机设基本[下]作业解答.ppt

2-1. 已知Fa=2000N,Fr=6000N,求轴的危险剖面上循环变应力σmax,σminσm,σa及γ ∴σmax=51.558,σmim=-49.06,σm=1.258,σa=50.3及γ=-0.95 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 2-3解: Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 2-4.已知r/d=3/45=0.0667,D/d=54/45=1.2,查表求ασ 由表知D/d=1.2, r/d=0.04时, ασ=2.09, r/d=0.1时, ασ=1.62 用线性查值法查得ασ=1.88. 查图2-8得qσ=0.78, 解得零件极限应力图坐标为A(0,88),D(141,69.5),C(260,0) 线性查值法:见图 由图2-9得εσ=0.83 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 2-5 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 4-2解:如图已知QP=4000N,F=2000N 4000 tgθb=Cb=tg30o=0.577, tgθm=Cm=tg45o=1 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 如图所示，已知铰制孔螺栓铰孔直径d0=13mm,若螺杆与孔壁的挤牙强度足够，试求作用于该悬壁梁的最大作用力P,已知?s=600MPa，nт=2.5 将P向螺栓组型心简化，得P与T T=PX200 由P力引起的横向力，对每个螺栓是相等的，即 由T力矩引起的横向力，则 4-3 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 4-4 凸缘联轴器图14-2a，用普通螺栓六个联接，分布在D=100mm 圆周上，接合面摩擦系数f=0.16，防滑系数Ks=1.2，若联轴器传递 扭矩150N·m，试求螺栓螺纹小径。（螺栓 ） 解：六个螺栓承受的横向载荷 单个螺栓承受的横向载荷 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 需要的预紧力 螺纹小径 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 5-1 如图所示凸缘半联轴器及圆柱齿轮，分别用键与减速器的低速 轴相联接。 选择键，并校核强度。轴为45钢，T=1000N·m，齿轮为键钢， 半联轴器为灰铸铁，工作时有轻微冲击。 解：查手册，选键 =70处， ，A型键 L=110或125 =90处， ，A型键 L=80 70： Evaluation only. Created with Aspose