Browse Topic: Constant-velocity joint

Items (109)
Research on Fractal Friction Model between Balls and Arc Raceways inside a Ball Joint2020-01-10934/14/2020
During the operation of the ball joint, its service life and transmission efficiency are affected by the internal friction. Taking the ball joint as the research object, based on fractal theory, the friction between the steel ball and the raceway inside the ball joint of an automotive drive shaft system is studied in this paper. During the analysis, the friction between the steel ball and the arc raceway is regarded as the friction between a sphere and an arc raceway surface. In order to describe the friction state more accurately, this paper proposes a correction coefficient to modify the distribution function of contact asperities in the plane, and obtains the distribution function of contact asperities between the sphere and the arc raceway surface. The correction coefficient is related to the load, the size parameters and the material parameters of the steel ball and the raceway. Then based on the modified distribution function, the fractal models of the friction coefficient, the tangential force (the friction force) and the normal contact load between the steel ball and the raceway are established. Finally, the correction coefficient is verified by the finite element model, while the relationship between the correction coefficient and the load, the relationship between the friction force and the normal contact load, and the relationship between friction coefficient and fractal parameters are analyzed through numerical examples.
Feng, HuayuanLi, XiHua
New Half Shaft Bench Test Methodology for NVH Characterization2019-01-15586/5/2019
The main purpose of this paper is to develop a reliable bench test to understand the vibratory behavior of the half shafts under applied torque comparable to an idle condition. In some cases, the half shaft path is a major factor influencing the idle vibration in the vehicle. At idle condition vehicle vibrations are caused by engine excitation and then they pass through different paths to the body structure. Half shaft manufacturers generally characterize shaft joints for their frictional behavior and typically there is no data for vibration characteristics of the half shaft under idle conditions. However, for predictive risk management, the vibratory behavior of the half shaft needs to be identified. This can be achieved from measured frequency response functions under preloaded test conditions. This bench test enables manufacturers to conduct comprehensive design of experiments on the impact of powertrain vibration input while transmitting through the half shaft into the vehicle system. This method enables the study of the half shaft at the component level, because studying the half shaft at vehicle level is difficult since other paths are present. This paper describes the bench test methodology and presents certain boundary condition challenges of the half shaft measurements, the design of the test rig and the preliminary joint behavior results on the test bench.
Siavoshani, SaeedVesikar, Prasad BalkrishnaYuan, WeiAbbas, AhmadSturla, Francisco Antonio
Integrated Multi-Physics Simulation for Full-Vehicle Low Frequency NVH Optimization in HEVs2019-01-14556/5/2019
The recent automotive industry trend towards electrification has created new challenges for NVH engineers. These challenges stem from new powertrain architectures and their complex interactions, the governing control strategies which aim to optimize energy management, and new unmasked sources of excitation. Additionally, vehicle manufacturers are attempting to reduce hardware testing in order to rapidly satisfy increasing production demand and to minimize its costs. Hence, to meet the above-mentioned challenges up front in the development process of Hybrid Electrical Vehicles (HEVs) while balancing competing design objectives of drivability, durability and NVH, a simulation-led design and optimization is required. NVH problems are often the result of mechanisms that originate through complex interactions between different physical domains (flow, electromagnetic, structural/mechanical, control logic, etc.) and the assembly of individual components into a complete system. Therefore, accurate system-level integrated models are becoming a requirement to solve modern NVH problems. Combining the optimal balance between simulation and experimental data, this article describes a joint effort between Ford and Gamma Technologies to develop a general methodology to perform full-vehicle low frequency NVH analysis. Using GT-SUITE software, a non-linear multi-physics simulation model of a rear wheel drive HEV was created. The model was exercised to accurately evaluate the effects of powertrain control strategy and component selection on low-frequency NVH performance during a tip-in regeneration, downshifting and in-gear acceleration maneuvers while minimizing the computational cost.
