Elastic Stopper Integrated into Jet Engine Case Cover

Solution Overview

Problem

In jet propelled watercraft, the engine's movement relative to the hull due to elastic deformation of dampers during rapid up-down motion causes contact issues, leading to increased component count and assembly complexity, as well as potential shock to the hull.

Innovation Solution

A stopper made of elastic material is integrated with the crankcase or case cover, positioned to face the hull across a space, reducing the need for a structurally independent attachment member and minimizing component count, while being placed at a forward position to effectively restrict engine movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a stopper is attached to the engine via a mount body that is structurally independent of the engine, then the stopper can effectively restrict engine movement, but the number of components and assembly process steps increases

Engineering Contradiction:

Improveengine movement restrictionVSAvoidnumber of components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The stopper attachment portion is integrated into the crankcase or case cover, merging the stopper mounting function with the engine housing. This eliminates the need for a separate mount body while maintaining the stopper's ability to restrict engine movement relative to the hull.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The crankcase or case cover serves multiple functions: it houses the crankshaft, provides structural support for the engine, and integrates the stopper attachment portion to restrict engine movement. This multi-functional design reduces the total number of components needed.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If a stopper is attached to the engine via a mount body that is structurally independent of the engine, then the stopper can effectively restrict engine movement, but the number of assembly process steps increases

Engineering Contradiction:

Improveengine movement restrictionVSAvoidassembly process efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The stopper attachment portion is integrated into the crankcase or case cover, merging the stopper mounting function with the engine housing. This eliminates the need for a separate mount body while maintaining the stopper's ability to restrict engine movement relative to the hull.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The stopper attachment portion is pre-integrated into the crankcase or case cover during engine manufacturing. This preliminary integration reduces the number of assembly steps required during watercraft assembly, as the stopper can be directly attached to the engine without requiring separate mounting operations.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If a structurally independent mount body is used to attach the stopper to the engine, then the stopper can be securely mounted, but the engine components housed in the hull are enlarged

Engineering Contradiction:

Improvestopper mounting securityVSAvoidengine size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The stopper attachment portion is integrated into the crankcase or case cover, merging the stopper mounting function with the engine housing. This eliminates the need for a separate mount body while maintaining the stopper's ability to restrict engine movement relative to the hull.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The stopper attachment portion is nested within or integrated into the existing crankcase or case cover structure. This allows the stopper to be securely mounted without adding external volume to the engine, as the attachment feature utilizes the existing structural space.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 reduces the number of components and assembly steps, effectively restricts engine movement, and mitigates shock to the hull by applying inertia force through the stopper attachment to the case cover.

Implementation Method 1

the engine approaches the hull because of the elastic deformation of the dampers when the jet propelled watercraft rapidly moves in an up-down direction during traveling

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the engine comes into contact with the hull via the stopper, and thus, a shock to the hull is reduced

Methodology Applied

Scientific EffectShock absorption: Damping

Data Source

PatentUS9505475B2Jet propelled watercraft

Publication Date: 2016.11.29 YAMAHA MOTOR CO LTD

AI summary

A jet propelled watercraft includes a front stopper that is disposed between a hull and an engine, that faces the hull across a space therebetween in an up-down direction, and that is made of an elastic material. The engine includes a crankshaft rotatable around a crankshaft axis, a crankcase that houses the crankshaft, a case cover attached to the crankcase, and a stopper attachment portion that is integral and unitary with the case cover and to which the front stopper is attached.