Ball and lead screws are specified by the diameter of the screw shaft and the lead (or, in some cases,pitch) of the screw thread. The lead, which specifies how far the nut travels for each revolution of the screw, is created by the thread, or helix, that wraps around the screw shaft.
如果螺旋从螺钉上“打开”，则可以使用螺钉的圆周和引线，形成右三角形。螺旋用作三角形的斜边，圆周和铅构成另外两侧。
In this triangle, the angle made up by the screw circumference and the helix is known as the lead angle (B). The angle formed by the lead and the helix is known as the helix angle (A). The lead angle and helix angles are complementary (their sum must equal 90 degrees), so if the lead angle gets larger, the helix angle will get smaller.
图像信用：tools-n-gizmos.com
不te that some reference materials refer to the angle (B), between the screw circumference and the helix, as the helix angle. When the term “helix angle” is used, be sure to look for a definition or diagram to confirm which angle is being referenced.
A high helix screw is generally recognized as one whose lead (P) is equal to or larger than the screw diameter (d0).
图片信用：Eichenberger Gewinde
高螺旋螺钉的示例是20 x 20,6 x 25和40 x 80的尺寸，并且一些高螺旋设计具有螺杆直径的六倍的引线。铅越大，线性行驶速度越快。因此，高螺旋螺丝最大化线性行进速度，同时保持直径，质量和螺钉的惯性。通过保持旋转速度低，减少可听噪声和振动。
Because the lead of a high helix screw is large — that is, the helix that wraps around the screw is “stretched out” — there are fewer effective turns of balls (in the case of a ball screw) or less screw-nut contact (in the case of a lead screw) to support the load. To counter this situation, some manufacturers add additionalball tracks, or turns螺杆轴 - 通常称为多启动螺钉的设计。对于滚珠丝杠，添加转弯或轨道，增加可用负载的球的数量。对于铅螺钉，添加转弯增加了可用负荷的接触区域的量 - 但它也增加了摩擦和热量，这会影响PV valueof the screw.
与高螺旋或高铅，螺钉的相反是一个细间距或细小铅螺钉。细螺距螺钉通常定义为具有小于螺杆直径的一半的引线的细，例如16×5或12×2尺寸。通常在需要非常小的移动时使用细螺距螺钉。
Filed Under:线性运动Tips
