What is the friction pair of a hydraulic pump? What are the requirements for friction pairs?

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The friction pair of a hydraulic pump may be a new term for many people, but for hydraulic pumps, the friction pair is also an issue that deserves our attention. http://img.mp.itc.cn/upload/20170112/ca1ff89bde444775ba47113c5fb0f912_th.jpg As we know, the three main components of a positive-displacement hydraulic pump are the stator, the rotor, and the plunger. When the hydraulic pump is in operation, in one case the plunger moves within the stator, with the rotor carrying out relative motion with respect to both the plunger and the stator; in another case, the plunger moves within the rotor, and together the plunger and the rotor move relatively with respect to the stator. As a result, a pair of friction pairs is formed between any two parts that are in relative motion. This is reflected in the fact that various hydraulic pumps have different friction pairs. In gear pumps, it is between the teeth, between the tooth tips and the housing, as well as between the gears and the side plates; in vane pumps, it is between the vanes and the rotor, between the rotor and the distribution plate, and between the vanes and the stator ； In piston pumps, the piston and the cylinder bore, the cylinder and the distribution plate, as well as the slip sleeve and the swash plate; in screw pumps, the threads and each other, the screw and the housing, etc., can all be considered various types of friction pairs. Since the key components that make up these friction pairs are generally subjected to friction conditions characterized by high relative speeds and high contact pressures, their performance in terms of friction and wear has a direct impact on the volumetric efficiency, mechanical efficiency, operating pressure of the hydraulic pump, as well as its service life. Therefore, we have the following common requirements for these friction pairs: 1. They must possess good sealing properties to ensure no leakage or only minimal leakage, thereby improving the volumetric efficiency of the hydraulic pump. 2. It serves as a support, transmitting forces of a certain magnitude. 3. It performs reliably during operation, experiences minimal wear, has good wear resistance, and a long service life. 4. Low heat generation, low noise, no cavitation, and impact resistance. The above requirements thus dictate the high precision demands in various aspects such as the material of the parts that form the friction pair and its design. In high-precision hydraulic systems, these components are required to meet the highest standards of precision. Learn more: Rexroth gear pumps