Fluid transmission includes gas (pressure) transmission and liquid transmission. Liquid transmission is divided into hydraulic transmission, hydraulic transmission and hydro viscous transmission. Based on PACHA's law, hydraulic transmission transmits power with the pressure energy of liquid; Hydraulic transmission is based on Euler equation and transfers power with short change of liquid momentum; Based on Newton's law of internal friction, hydro viscous transmission transmits power with the viscosity of liquid.
The basic components of hydraulic transmission are hydraulic coupling and hydraulic torque converter. The basic components of the hydraulic coupling are the pump wheel and turbine with several radial plane blades and constituting the working cavity. The hydraulic transmission oil circulates at high speed in the working chamber to transmit power. While the oil moves with the slave pump wheel, it makes centrifugal movement due to the action of centrifugal force. It absorbs mechanical energy from the pump wheel (and input shaft) and converts it into the increment of moment of momentum (MVR). The high-speed liquid flows from the pump wheel into the turbine for centripetal flow, releases the moment of momentum, drives the turbine (and output shaft) to rotate and drives the working machine (and load) to do work. The basic components of hydraulic torque converter are pump wheel, turbine and guide wheel. They are working wheels with spatial (curved) blades, which are arranged in relevant order to form the working chamber. The hydraulic transmission oil is stirred by the pump wheel turbine in the working chamber to make the liquid flow obtain the increment of momentum moment. After the guide wheel turns the direction of liquid flow, it rushes into the turbine to release the momentum moment (kinetic energy) and drive the turbine to drive the working machine to rotate and do work.
China's hydraulic components have developed rapidly in recent years. In 2003, the national annual output of hydraulic couplings was about 70000 units. It is widely used in the transmission of belt conveyor, scraper conveyor, ball mill, fan, compressor, water pump, oil pump and other equipment to improve the transmission quality and save energy. At present, the maximum output speed of hydraulic coupling in China is 6500r / min, the minimum power is 0.3kw and the maximum power is 7100kw. The development trend of hydraulic coupling is high speed and high power.
In the world, Voith company of Germany is the most famous product of hydraulic coupling. According to the data, there are 名媛直播 with rotating speed of 20000 R / min and power of 55000 kW, which shows that there is still a considerable gap between China and it. Of course, high-power hydraulic components have higher requirements for hydraulic transmission oil.
Hydraulic torque converter is mainly used in engineering machinery, petroleum machinery and diesel locomotive. Hydraulic torque converter is mainly matched with internal combustion engine, and its speed range is 2000 ~ 3000r / min. Construction machinery is widely used, with a maximum power of about 700hp and an annual output of about 70000 sets. Petroleum machinery is less used, with a power of 1500hp. Diesel locomotives have fewer applications, and the power is up to 3000HP.
Hydro viscous transmission is a new subject of liquid transmission, which is still in its infancy in China. Although hydro viscous transmission 名媛直播 (such as hydro viscous speed regulating clutch) are essentially different from hydraulic transmission 名媛直播 (such as speed regulating hydraulic coupling), they are regarded as the same type in several technical activities (such as development planning, standards, technical management, ordering activities, etc.) because of their similar performance and the same purpose (speed regulating and energy saving).
