Crankshaft is one of the main elements of the engine. It is part of the crank mechanism. It has a complex device. What is this mechanism? Let's consider.
Device and purpose
The crankshaft senses the forces from the piston and converts them into mechanical energy. This mechanism is affected by the forces of rotation. He works constantly under a high load. Therefore, in order to prevent the premature failure of the component, the crankshafts are made of high-quality, high-strength cast-iron alloys. Then all parts are hardened by high frequency current. Distinguish the shafts with a double counterweight or even without a counterweight. The engine is mounted directly in the motor housing. As for the design, it generally depends on the engine. Despite some differences, there are a lot in common in the constructions. Crankshaft is a complex of several parts. As a support for this design, the neck is used - more often there are models with four necks, but there are also three-bearing ones. In the six-cylinder motors shafts are installed where such supports are used. 7. In order for the crankshaft to be balanced, counterweights are used. If the cylinders have a small diameter, then use a single counterweight. Due to these details, the maximum smooth operation of the power unit is ensured.
Auxiliary mechanisms
So, knowing what the engine crankshaft is designed for and what forces act on it during operation, one can understand why the mating between the cheeks and the connecting rod neck is slightly rounded. This helps prevent premature failure. Between the cheeks there is a connecting rod. The mechanics that serve the engines call it the "knee". It is designed to ensure uniform ignition, so that the engine is as balanced as possible, so that the minimum torsional and bending forces act on the shaft. Crankshaft is a part that operates at high revs. The rotation of the connecting rods and the shaft itself on the supports is provided by sliding bearings. The thrust elements on the extreme or middle root neck are established. The tasks of this bearing include preventing axial displacements and moving the mechanism. If we take into account how many details should be coordinated and clearly operate in one mechanism, it is not difficult to say that during production the crankshaft is carefully balanced. But sometimes you can find unbalanced details. In the sale of such products do not arrive.
Crankshaft operation from the inside
The principle of operation is simple in general. When the piston is maximally removed, the jaws and crankshaft cranks are aligned in one line. At this point in the combustion chambers ignites fuel and emits gases that move the piston to the crankshaft. The piston also moves with the piston, the head of which cranks the crankshaft. When the latter turns around, the connecting rod neck moves upward and the piston moves with it.
Lubrication system
An important role is played by lubrication. Crankshaft is a detail of rotation, which means that it will experience friction. A lubricant supply is provided from the common lubrication line to the neck supports. Then, through the canals in the cheeks, oil will fall on the necks of the connecting rods. Lubrication significantly increases the wear resistance of all shaft parts.
Malfunctions
Due to high loads, this mechanism fails. Among typical faults, accelerated wear of the necks can be identified. It is associated with problems in the cylinder block. Also often there are scuffles on the surfaces of necks. This happens due to unsatisfactory circulation or lack of lubrication, or due to a violation of temperature conditions. Scratches on the surfaces of the necks can be seen especially often. It is necessary to distinguish simply scratches and cracks, which are formed due to metal fatigue. Often there are beats and deflection of the details. This is especially true for high-revving vehicle engines. Another typical failure is the deviation of the necks from their factory size. But this is a more natural process than all the others. It should be taken into account that the crankshaft dimensions have a tolerance of no more than 0.02 millimeters. Any mismatch is eliminated by grooving on specialized equipment.
How do I replace?
Of course, with some types of malfunctions, you can do repair - polishing or grooving. But sometimes it is not possible to restore the shaft. In this case, you can replace the old mechanism with a new one. By the way, in the engine this is the most expensive component. Especially in diesel power units. Before the crankshaft is replaced, axial play is checked. This will simplify the selection of axle liners. It is necessary to find labels on the liner and the cylinder block. They indicate the direction of installation of the main bearing caps. All parts that interfere with the dismantling of the shaft must also be removed. In the repair manuals, the dismantling process is described in different ways, as there are 8 and 16-valve engines, with a row or V-shaped cylinder arrangement. Then you need to install a new crankshaft in place of the old one - you must strictly follow the instructions of the car manufacturer and do not mistake the position of the crankshaft. In view of the high responsibility, all work needs to be done in a specialized service.
So, we found out the device, purpose and principle of the crankshaft car.