Gomez, Llorenc ForasteZeman, JonathanLiu, Jack
Driveline Boom Noise Reduction through Simplified FEM Approach2017-26-02151/10/2017
In today's competitive automobile marketplace with reduced vehicle development time and fewer prototypes/tests, CAE is playing very crucial role in vehicle development. Automobile environment demands ever improving levels of vehicle refinement. Performance and refinement are the key factors which can influence the market acceptance of vehicle. Driveline is one of the key systems whose refinement plays critical role in improved customer satisfaction. Because of the virtue of the driveline functionality, driveline induced noise and vibration are the most common issues in the AWD vehicle development programs. Refinement of the drive line needs complicated nonlinear full vehicle CAE MBD models for the evaluation of driveline induced noise and vibration responses at different operating conditions [1]. In this paper a simplified approach is adapted for solving the Noise & Vibration issue which has been identified at the prototype testing level of an AWD vehicle development. Linear finite element method is used as a basic tool in identifying the root cause and propose the design solution. In presented work full flexible FE driveline model was built for modal analysis and the ODS was matched with test behavior. After establishing the correlation between the FE and Test, different system variables were optimized to reduce the system level response. Later these solutions were evaluated for seat vibrations and cabin noise levels. This technique can be used where the time, resources and system inner details are not available or those are limited to build the complete nonlinear CAE models. With this simplified approach it was possible to quickly resolve the driveline induced N&V problem.
Krishna, Kodali AjayPatil, Sanjeev
Retrofitting of an Electronic System to Control and Data Acquisition in an Automotive Dynamometer for Didactic Use2015-36-02819/22/2015
Integrated controls for commercial dynamometers do not have appropriate characteristics to perform research and teaching tasks. These are developed to perform quick tests and its logic is prepared to obtaining the information in accordance with the technical standards. This way, the use for research is hindered because it does not have an interface that allows a refinement to the desired data ranges, t data sampling and the type of load that is applied. Its use for teaching is limited because these "standard" controls does not allow to analyze or to determine engines characteristics that are not covered through tests specified by the standards, so the use of this tool as an important part in professional training formed by the institution. The development of a system control to the electromagnetic brake and capture of torque and rotation data will allow better use of dynamometers for research and teaching, providing to the students the knowledge of the control system itself and data acquisition where parameters such as temperature and pressure can be added, improving the accuracy of torque and power measurements. This system will be made available to other educational and research institutions interested in the use of a control and data acquisition system designed for teaching and research in the engine area, with a low cost of development and operation.
Vandresen, MarceloSilveira, JamesPereira, MiltonChaplin, RichardFernandes, Gustavo
Brake Noise Prediction Using Altair Multi-Body Simulation2015-36-00025/13/2015
The level of noise transmitted to the passengers of a vehicle can drastically impact a passenger's comfort. Brake noise will give the customer an impression of poor product quality and can thus damage the quality image of the company. Within the automotive industry, the study of mode coupling instability by the use of FEM and modal complex analysis is widespread to reduce this phenomenon. In this paper an alternative method is presented, where potential brake noise issues are predicted by the use of a time transient integration using multi-body system analysis. The simulation model contains a nonlinear contact description, bushing, flexible bodies and the axis kinematics of the vehicle. Transient results are transformed by Fourier for a frequency domain study. The parameters that can be varied for the prediction analysis are brake pressure, vehicle speed, friction laws, system damping and bushing properties. The advantages of the multi-body system analysis approach are in the direct consideration of the non-linearity's which are significant within certain frequency ranges. The multi-body system analysis approach also provides a further method to confirm results from the complex modal analysis and thus increases the informational value of the numerical predictions. Simulations variant results will be presented and discussed and enhancements will be proposed.
Sundaresh, KeshavLeila, Felipe Moretti
Car-in-the-Loop Complete Vehicle Test Rig2015-01-06474/14/2015
During the last years mechatronic systems developed into one of the biggest drivers of innovation in the automotive industry. The start of production of systems like dual clutch transmission, lane departure warning systems and active suspensions proves this statement. These systems have an influence on the longitudinal, steering and vertical dynamics of the vehicle. That is why the interaction on vehicle level is crucial for an optimal result in the fields of efficiency, comfort, safety and dynamics. To optimize the interaction of mechatronic systems, in this paper a new test rig concept for a complete vehicle is presented. The so-called Car-in-the-Loop-concept is capable of realistically reproducing the loads, which act on the powertrain, the steering and the suspension during a test drive. The resulting advantages are the possibility to exactly reproduce test procedures, the independence from weather conditions and a minimization of the risk of human injuries during testing of safety functions. A prototype of this concept, which includes parts of the powertrain, the steering and the chassis corresponding to the left front side of a BMW Mini Countryman, was built at the lab of the Institute for Mechatronic Systems in Mechanical Engineering of the TU Darmstadt. A test rig shaft connects the wheelhub of the BMW Mini Countryman to actuators, which generate realistic loads corresponding to the current driving situation. To provide the needed adaptiveness for the steering and suspension movement constant velocity joints and ball-spline supported length compensations are included in the test rig shaft. A highly dynamic test drive is being reproduced on the prototype to prove the functionality of the Car-in-the-Loop-concept.
