Important parts of chain saw engine block
Chainsaws are powered by gasoline engines and are mainly used as garden tools for logging and timber production. The power part of the chain saw is a gasoline engine. The body of the chain saw engine is the main part of generating power. It directly determines the functional power and service life of the chain saw. Flywheel and other components. Let's take a look at these important chain saw accessories that constitute the body of the chain saw engine. 1. Cylinder The cylinder is a cylinder for the piston to move in, and it is a place for the combustion of the mixture to explode. In order to increase the wear resistance of the inner wall of the cylinder and increase the heat dissipation of the cylinder, the chain saw cylinder is mostly made of aluminum alloy castings, and the inner wall is chrome plated. The upper part of the cylinder is the main work place of the chain saw engine. Therefore, the upper part of the cylinder wears more than the lower part. At the same time, the connecting rod swings left and right when moving in the cylinder, and the degree of wear on both the left and right sides is large. After grinding to a certain degree, the cylinder of the chain saw engine should be replaced. Second, the piston The piston bears the pressure of the working gas of the chain saw engine, makes a reciprocating motion, and transmits the pressure to the crankshaft mechanism through the connecting rod. At the same time, it is driven by the connecting rod and crankshaft (by inertial force) to complete the intake, compression and exhaust work. The piston crown of a piston engine is mostly arc-shaped, and the temperature of the upper part of the piston is higher due to the flow of the mixed gas. Therefore, the diameter of the upper part is smaller than the diameter of the lower part during manufacture, which is used as the expansion flow rate. In order to ensure the tight connection between the piston and the cylinder wall and ensure good compression, there are 2-4 piston rings in the ring groove on the piston, and the opening gap is 0.10-0.15mm, which is used as the expansion flow. 3. Connecting rod The connecting rod is used to connect the piston and the crankshaft of the engine, transmit the gas pressure received by the piston to the crankshaft, and change the reciprocating linear motion of the piston into the rotary motion of the crankshaft. The small end of the connecting rod is connected with the piston, and the big end is connected with the crankshaft. 4. Crankshaft The crankshaft uses the cylinder, piston and connecting rod to change the linear motion of the piston to rotational motion. At the same time, it can push the piston and make it reciprocate linearly. In order to simplify the manufacture of the crankshaft, the crankshaft of the chain saw engine is composed of two half shafts, two crank arms and a crank pin. The end of the half shaft and the crank pin are pressed into the crank arm, and finally connected into the crank shaft. The crankshaft is usually installed in the crankcase by means of ball bearings. Five, flywheel The basic function of the flywheel is to maintain a balanced engine operation. In addition, the flywheel can make the engine easy to start. When the burst stroke begins, the rotational energy of the crankshaft is stored. Before the piston reaches the maximum through ignition, top dead center, and gas mixture compression, the flywheel releases the energy and causes the crankshaft to continue to rotate. 6. Crankcase and flywheel housing The crankcase is the base of the engine, on which are mounted engine components and parts, such as cylinders, ignition devices, etc. The crankcase of a two-stroke chain saw engine, in addition to allowing the rotating parts of the engine to rotate in it, also functions as a scavenging pump. In order to maintain a certain pressure in the machine body and avoid mixed fuel or gas in the machine body, an oil seal is provided between the crankshaft and the crankcase. There is a flywheel housing on the outside of the flywheel for protection. The outside of the flywheel housing has a spiral duct, which is part of the cooling system of the chain saw engine. Therefore, the flywheel housing is also the housing of the blower.