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    Parameter Optimization of Two-Speed Manual Drive with Automatic Speed Change for Stop Valves
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    A usual two-way clutch cannot rotate at high speed. Therefore, it is not suitable for a device that needs to rotate at high speed. In this paper, we propose a two-way clutch mechanism that can rotate at high speed. A one-way clutch can rotate at high speed in comparison with a two-way clutch. A two-way clutch restricts the transmission-direction of the torque only from the input shaft to the output shaft. The one-way clutch restricts the rotation-direction of a shaft in one direction. In the proposed mechanism, a planetary gear is sandwiched between two one-way clutches. When the rotation direction is changed, the planetary gear moves to switch the meshed one-way clutch. As a result, the mechanism works just like a two-way clutch mechanism. We experimentally confirmed that the mechanism works as expected.
    Torque converter
    Drive shaft
    Gear train
    It is known that the shift processes of the four types of clutch-to-clutch shifts can theoretically be divided into two phases which are torque phase and inertia phase, but the execution orders are different. Two virtual clutch controllers are designed with the same eight states which include all control processes for these shifts. An equivalent method is proposed so that AT can be controlled just like DCT by adopting the torque ratios of oncoming clutch and offgoing clutch of each gear. The powertrain system model and the shift controller are established on Matlab/Simulink platform. The clutch-to-clutch shift processes have been studied based on the virtual clutch controller by software-in-the-loop simulations. Some typical problems in the clutch-to-clutch shift control are discussed and several control methods are compared to solve these problems.
    Powertrain
    Torque converter
    Citations (8)
    Wet clutches in an automatic transmission enable the transmission of the engine power by the frictional torque experienced and noted between disk and plates. Since the clutch frictional torque considerably affects the shift quality of an automatic transmission as well as the durability of the machinery, its friction characteristics must be carefully examined to meet the design requirements. The SAE No. 2 friction test machine is a well-known standard to evaluate mainly the friction characteristics of plate clutches along with the required automatic transmission fluids. This paper reviews the experimental analysis of the wet clutch friction characteristics by using the exclusively developed clutch test machine which is capable of controlling the clutch test procedure, in accordance with the applicable test standard and processing of the experimental data automatically. As the clutch test machine is designed for the accommodation of dual clutches which is applied to the real transmission, it can evaluate not only the clutch friction characteristics, but also an actuation performance of a measured clutch piston. In respect to friction characteristics involving dynamic friction coefficients, the energy absorbed in a clutch disk and the recorded temperatures of clutch plates during braking actions and procedures are also investigated. Additionally, the change of friction coefficients by the use of the repeated clutch application is also observed with the endurance test functions of an accurately calibrated and dedicated clutch test machine.
    Automatic transmission
    Torque converter
    Piston (optics)
    Friction torque
    Manual transmission
    Power transmission
    Friction loss
    Citations (0)
    Nowadays,the car industry development rapidly and the clutch is the mostly important device which determine the performance of the car.The thesis calculate the basic parameter of the clutch under the condition of giving the engine's output torque,rotate speed and the speed of the car.At the same time the analysis of various structural parts designed to improve the clutch and place the each part of the clutch reasonably and optimize the clutch of the car.
    Torque converter
    Citations (0)
    Abstract Determining the root causes of Noise, Vibration and Harshness (NVH) phenomena in modern automotive drivetrains is a task of critical importance. This research investigates the stability of dry clutch systems vibrational behaviour during engagement. A fully coupled dry clutch numerical model including the influence of friction is presented and validated using vehicle measurements. The clutch component frictional properties are measured using parts that exhibit aggressive NVH behaviour using representative tribometric experiments. The validated numerical tool highlights the occurrence of instabilities which are caused by modal couplings, particularly between the input shaft bending and clutch disc radial motions. Such a validated transient dynamics model of a dry clutch system has not hitherto been presented in the open literature.
    Transient (computer programming)
    Harshness
    Drive shaft
    Dry friction
    Drivetrain
    This study proposes a new design for a friction clutch actuator using the self-energizing principle for vehicle applications such that the power consumption for clutch control is significantly reduced. The self-energizing effect can be created by simply adding wedge structures to a conventional clutch system, and it assists in significantly reducing the actuation energy of the clutch with little additional cost. In this paper, a mathematical model of the clutch actuation system is derived on the basis of static force analyses with particular emphasis on the torque amplification factor due to the self-energizing effect. The slope angles of the wedges in the proposed clutch actuator are determined in order that the clutch system ensures appropriate torque amplification while considering various factors such as the variations in the friction coefficient and the return spring force. In addition, model-based analyses of the new clutch actuator system are performed in order to predict the dynamic effects of the self-energizing mechanism on the system, particularly for the clutch engagement process. The feasibility of the proposed clutch design and its high energy efficiency are verified experimentally using three prototypes with different slope angles.
    Torque converter
    Wedge (geometry)
    Citations (3)