Taking the helical gear pair of a reduction box of an electric vehicle as the research object, the influence of gear modification technology and gear parameters on its meshing performance was investigated by using KISSsoft software, and a preliminary optimized modification scheme was obtained to reduce transmission error and Hertz contact stress. The main conclusions are as follows:
(1) Proper increase of helical gear tooth width and pressure angle is beneficial to improve transmission efficiency and Hertz contact stress of gear pair, but will increase transmission error; Proper helix angle can reduce the transmission error and Hertz contact stress of helical gear pair, but the greater the helix angle, the lower the transmission efficiency.
(2) On the premise of tooth top modification of long tooth profile (linear, involute, circular arc, polyline circular arc), it is recommended to modify the large and small gears at the same time or only the large gear. If only the small gear is 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 increase the strength (life) of the helical gear, but also to reduce the transmission error; Tooth alignment modification is mainly to reduce the transmission error, that is, to reduce the internal dynamic excitation of helical gears, but also to reduce the Hertz contact stress.
(4) It is necessary to consider the possibility of compound modification when only large gears are subject to long tooth profile tooth top modification (linear, involute, circular arc, broken arc).
(5) From the point of view of reducing Hertz contact stress and transmission error of the helical gear, among all the preliminary optimized modification schemes of the helical gear pair, the linear effect of the tooth top of the long tooth profile is the best when the large and small gears are modified simultaneously; The effect of tooth profile drum modification is better only for big gear or small gear; The effect of tooth profile bulge is the best when the gear is only modified.
(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 significantly improved.