Fietzek, RafaelRinderknecht, Stephan
Control Strategy for the Longitudinal Degree of Freedom of a Complete Vehicle Test Rig2012-01-02324/16/2012
The Institute for Mechatronic Systems in Mechanical Engineering (IMS) designed a concept for a test rig, which enables the simulation of longitudinal, steering and vertical dynamics for a complete vehicle under laboratory conditions. The main part of the test rig concept is a shaft, which contains three constant velocity joints and two ball-spline supported length compensations. It connects the wheel hub of the test car to an electric motor. In addition a linear actuator is mounted to the middle part of the shaft and a hydraulic actuator replaces the suspension strut. These actuators can load the longitudinal, steering and vertical degree of freedom of the test car according to simulated driving maneuvers. A prototype of this concept is being built at the IMS lab. Beginning with a precise explanation of the test rig concept this paper discusses the control strategy for the rotational speed of the wheel hub of the car mounted on the test rig based on a simulation. The following issues have to be considered. The shaft connecting the electric motor to the wheel hub has an elasticity, which cannot be neglected. As the actuator and sensor position are not collocated and this is an unrestrained degree of freedom, a model based control approach like for instance pole placement is required to assure stability. In this context the effect of the placement of the poles on the longitudinal dynamics will be evaluated. Another factor, which has influence on the longitudinal dynamics, is the torque in the vehicle power train, which is regarded as a disturbance. In a vehicle it can only be observed over the bus system with insufficient accuracy. For this reason a disturbance feedforward strategy is explained and the influences of the accuracy of the power train torque are reviewed.
Rinderknecht, StephanFietzek, RafaelMeier, Torben
Power Train Model Refinement Linked with Parameter Updating Through Nonlinear Optimization2010-01-14216/9/2010
In the virtual development process validated simulation models are requested to accurately predict power train vibration and comfort phenomena. Conclusions from refined parameter studies enable to avoid costly tests on rigs and on the road. Thereby, an appropriate modeling approach for specific phenomena has to be chosen to ensure high quality results. But then, parameters for characterizing the dynamic properties of components are often insufficient and have to be roughly estimated in this development stage. This results in a imprecise prediction of power train resonances and in a less conclusive understanding of the considered phenomena. Conclusions for improvements remain uncertain. This paper deals with the two different aspects of model refinement and parameter updating. First an existing power train model (predecessor power train) is analyzed whether the underlying modeling approach can reproduce the physical behavior of the power train dynamics adequately. Thereby especially rotational irregularities of the power train causing the low frequency boom noise are considered. Based on the example “tire model”, different model improvements are investigated by means of sensitivity analysis. Efficient measures are chosen to validate the quality of the results in comparison to test results. A manual approach by a stepwise analysis of each parameter is time consuming and often does not lead to accurate results due to nonlinear model behavior. Furthermore, the interdependence of an increasing number of parameters can hardly be managed manually. Therefore, the second part of the paper focuses on parameter identification methods through nonlinear optimization based on full vehicle measurements. The whole optimization process - from the formulation of the objective function to the analysis of the results - is discussed. The model improvements as well as the parameter optimization are based on vehicle tests of an all-wheel driven passenger car. The combination of model refinement and updating with non linear optimization methods demonstrates an effective approach to fine-tune simulation models for an optimum support in the product development process.
Girstmair, JosefPriebsch, Hans H.Reich, FranzZehetner, Josef
Development of a Multi-Body Systems Approach for Analysis of Launch Shudder in Rear Wheel Driven Vehicles2009-01-20735/19/2009
Driveline shudder is a low-frequency (10 Hz - 30 Hz) vibration issue of vehicles that can occur under various test conditions. Specifically, launch shudder is an issue that can be prevalent under vehicle take-off conditions. Factors that typically contribute to launch shudder include stick-slip excitation of friction materials (clutches) and driveline excitations, in particular, on rear wheel drive (RWD) vehicles. Shudder caused by the driveline excitation is generally related to the universal joints (Cardan joints) in the driveline system. In this case, the u-joint forces and kinematics induce a 2nd order excitation when operated under a driveline angle. This document focuses on launch shudder phenomena resulting from driveline system excitation on a RWD vehicle. An initial treatment of the physics governing launch shudder and typical factors influencing the shudder levels in vehicle are provided. Following this, the development of a multi-body systems (MBS) based approach is described. The results from the model are shown to correlate well with experimental measurements on a test vehicle. Upon demonstrating good correlation, the MBS model is utilized to conduct sensitivity analyses with respect to key design factors that influence launch shudder. Finally, the results are summarized and suitable conclusions provided.
