凸轮的压力角,既是影响凸轮机构的效率,又是影响凸轮机构结构紧凑性的几何参数。这两种影响是互相矛盾的:压力角越大,凸轮机构的效率越低,但机构紧凑。因此,压力角既不能过大,又不能过小。过大导致凸轮机构自锁,过小,会使凸轮机构尺寸太大。显然,压力角过大比过小的危害性更严重。在设计中,可利用许用压力角[α]来限制最大 The pressure angle of the cam not only influences the efficiency of the cam mechanism but also affects the compactness of the cam mechanism. These two effects are contradictory: the greater the pressure angle, the lower the efficiency of the cam mechanism, but the mechanism is compact. Therefore, the pressure angle can neither be too large nor too small. Too large to cause the cam mechanism self-locking, too small, will make the cam mechanism size too large. Obviously, the pressure angle is too large and the danger is more serious. In design, the allowable pressure angle [α] can be used to limit the maximum