Chainsaws are garden tools powered by gasoline engines and mainly used for logging and lumbering. 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, which directly determines the function and service life of the chain saw. The body of the chain saw engine mainly includes a cylinder, a piston, a connecting rod, a crankcase, and Flywheel, etc. Let's take a look at these important chainsaw accessories that make up the chain saw engine body.

1. Cylinder

The cylinder is a cylinder in which the piston moves, and it is the place for the combustion and explosion of the mixture. 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 cylinders are mostly 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, so the upper part of the cylinder is more worn than the lower part. At the same time, when the connecting rod moves in the cylinder, it swings left and right, and the wear degree on the left and right sides is large. After grinding to a certain extent, the cylinder of the chain saw engine should be replaced.

2. Piston

The piston is subjected to the pressure of the working gas of the chain saw engine, reciprocates, 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 of the piston engine is mostly arc-shaped at the top. With the flow of the mixture, the temperature of the upper part of the piston is relatively high, so the diameter of the upper part is smaller than that of the lower part during manufacture, which is used as the expansion flow. In order to ensure the tight combination 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 rotational motion of the crankshaft. The small end of the connecting rod is connected with the piston, and the large end is connected with the crankshaft.

4. Crankshaft

The crankshaft converts the linear motion of the pistons to rotational motion with the help of cylinders, pistons and connecting rods. At the same time, it can push the piston to make a reciprocating linear motion. 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 to form the crankshaft. The crankshaft is generally installed in the crankcase with the help of ball bearings.

5. Flywheel

The basic function of the flywheel is to maintain the balance of engine operation. In addition to that, the flywheel makes the engine easy to start. When the explosion stroke begins, the rotational energy of the crankshaft is stored, and before the piston passes through ignition, top dead center, and the mixture compression reaches the maximum, the flywheel releases the energy, so that the crankshaft continues to rotate.

6. Crankcase and flywheel housing

The crankcase is the base of the engine, on which the components and parts of the engine are installed, such as cylinders, ignition devices, etc. The crankcase of the two-stroke chain saw engine also functions as a scavenging pump in addition to the rotating parts of the engine to rotate in it. In order to maintain a certain pressure in the body and prevent the mixed fuel or gas in the body from running out, an oil seal is provided between the crankshaft and the crankcase. There is a flywheel housing on the outside of the flywheel, which plays a protective role. The outer side of the flywheel housing has a helical conduit, which is a part of the cooling system of the chain saw engine. Therefore, the flywheel housing is also the housing of the blower.