旋转周期为曲柄二整周的平面双曲柄四杆机构

Grashof Neutral机构存在切换点(Change point)位置。通常认为机构在其切换点位置具有运动不确定性,其输入输出角速度比为0/0型不定式。根据运动连续性原理和洛毕达极限法则,首次导出了确定此类机构切换点(Change point)角速度比的解析公式。并通过机构运动分析、仿真,以及机构原型的制作和实验,证明:GrashofNeutral机构旋转通过切换点(Change point)时的运动是完全确定的,具其运动周期为驱动曲柄旋转二整周。特别是,当机构相对杆长差取很小值时,将输出有反向自锁特征和近似长停歇期的间歇运动,具有工业实用价值。

PLANAR FOUR-BAR LINKAGES WITH DOUBLE CRANK ROTATING THE DRIVING CRANK TWO TURNS IN A PERIOD OF MOTION

In previous researches, Grashof Neutral mechanisms are usually considered that when they come its change points, the transmission ratio will become to 0/0 and then the output motion will be uncertain. Based on the continuity of mechanism motion and the L'Hospital's theorem, the transmission ratio at the change points of the mechanisms are analytically derived and through the kinematic analysis, simulation and experiments, it is demonstrated that the rotating mechanisms will smoothly pass through its change poins with certain speed and make the driving crank rotate two turns in a period of motion. Further, when the links have nearly same length, the mechanisms can output intermittent motion with a long pause and self-locking characteristic, they are useful for industry.