Damper Assembly Piston Rod Sealing for Adjustable Damping
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Solution Overview
Problem
Existing hydraulic damper units are complex, expensive, and prone to errors due to their intricate structure, which makes them difficult to manufacture and maintain, and they often require large flow cross sections that weaken the cylinder structure and increase costs.
Innovation Solution
A damper unit with a simplified design featuring an axially slidable element on the piston rod, a sealing element to control fluid flow, and a polygonal inner wall shape in the cylinder, which allows for adjustable damping characteristics based on insertion speed and reduces structural weaknesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a complex hydraulic damper design with multiple components is used to achieve velocity-dependent damping, then the damping characteristic can be adjusted, but the device complexity increases and manufacturing costs rise
Solution Approach 1:
The patent combines the sealing element and the velocity-dependent damping control function into a single integrated component. The sealing element with axial openings serves both as a seal and as the flow control mechanism, eliminating the need for separate damping control components and reducing overall device complexity while maintaining adaptability.
Solution Approach 2:
The sealing element is designed to perform multiple functions simultaneously: it seals the gap between the piston rod and cylinder wall, provides velocity-dependent damping control through its axial openings, and acts as a structural support. This multi-functionality reduces the total number of components needed in the system.
2Adaptability or versatility
If large flow cross sections are provided in the cylinder to enable fluid flow, then the damping force can be adjusted, but the cylinder structure is weakened and manufacturing costs increase
Solution Approach 1:
Instead of providing large flow cross sections throughout the entire cylinder, the patent concentrates the flow control function in the axial openings of the sealing element located at the piston rod end. This localized approach allows damping force adjustment without compromising the overall structural integrity of the cylinder body.
Solution Approach 2:
The sealing element with its axial openings acts as an intermediary component that mediates between the need for fluid flow and the need for structural strength. It provides the necessary flow paths for damping control while being a separate element that does not compromise the cylinder's structural framework.
3Manufacturing precision
If multiple sealing elements and complex piston structures are used to control fluid flow, then precise damping control is achieved, but the ease of manufacture decreases
Solution Approach 1:
The patent merges the sealing function and the flow control function into a single sealing element component. This integration reduces the number of parts that need to be manufactured and assembled, simplifying the manufacturing process while maintaining precise damping control through the carefully designed axial openings in the sealing element.
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 solution provides a cost-effective, robust damper unit with adjustable damping forces that depend on insertion speed, ensuring precise control and reduced risk of damage to adjacent components during flap closure in motor vehicles.
Implementation Method 1
a cylinder filled with a damping fluid, preferably a hydraulic fluid, in which a piston rod is guided in and out
Implementation Method 2
the damping fluid can flow in a predetermined manner between the two compartments
Implementation Method 3
an elastic element, in particular a compression spring, acts in the insertion direction of the piston rod between the piston base element and the stop
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Damper unit comprising a cylinder (14) filled with a damping fluid, in which a piston rod (12) is guided in and out along an axial direction of the cylinder (14), wherein the piston rod (12) is associated with a bottom surface extending substantially in a radial direction between the piston rod (12) and an inner wall (14c) of the cylinder (14) and having at least one axial opening (28a) which defines an effective flow cross-section for the damping fluid; wherein the piston rod (12) comprises at its leading end in the insertion direction into the cylinder (14): a sleeve element (22) fixed axially to the piston rod (12); a piston bottom element (28) axially slidably supported on the piston rod (12), which comprises the bottom surface; an elastic element (26);and a closing element (34) fixed axially to the piston rod (12), which forms an indirect or direct stop for the piston base element (28) in the insertion direction of the piston rod (12), wherein above a predetermined insertion speed of the piston rod (12) into the cylinder (14) the bottom surface of the piston base element (28) comes into contact with an end face (22b) of the sleeve element (22) against the action of the elastic element (26) due to the dynamic pressure of the damping fluid, wherein the effective flow cross-section for the damping fluid is reduced by the interaction of the end face (22b) of the sleeve element (22) and at least one axial opening (28a) of the bottom surface of the piston base element (28).