Hydraulic Shock Absorber Stroke Limiter Automated Assembly

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Solution Overview

Problem

Conventional hydraulic shock absorbers for vehicle suspension face challenges in automated assembly of stroke limiter components and generate noise due to gaps between parts, affecting passenger comfort and assembly efficiency.

Innovation Solution

A hydraulic stop design featuring a tubular shell, a concentric tubular body, and an axially movable reciprocating rod with an annular elastomeric stroke limiter, comprising a retaining ring, locking ring, and sealing ring, where the retaining ring has elastic projections and a conical recess, allowing for automated assembly and reduced part gaps to minimize noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If conventional hydraulic shock absorbers use multiple component parts for the stroke limiter member, then the damping performance can be maintained, but the automated assembly becomes difficult and the device complexity increases

Engineering Contradiction:
Improveautomated assembly capabilityVSAvoidnumber of component parts
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent combines multiple separate components (retaining ring, locking ring, and sealing ring) into a single integrated elastomeric stroke limiter member with molded-in features. This merging eliminates the need for multiple discrete parts and complex assembly sequences, enabling automated assembly while maintaining the functional requirements of retention, locking, and sealing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention changes the physical state and properties of the stroke limiter from a metallic assembly requiring mechanical fastening to an elastomeric component that can be molded as a single piece. This parameter change in material properties and structural integration enables automated assembly processes while reducing device complexity.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If gaps exist between the stroke limiter member components, then the assembly can accommodate manufacturing tolerances, but noise is generated affecting passenger comfort

Engineering Contradiction:
Improvenoise levelVSAvoidpart fit tolerance
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

By integrating the retaining ring, locking ring, and sealing ring into a single elastomeric component with molded-in features, the invention eliminates gaps between separate metal parts. The integrated design maintains manufacturing tolerance accommodation through elastomeric flexibility while preventing noise-generating gaps between components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The use of elastomeric material for the integrated stroke limiter member provides both the flexibility needed to accommodate manufacturing tolerances and the seamless construction that eliminates noise-generating gaps. The composite nature of the molded-in metal features within the elastomeric body achieves both tolerance accommodation and noise reduction.

Inventive Principle:
Principle #40Composite materials

3Productivity

If a conventional stroke limiter design is used, then the mechanical limiting function is provided, but the assembly requires manual intervention and cannot be automated

Engineering Contradiction:
Improveassembly efficiencyVSAvoidassembly operation complexity
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The integration of retention, locking, and sealing functions into a single elastomeric stroke limiter member with molded-in features creates a unitary component that can be automatically assembled. This merging eliminates the need for manual assembly of multiple parts, enabling automated production lines while maintaining the complete mechanical limiting function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The elastomeric stroke limiter member with molded-in retention and locking features is designed to self-retain and self-lock during automated assembly without requiring additional manual operations. The integrated design allows the component to perform its own retention and locking functions during the assembly process, enabling full automation.

Inventive Principle:
Principle #25Self-service

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 automated and sequential assembly of the hydraulic stop components, reducing noise and improving assembly efficiency, while maintaining effective damping performance and passenger comfort.

Implementation Method 1

a shock absorber for the suspension of a vehicle... containing a viscous fluid... the passage of the viscous fluid through said valve... resistance force to the movement

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Implementation Method 2

the retaining ring has elastic projections and a conical recess, allowing for automated assembly

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2910811B1Hydraulic shock absorber for suspension system and corresponding improved hydraulic stop
Publication Date: 2019.06.26 MAGNETI MARELLI COFAP FABDORA DE PECAS
  • EP2910811B1 patent drawingFigure 1~3
  • EP2910811B1 patent drawingFigure 2

AI summary

It is herein described a shock absorber for suspension system and its improved hydraulic stop, said shock absorber comprising a tubular shell, a tubular body (20) and an axially movable reciprocating rod provided with an annular elastomeric stroke limiter member. Said stroke limiter member (6) comprises a retaining ring (7), a locking ring (8) and a sealing ring (9), said retaining ring (7) partially enclosing said locking ring (8) and defining, together with said locking ring (8), a groove (91) capable of receiving said one seal ring (9).