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近来,液压随动装置在金屬切削机床中得到越来越广泛的应用淙灰呀洺霈F了不少新型的随动系統,如:噴嘴——挡板、針閥、电液控制等;但滑閥式液压随动系統毕竟是目前应用最广而发展也比較成熟的一种。滑閥式液压随动系統所能保証的加工精度目前还不够理想,一般生产中应用的滑閥式液压随动装置可保証士0.05毫米左右的加工精度。如果抛开其他工艺因素对加工精度的影响,而主要研究液压随动系統的精度时,一般可以用靜态条件下,系統在不同輸入信号作用下(阶跃、等速、等加速运动)的誤差、速度放大系数和刚度系数做为衡量系統优劣的参数。在提高液压随动系統工作精度的同时,会出現稳定性降低的情况,所以,选定一种同时具备較高精度和較好稳定性的液压随动系統是一項很有意义的工作。本文試就两种两級放大液压随动系統的靜态特性和稳定性做一綜合分析,並与同类型滑閥一級放大的系統进行对比,从理論上闡明系統的基本特性。在以下分析中,假設初始条件——即系統的速度和負载的初始值为零。认为液体流經滑閥工作边时的特性符合伯努里方程,並对各非綫性影响进行綫性化。同时,认为系統油液的温度不变,压力恒定,忽略液压冲击的影响。
Recently, hydraulic follower devices have become more and more widely used in metal cutting machine tools. Many new types of follow-up systems are available, such as: nozzles - baffles, needle valves, electro-hydraulic controls, However, spool valve hydraulic servo system, after all, is currently the most widely used and the development of a more mature. The spool valve hydraulic servo system can guarantee the processing accuracy is not ideal, the general production of the spool valve hydraulic servo device can guarantee about 0.05 millimeter machining accuracy. If we put aside the influence of other factors on the machining accuracy and mainly study the accuracy of the hydraulic servo system, we can generally use the static conditions, the system under different input signals (step, constant velocity, etc.) Error, speed amplification factor and stiffness coefficient as a measure of system parameters. While improving the work accuracy of the hydraulic servo system, the stability will be reduced. Therefore, it is very meaningful to choose a hydraulic servo system with high accuracy and good stability. In this paper, a comprehensive analysis of the static characteristics and stability of two types of two-stage hydraulic servo system is made and compared with the first-stage amplification system of the same kind of spool valve. The basic characteristics of the system are clarified theoretically. In the following analysis, assume that the initial conditions - that is, the initial value of the system speed and load is zero. It is considered that the behavior of the fluid flowing through the working side of the slide valve conforms to the Bernoulli equation and linearizes the various non-linearities. At the same time, that the temperature of the system oil constant pressure constant, ignoring the impact of hydraulic impact.