Nested Multi-Stage Shock Absorber to Prevent Bottoming Out
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Solution Overview
Problem
Conventional shock absorbers with hydraulic dampening devices face issues with 'bottoming out' during strong shocks, leading to uncomfortable rides and potential mechanical failures, and existing solutions that add multiple pistons increase the overall length of the device, which is not feasible for all vehicles.
Innovation Solution
A multi-stage, nested piston and shaft design where a second shaft is telescopically disposed within a first shaft, allowing both to move independently through a cylinder filled with hydraulic fluid, with a reservoir to regulate pressure and additional features like apertures and valving washers to manage fluid dynamics and prevent excessive movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple pistons are coupled to the shaft at fixed positions, then the dampening capability during strong shocks is improved, but the overall length of the shock absorber increases
Solution Approach 1:
The patent implements a nested piston configuration where a second piston is disposed within the first piston, and a third piston is disposed within the second piston. This nesting arrangement allows multiple pistons to occupy the same spatial envelope, providing enhanced dampening capability across multiple stages without increasing the overall length of the shock absorber. Each piston operates at different displacement stages, creating a progressive dampening effect.
Solution Approach 2:
The shock absorber is segmented into multiple independent piston stages, each responsible for dampening specific ranges of displacement. The first piston handles initial displacement, the second piston engages at intermediate displacement, and the third piston engages at maximum displacement. This segmentation allows the system to provide appropriate dampening force at each stage without requiring all pistons to be fully extended, thus maintaining compact length.
2Device complexity
If a single piston moves through hydraulic fluid, then the device structure is simple, but the device bottoms out during strong shocks causing mechanical failure
Solution Approach 1:
The nested piston design allows three pistons to be arranged concentrically within the same cylindrical space. The outer first piston, middle second piston, and inner third piston each provide dampening at different displacement levels. This nesting provides the reliability of multi-stage dampening without the complexity of three separate cylindrical chambers, maintaining a relatively simple overall structure.
Solution Approach 2:
The system dynamically engages different piston stages based on the magnitude of displacement. During normal operation, only the first piston is active. During strong shocks, the second and third pistons progressively engage as displacement increases. This dynamic engagement prevents bottoming out by providing progressive resistive force that adapts to the shock magnitude, while maintaining structural simplicity.
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 effectively absorbs large forces without increasing the length of the dampening device, providing a smoother ride and preventing mechanical failures by managing pressure and fluid flow efficiently, thus enhancing the durability and performance of shock absorbers.
Implementation Method 1
Movement of the shaft in turn moves the piston through the hydraulic fluid, thereby causing friction between it and the hydraulic fluid within the defined volume of the cylinder. As the shaft moves through the fluid, the coefficient of friction becomes greater, resulting in an increasing 'stiff' cushion which slows the movement of the piston and thereby dampens the force of the vehicle's movement.
Implementation Method 2
a hydraulic device containing a fluid which converts mechanical movement of the incoming displacement of the shock absorber into heat which is then dissipated into the surrounding environment
Implementation Method 3
an external spring coupled between an external portion of the shaft and the cylinder is compressed, further dampening the incoming force or shock of the vehicle's suspension system. After the initial shock, the upward force placed on the shaft and piston is relaxed, thereby allowing the compressed external spring to expand and push the piston and shaft back into the opposing direction until an equilibrium is once again obtained.
Data Source
AI summary
A shock absorber having a plurality of pistons in a telescopic or nested configuration. The shock absorber has a first shaft with a first piston disposed within a cylinder filled with a hydraulic fluid. A second shaft is in turn disposed within the first shaft, the second shaft having a second piston extending beyond the position of the first piston. The second shaft is further coupled to a vehicle's suspension system. When undergoing a displacement, the second piston moves through the cylinder and compresses an external spring. After the second shaft has been fully extended, the first piston is then actuated, thereby also moving through the hydraulic fluid. As the pistons traverse through the cylinder, a volume of the fluid is pushed into a reservoir communicated to the cylinder. Both the first and second shafts are configured to move independently with respect to each other and to the cylinder.