Browse Topic: Universal joints
The customer perception of ride comfort with vehicle performance is the most important aspect in a vehicle design. The ride comfort and vehicle performance are influenced by driveline components i.e. propeller shaft phase angle, inclination angle and critical frequency of the driveline system. The optimization of the driveline system is essential to ensure the efficient and smooth power transfer. Propeller shaft is one of the critical components in the driveline to influence the vehicle performance. Propeller shaft characteristics influenced by several factors like vehicle max torque, propeller shaft joint type, materials properties, UJ phase and inclination angle and shaft unbalance value. The optimization of the above parameter within the tolerance limit enables to meet the required performance standard. Various methodologies are available to optimize these parameters to enhance the vehicle performance and comfort leads to customer satisfactions. This study focuses on the analytical optimization of the propeller shaft’s universal joint (UJ) phase and inclination angle and validated at vehicle level. An analytical model was employed to evaluate the velocity fluctuations across the full rotation of the propeller shaft by considering the different UJ phase angles (0° − 360°) and inclination angles (1° − 5°). It was observed from the study that optimization of these parameter improves the vibration performance and decreases the velocity fluctuations. The results shows that the well optimized propeller shaft will enhance smoothness in the driveline systems, reduction in NVH levels, vehicle performance and ride comfort. This study suggests the importance of the precise geometry alignment in driveline design and provide the further refinement methodology.
This paper presents a comprehensive methodology for replicating and quantifying the clicking-noise phenomenon occurring between Generation 3-wheel hub bearings and Constant Velocity Joints (CVJ), particularly in electric vehicles (EVs) where quiet operation makes this noise more noticeable. The study focuses on characterizing the system through contact pressure and distribution measurements, alternating torque tests, and advanced NVH (Noise, Vibration, and Harshness) data processing. The methodology includes detailed descriptions of the physical phenomena, driving conditions generating the noise, and the specific test setup used to simulate real-world conditions. The NVH analysis make use of high-pass filtering techniques to isolate clicking-noise events from background noise, ensuring accurate identification and quantification. Candidate solutions are assessed based on their ability to mitigate clicking noise through the utilization of inherent system components. The results demonstrate significant noise reduction improvements, highlighting the advantages of surface modifications in enhancing contact surface characteristics. This paper provides insights into testing and analysis processes, offering a robust framework for future studies aimed at mitigating NVH issues in automotive applications. The findings underscore the potential of innovative surface treatments in improving the acoustic performance of wheel hub bearing systems, contributing to the development of quieter and more reliable EVs.
Based on the particularity of the racing field of the Baja SAE China, the Baja Racing Team of our university has adopted rzeppa universal joint for vehicle design and field competition in the semi-axle parts of the race car in previous years. In view of the complex conditions of the Baja Competition, such as gravity test, climb test, handling test, endurance test, etc., it is necessary to optimize and develop a more convenient maintenance model. Installation and use of better performance, more suitable for off-road conditions of the shaft. In this paper, based on the development dynamics of automobile axles and the transverse comparison of various axles, a kind of telescopic cross-shaft universal joint axles is designed by using CATIA software to model and simulate kinematics and dynamics by using ANSYS software. At the same time, the stress and strain of the model are continuously optimized according to the change of axle wheel Angle and the torque matching of Baja Racing. The object rotation experiment is designed, and the transmission efficiency of the universal joint of the cross shaft is simulated and analyzed by MATLAB. According to the analysis data and experimental test, the results show that the transmission efficiency, reliability and maintainability of the cross shaft universal joint can fully meet the actual field conditions of the Baja Competition. In addition, this paper also puts forward the optimization scheme and suggestions for improving the transmission efficiency, extending the life and improving the durability of the cross shaft universal joint which may need further research.
