Taking the helical gear pair of an electric vehicle gearbox as the research object, the KISSsoft software was used to explore the influence of gear modification technology and gear parameters on its meshing performance, and a preliminary optimization modification scheme aimed at reducing transmission error and Hertz contact stress was obtained. The main conclusions are as follows:
(1) The transmission efficiency and Hertz contact stress of helical gear pair can be improved by properly increasing the tooth width and pressure angle of helical gear, but the transmission error will be increased; Proper helix angle can reduce transmission error and Hertz contact stress of the helical gear pair, but larger helix angle is, lower transmission efficiency is.
(2) Under the premise of tooth top modification of long tooth profile (linear, involute, circular arc, broken line circular arc), it is recommended to modify both large and small gears or only large gears. If only small gears are modified, it will only increase the cost and cannot reduce the transmission error and Hertz contact stress.
(3) The tooth profile modification is mainly to reduce the Hertz contact stress on the tooth surface of the gear, that is, to improve the strength (life) of the helical gear, but also to reduce the transmission error; The tooth modification is mainly to reduce the transmission error, that is, to reduce the internal dynamic excitation of the gear, but also to reduce the Hertz contact stress.
(4) When only long tooth profile tooth top modification (linear, involute, circular arc, broken line circular arc) is adopted for large gears, the possibility of compound modification shall be considered.
(5) From the point of view of reducing the Hertz contact stress and transmission error of helical gear, among all the preliminary optimization modification schemes of the helical gear pair, the linear effect of the addendum of long tooth profile is the best when the big and small gears are modified at the same time; When the tooth profile is drum shaped, the effect is better only for big gears or small gears; The drum shape effect of tooth profile is best only for big gear modification.
(6) After preliminary optimization and modification, the meshing performance (oil film thickness, flash temperature, contact temperature, tooth surface load distribution, etc.) of the helical gear pair is obviously improved.