| Cycloidal planetary transmission with cycloid-pin gear as the main meshing pair has the characteristics of multi-tooth meshing,and it is easy to transmit motion accurately.At the same time,it has the outstanding advantages of large carrying capacity and high torsion stiffness.It is the main option of the robot's joint drive system.Cycloid tooth profile is the key active surface to achieve motion and power transformation,and has an important influence on the transmission performance of reducer.The theory of cycloid profile optimization and its meshing characteristics have always been one of the research hotspots in the field.Therefore,exploring the new cycloid tooth profile and further studying its meshing characteristics are of great significance for improving the performance of the precision reducer.The main contents of this paper include:(1)A time-varying equidistance cycloid tooth profile with a reasonable distribution of the flank normal gap is carried out.The time-varying equidistance cycloid tooth profile is optimized to reduce the tooth contact stress.Based on VB language,a time-varying equidistant cycloidal tooth profile aided design software is developed.(2)Based on energy law and Hertz contact theory,a calculation model of meshing stiffness of the time-varying equidistance cycloid-pin gear meshing pair is proposed with considering the bending,shearing and compression deformation of the cycloid gear as well as the bending,shearing deformation of the pin.The torsion deformation of cycloid-pin gear under load condition is deduced,and the meshing stiffness and torsional stiffness of single tooth pair at the contact point are given.The influence of tooth profile parameters on the meshing stiffness and torsional stiffness are analyzed,including the eccentricity,pin position radius,pin radius and tooth number.(3)The tooth contact analysis(TCA)model and the loaded tooth contact analysis(LTCA)model of time-varying equidistance cycloid-pin gear meshing pair are established and the meshing characteristics of the meshing pair are analyzed.The contact force and contact stress difference between the time-varying equidistance cycloid-pin gear meshing pair and the traditional modification cycloid-pin gear mesh pair are analyzed under the same target quantity.The contact force and contact stress of the time-varying equidistance cycloid-pin gear meshing pair with eccentricity error is discussed.A tooth modification method is proposed with consideration of the eccentricity error.(4)A cycloidal precision reducer with time-varying equidistance cycloid-pin gear meshing pair was designed and manufactured,and an experimental research on its backlash and carrying capacity was carried out. |
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