Aircraft Brake Actuator Sleeve Guide Prevents Wear Scratches
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Solution Overview
Problem
Aircraft wheel hydraulic brake actuators face issues with wear take-up devices causing undesirable scratches on central rods due to tilting of the movable stop, leading to deterioration of the seal and leakage.
Innovation Solution
The proximal end of the sleeve is radially widened to fit against the internal face of the internal cage, preventing tilting and guiding the sleeve, while an elastic member returns the piston to a retracted position, maintaining contact with the internal cage to avoid scratches and ensure proper sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the movable stop is equipped with a radially deformable sleeve that cooperates with an olive to be deformed, then the wear take-up device can compensate for friction element wear, but the sleeve tends to tilt around the olive causing scratches on the central rod
Solution Approach 1:
A guide element is introduced as an intermediary component between the sleeve and the central rod. This guide element prevents the sleeve from tilting by providing a guiding surface that constrains the sleeve's movement, thereby eliminating the harmful scratches on the central rod while preserving the wear compensation function
Solution Approach 2:
The guide element adds a new dimensional constraint by extending radially outward to contact the sleeve's outer surface. This creates a new degree of freedom control in the radial direction, preventing tilting motion around the olive while allowing axial movement for wear compensation
2Ease of operation
If the proximal end of the piston is guided by the central rod with a seal extending between them, then the piston can slide along the sliding axis, but scratches on the rod cause deterioration of the seal and loss of tightness
Solution Approach 1:
The guide element serves as a protective intermediary that intercepts the tilting motion before it can transfer to the central rod. By preventing scratches on the rod, the guide element indirectly protects the seal from deterioration, maintaining seal tightness while preserving piston sliding functionality
Solution Approach 2:
The guide element provides preemptive protection by preventing the formation of scratches on the central rod before the seal can be damaged. This anticipatory measure eliminates the root cause of seal deterioration, ensuring long-term reliability
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 design prevents the formation of scratches on the wear take-up device, maintaining the tightness of the actuator and ensuring reliable operation by guiding the sleeve and maintaining contact with the internal cage, thus enhancing the longevity and performance of the brake actuator.
Implementation Method 1
an elastic member for returning the piston to the retracted position defined by pressing the piston against the inner cage
Implementation Method 2
the movable abutment comprises a radially deformable sleeve which cooperates with an olive, to be deformed by said olive, which is secured to a distal end the fixed part of the wear take-up device
Implementation Method 3
a wear take-up device which defines, with the internal cage, a retracted position of the piston in the liner by means of an axially movable stop that can be advanced by the internal cage when a braking force is applied and in frictional relation with a fixed part of the wear take-up device
Data Source
Figure 1~4
Figure 2~3
AI summary
The invention relates to a brake actuator comprising a sleeve (1), a piston (3) mounted to slide sealed in the sleeve to apply a braking force, the piston being equipped with an internal cage (21), a wear compensation device (10) which defines a retraction position of the piston in the sleeve by means of an axially movable stop which can be advanced by the piston when a braking force is applied and in frictional relationship with a fixed part (12) of the wear compensation device integral with the sleeve, the movable stop comprising a radially deformable bushing (16) which cooperates with an olive (15) integral with a distal end of the fixed part of the wear compensation device, the bushing being deformed at its proximal end (17) towards an internal face of the internal cage (21).