End-of-stroke cushioning via progressive orifice restriction
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Solution Overview
Problem
Existing sliding device damping mechanisms, such as those in vehicle suspension systems, are expensive and complex due to the intricate shapes required for effective damping, and they often fail to provide proportional damping based on both position and speed, leading to suboptimal comfort and noise reduction.
Innovation Solution
A sliding device with a cylindrical ring sliding on the rod and calibrated orifices in the rod wall, where the ring progressively covers the orifices to reduce fluid passage section, allowing for simpler and more economical construction while providing adjustable damping characteristics by modifying the orifice configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex damping means with intricate sliding rings and sleeves are used, then effective end-of-stroke damping is achieved, but manufacturing cost and device complexity increase significantly
Solution Approach 1:
The damping function is segmented into multiple calibrated orifices distributed axially along the rod, each contributing to progressive damping as the ring covers them sequentially. This replaces the single complex variable-thickness ring design with multiple simpler fixed orifices, reducing manufacturing complexity while maintaining damping effectiveness
Solution Approach 2:
Instead of manufacturing a complex variable-thickness sliding ring, the patent uses a simple cylindrical ring that copies the basic geometric form, relying on the calibrated orifices in the rod to provide the progressive restriction effect. This simplifies the ring manufacturing to standard cylindrical forms while achieving the same functional result through the orifice configuration
2Reliability
If robust damping components with precise geometry are used to withstand pressurized fluid stresses, then damping reliability improves, but manufacturing precision requirements and cost increase
Solution Approach 1:
The rod wall is given local quality through calibrated orifices with specific dimensions and distributions at different axial positions. Each orifice is precisely calibrated to provide the desired flow restriction, while the overall structure remains simple. The sliding ring maintains a simple cylindrical geometry with standard tolerances, avoiding the need for complex variable-thickness machining
Solution Approach 2:
The damping characteristics are controlled by changing parameters of the calibrated orifices (diameter, position, distribution) rather than changing the geometry of the sliding ring itself. This allows precise control of damping under pressure through orifice calibration while keeping the ring structure simple and easy to manufacture
3Ease of manufacture
If simple damping structures are used, then manufacturing cost and complexity are reduced, but the ability to provide proportional damping based on position and speed is compromised
Solution Approach 1:
The calibrated orifices are pre-configured in the rod at specific axial positions and dimensions during manufacturing. The sliding ring is designed with a predetermined diameter that ensures it covers the orifices in the correct sequence during extension. This preliminary configuration enables automatic progressive damping based on position without requiring active control, maintaining manufacturing simplicity while providing adaptable damping characteristics
Solution Approach 2:
The system provides dynamic damping adaptation through the interaction between the sliding ring and calibrated orifices. As the ring moves axially during extension, it dynamically covers different numbers and sizes of orifices, automatically adjusting the effective flow area based on position and velocity. This creates progressive damping characteristics without complex active control mechanisms
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 solution enables the production of a sliding device with improved damping characteristics that reduce noise and shocks at the end of travel, enhancing comfort by providing proportional damping based on both position and speed, while being more cost-effective and simpler to manufacture.
Implementation Method 1
calibrated orifices in the wall of the rod and distributed axially, the orifices and the ring being configured so that the fluid displaced by the sliding movement of the device is pushed back through the orifices, the passage section of said orifices being progressively reduced when they are covered by said ring
Data Source
AI summary
The invention relates to a sliding device (2) such as a suspension element, comprising a cylinder (8, 18), a piston (30) mounted in the cylinder in a sliding manner, a rod (6) connected to the piston (30), the rod (6) being axially hollow and comprising a wall, means for damping one of the two sliding movements of the device, said means comprising a cylindrical ring (22) that slides on the rod (6) and is movably connected to the cylinder (8, 18), and longitudinally distributed openings (26, 28) calibrated in the wall of the rod (6). The openings (26, 28) and the ring (22) are designed such that the fluid displaced by the sliding movement of the device is discharged via openings, the passage cross-section of which is progressively reduced as the ring covers the openings.