Analysis of the Gear Shift Mechanisms by R-R Chart Method

<div class="section abstract"><div class="htmlview paragraph">Automatic transmission (AT) is a complex hydroelectromechanical system, since it consists of hydraulic, electrical and mechanical parts.</div><div class="htmlview paragraph">On cars produced by “UzAuto Motors” mainly AT of the 6T family, 6-speed AT family GM: 6T30, 6T40, 6T45, 6T50 “Hydra-Matic” are used.</div><div class="htmlview paragraph">Production of parts of these transmissions is carried out both at American GM plants and at GM plants in China and Korea.</div><div class="htmlview paragraph">The differences between AT 6T30/6T40/6T45/6T50 are in the thickness of the output chain and in the planetary gear, in the sizes of some other units and the housing itself. But the differences are much more influenced by the settings of the transmission unit, which select operating modes with different engines so as not to overload the thinnest places of the automatic transmission.</div><div class="htmlview paragraph">Automatic transmissions 6T30, 6T40, 6T45, 6T50 have the ability to manually shift gears and activate the “kickdown” mode (for quick acceleration of the car, when you sharply press the gas “all the way” it makes the automatic transmission downshift, and sometimes by two steps).</div><div class="htmlview paragraph">The operation of the transmission is controlled by various electronic systems that are responsible for the operability and structural integrity of the gearbox.</div><div class="htmlview paragraph">Failure of the automatic transmission can occur as a result of one or a combination of malfunctions of the following parts: in the torque converter; in the mechanical part of the gearbox; in the hydraulic part of the control system; one or more clutches of the gearbox; in the electrical part of the control system; in the electronic control unit.</div><div class="htmlview paragraph">The authors of the work investigated and determined the occurrence of malfunctions and failures depending on the temperature of the working fluid of the automatic transmission of a passenger car.</div><div class="htmlview paragraph">Also, the dependence of the resource of the automatic transmission on the temperature of the hydraulic fluid was obtained. High-quality diagnostics of the automatic transmission and its control system can in many cases save the car owner from expensive repairs: <ul class="list disc"><li class="list-item"><div class="htmlview paragraph">without thorough diagnostics, the automatic transmission cannot be subjected to routine or major repairs. Only on the basis of diagnostic information can a conclusion be made about the technical maintenance or repair of the automatic transmission;</div></li><li class="list-item"><div class="htmlview paragraph">based on real experience of operating passenger cars equipped with automatic transmission, we recommend changing the oil every 35000 miles under operating conditions in Tashkent. We also recommend conducting diagnostics of the automatic transmission every 12500 miles of the car's mileage.</div></li></ul></div></div>

More and more planetary gear mechanisms are being used in Hybrid Electric Vehicle (HEV) as multi-energy coupling mechanisms because of their compact structure, high transmission efficiency and strong load bearing capacity. In order to get all the planetary gear schemes that satisfy the requirements of topological characteristics and select the optimal scheme for Hybrid Electric Vehicle Planetary Gear Coupling Mechanism (HEV-PGCM) as the references for the following analysis and structure design. Firstly, a variety of HEV-PGCM schemes with required topological characteristics are designed by applying the Creative Design Method. Secondly, according to the design requirements of planetary gear transmission and HEV power coupling mechanism, combined with Matrix Theory, the scheme evaluating indicators and method for HEV-PGCM are presented and used for scheme analysis and optimal selection. The results indicate that this method is general for common use and it can provide reference schemes for the following structure parameter design and analysis of HEV-PGCM.

<div class="section abstract"><div class="htmlview paragraph">This paper presents a methodology to represent automatic transmission clutch-to-clutch shift dynamics with a two degree of freedom, lumped inertia model. The method of reducing the automatic transmission to a lumped, two inertia model as a function of shift and input shaft acceleration is detailed using a full kinematic representation of the automatic transmission. For a given clutch-to-clutch shift maneuver there are two dependent equations that utilize the two lumped inertias and represent the response of the transmission system from input to output shaft. Applicability of the method is shown for planetary automatic and layshaft dual clutch transmissions. Typical clutch-to-clutch shift maneuvers are illustrated with the two inertia model for power on upshifts and downshifts. The simplification of automatic transmission shift dynamics using this method enables rapid synthesis of a given transmission powerflow for estimation of shift quality potential, required clutching torques, inertia phase engine torque intervention and output torque through all phases of a shift event.</div></div>

