Boat Propulsion Cover Assembly for Precise Cover Alignment

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Solution Overview

Problem

Conventional boat propulsion devices face challenges in precisely aligning and positioning a pair of facing covers and an upper cover due to variations in their positional relationships, affecting the design and functionality.

Innovation Solution

A boat propulsion device with a connecting part that connects a pair of facing covers and an upper cover through a hook mechanism, ensuring precise alignment and positioning, while allowing the upper cover to pivot and detach for maintenance, with features like elastic members to absorb vibration and suppress rattling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional covers are used without a connecting part and hook mechanism, then the structure is simpler, but the alignment and positioning precision of the covers deteriorates

Engineering Contradiction:
Improvealignment and positioning precision of coversVSAvoidstructural complexity of cover connection mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The hook and connecting part are designed to automatically engage and align the covers during assembly without requiring external alignment tools or complex positioning mechanisms. The covers self-align through the geometric constraint provided by the hook engaging with the connecting part, eliminating the need for separate alignment procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The connecting part acts as an intermediary element between the pair of facing covers and the upper cover. It provides a standardized engagement interface that mediates the connection, ensuring consistent positioning and alignment across all cover assemblies through the hook-connecting part interaction.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Shape

If the engaged portion between the connecting part and hook is exposed, then the structure is simpler, but the appearance design deteriorates

Engineering Contradiction:
Improveappearance design of boat propulsion deviceVSAvoidcomplexity of concealing mechanism
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

The engaged portion between the connecting part and hook is nested within the coverage area of the pair of facing covers and upper cover. The connecting part is positioned such that when the covers are assembled, the engagement interface is hidden inside the formed space, creating a clean external appearance while maintaining the structural connection.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Ease of repair

If the upper cover is fixed firmly to the facing covers, then the positional stability is improved, but the ease of maintenance deteriorates

Engineering Contradiction:
Improveease of maintenance of internal structureVSAvoidpositional stability of covers
Core Design Contradiction:
Ease of repairVSStability of the object's composition

Solution Approach 1:

The connection mechanism transitions from a static fixed state to a dynamic removable state. The hook and connecting part are designed to engage firmly during operation to maintain positional stability, but can be easily disengaged when maintenance is required, allowing the upper cover to be removed without permanent attachment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The cover assembly is segmented into removable components where the upper cover can be separated from the pair of facing covers through disengagement of the hook from the connecting part. This segmentation allows independent access to the internal structure for maintenance while maintaining firm connection during normal operation.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4520650B1Boat propulsion device and boat
Publication Date: 2026.04.29 YAMAHA MOTOR CO LTD
  • EP4520650B1 patent drawingFigure 1
  • EP4520650B1 patent drawingFigure 2
  • EP4520650B1 patent drawingFigure 3

AI summary

A pair of facing covers and an upper cover are aligned and positioned with high precision. A boat propulsion device includes: an internal structure; a pair of facing covers arranged to face each other through the internal structure in a first direction along a horizontal direction to form an opening to expose an upper portion of the internal structure; a connecting part extending in the first direction and connecting the pair of facing covers together; and an upper cover covering the opening and having a hook that engages the connecting part. A hook provided on the upper cover engages the connecting part that connects the pair of facing covers.