attachment Structure With Slanting Surfaces For Assembly
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Solution Overview
Problem
The existing unit attachment structure for evaporated fuel treatment devices faces issues with ease of assembly due to projections being erroneously fitted into slits when rotated, leading to difficulty in releasing the unit from the case.
Innovation Solution
The structure incorporates slanting surfaces on the slits and a protruding part with a controlled length to facilitate easy release of projections from slits and prevent rotation-induced looseness, ensuring the unit can be re-assembled efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a snap-fit structure with projections and slits is used to attach the unit to the case, then the unit can be securely fixed to the case, but the projection may be erroneously fitted into the slit when the unit is rotated during assembly, making it difficult to release and reassemble
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameters of the slit to include a slanting surface with a specific inclination angle (α). This angular parameter change allows the slit to accommodate rotational misalignment during assembly while maintaining secure fixation in the proper position, thereby resolving the contradiction between reliable fixation and ease of assembly.
Solution Approach 2:
The patent applies the inversion principle by designing the slit with a slanting surface that reverses the typical engagement mechanism. Instead of the projection forcing the slit to deform, the slanting surface guides the projection along an inclined path, allowing easy entry during rotation and secure locking in the correct position, thus improving ease of assembly while maintaining reliability.
2Reliability
If the projection is designed to fit into the slit for securing the unit, then fixation is achieved, but the projection becomes difficult to release from the slit when erroneously fitted due to rotation
Solution Approach 1:
The patent modifies the slit geometry by introducing a slanting surface with a controlled inclination angle, changing the engagement parameters from a simple rectangular slot to an angled guide. This parameter change enables the projection to slide easily along the slant during reassembly while maintaining stable fixation when properly engaged, resolving the contradiction between fixation stability and ease of reassembly.
3Adaptability or versatility
If the unit is designed to be inserted into the case with engagement portions, then the attachment function is achieved, but rotation during insertion causes the projection to fit into the slit erroneously, requiring complex release mechanisms
Solution Approach 1:
The patent simplifies the assembly mechanism by changing the slit geometry to include a slanting surface with a specific inclination angle. This parameter change allows the slit to passively guide the projection during rotational insertion and automatically lock in the correct position, eliminating the need for complex release mechanisms while maintaining the attachment function and accommodating rotational misalignment.
Data Source
AI summary
Provided is a unit attachment structure. The unit attachment structure includes a case and a unit to be inserted into the case. The case includes an opening, paired slits, and a first engagement portion. The unit includes a projection projecting from a facing surface of the unit, and a second engagement portion. At least one of one slit of the paired slits or the projection includes a slanting surface formed along a circumferential direction.