Gearbox Output Shaft Research Articles

Modelling width of the spectral component of a gas-turbine engine gearbox output shaft speed

Gearbox is the most stressed component in an aircraft gas-turbine engine. This implies the need for finding ways to monitor its technical condition. Practice shows that the most efficient method is vibration-based diagnostics. However, this method requires the use of sophisticated measurement systems and highly skilled personnel. This paper shows that errors of gear coupling manufacture and assembly, characteristics of machine operating mode, design factors, frequency modulation of the carrier of the engine rotor speed in the stationary mode of its operation, and wear of teeth flanks determine the width of the spectral component of the gearbox output shaft speed. Using the results obtained from the developed model of the width of gear tooth spectral component, ratios for width of the spectral component of the signal of the “standard” tachometric speed sensor of the gearbox output shaft speed and the corresponding spectral component of its vibration were obtained. Models for repaired and newly manufactured gearboxes and gearboxes with tooth flank wear were proposed. This allowed the development of a number of new diagnostic indicators of a defect. Several examples of the use of these new diagnostic indicators are given for the gearbox of one of turbo-prop engines. The results obtained provide an opportunity to assess the gearbox technical condition in operation.

Evaluation of Tractor Quality Based on Vibration Characteristics

Problem. The overall development time for agricultural tractors is 7-10 years, with testing accounting for approximately 63-80% of the total time. Within testing, reliability testing under operating conditions comprises 58-73% of the workload. However, even after extensive testing, serially produced tractors often fail to meet the specified lifespan and reliability requirements. Final refinements are only made to tractors after a certain accumulation of operational faults, resulting in hidden defects remaining in the serial production of tractors, as testing primarily addresses major structural and manufacturing defects. Goal. The aim of this study is to evaluate the design and manufacturing quality of tractors based on their vibration characteristics. These characteristics can identify structural and technological defects that decrease the reliability and lifespan of tractors. Methodology. Analytical research methods were employed to improve the quality of traction electric motors for electric transportation. Experimental research methods and the determination of electric motor technical conditions based on their vibrodiagnostic parameters were utilized. Statistical methods were employed to process experimental studies. Results. Vibration measurement results indicated that tractors belonging to vibration class E are not recommended for serial production. These tractors have an estimated lifespan of 6-8 thousand engine hours and incur high maintenance costs compared to tractors of vibration class D. Tractors with vibration levels of class E are not recommended for serial production due to the excessive vibration load on components. Originality. The T-150K tractor family requires significant redesign of its structure, manufacturing processes for components, and bearing unit assembly. This is achieved through constructive measures, such as ensuring bearing preload in shaft supports, using class 4 precision bearings with a noise index of QE1, and providing a floating fit with a clearance of no more than 15 μm between the bearing and the housing. Introducing intermediate bushings into the design of gearbox output shaft bearings improves the accuracy of machining bearing seating surfaces and the assembly of bearing units. Practical value. The developed vibration evaluation methods for T-150K tractors enable the assessment of their design and manufacturing quality. The research data obtained during the design stage allows for more reliable predictions of tractor quality.

A Probabilistic Bayesian Parallel Deep Learning Framework for Wind Turbine Bearing Fault Diagnosis.

The technology of fault diagnosis helps improve the reliability of wind turbines. Difficulties in feature extraction and low confidence in diagnostic results are widespread in the process of deep learning-based fault diagnosis of wind turbine bearings. Therefore, a probabilistic Bayesian parallel deep learning (BayesianPDL) framework is proposed and then achieves fault classification. A parallel deep learning (PDL) framework is proposed to solve the problem of difficult feature extraction of bearing faults. Next, the weights and biases in the PDL framework are converted from deterministic values to probability distributions. In this way, an uncertainty-aware method is explored to achieve reliable machine fault diagnosis. Taking the fault signal of the gearbox output shaft bearing of a wind turbine generator in a wind farm as an example, the diagnostic accuracy of the proposed method can reach 99.14%, and the confidence in diagnostic results is higher than other comparison methods. Experimental results show that the BayesianPDL framework has unique advantages in the fault diagnosis of wind turbine bearings.