Wellmann, ThomasGovindswamy, Kiran
The following definitions and illustrations are intended to establish common nomenclature and terminology for universal joints and driveshafts used in various driveline applications. In addition, useful guidelines are included for the application of universal joints and driveshafts. For more specific details, see Universal Joint and Driveshaft Design Manual, AE-7.
Drivetrain Standards Committee
This SAE Recommended Practice outlines the qualification testing and performance related criteria of elastomeric boot seals used in constant velocity joint applications. These applications are referred to as front- wheel-drive halfshafts or axles, but can also be utilized in rear-wheel-drive halfshaft applications. For additional information regarding CV joint systems and their applications refer to SAE AE-7 “Universal Joint and Driveshaft Design Manual.”
Drivetrain Standards Committee
Analytical Studies on Sealing Design for CVJ Boot2004-01-13243/8/2004
This paper presents a new concept of thermoplastic polyester elastomer boot (here in after referred to as TPEE boot) fitted for inboard, constant velocity universal joint (here in after referred to as CVJ). The CVJ has an irregularly shaped, tri-lobed housing for the purpose of weight and noise reduction. In this investigation, we carried out a series of analysis using FEM to develop the boot design. Our successful TPEE boot comprises two distinct features: (1) a boot with its inner surface sealing portion shaped to fit the outer surface of tri-lobe CVJ housing, and (2) a grommet to be fitted onto the boot and fastened by a clamp from the outside. Conventional boots for CVJ with tri-lobe shaped housing usually have a sealing portion of cylindrical profile, and a bushing is applied therein to fill the clearance between the CVJ housing and the boot sealing portion. The novel concept described herein is a particular method of applying a grommet outside of the boot. Therefore, when a clamp is applied and fastened thereon, satisfactory contact pressure is established between the CVJ housing and the TPEE boot. In addition, the clamping force is directly applied on the CVJ housing, which enhances the sealing performance of the boot. Because of the TPEE material for the boot, the low temperature effects have been taken into consideration. By means of FEA, we predicted the formation of clearance caused by a difference in thermal shrinkage between the CVJ housing and the boot. We also carried out FEA to determine if there is grease leakage through the boot sealing portion arising from the boot slip at the start of rotation at low temperature operating condition. Based on the FEA results, we developed a more robust TPEE boot that could provide satisfactory sealing under any operating conditions.
Iwasaka, TakayoshiAbe, ShinjiOtsuki, SatoruMiyake, KuniakiMasumoto, YoshindoOno, Shigeyuki
Austempered Materials and their Applications to Drive Line and Suspension Components2000-01-25639/11/2000
The Austempering process is a high performance heat treatment that, when applied to ferrous materials, produces components that, in many cases, have properties superior to those processed by conventional means. The Austempering processes include: Austempered Ductile Iron Austempered Gray Iron Austempered Steels and Powdered Metals Carbo-Austempered™ Steels Austempered Ductile Iron (ADI) has an exceptionally high strength-to-weight ratio with good fatigue strength and fracture toughness. In fact, with strength three times greater than that of aluminum with only two and a half times the density, ADI can replace aluminum at equal weight for a substantial cost savings. Austempered Gray Iron (AGI) has an excellent combination of noise damping, wear resistance and thermal conductivity. It has received a great deal of attention as diesel engine manufacturers increase cylinder pressures to meet ever more stringent exhaust requirements. Austempered Steels exhibit remarkable fatigue strength and toughness at hardnesses exceeding 38 Rc. They also resist hydrogen embrittlement during plating. High density, powdered metal parts do not crack during heat treatment. Carbo-Austempered™ Steels exhibit low cycle, high load fatigue performance that is 40 to 70% better than that of comparably carburized and hardened components. Carbo-Austempered™ Steels can demonstrate an order of magnitude greater impact strength than carburized and hardened steels.
Keough, John R.
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