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Spiral bevel gears which have high contact ratio, high load capacity, and smooth transmission are usually used on augular transmission. the powder metallurgy modify spiral bevel gears , are cheap and can be mass-produced, suitalbe for small and medium sized equipment, like electrical tools and gardening tools.
The purpose of this study is designing powder metallurgy modify spiral bevel gear and building analysis method for it,so the influences of assembly errors, the influences eccentric errors and the load characteristics in contact process can be confirmed.
To avoid interference happen between gear and model, the spiral bevel gear is desgin by axis-rotating spherical involute. The pinion is modified to improve the contact stress. Also, developing the mold stripping anaylsis method can find the mold stripping angle.
The tooth contact anaylsis (TCA) of spiral spherical involute bevel gear, is based on characteristics of normal vectors, can simplify the solving procedure. This method can ues on the gear pair with assemble errors and eccentric errors, finds contact variety on tooth surface and transmission error.
The load tooth contact analysis (LTCA) is based on influnce coefficinet method, included tooth contact, tooth bending, shaft bending, and shaft twist, to determine tooth contact stree, load transmission error, and load sharing.
In this study, a spiral bevel gear pair is desgined by the requirement of cooperation vendor, and confirm it can strip. In addition, the gear pairs use TCA to find the influences of assembly errors. The result show the contact position of the tooth pair due to the offer errors caues is the most sensitive, the next is due to mounting distance of the gear and the pinion. The shaft angles error slightly affects the conatact position. The curve of transmission error is parabolic curve, even gear pairs have assembly errors. But the curve of transmission error of the tooth pair wiht eccentric error is similar to sine curve combined by parabolic curves. The amplitude of sine curve is greater than the amplitude single parabolic curve.
The LTCA result of gear pairs show that large assembly errors cause concentrated contact stress still occurs nearby the contcat begin position and the conatcat end position. The assembly errors sightly affect the LTE curve, and affect the contact begin angle and the contact end angle. Because of the gear pairs support by cantilever beam , the contact stress on right tooth side need to compare with left tooth side. The result show that the appropriate modify make the contact stress on both side almost same. | en_US |