x= (rb+s) sinΦ       

     y=(rb+s)cosΦ                                 (3) 

Consider the impact roller; the equation of the actual profile is follow. 

Where rr is the roller radius, the symbol negative is the internal offset curves, the symbol positive is the external offset curves. 

The θ can gain from:     It not only can greatly improve the design speed, accuracy and design automation design, but also apply the simulation technology and modeling technology to analyze three-dimensional dynamic, by the parallel composite design of the cam mechanism. The cam base circle radius of 1, 2 and the corresponding coordinates of points is shown in Fig 7. 

           Fig.7  Data display window 

   Click the start button can enter the interface window of animation, to continue the animation, and then click this button. To exit the animation interface, click exit. It is the all simulation process. 

Summary 

   The design take type of parallel combination of the mechanical of innovation system as theoretical basis, Ⅱbase on the development platform of VB language, it can realize dynamic simulation for the cam mechanism by the compile program, the building system can gain the parametric design and motion simulation of arbitrary trajectories of cam mechanism. 

The Parametric Design and Motion Analysis about Line 

Translating Tip Follower Cam Mechanism Based on Model 

Datum Graph 

SUN Jianping ,TANG Zhaoping

School of Traffic & Transportation Engineering, Central South University, Changsha Hunan, 410075, China

 School of Mechanical and Electrical Engineering, East China Jiao Tong University, Nanchang Jiangxi, 330013, China 

Abstract 

   Cam mechanism can get the expected movement law by means of higher pair touch drive follower. This paper used Pro/E’s datum-graph function, to create the follower’s displacement line graph, and to control cam profile by using the displacement line graph, the line translating tip follower cam mechanism was wholly parametric designed. The system can provide 16 kinds of typical combination motion law for users. The system can generate automatically cam profile according to the parameter imported by the consumer. Furthermore, using the technology of virtual assembly and motion simulation, the visible assembly structure analysis and performance evaluation can be realized in design phase. 

Keywords: Line Translating Tip Follower Cam Mechanism; Pro/E; Parametric Design; Motion simulation analysis 

1. The train of thoughts to build model 

    By means of cam profile’s change, cam mechanism’s follower can reach the expected or any complex movement law, so as to cam mechanism is widely applied in various machinery and automatic control equipments [1]. The difficult point of full parameterize design is that cam should generate automatically different profiles according to different motion laws of follower [2].

Cam mechanism’s motion process is made up of four stages as rise travel, farthest dwell travel, return travel and nearest dwell travel, as shown in Fig. 1. In rise travel or return travel, there are some typical kinds of motion laws as constant velocity,constant acceleration and constant deceleration, cosine acceleration and sine acceleration, so cam mechanism products 16 kinds of motion combination. This paper took rise-travel and return-travel as design parameters, and gave 1, 2, 3 and 4 as their values to correspond respectively the four kinds of motion laws. So that only 8 corresponding motion curves were needed to create for program calling according to  different parameters. Furthermore cam profile can generate automatically for 16 kinds of typical combination motion law.