Brake Actuator Sealing Boot With Fold Eversion for Compact Stroke
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Solution Overview
Problem
Existing brake actuators face issues with sealing boots that consume excessive space within the housing, impair connectivity with the brake mechanism, and have a limited lifespan due to interference with particulate matter and mechanical integrity.
Innovation Solution
The design incorporates a sealing boot with first outer folds that abut against a stop shoulder inside the housing and second outer folds that evert past the shoulder, minimizing space consumption while maintaining mechanical integrity and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sealing boot has a substantial outer diameter in the end portion engaging the push rod aperture to prevent impairment of stroke movement, then the stroke movement is maintained, but the space consumption within the housing increases
Solution Approach 1:
The sealing boot is divided into multiple outer folds (first outer folds and second outer folds) that can deform independently. This segmentation allows the boot to compress axially without requiring excessive radial space, as the folds can collapse and rearrange during push rod movement.
Solution Approach 2:
The sealing boot is designed to dynamically deform between a relaxed state and a loaded state. The outer folds are configured to allow significant axial deformation, enabling the boot to adapt its shape during operation rather than maintaining a fixed substantial outer diameter throughout the stroke.
2Ease of operation
If the sealing boot deforms sufficiently far in the longitudinal direction to prevent impairment of stroke movement, then the stroke movement is maintained, but the space requirement within the housing increases
Solution Approach 1:
The sealing boot is designed to deform primarily in the longitudinal dimension through the action of multiple outer folds, rather than requiring radial space. The folds allow the boot to compress and extend along the length of the push rod, converting what would be radial space requirements into longitudinal deformation.
3Volume of stationary object
If the sealing boot remains completely inside the brake actuator housing to minimize space consumption, then the space requirement is reduced, but the connectivity with the brake mechanism is impaired
Solution Approach 1:
The sealing boot is designed as a flexible membrane structure with multiple outer folds that can deform significantly. This flexibility allows the boot to extend and maintain connectivity with the brake mechanism while still being contained within the housing boundaries, as the thin film can bend and fold rather than requiring rigid extension space.
4Ease of manufacture
If the sealing boot is designed with fewer folds to reduce complexity, then the manufacturing is simplified, but the longevity is reduced due to increased interference with particulate matter
Solution Approach 1:
Different outer folds are assigned different functions: first outer folds are configured to abut against the stop shoulder to provide mechanical support and sealing, while second outer folds are configured to evert and provide flexibility and protection against particulate matter. This local differentiation of qualities allows each fold to perform its specific function optimally.
5Volume of stationary object
If the first outer folds abut against the stop shoulder inside the housing to minimize space consumption, then the space requirement is reduced, but the mechanical integrity may be compromised
Solution Approach 1:
The stop shoulder serves multiple functions simultaneously: it provides a mechanical stop for the first outer folds to abut against (maintaining structural integrity), acts as a sealing surface, and defines the boundary of the housing interior. This merging of functions allows the design to achieve space efficiency without compromising mechanical strength.
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 configuration reduces space requirements within the brake actuator housing, enhances connectivity with the brake mechanism, and extends the sealing boot's longevity by optimizing the movement and distribution of folds.
Implementation Method 1
the boot having a plurality of outer folds distributed along the longitudinal direction wherein the boot is configured to resiliently deform between a relaxed state and a loaded state
Data Source
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AI summary
The invention relates to a brake actuator (1) for a vehicle, in particular for a commercial vehicle, comprising a housing (3) having a push rod aperture (5), a push rod (7) configured to connect to a brake mechanism (101). The push rod (7) is configured to move back and forth through the push rod aperture (5) between a retracted position and an extended position. A sealing boot (13) extends along the push rod, being flexible in a longitudinal direction (L) and having a first end portion (15) sealingly engaging the push rod (7) at an intermediate region (8) of the push rod (7), and a second end portion (17) sealingly engaging the push-rod aperture (5). The boot (13) has a plurality of outer folds (19a, 19b, 21) distributed along the longitudinal direction (L). The boot (13) is configured to resiliently deform between a relaxed state and a loaded state, the relaxed state corresponding to the retracted position of the push rod (7) and the loaded state corresponding to the extended position of the push rod (7). It is suggested that the first end portion (15) of the boot (13) comprises a stop shoulder (27) arranged inside the housing (3). The plurality of outer folds (19a, 19b, 21) comprises at least one first outer fold (19a, 19b) configured to abut against the stop shoulder (27) inside the housing (3) when the push rod (7) is in the extended position, and at least one second outer fold (21) configured to evert past the stop shoulder (27) to the outside of the housing (3) when the push rod (7) is in the extended position.