Browse Topic: Constant-velocity joint
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.
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.
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.
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.
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.
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.
Prop shafts and differentials have been improved continuously. They are getting even more efficient and more lightweight. But the interface between these two parts looks still the same since more than 50 years what gives us a great chance for improvement. Rear or front axle differentials are currently fitted with a flange. This flange is necessary to connect the prop shaft frictionally with the differential during the final assembly. The substitution of universal joints by constant velocity joints gives the possibility of replacing a flange connection by a compact, lighter screwed connection. This paper will present a new single piece screwed solution which fits perfectly on the demands of modern all- / rear - wheel driven cars.
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.
For 2007, the brand's iconic Wrangler is engineered to be more rugged off-road and more refined on it. Over an 8.6-mi (14-km) stretch of the Rubicon Trail in the Sierra Nevada Mountains, which took more than 4 h to traverse, the new 2007 Jeep Wrangler proved to be every bit as capable, if not more so, than its predecessors. Perhaps more impressive is that the sixth-generation SUV handled just as capably on the paved roads winding around Lake Tahoe. Jeep engineers focused on more than 50 functional objectives-from ground clearance to articulation to ride and handling-for the new Wrangler lineup. One of the main engineering features that contributed significantly to the improved ride and handling characteristics on such varied surfaces is a new fully boxed frame that is 100% stiffer in bending and 50% stiffer in torsion.
Existing VDR mechanisms have not progressed beyond the ground test experimental stage partially due to their inability to achieve the weight, reliability and maintainability requirements for practical aircraft application. Recent advancements in digital flight control systems and Health Usage Monitoring however can be applied to make a Variable Diameter Rotor (VDR) mechanism practical. Current published VDR design concepts do not integrate with existing rotor hub designs since their mechanisms occupy the space normally used by the rotor hub's structure and constant velocity joint. Many of these designs require a rigid hub configuration to maintain alignment of their VDR mechanism gearing. By using separate differential planetary rotary transmissions at each blade and interconnecting them with flexible timing belts, the mechanism described in this paper integrates with most existing rotor hub design configurations. This paper studies the application of system control and mechanical power transmission technologies to create a practical VDR mechanism for the BA609 three bladed rotor. A historical review of VDR studies and experimentation performed by Bell between 1962 and 1971 provides an introduction to the technical issues facing the development of a practical VDR mechanism design.
Automakers have had-and continue to seek-greater use of new and advanced metals, especially for light trucks. Just because a given metal scores an application zone in one model year does not mean the material will continue to log assignment time in the future. If a better option comes along, that material becomes the odds-on favorite to become the application winner. But what makes a given metal a worthy choice?
Items per page:
50
1 – 50 of 78