Hydraulically-driven double-acting mud pump

A hydraulically-driven double-acting mud pump, comprising power motors, pressure oil pumps, a three-position four-way hydraulically-actuated directional valve, a hydraulic power end and a mud pump head, the power motors being connected to the pressure oil pumps in a transmission way, the pressure oil pumps being communicated with a port P of the three-position four-way hydraulically-actuated directional valve via a first pipeline, a port T of the three-position four-way hydraulically-actuated directional valve being communicated with an oil tank via a second pipeline, a port A and a port B of the three-position four-way hydraulically-actuated directional valve being both connected to the hydraulic power end, the hydraulic power end being connected to the mud pump head in a transmission way, a lower end of the mud pump head being communicated with a low-pressure manifold and two sides of the mud pump head being communicated with a high-pressure manifold;

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• further comprising control oil pumps and a two-position four-way hydraulically-actuated pilot valve, the control oil pumps being driven by control motors, the control oil pumps being communicated with a port P of the two-position four-way hydraulically-actuated pilot valve via a third pipeline, a port T of the two-position four-way hydraulically-actuated pilot valve being communicated with the oil tank via a fourth pipeline, a port A and a port B of the two-position four-way hydraulically-actuated pilot valve being communicated with one of two control ports of the three-position four-way hydraulically-actuated directional valve respectively via a fifth pipeline, and the two control ports of the two-position four-way hydraulically-actuated pilot valve being both connected to the hydraulic power end.