Hydraulic Cable Stop Vibration Damper Sealing Design
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Solution Overview
Problem
The manufacturing and assembly costs of hydraulic tension stops for vibration dampers in motor vehicle wheel suspensions are high due to complex designs requiring multiple components and time-consuming production processes.
Innovation Solution
A vibration damper with a hydraulic cable stop featuring a damping piston with a circumferential groove and a slotted sealing ring that provides a defined permeability and adjustable leakage, allowing for simplified production and assembly without additional leakage grooves or bores, and using a sealing ring made of spring steel or wire with oblique end sections for enhanced sealing and ease of assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex hydraulic cable stop design with multiple components is used, then sealing performance is improved, but manufacturing and assembly costs increase
Solution Approach 1:
The patent combines multiple sealing functions into a single integrated damping piston component. The damping piston includes a circumferential groove with flanks that directly provide sealing surfaces, eliminating the need for separate sealing elements. This merging of functions reduces component count while maintaining sealing effectiveness through the groove geometry and hydraulic pressure-driven sealing mechanism.
Solution Approach 2:
The damping piston serves multiple functions: it provides damping force through hydraulic resistance, creates sealing surfaces through its groove structure, and enables controlled leakage through the slot in the sealing ring. The groove flanks act as both structural elements and sealing surfaces, demonstrating multi-functionality that reduces overall system complexity.
2Reliability
If traditional sealing ring designs are used, then sealing is achieved, but production time increases due to time-consuming assembly processes
Solution Approach 1:
The sealing ring is segmented with a slot that allows it to be compressed radially inward during assembly, enabling easy installation into the circumferential groove. This segmentation facilitates quick assembly while the radial compression mechanism ensures proper sealing contact with the groove flanks during operation.
Solution Approach 2:
The groove flanks are pre-configured with specific geometries that guide the sealing ring into proper position during assembly. The flanks delimit the groove in a way that automatically aligns the sealing ring, eliminating the need for complex alignment procedures and reducing assembly time.
3Reliability
If an annular groove is used in the piston rod, then sealing is achieved, but the piston rod becomes heavier due to solid material requirements
Solution Approach 1:
The invention uses hydraulic pressure to enhance sealing. The groove flanks are designed to be pressed against by hydraulic pressure during operation, creating effective sealing without requiring the piston rod to be made of solid material with an annular groove. This hydraulic sealing mechanism reduces weight while maintaining sealing reliability.
4Reliability
If passage openings are specially produced in the damping piston, then hydraulic damping is achieved, but manufacturing time increases
Solution Approach 1:
The slot in the sealing ring is designed to be dynamically opened or closed based on radial movement. During normal operation, the slot allows hydraulic medium to pass through for damping. When radial compression occurs, the slot closes to provide sealing. This dynamic behavior eliminates the need for specially produced passage openings while maintaining hydraulic damping functionality.
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
This design reduces manufacturing and assembly costs while maintaining effective sealing and hydraulic damping performance, offering a more efficient and cost-effective solution for vibration dampers.
Implementation Method 1
the sealing ring hydraulically seals in said end region of the piston rod extension path in the groove when the piston rod moves in the tension direction
Implementation Method 2
at least locally stands out in order to achieve a defined permeability for a hydraulic damping medium between the groove and the sealing ring
Implementation Method 3
When entering a section with a reduced diameter in the rebound stage, the sealing ring is compressed radially inward in order to close overflow channels formed in the damping piston
Implementation Method 4
A desired seal can be achieved in the rebound stage, with the extent of the slight leakage that is nevertheless desired being adjustable via the gap. When deflecting, a larger overflow cross section is available. The projections prevent an undesired tighter seal. In addition, a defined spring effect in the direction of the width of the groove can be achieved due to their inclined position
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A vibration damper with hydraulic pull-stop for a motor vehicle wheel suspension comprises a reservoir tube (2'''), a piston rod (3''') and a hydraulic damping device (10''') with a damping piston (11''') attached to the piston rod (3), which provides a hydraulic force in an end region of a piston rod extension travel before reaching the maximum piston rod extension travel, which opposes the pull movement of the piston rod (3''').The damping piston (11''') has a circumferential groove (12''') in which a slotted sealing ring (16''') is received, which hydraulically seals in the groove (12''') in the said end region of the piston rod extension path when the piston rod (3''') moves in the tension direction and, when the piston rod (3'''') moves in the compression direction, lifts at least locally from a compression-side flank (14''') of the groove (12'''), which limits the groove (12''') on the side in the compression direction and points in the tension direction, in order to provide a defined permeability for a hydraulic damping medium between the groove (12''') and the sealing ring (16''').