Servomotor Sealing Ring Reinforcement for Pressure Leakage

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Solution Overview

Problem

The existing pneumatic brake boosters with inclined annular parts face sealing issues due to high radial pressure differences, leading to potential detachment of the sealing ring and leakage between the front and rear chambers.

Innovation Solution

Incorporating a tubular element in the inclined annular part of the cup to ensure uniform pressure distribution and limit deformations of the sealing ring, with the tubular element being integral or nested within the cup, and the sealing ring being made in one piece with the membrane to enhance sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a sealing ring is used in the inclined annular part of the movable wall, then the booster achieves compactness and rigidity, but the sealing ring is subjected to high radial pressure differences causing local detachment and sealing problems

Engineering Contradiction:
Improverigidity of movable wallVSAvoidsealing performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent introduces a reinforcing element with a specific geometry (protruding into the inclined annular part) that locally enhances the structural properties where needed. This reinforcement is positioned specifically to counteract the high radial pressure differences in the inclined region, providing localized strength support to prevent sealing ring detachment while maintaining the overall compact design

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The reinforcing element is designed to preemptively counteract the detrimental effects of pressure differences before they can cause sealing ring detachment. By having this structural reinforcement in place beforehand, the system prepares for and mitigates the high radial pressure stresses that would otherwise lead to sealing failures

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If the sealing ring is made in one piece with the sealing membrane, then the sealing performance is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvesealing performanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the sealing ring and sealing membrane into a single integrated component. This merging eliminates potential leakage paths between separate components and ensures continuous sealing, directly improving reliability. The integrated design maintains manufacturability through conventional processes while achieving superior sealing performance

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP1870306B1Servomotor with support struts comprising reinforced sealing rings
Publication Date: 2017.09.06 ROBERT BOSCH GMBH
  • EP1870306B1 patent drawingFigure 1
  • EP1870306B1 patent drawingFigure 2~3

AI summary

The actuator has a transversal partition (14) movably mounted inside a rigid envelope (12). The partition delimits a sealed front and rear chamber (16, 18) subjected to respective pressures (P1, P2), and has a mount (38) covered with a sealed membrane (42) connected to an inner periphery of the envelope. The mount has a tubular element (50) with a boring (46) associated to each of tie rods (24). Each rod receives a seal ring (48) fixed to the mount and slidably mounted on the associated tie rod. The tubular element is axially extended around the seal ring.