Browse Topic: Driveshafts
Automotive driveline imbalance is a result of rotating components or assemblies being manufactured with their centers of mass not being coincident with their centers of rotation. For vehicle mass production, an end-of-line (EOL) driveline balancing process may be required, depending on vehicle sensitivity and component control costing. In this investigation, the process and facility design for an EOL automotive driveline balancing process is outlined, including important considerations in the measurement configuration of the balancing facility. Initial results from prototype vehicle testing with conventional influence balancing techniques, based on commercially available equipment, are given. The role of the influence coefficient in the balancing process and of car-to-car variability in the influence coefficient were investigated. An equation for the influence coefficient was derived, providing an improved understanding of the nature of the influence coefficient, along with sources of
This SAE Recommended Practice is intended for hubs and spoke wheels used on Class 6, 7, and 8 truck/truck-tractor non-powered front axles, powered and non-powered rear axles and trailer axles, for which bearing setting is manually adjusted. Assemblies using spacers to control bearing preload and endplay may differ in geometry and bearing componentry
This ARP applies to turbine engines that are to be used in helicopters. It provides the engine designer guide lines in achieving a satisfactory turbine engine drive shaft connection
This SAE Information Report provides test methods and determination options for evaluating the maximum wheel power and rated system power of vehicles with electrified vehicle powertrains. The scope of this document encompasses passenger car and light- and medium-duty (GVW <10000 pounds) hybrid-electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), and fuel-cell electric vehicles (FCEVs). These testing methods can also be applied to conventional ICE vehicles, especially when measuring and comparing wheel power among a range of vehicle types. This document version includes a definition and determination methodology for a rated system power that is comparable to traditional internal combustion engine power ratings (e.g., SAE J1349 and UN ECE R85). The general public is most accustomed to “engine power” and/or “motor power” as the rating metric for conventional and electrified vehicles, respectively. Wheel power will always be a lower-power
This procedure covers vehicle operation and electric dynamometer (dyno) load coefficient adjustment to simulate track road load within dynamometer inertia and road load simulation capabilities
This SAE Aerospace Recommended Practice (ARP) covers specification requirements for a rotary plow with carrier vehicle. The primary use is to cast heavy concentrations of snow approximately perpendicular to carrier vehicles across and away from airport operational areas, such as runways and taxiways. Rotary plows equipped with spot casting, or loading chutes are also used to cast snow in directions through approximately 100 degrees to the left or right of directly in front of the carrier vehicle, and also to load trucks or trailers used to haul snow away from removal area. The term “carrier vehicle” represents the various self-propelled prime movers that provide the power necessary to move snow and ice control equipment during winter operations
Accurate determination of driveshaft torque is desired for robust control, calibration, and diagnosis of propulsion system behaviors. The real-time knowledge of driveshaft torque is also valuable for vehicle motion controls. However, online identification of driveshaft torque is difficult during transient drive conditions because of its coupling with vehicle mass, road grade, and drive resistance as well as the presence of numerous noise factors. A physical torque sensor such as a strain-gauge or magneto-elastic type is considered impractical for volume production vehicles because of packaging requirements, unit cost, and manufacturing investment. This paper describes a novel online method, referred to as Virtual Torque Sensor (VTS), for estimating driveshaft torque based on Machine-Learning (ML) approach. VTS maps a signal from Inertial Measurement Unit (IMU) and vehicle speed to driveshaft torque. The unique advantage is that VTS does not explicitly rely on the first principles
Accelerometers are transducers, or sensors, that convert acceleration into an electrical signal that can be used for airframe, drive, and propulsion system vibration monitoring and analysis within vehicle health and usage monitoring systems. This document defines interface requirements for accelerometers and associated interfacing electronics for use in a helicopter Health and Usage Monitoring System (HUMS). The purpose is to standardize the accelerometer-to-electronics interface with the intent of increasing interchangeability among HUMS sensors/systems and reducing the cost of HUMS accelerometers. Although this interface was specified with an internally amplified piezoelectric accelerometer in mind for Airframe and Drive Train accelerometers, this does not preclude the use of piezoelectric accelerometer with remote charge amplifier or any other sensor technology that meets the requirements given in this specification. This SAE HUMS Accelerometer Interface Specification includes the
