Boat Drive Sliding Seal for Annular Gap Water Ingress

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Solution Overview

Problem

Existing sealing arrangements for swiveling boat drives face challenges in reliably sealing annular gaps with variable dimensions while transmitting forces, leading to material compromise and increased wear due to relative movements between the boat drive and hull.

Innovation Solution

A sliding seal arrangement using elastic sealing elements that maintain constant prestress, with separate sealing elements compensating for movements in different directions along specifically oriented sealing surfaces, and an additional V-ring for external protection, ensuring reliable sealing and long service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If elastic sealing rings are used to seal the annular gap, then sealing effect is improved, but material selection becomes a compromise and wear increases due to relative movements

Engineering Contradiction:
Improvesealing effectVSAvoidservice life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The sealing arrangement is divided into multiple independent sealing elements (first sealing element and second sealing element) that can move independently relative to each other. This segmentation allows each sealing element to handle specific movement directions separately, reducing overall wear and improving service life while maintaining reliable sealing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing elements are designed to be movable relative to each other rather than fixed, allowing them to dynamically adapt to the variable annular gap dimensions caused by manufacturing tolerances, assembly tolerances, and operating conditions. This dynamic capability maintains effective sealing without excessive stress on the materials.

Inventive Principle:
Principle #15Dynamics

2Force

If elastic sealing rings are used to transmit forces, then force transmission is achieved, but sealing reliability deteriorates due to material compromise

Engineering Contradiction:
Improveforce transmissionVSAvoidsealing reliability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The sealing arrangement separates force transmission and sealing functions into different components. The movable support ring and elastic fastening elements handle force transmission, while the sealing elements focus solely on sealing. This functional segmentation eliminates the need for material compromise and improves sealing reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The movable support ring acts as an intermediary between the boat drive and the sealing elements. It transmits forces from the boat drive while allowing the sealing elements to maintain their sealing function independently, preventing force transmission from compromising sealing reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the boat drive is elastically suspended, then vibration-induced movements are allowed, but wear on sealing increases due to relative movements

Engineering Contradiction:
Improvevibration compensationVSAvoidservice life
Core Design Contradiction:
Adaptability or versatilityVSDuration of action of moving object

Solution Approach 1:

The sealing elements are designed with dynamic movement capabilities that match the vibration characteristics of the elastically suspended boat drive. The first and second sealing elements can move independently to compensate for vibration-induced displacements in different directions, maintaining sealing contact without excessive wear.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sealing arrangement accommodates parameter changes (displacements) in multiple directions caused by vibrations. By allowing the sealing elements to change their position parameters dynamically while maintaining contact pressure, the system compensates for vibrations without increasing wear.

Inventive Principle:
Principle #35Parameter changes

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

The sliding seal arrangement provides durable and improved sealing performance by maintaining consistent prestress on sealing elements, reducing wear and enhancing reliability, while allowing for horizontal and vertical movements, thus preventing water ingress and transmitting forces effectively through elastic fastening elements.

Implementation Method 1

the at least one first and the at least one second sealing element are arranged on a common carrier ring, wherein the carrier ring is displaceably arranged in the annular gap... the elastic sealing elements are continuously compressed with virtually the same preload

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a sealing arrangement for sealing the boat interior against water ingress is arranged in the region of the annular gap... The sealing elements slide along specifically oriented sealing surfaces

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2864193B1Boat drive
Publication Date: 2019.07.17 ZF FRIEDRICHSHAFEN AG
  • EP2864193B1 patent drawingFigure 1
  • EP2864193B1 patent drawingFigure 2

AI summary

The present invention relates to a boat drive (1) having a drive upper part (3) arranged inside a hull (2) and a pivotable drive lower part (4) arranged outside the hull (2), the boat drive (1) being guided through a base-side opening (6) in the hull (2) thus forming an annular gap (5) surrounding the boat drive on the peripheral side, and a sealing arrangement (10) being arranged in the region of the annular gap (5), said sealing arrangement (10) being designed as a slide seal.