# Design and Analysis of Internal-External Composite Meshing Hy-Vo Chain
## 5 Multi-Body Dynamics Experiments
### Contact Analysis  
In this paper, we use the contact force between the target chain link and the drive sprocket to roughly represent the meshing force between the Hy-Vo chain and the sprockets. As Figure 16 demonstrates, the contact forces appear periodically with the simulation time, and the meshing impacts occur during a period of time at the beginning and end of meshing. This coincides with the time of the contact and separation between the chain link and the sprocket tooth. To analyze the effects of the meshing mechanisms on the meshing impacts under different speeds, we extract the values of the maximum meshing impacts and the values of the average meshing impacts of the three groups at different speeds from Figure 16, as Figure 17 displays. Figure 14: Analysis based on the maximum fluctuation difference: (**a**) maximum fluctuation differences; (**b**) improving rate of meshing performance. Figure 15: Analysis based on the standard deviation of the fluctuations: (**a**) standard deviation of fluctuation; (**b**) improving rate of transmission stability. Figure 16: _Cont_. Figure 16: Meshing force between the target chain link and the drive sprocket: (**a**) 1000 rpm; (**b**) 1500 rpm; (**c**) 2000 rpm; (**d**) 2500 rpm; (**e**) 3000 rpm; (**f**) 3500 rpm; (**g**) 4000 rpm; (**h**) 4500 rpm; (**i**) 5000 rpm; (**j**) 5500 rpm; (**k**) 6000 rpm; and (**l**) 6500 rpm. We know from Figure 17a that the maximum meshing impact of the external meshing Hy-Vo chain system at most speeds is the smallest, and that of the mixed assembly Hy-Vo chain system at most speeds is the greatest. From Figure 17b, we can know that, at the speeds of 1000 rpm, 1500 rpm, 3500 rpm, 4500 rpm, and 5500 rpm, the average meshing impact of the internal-external composite meshing Hy-Vo chain system is the smallest. At the speeds of 2500 rpm, 3000 rpm, 4000 rpm, 6000 rpm, and 6500 rpm, the average meshing impact of the external meshing Hy-Vo chain system is the smallest. When the speed is equal to 6000 rpm, the average meshing impact of the mixed assembly is the smallest. As a result, there are no sufficient data to support that the internal-external composite meshing mechanism can effectively mitigate the meshing impact between the Hy-Vo chain and the sprockets. To further obtain the effect degree of the internal-external composite meshing mechanism on the reduction in the meshing impact, we take the meshing impact of the external meshing Hy-Vo chain system as the benchmark and calculate the decrease rates of the other two chain systems at all speeds, as Figure 18 demonstrates. Figure 17: Meshing impacts: (**a**) maximum impact curve; (**b**) average impact curve. Figure 18: Decrease rate of meshing impacts: (**a**) decrease rate of maximum impact; (**b**) decrease rate of average impact. As Figure 18 displays, whether for the maximum meshing impact or the average meshing impact, the performance of meshing impact at most speeds will not be improved by using the internal-external composite meshing Hy-Vo chain or the mixed assembly Hy-Vo chain, but will instead be worsened by using them. Especially for the mixed assembly Hy-Vo chain system, the decrease rate of maximum impact can be as low as \(-369.95\%\), and the decrease rate of average impact can be as low as \(-126.20\%\). This means that, if using the mixed assembly Hy-Vo chain, the maximum meshing impact will be increased by up to \(369.95\%\), and the average meshing impact will be increased by up to \(126.20\%\). Based on the values in Figure 18, we can easily obtain that the mean decrease rates of maximum impact for the internal-external composite meshing Hy-Vo chain system and the mixed assembly Hy-Vo chain system are \(-51.24\%\) and \(-156.00\%\), respectively, and the mean decrease rates of average impact for them are \(-6.19\%\) and \(-31.18\%\), respectively. Therefore, on the one hand, the classical design approach to the internal meshing profile of the mixed assembly Hy-Vo chain is false.