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The constant growth of the automotive market demands for comfort to the user and energy efficiency have caused the intensification of the industry researches and development of the automatic transmissions (AT). However, vehicles equipped with these gearboxes entails in higher fuel consumption levels than the one required by vehicles equipped with manual transmission. In the automotive industry due to the advantages offered using computer simulations, such as fast evaluation an optimization, many researchers are using virtual models for optimization of dynamic behavior of systems and fuel consumption. Aiming to study the dynamic behavior of an AT and the influence of its components on that behavior, this paper presents an AT dynamic model developed in MATLAB® / Simulink®.

Clutches are mechanisms used for coupling between shafts in order to transmit torque from one to the other. This coupling is made mechanically by friction between the parts with a high friction intermediate material. In this process, the slippage between the parts becomes a source of heat that makes the system temperature to raise up to high values. Under high temperature, the capacity of torque transmission of the clutch can be reduced by the variation of the effective contact diameter, once the contact region of friction change as the temperature is rising. This is caused by the thermal-displacement effect induced by the friction. The torque capacity also can be affected by the friction coefficient that varies with the temperature. Therefore, in order to design an optimized system, it is necessary an analysis of the parts and materials under the influence of temperature changing.

This paper presents a standardization model for the analysis of rolling bearings in transmission systems. A procedure was applied to assist gearbox prototype development. A solid methodology with robust software, based on international standards, allowed the development engineers to shorten simulation time. In this case, the calculations were performed taking into account system elasticity, which resulted in an exact calculation of the internal load distribution in the bearing, including contact pressure, tilted position and with rolling element profile, considering effects of lubrication conditions and contamination. The program also evaluates the resulting forces of gears, displacement, shaft deflection, contact pressure, stresses, torsion and inclination of the shafts. All the information processed aims at providing safe design, optimal solution and cost impact.

Clutch systems applications require that their components resist to high dynamics and static efforts that should be considered in the development process. These requirements are determined taking account the vehicle application, such as loadcases, materials, life time and environment conditions. In the case of CRB components generally the design is based on contact angular ball bearing. Normally static analysis are performed, computing stresses and displacements, however in this specification the results are checked using static and fatigue safety factors according to the strength assessment evaluation, Germany standard: FKM (Richtlinie - Rechnerischer Festigkeitsnachweis für Maschinenbauteile). Actually more powerful computers have reduced gradativally the cost for industries and with the constant improvements of FE programs, it is possible to simulate the complete assembly using contact interactions to get closer to the reality.

The main objective of this work is the structuration of a complete software for reliability analysis of mechanical components, as well its application in failure tests to obtain useful lifetime employed in some advanced maintenance techniques. The software has a theoretical revision for better understanding of the basics concepts of reliability and it presents procedure to evaluate reliability functions through the main statistical methods. Making use of the statistical theory applied to components and systems trials, the most common types of trials and their application to the sample population were studied. Basics concepts as parametric and non-parametric trials and descriptive statistic are applied. Afterwards, it was made an analysis of correlation and regression of the obtained data from the trials and curve fitting (lineal, logarithmic, exponential, etc.).

The design of Clutch Release Bearings (CRB) is usually based on angular contact ball bearings. This kind of bearings supports both axial and radial loads and the load limits depend directly on the contact angle. The CRB has its own particularity, since it is a radial angular contact ball bearing and its main load is on axial direction. Due to this special situation, this work is done to evaluate this CRB design according to the classical theory of bearing life calculation, developed by Lundberg and Palmgren (1947), which the standard ISO 281 is based on. The analysis is focused on the basic dynamic load rating of the bearing, which briefly means the expected load that the bearings support a life of 1 million cycles. This expectation follows a Weibull distribution with increasing failure ratio and a specific reliability.

Nowadays, the development of new technologies in the automobilist industry has increasing the incorporation of electronics into mechanic systems, what reflects on safer and more reliable mechanisms. This study will present the development of a sensor detent pin for the switchgear unit, which combines an electronic sensor to a detent pin, reducing the number of mechanic components as consequence. Its main function are the comprehension of shifting and selection movement and gear positions (neutral and reverse), as well as send these informations by means of electric signals to a central computer.

Every year, the market expects greater quality and reliability not only from the newly released products, but also from common daily use goods. In this case, even a simple part, as a rolling element bearing, can be the root cause for a “product failure”. Unusual noise and vibrations are common issues for costumers, who in that case normally avoid using the vehicles. In rolling element bearings, most of the failures that produce noise and vibrations, are related to the contact stress and fatigue of raceways and rolling elements. Thus, it is essential to understand the contact mechanisms and, therefore, the lubrication conditions of these systems. In this work, the Elastohydrodynamic (EHD) lubricated point contacts are studied. The most important goal is to understand the influence of the elliptic ratio on the oil film and the contact pressure.

To overcome the proposals concerning to the reduction of the fuel consumption and gases emissions required by the regulatory councils around the world, but also required by the actual market, since economic vehicles have been more valorized than ever, the automotive industry have dispended considerable efforts in the development of new technologies, such as hybrid cars, and in the improvement of the current projects. Friction of any magnitude retards the motion and results in energy loss, causes temperature increase and should be reduced in order to improve the system efficiency. This paper intends, by means of analytical calculation based on dynamic systems and comparisons with Finite Elements Analysis, propose a robust method to analyze friction losses in automotive mechanical systems. Transmission application was chosen to conduct this analysis.

