Hydraulic Actuator With Threaded Drive for Precise High-Load Positioning

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Solution Overview

Problem

Hydraulic actuators lack precise positional adjustability and threaded mechanical actuators fail under high load forces due to the trade-off between thread strength and adjustment resolution.

Innovation Solution

A compact and lightweight adjustable actuator system combining a high TPI threaded drive mechanism with a hydraulic piston system, allowing for force multiplication and precise positional control by coupling a master actuator with a slave actuator, enabling high output forces with fine adjustment resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If threaded mechanical actuators with high thread count are used to achieve precise positional control, then manufacturing precision is improved, but the actuator fails under high load forces

Engineering Contradiction:
Improvepositional control precisionVSAvoidload bearing capacity
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent combines a threaded drive mechanism (for precision) with a hydraulic actuation system (for strength) into a single integrated actuator. The threaded bolt engages with a nut that is hydraulically actuated, merging the precision positioning capability of mechanical threads with the high force capability of hydraulic systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a hydraulic system to actuate the threaded mechanism. A piston moves within a cylinder and transfers hydraulic pressure to the nut, which then rotates the threaded bolt. This hydraulic actuation provides the high force multiplication needed to overcome the limitation of threaded actuators under high load.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Strength

If hydraulic actuators are used to handle high load forces, then strength is improved, but positional adjustability precision deteriorates

Engineering Contradiction:
Improveload bearing capacityVSAvoidpositional control precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent merges a hydraulic actuation system (providing strength) with a threaded drive mechanism (providing precision). The hydraulic piston moves the nut along the threaded bolt, and the thread pitch determines the precise positional adjustment, while the hydraulic system provides the force multiplication.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The threaded bolt and nut assembly serve as an intermediary mechanism between the hydraulic piston and the final output. The hydraulic system provides force to move the nut, and the threaded mechanism converts this motion into precise linear displacement with high positional control.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If high TPI threaded drive mechanism is used to achieve fine adjustment resolution, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improveadjustment resolutionVSAvoidmechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines the high TPI threaded drive mechanism with a hydraulic actuation system in a single integrated unit. This merging allows the complex precision mechanism to be actuated by a relatively simple hydraulic piston, reducing the overall operational complexity while maintaining fine adjustment resolution.

Inventive Principle:
Principle #5Merging (Combining)

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 system achieves high precision and high load handling capabilities, providing a compact and lightweight solution for applications requiring both precise adjustment and significant force, with the ability to multiply input force proportionally.

Implementation Method 1

The first piston comprises a threaded portion disposed in a threaded aperture of the first cylinder and is manually rotatable by the drive mechanism

Methodology Applied
Scientific EffectThreading: Screw

Implementation Method 2

a first fluid line coupling the first fluid reservoir to the fourth fluid reservoir, and a second fluid line coupling the second fluid reservoir to the third fluid reservoir

Methodology Applied
Scientific EffectHydraulic pressure transmission: Hydraulic Press

Data Source

PatentEP3214319B1High-precision hydraulic actuator
Publication Date: 2022.09.07 LOCKHEED MARTIN CORP
  • EP3214319B1 patent drawingFigure 1
  • EP3214319B1 patent drawingFigure 2A
  • EP3214319B1 patent drawingFigure 2B

AI summary

An apparatus includes a drive mechanism (210), a first cylinder (220) comprising a first piston (250) coupled to the drive mechanism (210), and a second cylinder (230) comprising a second piston (240). The first cylinder (220) includes a first fluid reservoir (224) and a second fluid reservoir (226), with the first piston (250) disposed between the first fluid reservoir (224) and the second fluid reservoir (226). The second cylinder (230) includes a third fluid reservoir (234) and a fourth fluid reservoir (236), with the second piston (240) disposed between the third fluid reservoir (234) and the fourth fluid reservoir (236). The apparatus further includes a first fluid line (260) coupling the first fluid reservoir (224) to the fourth fluid reservoir (236), and a second fluid line (270) coupling the second fluid reservoir (226) to the third fluid reservoir (234). The first piston (250) comprises a threaded portion (252) disposed in a threaded aperture (221) of the first cylinder (220).