Rail Wheel Brake Disc Mounting for Thermal Expansion Relief
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Solution Overview
Problem
The existing wheel brake disc mounting methods for rail vehicles lead to uneven thermal expansion and high dynamic stresses on linking elements due to rigid mounting, causing failure from dynamic fatigue and thermal deformation, especially in high-speed trains.
Innovation Solution
The wheel brake disc is designed with two ring-shaped halves attached to the wheel using linking elements that include an eyebolt, nut, sliding key, and disc springs, allowing relative movement during braking and heat input, reducing prestress force and dynamic tension, while the shape of cooling ribs and edges enhances stiffness and air recirculation for improved cooling and reduced air resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid mounting is used to attach brake disc to wheel, then structural stability is improved, but dynamic stresses on linking elements increase causing failure from dynamic fatigue
Solution Approach 1:
The patent applies the dynamics principle by replacing rigid fixed mounting with a dynamic mounting system that allows controlled relative movement between the brake disc and wheel. The linking elements incorporate sliding keys and disc springs that enable the brake disc halves to move freely during thermal deformation, converting the static rigid connection into a dynamic adaptive connection that accommodates thermal expansion and contraction without generating excessive dynamic stresses.
2Device complexity
If rigid mounting is used to attach brake disc to wheel, then mounting simplicity is improved, but thermal deformation stresses increase causing bolt failure
Solution Approach 1:
The patent implements dynamics by designing a mounting system where the brake disc halves can dynamically adjust their position relative to the wheel during thermal cycles. The sliding keys within guided pockets and the disc springs create a mechanism that automatically accommodates thermal deformation, allowing the structure to adapt to temperature changes without generating damaging stresses in the linking elements.
Solution Approach 2:
The patent applies parameter changes by modifying the mechanical properties of the mounting system to allow controlled movement. The disc springs provide variable stiffness that changes with compression, and the sliding keys enable positional changes within the guided pockets. These parameter changes allow the mounting system to transition from a rigid fixed-state to a flexible adaptive-state during thermal deformation.
3Ease of manufacture
If cooling ribs are made straight and simple, then manufacturing ease is improved, but air recirculation and cooling efficiency decrease
Solution Approach 1:
The patent applies the curvature principle by replacing straight cooling ribs with contoured, curved cooling ribs that follow an optimized path between the braking surfaces. These curved ribs create more effective air flow channels that promote recirculation of cooling air through the brake disc thickness, enhancing heat dissipation efficiency while maintaining manufacturing feasibility through standard forming processes.
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 significantly reduces dynamic stresses on linking elements, prolongs the life of brake discs and linings, and achieves energy savings through reduced air resistance, with a brake disc lifetime of 2 million km and cost savings of €1300-2500 per disc-electric or €2400-4700 per disc-diesel per million km traveled.
Implementation Method 1
The linking element 2 comprises an eyebolt 3, a nut 4, a sliding key 5 and a disc spring 6
Implementation Method 2
the shape of cooling ribs ensures increased brake disc stiffness and low air resistance, and together with the outer and inner edges of the brake disc, air recirculation is improved in the area where the linking bolts are attached
Implementation Method 3
The large temperature gradient resulting from braking causes uneven thermal expansion of the brake disc. The braking surface, where the heat input takes place, is much hotter than the inside of the brake disc or the point where the brake disc is attached to the wheel
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A wheel brake disc (1) for rail vehicles with improved mounting, the wheel brake disc (1) comprising two ring-shaped halves (1a, 1b), each attached to the wheel on its side by means of linking elements (2) which are equally spaced apart from each other, wherein the linking element (2) passes through a through hole (8) formed in the wheel, wherein the linking element (2) comprises an eyebolt (3), a nut (4), a sliding key (5) and disc springs (6), wherein a fastening of the linking element (2) on one side of each half (1a, 1b) of the brake disk (1) is achieved through the sliding key (5) that is fastened to a designated pocket (7) formed at corresponding positions on each half (1a, 1b) of the brake disc (1), and the fastening of the linking element (2) on the corresponding second side of each of the two halves (1a, 1b) of the brake disc (1) is achieved through the nut (4) and disc springs (6) inserted in a bore (8b) for the insertion of the nut (4) and the disc springs (6), thereby reducing the number of bores (8b) on the braking surface for the insertion of the nut (4) and the disc springs (6) by half