A flow distribution pair for a torque-balanced water hydraulic axial piston pump

Abstract

A torque-balanced flow distribution pair for water hydraulic axial piston pumps mainly comprises a floating liner plate, a floating bushing, a flow distribution disk, three eddy current micro-displacement sensors, an amplifying and conditioning circuit, a control unit and a power amplifier, wherein the floating bushing is mounted on one end of a floating disk, a ring-shaped electromagnet is mounted on the other end of the floating disk, and a circular electromagnet is correspondingly mounted in the low-pressure flow distribution area of the flow distribution disk. The hydraulic backward thrust of the low-pressure flow distribution area of the torque-balanced flow distribution pair can be automatically compensated, so that the stress between the two end surfaces of the flow distribution pair is more uniform, consequently, the unbalanced loading torque of the high-pressure flow distribution area is balanced, the abrasion of the low-pressure flow distribution area and the leakage flow of the high-pressure flow distribution area are reduced, not only can the volumetric efficiency and service life of a water hydraulic axial piston pump be increased and prolonged, but also the torque-balanced flow distribution pair is highly universal and is highly convenient to dismount, mount, replace and maintain, and the torque-balanced flow distribution pair is applicable to swashplate or angle type valve plate flow distribution hydraulic axial piston pumps with pure water as working medium.

Description

technical field [0001] The invention belongs to the technical field of water hydraulic transmission, and relates to a swash plate or inclined shaft hydraulic axial plunger pump with pure water as the working medium, in particular to a flow distribution pair for a torque balanced water hydraulic axial plunger pump . Background technique [0002] The water hydraulic transmission technology using pure water (including fresh water and sea water) as the working medium has many advantages such as no pollution, good flame retardancy, and wide source of medium, and has unique advantages in many fields such as food processing, seawater desalination, and marine resource development. . As the power component, the water hydraulic axial piston pump is the "heart" of the entire water hydraulic transmission system. Its performance has a decisive impact on the entire system, and the flow distribution pair is the most critical friction in the water hydraulic axial piston pump. One of the v...

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Problems solved by technology

[0003] Compared with the traditional hydraulic axial piston pump, the distribution pair of the water hydraulic axial piston pump is more prone to wear and failure, because pure water (including fresh water and sea water) not only has low viscosity but also poor lubricity. The leakage flow rate of pure water (including fresh water and sea water) is nearly 30 times greater than that of hydraulic oil when passing through the same friction pair gap, resulting in a significant decrease in volumetric efficiency; moreover, it is difficult for pure water to form a lubricating film The thickness of the lubricating water film is only 1 / 3 to 1 / 20 of that of the oil film. In addition, it is difficult to maintain a balance between the hydraulic reverse thrust and the pressing force between the two ends of the distribution pair. Usually, the hydraulic reverse thrust around the high-pressure distribution window is farther away. It is much higher than the hydraulic reverse thrust around the low-pressure flow distribution window. The imbalance of the hydraulic reverse thrust produces an unbalanced load moment. As a result, a large leakage flow is generated due to the large distribution gap on the side of the high-pressure distribution window, which reduces the volumetric efficiency of the pump; on the side of the low-pressure distribution window, due to the small distribution gap, the lubricating water film produced is very thin and difficult to form The water film support with effective stiffness can easily cause direct contact between the moving surfaces of the distribution pair, resulting in dry friction and aggravated wear, which affects the service life of the pump

[0004] Since the hydraulic axial piston pump is affected by many factors, its pressure field, velocity field and temperature field are also very complicated. However, most of them focus on the research on the working conditions and friction and lubrication laws of the existing oil pressure distribution pairs, and the existence of eccentric load moments caused by the uneven pressure distribution of the distribution pairs, especially those used in water hydraulic axial piston pumps. , so that the eccentric wear reduces the volumetric efficiency and life of the water hydraulic axial piston pump, and there are few studies on it, let alone a better solution.

Patent 200510096287.3 discloses an oil film thickness control system for an axial piston pump with flow distribution on the end face, which compensates the hydraulic reverse thrust between the two end faces of the flow distribution pair through a closed-loop controllable electromagnetic force, which can effectively avoid the oil pressure of the axial piston pump. The fault of the distribution plate burning occurs, but it is not effective for the eccentric load moment between the two end faces of the distribution pair of the balanced water hydraulic axial piston pump. The reason is that it increases the hydraulic reaction between the two end faces of the distribution pair as a whole. Thrust instead of targeted compensation for hydraulic reverse thrust around the low-pressure distribution window, which will lead to an overall increase in the fit gap between the two end faces of the distribution pair, but the wedge-shaped space still exists, because it is much thinner than the oil film and water film. The direct contact of the moving surface of the distribution pair increases the leakage flow rate, which affects the volumetric efficiency of the whole machine; in addition, due to the large mass of the cylinder itself, under the high-pressure and high-speed rotation conditions of the plunger pump, a large Due to the inertial force, the electromagnet installed on the cylinder needs high power and high response current to be driven, which makes it difficult to accurately and timely compensate the hydraulic reverse thrust between the two end faces of the distribution pair; moreover, the pressure sensor is used first Indirectly measure the pressure between the two end faces of the flow distribution pair, and then calculate the gap change between the two end faces of the flow distribution pair through the control program and judge the method of wedge-shaped space or eccentric wear, which is affected by the complex working conditions and pressure field distribution of the axial piston pump, etc. Influence, the requirements for the control program are extremely high, and it is very difficult to realize

The more important issue is that since the thickness of the water film is much thinner than that of the oil film, most pressure sensors including piezoelectric crystal pressure sensors are contact sensors. Measure the pressure between the two end faces of the flow distribution pair, because the two end faces of the flow distribution pair are continuously subjected to alternating loads, which drives the cylinder to produce a constantly changing axial displacement, and the flow control plate and the pressure sensor installed on it are stationary However, the cylinder rotates at a high speed, which will cause the surface of the contact sensor to be constantly rubbed, and it is easy to wear and fail in a short period of time, which will become a short board that affects the service life of the whole machine.

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