Rail Impact Absorber Cone Angle Design for Force Control
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Solution Overview
Problem
The force path characteristic of existing impact absorbers is not linear, leading to excessive force at the start of deformation, which results in irreversible damage and increased mass due to large diameter and wall thickness requirements.
Innovation Solution
The forming surface and cone area of the impact absorber are designed with different angles relative to the movement axis, allowing for line contact and reduced initial forming force, and a lubricant space is created to reduce friction, with a guide section to ensure defined deformation and prevent contact corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the deformation tube has a large diameter and/or large wall thickness to provide required energy dissipation, then the energy absorption capability is improved, but the mass of the impact absorber increases
Solution Approach 1:
The invention changes the geometric parameters of the deformation tube by introducing a conical area with a specific cone angle (α) that is smaller than the semi-vertical angle (β) of the conical depression. This parameter change optimizes the deformation characteristics to achieve required energy dissipation with reduced mass compared to conventional cylindrical deformation tubes
2Area of stationary object
If the forming surface and cone area have the same angle to achieve full-surface contact, then the contact area is maximized, but the initial forming force becomes excessively high
Solution Approach 1:
The invention applies preliminary action by designing the conical area with a smaller angle than the conical depression, creating a controlled line contact condition during initial deformation. This preliminary geometric configuration ensures that full-surface contact is gradually achieved only after the deformation tube has moved a certain distance, thereby reducing the peak initial forming force while still maximizing the contact area for energy absorption
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 results in a smoother force characteristic, reducing the initial forming force and maintaining a constant force level after full-surface contact, minimizing weight and preventing force peaks, thus enhancing energy absorption efficiency.
Implementation Method 1
the forming surface and the cone area delimit a lubricant space. During a deformation movement, the lubricant enclosed in the lubricant space is displaced into the contact area between the die and the deformation tube and forms a friction-reducing lubricating film.
Data Source
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AI summary
The invention relates to an impact absorber (1), in particular for a rail vehicle, comprising at least one deformation pipe (3), which is connected to an impact plate (5), and which in an impact event, is moved along a matrix (9) having a conical forming surface (11). The deformation pipe (3) has a cone region (25), which is in overlap with the forming surface (11) of the matrix (9). The forming surface (11) of the matrix (9) and the cone region (25) enclose a differing angle (α, β) with respect to an axis of movement (17) of the deformation pipe (3).