【名词&注释】
控制阀(control valve)、差速器壳(differential carrier)、排气阀门(air evacuation valve)、锥齿轮差速器(bevel gear differential)
[单选题]设对称式锥齿轮差速器(bevel gear differential)壳的转速为no,左、右两侧半轴齿轮的转速分别为nl和n2,则有()
A. A.nl+n2=no
B. B.nl+n2=2no
C. C.nl+n2=1/2no
D. D.nl=n2=no