<div class="htmlview paragraph">An automatic transmission planetary gear fatigue test is used to screen lubricant performance of various automatic transmission fluids. The key use of this test is to assess the ability of a lubricant to extend or limit planetary gear system fatigue life. We study the fatigue behavior in this test and find the major failure modes are tooth macropitting, and macropitting-related tooth fracture of the sun and planetary gears (short and long pinion gears). Micropitting appears to be responsible for these gear failure modes. Macropitting is also seen on the shafts and needle rollers of the bearings. Gear tooth fracture appears to have originated from the surface as a secondary failure mode following macropitting. Bearing macropitting is initiated by geometric stress concentration. Bending fatigue failure on the sun and planetary gears also occurs but it is not a micropitting-initiated failure mode. Tooth macropitting and the related tooth fracture appear to occur independently from bearing macropitting. As expected, the directions of micro- and macro-crack propagations in mating gears go in opposite directions.</div>

<div class="section abstract"><div class="htmlview paragraph">This paper introduces a new concept for the identification of automatic transmission gear trains. It describes the use of kinematic graphs to separate the topological structure of the gear train from its function. Using this method, it has been shown that known epicyclic automatic transmission gear trains can be classified in a systematic and unbiased manner. This procedure allows transmission mechanisms which have different gear arrangements to be compared on a uniform basis so their similarities and differences can be identified.</div><div class="htmlview paragraph">It has been shown previously that there are 80 non-isomorphic displacement graphs from which all of the six-link, one-degree-of-freedom gear trains can be constructed. Here we show that there are seven non-isomorphic displacement graphs from which all epicyclic-type automatic transmission gear trains with up to six links and with four or more coaxial links can be derived.</div><div class="htmlview paragraph">In this paper, epicyclic-type transmission gear trains were searched, and their corresponding schematic and graph representations were classified. We found that the known transmission gear trains with six links all belong to these seven displacement graphs.</div></div>

<div class="section abstract"><div class="htmlview paragraph">The worldwide increasing acceptance and success of modern automatic transmissions in passenger cars is based on innovative technology, driving comfort, shifting dynamic and - most important - fuel consumption reduction.</div><div class="htmlview paragraph">New concepts are facing the challenge of further improvements in internal efficiency and very tough future goals on CO2 emissions in connection with more sophisticated gasoline and diesel engine technologies. Based on the competition and current diversity in automatic transmission concepts, high investments in production facilities must be taken also well into account when thinking about follow-up technologies of installed 8-speed and 9-speed technologies. This must also be considered for the different demands in regions and markets.</div><div class="htmlview paragraph">So, how may a successful automatic transmission system look like in 2020 and beyond? Do we have even more gears than the current 8-speed and 9-speed? Does it make sense to increase the total gear ratio any further? Are there measures to improve the overall mechanical efficiency by several percent? What is the prevailing transmission system: torque converter planetary, dual-clutch countershaft or belt-type stepless transmission? How does the electrification and hybridization of the powertrain in the next years effect the system?</div><div class="htmlview paragraph">This article will give some brief answers on how ZF is planning the future of automatic transmissions and how successful systems should look like.</div></div>

