河北废钢剪切机厂

The problem and analysis of the shearing machine

该系统在实际使用过程中振动较大。振动导致系统元件的可靠性及寿命下降，连接螺栓的松动，管道开裂，使整个系统无法正常工作，而液压冲击是造成该系统振动的主要原因之一。究其原因，是系统采用节流阀背压缓冲不当而造成。

The system vibrates in the process of actual use. Vibration causes the reliability and life of the system components to decrease, the loosening of the connecting bolts and the cracking of the pipes make the whole system unable to work properly, and the hydraulic impact is one of the main reasons for the vibration of the system. The reason is that the system adopts the improper backpressure of the throttle valve.

节流阀的节流孔虽然是可调的，但在缓冲过程中却保持不变。有f力作用时，活塞速度不可能降低至零，只能趋于一个恒定值，因而机械冲击总是存在，说明用节流阀作背压缓冲元件，不能彻底消除冲击，从而引起系统振动。

The throttle orifice of the throttle valve is adjustable, but it remains unchanged during the buffer process. When the f force is used, the piston speed can not be reduced to zero and can only tend to a constant value, so the mechanical impact always exists, indicating that the throttle valve is a backpressure buffer element that can not eliminate the impact thoroughly, thus causing the vibration of the system.

液压缸有杆腔与无杆腔面积之比是S1：S2=1：2.82，在不计任何损失的情况下，剪切过程中p2S2=N+p1S1，N为负荷剪切力。当铸坯被突然剪断时，N=0，则p2S2=p1S1，得p1=2.82p2，其值远大于节流阀的合理压差0.2~0.3MPa。由于节流阀前后压力差大，能量损失也随之增大。损失的能量全部转换成了热量，被油液吸收后，致使油液通过节流口时温度升高，加剧油液变质、氧化，析出各种杂质，产生堵塞，引起节流阀堵塞现象的出现，使系统产生振动。

In a hydraulic cylinder, the ratio of the rod cavity to the rod free cavity is S1:S2=1:2.82. In the case of no loss, p2S2=N+p1S1 and N are the load shear forces during the shear process. When the slab is suddenly cut off, N=0, p2S2=p1S1, gets p1=2.82p2, which is much larger than the reasonable differential pressure 0.2~0.3MPa of the throttle valve. Due to the large pressure difference before and after throttle valve, the energy loss also increases. The energy of the loss is converted into heat, and the oil is absorbed by the oil, causing the oil to rise through the throttle, aggravating the oil metamorphism, oxidation, precipitating a variety of impurities, causing blockage, causing the phenomenon of throttle valve plugging and making the system vibrate.

剪切机液压系统采用节流阀作背压缓冲不当。而如果简单把节流阀去掉势必导致液压冲击和振动的加剧。

The hydraulic system of the shearing machine adopts the throttle valve as a backpressure buffer. If the throttle valve is removed simply, it will lead to the increase of hydraulic impact and vibration.