Face Run-out Research Articles

Analysis of the problems of using disc brakes in the complex of long drums of mine hoists with increased rope capacity

Purpose. After analysing the current literature in the field of mine hoisting, to determine the prospects for the use of disc brakes in a complex of mine hoisting machines with increased rope capacity with a long cylindrical cutter drum. To identify the problems associated with the end runout of the sheath and an increase in the deviation angle that arise when operating drums with a long casing in order to optimise their use. The methods. The study identifies the problems of using disc brakes in combination with long drums of increased rope capacity, as well as the associated increase in the value of the deviation angle and the length of the rope string. A computer experiment was carried out to find the dependence of the end runout of the sheath on its length under the action of a steady external pressure modelling the operation of a coiled rope, using the example of the sheath of the drum TsR-6.75×6.2/1.95. Findings. The article considers the problem of stiffness of long drums of hoisting machines, the increase in length of which occurs due to the increase in the depth of extraction, as well as the use of disc brakes in such hoisting machines. A computer experiment has been conducted to determine the dependence of face runout on the length of the hoisting machine drum shell. Thus, with the lengthening of the shell, the end runout increases, which can interfere with the safe operation of the disc brake. The originality. For the first time, a calculation methodology for determining the axial stiffness of long drums of mine hoists with increased rope capacity was developed and substantiated using the example of the drum of the TsR-6.75×6.2/1.95 machine with the help of the SolidWorks and MathCAD software complex. Generalisation of data on the relationship between drum length and deviation angle, which are critical for the safety and efficiency of mine hoists. Practical implementation. The implementation of the methodology will solve the problems with the use of disc brakes in the complex of mine hoists with long cylindrical drums of increased rope capacity, namely, with the end runout of brake discs, as well as an increase in the value of the deviation angle, increasing the efficiency and safety of mine hoists. This will eliminate the need to install additional support supports when lengthening the rope string to prevent longitudinal and, as a result, transverse vibrations. Ensure more stable and safe operation of mine hoists by optimising the design and braking systems.

Frequency-scanning interferometry for axial clearance of rotating machinery based on speed synchronization and extended Kalman filter

Rotor-stator axial clearance is a crucial design parameter affecting rotating machines' efficiency and safety. To realize accurate dynamic axial clearance measurement in high-speed rotating machinery with frequency-scanning interferometry (FSI), this paper proposes a novel algorithm of Doppler error suppression. By introducing rotor speed simultaneously as a Kalman filter parameter, the extended Kalman filter model is constructed by combining the a-priori information of rotating machinery. The feasibility is tested and verified by both simulation and experiment. This algorithm can suppress the Doppler error in FSI measurement and separate the axial movement and end face runout in real-time. Under laboratory conditions, a position measurement precision of ±3.5μm was achieved for rotation speed changing around 2400rpm.

Progressive control devices with auto-generator transducers of mechanical displacements

Two types of control devices with non-contact auto-generator transducers of mechanical displacements are considered: heads for size tolerance control, oriented to CNC machines and coordinate measuring machines, and devices for measuring stations of control and sorting machines. New devices are presented for controlling the face runout of parts such as bodies of revolution and controlling the mass of parts. Keywords: auto-generator displacement, transducer, discrete signal, accuracy, screen, control head. Yakov_Liberman@List.ru, Lubov202055@yandex.ru

Research on cold mechanical vibration of air-cooled disc brake

Cold mechanical vibration of air-cooled brake disc is mainly caused by the non-uniform geometry, including disk thickness variation (DTV) and side face run-out (SFR). A mathematical model consisting of the non-uniform geometry is constructed, which is imported into the dynamic brake model established by Lagrange equation as initial parameters. The braking moment fluctuation during braking process is obtained by MATLAB software. The experimental verification is realized based on Link3900 NVH test platform, where result shows that the calculated brake pressure is quite consistent with the test value. By single variable method, the key influence factor that affected braking moment fluctuation is analyzed, including DTV, SFR, friction coefficient, contact stiffness coefficient and damping coefficient. The conclusion shows that reducing these parameters within a certain range can significantly reduce the amplitude of cold vibration, except for the contact damping coefficient.

Validation of a thermo- and a hydromechanical model of a brake system for high-speed rail applications

This research deals with a numerical and experimental investigation of the vibratory frequency and the thermal response of a railway brake disc and pad under varying conditions. Railway brake systems play a vital role in passenger safety and comfort. The performance of disc brakes with regard to the dynamic effects like brake torque oscillations and brake judder depends on the contact properties and wear surfaces. Brake fading occurs due to accumulated frictional heat thereby reducing the stopping power. For an improved understanding of the complex processes of a brake system during long-term braking, a comprehensive numerical investigation is performed initially using the finite element software Abaqus for a thermomechanical and modal analysis. While the thermomechanical analysis based on the calculations of frictional heat is used to investigate the increase of temperature during braking, the contact pressure is a crucial parameter that influences the distribution of temperature both on the brake disc and on the pads. The modal analysis is used to investigate the frequency behaviour of the vibrations. Then, a simulation model of a self-energised electrohydraulic brake provides the results of brake force oscillations with regard to the observed topologies of the brake disc’s wear surface, which is measured at a full-scale test rig by an enlarged experimental set-up. In addition to the dynamic brake force, the set-up contains the online measurement of the side face run-out and the temperature of one side of a ventilated brake disc. By comparing the results of our experimental and numerical investigations, the simulation models are validated. Future research should focus on a thermomechanical analysis that considers heating, cooling, and the wear effects. A detailed implementation of the contact pressure distribution between the brake pads and disc can lead to a more precise prediction of brake torque oscillations. The achieved results can be used to improve riding comfort and resolve safety critical problems in high-speed trains.

Investigation of parts assembly error, taking into account the deviation of the shape of their surfaces

In this article, we study the errors in the assembly of parts, taking into account the deviation of the shape of their surfaces. The developed computer model of the assembly of the engine low-pressure turbine rotor is designed to predict the values of the assembly parameters, such as radial and face run-out. The forecasting of the above assembly parameters is carried out based on the data of actual dimensions and shape of the surfaces of parts assembled as an assembly unit. The analysis of study results made it possible to obtain a conclusion about the qualitative influence of geometrical errors of the assembled parts on the error of the assembly parameters.

Quality Inspection System of Circular Saw Blades Based on Eddy Current Inspection and Laser Measurement

Aiming at the problem of the complicated process, the low precision and efficiency of crack detection and key geometric feature of the circular saw blade, the quality detection system of the circular saw blade based on the nondestructive testing and laser measurement technology is studied. By using the laser measurement technology and optimizing the data processing method, the face runout, the thickness of the circular saw blade are measured. The crack defects in the tooth root region of the circular saw blade are detected by eddy current nondestructive testing technology. The system achieves the radial detection of 1mm radial sawing, the detection accuracy of the round beating is> 0.03mm, and the thickness measurement accuracy is> 0.005mm.

An instrument for measuring the mean surface profile of seal faces

The design, construction and performance of an instrument for measuring the surface profile of nominally flat seal-rings associated with an experimental mechanical seal are described. The device, which utilizes the principles of the aerostatic thrust bearing, is capable of measuring profiles of a few microinches amplitude superimposed on a face run-out greater by two orders of magnitude.