A dual oil pump hydraulic control system and control method for a fatigue testing machine

Abstract

A dual oil pump hydraulic control system and method for a fatigue testing machine comprises an oil cylinder, a piston, a first oil tank, a first oil pump, a first servo motor, a first servo motor driver, a second oil tank, a second oil pump, a second servo motor, a second servo motor driver and a data acquisition control system. The oil inlet of the first oil pump is connected with the first oil tank. The oil outlet of the first oil pump is connected with the oil cylinder. The first servo motor is connected with the first oil pump, and is connected with the first servo motor driver. The oil inlet of the second oil pump is connected with the oil cylinder. The oil outlet of the second oil pump is connected with the second oil tank. The second servo motor is connected with the second oil pump, and is connected with the second servo motor driver. The first servo motor driver and the second servo motor driver are connected to the data acquisition control system. Compared with prior art that one oil pump is adopted as a power source, the oil pump hydraulic control system and method have the advantages that the time needed for loading or unloading the fatigue testing machine is greatly shortened, and the loading and unloading frequency of the fatigue testing machine is greatly improved.

Description

【Technical field】 [0001] The invention relates to a double oil pump hydraulic control system and a control method of a fatigue testing machine. 【Background technique】 [0002] The fatigue testing machine is a machine mainly used to measure the fatigue performance and fatigue life of metals and their components at room temperature, and to complete fatigue tests such as prefabricated cracks and crack growth. [0003] Fatigue testing machines generally use hydraulic power sources. In the past, fatigue testing machines mainly used ordinary motors to drive ordinary quantitative pumps to deliver oil to the working cylinders, and adjusted the power devices through regulating valves (flow valves) or overflow valves (pressure valves). Output pressure and action speed have the advantage of easy maintenance, but the disadvantage is that the oil pump always outputs oil at a large flow rate, which causes the temperature of the hydraulic oil to rise too high, so that the hydraulic system ...

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Problems solved by technology

[0014] Since the motor in this system runs at the rated speed and n×q is a constant, the power consumption of the motor is only related to the system pressure. When running at low speed or maintaining pressure, most of the work consumed by the motor is idle work, most of which are converted into heat energy and flow back to the oil tank through the pressure oil through the proportional relief valve, causing the system to heat up. In many cases, especially in High-pressure and highly variable working conditions such as fatigue testing machines require the installation of cooling systems, resulting in low energy utilization during operation and increased costs

[0015] The existing technology often uses an oil pump as the power source, and the working diagram of a single oil pump is as follows figure 1 As shown, when loading, the oil pump is turning to the oil cylinder to feed oil. When unloading, it needs to stop from the forward rotation and then start to reverse, and the oil cylinder returns oil. It takes longer to complete a loading and unloading

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