The function of the engine valve train group
The function of the valve train group is to make the intake and exhaust valves open and close at the time specified by the valve timing phase, and to ensure that they have sufficient opening. Spend. The valve drive group is all the parts starting from the timing gear to pushing the valve action. Its composition varies depending on the form of the valve mechanism. The valve drive group mainly includes the camshaft, timing gear, tappets and their guide rods. Rods, rocker arms and rocker shafts, etc.
Engine valve transmission group composition
1. Camshaft
The camshaft is a key component of the valvetrain, which controls the valve timing. Some engines are also used to drive oil pumps, gasoline pumps and distributors. The camshaft is mainly composed of intake and exhaust cams, support shafts, timing gear shafts, gasoline pump eccentric cams, oil pumps and distributor drive gears.
2. Valve lifter
The function of the lifter is to transmit the thrust of the cam to the push rod (or valve stem) and withstand the lateral force exerted during rotation. For side-valve-mounted valve mechanisms, the tappets are generally made into a mushroom type, and an adjusting screw is installed on the top of the tappets to adjust the valve clearance. The tappets of overhead-valve valve trains are generally made into cylinders to reduce weight.
3. Valve top cup
(1) Some components for adjusting valve clearance are eliminated, greatly simplifying the structure.
(2) The valve clearance can be automatically compensated, which brings convenience to assembly, use and maintenance, saving labor and time.
(3) The noise, impact, etc. caused by the valve clearance are eliminated, and the friction and wear of the cam profile and the top surface of the tappet are reduced.
4. Valve rocker arm and rocker arm shaft
It is actually a two-arm lever, used to change the direction of the force from the push rod and act on the valve rod end to push Open the valve. The ratio of the arm lengths on both sides of the rocker arm 7 (called the rocker arm ratio) is about 1.2 to 1.8, in which one end of the long arm pushes the valve.
5. Camshaft timing gear
The timing gear is a gear in the mechanical device that plays a time-scale positioning role in completing relevant control functions. Timing gears have been introduced into local systems that have a sequential relationship with the completion of mechanical functions, such as the intake and exhaust systems in internal combustion engines and clocks. It can play a time-scale positioning role in completing relevant control functions in mechanical devices.
6. Valve pushrod
The function of the pushrod is to transfer the thrust from the cam wheel through the tappet to the rocker. It is the most flexible part in the valve mechanism. . High stiffness is required. In engines with large dynamic loads, the push rods should be made as short as possible. For cylinderFor engines where the cylinder head and cylinder head are made of aluminum alloy, the push rods are best made of hard aluminum.
If the website content violates your rights, please contact us to delete it。