1 Rear wheel drive vehicles have a long driveline using a propeller shaft with two universal joints. Consequently, in this design usage of universal joints within vehicle driveline is inevitable. However, the angularity of the driveshaft resulting from vertical oscillations of the rear axle causes many torsional and bending fluctuations of the driveline. Unfortunately, most of the previously published research work in this area assume the propeller inclination angle is constant under all operating conditions. As a matter of fact, this assumption is not accurate due to the vehicle body attitudes either in pitch or bounce motions. Where the vehicle vibration due to the suspension flexibility, either passive or active type, exists. Moreover, the relative motion between the body and the wheel make this virtualization is so far from the realty in real ground vehicles In this research work, the hydro-pneumatic limited bandwidth active suspension system with wheelbase preview control is designed to investigate how the active suspension design affects torsional and bending fluctuations of the driveline in comparison with passive suspension. Accordingly, a half car mathematical model with four degrees of freedom ride vibration coupled with the driveline torsional model is constructed and used for these investigations. The results are generated with two control strategies for the limited bandwidth active suspension, the first one emphasizes on ride comfort and the other emphasizes road holding parameters. On the other hand, two road excitations are used to test the model. The results showed that the virtualization of driveline angularity constant is not suitable for ground vehicle simulation and design. The suspension system type has a significant effect on torsional and bending fluctuations of the driveline. For the limited bandwidth, active suspension type with wheelbase preview control proposed in this work a significant improvement is achieved, in comparison with conventional passive suspension system, through reducing the interaction between the vehicle body vertical vibration and driveline torsional vibration.
The breaking torque is an essential property that identifies the strength of driveshafts under high torque loads. In the breaking torsion test, the constant velocity joint of the driveshafts is usually loaded slowly at a very slow rotating speed under a specific joint angle until it breaks. Under different joint angles, the Rzeppa type constant velocity joint, namely ball joints (BJ), will break at different positions and with different torques. Common results of fracture position include the shaft of the outer race, the shell of the outer race, and the cage column. Simultaneously, the plastic deformation caused by compressive stress occurs at the specific position of the ball track and the cage. In order to analyze the failure reason of the ball joint under a larger joint angle, the quasi-static finite element simulations and test methods are used to analyze the damage caused by stress distribution based on material properties. At the same time, through simulation analysis, the displacement and contact of internal parts can be used to find out the reasons for the imbalance of internal parts.
Multi-body dynamics simulation is widely used in the dynamic research of constant velocity joints (CVJ). Useful kinematic and dynamic conclusions can be obtained from simulations to replace part of the test process and reduce test costs. In this paper, multi-body dynamics parameterized (MBDP) models of the high-efficiency constant velocity joints are proposed in the software of ADAMS. A friction model and Hertz contact theory are applied to describe the contact status. And the torque transmission efficiency of the kind of high-efficiency CVJ is calculated through the MBDP model. Bench tests of torque transmission efficiency are carried out on the CVJ to verify the calculation accuracy of the multi-body dynamics model. And the test result of high-efficiency joint shows an excellent behavior for efficiency when compared with BJ. With the verified parameterized model of the high-efficiency joint, this paper analyzes the theoretical basis for the high transmission efficiency of the high-efficiency joint from the aspect of contact force and friction. And besides, the response surface method (RSM) is used to analyze the influence of the dimension parameters on the torque transmission efficiency of the high-efficiency joint. The dimension parameters such as pitch circle diameter (PCD), pressure Angle, similarity are considered to obtain a response surface prediction model, including six different factors. In addition, Analysis of Variance (ANOVA) and optimization are carried out through the RSM model to evaluate the importance of each dimension parameter on torque transmission efficiency, which is of great significance for the design of constant velocity joints.
During the operation of the automotive drive shaft system, the ball-type universal joint will generate a secondary torque, which will affect the torque transmission of the automotive drive shaft system and the comfort of the automobile. Under the influence of the internal friction of the ball-type universal joint, the secondary torque generates a torque component on the plane where the working angle is located and the plane perpendicular to the working angle. To effectively calculate and analyze the secondary torque, this paper establishes a multi-body dynamic model of the ball-type universal joint. At the same time, the secondary torque of the ball-type universal joint is measured by the NVH multi-function test bench, which verifies the validity of the multi-body dynamic model. In order to improve the analysis efficiency of the secondary torque, a proxy model of the secondary torque of the ball-type universal joint is established based on the multi-body dynamic model. Through the proxy model, the influence of contact angle, conformity value, offset, friction coefficient, and the interference fit between ball and cage window on the secondary torque is analyzed. Using the global sensitivity analysis method of partial derivatives, the sensitivity analysis of the proxy model is carried out, and the degree of influence of each influencing factor on the secondary torque is further determined. According to the results of sensitivity analysis, this article gives measures to optimize the secondary torque.
