Helicopter Trim Actuator Compactness and Maintenance
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Solution Overview
Problem
Existing trim actuators for rotorcraft flight controls lack compactness, robustness, and maintainability, and often have complex kinematic chains that are difficult to maintain and repair.
Innovation Solution
A compact and robust trim actuator design featuring a self-synchronous motor with a rotating cage, a multi-stage speed reducer with parallel gear axes, a torsionally deformable structure for torque sensing, and an electromagnetic clutch or brake system to minimize play and facilitate maintenance, along with magnetic sensors for position feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex kinematic chain with multiple components (irreversible reduction gear, clutch, shock absorber, second reducer, spring box, safety device) is used in the trim actuator, then the actuator can achieve reliable flight control, but the device complexity and difficulty of maintenance increase
Solution Approach 1:
The speed reducer is divided into multiple modules or speed reduction stages, each comprising a pair of gears. This segmentation allows for easier maintenance and repair of individual modules while maintaining overall system reliability.
Solution Approach 2:
The clutch and safety device are extracted as separate, independently controllable components. The clutch can be engaged or disengaged to isolate the motor from the output shaft, and the safety device can be independently activated, simplifying maintenance procedures.
2Ease of manufacture
If traditional trim actuator designs are used, then flight control functionality is achieved, but compactness and ease of manufacture are reduced
Solution Approach 1:
The brake lining is nested within the jack housing, and the electromagnetic inductor is integrated into the housing structure. This nesting approach reduces overall actuator volume while maintaining manufacturing simplicity.
Solution Approach 2:
The brake system and electromagnetic clutch components are merged into a integrated assembly within the jack housing, reducing the number of separate components and simplifying manufacturing processes.
3Measurement precision
If play is present in the kinematic chain, then the actuator structure remains flexible and easy to assemble, but control precision deteriorates
Solution Approach 1:
The brake lining acts as an intermediary element that can be engaged to eliminate play in the kinematic chain. When the electromagnetic inductor engages the brake lining against the rotating cage, it temporarily anchors the rotating cage to the jack housing, minimizing play while maintaining assembly simplicity.
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 results in a trim actuator that is more compact, robust, and easier to maintain, with improved control precision and reliability, allowing for efficient operation and reduced maintenance needs.
Implementation Method 1
a brake lining as well as an electromagnetic inductor capable of engaging or disengaging said braking lining against the rotating cage
Implementation Method 2
an electromagnetic inductor capable of engaging or disengaging said braking lining against the rotating cage
Implementation Method 3
a member/sensor sensitive to the resistive torque transmitted by the output shaft, this member being interposed between - and coupled in rotation with - the output shaft and the speed reducer. This member/sensor comprises a torsionally deformable structure
Implementation Method 4
two sensors sensitive to an angular position which are arranged on either side of the torsionally deformable structure
Implementation Method 5
the two angular position sensors are magnetic sensors and include said first angular position sensor sensitive to the angular position of the output shaft
Data Source
Figure 1
Figure 2
Figure 3~6
AI summary
The cylinder (10) has a reversible speed reducer (13) driven by a rotating electrical autosynchronous motor (11). An output shaft (16) is driven in rotation by the reducer. A control circuit is connected to an angular position sensor e.g. magnetic sensor, and the motor. The circuit delivers a power supply signal for the motor. The signal varies based on a position setpoint signal applied to the circuit and signals from the sensor. The reducer has speed reducing modules/stages, in which each module/stage comprises a pair of gears rotatably mounted along parallel rotation axes (17, 160).