Piston Adjuster Assembly Using a Crushable Body for Brake Wear
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Solution Overview
Problem
The increased wear of friction surfaces in aircraft brake systems leads to a longer stroke length of the piston, resulting in a longer engagement time and requiring periodic manual adjustments to maintain proper clearance between friction surfaces.
Innovation Solution
A piston assembly with an adjuster assembly that includes a crushable body and a piston stroke limiter, where the crushable body reduces in axial length when compressed to maintain the return stroke length, and a retraction biasing member biases the piston to a retracted position, ensuring consistent engagement and disengagement of the brake system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If friction surfaces wear over time, then the clearance between friction surfaces increases, but the stroke length and engagement time increase
Solution Approach 1:
The adjuster assembly automatically compensates for wear in the friction elements by allowing the piston to extend beyond the normal stroke limit, crushing the crushable body to establish a new retracted position, thereby maintaining consistent engagement time and release clearance without manual intervention
Solution Approach 2:
The system changes the physical state of the crushable body from uncompressed to crushed, altering the piston's retracted position parameter to compensate for wear-induced clearance increases, thereby maintaining consistent engagement characteristics
2Reliability
If manual adjustment is performed periodically, then the clearance is maintained, but the system requires停机 and manual intervention
Solution Approach 1:
The adjuster assembly performs automatic compensation for wear by utilizing the piston's own motion during normal operation to crush the adjustable body and reset the stroke length, eliminating the need for manual adjustment operations
Solution Approach 2:
The system prepares for wear compensation in advance by providing an adjustable body that can be crushed when wear reaches a threshold, automatically resetting the piston stroke before performance degradation occurs
3Ease of operation
If automatic adjuster is implemented, then manual adjustment is eliminated, but the device complexity increases
Solution Approach 1:
The automatic adjustment function is extracted as a separate modular adjuster assembly that can be integrated into the piston assembly, allowing the complexity to be isolated and managed independently while providing automatic wear compensation
Solution Approach 2:
The crushable body is designed as a consumable component that is intentionally made simple and inexpensive, replacing complex mechanical adjustment mechanisms with a simple crushable element that is replaced periodically rather than maintained
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 solution automatically compensates for wear in frictional parts by maintaining the release clearance and stroke length, reducing the need for manual adjustments and ensuring consistent braking performance over multiple cycles, thus enhancing the reliability and efficiency of the aircraft brake system.
Implementation Method 1
a crushable body acting between the piston and the piston stroke limiter, the crushable body being arranged to reduce in axial length when a length of an extension stroke exceeds a length of a retraction stroke
Implementation Method 2
a retraction biasing member arranged to bias the piston stroke limiter from an extended position to a retracted position
Data Source
AI summary
The present application relates to a piston assembly for engaging two selectively engageable parts. The piston assembly has a housing defining a piston cylinder and a piston. The assembly also has a piston stroke limiter. The piston stroke limiter is configured to limit the length of a return stroke of the piston from an extended stroke position and a retracted stroke position. A crushable body acts between the piston and the piston stroke limiter and is arranged to reduce in axial length when a length of an extended stroke exceeds a length of a retraction stroke to maintain the length of the return stroke.