Development of a Virtual Bench for Modeling and Research of a Mobile Robot in Simintech

A virtual bench is designed for students studying simulation, model-oriented design of mechatronic systems and control devices. A review of existing virtual stands is performed. The training starts with simulation of a mobile robot (MR) with a single drive, for example, a transport robot moving along one coordinate, then simulation of MR with differential control moving on a plane, and then simulation of multicopters (quadcopter, hexacopter, octocopter). The virtual simulator consists of a model of MR with a single DC motor drive, MR controller, control panel. The drive model of the mobile robot in the state space is developed. Negative trends in the development of laboratory benches have been revealed: fast obsolescence of laboratory equipment; high cost; small range of equipment. Positive directions of their development have been identified: expansion of software capabilities (high-level languages) allowing to create any applications quickly and easily; appearance and improvement of special software used to create multimedia applications, as well as specialized software intended for design automation (AutoCAD, KOMPAS, Altium Designer, etc.) and mathematical calculations (Matlab, MathCAD, etc.). Software tools include SimInTech, MatLab/Simulink, LabVIEW, procedure-oriented languages VB, Delphi, Java, etc.; problem-oriented languages LISP, C++, C#, etc. In this connection, it is expedient to partially abandon traditional laboratory benches and switch to wider application of simulation modeling and computational experiment methods. Virtual laboratory benches should form the basis of such transition. As a result of simulation, the following parameters of MR model were obtained: MR displacement at 2.5 m, maximum gearbox angular speed 0.2 rad/s, maximum torque on gearbox output shaft 15 N∙m, maximum angular speed of DC motor 30 rad/s. Simulation of MR was performed in SimInTech program.

GEARBOX TEST RIG FOR SKYSPOTTER 150 HELICOPTER

SkySpotter 150 is an unmanned helicopter introduced recently by Modelárna LIAZ. The gearbox test rig developed for this helicopter has an innovative design. The drive is combined with a dynamometer and an axial force mechanism, which simulates the load from the main rotor on the gearbox output shaft. It leads to a special solution. The measurement methodology was developed including all sensors and design of the rig with a non-traditionally oriented dynamometer. The design has safety features that protect the test rig components and operator. The test rig is used for many tests during the development and improvement of the new helicopter generation. It also serves for verifying the gearbox parameters during its lifetime; it means tests of new gearboxes as well as technical diagnostic during periodical inspections.

Sago Extraction Machine Design

The production of sago starch in Papua is around 200 thousand tons per year, even though the potential is 4.75 tons of dry starch per year. The large potential for sago starch production cannot be realized optimally due to the low production capacity. The production capacity is doubtful because the sago processing process is still carried out traditionally. The problems encountered can be solved by applying machining technology to the sago production process. The application of technology in the form of production machines will improve the quality of sago starch and production capacity. The production capacity of sago starch can be increased through the application of technology in the production process. Especially the sago pith grating machine technology and sago starch extraction machine technology, because these two processes consume the most time when using traditional methods. The working principle of the sago starch extraction machine that has been made is that the rotation generated by the driving motor is channeled through the pulley transmission and the V-belt drives the gearbox, the rotation of the gearbox output shaft through the pulley transmission and the V-belt drives the stirring shaft. The production capacity of the sago extraction machine is planned to be 80 kg/hour. The design of the sago extraction machine uses wheels to facilitate the mobilization of the machine to the sago plantation area.

Investigation on planetary gearbox fault mechanism under variable speed conditions based on rigid-flexible coupling dynamics model

Dynamic behaviors of wind turbine planetary gears are greatly affected by the transfer paths and variable conditions. However, previous studies have mainly considered single transfer path and stationary operating conditions. To overcome this problem, a rigid-flexible coupling dynamics model of wind turbine planetary gearbox under different transfer paths and variable conditions is established. By simulating the modal-based rigid-flexible coupling dynamics model, the gearbox output shaft speed as well as the box vibration response in the stationary condition are obtained well, which can be characterized by its frequency features. By conducting order envelope analysis on the simulated acceleration signals in the variable speed condition, the feature order in the sun gear fault state is obtained on the simulated acceleration signal. The planetary gearbox dynamics tests results are in good agreement with the simulation results. The experiment results verify the correctness of the established rigid-flexible coupling dynamics model. This modeling method provides a new idea for multi-path modeling of wind turbine gearboxes and the study of fault mechanism under variable speed conditions.

The DESIGN OF A TRANSMISSION SYSTEM ON A BALL MILL MACHINE TO PROCESS HOMOGENIZATION OF BLACK POWDER USING AN AUTOMATIC SYSTEM

Abstract: In the military world, battle technology has experienced very rapid development, both close-range combat and long-range combat. In long-distance combat the technology that is often used is rocket technology where this rocket technology can paralyze the enemy in large numbers. Black powder is a mixture of potassium nitrate (KNO3), carbon powder (C) and sulfur (S). (Evie Lestariana, LAPAN). The black powder itself functions as an igniter filling material for the propellant combustion process. This research is to design a tool to support the manufacture of black powder in the igniter filling to help the combustion of rockets, especially those owned by the Indonesian Army. This study uses an experimental method using empirical calculations to get a tool with the desired specifications. Before carrying out the calculations, the author collects research data to carry out calculations, the data collected are as follows: 1. Roller shaft rotation: 246 rpm, 2. Roller shaft torque: 4.0697 Nm, 3. Roller shaft diameter: 25 mm, 4. Pulley shaft diameter top: 100mm. The results obtained after carrying out the calculations are the diameter of the driving pulley 98 mm, the belt contact angle against the pulley 174.6º, and the length of the V-belt 453.14 mm, moment of inertia on the gearbox output shaft 1884,8 mm4.

