Tidal Power Rotor Joint Sealing for Backlash-Free Torque Transfer

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Solution Overview

Problem

Tidal power plants face challenges in maintaining a rotationally secure connection between rotor shaft and rotor hub due to seawater penetration, which causes friction lacquer removal and particle detachment, leading to force-transmission losses and backlash.

Innovation Solution

A friction-increasing element with hard particles like diamond, titanium boride, or tungsten carbide is used between the components, combined with a sealing material to prevent water ingress and particle detachment, ensuring a rotationally secure connection even in harsh environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a friction-increasing element with hard particles is used between flange surfaces, then a rotationally secure connection is achieved, but the hard particles detach and are washed out by seawater

Engineering Contradiction:

Improverotationally secure connectionVSAvoidhard particles washout

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

A sealing element is introduced as an intermediary component between the friction-increasing element and the external seawater environment. This sealing element prevents seawater from directly contacting the hard particles, thereby preventing particle detachment and washout while maintaining the rotationally secure connection provided by the friction-increasing element.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If a screw connection alone is used between rotor shaft and rotor hub, then the components can be assembled, but no rotationally fixed connection is produced due to backlash

Engineering Contradiction:

Improveassembly capabilityVSAvoidrotational fixation

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The solution merges two different connection mechanisms: a screw connection for assembly and positioning, combined with a friction-increasing element for rotational fixation. The screw connection brings the flange surfaces into contact, while the friction-increasing element with hard particles creates high friction to prevent relative rotation, eliminating backlash while maintaining ease of assembly.

Inventive Principle:

Principle #5Merging (Combining)

3Duration of action of stationary object

If the friction-increasing element is exposed to seawater, then the connection can be maintained, but the friction lacquer is removed and particles are detached

Engineering Contradiction:

Improveconnection durabilityVSAvoidseawater corrosion

Core Design Contradiction:

Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The sealing element serves as a protective intermediary barrier that isolates the friction-increasing element from the harmful seawater environment. This allows the friction-increasing element to maintain its rotational connection function for extended periods without degradation from seawater exposure, preventing both friction lacquer removal and particle detachment.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sealing element creates an inert or protected environment around the friction-increasing element, preventing seawater (a harmful external medium) from contacting the friction surfaces. This protective environment preserves the integrity of the friction-increasing element and maintains connection durability in the harsh marine environment.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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 solution provides a reliable, cost-effective, and maintainable rotationally secure connection that prevents particle washout and maintains torque transmission without backlash, suitable for underwater and damp environments.

Implementation Method 1

a friction-increasing element (10) is disposed between the first assembly surface (6) and the second assembly surface (8)... these hard particles press in or embed within the surfaces to be connected to each other and thus connect the two components to each other in a friction-fit manner

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS11788595B2Machine assembly, in particular a tidal power plant

Publication Date: 2023.10.17 AB SKF SKF PATENT DEPARTMENT

AI summary

A machine assembly includes a first machine component and a second machine component, the first machine component including a first installation surface and the second machine component including a second installation surface. The first and second installation surfaces are mounted against one another in the assembly. A friction-increasing element is provided in the assembly between the first installation surface and the second installation surface. Further, in the assembled state, a sealing material is introduced into an intermediate space between the first and second installation surfaces.