Timing belts are used for power transmission or to interchange linear motion and rotary motion where maintaining a specific drive ratio or high loads are important. They are most widely used in the regulation of internal combustion engine operation. Linear position systems are a common non-automotive application of timing belts.
In the context of internal combustion engines, timing belts are the component responsible for controlling the timing of an engine’s valves. If tensioned properly, timing belts have no slippage and are used to transfer direct motion for timing or indexing purposes. Timing belts are utilized in the camshafts of automobiles and stepper motors.
They began to replace engine timing chains in 1970s. One of the advantages of timing belts over timing chains and gears is that timing belts do not require lubrication. They are specially designed to precisely fit around the gears with which they operate. Their use helps to ensure the safe and efficient operation of important engine components. Though in recent years there has been a moderate resurgence of timing chains and other non-belting engine regulation components, timing belts continue to be the dominant utility for engine valve regulation.
In automotive applications, a timing belt is a reinforced rubber belt with square teeth driven by the crankshaft, which operates the camshaft. In some engine designs, timing belts are also used to drive other engine components such as the water pump and oil pump. Compared to a gear or chain system, rubber timing belts are more cost effective, quieter in their operation, and mechanically more efficient.
Rubber timing belts can be made out of several different materials. Traditionally, rubber belts have been made out of natural rubber and integrated synthetic fibers for added strength. Natural rubber is not very heat resistant, though, and it can corrode in the presence of oil and other petrochemicals. For this reason, synthetic rubber materials like highly-saturated nitrile and other varieties have gained in popularity.
Conveyor belt materials can be engineered to resist high heat and corrosion, which gives them a longer operating lifespan than natural rubber belts. Because of their importance in so many engine systems, timing belts are widely manufactured and are likely to continue to occupy a large percentage of all conveyor belt varieties produced annually.
Timing Belts Informational Video