Non-full-symmetry involute gear, gear cutting hob special for same, and machining method of non-full-symmetry involute gear

Abstract

The invention discloses a non-full-symmetry involute gear, a gear cutting hob special for the same, and a machining method of the non-full-symmetry involute gear. The method includes five steps which include: preparing a gear blank which can be used for hobbing, selecting the gear cutting hob special for the non-full-symmetry involute gear, and the like. The axial tooth profile of the gear cutting hob comprises a left tooth profile and a right tooth profile, wherein the left tooth profile comprises linear segments HI, IJ and KL and an arc-shaped segment JK, and the right tooth profile comprises linear segments PO, ON and ML and an arc-shaped segment NM. The end face tooth groove tooth profile of the non-full-symmetry involute gear comprises an involute segment AB, an involute segment EF, a tooth groove left tooth root curve BG and a tooth groove right tooth root curve GE. The non-full-symmetry involute gear has the advantage that the left side and the right side of the teeth of the gear can have different tooth root bending strength. The gear cutting hob can obtain different involute starting points of the a left tooth face and a right tooth face and different tooth root curve curvature radiuses while the left tooth face and the right tooth face of the gear are allowed to have different grinding amount, and defects such as grinding bosses are avoided favorably.

Description

technical field [0001] The invention relates to an asymmetrical involute gear, a special cutting tool and a processing method thereof. Especially suitable for intermediate idlers or planetary gears whose teeth are subject to bidirectional bending loads. Background technique [0002] Gear transmission systems often use intermediate idler gears or planetary gears that mesh with two gears at the same time. Because their teeth are subjected to bidirectional bending loads, the tooth roots of the gears are most likely to be bent and broken. For example, in GB / T 3480-1997 " Involute Cylindrical Gear Loading Capacity Calculation Method" P56 stipulates that for gears subject to symmetrical bidirectional bending (such as intermediate gears or planetary gears), when designing, the bending fatigue limit value of the gear should be multiplied by a coefficient of 0.7 as this type of gear. Endurable bending fatigue limit. In addition, the left and right tooth surfaces of the intermediate...

AI Technical Summary

Problems solved by technology

In addition, the left and right tooth surfaces of the intermediate idler gear or planetary gear mesh with two different gears respectively, so the left and right sides of the teeth of the intermediate idler gear or planetary gear bear different bending strengths, and the starting point of the involute of the tooth surface required for meshing It is also different, and the height of the starting point of the involute directly affects the radius of curvature of the tooth root of the gear, which in turn affects the bending strength of the tooth root of the gear.

[0003] The traditional design method does not consider the difference between the starting points of the involutes on the left and right tooth surfaces, and the designed tooth profile is completely symmetrical to the left and right tooth surfaces and dedendum roots. See GB / T 1356-2001 "Cylinder for General and Heavy Machinery Gear standard basic rack tooth profile "is a completely symmetrical tooth profile. Therefore, in order to ensure that the starting points of the involutes on the left and right tooth surfaces are the same, and have sufficient involute lengths to participate in meshing, the curvature of the root curves of the left and right tooth profiles The radii are small, which further reduces the root bending strength of the intermediate idler or planet gears

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