Shock Absorber Damping Adjustment via Segmented Flow Paths
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Solution Overview
Problem
Existing pressurized shock absorbers with positive pressure build-up face challenges in adjusting damping characteristics for small and large pressure differentials, and in generating rapid force build-up, especially with small pressure differentials, leading to complex and costly valve designs and potential cavitation issues.
Innovation Solution
The solution involves a shock absorber with separate ducts and adjusting elements that allow for independent adjustment of damping characteristics based on pressure differentials, using a leakage flow duct for small pressures and high-speed ducts for large pressures, with check valves controlled by spring forces to manage flow and prevent cavitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single valve design is used to handle both small and large pressure differentials, then the device complexity is reduced, but the ability to separately adjust damping characteristics for different pressure conditions deteriorates
Solution Approach 1:
The patent divides the valve system into two separate ducts: a first duct for handling small pressure differentials and a second duct for handling large pressure differentials. Each duct has its own adjusting elements, allowing independent adjustment of damping characteristics for different operating conditions without increasing overall system complexity
Solution Approach 2:
The patent introduces a check valve as an intermediary element that automatically directs flow between the first and second ducts based on pressure differential conditions. This mediator enables the system to switch between different damping adjustment modes without requiring complex control mechanisms
2Ease of manufacture
If conventional shock absorber design is used, then manufacturing cost is reduced, but cavitation occurs and force build-up is slow
Solution Approach 1:
The patent implements a positive pressure build-up system that pre-pressurizes the damping medium in the common volume before high-pressure conditions occur. This preliminary pressurization prevents cavitation from occurring in the first place, eliminating the need for expensive anti-cavitation materials or designs while maintaining reliability
3Reliability
If damping medium flow is restricted to prevent cavitation, then reliability is improved, but the capacity to allow sufficiently large damping medium flow deteriorates
Solution Approach 1:
The patent segments the flow paths into two separate ducts with different flow capacities. The first duct is optimized for small pressure differentials with lower flow capacity to prevent cavitation, while the second duct is optimized for large pressure differentials with higher flow capacity to maintain productivity during high-demand conditions
Solution Approach 2:
The system dynamically switches between the first and second ducts based on operating conditions. The check valve automatically directs flow through the appropriate duct, allowing the system to adapt its flow capacity to match the actual pressure differential and maintain both reliability and productivity across varying 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
This approach allows for separate and efficient adjustment of damping characteristics for small and large pressure differentials, ensuring rapid force build-up even with small pressure differentials, while minimizing cavitation and maintaining optimal damping performance at high speeds.
Implementation Method 1
a spring arranged in the common volume and pressing the check valve onto the seat
Implementation Method 2
a check valve, which opens as soon as the pressure in the common volume exceeds the pressure in the chamber having the lowest pressure at that particular instant
Implementation Method 3
A pressurized shock absorber with positive pressure build-up always has a pressure greater than zero on both sides of the piston arranged in the damping cylinder
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a method in a shock absorber (1) of separating the adjustment of the damping characteristics for small or large pressure differentials over the main piston (7). Arranged in the shock absorber is a damping medium-filled damping cylinder, divided into two damping chambers (8, 9) by a main piston (7) fixed to a piston rod (8). At least one duct (38a, 38b) is arranged in the main piston (7) or in the piston rod (8) in order to allow a certain damping medium flow between the damping chambers (8, 9). Also connected to the shock absorber (1) is a pressurized member (23), arranged in a pressurization reservoir (22). The pressurized member (23) pressurizes a volume (22a), common to both of the damping chambers (8, 9), to a certain basic pressure, which varies between 5 and 30 bar. This common volume (22a) is connected by separate flow ducts (27, 27') to the respective damping chambers (8, 9). Two separate adjusting elements (17, 17') are arranged between the common volume (22a) and the respective damping chambers (8, 9). These comprise one or more damping force- generating one-way valve (s) (18, 20) of a type known in the art and a check valve (19, 21). The check valve (19, 21) is subjected to and kept in a closed position by a force (Fs). With small pressure differentials over the main piston (7), the damping medium is prevented from flowing between the damping chambers (8, 9) via the adjusting elements (17, 17') but is forced to flow through the duct (38b) in or on the main piston.