【作者】 马豫超；

【导师】 胡立德；

【作者基本信息】 重庆大学 ， 机械电子工程， 2002， 硕士

【摘要】 不平衡是指转子相对于其旋转轴质量分布不均匀，改变转子质量分布以使它相对于旋转轴分布均匀是恢复平衡的要求。转子或转轴的制造不可能达到使它们的质量分布相对于旋转轴完全均匀的程度，因此，必然在运行中表现出不平衡。不平衡将会在轴承上产生周期性惯性力，导致轴承疲劳，进而损坏机器设备。平衡（使转子质量分布均匀）的目的并不是完全消除转子不平衡，而是将其降低至容许范围内。恢复平衡需要将一定数量的不平衡量（克?厘米）加在转子固有不平衡量的相反位置上，故平衡的过程涉及不平衡量大小的补偿值的决定，及补偿值的正确定位。曲轴作为结构特殊的刚性转子，在运行中总是与连杆，滑块一起构成一个整体的曲柄连杆机构。由于有往复质量的影响，曲柄连杆机构不可能达到完全的平衡，有其特殊性，因此其理论在动平衡领域内占有特殊地位。本论文针对摩托车发动机曲柄连杆机构为研究对象，对曲柄连杆机构动平衡的测试提出了一种新方法，并对其数字化测试装置进行了深入研究，完成的主要工作及取得的成果如下：首先，对动平衡理论进行了详细的探讨，论述了不平衡产生的原因，不平衡种类及转子在不平衡量产生的惯性力激励下的运动规律，并对曲轴这一结构特殊的刚性转子的平衡理论进行了阐述，重点研究了曲柄连杆机构这一往复式机械构件的力学特性。 其次，通过对当前国内外曲柄连杆机构动平衡实验的现状及其存在问题的分析研究，提出了一种新的测试方法：在工作原理上采用硬支承型测力式动平衡机，在测量方法上应用互成900的两点测量来失量合成任意一点旋转惯性力大小及方向，这也是也是其不同于以往试验机的最大之处。提出了新型实验方法所采用实验装置的测试原理和数学模型。第三：得到了一个结论：在设计制作曲柄连杆机构动平衡测试装置时，必须考虑这一受力情况，即连杆在作平面运动时，其自身的惯性力（不通过回转中心）与汽缸对活塞的反作用力二者之间形成的力偶将会对弹性支承元件产生扭矩的作用。最后，对测试过程中数据采集、数据定标、数据处理进行了详细研究，利用强大的Microsoft Visual C++ 6.0中的APPWIZARD与IPC5432数据采集卡自带的IPC5432.OCX应用程序接口控件开发适用于本试验机的测试应用程序。更多还原

【Abstract】 Unbalance means the non-uniform distribution of the mass of a rotor about its axis of rotation. Redistributing the mass (weight) more uniformly is necessary to restore balance. No rotor, or shaft can be manufactured with perfectly uniform weight distribution. Hence, all such components will display some degree of unbalance. Unbalance damages machinery by imposing cyclic forces on bearings and shafts that lead to fatigue failure. The purpose of "balancing"-of restoring uniformity of mass distribution insofar as possible-is not to eliminate all rotating system unbalance, but to bring it down to a tolerable level. To restore balance, that same number of gram-centimeters must be added to the assembly 180 degrees away. The balancing process, then, involves determining the number of gram-centimeters to be compensated for, and locating the proper angular position at which to add such compensation.As a rigid rotor with special configuration, the crank is always integrated with its accessory components such as shaft and piston when it is under working conditions. So, with the reciprocal mass of this combinational equipment, the dynamic unbalance of the crank has the special status in the field of the unbalance theory. This dissertation has presented a new method on the measuring and checking procedures of the dynamic unbalance of the motorcycle crank and made a deep research on its measuring device. What have been done is as follows:Firstly, the dissertation has thoroughly discussed the basic theory of rotor unbalance such as its varieties ，characters and rules of the movement which is under the excitation of the inertial force and inertial moment induced by the unbalance mass. It also has deeply expounded the dynamic mechanics of the specially formed components —crank, especially in the area of the crank integrated with shaft and piston. Secondly, based on the defects of the uptodate balancing machine which were employed in the motorcycle manufacture plants, this dissertation has presented a new method on the means of checking unbalance mass of the motorcycle engine crank set. It has adopted the hard-bearing balancing machine as the prototype，utilized tow group of resistance sensors placed in vertical direction with one another to pick up the information which stand for the inertial force of the motor engine crank set when it is running. Furthermore, on the theoretics of the balancing machine and associations with the practicalities of the motorcycle crank, it has reasoned out the test principles and<WP=6>mathematic model of the unbalance mass checking device of the motorcycle engine crank set, which is supported by the new method.Thirdly , a conclusion has been settled down in this dissertation: Because the shaft inertial force vector do not pass the center of the rotating center of the system, there is a moment generated by the shaft inertial force and the counterforce of the cylinder wall to counterbalance the pressure which is imposed by the piston, so, it is important to consider the tortile effect on the flexible supporting component of the balancing machine dedicated to motorcycle crank set, which is originated by the moment. Finally, this dissertation has made an exhaustive research on the data sampling and data processing. Based on the powerful APPWIZARD of the Microsoft Visual C++ 6.0 and the IPC5432 controls used as the application interface between the computer and the multifunctional data sampling board, this dissertation has developed the unbalance mass checking software which is applied into this balancing prototype machine.更多还原