Segmented Piston Assembly for High-Load Low-Friction Actuation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aircraft thrust reverser actuation systems face challenges in meeting increasing loads while maintaining synchronization and reducing friction, as traditional designs are costly and difficult to manufacture, and may suffer damage from sudden aerodynamic forces during deployment.
Innovation Solution
A three-piece piston assembly with a bushing, lock nut, and lead screw, where each component can be made from different materials optimized for strength, friction reduction, and wear resistance, and a hydraulic valve controls fluid flow to resist aerodynamic loads during actuator deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional locking actuators use a lead screw nut with radially interior threads to engage the lead screw, then high strength and synchronization are achieved, but the locking feature machined into the piston is difficult to manufacture and leads to higher costs
Solution Approach 1:
The piston is divided into multiple segments: a piston body, a separate lock nut, and a locking feature. This segmentation allows the locking feature to be added as a separate component rather than being machined directly into the piston, significantly reducing manufacturing complexity while maintaining the required load holding capability through the dedicated lock nut design
Solution Approach 2:
A separate lock nut is introduced as an intermediary component between the lead screw and the piston locking feature. This lock nut engages with both the lead screw threads and the piston locking feature, distributing loads and simplifying the manufacturing of each individual component while maintaining the overall strength and synchronization requirements
2Force
If aircraft loads are increased to meet new design requirements, then load capability is improved, but friction and wear in the lead screw nut assembly increase
Solution Approach 1:
The lead screw nut is designed with modified geometric parameters including optimized thread profiles, increased contact surface area, and adjusted clearance tolerances. These parameter changes allow the assembly to handle increased aircraft loads while distributing contact pressures more evenly, thereby reducing friction and wear compared to traditional designs
3Stability of the object's composition
If a lock key groove is machined into the piston to mechanically lock the actuator, then synchronization is maintained, but manufacturing difficulty and cost increase
Solution Approach 1:
The locking mechanism is segmented into a separate lock nut component rather than being integrated into the piston body. This separate lock nut can be manufactured independently with standard machining processes and then assembled to the piston, maintaining the mechanical locking function for synchronization while significantly reducing the overall manufacturing cost and complexity
Solution Approach 2:
The lock nut is pre-manufactured with the necessary locking features and thread profiles before final assembly to the piston. This preliminary manufacturing of the lock nut as a separate component allows for optimized production processes and quality control, reducing the manufacturing burden on the piston itself while ensuring proper synchronization locking
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 three-piece piston assembly provides improved load capability, reduced friction, and cost-effective manufacturing, while the hydraulic valve mitigates damage from sudden aerodynamic forces, enhancing the reliability and efficiency of thrust reverser actuation systems.
Implementation Method 1
a lead screw arranged within the cylindrical cavity. The lead screw can include a helical lead screw thread arranged to engage a helical bushing thread defined upon a tubular inner surface of the bushing
Implementation Method 2
a hydraulic valve controls fluid flow to resist aerodynamic loads during actuator deployment
Implementation Method 3
a bushing configured to contact the piston inner surface
Implementation Method 4
each component can be made from different materials optimized for strength, friction reduction, and wear resistance
Data Source
AI summary
The subject matter of this specification can be embodied in, among other things, an assembly that includes a piston having a piston inner surface defining a cylindrical cavity and includes a first axial portion, a piston face at a first end of the first axial portion, a second axial portion at a second end of the first axial portion, and a helical piston thread defined upon the piston inner surface, a bushing configured to contact the piston inner surface, and a lock nut configured to engage the piston and the bushing.