Force Transmission Unit with Ball Socket and Magnetic Damping

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Solution Overview

Problem

Existing force transmission assemblies in aircraft piloting systems face challenges with bulk size and precision due to play and friction hysteresis, making them unsuitable for accurately matching angular positions and torque levels, especially when forces differ by direction.

Innovation Solution

A force transmission assembly utilizing a ball socket mechanism with ogive-shaped cam paths and a magnetic damping system, which allows for optimized angular movement and reduced friction, enabling precise torque transmission with a compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the length or diameter of the torsion spring is increased to achieve high angular amplitude, then the angular amplitude of the lever is improved, but the size of the transmission assembly is increased

Engineering Contradiction:
Improveangular amplitude of leverVSAvoidsize of transmission assembly
Core Design Contradiction:
Length of moving objectVSVolume of stationary object

Solution Approach 1:

The transmission assembly is divided into modular components: a first element with cam paths, a second element with rollers, and a ball socket mechanism. This segmentation allows each component to be optimized independently, achieving high angular amplitude without proportionally increasing the overall assembly size.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The ball socket mechanism introduces spherical geometry to the transmission system, enabling compact angular movement. The curved cam paths and spherical joint allow for optimized angular amplitude within a reduced spatial envelope compared to linear torsion spring arrangements.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Volume of stationary object

If a clutch mechanism with cams and rollers is used to transmit force, then the transmission assembly can be compact, but friction hysteresis and play reduce measurement precision

Engineering Contradiction:
Improvesize of transmission assemblyVSAvoidprecision of angular position matching
Core Design Contradiction:
Volume of stationary objectVSMeasurement precision

Solution Approach 1:

The ball socket mechanism partially replaces traditional friction-based mechanical connections with a spherical joint system that reduces play and hysteresis. This substitution maintains compact dimensions while improving the precision of angular position transmission.

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

Solution Approach 2:

The cam paths are designed with specific dynamics to minimize friction hysteresis during rotation. The rollers follow optimized trajectories that reduce sliding friction, and the ball socket allows for dynamic adaptation to load variations, maintaining precision across different operating conditions.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If significant angular play is provided in the transfixing pin connection, then the clutch mechanism can accommodate manufacturing tolerances, but the precision of matching lever position with torque is reduced

Engineering Contradiction:
Improvetolerance accommodationVSAvoidprecision of torque-angle matching
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The ball socket acts as an intermediary element between the cam-roller mechanism and the output shaft. It mediates the transmission of motion while compensating for manufacturing tolerances through its spherical geometry, maintaining precision without requiring tight tolerances in the pin connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 assembly achieves reliable and precise displacement laws with reduced size, supporting a wide angular amplitude and minimizing friction hysteresis, enhancing piloting precision and comfort while maintaining a compact form factor.

Implementation Method 1

A force transmission assembly utilizing a ball socket mechanism with ogive-shaped cam paths and a magnetic damping system, which allows for optimized angular movement and reduced friction

Methodology Applied
Scientific EffectFriction reduction through ball socket: Ball Bearing

Implementation Method 2

A force transmission assembly utilizing a ball socket mechanism with ogive-shaped cam paths and a magnetic damping system, which allows for optimized angular movement and reduced friction

Methodology Applied
Scientific EffectMagnetic damping: Magnetic Hysteresis

Data Source

PatentEP2349832B1Force transmission unit and control unit including such a unit
Publication Date: 2013.09.04 FLY BY WIRE SYST FRANCE
  • EP2349832B1 patent drawingFigure 1~7
  • EP2349832B1 patent drawingFigure 2
  • EP2349832B1 patent drawingFigure 3~5

AI summary

The invention relates to a force transmission unit (1), particularly enabling the transmission of forces between a lever and a steering member, including: - a force transmission device (8) comprising a shaft (81) defining a central axis (X-X), and - a force accompanying device (3) comprising: - a cam (71), the shaft and the cam being suitable for being rotatably mobile in relation to one another, - a push member (6) suitable for engaging with the cam and for translating along the shaft, and - and a resilient member (9) suitable for working under compression during a translation movement of the push member (6), said translation movement being caused by activating the transmission unit. The push member (6) includes, at the same time, a body (68) designed for receiving cam followers (621; 622) suitable for engaging with the cam (71), and a linear bearing (64) arranged in the body, the bearing being suitable for engaging with the shaft (81).