Experimental and Theoretical Investigation of Vibro-Impact Motions of a Gear Pair Subjected to Torque Fluctuations to Define a Rattle Noise Severity Index

Vibro-impacts are common in various automotive engine and transmission gear applications. They are known to cause excessive noise levels, often called rattling or hammering. Input and output fluctuations acting on such systems cause tooth separations and sequences of impacts allowed by backlash at the gear mesh interfaces. The fluctuations leading gear rattling have often been studied for specific applications with the excitations produced typically by an internal combustion engine. As such, rattle evaluations have been often empirical and specific to the systems considered. In this study, an experimental test set-up of a gear pair is developed to emulate the same torque fluctuations in a laboratory environment. This set-up is used to establish an impact velocity-based rattle severity index defined by the measured torsional behavior of the drive train that is shown to correlate well with the measured sound pressure levels. With that, a validated dynamic model of the experimental setup is employed to predict the same index to allow estimation of rattle noise outcome solely from a torsional dynamic model of the drivetrain. Predicted rattle severity indexes are shown to agree well with the measured ones within wide ranges of torque fluctuations and backlash magnitudes, allowing an assessment of rattle performance of a drivetrain solely from a torsional model.

SIMULATION OF A DUAL CLUTCH AUTOMATED TRANSMISSION GEAR SHIFT

A computer dynamic model of an automobile transmission with a double dry clutch, created using the "Universal Mechanism" software package, is presented. Work objective is to analyze the possibility of improving double dry clutch efficiency at various controls of compressive forces of clutch plates. The computer model contains 7 bodies: an engine crankshaft, two clutch plates, two gearbox input shafts for odd and even gears, an output shaft, a fly wheel. The simulation of gear shifting shows that pressing a clutch pedal or letting out the clutch simultaneously, cutoff time increment increases the rotational speed justification of the engine shaft and the input shaft of the actual gear, the total work of the friction forces of both clutches and does not affect the maximum value of clutch plates rotary sliding resistance. Frictional energy of the clutch when shifting gears from lower to higher is greater than when shifting gears from higher to lower. Sequential clutch on-off reduces the total frictional energy of both clutches by 1.17...1.31 times compared to simultaneous one. The model allows looking into different gearshift modes with uniform velocity or accelerated vehicle motion, optimize the gearshift strategy.

Prediction of Mechanical and Toughness Properties of Ni-Modified Cr-Mo Alloy Steels for Transmission Gear

The purpose of the study was to predict the mechanical and toughness properties of Ni-modified alloy steels by adding 1.55%, 1.75%, and 1.95% of Ni-content to the existing Cr-Mo alloy steel of transmission gear material. Typically transmission gears have been working under severe working situations of loads and rotations. Due to these situations, the properties and qualities of gear materials are highly affected consequently, fatigue failure is instigated. So, improving the mechanical and toughness properties of the existing gear material is very vital and compulsory since these properties have a direct impact on gear fatigue failure. Investigations have been done on determining the mechanical and toughness properties of the Ni-modified Cr-Mo alloy steels, through ANN modeling prediction by associating the complex relation of input (chemical composition, tempering temperature) and output parameters (mechanical and toughness properties), and verified by experimental test approaches. Explored these materials property with ANN modeling and experimental test show that the more Ni-content added to the Cr-Mo alloy steel, the higher the ultimate and yield strength can achieve at every instant of tempering temperature. Likewise, fracture toughness, impact toughness, and percent of retained austenite of these materials were also investigated thoroughly as tempering temperature varies. Thus, a 1.55 % Ni-modified Cr-Mo alloy steel has a higher value of both impact toughness and fracture toughness compared with other Ni-modified alloy steels. Similarly, surface hardness was slightly decreased as the amount of Ni-content added increased at each instant of tempering temperature. Lastly, based on both predicted and experimental results, 1.55 % of Ni-modified Cr-Mo alloy steel showed a better combination of mechanical and toughness properties. Keywords: ANN modeling; Yield strength; Ni-modified; Tempering temperature; Fracture toughness; Surface hardness