This SAE Aerospace Recommended Practice (ARP) is an application guide for fixed and variable displacement hydraulic motors. It provides details of the characteristics of fixed and variable displacement hydraulic motors, architectures, circuit designs, controls, and typical applications. The applications include airborne and defense vehicles with emphasis on high performance applications
With the advent of BS VI regulations, automotive manufacturers are required to innovate the powertrains, fuel systems, exhaust and its after treatment systems to meet the regulatory requirements. The exhaust regulations can be met either by reducing the exhaust gases being generated by the engine (attacking the source) or by treating the exhaust gases in after treatment devices. The choice of the opted system varies with the manufacturer. The after-treatment devices such as catalytic converters are generally mounted in the engine compartment to take advantage of high temperature of exhaust gases to yield the reactions. Such an arrangement imposes a lot of thermal load on the peripheral components such as gearshift cables, bearings, oil seals, driveshafts etc. Thermal shields or thermal sleeve are used to address thermal issue and to protect transmission components. System level validation test requirement of transmission need to be re-visited considering change in environmental
Calibrating a vehicle’s powertrain for dynamic operation needs to focus on efforts to mitigate the risks of thermal overload which may arise in the stator or rotor components of an e-motor. Risks also may arise for expected NVH or durability targets, with torque and torque “oscillations” acting as primary sources for the vehicles’ NVH behavior. Both topics, temperature measurement of stator and rotor as well as dynamic torque measurements of the powertrain’s drive shaft are addressed with examples demonstrating the sensors applications in normal test bed and vehicle configurations
The driveshafts can be an important contributor to vehicle interior noise including low-frequency (booming) noise where the vibrations, originating in the powerplant, travel to the vehicle body through the driveshafts. A suitable Key Performance Indicator (KPI) for the driveshaft performance is the transmissibility, which is an output/input acceleration ratio and can be used to describe the amount of vibration transferred from the inboard to the outboard joint of the driveshaft. This paper introduces a simple physical model of the driveshaft transmissibility able to support the development and evaluation of the driveshaft and to estimate the effectiveness of countermeasures such as a dynamic damper. The model is validated through comparison with on-vehicle measurements. The proposed approach offers ease of use, low computational cost and clear relation of the measured transmissibility with the system’s physical properties. Good accuracy can be obtained for the booming noise range
This SAE Aerospace Information Report (AIR) provides details of how to perform hydraulic system calculations using equations that incorporate the metric International System of Units (SI
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
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
A ball joint is an important component of the automotive drive shaft system, as well the contact stress inside the ball joint is an important optimization goal in the design of ball joints. At present, the analysis of the contact stress inside the ball joint mainly focuses on the static contact stress analysis. The static contact stress analysis, however, cannot reflect the change of the contact stress inside the ball joint. In order to analyze the contact stress of the ball joint more effectively, a hybrid flexible and rigid bodies dynamics (HFRBD) model of the ball joint for studying the dynamic contact stress inside the ball joint is proposed. In the HFRBD model, the balls are regarded as the rigid body, while the cage, the inner race and the outer race are regarded as the flexible body. The contact parameters of the contact pairs in the model are determined on the basis of Hertz contact theory. Through the destruction test of the ball joint and the numerical example, the
This SAE Aerospace Information Report (AIR) outlines a recommended procedure for evaluation of the vibration environment to which the gas turbine engine powerplant is subjected in the helicopter installation. This analysis of engine vibration is normally demonstrated on a one-time basis upon initial certification, or after a major modification, of an engine/helicopter configuration. This AIR deals with linear vibration as measured on the basic case structure of the engine and not, for example, torsional vibration in drive shafting or vibration of a component within the engine such as a compressor or turbine airfoil. In summary, this AIR discusses the engine manufacturer’s "Installation Test Code" aspects of engine vibration and proposes an appropriate measurement method
