Ship Drive Lubrication via Flexible Lines

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Solution Overview

Problem

Existing ship propulsion systems face challenges in efficiently supplying and storing lubricating oil, particularly in withstanding vibrations and temperature-related volume changes, while ensuring air venting and preventing oil leakage during filling and oil changes.

Innovation Solution

The system incorporates a rotatable lower drive unit with lubricating oil channels connected via flexible lines to a lubricating oil container located away from the bevel gear, featuring a transparent housing for level monitoring and air venting, and a rotary decoupling mechanism to manage oil flow and temperature changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lubricating oil channels are rigidly connected to the gear housing and drive shaft, then the oil supply structure is simple and mechanically strong, but the system cannot withstand vibrations and temperature-related volume changes

Engineering Contradiction:
Improvevibration resistanceVSAvoidoil channel structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies flexible hoses instead of rigid channels to connect the lubricating oil tank with the gear housing and drive shaft. These flexible hoses can accommodate vibrations and thermal expansion while maintaining fluid connection, thus resolving the contradiction between mechanical strength and vibration resistance.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The oil supply system transitions from a static rigid structure to a dynamic flexible structure that can adapt to vibrations and volume changes. The flexible hoses allow the system to dynamically respond to operational conditions without compromising structural integrity.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the lubricating oil tank is placed close to the bevel gear for easy oil supply, then the oil delivery distance is short, but the tank is exposed to vibrations and heat from the propulsion system

Engineering Contradiction:
Improveoil storage stabilityVSAvoidoil supply convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The flexible hose acts as an intermediary element that connects the remotely positioned oil tank to the gear system. This mediator allows the tank to be positioned away from vibrations and heat while still providing effective oil supply to the bevel gear.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If rigid oil channels are used throughout the system, then the manufacturing precision can be maintained, but the system cannot accommodate temperature-related volume changes without oil leakage

Engineering Contradiction:
Improvethermal expansion accommodationVSAvoidoil channel alignment
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Flexible hoses replace rigid oil channels, allowing the system to accommodate thermal expansion and volume changes without compromising manufacturing precision. The flexibility of the hoses compensates for dimensional changes while maintaining proper oil flow paths.

Inventive Principle:
Principle #30Flexible shells and thin films

4Reliability

If the lubricating oil tank is positioned away from the upper bevel gear, then vibrations cannot directly reach the tank, but the oil supply line becomes longer and more complex

Engineering Contradiction:
Improvevibration isolationVSAvoidoil channel configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The flexible hose provides a simple yet effective connection that isolates the oil tank from vibrations while avoiding the need for complex routing or intermediate components. The hose's flexibility naturally accommodates the increased distance without adding structural complexity.

Inventive Principle:
Principle #30Flexible shells and thin films

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 design ensures reliable and vibration-resistant oil supply and storage, allowing for easy oil changes and air escape, preventing damage from oil leakage and ensuring continuous lubrication of the propulsion system.

Implementation Method 1

at least one lubricating oil channel of the upper drive unit (7a) is connected via a flexible line (28a, 28b) to a lubricating oil tank (13a, 13b)

Methodology Applied
Scientific EffectFlexibility: Elasticity

Implementation Method 2

The transparency of the housing also allows ship personnel to determine, based on the appearance of the lubricating oil, whether water is present in the lubricating oil

Methodology Applied
Scientific EffectTransparency:

Implementation Method 3

at least one closable venting channel (32a, 32b) is formed to discharge air from the oil-carrying spaces of the ship's propulsion system (1)

Methodology Applied
Scientific EffectPressure equalization: Pascal's Law

Implementation Method 4

an oil collection chamber (33), which can rotate relative to the ship's hull, that is fluidically connected to the stationary lubricating oil channel in the wall of the supporting structure of the upper drive unit (7a) via a rotary decoupling

Methodology Applied
Scientific EffectRotational decoupling:

Data Source

PatentEP2398699B1Ship drive comprising a drive unit that can be pivoted under water
Publication Date: 2015.10.21 ZF FRIEDRICHSHAFEN AG
  • EP2398699B1 patent drawingFigure 1
  • EP2398699B1 patent drawingFigure 2

AI summary

The invention relates to a ship drive (1) comprising an upper drive unit (7a) arranged in the ship's hull and a lower drive unit (7a) arranged outside the ship's hull, at least the lower drive unit (7b) being mounted pivotably in relation to the ship's hull. An input shaft (12) of the upper drive unit (7a) can be driven by a drive motor, and at least one propeller (18, 19) can be driven by an output shaft (37) arranged in the lower drive unit (7b). A vertical drive shaft (21) is connected, in a driving manner, to the input shaft (12) of the upper drive unit (7a) by means of an upper angular gear (4), and to the output shaft (37) of the lower drive unit (7b) by means of a lower angular gear (4). The upper and lower drive units (7a, 7b) comprise interconnected lubricant channels, the lubricant being introduced into the upper drive unit (7a) and carried away by same. In order to further improve the ship drive, at least one lubricant channel (29a, 29b) of the upper drive unit (7a) is connected to a lubricant container (13a, 13b) arranged in the region of the upper drive unit (7a), by a flexible line (28a, 28b).