Created on:2021-04-23 09:29

Hydraulic pump and hydraulic motor

Hydraulic pump and hydraulic motor

At present, with the rapid development of hydraulic pump and hydraulic motor series abroad, water can be supplied.

Because gear pump is not suitable for low viscosity medium, screw pump in pure water hydraulic only has very small applications, such as low pressure and need to add lubricant, so pure water hydraulic pump is mainly plunger pump, three piston reciprocating pump and a small number of vane pump. According to different lubrication forms, piston pump and three piston reciprocating pump can be divided into two types: oil lubricated chamber and non oil lubricated chamber.

In the hydraulic pump / motor with oil lubricated chamber, the contact surface of oil lubricated bearing and plunger pair is isolated from the pressure water. These components include radial piston pump, valve port axial piston pump and three piston reciprocating pump. Their reliability mainly depends on the effect of isolating the two kinds of fluid, otherwise their collusion will damage the driving mechanism or pollute the lubricating medium. In this kind of components, the three piston reciprocating pump is the most typical, with the largest production quantity and specifications. It has excellent cost performance, but it has large volume, small power density and large pulsation. The output pressure range of the three piston reciprocating pump is 5 ~ 100MPa, and the output flow is from several liters per minute to thousands of liters or more.

Water pump / motor without oil lubrication chamber uses water itself as lubricant. This is also the route adopted by most manufacturers of pure water hydraulic components. In the past decade, the latest development in the field of water pressure is the emergence of pure water hydraulic radial and axial piston pumps. Engineering ceramics, reinforced plastics and high-strength corrosion-resistant alloy are widely used in friction parts of pumps. For example, the seawater hydraulic pump developed by Japan's Xuanchang Industrial Company uses Si3N4 to make bearing balls and 440C stainless steel to make bearing rings. The metal in the pump is cobalt alloy, and the plunger pair, slipper pair and swash plate pair are made of ceramics and heat-resistant resin. The working pressure of the pump is 20.6mpa, the displacement is 7.05ml/r, the rotational speed is 1800r / min, and the volumetric efficiency is more than 90%. In addition, the axial piston pump and axial piston motor produced by Danfoss company in Denmark also use water as lubricant. The pressure is between 14-21mpa and the flow rate is within 100L / min.

At present, vane pump is mainly high-speed small torque pump, while vane motor is mainly low-speed large torque motor.

At present, there are few commercial products for users to choose from, so their application is limited.

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