Cover-to-Housing Ring Lock for High-Force Hydraulic Retention

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Solution Overview

Problem

Existing fastening methods for hydraulic components, such as those in brake pressure control systems, face challenges in securely attaching covers to housings without requiring excessive forming force, especially for larger diameters, and ensuring mechanical stability against high release forces.

Innovation Solution

A combination of a cover and a housing featuring a connecting ring that engages with circumferential grooves on both the cover and the housing, with obliquely angled groove flanks that radially expand and contract to secure the cover, preventing removal without damage, and a sealing ring for added sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a clamping ring made of soft, elastic rubber is used with an interference fit between the collar and container opening, then the lid can be firmly connected to the container, but the collar requires significant outward force to generate sufficient clamping force and the connection becomes irreversible without destruction

Engineering Contradiction:
Improveclamping forceVSAvoidease of attachment and detachment
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The connecting ring is designed with dynamic properties - it can be elastically deformed during insertion to pass through the cover, then automatically expands to engage with the groove flanks. The oblique groove flanks convert axial insertion force into radial clamping force dynamically, allowing the ring to adapt its clamping force based on insertion depth and pressure conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The connection mechanism is segmented into distinct functional elements: the connecting ring as a separate elastic component, the oblique groove flanks as force transformation surfaces, and the grooves as engagement features. This segmentation allows each element to perform its specific function optimally - the ring provides elasticity, the flanks provide force transformation, and the grooves provide positioning.

Inventive Principle:
Principle #1Segmentation

2Reliability

If conventional fastening methods are used for hydraulic components with larger diameters, then the cover can be attached to the housing, but excessive forming force is required and mechanical stability against high release forces is compromised

Engineering Contradiction:
Improvemechanical stabilityVSAvoidforming force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The connecting ring utilizes curved elastic deformation to achieve engagement. The ring's circular geometry allows it to be compressed radially during insertion and then expand to contact the groove flanks. The oblique groove flanks convert axial motion into radial expansion, utilizing the ring's elastic curvature properties to generate high clamping forces without requiring excessive forming force during assembly.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The groove flanks are designed with specific oblique angles that change the force parameters during insertion. As the connecting ring is inserted axially, the oblique flanks transform this axial force into radial expansion force, changing the force direction and magnitude to optimally engage the ring with the groove, thereby reducing the required forming force while maintaining high mechanical stability.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the groove flanks run perpendicular to the insertion direction, then the connecting ring can be easily inserted, but the cover cannot resist high release forces and axial play occurs

Engineering Contradiction:
Improveease of insertionVSAvoidresistance to release forces
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The oblique groove flanks create a curved force transformation path. During insertion, the connecting ring follows this oblique path, which gradually transforms axial insertion force into radial clamping force. This curved engagement path allows easy insertion while simultaneously generating the radial forces needed to resist high release forces and eliminate axial play.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The oblique groove flanks create a dynamic force transformation mechanism. As the connecting ring is inserted, the angle of engagement changes continuously along the oblique flank, dynamically converting axial motion into radial clamping force. This dynamic process allows the system to achieve both easy insertion and high resistance to release forces, as the clamping force builds progressively during insertion rather than requiring high initial force.

Inventive Principle:
Principle #15Dynamics

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

Enables quick and easy attachment of the cover to the housing with high mechanical stability, resisting high release forces and ensuring secure fastening without axial play, even under varying diameter tolerances.

Implementation Method 1

A radially resilient connecting ring (14) is inserted into the groove (12). This connecting ring (14) engages in the groove (11) of the cover (7) and in the groove (12) in the inner circumferential wall (13) of the receptacle (8)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a front groove flank (15) of the groove (11) of the cover (7) and a rear groove flank (16) of the groove (12) in the inner circumferential wall (13) of the receptacle (8) for the cover (7) run obliquely from the inside to the outside in the direction of insertion

Methodology Applied
Scientific EffectMechanical Force Transformation: Mechanical Force

Data Source

PatentEP3821157B1Combination of a cover and a housing
Publication Date: 2024.12.11 ROBERT BOSCH GMBH
  • EP3821157B1 patent drawingFigure 1~2
  • EP3821157B1 patent drawingFigure 3~4
  • EP3821157B1 patent drawingFigure 5

AI summary

The invention proposes fastening a cup-shaped cover (7), for example of a pedal travel simulator, hydraulic accumulator or of a damper chamber, by means of a radially resilient connecting ring (14), which projects into a groove (11) of the cover (7) and into an opposite groove (12) of a receptacle (8) of a hydraulic block (1) of a slip controller of a hydraulic vehicle brake system, non-detachably to the hydraulic block (1).