## 4 Discussion  
The diagrams (Figure 6) demonstrate that when manufacturing the ring using the H9 fit and the cam using k9, the manufacturing clearance for transmissions with intermediate rolling elements and free cage (IREFC) varies from 0.005 mm to 0.017 mm. This is less than the clearance that emerges in the engagement when manufacturing profile disks, according to the 7 th tolerance grade, as is carried out at enterprises. Such fits can be assigned to the cycloidal profiles of the disks if other options are not considered. Manufacturing the cam profile with the js9 fit results in the obtainment of a manufacturing clearance ranging from 0.025 mm to 0.086 mm. This exceeds the parameters currently provided at the manufacturing site and is not acceptable.  
In this case, it is important to bear in mind that the obtained clearance ranges represent the field of a possible location of real profiles of cycloidal wheels and the rolling elements. At the same time, the cycloidal surfaces of the disks and the cylindrical surface of the rolling elements are not equidistant from their theoretical profile.  
Figure 8: Change of clearances in the engagement when manufacturing the external profile disk by the **Js** fit.  
Figure 7: Change of the clearances in the engagement when manufacturing the external profile disk by the **K** fit.  
When manufacturing the ring with the K9 fit and the cam with h9 (Figure 7), the manufacturing clearance for transmissions with IREFC changes from \(-0.001\) mm to \(0.004\) mm. This is also less than the clearance currently obtained at enterprises when manufacturing profile disks according to the 7 th tolerance grade. However, the minimum value of the clearance has turned out to have a \"\(-\)\" sign, that is a negative allowance may form instead of a clearance in the engagement. However, for the combination of fits under study, this is admissible since the negative allowance is \(1\)\(\mu\)m and can be eliminated during the mechanism roll-on due to roughness crumpling. If the cam is manufactured with the is9 fit, then instead of the clearance, it is possible to obtain only a negative allowance that can be sufficiently large, varying from \(-0.014\) mm to \(-0.026\) mm, which is not acceptable.  
Figure 8 shows that the manufacture of the ring with the Js fit does meet the purpose of the research. First, in this case, a large negative allowance of up to \(0.015\) mm can arise. Second, a very large clearance of up to \(0.079\) mm may appear.  
In this way, to design and manufacture cycloid profile disks, it is possible to recommend K9 fits for the ring, h9 for the cam and h6 for the rolling elements. In case of such a combination of fits, the transmission accuracy increases since there is the possibility of the emergence of an insignificant negative allowance. Such combination of fits decreases the clearance in the engagement, even compared to the more precise manufacture of profile disks. However, if the dimension distribution law within the tolerance zone is considered when manufacturing these disks, then \(90\%\) of the parts will be produced without a negative allowance and this will provide a more precise engagement of transmissions with IREFC.  
The considered results are related to the accuracy of the manufacturing of the surfaces of parts that contact and create the engagement of transmissions with intermediate rolling elements (IRE). At the same time, the mutual bracing of these surfaces can be different. The cycloidal surfaces of the disks must theoretically be parallel to the cylindrical surface of the rolling elements. In fact, these surfaces may not be parallel to each other. The problem of studying the mutual bracing of the surfaces of parts in the engagement of transmissions with IRE seems to be an interesting task for further research.