Jam-Tolerant Linear Control Motor for Hydraulic Actuator

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Solution Overview

Problem

Rotorcraft control motors are prone to magnetic seizing and bearing failures, which can lead to catastrophic failures of actuators and hydraulic systems, especially in systems with limited redundancy, posing a significant risk to flight safety.

Innovation Solution

The development of a jam-tolerant linear control motor design that incorporates non-magnetic materials to prevent magnetic seizing and includes features such as break wires to detect bearing failures, allowing for early detection and prevention of failures before they become catastrophic, and mechanisms to reduce failures in joints that convert rotary motion into linear motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If magnetic components are used in the control motor, then the motor can generate sufficient force to actuate the hydraulic valve, but magnetic seizing occurs leading to catastrophic failure

Engineering Contradiction:

Improvemotor forceVSAvoidfailure risk

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The patent removes magnetic components from the control motor design, extracting the source of magnetic seizing while maintaining motor functionality through alternative non-magnetic actuation mechanisms. This eliminates the harmful magnetic interactions that caused seizing between rotor and stator components.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces non-magnetic intermediary materials and designs between moving components, using materials such as non-magnetic metals or composites that mediate the interaction between rotor and stator, preventing direct magnetic contact while still allowing force transmission.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If traditional bearing designs are used in the control motor, then the motor can operate smoothly, but bearing failures occur without early detection leading to catastrophic failure

Engineering Contradiction:

Improvemotor operationVSAvoidfailure detection

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent incorporates feedback mechanisms including break wires and sensors that continuously monitor bearing condition and provide real-time information about motor operation, enabling detection of bearing degradation and failure modes before they lead to catastrophic system failure.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent implements preliminary detection features such as break wires positioned to detect bearing failure early in the failure process, allowing preventive action to be taken before the bearing failure propagates to other critical components.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If joints converting rotary motion to linear motion are used in the actuator, then the hydraulic valve can be actuated, but joint failures occur leading to loss of actuator function

Engineering Contradiction:

Improvemotion conversionVSAvoidjoint failure

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces traditional mechanical joints that convert rotary to linear motion with alternative mechanisms such as bellcranks or direct-coupled linear actuators, eliminating the joint interfaces that are prone to failure while maintaining the necessary motion conversion functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Device complexity

If redundant systems are not implemented in the control system, then the system complexity is reduced, but the system is highly vulnerable to single-point failures

Engineering Contradiction:

Improvesystem complexityVSAvoidsystem vulnerability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent implements beforehand cushioning through detection and warning systems that prepare the operator for potential failures, allowing preventive maintenance or graceful degradation before catastrophic failure occurs, effectively cushioning against the impact of single-point failures.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 effectively reduces the occurrence of magnetic seizing and bearing failures, enhancing the reliability of rotorcraft control systems by enabling early detection and maintenance, thereby improving flight safety and reducing the likelihood of system failures.

Implementation Method 1

a coil wrapped around the armature and operable to selectively add and subtract magnetic flux from the magnetic flux path

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a non-magnetic material disposed between the coil and the magnet and magnetic material

Methodology Applied

Scientific EffectMagnetic flux containment: Magnetic Field

Data Source

PatentUS9889929B2Jam-tolerant linear control motor for hydraulic actuator valve

Publication Date: 2018.02.13 BELL HELICOPTER TEXTRON INC

AI summary

According to one embodiment, a linear control motor includes a first permanent magnet, a coil, a first magnetic material, a shaft, and a first non-magnetic material. The first non-magnetic material is disposed between at least one of the movable components and at least one of the static components and operable to prevent physical contact between at least one of the movable components and at least one of the static components.