This SAE Recommended Practice provides a method to determine the performance characteristics of the hydraulic oil pumps used in automatic transmissions and automatic transaxles. This document outlines the specific tests that describe the performance characteristics of these pumps over a range of operating conditions and the means to present the test data. This document is not intended to assess pump durability
The adequate dimensioning of drive train components such as gearbox, clutch and driveshaft presents a major technical task. The one of manual transmissions represents a special significance due to the customer’s ability of inducing high force, torque and thermic energy into the powertrain through direct mechanical interconnection of gearstick, clutch pedal and gearbox. Out of this, the question about how to capture behavior and strain of the components during real operation, as well as their objective evaluation evolves. Furthermore, the gained insights must be considered for designing and development. As a basis for the examination, measuring data from imposing driving tests are adduced. Therefore, a trial study has been conducted, using a representative circular course in the metropolitan area of Stuttgart, showing the average German car traffic. The more than 40 chosen drivers constitute the average driver in Germany with respect to age, gender and annual mileage. The used vehicle
This SAE Recommended Practice was established to provide an accurate, uniform, and reproducible procedure for simulating use of MD/HD conventional vehicles (CVs) and hybrid-electric vehicles (HEVs), as well as plug-in hybrid-electric vehicles (PHEVs) and battery electric vehicles (BEVs) on powertrain dynamometers for the purpose of measuring emissions and fuel economy. This document does not specify which emissions constituents to measure (e.g., HC, CO, NOx, PM, CO2), as that decision will depend on the objectives of the tester. While the main focus of this procedure is for calculating fuel and energy consumption, it is anticipated that emissions may also be recorded during execution of this procedure. It should be noted that most MD/HD powertrains addressed in this document would be powered by engines that are certified separately for emissions. The engine certification procedure appears in the Code of Federal Regulations, Title 40 §86 and §1065
Characteristics of horizontal hard-bearing balancing machines are described which make such machines suitable for gas turbine rotor balancing
To study the generated axial force (GAF) of the drive shaft system more accurately and effectively, this paper introduces the interval uncertainty into the research focusing on the GAF. Firstly, an interval uncertainty model for calculating the GAF is proposed based on the Chebyshev polynomials and an analytical model of the GAF. The input torque, the articulation angle, the rotation angle of the drive shaft system, the pitch circle radius (PCR) of the tripod joint and the friction coefficient are regarded as interval variables. Secondly, the upper and lower bounds of the proposed GAF model under interval uncertainty parameters are calculated quickly with the vertex method. Then the interval uncertainty optimization of the GAF under uncertainty parameters is performed. The upper bound of the response interval of the GAF is taken as the optimization object. Finally, the proposed model is verified by experiments, while the interval uncertainty analysis and optimization of the GAF are
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
Increased focus on fuel efficiency and vehicle emissions has led the automotive industry to look into low weight alternative designs for powertrain system components. These new design changes pose challenges to vehicle attributes like NVH, durability, etc. Further, the requirement of high power applications produces even more complexities. The present work explains how a potential design change of half shafts driven by a desire to reduce weight and cost can lead to NVH problems caused by half shaft resonances and explains how using multiple dynamic vibration absorbers can solve the issue to meet customer expectation while improving efficiency. With the aid of Finite Element Analysis (FEA) & optimization software, interactions between multiple DVA’s on a system was understood and optimal damper parameters for effective damping was identified. The final DVA design was tested and verified on the vehicle for optimal attribute performance
The knowledge of mechanical behaviour of material is vital for durability prediction and attending initial project requirements. Through the experimental evaluations is possible to measure this behaviour and use it as input in numerical simulations. Temperature changes considerably static and dynamic mechanical properties of materials, particularly in elastomers. This study was motivated to predict the durability under several working temperatures of center bearings rubber cushion of driveshafts that needs to achieve prespecified stiffness and durability parameters. Standardized specimens were tested in fatigue for experimental investigation of the rubber compound. Durability tests were performed in the final product sample and compared with tests performed in standardized specimens. It was concluded that this approach produces accurate results for fatigue predictions and provided useful equations for practical design applications and reducing product validation time
