Sealed Electric Screw Actuator for Submarine Sensor Tubes

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Solution Overview

Problem

Existing apparatus for raising sensor support tubes in submarines are not silent, corrosion-resistant, and are sensitive to electromagnetic disturbances, with complex construction, high maintenance requirements, and inefficiencies due to hydraulic systems.

Innovation Solution

A sealed electric actuator system with a screw mechanism driven by a rotating electric motor, using dielectric oil for lubrication and noise damping, and incorporating a position transducer away from electromagnetic sources, allowing for compact, low-maintenance, and silent operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If hydraulic actuating systems are used to raise sensor support tubes, then the tubes can be displaced vertically overcoming weight and friction, but the systems produce acoustic noise that may be detected by enemy submarines

Engineering Contradiction:
Improveacoustic noiseVSAvoidhydraulic system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces the hydraulic actuating system with an electric motor-driven screw mechanism. The electric motor (45) drives a screw (44) that rotates the rod (42), which moves the sensor support tube (20) vertically through the screw-nut mechanism (43). This substitution eliminates the hydraulic pump, oil reservoir, and associated piping, thereby eliminating acoustic noise from hydraulic operations while reducing system complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and removes the hydraulic system components (pump, reservoir, valves, hoses) from the actuating mechanism. By taking out the hydraulic system entirely and replacing it with an electric-mechanical system, the source of acoustic noise is eliminated while the core function of vertical displacement is preserved through the screw mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If hydraulic systems are used for actuation, then vertical displacement can be achieved, but the systems require complex construction with pumping stations and increased maintenance for oil purity protection

Engineering Contradiction:
Improvemaintenance requirementsVSAvoidconstructional complications
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The hydraulic system is replaced with an electric motor (45) driving a screw mechanism (44, 43). This substitution eliminates the need for hydraulic oil, pumping stations, and maintenance-intensive components. The electric-mechanical system requires only basic motor maintenance and has no fluid containment requirements, significantly reducing maintenance burden and constructional complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The dielectric oil (35) in the sealed housing (32) provides self-lubrication for the screw mechanism and seals (41a), eliminating the need for external hydraulic fluid supply systems. The system is self-contained with no external hydraulic connections, reducing maintenance requirements for fluid purity protection.

Inventive Principle:
Principle #25Self-service

3Weight of moving object

If hydraulic cylinders are used for actuation, then vertical movement can be produced, but the weight of the actuator and hydraulic circuit increases

Engineering Contradiction:
Improveactuator weightVSAvoidhydraulic circuit
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The heavy hydraulic cylinder and circuit are replaced with a compact electric motor (45) and screw mechanism (44, 43). The electric motor directly drives the screw, eliminating the need for large hydraulic cylinders, pumps, and extensive piping. This substitution dramatically reduces the weight of the actuating system while simplifying the overall construction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Loss of energy

If hydraulic systems are used for actuation, then power can be transmitted to move the tube, but efficiency is lost due to conversion from electrical to hydraulic form

Engineering Contradiction:
Improveenergy conversion efficiencyVSAvoidpower conversion device
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent eliminates the electrical-to-hydraulic power conversion step by using an electric motor (45) that directly drives the screw mechanism (44, 43). This direct electric-mechanical drive eliminates energy losses associated with hydraulic fluid compression, leakage, and heat generation, significantly improving overall system efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

5Measurement precision

If position transducers are placed near the sensor for position measurement, then measurement can be performed, but sensitivity to electromagnetic disturbances increases

Engineering Contradiction:
Improveposition measurementVSAvoidelectromagnetic disturbance sensitivity
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The position transducer (51) is extracted from the vicinity of the sensor and placed inside the sealed housing (32) near the electric motor (45). This relocation removes the transducer from the electromagnetic field of broadcasting antennas while maintaining measurement capability through the motor's rotation feedback.

Inventive Principle:
Principle #2Taking out (Extraction)

6Ease of manufacture

If complex hydraulic systems are used for actuation, then vertical displacement can be achieved, but the apparatus becomes expensive to produce and assemble

Engineering Contradiction:
Improveproduction costVSAvoidsystem complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The complex hydraulic system is replaced with a simple electric motor (45) and screw mechanism (44, 43). This substitution eliminates costly hydraulic components, fluid handling systems, and associated maintenance infrastructure. The electric-mechanical system uses standard off-the-shelf components, reducing production and assembly costs.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

7Reliability

If hydraulic systems are used for actuation, then the tube can be raised vertically, but corrosion resistance is compromised due to water infiltration risk

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidsealing requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The hydraulic system with its oil reservoir and piping is replaced with a sealed electric motor housing (32) containing dielectric oil (35) for lubrication. The sealed housing with magnetic seals (41a) prevents water infiltration, eliminating corrosion risks associated with hydraulic systems while using corrosion-resistant materials throughout.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 silent, corrosion-resistant, and low-maintenance apparatus that is easy to produce and install, with reduced weight and electromagnetic interference, optimizing movement control and assembly precision.

Implementation Method 1

the end of the rod, which is inside the housing, is connected to the screw nut of a screw actuator in turn connected to a rotating electric motor

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 2

two chambers, above and below the bearings, respectively. Said two chambers may contain oils, also with different and suitable characteristics for lubricating the seals

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 3

a rotating electric motor directly coupled to the said screw

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP1847454B1Electrically actuated apparatus for moving supports carrying sensors and the like in submarines
Publication Date: 2011.06.15 CALZONI
  • EP1847454B1 patent drawingFigure 1~2

AI summary

Apparatus for moving supports (10) carrying sensors (30) displaceable inside fixed guides (20) integral with the tower (1a) of submarines (1) and the like upon operation of an actuator (40), said actuator (40) consisting of an electric motor (45) coupled to one end of a screw actuator (44) on which a screw nut integral with a rod (42) is movable, the entire assembly being contained inside a housing (41) with seals (41a), from which the free end of said rod (42) protrudes for fastening to the tube (10).