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(3)四挡齿轮为斜齿轮,初选螺旋角?3?4=22°
Z3Z(1.12) ?i41
Z4Z2=1.56?14 31 =0.704
A?mn?Z3?Z4? (1.13)
2cos?3?4由(1.12)、(1.13)得Z3=18.78,Z4=26.64, 取整Z3=19,Z4=27
??则: i4 =
Z2Z3 Z1Z433?19
12?27 =1.93≈i4=1.56 对四挡齿轮进行角度变位: 理论中心距 Ao?mn?Z3?Z4?=99.23mm
2cos?3?4端面压力角 tan?t=tan?n/cos?3?4=0.393 ?t=21.43° 端面啮合角 cos?t,?Ao99.23cos?t=cos21.43?=0.939 A98 ?t,?20.15?
?,?z3?z4??inv??inv??tt???变位系数之和 ?n?? =-0.302
?2tan?n?
?3=0.01 ?4=-0.302-0.01=-0.312
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求螺旋角?4的精确值:A?四挡齿轮参数:
mn?Z3?Z4? ?3?4=20.15°
2cos?3?4分度圆直径 d3?z3mn=80.95mm
cos?3?4z4mn=115.04mm
cos?3?4 d4?齿顶高 ha3??h?an??3??yn?mn=6.556mm ha4??h?an??4??yn?mn=5.268mm
(A?A0)/mn=-0.307 式中:yn? ?yn??n??yn=-0.629 齿根高 hf3?h?an?cn??3mn=4.96mm hf4?an???h??cn?????m=6.248mm
4n齿全高 h?ha3?hf3=11.51mm 齿顶圆直径 da3?d3?2ha3=94.062mm da4?d4?2ha4=127.536mm 齿根圆直径 df3?d3?2hf3=71.03mm df4?d4?2hf4=102.54mm 当量齿数 zv3?z3/cos3?3?4=22.97 zv4?z4/cos3?3?4=32.65
??2A节圆直径 d3z319?2?98??80.96mm
z3?z419?27 r3??1??40.48mm d32z427?2?98??115.04mm
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r4??
5、确定倒挡齿轮齿数
1??57.52mm d42倒挡齿轮选用的模数与一挡相同,倒挡齿轮Z13的齿数一般在21~23之间,初选Z12后,可计算出中间轴与倒挡轴的中心距A,。初选Z13=23,Z12=14,则:
A,?1m?Z12?Z13? 21=?4??14?23? 2=74mm
为保证倒挡齿轮的啮合和不产生运动干涉,齿轮12和11的齿顶圆之间应保持有0.5mm以上的间隙,则齿轮11的齿顶圆直径De11应为
De12D?0.5?e11?A 22 De11?2A?De12?1 =2×98-4×(14+2)-1
=131mm
Z11? =
De11?2 m131-2 4=30.75
为了保证齿轮10和11的齿顶圆之间应保持有0.5mm以上的间隙,取Z11=30
计算倒挡轴和第二轴的中心距A??
A,,?m?z13?z11? 2Word文档
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4??23?30?
2 =106mm 计算倒挡传动比
i倒? =
z2z13z11 ??z1z12z1331?23?30
14?14?23=4.74
倒挡齿轮参数:
u12?13?z13?1.64,查表得?12?0.24,?13??0.24z12z11?1.30,查表得?13??0.24,?11?0.24 z13
u13?11?分度圆直径 d11?z11m=30×4=120 mm d12?z12m?14×4=56 mm d13?z13m?23×4=92 mm
齿顶高 ha11??h*a??11?m?4.96 mm ha12??h*a??12?m= 4.96 mm ha13??h*a??13?m =3.04 mm
?齿根高 hf11?h?a?c??11m=4.04 mm ? hf12?h??c??12m=4.04 mm a?hf13??h?a?c??13?m=5.96 mm
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齿全高 h?ha11?hf11=9 mm 齿顶圆直径 da11?d11?2ha11=129.92mm da12?d12?2ha12=65.92mm
da13?d13?2ha13=98.08mm
齿根圆直径 df11?d11?2hf11 =111.92 mm df12?df12?2hf12=47.92 mm df13?df13?2hf13=80.08 mm
??2A??节圆直径 d11z1130?2?106??120mm
z11?z1330?23?? r111??60mm d112z1214?2?74??56mm
z12?z1314?23??2A? d12?? r121??28mm d122z1323?2?106??92mm
z11?z1330?23??2A??d13?? r13
1??46mm d1321.4 本章小结
本章首先根据所学汽车理论的知识计算出主减速器的传动比,然后计算出变速器的各挡传动比;接着确定齿轮的参数,如齿轮的模数、压力角、螺旋角、齿宽、齿顶高系数;介绍了齿轮变位系数的选择原则,并根据各挡传动比计算各挡齿轮的齿数,根据齿数重新计算各挡传动比,同时对各挡齿轮进行变位。
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汽车设计变速器设计说明书



