Shock Absorber Sub-Valve Durability via Stress Distribution
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Solution Overview
Problem
Existing shock absorbers face durability issues due to excessive deflection and stress concentration in disk valves, which can lead to damage.
Innovation Solution
The shock absorber incorporates a sub-valve with a sub-disk smaller in diameter than the main disks, clamped by the main disks and seat portion, featuring a restricting portion and communicating holes to limit opening and reduce stress concentration, enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sub-valve is designed to open fully to maximize damping force control, then the damping force characteristics can be optimized, but the sub-disk experiences excessive deflection and stress concentration leading to reduced durability
Solution Approach 1:
The patent introduces communicating holes in the sub-disk to change its structural parameters. These holes reduce the flexural rigidity of the sub-disk, allowing it to deflect more easily during opening while reducing stress concentration. This parameter modification enables the sub-disk to withstand repeated opening cycles without excessive stress accumulation, thereby improving durability while maintaining functional performance
2Force
If the sub-disk is made larger to increase damping force, then the damping characteristics improve, but the degree of opening becomes excessive causing damage to the sub-valve
Solution Approach 1:
The patent applies local quality by creating communicating holes at specific locations in the sub-disk. These holes are strategically positioned to reduce flexural rigidity where needed while maintaining the overall size and damping force capability of the sub-disk. This localized structural modification allows the sub-disk to control its opening degree without sacrificing the damping force generated by its overall dimensions
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 design improves the durability of the sub-valve by reducing stress concentration and flexural rigidity, preventing excessive deformation and increasing the degree of freedom for setting damping force characteristics.
Implementation Method 1
deflected and lifted to open the sub-passage upon receiving the pressure of hydraulic fluid in the sub-passage
Implementation Method 2
The valve body is provided with a restricting portion that abuts against the sub-disk when the sub-valve is opened to limit the degree of opening of the sub-valve
Implementation Method 3
the sub-disk is provided with a communicating hole radially inward of a position at which the sub-disk abuts against the restricting portion
Data Source
AI summary
A shock absorber including a piston (3) slidably fitted in a cylinder having hydraulic oil sealed therein. A flow of hydraulic oil, induced in a passage (10) and a sub-passage (29) by sliding movement of the piston in the cylinder in response to the stroke of a piston rod, is controlled by an extension main valve (14) and a compression sub-valve (15) incorporated in the extension main valve, thereby generating a damping force. The amount of deflection of a sub-disk (30) constituting the compression sub-valve when the sub-disk is opened is limited by restricting portions (21). The sub-disk is provided with communicating holes (31) to reduce a differential pressure acting on the sub-disk when opened and also to relax the concentration of stress in the sub-disk, thereby improving the durability of the sub-disk.