Idle shake is an important NVH attribute. Vehicles with good NVH characteristics are designed to perform excellent in IDLE and SHAKE conditions. Typically, tactile vibrations at idle are measured at the driver seat and steering wheel. Vibrations caused by engine excitation at idle are passed through several paths to the body structure. The dominant paths being the engine mounts and the half-shafts, either one of them or both can be a major factor influencing the perceived idle vibration in a vehicle. In the past, modeling the half-shafts accurately has been a challenge and often time has been ignored because of modeling complexity. This has led to idle CAE predictions not correlating with test data. The aim of this paper is to describe a finite element modeling method of half-shaft to predict idle vibrations levels. The proposed model includes all the major components of a physical half-shaft: the main shaft and the two constant velocity (CV) joints, modeling of two distinctly different types of CV joints is presented. The first CV joint type is Rzeppa CV joint and the second is Tripod CV joint. The connections between the main shaft and the two joints are represented by linearized elastic springs, the stiffness values were calculated using contact theory and infinitesimal elasticity. The stiffness calculations include the effect of half-shaft angle, applied nominal torque and joints orientation relative to the shaft. The CV joints stiffness variation with applied nominal toque are highly non-linear functions. Furthermore, the half-shaft angle has a nonlinear relationship with the CV joint stiffness; these relations are captured in the proposed method. Since the vehicle idle is at a particular mean toque and half-shaft angle, the proposed method demonstrates a linearization technique to develop a linear model that can be used in linear full vehicle idle model. The vehicle level results show good correlation. For further verification, at the subassembly level, a test fixture was developed and standalone half-shaft assembly was tested. The measured vibrations were compared with those obtained from the finite element model under the same boundary conditions and excitation and a good correlation was observed.
It has been previously shown that a detailed representation of the half-shaft correlates with test data. Developed detailed half-shaft models have shown improvement in capturing the half-shaft path at vehicle idle condition. Since the detailed half-shaft model needs to capture many components and requires detailed solid geometry for each component represented, full CAD model from half-shaft supplier or part scanning is required. Furthermore, despite the availability of CAD geometry, the detailed half-shaft will require solid meshing of the CV joints, the shaft, linearized springs and manual creation of the complex coordinate systems for orientation of contact points. This paper proposes an automated method to reduce the half-shaft model to a semi-elastic rigid body elements model with linearized spring components. The simplified model reduces the modeling time by eliminating solid meshing of components and automating complex coordinate system development without losing accuracy. Typically, the vehicle idle is in low frequencies range [f < 50 Hz] and this implies that most of half-shaft components will not have flexible modes at this frequency range. This theory and associated method was put on test by creating a simplified model and comparing the results to detailed half-shaft model and test data. The results show close correlation with both test and detailed half-shaft model. The simplified model was developed with a computer program and the rapid development of many half-shafts with basic measurements is possible. The simplified model limitation is in the configuration and type of half-shaft; the simplified model program can develop a particular family of half-shafts. Furthermore, for any special type of half-shaft, it needs to be modeled as detailed half-shaft. Simplified half-shaft provides reliable rapid development of half-shaft models for idle condition with reasonable accuracy.
This paper presents theoretical calculation, analysis and simulation (validation and verification) of driveshaft torsion vibration. The vibration measurement validation verification has been carried out on vehicle (4x2) having four cylinder engine 85kw@2800 rpm and six speed manual transmission for getting correlation between values of theoretical calculations and CAE results. This analysis has been done in order to achieve vehicle good performance in terms of driving comfort as well as smooth functionality with zero vibration frequency at high speed. The propeller shaft series selection and refinement has been done using theoretical iteration with operating angle of prop shaft which exits in between the universal joint planes. A frequency of vibration analysis has evaluated at different propeller shaft layout and duty cycle. The vibration performance predictions for vehicles with these design is rigorously done. The required parameters are recorded, compared in tabulated form shown in graphical way. The lowest operating angle of drive shaft design leads to optimize the vibration and provide better overall vehicle performance at different speed. An effective selection of drive shaft layout has been done by doing iterations on operating angle of universal joint. Thus the selected operating U-joint’s angles are input into actual drive line layout design to make it more realistic at zero vibration amplitude. The data is obtained by number of iteration done on vehicle validation as per duty cycle.
