Integrated Sealing Assembly for Mono-Tube Shock Absorber Rods

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Solution Overview

Problem

Existing guiding and sealing units for mono-tube shock absorbers are cumbersome and complex to assemble, particularly due to the separate components required for the limit stop element, which increases dimensions and weight, and are costly to produce.

Innovation Solution

An integrated sealing assembly that combines the traditional limit stop element with the static seal and dynamic sealing lip, using higher-quality material for the sealing lip and more common, cost-effective material for other components, reducing axial dimensions and weight while maintaining performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate components are used for limit stop element, static seal, and dynamic sealing lip, then each component can be optimized independently, but the assembly becomes cumbersome and complex, increasing dimensions and weight

Engineering Contradiction:
Improvecomponent optimizationVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the limit stop element, static seal, and dynamic sealing lip into a single integrated sealing assembly. The sealing assembly includes a first sealing portion for dynamic sealing of the rod, a second sealing portion for static sealing at the bush interface, and a limit stop portion integrated into the same component structure, eliminating the need for separate assembly operations and reducing overall complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated sealing assembly performs multiple functions simultaneously: it provides dynamic sealing of the rod, static sealing at the bush connection, and limit stopping for the piston. This multi-functional design reduces the number of separate components needed while maintaining independent optimization of each sealing function through specialized material selection for different portions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If separate components are used for limit stop element, static seal, and dynamic sealing lip, then each component can be optimized independently, but the axial dimensions and weight of the shock absorber increase

Engineering Contradiction:
Improvecomponent optimizationVSAvoidaxial dimensions
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent combines the limit stop element, static seal, and dynamic sealing lip into a single integrated sealing assembly. The sealing assembly includes a first sealing portion for dynamic sealing of the rod, a second sealing portion for static sealing at the bush interface, and a limit stop portion integrated into the same component structure, eliminating the need for separate assembly operations and reducing overall complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated sealing assembly is designed to fit within the existing bush structure, with the limit stop portion and sealing portions nested within the same axial space. This nesting approach allows multiple functions to be achieved within compact dimensions without requiring additional axial length for separate components.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Reliability

If high performance elastomeric material is used for the entire sealing assembly including static seal, then sealing performance is improved, but production cost increases

Engineering Contradiction:
Improvesealing performanceVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies different material qualities to different portions of the sealing assembly based on their specific functional requirements. The first sealing portion that contacts the rod uses high-performance elastomeric material for optimal dynamic sealing, while the second sealing portion for static sealing uses a more common, cost-effective material, thereby reducing overall production costs while maintaining necessary sealing performance at each location.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The integrated sealing assembly is constructed as a composite structure with different material compositions for different portions. This allows optimization of material selection for each specific sealing function - high-performance elastomers where needed for dynamic sealing and more economical materials for static sealing applications - resulting in a cost-effective composite solution that maintains overall sealing reliability.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2418393B1Guiding and sealing unit, in particular for a rod of mono-tube shock absorber and annular sealing assembly therefor
Publication Date: 2014.10.15 AB SKF SKF PATENT DEPARTMENT
  • EP2418393B1 patent drawingFigure 1
  • EP2418393B1 patent drawingFigure 2
  • EP2418393B1 patent drawingFigure 3

AI summary

A guiding and sealing unit (1) for a shock absorber rod (2) including a bush (7) and a sealing assembly (8), integrally carried by an end of the bush (7) facing the piston of the shock absorber in use, and including a sealing ring (12) made of elastomeric material having at least one annular sealing lip (13) which radially and overhangingly protrudes towards a symmetry axis thereof to cooperate in use with the rod, and a metallic reinforcing structure (14), having a flange-shaped portion (15) abuttingly arranged against the end of the bush and a sleeve-shaped portion (16) operatively associated to the sealing lip; the sealing ring has a flange-shaped portion (18) which radially extends from a root portion (19) of the at least one annular lip, and an annular projection (20) integrally obtained in one piece with the flange-shaped portion (18), which axially and protrudingly extends from the latter, from the side facing the piston (5) in use and shaped so as to make, in use, a limit stop element for the piston (5); the flange-shaped portion of the reinforcing structure (15) is coupled to the flange-shaped portion of the sealing ring (18) and extends under the annular projection (20).