refers to a link bolt and the screw fastener head of the bolt connected together, with the need to use with the nut.
1. The connecting rod bolt defined
we use the connecting rod bolt, connecting rod bolt and some find many problems, there is the appearance of the problem, the length tolerance problems, fracture, dental thread problem, the problem found when mounting the like. Where
a very simple way, that is, the connecting rod bolt inspection, identify problems in order to change it. That need for testing methods rod bolt, connecting rod bolt is bolted important big end bearing cap and the bearing housing so as to integrally. Rod bolt action by the preload during assembly, when the four-stroke diesel engine running rod bolt further subjected to reciprocating inertia force. A small diameter rod bolt, is limited because of its big end of the crank pin and an outer diameter dimension of the gallery.
2. The connecting rod bolt Introduction
the link with the split cover fixed to the connecting rod bolts. In every sub-bearing, generally with two or four connecting rod bolt fastening. This type of bolt is mixed. Often machined with its head positioned in a plane or bumps, so that when it is mounted with a bearing surface fitted to prevent the rotation of rod bolt during tightening the nut. Located at the split face of each bearing bolt shank having a larger diameter, so as to be positioned with the bolt hole assembly; the remaining diameter of the bolt shank portion is smaller than the diameter of the bolt holes, and longer length, so as to withstand bending and impact reduce the load when the load of the threaded portion. A threaded portion often used fine threads high accuracy.
In order to prevent spontaneous loosening a threaded connection, there is a permanent rod bolt locking means, usually a split pin, the locking washer and threaded surface plating of copper. Rod bolts often alternating loads, tend to cause fatigue fracture and breakage, will cause extremely serious consequences. Thus, it is often made of high quality steel or high carbon steel, heat treatment and after quenching. Management, which fastening should check the situation, to prevent loosening; its periodic disassembly inspection for cracks and the like over-elongation, should the need for timely renewed. When installed, to cross gradually according to a predetermined preload tight, not too large or too small, so the work of connecting rod bolt caused problems such as rupture.
3. Bolt link Note
In order to prevent the connecting rod bolt deformed or broken due to improper installation, the installation should note the following:
(1) before installation, cleaning and careful visual inspection, and inspection with a bolt and nuts, should be no jamming and loosening.
(2) the size of the bolts and the preload method shall be as specified diesel specification. Because too large or too small preload, uneven preload bolts etc. can not guarantee reliability of its work.
(3) the maintenance can not freely exchange relationship therewith original rod bolt fitting hole, since the connecting rod bolt holes are fitted with a transition fit, and gently knock required hammer bolt, freely exchange relationship with the impact, over tight, too loose all affect the reliable operation of the connecting rod bolts.
4. Faulty rod bolt
① twist assembly tightening torque is too large, uneven force. Since there is no strict assembly equipped with the torque wrench, the tightening torque and particularly not know that tight as possible; a fastening bolt with a longer connecting rod urging rod tightening torque is too large, than the material of the bolt yield limit, the link bolt yield deformation occurs, so that due to excessive elongation of break under an impact load. It should be emphasized that, according to a certain standard tightening rod bolts, do not think that the more tight, force the bigger the better.
② diesel multiple levels of sub-link, in the repair should be noted not change with different levels of link. If for sloppy careful not to confuse the connecting rod cap in the overhaul, the wrong equipmentWill cause the connecting rod is not tightly bound with the surface, during engine operation will cause the connecting rod cap loose and cause breakage of the connecting rod bolt.
③ diesel engine or piston Runaway occurs burned in the cylinder failure in operation, pull off the connecting rod bolt. If the engine failure occurred coaster in use, the engine response to do a comprehensive inspection, it is best to replace the connecting rod bolts; if the individual cylinders in operation there have been more serious pull-cylinder, replace the cylinder when the piston rod assembly should also be bolt replacement.
④ material issues, manufacturing defects can also cause problems and heat treatment process rod bolt to fracture during engine operation.