The invention discloses a tension and
compression testing machine hydraulic loading
system adopting differential control of proportional overflow valves. The
system comprises a
hydraulic pump station, a low-pressure filter, an oil return one-way valve, the high-pressure proportional overflow valve, a flow dividing valve, the two low-pressure proportional overflow valves, an oil inlet one-way valve, two electromagnetic reversing valves, two tension and compression force sensors, two hydraulic cylinders, two displacement sensors and a force and displacement compound controller. The differential control of the proportional overflow valves and compound control over the pressure and displacement of the hydraulic cylinders by pressure valves are adopted, and the micro force control and loading force control precision of a testing
machine is improved; and during static and quasi-
static loading of the tension and compression force testing
machine, the loading force and the
hydraulic cylinder synchronous displacement in the loading process are controlled in real time, and control over any loading curve and
synchronous control over the multiple hydraulic cylinders are achieved. By means of the tension and
compression testing machine hydraulic loading
system adopting differential control of the proportional overflow valves, the tension and
compression testing machine can adapt to various complicated loading work conditions. The tension and compression testing machine hydraulic loading system adopting differential control of the proportional overflow valves is suitable for the occasion where the loading force changing range is wide, the adjusting precision is high, and the hydraulic cylinders frequently need to perform
synchronous control during static and quasi-
static loading.