Increasing Wind Turbine Drivetrain Bearing Vibration Monitoring Detectability Using an Artificial Neural Network Implementation

The highest costs due to premature failures in wind turbine drivetrains are related to defects in the gearbox, with bearing failures being overrepresented. Vibration monitoring has been identified as the primary tool to detect and diagnose these types of failures. However, late or no signs of the failures are still being reported. Artificial neural networks (ANNs) has been shown to favourably be used as a classifier of bearing failures to increase the detection and diagnosis performance, which requires labelled data when training for all types of considered failures. However, less work has been done with an ANN used to create descriptive functions of the vibration and turbine operation data relationship and thereby negating inherent variance in the vibration data and increasing the detectability when a defect appears. Therefore, this study utilizes the relationship between the rotational speed recorded during a vibration measurement and the calculated condition indicator values of specific bearing failures in three wind turbine gearbox failures. An ANN establishes a function between the rotational speed and condition indicator values with healthy training data collected before the failure occurred. Thereafter, whole datasets leading up to the changing of the gearboxes is used to predict the condition indicator values without the failure influence. The difference between the predicted and true values show an increased sensitivity of the detection in two cases of gearbox output shaft bearing failures as well as indicating a planet bearing failure which with the previous data had gone undetected.

The results of the impact theory application in modeling the gear shifting processes in automatic transmissions

The process of gear shifting in vehicles automatic transmissions is considered in the paper as the shock interaction of transmission elements. Two mathematical models are proposed and considered for simulation the gear shifting processes. Computer simulation of the models’ movement during acceleration of a vehicle, as well as modes of low - and high-frequency gear shift cycling (self-oscillations of the output shaft of the gearbox) is carried out. Methods for decreasing the amplitude of the gearbox output shaft oscillations caused by the impact nature of gear shifting are proposed.

Vehicle’s transmission as a vibro-impact system

The article discusses a dynamic model of a dual-clutch transmission. The absence of a torque converter and the short duration of gear shifting (0.2 - 0.5 sec) in such transmissions allows to present the shifting process as impact interaction. As a result, the gear shift excites the oscillations of the gearbox output shaft. Thus, the transmission of the vehicle can be considered as a vibro-impact self-oscillating system.

The Use of an Improved LSSVM and Joint Normalization on Temperature Prediction of Gearbox Output Shaft in DFWT

In the working process of Double-Fed Wind Turbines (DFWT), it is very important to monitor and predict the temperature of the high-speed output shaft of the gearbox timely and effectively. Support vector machine has more advantages in the temperature prediction of wind turbines. Least squares support vector machine is suitable for online prediction due to reducing the computational complexity of support vector machine. In order to solve the sparsity of least squares support vector machine, an improved least squares support vector machine based on pruning algorithm is proposed in this paper to predict the temperature of the high-speed output shaft of gearbox using the practical data of Double-Fed Wind Turbines. At the same time, in order to improve the prediction accuracy and to solve the problem of few links between different feature parameters in common normalization method, the paper uses the method of joint normalization to preprocess the data. The principal component analysis is used to reduce the dimension of the data. Particle swarm optimization algorithm is used to optimize the parameters of the pruning least squares support vector machine. The proposed model that is established in this paper is a new model to forecast the temperature of the high-speed output shaft. The results show that its prediction accuracy is higher than that of other algorithms.

Bearing time-to-failure estimation using spectral analysis features

With the increasing use of health usage monitoring systems on helicopters, a lot of research has been undertaken for diagnosis of transmission components. However, most of these works are performed in laboratory environments and there are hardly any published works on in-service application. In this study, we present an experience in diagnosis of a helicopter gearbox bearing using actual service data gathered from AH64D helicopters belonging to the Republic of Singapore Air Force. A number of helicopters have been found with grease leak and radial play in the tail rotor gearbox output shaft during field maintenance. Subsequent tear-down inspections of the tail rotor gearboxes revealed that they had similar defects of bearing race spalling and widespread pitting of the rolling elements. Spectral analysis was carried out on the accelerometer data from these helicopters and correlated with the tear-down inspection findings. The fault patterns exhibited correspond well to progressing stages of bearing wear and are consistent across defective gearboxes from different helicopters. It is demonstrated that simple spectral analysis can be effective in tracking progressive stages of bearing damage using both low-frequency and high-frequency bandwidths. The observed fault patterns are extracted as features for diagnosis and used to determine the bearings’ estimated time to failure for maintenance planning.

