Spindle Nut Unit with Dual Gimbals for Aircraft High-Lift Systems

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Solution Overview

Problem

Existing spindle nut units for aircraft high-lift systems face challenges with maintenance and lubrication, as they are prone to contamination, require frequent grease refilling, and have limitations in stroke length and movement flexibility, leading to increased operating costs and maintenance efforts.

Innovation Solution

A spindle nut unit with two gimbals, where one gimbal transmits torque and the other axial force, integrated with a tube serving as a lubricant reservoir and featuring dynamic seals to prevent contamination, allowing for long strokes and flexible movement in all spatial directions without altering space requirements or transmission routing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If an external spindle is used in an open design, then the stroke length can be achieved, but the device is exposed to contamination and requires frequent maintenance

Engineering Contradiction:
Improvestroke lengthVSAvoidcontamination resistance
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The spindle is nested inside a protective housing that extends along the stroke path. The housing contains the spindle while allowing it to move axially, protecting it from contamination during the full stroke length without restricting movement

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

A flexible bellows cover surrounds the spindle and housing assembly, allowing axial movement while providing protection against dirt and splash water. The bellows expands and contracts with the stroke while maintaining the sealed environment

Inventive Principle:
Principle #30Flexible shells and thin films

2Ease of operation

If grease lubrication is used in an open design, then the device can operate, but the grease filling must be refilled regularly increasing maintenance effort

Engineering Contradiction:
Improveoperation capabilityVSAvoidmaintenance time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

A lubricant reservoir is integrated into the housing, automatically supplying lubricant to the ball screw mechanism during operation. The system self-lubricates without external intervention, eliminating the need for regular grease refilling and reducing maintenance time

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

A lubricant circulation system using oil under pressure delivers lubricant to the ball screw bearing surfaces. The oil is recirculated and filtered, providing continuous lubrication and cooling without manual intervention

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Adaptability or versatility

If cardan joints are used to enable pivoting movement, then movement flexibility is achieved, but the design complexity increases

Engineering Contradiction:
Improvemovement flexibilityVSAvoiddesign complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The housing is designed with universal pivot joints at both ends, allowing the entire actuator assembly to pivot and adapt to different mounting configurations and movement requirements. This multi-functional design provides flexibility without requiring complex internal mechanisms

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 significantly reduces maintenance needs through oil lubrication, effective lubricant management, and flexible movement capabilities, minimizing contamination and wear, while maintaining efficient torque and load transmission.

Implementation Method 1

The tube can be manufactured in one piece with the spindle nut and additionally or alternatively comprise a connection in a region opposite the spindle nut for connecting or connecting to the first cardanic suspension

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

featuring dynamic seals to prevent contamination

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Implementation Method 3

the two gimbals have a common center or are designed with a common center and that the first gimbal is designed to transmit torque to the spindle nut or the spindle and the second gimbal to transmit force to the spindle nut

Methodology Applied
Scientific EffectSpherical mechanism: Gimbal

Data Source

PatentEP3318781B1Spindle nut unit for driving a lift system of an airplane
Publication Date: 2020.09.02 LIEBHERR AEROSPACE LINDENBERG GMBH
  • EP3318781B1 patent drawingFigure 1a~1c
  • EP3318781B1 patent drawingFigure 2a~2d
  • EP3318781B1 patent drawingFigure 3a~3c

AI summary

Spindle nut unit (10) for driving a high-lift system of an aircraft. The invention relates to a spindle nut unit (10) for driving a high-lift system of an aircraft, in particular an airplane, wherein the spindle nut unit (10) comprises a spindle nut (11) and a spindle (12) as well as two gimbal mounts (1), wherein the spindle nut unit (10) can be coupled to connections of the aircraft via the two gimbal mounts (1) and wherein the two gimbal mounts (1) have a common center point (100).