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What is torque converter?

A non-rigid torque converter that uses liquid as the working medium is one of the types of hydraulic transmission. The image shows the hydraulic torque converter. It has a closed working chamber, and the liquid flows circularly in the chamber. The pump wheel, turbine wheel and guide wheel are respectively connected to the input shaft, output shaft and casing. When the power machine (internal combustion engine, electric motor, etc.) drives the input shaft to rotate, the liquid flows out of the centrifugal pump wheel, passes through the turbine wheel, guide wheel and then it returns to the pump wheel, and then flows in circles. The pump wheel transfers the mechanical energy from the input shaft to the liquid.

The high velocity fluid drives the turbine to rotate and transfer power to the output shaft. The torque converter transmits torque by generating a change in momentum from the interaction of the fluid and the blades. The main feature of the torque converter as opposed to the hydraulic coupler is that it has a fixed idler. The guiding effect of the idler on the liquid causes the output torque of the torque converter to be greater or less than the input torque, so it is called a torque converter.

The ratio of the output torque to the input torque is called the torque conversion coefficient, and the zero speed torque conversion coefficient when the output speed is zero is usually about 2-6. The torque conversion coefficient decreases with increasing output speed. The input shaft and output shaft of the torque converter are based on a liquid connection and there is no rigid connection between the working components.

The characteristics of the hydraulic torque converter are: it can eliminate shock and vibration, and has good overload protection and starting performance; the speed of the output shaft can be higher or lower than the speed of the input shaft, and the speed difference between two shafts varies with the size of the transmitted torque; yes Good performance of automatic transmission, the output speed will decrease automatically when the load increases, and vice versa; It will ensure that the driving machine has a stable working area and the transient changes of the load will basically not be reflected on the power machine.

The hydraulic torque converter has a higher efficiency near nominal operating conditions, with a maximum efficiency of 85-92%. The impeller is the core of the torque converter. Their type and location, as well as the shape of the blades, have a decisive effect on the performance of the torque converter. Some torque converters have more than two turbines, idler wheels, or pump wheels for different performance.

The most common are forward rotation (output shaft and input shaft rotate in the same direction), single-stage torque converter (only one turbine). The performance characteristics of both the torque converter and the coupler are called integral hydraulic torque converters. For example, the guide wheel can be fixed and can also rotate with the pump wheel. For the torque converter to work normally, prevent cavitation and ensure heat dissipation, an auxiliary oil supply system and a cooling system with a certain oil supply pressure are required.

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