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There are many design methods for the cross-rolled steel ball hole type. The following methods are commonly used:
(1) One-side variable lead method for the hole type convex rib: The one-sided variable lead method for the hole type convex rib is also called the cylindrical roll hole type design method, which is established. The method of designing and processing on a cylindrical roll blank is a method of hot rolling steel balls designed by the former Soviet Union. Since the roll hole type can be processed on a conventional lathe, it is a basic method widely used at present. It is not only suitable for steel balls, rollers, etc. with simple shapes, but also for shaped parts with complex shapes, such as q-7 ball head, h-1 step shaft, etc. Its hole characteristics are: 1) single side variable lead, the other side is the basic lead. The left side lead t of the rib is a function of the hole type expansion angle, and the right side lead is a constant basic lead t; 2) the rib width is narrowed and widened. The width of the rib is widened from the inlet to the discharge opening. In the first ring and the finishing zone where the hole is not closed, the width of the rib of the hole type can be constant; 3) the roll manufacturing is easier It can be processed on the ordinary lathe by changing the hanging wheel, so the requirements for the manufacturing equipment are not high, and the geometric precision of the ball is not high enough.
(2) Hole type double-sided synchronous variable lead method: The hole type double-sided variable lead method is also called the tapered roll hole type design method, and the rib height is naturally formed on the tapered roller surface, and the hole type design and The processing is based on the tapered roll blank, and the lead on both sides of the rib is changed. It is designed for rolling small diameter bicycle balls in the United States. It is currently used to design cold-rolled steel balls with a diameter of 3 to 6.5 mm. The starting point for the two-sided variable lead design method is to simplify the hole patterning. However, the top of the rib is a slope, and the equation is established according to the volume balance condition to obtain the ridge width, the spiral lead, etc. The change law is not a simple linear relationship, and the calculation is not only complicated, but also the machining accuracy is difficult to guarantee. In view of the fact that the roll taper angle and the rib width are not large, the ridge top can be regarded as straight and the calculation error is very small, so that the design and manufacture are much simpler.