screwjoints讲解.pptVIP

§ 11-1 联接类型和螺纹联接简介Types of the joints and screw joints 联接类型 Types of the joints 螺纹联接简介和应用 Screw joints and their applications 一、联接类型 Types of the joints 螺纹联接通常有以下几种形式： 螺栓联接 Bolt joints 双头螺柱联接 Stud joints 螺钉联接 Cap screw joints 紧定螺钉联接 Setscrew joints 工程中应用如下： § 11-2 螺纹联接的拧紧和防松 Tightening and preventing unscrewing of screw joints 一、螺纹联接的拧紧Tightening of screw joints 二、螺纹联接的防松 Preventing unscrewing of screw joints § 11-3 螺栓组联接的受力分析Forces in group of bolt joints 一、任务和假设 Task and assumptions 二、 Forces in group of bolts subject to tensile strain 受拉螺栓组联接受力分析  1. The group of tensile bolts bears transverse forces 受拉螺栓组联接承受横向力 2. The group of tensile bolts bears rotating torque 受拉螺栓组联接承受旋转力矩 3. Group of tensile bolts bears axial force受拉螺栓组联接承受轴向力 4. Group of tensile bolts bears inverting moment受拉螺栓组联接承受翻转力矩 三、Forces in the group of shear bolts  Loads are transmitted by sheared bolts and pressing each other between bolts and parts jointed 受剪螺栓组联接受力分析 受剪螺栓组联接是靠螺栓受剪以及被联接件和螺栓之间的相互挤压传递载荷。 1. Group of shear bolts bears transverse force 受剪螺栓组联接承受横向力 2. Group of shear bolts bears rotating torque 受剪螺栓组联接承受旋转力矩 §11-4 Strength calculations for single bolt 单个螺栓强度计算 Tight bolts subject to preload and operating load预紧力和工作载荷联合作用的紧螺栓 §11-5 Methods of increasing joint strength of bolts 提高螺栓联接强度的措施 2. Improving method (Reduce pitch difference between nut and bolt) 改善办法(减小螺距差) Concrete measures具体方法如下 Design example of bolt joints螺栓联接设计实例 分析：此螺栓组采用受拉螺栓、并有纵向工作载荷，设计公式如下： 查手册：取M18螺栓或者取M20螺栓By handbook take bolt M18 or bolt M20 思考题 思考题 思考题 思考题 思考题 请见实例 实例 动画模拟 实例 一、 Improving load distribution among thread teeth 改善螺纹牙间载荷分布 1. Load distribution among thread teeth is unniform 螺纹牙间载荷分布的不均匀性. 螺杆和螺母拧紧后，螺杆受拉，螺距增加；而螺母受压，螺距减小，造成一定的螺距差。 这种螺距差在螺杆与螺母开始旋合的第一圈最大，以后各圈迅速减小，造成第一圈螺纹受力最大，以后各圈螺纹受力迅速减小，8~10圈以后螺纹牙几乎不受力。