Tribological Test Rig with Non-Circular Specimens and V-Band Braking
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Solution Overview
Problem
Existing model test rigs for tribological investigations on disk-shaped test specimens experience high dynamic loads due to complex drive systems, making it difficult to simulate sliding and rolling contacts similar to gear drives while minimizing additional dynamic loads and ensuring easy production, alignment, and adjustable test conditions.
Innovation Solution
The use of disk-shaped test specimens with non-round outer contours and a specific gear transmission system that allows for constant speed simulation, combined with a loading device that applies forces uniformly, reduces dynamic loads and allows for precise alignment and adjustment of test conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-stage coupling gearbox is used to translate constant speed into oscillating movements, then sliding and rolling contacts similar to gear drives are achieved, but very high accelerations and dynamic loads occur in the linkage mechanism
Solution Approach 1:
The patent extracts and eliminates the complex multi-stage coupling gearbox from the drive system. Instead, it uses a simple V-band brake mechanism that can be applied independently to each drum, removing the source of high dynamic loads while preserving the ability to simulate gear meshing conditions through controlled drum rotation and braking.
Solution Approach 2:
The patent replaces the mechanical multi-stage gearbox system with a friction-based braking system. The V-band brake uses friction between the band and drum surface to create the desired oscillating movements and contact conditions, substituting complex mechanical linkages with a simpler friction-based mechanism.
2Reliability
If a lifting device is used to load test specimens during forward movement and disengage during return movement, then tribological loading is achieved, but further dynamic loads are introduced into the model test rig
Solution Approach 1:
The patent merges the loading function with the braking mechanism. The same V-band brake that controls drum rotation also applies the tribological load to the test specimens during rotation, eliminating the need for a separate lifting device and reducing overall system complexity.
Solution Approach 2:
The V-band brake mechanism serves multiple functions: it controls the oscillating rotation of the drum, applies tribological load to the test specimens, and enables easy engagement and disengagement of loading. This multi-functional design eliminates the need for separate dedicated components.
3Reliability
If complex drive systems are used to achieve absolute sliding and rolling motions, then gear meshing conditions are simulated, but very high loads on linkage joints occur
Solution Approach 1:
The patent removes the complex linkage mechanism entirely, using direct drum rotation with V-band braking instead. This eliminates the intermediate linkage joints that would transmit high dynamic loads, while still achieving the desired sliding and rolling contact conditions on the test specimens.
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 configuration minimizes additional dynamic loads, enables realistic simulation of gear meshing conditions, and allows for efficient production and alignment of test specimens, resulting in a more accurate and cost-effective model test rig for tribological investigations.
Implementation Method 1
The actuator (47) acts on a V-band brake (50) in order to rotate the second drum (32) against the direction of rotation
Implementation Method 2
The loading device (45) comprises a servo-hydraulic or an electromagnetic actuator (47)
Data Source
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AI summary
A model test stand (1) for the tribological examination of disk-shaped test specimens (11, 12, 13, 14) is characterised in that all four disk-shaped test specimens (11) to (14) have non-circular outer contours (20) with a continuously variable curvature including a first portion (21) and a second portion (22) that lie on opposite sides of an axis of symmetry (18) and that mirror each other at this axis of symmetry (18), and in that all the disk-shaped test specimens (11 to 14) have a centre (15) through which the axis of symmetry (18) extends with a smallest distance (23) to a point of intersection between the axis of symmetry (18) and the non-circular outer contour (20) at a first point (25) of the contour and a greatest distance (24) to the other point of intersection between the axis of symmetry (18) and the non-circular outer contour (20) at the second point (26) of the contour.