在下行程中开动曲柄压力机,有时滑块会突然加速下落,有时滑块会先向上行程一小段距离然后再向下行程,前者是滑块产生超前现象,后者是滞后现象。特别是在下死点前开动,滞后现象较明显。这两种现象在国内外压力机的使用中都发生过,特别在中、大型压力 In the next trip crank crank press, and sometimes the slider will suddenly accelerate the whereabouts, and sometimes the slider will first up a short distance and then down the trip, the former is the slider leading phenomenon, the latter is the hysteresis. In particular, before starting at the bottom dead center, the hysteresis is more obvious. Both of these phenomena have taken place in the use of presses at home and abroad, especially in the medium and large pressure