Composition and function of hydraulic torque converter

The car parts and the car as a whole are complementary and harmonious, and teamwork is also important. Hydraulic torque converter is an important part of automobile power transmission. It has been widely used because of its advantages such as continuously variable transmission, extending the service life of transmission system, etc. The hydraulic torque converter can not only transmit torque, but also automatically change the torque value output by the turbine with different turbine speeds when the pump wheel torque is unchanged.

Composition of hydraulic torque converter - definition

Hydraulic torque converter is a kind of non rigid torque converter with liquid as working medium, which is one of the forms of hydraulic transmission. The picture shows the hydraulic torque converter, which has a closed working chamber in which liquid circulates. The pump wheel, turbine and guide wheel are connected to the input shaft, output shaft and housing respectively. When the power machine (internal combustion engine, motor, etc.) drives the input shaft to rotate, the liquid flows out of the centrifugal pump wheel, passes through the turbine and guide wheel in turn, and then returns to the pump wheel, circulating again and again. The pump wheel transfers the mechanical energy of the input shaft to the liquid. The high-speed liquid drives the turbine to rotate, transferring energy to the output shaft.

Composition of hydraulic torque converter - working principle

The three working wheels of the hydraulic torque converter are installed in the closed torque converter housing, which is filled with transmission fluid (ATF). The pump wheel is driven by the engine. The turbine is fixed on the turbine shaft, which is connected with the transmission input shaft. The guide wheel is fixed on the transmission housing through the guide wheel shaft and suspended between the pump wheel and the turbine. A certain clearance is also left between the guide wheel and the pump wheel and the blade end face of the turbine. There is no mechanical connection between the three working wheels. In order to ensure the performance of the torque converter and the good circulation of ATF, the blades of the pump wheel, turbine and guide wheel are bent into a certain radian and arranged in a radial inclined manner.

Like the hydraulic coupler, when the hydraulic torque converter works normally, the oil stored in the annular cavity circulates around the axis of the torque converter and also circulates in the circulation circle, so the torque can be transmitted from the pump wheel to the turbine. Different from the hydraulic coupler, the hydraulic torque converter can not only transmit torque, but also automatically change the torque value output by the turbine with different turbine speeds when the pump wheel torque is unchanged, that is, "torque conversion". The reason why the hydraulic torque converter can play the role of torque conversion is that it has an additional guide wheel mechanism than the coupler in structure. In the process of liquid circulation, the fixed guide wheel gives the turbine a reaction torque, which makes the torque output by the turbine different from that of the pump wheel.

Composition of hydraulic torque converter - do all automatic transmissions have hydraulic torque converter

Not necessarily, the hydraulic torque converter can be connected to the engine in a soft way so that it will not stop when the vehicle encounters heavy loads. However, the hydraulic torque converter also has its own weakness, that is, the loss of energy transmission is converted into heat energy. Therefore, German departments generally use double clutch for direct connection. Although Nissan's current Teana and other major vehicles are equipped with torque converters, they use clutches in the torque converter structure. When the efficiency of the torque converter reaches more than 75%, the clutch is combined. The transmission is directly connected with the engine to reduce efficiency loss. Prompt: The current automatic transmissions mainly include the following types: 1. AT pure automatic transmission, with hydraulic torque converter; 2. CVT stepless transmission, also with hydraulic torque converter; 3. DSG dual clutch transmission, which has no hydraulic torque converter.

The role of hydraulic torque converter can not be underestimated, it is very important for our cars. Since there is no clutch between the engine and the gearbox, the connection between them is realized by the hydraulic torque converter, which is used to transmit speed and torque, and to make the connection between the engine and the automatic transmission become non rigid so that the automatic transmission can shift automatically.