Brake Actuator Piston Adjuster Assembly for Clearance Compensation
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Solution Overview
Problem
Aircraft brake systems face wear-induced increases in actuator piston standoff distance due to friction stack wear, leading to undesired clearance changes during repeated braking cycles, which affects braking performance.
Innovation Solution
A brake actuator assembly featuring a deformable member and a resilient member, coupled via a thrust washer, that undergoes permanent deformation when brake pressure is applied, maintaining a consistent actuator piston clearance by radially positioning the deformable member between the piston rod and housing, utilizing materials like steel, stainless steel, or ceramic, and configured to absorb wear-related changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional brake actuator is used without a deformable member, then the structure is simple, but the actuator piston clearance increases due to friction stack wear
Solution Approach 1:
The deformable member changes its physical state from elastic to plastic deformation under brake pressure, allowing it to permanently adjust and compensate for friction stack wear. This parameter change enables the system to maintain consistent piston clearance without complex adjustment mechanisms.
Solution Approach 2:
The deformable member automatically compensates for friction stack wear through its own deformation characteristics, eliminating the need for external adjustment mechanisms or complex control systems. The member self-regulates the piston clearance based on the wear conditions.
2Manufacturing precision
If a deformable member is added to maintain piston clearance, then braking performance consistency is improved, but manufacturing complexity increases
Solution Approach 1:
The deformable member is designed to undergo controlled plastic deformation at specific stress thresholds, transforming the manufacturing challenge into a material selection and geometric design problem rather than a complex assembly problem.
Solution Approach 2:
The brake actuator employs composite construction combining a resilient member (elastic material) and a deformable member (plastic-deforming material), leveraging the complementary properties of different materials to achieve both precision and manufacturability.
3Reliability
If the deformable member undergoes permanent deformation, then wear compensation is achieved, but the member's structural integrity may be compromised
Solution Approach 1:
The deformable member is designed with non-uniform geometry, featuring a thinner wall section specifically positioned to undergo plastic deformation while thicker sections maintain structural integrity. This local quality variation allows controlled deformation without compromising overall strength.
Solution Approach 2:
The deformable member is pre-designed with predetermined deformation characteristics through its geometric configuration, allowing it to automatically compensate for expected wear ranges before actual wear occurs, ensuring both wear compensation and structural integrity.
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 maintains the desired actuator piston clearance, ensuring consistent braking performance and reducing wear-related issues by allowing the deformable member to permanently deform in response to brake pressure, thus compensating for friction stack wear over repeated cycles.
Implementation Method 1
a resilient member disposed within the housing and coupled to the piston
Implementation Method 2
the deformable member is configured to undergo a permanent deformation in response to applying a brake pressure to the piston
Data Source
AI summary
A brake actuator assembly may comprise a housing, a piston disposed in the housing and slidably engaged therewith, a resilient member disposed within the housing and coupled to the piston, and a deformable member disposed within the housing a coupled to the piston, wherein each of the deformable member and the resilient member are disposed radially between a piston rod of the piston and the housing.