彩涂板生产防止液压系统故障的方法

a速度控制失效

彩涂板生产速度控制失效可以说是由爬行、速度慢、速度不稳定和速度不可调等因素造成的。(1)爬行。压缸在低情况下产生时斯时续的动现象叫爬行。彩涂板生产行现象有许多因素引起的，例如:系统中混入了空气，空气的具有可压缩性使液压油也具有可压缩性，导致油液的刚度降低，引起如油缸等的执行件产生爬行现象。另外，爬行现象还可以由其他原因引起，例如:压力调得过低;系统内压力和流量有过大的波动;执行件磨损重引起的泄漏;电路失常等几种原因都会使执行元件运动不均，最终导致系统速度产生爬行现象。

(2)他现象。1)速度慢。液压泵、换向阀和其他执行件磨损;溢流阀调节压力过低;截流阀或调速阀未能充分打开;系统的负载过大等都会引起系统的速度降低。2)速度不能调节。流量控制阀卡死;手动调速阀损坏都很自然地引起速度不可调节的现象。另外，电液比例调速阀如果电信号本身不能调节的话也会使系统的速度无法可调。3)速度不稳定。环境温度的变化引起泄漏量的变化，致使油液的流量也跟随着产生变化，最终导致执行件的速度不稳定。
b动作控制失效
彩涂板生产动作失控主要表现在液压执行件不按预设的程序或机组工艺要求完成起始和结束动作，甚至会出现意外的动作或动作不平稳。
(1)执行件不能起始动作。引起这种现象的主要是因为液压系统的换向阀不能正常开启，具体原因有以下几种:换向阀阀芯卡死或其顶杆弯曲;换向阀电磁铁烧坏或电线松脱;控制继电器失灵;串联在回路中的截流阀、调速阀卡死;液压动力没有从卸载状态转人工作状态;负载部分有异常，无法将其推动等，都会使动作无法正常启动。
(2)执行件不能结束动作。引起这种现象主要是因为液压系统的换向阀不能正常关闭，具体原因有以下几种:换向阀卡死或弹簧折断，致使阀芯不能复位;执行开关和继电器的故障致使换向阀的电信号未能及时消失等，都会使动作无法正常启动结束。

(3)意外动作。意外动作主要是由换向阀和电信号故障引起。换向阀故障引起的有换向阀的阀芯装反，如两位换向阀的开闭位置颠倒了;换向阀内部磨损严重等。电信号故障引起的是电磁铁得到了错误的电信号，引起误动作等

A. speed control failure



It can be said that the failure of production speed control of color coated sheet is caused by crawling, slow speed, unstable speed and non adjustable speed. (1) Crawling. When the pressure cylinder is low, the phenomenon of continuous motion is called creeping. The phenomenon of color coated plate production is caused by many factors, such as: air is mixed in the system, the compressibility of air makes the hydraulic oil compressible, resulting in the reduction of the stiffness of the oil, causing the creeping phenomenon of the actuator such as the oil cylinder. In addition, crawling phenomenon can also be caused by other reasons, such as: the pressure is too low; the pressure and flow in the system have too large fluctuations; the leakage caused by the heavy wear of the actuator; circuit abnormalities and other reasons will make the movement of the actuator uneven, and eventually lead to the crawling phenomenon of the system speed.

(2)。 1) It's slow. Wear of hydraulic pump, directional valve and other actuators, too low regulating pressure of overflow valve, insufficient opening of shut-off valve or speed regulating valve, and too large load of the system will cause the speed of the system to decrease. 2) The speed cannot be adjusted. Flow control valve stuck; manual speed control valve damage are naturally caused by the speed can not be adjusted. In addition, if the electric signal of the electro-hydraulic proportional speed control valve can not be adjusted, the speed of the system can not be adjusted. 3) The speed is not stable. The change of the environment temperature causes the change of the leakage, which leads to the change of the oil flow and the instability of the speed of the actuator.

B. failure of action control

The out of control action of color coated plate production is mainly manifested in that the hydraulic actuator does not complete the start and end action according to the preset procedure or the process requirements of the unit, and even unexpected action or unstable action may occur.

(1) The actuator cannot start the action. The main reason for this phenomenon is that the directional valve of the hydraulic system can not be opened normally. The specific reasons are as follows: the spool of the directional valve is stuck or its top rod is bent; the electromagnet of the directional valve is burnt out or the wire is loose; the control relay is out of order; the shut-off valve and speed regulating valve in series in the circuit are stuck; the hydraulic power is not transferred from the unloading state to the working state; If the load part is abnormal and cannot be pushed, the action cannot be started normally.

(2) The actuator cannot end the action. The main reason for this phenomenon is that the directional valve of the hydraulic system can not be closed normally. The specific reasons are as follows: the directional valve is stuck or the spring is broken, resulting in the valve core can not be reset; the failure of the executive switch and relay causes the electrical signal of the directional valve not to disappear in time, which will make the action unable to start normally.

(3) Unexpected action. The unexpected action is mainly caused by the failure of directional valve and electrical signal. For example, the opening and closing position of the two position directional valve is reversed; the internal wear of the directional valve is serious. The fault of electric signal causes the electromagnet to get the wrong electric signal, which leads to misoperation