Dynamics Performance and Abrasive Wear of the Automotive Drive Shaft

An automotive drive shaft is used in a front drive transmission vehicle for transmitting rotary movement from the gearbox output shaft to the wheels with a constant velocity. This paper presents the kinematic model of ball joint and tripod joint with consideration of clearance and proposes a simplified dynamics model of the drive shaft. The simulation of the dynamics model is given by the measured data. Also, the abrasive wear of the ball type joint is tested on the experimental setup with consideration of full loading. The results show that the dynamics of the motion will be affected by the clearance when the loading changes its direction. The motion will be stable due to the damping. It can be found that the abrasive wear of ball joint largely depends on the relative sliding velocity from the experiments. This will probably affectthe dynamics performance and the impact force, which will also cause the other type of failures.

Recursive methods in control of flexible joint manipulators

This paper considers recursive solving methods in the control of modular and reconfigurable robot systems. The focus lies on the end-point accuracy and recursive methods for its improvement. The modeling of the robot systems under consideration is done by the Projection Equation in Subsystem representation. Due to gear elasticities and the lack of position sensors at the gearbox output shaft, deflections of the end-point cannot be compensated by standard PD motor control. Therefore, a novel approach is presented in this contribution to correct the resulting position errors of the end-points of the robot systems. This proposed method enables to do a flat parameterization of such elastically modeled systems in a recursive manner, which is contrasted to the generally used non-recursive exact feed-forward linearization method in minimal form for such under-actuated systems. The ability to do the computation in such a recursive way offers the possibility to do the calculations systems for systems with many degrees-of-freedom (DOF) as well, where standard analytical methods reach their limits. And for modular systems, it is applicable as well. For validation, the proposed method is implemented for a robot arm with seven joints and simulation results are presented.

Dynamics Performance of the Front Drive Shaft with Clearances

An automotive drive shaft is used in a front drive transmission vehicle for transmitting rotary movement from the gearbox output shaft to the wheels with a constant velocity. The kinematics model of ball joint and tripod joint has been studied without consideration of clearance. This paper will propose a new model with consideration of the clearances on ball joint and tripod joint. The simulation results are given by using this model. The conclusions are made as well as the future work.

Study on the Abrasive Wear in a Ball Type Joint of Automotive Drive Shaft

Ball type joint is one of key component of automotive drive shaft, which is used in a front drive transmission vehicle for transmitting rotary movement from the gearbox output shaft to the wheels with a constant velocity. It has been found that the ball type joint is usually failure caused by abrasive wear. This paper is dedicated to analyze the abrasive wear by theoretical investigation on the relatively slipping velocity of each component of the ball joint, as well as the experimental approach. The results show that the grading of abrasive wear of the components is largely depended on the relatively slipping velocity.

Recursive Methods in Modeling and Control of Modular Robotic Systems

AbstractThis paper addresses the dynamical modeling and control of reconfigurable modular robots. The modular actuators (brushless DC motors with Harmonic Drive gears) for the robots under consideration are connected by rigid links. This way the robot can be assembled in different configurations by rearranging these components. For dynamical modeling the Projection Equation in Subsystem representation is used, taking advantage of its modular structure. Due to the lack of position sensors at the gearbox output shaft, deflections caused by the elasticities in the gears can not be compensated by the PD motor joint controller. Therefore, a correction of the motor trajectory is needed, which can be calculated as part of a flatness based feed‐forward control using the exact model of the robot. With the recursive approach proposed in this paper the concept of reconfigurability is retained. For validation a redundant articulated robot arm with seven joints is regarded and results are presented. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Failure of an Inclined Elevator

The failure and crash of an inclined passenger lift are examined and the probable cause together with a likely sequence of events is arrived at. This failure was in two parts; initially the gearbox output shaft suffered a fatigue failure, freeing the winch drum from the motor and normal brake. This was followed more importantly by the malfunctioning of the emergency brakes on the lift, allowing the lift to roll to the bottom of the run. The lift had been upgraded prior to its failure. Calculations show that the gearbox output shaft that failed was more than adequate for the loads imposed on it by the new controlled motor, whereas the original direct-on-line motor probably had overstressed the shaft. The steel lifting rope exhibited three severe kinks about 1 1/2 m from its attachment to the trolley. The search for the causes of these kinks led to the discovery that a lever mounted on the emergency brake shaft had been damaged and bent. Evidence came to light that the whipping action of the rope, following the release of the winch drum after the shaft failed, relocated the lifting rope under the lift cabin and over the safety equipment on the trolley. This abnormal location of the rope placed it in a position where it interfered with the movement of the lever and hence with the rotation of the emergency brake shaft. With this shaft restricted in its rotation the emergency brakes failed to apply properly.