Technical improvement of proportional reducing valve used in hydraulic engineering vehicle
Technical improvement of proportional reducing valve used in hydraulic engineering vehicle
In many practical production occasions, such as rescue and disaster relief, slag cleaning, dangerous house demolition, cabin cleaning, garbage cleaning and other dangerous and harsh environments, it is necessary to remotely control the machinery. The vehicle wireless remote control driving technology, which integrates light, machinery, electricity and hydraulics, is an effective way to solve this problem.
1. Working principle of hydraulic system of slip steering engineering machine
The hydraulic system of the whole vehicle is composed of three interconnected hydraulic circuits, namely, working circuit, walking circuit and servo control mechanism circuit. Its schematic diagram is shown in Figure 15, and the whole hydraulic system is protected by safety valve.
(1) Working circuit. The hydraulic energy in the working circuit is provided by the large pump in the duplex pump 8. The oil is sucked from the oil tank 11 through the filter 14, and then transmitted to the distributor (two three position six way hydraulic directional valves) 3 at the rear of the machine through the pipeline, and the boom hydraulic cylinder 2 and bucket hydraulic cylinder 1 are controlled according to the driver's intention to meet the needs of normal work. At the same time, the safety valve in the working circuit limits the working pressure to a certain range, and the oil will flow back to the oil tank after heat dissipation through the radiator.
(2) Travel circuit. The travel circuit is realized through a hydrostatic transmission circuit, that is, two swashplate piston pumps 5 provide hydraulic energy, drive the quantitative motor 7 to rotate and output torque through the high-pressure pipeline, and transmit it to the wheels on both sides of the machine after passing through the reduction mechanism to realize the movement of the machine. The oil output by the motor flows directly back to the plunger pump to form a closed circuit. In order to solve the problems of lubrication and heat dissipation in the closed circuit, a makeup oil pump 6 is superimposed on each of the two plunger pumps. The pump flushes the plunger pump through the check valve 16 in the plunger pump box and directly enters the low-pressure branch of the closed circuit. The excess oil in the circuit flows back to the oil tank through the drain port of the motor and the plunger pump.
(3) Control circuit. The oil supplied by the small pump in the duplex gear pump is adjusted to the normal pressure range by the safety valve and then connected to the control device through the on-off valve. Turn on the servo handle 10 by manual operation, turn on the proportional reducing module 9 by remote operation, and activate the hydraulic brake 20 at the same time. Through the operation of the driver on the control device 9 or 10, the pressure oil is controlled to drive the distributor valve center to deviate from the middle position or the piston pump swashplate has an inclination output, so as to realize all control of the machine.
2. Electrohydraulic control transformation of slip steering engineering machine
The sliding steering engineering machine realizes the full hydraulic control of the whole vehicle by controlling the pressure reducing pilot valve. Therefore, the three-way electromagnetic proportional reducing valve module 9 is connected in parallel with the manual pressure reducing pilot valve module 10 by using the two position three-way electromagnetic directional valve 12, and the compatibility and exchange of manual remote control is realized by controlling the electromagnetic directional valve 12 (see Figure 15). This way can realize the hydraulic system transformation of slip steering engineering machine.
When the proportional reducing valve module 9 is used for remote operation, the working circuit and walking circuit of the engineering vehicle adopt the composite control mode, which can maximize the working efficiency of the engineering vehicle. Because the power of slip steering engineering machine is achieved by controlling and adjusting the engine throttle opening to change the engine speed. By adjusting the engine throttle opening, the hydraulic oil flow and pressure of the whole hydraulic system are changed to meet the requirements of different engine power under different working conditions, so as to realize the optimal control of the engine. Therefore, with the increase of engine throttle opening, the pump oil pressure of tandem pump 8 and swashplate piston pump 5 increases with the increase of engine speed, that is, the pressure of working circuit, travel circuit and control circuit of slip steering engineering machine increases with the increase of engine speed. Then, when changing the engine speed, changing the control current of the electromagnetic proportional reducing valve module 9 to change the oil pressure of the control circuit can effectively control the boom hydraulic cylinder 2, bucket hydraulic cylinder 1 and quantitative motor 7 in the working circuit to achieve the best operation effect, so as to meet the requirements of different engine power under different working conditions.
对于遥控手控兼容的工程车辆，要求手动控制应具有优先性。因此，二位三通电磁换向阀12不通电时，应是手动减压式先导阀模块10控制整车液压系统；通电时，三通电磁比例减压阀模块9控制整车的液压系统，此时，滑移转向工程机遥控作业。为了保证改装后的工程车辆能正常工作，需要在控制回路上利用梭阀实现手控和遥控系统的互锁。
这种改造方式的优点是不但满足了对手控原机型的液压系统最大继承性要求，而且使遥控电气系统最大程度地简易化，并且可以方便地并联到原液压回路中。而且，如果用三通电磁比例减压阀模块9替换原车上的手动减压式先导阀模块10，可实现对原车的纯遥控改造。
With the rapid development of digital wireless communication technology, there have been wireless remote control systems suitable for construction machinery with stable performance and reliable operation, such as the wireless remote control system produced by HBC company in Germany, the accelerator driver produced by sum Jack company in the United States, and the proportional reducing valve produced by TCN company in Italy, which have been widely used in the wireless remote control transformation of construction vehicles. Each element of the original manual operation of the engineering vehicle can accept the command of the remote control electrical signal and act accordingly, becoming a remote control vehicle.