CONCEPTUAL DESIGN OF CONTROL ROD DRIVE MOTOR TYPE MAGNETIC JACK FOR NUCLEAR POWER PLANT

The Control Rod Drive Motor (CRDM) controls the reactor power of a G.A Siwabessy and automatically shuts it down during an emergency using a three-phase motor that drives a ball-nut spindle attached to the magnetic SCRAM through the transmission gear. However, there are several weaknesses associated with this design, such as the inability of the ball nut to rotate when a disturbance occurs at the motor limit switch continuously. This causes the threads on the control rod shaft to wear out due to friction and release from the holder. Therefore, this research aims to develop a CRDM with a magnetic jack for a nuclear plant, which moves the extension shaft and the control rod components vertically and linearly. The control rod's motor must pull, insert, hold, or drop it from any point. This conceptual design is the first step in determining prototyping design criteria with a magnetic jack to understand the working mechanism. The control rod gripping motion simulation was also presented using ANSYS Rigid Dynamics to reduce the failure at the design phase before prototyping. The simulation results showed no collision on each component capable of affecting the overall system performance. Therefore, the control rod motor functions properly in carrying out the pulling and lowering movements on 19.1 mm infrequency.

IOT ENABLED PNEUMATIC GEAR SHIFTING IN TWO-WHEELER

The present automatic transmission is fully mechanically controlled and costs very high. In this study, a gear shifting mechanism was designed and applied on a featured bike to make the gear transmission process faster and less destructible for the driver using internet. But the gear transmission mechanism designed makes driving easier and to achieve efficient driving. This new device must be reliable, has small dimensions, economical and low maintenance cost. This project aims to improve the gear shifting process with a suitable control mechanism to implement in clutch featured bikes. According to the suggested gear shifting method, which selects the transmission gear as per the speed of the vehicle without direct human interference. A pneumatic shifter is a mechanical device that uses compressed air to shift a gear controls the engaging and disengaging of gears using internet of things principle to control automatically. There is no lag time in a gear shifting operation and taking hold in the rest of the vehicles.

A Representation Generation Approach of Transmission Gear Based on Conditional Generative Adversarial Network

Gear reliability assessment of vehicle transmission has been a challenging issue of determining vehicle safety in the transmission industry due to a significant amount of classification errors with high-coupling gear parameters and insufficient high-density data. In terms of the preprocessing of gear reliability assessment, this paper presents a representation generation approach based on generative adversarial networks (GAN) to advance the performance of reliability evaluation as a classification problem. First, with no need for complex modeling and massive calculations, a conditional generative adversarial net (CGAN) based model is established to generate gear representations through discovering inherent mapping between features with gear parameters and gear reliability. Instead of producing intact samples like other GAN techniques, the CGAN based model is designed to learn features of gear data. In this model, to raise the diversity of produced features, a mini-batch strategy of randomly sampling from the combination of raw and generated representations is used in the discriminator, instead of using all of the data features. Second, in order to overcome the unlabeled ability of CGAN, a Wasserstein labeling (WL) scheme is proposed to tag the created representations from our model for classification. Lastly, original and produced representations are fused to train classifiers. Experiments on real-world gear data from the industry indicate that the proposed approach outperforms other techniques on operational metrics.

Axial Flux PM In-Wheel Motor for Electric Vehicles: 3D Multiphysics Analysis

The Axial Flux Permanent Magnet (AFPM) motor represents a valid alternative to the traditional radial flux motor due to its compact structure; it is suitable for in-wheel applications so that the transmission gear can be suppressed. The modeling of the motor is a purely Three-Dimensional (3D) problem and the use of 3D finite element tools allows the attainment of accurate results taking also into account the effects of the end-windings. Moreover, a 3D multiphysics analysis is essential to evaluate not only the motor performance and its thermal behavior, but also the electromagnetic forces acting on the surfaces of the stator teeth and of the magnets that face the air gap. Moreover, as the vehicle’s motors often work in variable-speed conditions, the prediction of vibrations and noise for electric motors over a wide speed range is usually necessary. The paper presents a double-sided AFPM motor for a small pure electric vehicle; the basic drive architecture includes four axial flux motors installed directly inside the vehicle’s wheels. The aim is to propose advanced and integrated electromagnetic, vibroacoustic and thermal analyses that allow the investigation of the axial flux motor behavior in a detailed and exhaustive way.