Lower Unit Flexible Conduit Routing for Steerable Marine Propulsion

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Solution Overview

Problem

Marine propulsion devices face challenges in independently steering the lower unit with respect to the powerhead, which complicates the connection and maintenance of sensors and fluid supply systems due to the rotational movement, leading to potential issues with lubricant level monitoring and water ingress.

Innovation Solution

A flexible conduit with slack is used to connect the stationary and rotatable portions, allowing for the extension of wiring harnesses and fluid conduits between the steering housing and steering column, enabling the integration of sensors and maintaining a sealed environment despite rotational movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the lower unit is steerable independently of the powerhead, then the steering control is improved, but the connection and maintenance of sensors and fluid supply systems becomes complicated

Engineering Contradiction:

Improvesteering controlVSAvoidconnection and maintenance of sensors and fluid supply systems

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent employs flexible conduits to connect the stationary powerhead to the rotatable lower unit. These flexible conduits allow rotational movement while maintaining sealed fluid and electrical connections, eliminating the complexity of rigid mechanical linkages and simplifying both installation and maintenance of the steering system.

Inventive Principle:

Principle #30Flexible shells and thin films

2Ease of operation

If rotational movement is allowed between stationary and rotatable portions, then steering functionality is improved, but sealing and protection against water ingress becomes difficult

Engineering Contradiction:

Improvesteering functionalityVSAvoidsealing and protection against water ingress

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent utilizes flexible sealed conduits that maintain water-tight seals while accommodating rotational movement between the stationary powerhead and rotatable lower unit. This flexible sealing approach prevents water ingress during steering operations while maintaining system reliability.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent introduces flexible conduits as intermediary elements between the stationary and rotatable portions. These conduits act as mediators that transmit fluids and electrical signals while isolating the rotational interface from water, ensuring reliable sealing without compromising steering functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stability of the object's composition

If rigid connections are used between stationary and rotatable portions, then structural stability is improved, but rotational movement and steering become restricted

Engineering Contradiction:

Improvestructural stabilityVSAvoidrotational movement and steering

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent replaces rigid mechanical connections with flexible sealed conduits that can accommodate rotational movement. These flexible connections maintain sufficient structural stability for fluid and electrical transmission while enabling the full range of steering motions required for operational versatility.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent transitions from static rigid connections to dynamic flexible connections that adapt to rotational movement. The flexible conduits dynamically adjust their configuration during steering operations, maintaining structural integrity while enabling the necessary adaptability for independent lower unit rotation.

Inventive Principle:

Principle #15Dynamics

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 solution allows for reliable power and fluid supply to sensors within the lower unit, preventing water ingress and enabling effective lubricant level monitoring, thus enhancing the operational reliability and longevity of the marine propulsion system.

Implementation Method 1

A flexible conduit with slack is used to connect the stationary and rotatable portions

Methodology Applied

Scientific EffectFlexibility: Elasticity

Implementation Method 2

enabling the integration of sensors and maintaining a sealed environment despite rotational movement

Methodology Applied

Scientific EffectSealing: Physical Containment

Data Source

PatentUS11866133B1Marine propulsion device with flexible conduit in lower unit

Publication Date: 2024.01.09 BRUNSWICK CORP

AI summary

A marine propulsion device has a powerhead, a driveshaft powered by the powerhead, a lower unit, and a propeller shaft supported in the lower unit and in torque transmitting relationship with the driveshaft. The marine propulsion device also has a steering column through which the driveshaft extends and to which the lower unit is coupled. The steering column is configured to rotate the lower unit with respect to the powerhead. There is a steering housing through which the steering column extends, the steering housing being stationary with respect to the powerhead. A flexible conduit, for example a wiring harness, extends through an aperture in the steering housing and through an aperture in the steering column. The flexible conduit has slack between the steering housing and the steering column.