The camshaft is an important part of the engine. Accord […]
The camshaft is an important part of the engine. According to the number of camshafts, it can be divided into single overhead camshaft and double overhead camshaft. So what role do they play in the car engine? Next, I will sort out some of the functions of the camshaft of the car in the auto parts.
single overhead camshaft
The single overhead camshaft uses a cam shaft on the cylinder head to directly drive the intake and exhaust valves. It has a simple structure and is suitable for high-speed engines. The side camshaft generally used in the past, that is, the camshaft is on the side of the cylinder, is directly driven by the timing gear. In order to convert the rotation of the camshaft into the reciprocating motion of the valve, a valve lifter must be used to transmit power. In this way, there are many parts in reciprocating motion, and the inertial mass is large, which is not conducive to the high-speed motion of the engine. Moreover, the slender tappet has a certain elasticity, which is easy to cause vibration, accelerate the wear of parts, and even make the valve out of control.
double overhead camshaft
Overhead twin camshafts are two camshafts mounted on the cylinder head, one for driving the intake valve and the other for driving the exhaust valve. The use of double overhead camshafts does not require high design requirements for camshafts and valve springs. It is especially suitable for hemispherical combustion chambers with V-shaped valves, and is also easy to use with four-valve valve trains.
To put it simply, the camshaft of a car is to make the intake and exhaust of the valve of each cylinder of the engine work, and it is an indispensable component in the car parts.
The body of the camshaft is a cylindrical rod approximately the same length as the cylinder bank. There are several cams on it, which are used to drive the valves. The camshaft is supported in the camshaft bearing hole through the camshaft journal, so the number of camshaft journals is an important factor affecting the rigidity of the camshaft support. If the rigidity of the camshaft is insufficient, it will bend and deform during operation, which will affect the timing of gas distribution.
The sides of the cam are egg-shaped. The purpose of its design is to ensure sufficient intake and exhaust of the cylinder. In addition, considering the durability of the engine and the smoothness of operation, the valve should not have too much impact due to the acceleration and deceleration process during the opening and closing actions, otherwise it will cause serious valve wear, increased noise or other serious consequences. Therefore, there is a direct relationship between the cam and the engine's power, torque output, and smoothness of operation. Common transmission methods between the camshaft and the crankshaft include gear transmission, chain transmission and toothed belt transmission. The transmission between the lower camshaft and the middle camshaft and the crankshaft is mostly driven by cylindrical timing gears. Generally, only one pair of gears is needed to drive from the crankshaft to the camshaft. If the diameter of the transmission gear is too large, an additional intermediate gear can be added. Idler. In order to mesh smoothly and reduce working noise, the timing gears are mostly helical gears.
The chain drive is commonly used between the overhead camshaft and the crankshaft, but its working reliability and durability are not as good as the gear drive. Toothed tapes are widely used instead of drive chains on high-revving engines, but chain drives are still used on some high-power engines. Toothed tape has the characteristics of low noise, reliable operation and low cost. For DOHC, generally the exhaust camshaft is driven by the crankshaft through a timing toothed belt or chain, the intake camshaft is driven by the exhaust camshaft through a metal chain, or both the intake camshaft and the exhaust camshaft are driven by the crankshaft. Driven by the crankshaft via toothed belts or chains.
Zhejiang Junrong Auto Parts Co., Ltd. is a professional enterprise engaged in the research, development, production and sales of automotive camshafts. As 4-cylinder dual VVT camshaft Manufacturers and 4-cylinder single VVT overhead camshaft Suppliers, it has become a major supporting supplier for well-known automobile brand manufacturers such as Shanghai Automobile, Geely and Zotye.The company transportation is very convenient which occupies an area of 40 mu, with complete supporting facilities, a standard factory building of 4-cylinder single overhead camshaft more than 20,000 square meters.