Browse Topic: Dry disc clutches
Wysong USA has been manufacturing industrial press brakes, hydraulic shears, and mechanical shears for sheet metal and plastics for nearly 120 years. Like many companies, their motto was “if it ain’t broke, don’t fix it,” so their product had remained essentially the same. But during a customer visit that motto clashed with another company saying, “the customer is always right.” This customer had replaced the dry clutch brake for an oil shear clutch brake that was more accurate. “The customer is always right” won, so Wysong updated their product line and increased accuracy while reducing costs, making it a win all around.
Dual Clutch Automatic Transmission (DCT) has the characteristics of light weight, fast shift speed and high transmission efficiency. Electric vehicles equipped with dual clutch transmission can effectively improve vehicle power performance and economy. Electro-hydraulic control system, as a key component of transmission, determines the quality of shift. In this paper, an electro - hydraulic control system is designed based on two - speed dry dual clutch transmission of electric vehicle. Firstly, the hydraulic components of the system were selected and calculated based on the vehicle parameters. Secondly, the electro-hydraulic control system of the dual clutch transmission was established according to the transmission control strategy and the matching hydraulic valve body assembly was designed. Then, the key components of the system were simulated to analyze their dynamic shift characteristics and response characteristics. Finally, through various tests, it is verified that the designed electro-hydraulic control system and transmission meet the design requirements. The results show that the electro-hydraulic control system can meet its working characteristics and shift requirements.
Agricultural Tractors consisting of a conventional manual transmission and dry friction clutch are mostly assembled with a mechanical type of clutch release mechanism where a defined amount of free play needs to be maintained between the clutch and Release Mechanism. A defined free play is required for efficient operation of clutch, Release Bearing as well as to ensure the durability of the system. As the clutch disc wears the free play between diaphragm spring or levers (as the case may be) and the release bearing is reduced. The rate at which the clutch disc wears is dependent on many factors like working condition of the tractor, grade of the friction lining material, experience of the driver, etc. This makes it very difficult to predict the exact timeline when the free play needs to be adjusted even though an approximate indication is given in instruction manuals. In today’s situation the adjustment of the free play is carried out manually and approximately. Many times, the adjustment activity is neglected, and this leads to early failures of the clutch release bearings and / or clutch. The purpose of this solution is to ensure that the free play adjustment is automatically carried out ensuring longer life of components. The system used for automation consists of a sensorized bearing, smart logic controller, and an actuator motor. As the adjustment would be carried out digitally, it would check and ensure the required free play is always available in the system, as well as eliminate manual intervention. The same can be extended to other areas of applications like commercial vehicles etc. where a mechanical release system is used. This paper describes the innovative ways to automatically maintain a fixed value of free play between the Diaphragm Spring fingers and the clutch release bearing at any point of time as well as to automate this process without manual intervention.
Coil springs are crucial components of the clutch damper. Quantifying the stresses accumulated on them during operation is crucial in the prediction of remaining usable spring life. This paper demonstrates the use of a mathematical model-based approach in predicting the behavior of localized stresses on the spring used in clutch dampers. An equivalent cantilever beam model for spring coils solved using the theory of elastic stability is utilized to predict the spring response in operation, a contact model that translates the spring response into localized stresses due to wear and iterative wear model that accounts for surface morphology and change in geometry due to wear is illustrated in this paper for the prediction of wear.
This paper develops a lumped-parameter multi-plates wet clutch Offset Compound Gear (OCG) transmission dynamics and its thermal model for dual-speed rotorcraft applications with an active clutch slip-speed control. This model includes the Reynolds equation for the clutch oil film thickness, the clutch thermal model, the clutch transferred torques (viscous and asperity torque) and the clutch disengagement model. The wet clutch/OCG transmission system is implemented in Matlab® Simulink™ to manage the upshift clutch temperature rise, which is a main issue need to handle for a dual-speed helicopter transmission. Here, the clutch temperature rise is treated by injecting a certain amount of coolant during engagement so that the temperature rise for the wet clutch is much lower than that of an dry clutch. In order to transfer a required torque using the available power, the sizing of the wet clutch could be evaluated via the developed wet clutch/OCG transmission model. This study shows that the temperature rise drops as the wet clutch oil flow rate increases adding extra weights compared with the dry clutch. The simulation also captures a phenomenon that a larger clutch engagement pressure might be required for the wet clutch to transfer the same torque since the wet clutch oil viscosity drops as the oil temperature increases during the clutch engagement.
Accuracy of heat flux models is critical to clutch design in case of excessive temperatures due to large amounts of friction heat generated in the narrow space. Pressure distribution on the clutch friction interface is an important factor affecting heat flux distribution, thus affecting temperature distribution. In this paper, an experiment is conducted to obtain the pressure distribution for one typical dry clutch equipped with a set of diaphragm spring. Considering that the frictional interface is in contact, this study makes use of pressure sensitive film and acquires data based on image processing techniques. Then a polynomial mathematical model with dimensionless parameters is developed to fit the pressure distribution on the friction disc. After that, the proposed pressure model is applied to a thermal model based on finite element method. In addition, two conventional thermal models (i.e., uniform heat flux model and uniform pressure model), are implemented for comparison. Finally, a dynamometer test is carried out to verify the proposed pressure model. The simulation results from the proposed pressure model and other two models are provided with temperature profiles along with time and radius. The results from the non-uniform pressure model agrees the experimental results better than those from the two conventional models. Therefore, the proposed non-uniform pressure model could provide a more accurate temperature prediction.
Vicura is a developer of manual transmissions and dry dual clutch transmissions, as well as powertrain integration in a large number of front wheel drive and all wheel drive applications. The company’s engineers are responsible for a broad range of complex simulation and analysis testing including system, structure, and fluid mechanics. The team performs critical simulation and analysis to ascertain the strength, stiffness, thermal, and dynamic behaviors of all possible transmission assemblies and components (housings, shafts, gears, synchronizers, clutches, etc.).
The objective of this glossary is to establish uniform definitions of parts and terminology for engine cooling systems.
The objective of this glossary is to establish uniform definitions of parts and terminology for engine cooling systems.
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