SAE花键标准简介
ANSI B92.1-1970 SAE花键标准
INVOLUTE SPLINES
渐开线花键
Form Circle is the circle which defines the deepest points of involute form control of the tooth profile. This circle along with the tooth tip circle (or start of chamfer circle) determines the limits of tooth profile requiring control. It is located near the major circle on the internal spline and near the minor circle on the external spline.
渐开线终止圆：渐开线终止圆是用于操纵齿廓上渐开线的极限距离的圆。渐开线终止圆与齿顶圆（或者修缘线的起点所在的圆）共同限制了所要求操纵的渐开线齿廓的范围。渐开线终止圆的位置靠近内花键的大圆（齿根圆）或者外花键的小圆（齿根圆）。译者注：这段话的意思是：只有在渐开线终止圆与齿顶圆（或者修缘线的起点所在的圆）之间的花键的齿形为渐开线齿形，其余部分不一定按照渐开线成形。
译者注2：在《GB/T 3478.1-1995 圆柱直齿渐开线花键》中，将Form Cycle定义为两个圆：内花键的渐开线终止圆和外花键的渐开线起始圆。而在本标准中，将这两个圆统称为Form Cycle，译者将Form Cycle翻译为渐开线终止圆。
Form Clearance (c F) is the radial depth of involute profile beyond the depth of engagement with the mating part. It allows for looseness between mating splines and for eccentricities between the minor circle (internal), the major circle (external), and their respective pitch circles.
齿形裕度：齿形裕度（c F）是相互配合的内、外花键的渐开线齿廓在径向方向上的间隙。齿形裕度是的相互配合的内、外花键之间能够存在一定松动，同时是的内花键的小圆（齿顶圆）、外花键的大圆（齿顶圆）、以及内、外花键各自的节圆之间存在一定的偏心距。
Form Diameter (D Fe, D Fi) the diameter of the form circle. 渐开线终止圆直径（D Fe, D Fi）：渐开线终止圆所在圆的直径。
Internal Spline is a spline formed on the inner surface of a cylinder.
内花键：在圆柱体的孔的内表面形成的花键。
Involute Spline is one having teeth with involute profiles. 渐开线花键：花键的键齿的齿形为渐开线形式的花键。
Lead Variation is the variation of the direction of the spline tooth from its intended direction parallel to the reference axis, also including parallelism and alignment variations (see Fig. 1a). Note: Straight (nonhelical) splines have an infinite lead.
导向公差：导向公差是花键的键齿的实际齿线与花键的参考轴线之间的平行度公差，那个公差包括平行度公差和圆周阵列公差（见图Fig.1a）。注意：直齿花键（非螺旋花键）的导向公差为无穷大。
译者注：这一条解释有待斟酌。
Length of Engagement (L q) is the axial length of contact between mating splines.
结合长度（L q）：结合长度是两个相互配合的内、外花键之间的接触段的长度。
Machining Tolerance (m) is the permissible variation in actual space width or actual tooth thickness.
加工公差（m）：加工公差是花键的实际齿槽宽和实际齿厚的同意的变动量。
译者注：在《GB/T 3478.1-1995 圆柱直齿渐开线花键》中，将加工公差定义为T。
Major Circle is the circle formed by the outermost surface of the spline. It is the outside circle (tooth tip circle) of the external spline or the root circle of the internal spline.
大圆：大圆是花键的最大齿形面的包络圆。它是外花键的外圆（齿顶圆），和内花键的齿根圆。
Major Diameter (D o, D ri) is the diameter of the major circle. 大圆直径：大圆直径（D o, D ri）是大圆所在圆的直径。
译者注：在《GB/T 3478.1-1995 圆柱直齿渐开线花键》中，将大圆直径定义为：内花键D ei、外花键D ee。
Minor Circle is the circle formed by the innermost surface of the spline. It is the root circle of the external spline or the inside circle (tooth tip circle) of the internal spline.
小圆：小圆是花键的最小齿形面的排斥圆。它是外花键的齿根圆，和内花键的内圆（齿顶圆）。
Minor Diameter (D re, D i) is the diameter of the minor circle. 小圆直径：小圆直径（D re, D i）是小圆所在圆的直径。
译者注：在《GB/T 3478.1-1995 圆柱直齿渐开线花键》中，将小圆直径定义为：内花键D ii、外花键D ie。
Nominal Clearance is the actual space width of an internal spline minus the actual tooth thickness of the mating
external spline. It does not define the fit between mating members, because of the effect of variations.
理论侧隙：理论侧隙是内花键的实际齿槽宽减去与之相互配合的外花键的实际齿厚所得的值。由于内、外花键在配合时会产生一定的公差，因此理论侧隙不能够用于确定相互配合的内、外花键之间的间隙。
Out of Roundness is the variation of the spline from a true circular configuration.
圆度：圆度是花键与真圆的圆廓之间的公差。
Parallelism Variation is the variation of parallelism of a single spline tooth with respect to any other single spline tooth (see Fig. 1b).
平行度公差：平行度公差是单根键齿相对其它的单根键齿之间的平行度公差。（见图Fig.1b）
Pitch (P/P s) is a combination number of a one-to-two ratio indicating the spline proportions; the upper or first