Dynamic Modeling And Analysis Of Globoidal Indexing Cam System With Steel Ball

Globoidal indexing cam mechanism is a key functional part of all kinds of automatic machines. With the promotion of produce efficiency, the rotational speed of machines goes higher and higher. A new type of Globoidal indexing cam mechanism based on steel balls which is engaged with the cam at one single point is presented. Compared with other types of indexing cam, it has an advantage in wide applicability, high transmission efficiency and precision, minor abrasion, superiority in performance of high rotational speed and better heat quality. The "rotation to rotation" transmission mechanism is rarely used in good-sized numerical control machines at present. It is of vital meaning that studying at the new mechanism to promote the cam academic level and advance the manufacturing. This academic dissertation establishes the model of the cam mechanism and analyses the dynamics response of the cam mechanism, the main work is listed as follows:1. The constraint form and the motion law's characteristic value of the Globoidal indexing cam are analyzed, and the motion laws which are most widely used are compared and studied, the principle of how to select the cam mechanism motion law is presented.2. The engage theory of the Globoidal indexing cam is studied based on the mathematic means of spatial rotation transformation tensor and space differential geometry theory. The mathematic model of the Globoidal indexing cam with double-arc cross-sectional shape working raceway is established by mathematic methods of rotary motion group and round vendor functions. This model genuinely achieves the point engagement transmission between the cam and indexing plate by controlling the contact angle of raceway and the steel balls. In addition, the geometric model is set up in Pro/e and the stress angle is analyzed, which provides a foundation for the followed dynamics studies.3. Based on the geometric model, this dissertation has studied and build the elastodynamics model of the Globoidal indexing cam, analyzed the dynamics characteristic of every component by means of Lagrange equation., and established the dynamics equation of the whole system, solved the equation using the modal superposition method. Finally, the result is compared with the line engagement indexing cam, the superiority is presented.4. This dissertation has analyzed the curvature of working surface of the Globoidal indexing cam, compared and studied curvature of three motion laws of revised isokinetic, revised trapezoidal acceleration and revised sine acceleration. In addition, this topic studied the contact stress and deformation of the Globoidal indexing cam using Hertz theory, presented the factors influencing the contact stress and deformation.