Boom cylinder is an important part of the excavator working device, used to complete the lifting of the boom. In order to improve the working efficiency and make the boom rise rapidly during the work, the oil flow rate of the boom cylinder is required to be large. However, when the descent increases the dead weight of the working device, it may cause danger due to the boom falling too fast, such as smashing the working device or bucket crashing the transport vehicle, etc., so the boom cavity cylinder is installed on the large cavity circuit There is an adjustable one-way throttle valve. This kind of one-way throttle valve can not only prevent the fuel inlet of the large cavity of the boom cylinder from being obstructed, but also control the oil return speed of the large cavity by adjusting the opening of the valve according to the descending speed of the boom.
WY32 and WY20 hydraulic excavators are equipped with two boom cylinders and two adjustable one-way throttle valves. The principle is shown in Figure 1-13. When adjusting the one-way throttle valve, it is necessary to meet the requirements of the lowering speed of the boom, and the opening of the two one-way throttle valves should be exhausted, and the amount is close, otherwise the oil return through the two throttle valves will be different. . The oil flow with a large opening is large, and turbulence may occur in the subsequent pipeline, which increases the pressure loss. After this pressure loss becomes heat, the temperature rise of the system can be accelerated.
But in actual use, the adjustment of the two one-way throttle valves is a very troublesome thing. For this reason, through theoretical analysis and use investigation, it was decided to use the two one-way throttle valves in the large cavity oil circuit of the two-arm cylinder Change to a large-diameter one-way throttle valve (see Figure 1-14), modify the boom distributor accordingly, and then install it on the WY32 excavator.
The improved one-way throttle valve is much more convenient to adjust, as long as the boom lowering speed requirements are met during the adjustment, the flow in the following two pipelines can be basically guaranteed to be consistent. That is to say, after the improvement, the pressure loss in the two pipelines is less than the original, and the heat generated is smaller.
Single one-way throttle valve and improved boom distributor are installed on the WY32 excavator on the construction site, and the installation, adjustment and maintenance are more convenient than the original. In use, the pressure of the two boom cylinders is equal, the load is uniform, and the work is synchronized. It can meet the working requirements of the host, and the cost of each host can be reduced, which has certain economic benefits.
