滚动轴承内圈或外圈旋转时的缺陷频率

zhiwenty

为什么好多人都说不管是内圈固定外圈旋转，或内圈旋转外圈固定，轴承内外圈的缺陷频率是一样的，但公式不一样啊，算出来的肯定不一样啊，
内圈旋转，外圈固定
FTF = (Hz/2)[1-(B/P)cosCA]
BPFO = (N/2)Hz[1-(B/P)cosCA]
BPFI = (N/2)Hz[1+(B/P)cosCA]
BSF = (PHz/2B){1-[(B/P)cosCA]2}
Where:
Hz. = rotor speed in cps
N = number of rolling elements
B = ball diameter
P = pitch diameter
CA = contact angle

内圈固定，外圈旋转
FTF = (Hz/2)[1+(B/P)cosCA]
BPFO = (N/2)Hz[1+(B/P)cosCA]
BPFI = (N/2)Hz[1-(B/P)cosCA]
BSF = (PHz/2B){1-[(B/P)cosCA]2}
Where:
Hz. = rotor speed in cps
N = number of rolling elements
B = ball diameter
P = pitch diameter
CA = contact angle

sunrain

马上要做球轴承，不懂，过来学习下哈！
怎么没人回答呢？