I. Introduction Throttle valve through the flow through the cross-sectional area of ​​the change to regulate the flow through the implementation of institutions to achieve the speed of the stepless speed regulation. Throttle structure is simple and compact, in the general oil enough to meet the needs of work. However, the pressure difference before and after the throttle changes with the load changes, the load changes affect the speed stability, and therefore not suitable for large load changes or higher speed stability of the hydraulic system. Second, the fault principle (A) failure of throttling effect, so that the implementation of components can not change speed or speed range is not large, completely closed, the cylinder does not move This failure phenomenon is manifested as: when the handle is adjusted, the throttle outlet flow does not follow Release or tighten the handle changes, so that the speed of the actuator is always maintained at a certain value (with the throttle valve spool at what opening position may be), completely shut down, the actuator does not move. The main reasons are: ①due to dirt stuck in the oil spool or plug the throttle. ② due to the spool and valve body shape position tolerance is not good, such as missing a cone, causing hydraulic clamping, resulting in throttle adjustment failure. ③ due to the valve body and the valve body with the gap is too small or too large, resulting in a large number of valve core stuck or leakage, resulting in throttling regulatory failure. ④ spool and valve holes appear inside and outside the cylindrical scratches scratches, so that the valve core movement is not flexible, or stuck, or large leaks, resulting in throttling failure. (B) Although the flow rate can be adjusted, but the adjusted flow instability, so that the implementation of the instability of the speed components, especially in the flow adjustment range of the minimum (minimum steady flow) and the throttle valve import and export of the minimum work Especially when the pressure value of the phenomenon of this failure phenomenon: But the throttle adjustment in a throttle opening, and tighten the adjustment screw, the outlet flow is still changing, making the implementation of components of the movement speed When slow, or gradually slow down, or gradually increase and sudden jerk instability phenomenon. The main reason causing the instability of the flow is the "plugging" in the throttle opening, the looseness of the locking device, the high oil temperature and the large variation of the load pressure. The details are as follows: ①The large leakage of the throttle valve causes unstable flow. ② into the system of air, so that the compressibility of the oil greatly increased, sometimes compressed, sometimes released, the flow is not stable. ③ throttle spool gap seal, the annular gap flow equation shows, there must be internal leakage. ④ large changes in system load, resulting in changes in the working pressure of the cylinder, while the throttle valve speed regulator as there is no pressure feedback compensation device. ⑤ oil temperature increases with the increase of running time, a corresponding reduction in oil viscosity, increased flow through the throttle opening, but may also be reduced due to an increase in internal leakage, flow instability phenomenon. ⑥ throttle valve adjusted and locked, due to mechanical vibration or other reasons, will make the locking screw loose, so that the throttle opening changes, causing flow changes. (C) of the external leakage (D) within the leak Leakage is mainly due to the throttle valve spool and the valve hole is too large or serious wear and tear during use, as well as the valve plug and valve hole with a groove (especially Is the axial groove), as well as oil temperature is too high and other factors.
Rubber Flooring Mat,Rubber Floor Tiles ,Rubber Floor Covering ,Soft Flooring
Sports Floor,Plastic Floor Co., Ltd. , http://www.nbpvcsports.com