Crankshaft crank throw curved forging mould for large ship and designing method of preformed blank

Abstract

The invention relates to marine type crankshaft bell crank bending swaging dies and preliminary shaping blank design method. It uses computer modeling technique to design preliminary shaping blank, V shape die, bend upper and lower dies, lower cavity die, plug board, and various die matching using methods. The method can save raw materials, shorten production cycle, and reduce admittance. The designed die and preliminary shaping blank can generate total models crankshaft bell crank parts which have good forming quality, symmetrical appearance, uniform flow line and admittance for MANB&, W and WNSD diesel engine patent company.

Description

technical field [0001] The invention belongs to the field of forging, and specifically relates to a design method of a bending forging die and a preformed blank of a crank throw for a ship, which is suitable for the process of the mold and the preformed blank of a large crank throw for a ship. Background technique [0002] The crankshaft is the most important part of a diesel engine. The value of the crankshaft of a large-scale marine diesel engine accounts for about 10-15% of the value of the whole machine. At present, the annual demand in my country is more than 200 pieces, and most of the crankshafts are imported from Japan, South Korea and other countries. The crankshaft is not only expensive, but also the delivery is not timely. The matching of the crankshaft has become a bottleneck problem restricting the development of my country's shipbuilding industry. [0003] The common large-scale low-speed diesel engine crankshaft (single crank weight is more than 5 tons, and the...

AI Technical Summary

Problems solved by technology

[0005] In the bending and forming process of the crank throw in the existing technology, defects such as bell mouth and folding cracks are prone to occur in the opening of the crank throw, and defects such as thinning and waist shrinkage are prone to appear on the side of the crank arm, which will cause the crank throw forging to be scrapped in severe cases

Most of the formed forgings are in the shape of a cuboid, and the machining allowance is uneven, especially at the position of the crank pin. The cross-section of the processed parts is circular, but the actual forgings are all rectangular. The first method is to use gas cutting to remove the excess material on the crank pin. This method has the advantages of fast speed and high efficiency. The disadvantage is that the gas cutting operation is difficult, there is a heat-affected zone, and waste products are easily produced; the other method is to use the bell crank Vertical lathe processing, this method has the advantage of high yield, but large processing allowance and long processing time

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