Shock Absorber Sealing Assembly Low-Temperature Performance
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Solution Overview
Problem
Existing guiding and sealing units for mono-tube shock absorbers are complex, cumbersome to mount, and perform poorly at low temperatures, with limitations in withstanding high pressures and maintaining efficiency over time, especially at temperatures below -15°C.
Innovation Solution
A guiding and sealing unit with a novel sealing assembly featuring a reinforcing structure made of a low-friction, rigid material and an elastomeric sealing ring, designed to withstand extreme temperatures (-40°C to 200°C), reducing axial dimensions, and incorporating a reinforcing ring and sleeve-shaped portion to distribute stress and enhance sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional sealing assembly with multiple separate elements is used, then sealing function is provided, but the assembly becomes complex and cumbersome to mount
Solution Approach 1:
The patent combines multiple separate sealing elements (sealing ring, guiding elements, backup rings) into a single integrated sealing assembly that is pre-mounted on the rod. This integration eliminates the need for complex step-by-step assembly of multiple components during installation, directly resolving the contradiction between providing comprehensive sealing function and maintaining assembly simplicity.
2Reliability
If FKM elastomeric material is used for the sealing ring, then good sealing performance is achieved, but the minimum working temperature is limited to -15°C
Solution Approach 1:
The patent employs a composite sealing assembly structure combining FKM elastomeric sealing ring with PTFE (polytetrafluoroethylene) guiding elements and reinforcement structures. The PTFE component, with its superior low-temperature performance and low friction characteristics, compensates for the FKM material's temperature limitation, enabling the assembly to function reliably at temperatures as low as -40°C while maintaining sealing effectiveness.
3Reliability
If the sealing assembly is designed with larger axial bulk, then durability and sealing performance are improved, but the overall dimensions and weight of the shock absorber increase
Solution Approach 1:
The sealing assembly incorporates dynamic geometric features including conical surfaces and angled contact surfaces that allow the sealing elements to deform and adapt under pressure. This dynamic design enables the sealing lip to maintain optimal contact pressure with the rod surface during reciprocating motion, improving sealing durability and wear resistance without requiring excessive axial length.
Solution Approach 2:
The patent optimizes geometric parameters such as the cone angle of the sealing surface, the thickness distribution of the sealing ring, and the positioning of reinforcement structures. By carefully selecting these parameters, the design achieves maximum sealing effectiveness and durability within a minimized axial envelope, preventing unnecessary increase in shock absorber dimensions and weight.
4Adaptability or versatility
If the sealing lip deforms excessively in radial direction, then sealing adaptation improves, but performance decays at low temperatures and under high pressure
Solution Approach 1:
The sealing assembly features non-uniform radial thickness distribution and localized reinforcement structures positioned strategically around the sealing lip. These local quality variations provide enhanced structural support in critical areas while allowing controlled deformation in other regions, enabling the sealing lip to adapt to rod surface irregularities without excessive overall deformation that would compromise low-temperature performance.
Solution Approach 2:
The sealing lip incorporates curved and conical geometric profiles rather than straight cylindrical forms. These curved geometries provide gradual stress distribution and controlled elastic deformation characteristics, allowing the sealing surface to conform to the rod while maintaining structural integrity under high pressure and low temperature conditions.
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
The solution provides improved sealing performance and durability at low temperatures, reduces the overall dimensions and weight of the shock absorber, and simplifies assembly, achieving efficient hydraulic sealing and reducing friction and wear, while maintaining effective operation across a wide temperature range.
Implementation Method 1
a sealing ring (12) made of an elastomeric material and having an annular sealing lip (13), which radially and axially protrudes within the cup-shaped seat (9) to slidingly cooperate with the rod (2)
Implementation Method 2
The particular geometry of the sealing assembly and of the respective guiding unit according to the invention allows to limit in use the maximum deformation in radial direction of the sealing lip thus also obtaining a synergic effect which allows, on one hand, to avoid the known performance decay in response to a temperature decrease
Implementation Method 3
The reinforcing ring (18) is made of a low friction coefficient material
Data Source
Figure 1
Figure 2~3
AI summary
A guiding and sealing unit (1) for a rod (2) of a shock absorber, including a bush (6), which is fluid-tightly fixed in use to an inner lateral wall (5) of shock absorber body (4) and a sealing assembly (8) driven into a cup-shaped seat on one end of the bush (6) facing the inside of the shock absorber body; the sealing assembly includes a sealing ring (12) made of elastomeric material and having an annular sealing lip (13), which radially and axially protrudes within the cup-shaped seat (9) to cooperate in contact with the rod in use, a metallic reinforcing structure (14), having a flange-shaped portion (15), arranged abuttingly against the end of the bush and a sleeve-shaped portion (16), which obliquely protrudes within the cup-shaped seat, in direction opposite to that of the annular lip, embedded in the sealing ring so as to at least partially flank the lip (13) on the side of a root portion (17) thereof; and a reinforcing ring (18) snappingly mounted on the sealing ring (12) on side opposite to the lip, engaged in use on the rod, made of low friction coefficient material more rigid than the material of the sealing ring and which axially extends in the seat flanking at least in part the sleeve-like portion (16) of the reinforcing structure.