<div class="section abstract"><div class="htmlview paragraph">The parameters determining shift quality control in automatic transmissions are determined as part of the calibration of the transmission control. The resulting control system typically has three components: feedforward control, where the control output is determined before a gearshift; feedback control, where the control output is determined during the gearshift based on sensed feedback; and learning control (adaptation), where the feedforward or feedback controller parameters are modified after the current gearshift has ended and before the next similar gearshift begins. Gearshifts involving the same ratio change are referred to here as similar gearshifts, though such gearshifts may involve differences in other variables such as vehicle speed or engine torque. In most automatic transmissions, gearshifts are controlled by hydraulic clutches, and operating conditions for these clutches may vary widely, requiring a dedicated transmission controller involving significant calibration effort.</div><div class="htmlview paragraph">In the current work, novel model-based methods are used to accomplish feedforward control of gearshifts, involving offline calibration of fill and torque phase control parameters and learning control of the fill phase. Towards this end, a physics-based model of the oncoming clutch involved in an upshift of a production automatic transmission was developed and experimentally validated against test bench experiments for a wide variety of inputs and operating conditions. The resulting model is used to generate a feedforward controller, offline model-based calibration algorithm, and a learning controller that corrects for clutch under-fill and over-fill. The effectiveness of the resulting controller is validated by simulation studies using the experimentally validated transmission hydraulic system model, in conjunction with a powertrain model. In particular, it is demonstrated that the learning controller corrects for initial under- or over-fill error in two to three gearshifts. Convergence and robustness properties, and transient performance of the learning controller are also discussed.</div></div>

<div class="htmlview paragraph">This paper introduces mathematical equations for power loss calculations of major automatic transmission components.</div> <div class="htmlview paragraph">It also presents a theoretical investigation on contributions of each component's power loss to transmission total power losses.</div> <div class="htmlview paragraph">A computer program for automatic transmission efficiency calculation has been developed based on mathematical equations.</div> <div class="htmlview paragraph">Efficiency calculations for the Hyundai A4BF1 electronic 4 speed automatic transmission has been executed in order to validate the program.</div> <div class="htmlview paragraph">The calculated efficiency under various input and operating conditions - such as different input torque & RPM, transmission gear state, ATF temperature, torque converter clutch on/off - showed quite good agreement with the test results.</div>

<div class="htmlview paragraph">An automatic transmission for heavy duty trucks and buses has been developed. Automatically controlled dry clutch and synchromeshed gear transmission make driving easier, while maintaining good fuel efficiency of a mechanical transmission.</div> <div class="htmlview paragraph">The system consideration and design philosophies of the electronic controller are described here, as well as the mechanical hardware for conversion of a manual transmission into a fully automatic transmission.</div> <div class="htmlview paragraph">This transmission control system has not only the functions of an automatic transmission but also driveability and efficiency same as that of a skilled driver by incorporating various kinds of control logics.</div> <div class="htmlview paragraph">It is our fair judgement that this transmission can well meet market requirements in new age.</div>

To obtain the optimal seedling taking trajectory, this study proposed the adjustment of the total transmission ratio curve by using human-computer interaction. On the basis of this design method, a planetary non-circular gear mechanism was designed that can realize the twice unequal amplitude transmission ratio to meet the seedling harvesting requirements. The cubic non-uniform B-spline curve was used to fit the twice unequal amplitude transmission ratio curve, and the transmission ratio was freely distributed in two levels. The seedling pick-up mechanism was designed by controlling the seedling taking track and the corresponding attitude directly through the local section of the total transmission ratio, and the gear pitch curve was directly controlled by the transmission ratio. The kinematics model of the seedling pick-up mechanism was also established. Furthermore, the influence of the total transmission ratio on the seedling picking track, the ratio of the wave crest to the amplitude, and the mechanism parameters were discussed. A human-computer interactive optimization software was developed using Matlab, and a set of optimal parameters for the seedling pick-up mechanism was obtained to meet the transplanting requirements. By using the Adams software, the virtual prototype simulation of the seedling pick-up mechanism was completed, and the idle experiment for the track and attitude of the prototype was conducted through high-speed camera technology. The theoretical, simulated, and experimental trajectories were consistent with each other. Results revealed that the success rate of the seedling picking exceeded 90% when the rotation speeds were 40 r/min, 50 r/min, and 60 r/min, and the qualified rate of the matrix decreased with the increase in rotating speed. Moreover, the number of damaged plants increased with the increase in rotating speed. The experimental results showed that the seedling pick-up mechanism designed using the proposed method demonstrated a good effect and met the required seedling picking performance. Keywords: seedling pick-up mechanism, second unequal amplitude, planetary gear train, seedling picking experiment DOI: 10.25165/j.ijabe.20221501.6168 Citation: Liu J G, Yu G H, Tong Z P, Hua Y. Design and experimental study of a planetary gearing mechanism based on twice unequal amplitude transmission ratio. Int J Agric & Biol Eng, 2022; 15(1): 155–163.

