在平面连杆机构中，机构的传动角越或压力角越，则机构的传力性能越好。在机构的传动角<img src="https://storage.tutusouti.com/pzst/question_bank/res/29/c8/29c85b74385a2adb56094d91a5a7d9b1ee79ad56.jpg?x-oss-process=image/sharpen,200,https://storage.tutusouti.com/pzst/question_bank/res/a2/be/a2bec751d48de91c201623e9336d9a598134bac4.jpg"/>= 时，机构存在止点位置。。<br/> [填空(1)]