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
This SAE Standard specifies the nominal dimensions and tolerances which affect the interchangeability between companion flanges and mating parts. The flanges covered by this document are designated type A and type S. The type A flanges are equivalent to type A ISO 7646. The type S flanges are equivalent to the type S ISO 7647. Type A is an external (male) pilot construction and type S is an internal (female) pilot construction. These flanges are not interchangeable. Dimensions not specified are left to the discretion of the component manufacturer
This document specifies the main dimensions and tolerances, which affect interchangeability between end yoke earwork for the most common North American used universal joints. Dimensions and tolerances of the mating universal joints are left to the discretion of the universal joint manufacturers. The term “Earwork” refers to the configuration and geometry defining end yoke connections directly provided for universal joint cross attachment of drivelines. Earwork for certain styles of universal joint connections and flange connections have for a long time been proprietary to certain manufacturers. Over years of usage, proprietary rights have expired and the industry, as a whole, has used these earworks as standard. In an effort to tabulate some of the long established practices, the following SAE Recommended Practice has been compiled. Manufacturers do from time to time, as the need arises, change tolerances or fits to better enhance component performance. This document has been prepared
Product for which data is to be available is for class 6 and larger, i.e., gross vehicle weight > 9.6 kg (19 500 lb
The increased demand in fuel economy and the reduction of CO₂ emissions results in continued efforts to downsize engines. The downsizing efforts result in engines with lower displacement as well as lower number of cylinders. In addition to cylinder and displacement downsizing the development community embarks on continued efforts toward down-speeding. The combination of the aforementioned factors results in engines which can have high levels of torsional vibrations. Such behavior can have detrimental effects on the drivetrain particularly during the development phase of these. Driveshafts, couplings, and dynamometers are exposed to these torsional forces and depending on their frequency costly damages in these components can occur. To account for these effects, FEV employs a multi-body-system modeling approach through which base engine information is used to determine optimized drivetrain setups. All mechanical elements in the setup are analyzed based on their torsional behavior
Driveshafts are one of the most important components in power-train system in vehicle as it transfer torque generated from engine to wheels in high speeds. As a driveshaft is in rotating condition vibration problems can be observed by resonance or external force. The generated vibration problems in vehicles cause discomfort to drivers whenever they are driving. To solve these problems, there have been many attempts to control such generated vibration in vehicle. In this study, vibration control system for driveshaft has been proposed to reduce the generated vibration. The smart damper for the system is designed considering to be implemented in driveshaft with quick response and a compact size. The damper is consists of electromagnets so it can response relatively quickly compared to other damping system. When a driveshaft reaches to its natural frequency, vibration control system with the damper is activated to minimize the vibration as it shifts its natural frequency region. The test
This SAE Recommended Practice is intended for use in testing and evaluating the approximate performance of engine cooling fans. This performance would include flow, pressure, and power. This flow and pressure information is used to estimate the engine cooling performance. This power consumption is used to estimate net engine power per SAE J1349. The procedure also provides a general description of equipment necessary to measure the approximate fan performance. The test conditions in the procedure generally will not match those of the installation for which cooling and fuel consumption information is desired. The performance of a given fan depends on the geometric details of the installation, including the shroud and its clearance. These details should be duplicated in the test setup if accurate performance measurement is expected. The performance at a given air density and speed also depend on the volumetric flow rate, or the pressure rise across the fan, since these two parameters are
This SAE Recommended Practice covers the application of hydraulic brake hose (as defined by current issue of SAE J1401) as used to provide a flexible hydraulic connection between wheel end or axle brake system components on motor vehicles
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