Multilayer Rail Primary Spring With Frequency-Dependent Radial Stiffness
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Solution Overview
Problem
Existing primary springs in rail vehicles face challenges in maintaining optimal rigidity, particularly at high excitation frequencies, which leads to unwanted sleeger movement and increased wear on rails and wheels, while conventional solutions complicate construction and adjustability.
Innovation Solution
A primary spring design featuring fluid-filled chambers connected via a multilayer thrust spring with conical elastomer layers and a stiffening intermediate layer, allowing frequency-dependent rigidity adjustment without moving parts, reducing maintenance and wear, and optimizing force distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If high rigidity along the length direction is provided to prevent sleeger movement at high speeds, then the stability of the rail vehicle is improved, but the wheel axles cannot be tangentially in the cam arch during cornering, leading to increased wear on tracks and wheels
Solution Approach 1:
The patent applies the dynamics principle by making the rigidity of the primary spring frequency-dependent. At high excitation frequencies (straight track, high speed), the spring exhibits high rigidity to prevent sleeger movement. At low excitation frequencies (cornering, low speed), the rigidity automatically reduces, allowing wheel axles to be tangentially in the cam arch and reducing wear on tracks and wheels. This dynamic adaptation eliminates the need for manual adjustment or complex switching mechanisms.
2Device complexity
If conventional primary spring designs are used, then the construction is simple, but the rigidity cannot be adjusted frequency-dependently, leading to sleeger movement at high speeds
Solution Approach 1:
The patent employs hydraulic principles by filling the chambers within the elastomeric layers with fluid. The fluid can move between chambers depending on the excitation frequency, creating a frequency-dependent rigidity effect. This hydraulic approach allows the spring to automatically adapt its characteristics without moving parts, valves, or complex control systems, maintaining construction simplicity while achieving advanced rigidity control.
Solution Approach 2:
The patent changes the physical state and distribution of the fluid within the elastomeric layers based on excitation frequency. At different frequencies, the fluid redistributes between chambers, altering the effective rigidity parameter of the spring. This parameter change is automatic and continuous, providing adaptive rigidity control without requiring external intervention or complex mechanisms.
3Adaptability or versatility
If additional switching means or complex construction is used to adjust rigidity, then the adaptability is improved, but the device complexity and maintenance requirements increase
Solution Approach 1:
The primary spring is designed to be self-regulating, automatically adjusting its rigidity based on the excitation frequency without external control systems. The fluid within the elastomeric layers self-organizes and redistributes in response to dynamic conditions, providing adaptability while minimizing device complexity and eliminating the need for maintenance-prone switching means or 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
The solution provides a compact, low-maintenance primary spring with frequency-dependent radial rigidity adjustment, reducing sleeger movement at high speeds and minimizing wear on tracks and wheels, while allowing tangential wheel movement in curves, thus extending maintenance intervals and reducing noise.
Implementation Method 1
At least two fluid-filled chambers are provided which are connected to each other to exchange fluid between the chambers, depending on a forced excitation frequency, whereby the rigidity in the radial direction changes frequency-dependent
Implementation Method 2
allowing frequency-dependent rigidity adjustment without moving parts, reducing maintenance and wear
Data Source
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AI summary
The invention relates to a primary spring for a rail vehicle, comprising a central support element (4) having a longitudinal axis (5), a spring element and a receiving element (7), wherein at least two fluid-filled chambers (11, 12) are provided which are connected to one another in order to exchange fluid between the chambers (11, 12) in accordance with an imposed excitation frequency, whereby the stiffness is altered in a frequency dependent manner in the radial direction. In order to guarantee a particularly compact construction, according to the invention the spring element is configured as a multi-layered thrust spring (6) and comprises at least one inner elastomer layer (8) connected to the central support element (4), one outer elastomer layer (9) connected to the receiving element (7), and one stiffening intermediate layer (10) between the elastomer layers (8, 9, 18), wherein the elastomer layers (8, 9, 18) have a conical shape with respect to the longitudinal axis (5) and the chambers (11, 12) are arranged inside an elastomer layer (8, 9, 18).