Pneumatic Brake Booster Sealing Element Design
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Solution Overview
Problem
Existing pneumatic brake boosters face challenges in ensuring a reliable seal and easy assembly, as well as preventing damage to the sealing element and corrosion, due to complex multi-stage connections and sharp edges.
Innovation Solution
The design incorporates positive locking portions and axially extending bending tabs to securely connect shell elements, with a conical annular gap to prevent sealing bead slippage and distribute load uniformly, ensuring a reliable seal and corrosion protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-stage cascade of radial shoulders and collars is used to connect shell elements, then the connection reliability is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The connection structure is divided into distinct functional elements: a simplified radial shoulder for positioning and a separate axial collar for securing. This segmentation allows each element to perform its specific function efficiently without the complexity of a multi-stage cascade structure.
Solution Approach 2:
The connection mechanism transitions from radial-only engagement to a combination of radial positioning (shoulder) and axial securing (collar). This dimensional change enables a more straightforward connection approach that reduces structural complexity while maintaining reliability.
2Reliability
If punched-out holding claws are used to fix shell elements, then the assembly is secured, but the corrosion prevention layer is damaged
Solution Approach 1:
The collar acts as an intermediary element that secures the assembly through friction and mechanical engagement without requiring punched holes. This intermediary approach maintains the integrity of the corrosion prevention layer while achieving secure assembly fixation.
Solution Approach 2:
The punched-hole mechanical fastening system is replaced with a friction-based collar retention system. This substitution eliminates the need for holes that would compromise the corrosion prevention layer while maintaining assembly security through alternative mechanical means.
3Reliability
If the sealing bead is clamped in a narrow clamping space, then the sealing reliability is improved, but the risk of sealing bead slippage and detachment increases
Solution Approach 1:
The sealing assembly combines the sealing bead (elastomeric material) with the rigid collar structure. This composite arrangement allows the soft sealing bead to conform to surfaces for reliable sealing while the rigid collar provides the structural strength to prevent slippage and detachment.
Solution Approach 2:
The collar features a curved, annular geometry that conforms to the cylindrical shape of the sealing bead. This curved design distributes clamping forces uniformly around the sealing bead, preventing localized stress concentrations that could lead to slippage or detachment while maintaining effective sealing.
Data Source
AI summary
A pneumatic brake booster having a booster housing. The booster housing has at least two thin-walled shell elements and an elastomer sealing element. The sealing element has a sealing bead, which is of encircling form radially at the outside, and at least one rolling diaphragm portion which adjoins the sealing bead. The sealing bead is sealingly clamped in a clamping space between the shell elements. The clamping space is formed by walls which are generated in the shell elements by deformation, its radial inner wall formed by a tubular, axially forwardly extending projection, which is folded at its front edge, of the second shell element. It is proposed that a bead-side rear wall of the clamping space is formed by an encircling, radially outwardly projecting collar which is formed on the second shell element.