For higher mileage vehicles, noise from contaminant ingress is one of the largest durability issues for wheel bearings. The mileage that wheel bearing sealing issues increase can vary due to multiple factors, such as the level of corrosion for the vehicle and the mating components around the wheel bearing. In general, sealing issues increase after 20,000 to 30,000 km. Protecting the seals from splash is a key step in extending bearing life. Benchmarking has shown a variety of different brake corner designs to protect the bearing from splash. This report examines the effect of factors from different designs, such as the radial gap between constant velocity joint (CVJ) slinger and the knuckle, knuckle labyrinth height and varying slinger designs to minimize the amount of splash to the bearing inboard seal. This report reviews some of the bearing seal failure modes caused by splash. This study also discusses the test methodology to confirm the robustness of the various designs and provides information on the effectiveness of different features to protect the corner from splash.
Intermediate shaft assembly is used to connect steering gear to the steering wheel. The primary function of the intermediate shaft is to transfer torsional loads. There is a high probability of noise propagating through the Intermediate shaft to the driver. The current standard for measuring the noise is by performing vehicle level subjective evaluations. If improperly clamped at either of the yokes, a sudden change in the direction of the torsional load on the Intermediate shaft can generate a displeasing noise. Noise can also be generated from the constant velocity joint. Intermediate shaft noise can be measured using a microphone or can be correlated to acceleration values. The benefit of measuring the acceleration over sound pressure level is the reduction of complexity of the test environment and test set up. The nature of the noise in question requires the filtering of low frequency data. This paper presents a new test procedure that has been developed by General Motors. The test requires the steering system to be setup in the nominal vehicle position. The steering system is loaded at the inner tie rod while acceleration levels are measured at different locations. As a function of the steering system, the linear tie rod loads are converted to torsional loads on the Intermediate shaft. The torsional loads acting on the intermediate shaft provide the necessary excitation for the displeasing noise to occur.
With the constant evolution of vehicle systems becomes increasingly challenging the Components project. The demand for mass and cost optimization in a challenging project schedule scenario generates a great challenge to the engineering teams, who look for design and development methods more assertive. In order to reduce the risk of failure, testing time and design cost, simulation tools are being increasingly used. A major challenge in the component project for trucks and buses is the knowledge of the real loads that the components are subjected. In the case of propeller shaft bearings several factors should influence the magnitude of the efforts. The biggest influent factors that has been studied and discussed widely for many years are the torque and joints angles. The “SAE Universal joint and drive shaft design manual” depicts masterfully some formulations to determine the bearing efforts considering effects of geometry and torque, however, with the practical experience, we are faced in some specific situations, with components lifetime lower than expected and even with components plastically deformed demonstrating that the real efforts were higher than the initial design consideration. In vehicle tests we observed that the suspension presents high deformation on abrupt maneuver and that the effect of modifying the geometry should be further studied. The suspension movement occurs mainly for 2 reasons; the torque from engine that causes wind up on the springs and the load transfer that affects the spring deflection. To study the rear suspension geometry changes influence in propeller shaft bearing efforts a multibody model was created allowing the comparison of a vehicle with flexible suspension with a pseudo vehicle with rigid suspension. In this way we can through this study to identify the contribution of the suspension flexibility on propeller shaft bearings efforts getting more suitable design criteria for these components.
Driveshafts are composed of a transmission side joint, wheel side joint, and shaft which connect the two joints. The Rzeppa type constant velocity joint (CVJ) is usually selected as the wheel side joint of a drive shaft for front wheel drive automobiles. Due to recent needs of fuel efficiency and lighter weight for vehicles, it is necessary to reduce the joint size and improve the efficiency of a CVJ. In order to reduce the weight, solving tribology details for long life under high contact pressure is an important issue for developing a CVJ. It is difficult to understand the characteristics of a contact surface, such as relative slip velocity or spin behavior, because the outer race, inner race, cage, and balls, act complicatedly and exchange loads at many points. Meanwhile, after joint endurance tests, ball spalling marks at pole of the ball are sometimes observed. Simulating ball rotational behavior and solving the formation mechanism of such phenomena could contribute to joint durability and joint efficiency improvement. In this paper, ball rotational behavior, is simulated using a multibody dynamics approach including stick slip friction force model that is more accurate than previous. This model enables simulation of ball angular velocity. Through multipoint measuring and graphical analysis, the experiment proves an error of 15% in the simulation result.
