【作者】 方戍；

【导师】 时轮；

【作者基本信息】 上海交通大学 ， 机械制造及其自动化， 2008， 硕士

【摘要】 随着国内石油开采量的日益增长,油管接箍的需求量越来越大,但特殊扣油管接箍国产化率很低,市场每年都有很大的缺口。油管接箍的主要作用是连接石油管,为保证石油输送的安全性和可靠性,它内螺纹圆度有很高的要求。但油管接箍是典型的薄壁筒状工件,它的内壁加工有一定的难度。宝钢集团是国内特殊扣油管接箍的主要生产厂家,但其在接箍的内壁加工工序中,常发生因夹紧力过大造成内壁圆度超差的情况,严重地影响了生产效率和加工成本。本文就宝钢集团油管接箍车内壁工序中存在的产品合格率过低的问题展开研究,主要进行以下几个方面的研究工作:1.分析油管接箍的加工工艺,得到油管接箍内壁加工工序中合格率过低的主要原因是加工过程中夹紧力不合理。阐述油管接箍加工过程中夹紧力大小的确定原则——既要保证加工过程中油管接箍与机床刀具的相对位置,又要保证夹紧力对油管接箍内壁圆度的影响在公差允许的范围之内。2.在保证加工安全进行的前提下,分析夹紧力和主切削力之间的关系,得到加工安全进行的必要条件;通过实验测量加工过程中主切削力的大小,采用BP人工神经网络建立切削用量与主切削力之间的映射关系,对主切削力进行预测。并利用有限元软件对车削过程进行建模仿真。3.利用功的互等定理,分析油管接箍在内壁加工过程中截面的变形情况,推导夹紧力、接箍内壁夹紧变形以及接箍加工后内壁圆度误差三者之间的关系,建立内壁圆度误差变化的数学模型;利用该模型,分析在保证油管接箍内壁圆度公差要求下夹紧力的取值范围;并通过夹紧过程有限元模型、接箍夹紧过程实验、加工过程实际实验验证理论模型的正确性和准确性。4.在油管接箍截面圆度误差测量实验中,通过多点均布的误差分离方法,对测量数据中的偏心误差和机床主轴径向跳动误差进行了分离,得到了夹紧后内壁截面的圆度误差值。更多还原

【Abstract】 As the demand of the oil tubes’coupling raises sharply, the supply cannot meet the demand now, the oil tubes’coupling is used to joint the oil tube, insuring the gas tightness of oil transport process. As tubes’coupling is a thin-walled workpiece, clamping force affects a lot in the process of turning the inner wall, large force always causes the roundness error out of the tolerance. And the Bao Steel has suffered a lot from this problem, to solve this problem, this paper has made researches around the key issue as follows:1. The principle to determine the clamping force. Suitable size of clamping force has been discussed. The clamping force should be large enough for the security of the processing; however, the size of the force had an upper limit value as considering the roundness tolerance.2. The clamping force and the cutting force model. The relation between the clamping force and the cutting force has been analyzed. Experiments of measuring the main cutting force had been done, and a Back-Propagation Neural Network for forecasting the main cutting force has also been built.3. Roundness model. The relation between roundness and the clamping force has been analyzed; a theory model of the roundness has been built. Experiments and finite element model are made to demonstrate the validity of the model. Three-point symmetry clamp and four-point symmetry clamp has been compared based on the roundness.4. Error separation method for roundness measurement. Some error separation methods for roundness measurement was discussed. Symmetry multipoint error separation method separated the eccentric error and the main axis jerking error from the roundness excellently, and based on this method many experiments for demonstrating the roundness model has been done.更多还原