High water-based hydraulic motors can be used in fields such as coal mining, food, and underwater operation due to their medium-friendly nature. However, currently high water-based motors still use hydraulic oil motor structure, only replacing the medium with high-water-based emulsion. Traditional shaft and disk flow structures will suffer severe leakage and rusting phenomena under low-speed, high-pressure, and high water-based conditions. Additionally, the current valve flow structure problem is that one plunger needs to be equipped with two check valves, which causes the motor to have a larger volume, and the flow valves must be accurately matched. Otherwise, there will be channeling and fluid entrapment phenomena. In view of the above problems, a shuttle valve flow structure was proposed to control the motor flow distribution, which consists of a shuttle valve and a cam. The cam drives the plunger’s liquid intaking and discharging process. Firstly, the flow valve was structurally designed and theoretically analyzed, revealing its flow distribution principle. Secondly, the dynamic response characteristics of its parameters were analyzed in AMESim. The cam driven by the sine acceleration function curve was selected to control the valve core, and the flow-through hole with a diameter of 0.6 mm, with small pressure and flow fluctuations, was used. Additionally, the motor’s torque fluctuation was 7.39%, verifying the shuttle valve’s good flow distribution performance. Fluent simulation was used to optimize the valve’s internal flow field and select the notch structure with small pressure drop and uniform velocity distribution. Based on this, prototype preparation and experimental analysis were carried out. Under 16 MPa working condition, the plunger chamber can quickly build pressure, the pressure fluctuation at the inlet of the flow valve is 12.5%, and the leakage is 2 drops/min. It can be seen that after the shuttle valve is applied to the high water-based hydraulic motor, stable flow distribution can be achieved.

In applications such as coal mining, food and underwater operations, low speed high torque high water-based hydraulic motors have the advantages of high power-to-weight ratio and medium compatibility. However, the current high-water-based hydraulic motors still maintain the same flow distribution structure as oil motors and only replace the working medium with high-water-based emulsion instead of hydraulic oil. Traditional flow distribution disc structures use spring force to ensure sealing. Under low speed, high pressure, and high water-based conditions, the flow distribution disc wears heavily, resulting in serious leaks. For high-water-based emulsion drive systems, this paper proposed a valve flow distribution mechanism comprising valves, bearings, and a pentagon-wheel. The motor’s intaking and discharging process is controlled by a check valve, and the opening and closing of the valve is controlled by the pentagon-wheel. Then the paper carried out comparative analysis on flow distribution rules, advantages and disadvantages of eccentric-wheel, cam, and pentagon-wheel flow distribution mechanisms. It is found that the pentagon-wheel flow distribution structure can reduce the concentration of push rod stress and solve the phenomenon of push rod self-rotation jamming. Finally, the superiority of the five-star wheel flow distribution structure was verified by using AMESim. The prototype was prepared and the performance experiment was carried out. The results show that the pressure in the plunger cavity can be quickly established under different speed (10~90 r/min) and pressure (5~21 MPa). Compared with traditional disc flow distribution mechanisms, the leak rate of the valve flow distribution mechanism under high-water-based conditions of 21MPa and 90r/min is only 0.15 mL/min, significantly improving motor volume efficiency.