EcoCAR 3 is a university based competition with the goal of hybridizing a 2016 Chevrolet Camaro to increase fuel economy, decrease environmental impact, and maintain user acceptability. To achieve this goal, university teams across North America must design, test, and implement automotive systems. The Colorado State University (CSU) team has designed a parallel pretransmission plug in hybrid electric design. This design will add torque from the engine and motor onto a single shaft to drive the vehicle. Since both the torque generating devices are pre-transmission the torque will be multiplied by both the transmission and final drive. To handle the large amount of torque generated by the entire powertrain system the vehicle's rear half-shafts require a more robust design. Taking advantage of this, the CSU team has decided to pursue the use of composites to increase the shaft's robustness while decreasing component weight. The project is meant to explore composites manufacturing techniques and their use in the automotive industry. This paper will discuss the design and manufacturing of a composite half-shaft and the integration of a constant velocity joint (CVJ) for application in a hybrid electric Chevrolet Camaro. It will focus on the design process, particularly on design for composites manufacturing and the CVJ-shaft interface, where metal, carbon fiber composites, and lubricant will meet. The paper will detail the design for composites manufacturing to reduce manufacturing time and cost as well as validate the design through analysis techniques. Finally it will discuss the feasibility of implementing carbon fiber half shafts in high performance consumer vehicles, such as the Chevrolet Camaro.
Drivelines used in modern pickup trucks commonly employ universal joints. This type of joint is responsible for second driveshaft order vibrations in the vehicle. Large displacements of the joint connecting the driveline and the rear axle have a detrimental effect on vehicle NVH. As leaf springs are critical energy absorbing elements that connect to the powertrain, they are used to restrain large axle windup angles. One of the most common types of leaf springs in use today is the multi-stage parabolic leaf spring. A simple SAE 3-link approximation is adequate for preliminary studies but it has been found to be inadequate to study axle windup. A vast body of literature exists on modeling leaf springs using nonlinear FEA and multibody simulations. However, these methods require significant amount of component level detail and measured data. As such, these techniques are not applicable for quick sensitivity studies at design conception stage. This paper bridges this gap in the literature by developing a spring model at the conceptual phase using the multibody dynamics (MBD) tool Adams based on a minimal parameter set to define leaf geometry and profile. Linear Timoshenko beam theory is employed to model the leaves thus accounting for the beam cross-section rotation which facilitates simulation of bending and shear effects. This is essential for simulating spring seat angle changes during acceleration and braking under different vertical loads. A mono leaf spring case study is presented to demonstrate the modeling capability along with a sensitivity study to provide insights on factors that affect axle windup. The effect of drive torque and longitudinal load on the windup behavior of both symmetric and asymmetric springs is demonstrated. Two-stage symmetric and asymmetric spring models are validated against test data for windup. This methodology will help develop spring simulations quickly during the design conception phase and thereby provide valuable information regarding the response of integrated vehicle systems. This in turn will help drive the design from an early stage thereby preventing expensive and time-consuming design changes later in the product development phase.
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.
This study is inspired by the calculations and validations required for front wheel drive (FWD)-halfshaft joint selection. To increase design efficiency with decreased response time; a tool is required to validate calculations of strength based on maximum impact torque and endurance life based on corresponding vehicle usage. The tool has been developed to cover both strength and endurance life calculations. It also includes a constant velocity joint (CVJ) size library in order to compare different cases and to be able to see opportunities between different sizes. Validation and correlation has been completed using road load data from actual vehicles and standard load cycle (SLC) rig test results. This study introduces a more efficient methodology that will help the user select a joint that is sized best for strength and cost. After the completion of the study, one can be assured that the joint selected is the proper size-for all kinds of FWD vehicles.
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