Nylon Sprocket

Definition and Function

A sprocket is a wheel with embedded chain – engaging teeth, used to mesh with accurately – pitched blocks on a link chain or cable. It is mainly used to transmit power and motion in mechanical transmissions.

Structural Design

Tooth Profile
The commonly used end – face tooth profile of a sprocket is a three – arc – straight – line tooth profile composed of three arcs and one straight line. This tooth profile can ensure that the chain links can smoothly enter and exit the meshing, reducing the impact and contact stress of the chain links during meshing, and it is easy to machine.
Structure
Small – diameter sprockets are generally made as an integral type. Medium – diameter sprockets are mostly of the spoke – plate type, and holes can be made on the spoke – plate to reduce weight and facilitate handling and clamping. Large – diameter sprockets are often made as a combined type, and the gear ring and the wheel core can be made of different materials.
Materials
The teeth of the sprocket should be guaranteed to have sufficient strength and wear resistance. Generally, they are heat – treated. Common materials include C45, 40Cr, 20CrMnTi, etc.

I. Working Principle

The driving sprocket and the driven sprocket are connected by a chain. When the driving sprocket is connected to a power source and rotates, its teeth will push the chain to move forward. Since the chain is also meshed with the driven sprocket, the driven sprocket will rotate accordingly, thus achieving the transmission of power and motion.

II. Application Fields

It is widely used in industries such as chemical engineering, textile machinery, escalators, wood processing, stereo parking garages, agricultural machinery, food processing, instruments and meters, and petroleum. It is also used in the transmission systems of vehicles such as bicycles and motorcycles.

III. Maintenance and Upkeep

Adjustment of Tension
The tension of the sprocket should be appropriate. When lifting or pressing down the middle of the chain, it should be about 2% – 3% of the center – to – center distance of the two sprockets.
Inspection of Installation Accuracy
The sprocket installed on the shaft should have no wobbling or skewing. The end – faces of the two sprockets in the same transmission component should be in the same plane.
Treatment of Wear
After the sprocket is severely worn, both the new sprocket and the new chain should be replaced simultaneously. When the tooth surface is worn to a certain extent, it can be used by turning it over.
Adjustment of the Chain
If a new chain is too long or has elongated after use, chain links can be removed, but the number of removed links must be an even number.
Lubrication
Lubricating oil should be added in a timely manner during operation to improve working conditions and reduce wear.
Storage
When the machine is stored for a long time, the sprocket should be removed, cleaned with kerosene or diesel, coated with engine oil or grease, and stored in a dry place.

IV. Ways to Determine Whether a Sprocket Needs Lubrication

Observe the Appearance of the Sprocket
1. Color Change
  Under normal circumstances, the surface of the sprocket has a certain metallic luster. If the surface color becomes dull, loses its luster, or even rust spots appear, this may be due to a lack of lubrication, resulting in the adhesion of moisture or impurities and triggering oxidation and rusting. Timely lubrication and protection measures are needed.
1. Wear Marks
  Carefully check the tooth surface of the sprocket, the connection part of the wheel shaft, etc. If obvious wear marks appear, such as the thinning of the tooth surface, the presence of grooves, or the appearance of worn pits at the connection part of the wheel shaft, it indicates that the friction during the operation of the sprocket is relatively large. This may be due to insufficient lubrication, and lubrication is required to reduce friction.
Listen to the Operating Sound
1. Abnormal Noise
  When the sprocket is operating normally, the sound is stable and relatively quiet. If obvious abnormal noises such as “creaking” or “clicking” are heard during operation, this is likely because there is a lack of lubrication between the sprocket and the chain, between the sprocket and the shaft, etc., resulting in increased friction and the generation of noise. At this time, lubrication of the sprocket should be considered.
1. Sound Change
  If the originally smooth operating sound becomes dull and unsmooth, it may also be a problem with lubrication, causing the operating resistance of the sprocket to increase. It is necessary to check and replenish lubricating oil.
Feel the Operating Resistance
1. Difficult Start – up
  When starting the equipment, if the motor load is felt to be relatively large, the starting speed is slower than usual, or the sprocket needs to be started several times to operate normally, it may be that the sprocket lacks lubrication, resulting in excessive friction and increased start – up difficulty. In this case, the sprocket needs to be lubricated.
1. Unsmooth Operation
  During the operation of the equipment, touch the shaft of the sprocket or related transmission components by hand to feel whether there is obvious vibration or jamming. If so, it indicates that the operation of the sprocket is unsmooth, which may be due to poor lubrication, making the fit between components less smooth. Lubrication treatment is required.
Check the Lubrication Record
1. Regular Inspection
  Establish a lubrication record file for the sprocket. According to the lubrication cycle specified in the equipment operation manual or relevant regulations, regularly check the lubrication condition of the sprocket. If the specified lubrication time interval is exceeded, even if there are no obvious abnormalities on the surface of the sprocket, lubrication should be carried out in a timely manner to ensure its normal operation and service life.
1. Special Circumstances
  If the equipment operates in harsh environments, such as high temperature, high humidity, or a dusty environment, or if the usage frequency of the sprocket has significantly increased and the load has increased recently, even if it has not reached the regular lubrication time, it is necessary to check in advance and consider whether lubrication is required.