In order to increase the efficiency of internal combustion engines, Schaeffler Technologies recognized that it is necessary to identify the sources of energy losses, quantify such losses and to study ways to minimize them. Based on this premise, the Front End Accessory Drive parameters had to be investigated to locate where further potential enhancement is hidden. This paper aims to analyze and discuss about the main sources of energy losses occurring in FEAD and propose ways to optimize the system to the optimal range of efficiency and durability. Investigations showed that there are some loss points of the basic belt drive components which have good potential to be reducible, e.g., losses at bearings and belt.

One of the great challenges of engineering teams nowadays is to overcome long and costly project experimentation phases. One effective way of decreasing such project demands is to come up with a firsthand prototype with high success probability. In order to do so, the project team should rely on robust numerical models, which can represent most of the real-life product behaviors, for instance system dynamics. For rolling element bearings, such dynamic models have to consider the dynamic interactions between its components, i.e., rolling elements and raceways. The only vibration transmitting points on rolling element bearings are the lubricated contacts. Therefore, in order to represent the full bearing dynamic behavior on a numerical model, an efficient transient contact model, which depicts the actual contact behavior, is fundamental.

Sustainability is the focus of most engineering projects nowadays. The challenge of taking the efficiency to its maximum, in order to reduce the CO₂ emission, became so hard that even a minor innovation is a relevant step. Among the efficiency villains in automotive branch it is possible to quote the mechanical friction losses. One of the main factors concerning to these sort of losses is the contact pressure in rolling bearings. This pressure is highly influenced by singularities on raceways. Different geometry profiles can be a friction source, affecting the usage and leading to a wasteful exploitation. This paper aims to scrutinize the influence that different abnormalities on raceways has on the contact pressure of high speed and low load axial ball bearings. The study will be based on numerical simulations on a contact calculation software. The contact pressure will be evaluated around the edges of dented, bulged, grooved and ridged profiles.

The synchronization system was created with the intention to make easy the gear engaging in automotive transmissions. The speed difference of the shafts is reduced during the gearshift operation by means of sliding friction of the synchronizer rings. The constant friction performance can be improved and the wear can be simultaneously reduced either by additives in the oil of the transmission or by careful selection of the friction material for the synchronizer rings. Nowadays, brass or steel meet the requirement of both friction surface and resistance on the driving lugs. The friction coefficient of the surface can be increased by scatter sintered coatings, molybdenum or carbon linings that are joined to the carrier material using complex manufacturing processes. A new concept transforms this continuous friction lining into many single friction elements that are guided by "pockets" in the synchronizer ring.

Due to the current changes in the automotive industry several new technologies are being developed and the old ones analyzed. The epicyclic gear trains, or planetary gear trains, are important in the automatic transmissions. In this paper a model is presented to describe the behavior of the transmission during the process of gear change. For this the system chose must be fully described, that means the relation among the rotations of the components must established.

Epicyclic gear trains are important part of automotive transmissions. They are present in automatic transmissions and in differentials of most vehicles. The dynamic behavior of a single epicyclic gear is well known, and this study presents the results obtained based in a model of a complete transmission. Initially the Wilson gearbox is presented. The main principles of the model are described. Following, the results of a simulation using the model are shown. Finally, the influence of the inertias in the model are presented and it is done some discussion about it

More efficient and more reliable methods to analyze the performance of the bearing test samples help to reduce validation time during development of rolling bearings. This paper presents a study of the impact on airborne noise and structural borne noise of especial prepared rolling bearings with angular contact submitted for durability tests. The study aims to link specific bearing failures to characteristics in airborne noise and structural borne noise using for instance the “envelope technique”. In the future these patterns will enable more effective online monitoring of failure evolution.

One of the vital parts in the modern motor vehicle is the transmission. Any fault on the system can hazard the usage of the vehicle, especially if the fault occurs during the operation, in that case safety will be an issue. Thus, in order to improve reliability and durability of transmissions systems and its components, virtual simulations can help the designer to overcome faulty conditions during the design conception. However, many times the simulations do not relate to the real world application, due to simplification and assumptions that were formally known as appropriate. For that reason, during the process of designing a transmission bearing, it would be important to take into account the housing stiffness effects on the bearings. In this work, three different cases will be evaluated. In first case, bearings life will be simulated on an analytical software with a rigid housing.

There are large numbers of variables that affect seal performance, for example, temperature, grease and dusty. This paper aims the study one of these variables, the swelling. Swelling is the absorption of the liquid by the rubber and this liquid absorption can deeply alter physical and chemical properties and hence change tensile strength, extensibility and hardness of the rubber. A review about seal and the characteristics of the seal performance will be made and also a study about what this phenomenon affects the seal performance. Thus the purpose of the present paper is to develop the conception of swelling by investigating the characteristics of swelling deformation.

Heating generation in rolling bearings is a critical point for development and application, specially for heavy trucks. Several problems can occur in the rolling bearing and in the system when the temperature increases. For example, at high temperature levels the rubber sealing can change its proprieties and volume, creating a high interference at the contact with the rings. The grease can also be affected and modify its viscosity, generating a possible leakage, which is not allowed during life. This papers aims to study the heat generation and evaluate, experimentally, the temperature stabilization in clutch release bearings for heavy duty application. With this purpose, several tests were performed and the results were analyzed to find the main factors that can be influenced.