The important effect of self feeding concrete mixer in the construction process is increasingly shown. Large scale self feeding mixer generally loads the mixed concrete from the mixing station and transports it to the construction site for use; The self feeding concrete mixer is usually near the construction site, which has the functions of self loading and unloading, batching and self mixing, reducing long-distance transportation and saving labor. The hydraulic system of self feeding mixer is divided into closed hydraulic system and open hydraulic system.

一客户的批量自进料混凝土搅拌车在运用进程中呈现以下几种毛病现象：（1）空载下，转罐转速可到达规划要求，而装满料今后很难起动，即便在发起机大转速下转罐转速也很低；（2）液压油散马达的进油胶管呈现多台爆管毛病；（3）转罐马达的毛病率十分高，多台呈现马达内部卡死或轴端密封损坏向外串油。

A customer's batch self feeding concrete mixer has the following defects in the process of operation: (1) under no-load condition, the rotating speed of the drum can reach the planning requirements, but it is difficult to start when it is full in the future, even under the high speed of the initiator, the rotating speed of the drum is very low（ 2) The oil inlet hose of hydraulic oil dispersion motor has the problem of multiple tube explosion（ 3) The failure rate of the rotary drum motor is very high, many motors are stuck inside or the shaft end seal is damaged, and oil flows out.

从原理上来看，自进料混凝土搅拌车液压体系为开式负载灵敏开芯回路，通过设备在发起机上的齿轮泵持续向换向阀供油，由先导操控阀作为总开关，通过操控电磁换向阀的翘板开关完结转罐马达的正转与回转。换向阀的回油分两路回油箱：一路通过节流阀回油箱，另一路驱动油散马达，为其他体系的回油进行散热。

In principle, the hydraulic system of the self feeding concrete mixer is an open load sensitive open core circuit, which continuously supplies oil to the change-over valve through the gear pump on the initiator. The pilot control valve is used as the main switch, and the forward rotation and rotation of the rotary tank Marta are completed by controlling the rocker switch of the electromagnetic change-over valve. The return oil of the reversing valve is divided into two ways: one is returned to the oil tank through the throttle valve, and the other is driven by the oil dispersion motor to dissipate heat for the return oil of other systems.

通过毛病状况与原理比照剖析，以为换向阀的回油通过节流阀的阀口来操控 油散马达的作业转速，且节流阀阀口是在出厂前依据发起机怠速调节油散马达转速的，一旦节流阀阀口固定，通油才能就会被约束在必定的范围内。

Through the analysis of the fault condition and the principle, it is thought that the return oil of the reversing valve controls the working speed of the oil dispersion motor through the orifice of the throttle valve, and the throttle valve orifice regulates the speed of the oil dispersion motor according to the idle speed of the initiator before leaving the factory. Once the orifice of the throttle valve is fixed, the oil can be restricted in a certain range.

但是换向阀的输出流量与发起机的转速成正比联系，在发起机高速作业时，换向阀T口油液无法快速回到油箱，形成油散马达的进油管处压力过高，超越胶管接受的压力，所以爆管现象时有发作。因无法得到更具体的技术参数与材料，重载转速慢及马达毛病率高是否有直接相关，通过现场检查实车的体系现状及运用进程工况，从运用工况来剖析毛病原因。

However, the output flow of the directional valve is directly proportional to the speed of the initiator. When the initiator works at high speed, the oil at port t of the directional valve can not quickly return to the oil tank, resulting in the high pressure at the oil inlet pipe of the oil dispersion motor, which exceeds the pressure accepted by the rubber hose, so the tube burst occurs from time to time. Because we can not get more specific technical parameters and materials, whether there is a direct correlation between the slow speed of heavy load and the high fault rate of motor, through the on-site inspection of the system status and operation process of the real vehicle, we analyze the fault causes from the operation condition.