<div class="htmlview paragraph">This paper presents a general discussion of automatic transmission parasitic losses and efficiency characteristics.</div> <div class="htmlview paragraph">Efficiency characteristics of the three major automatic transmission components-pump, torque converter, and gearbox-and their contribution to the transmission total torque losses are examined. A data reduction method for isolating gearbox torque losses from total transmission losses is also described.</div> <div class="htmlview paragraph">The information presented is based on pump, torque converter, and transmission testing performed at SwRI for Ford Motor Company. Test data was used to perform analytical fuel economy benchmarking studies. Testing included 13 transmissions manufactured by American, European, and Japanese manufacturers for 3.0-5.8L truck applications.</div>

<div class="htmlview paragraph">The most common driveline configurations in cars are the standard drive with front longitudinal engine and rear wheel drive and the front-transverse drive with east west installed powertrain as well as all-wheel drive variants derived from these. These driveline configurations are used in different vehicle segments. The transmission systems mainly used today are automatic transmissions with 4 or 5 speeds and manual transmissions with 4, 5 or 6 speeds. A small number of automated manual transmissions (AMT) and continuously variable transmissions (CVT) are in production. Various systems of automated manual transmissions, powershift transmissions designed as double clutch transmissions and toroidal transmissions are currently being developed.</div> <div class="htmlview paragraph">A brief explanation will be given about the structure of all different driveline configurations and the transmission systems will then be considered for specific applications in these different drivelines. The installation situation with transmission structure and space, potential for fuel savings with overall ratio and efficiency, reduction of emissions and noise levels, performance, drive comfort, transmission weight and manufacturing costs are considered as the main aspects within this paper. This leads to an assessment and recommendation for the use of certain transmission systems for the various driveline configurations.</div> <div class="htmlview paragraph">In the future, both 6-speed automatic transmissions and 6-speed manual transmissions will be used on a wider scale with standard drives. The use of continuously variable transmissions will increase for front transverse drive. In the field of manual transmissions the 5-speeds will dominate in front transverse drive applications. The degree of automation will increase in this segment. For torque levels of up to approximately 180 Nm, preference will be given to the use of automated manual transmissions. The range of up to 350 Nm will be predominantly covered by CVT's, five and six-speed automatic transmissions will subsist in the segment above 350 Nm for transverse installation.</div>

<div class="htmlview paragraph"><b>STARTING with the Sturtevant in 1904, transmission developments are reviewed to date. Requirements for successful and satisfactory automatic transmissions are discussed and interpreted in the light of present and future development.</b></div> <div class="htmlview paragraph"><b>Six tables that classify transmissions comprise the nucleus of this part. These tables group the methods of varying the speed; the means of control; the gear engagement or connection; the shifting methods; clutches; and clutch control.</b></div> <div class="htmlview paragraph"><b>THE story of over two million miles of operating experience using the “Mono-Drive” type of automatic transmission on 101 passenger buses in Chicago, is told in the second part of the paper. The mechanical operation of this automatic transmission is explained, and specifications and data are given on the buses in which they are used. A review of the maintenance record of the transmissions concludes the paper.</b></div>

<div class="htmlview paragraph">A new automatic transmission called the CEEMAT (Converter Enhanced, Electronically Managed, Automatic Transmission) has been developed to serve the on/off highway truck market. The CEEMAT was also specifically designed to suit military applications.</div> <div class="htmlview paragraph">The CEEMAT is a unique combination of currently available mechanical transmission products and the power and sophistication of electronic control.</div> <div class="htmlview paragraph">The CEEMAT provides ample ratio coverage with proven reliability. Fuel economy can also be improved because of extended torque converter lockup function and the overdrive ratio.</div>

According to the characteristic formula of planetary gear transmission, by studying the movement and torque transmission of planetary gear mechanism of Automatic Transmission, this paper presents a new method of transmission analysis by use of the matrix. The method established the mathematical model about the coupling form and shift constraint and torque transmission between the planetary lines based on matrix theory. It is generally applicable to the movement and torque calculation of complex planetary gear mechanism.