Category: Chains and sprockets

Sprocket quenching is necessary because some parts (including sprockets) experience higher stress on their surface layer than their core under alternating loads such as torsion and bending, as well as impact loads during operation. In friction-induced applications, the surface layer is constantly worn down, thus requiring high strength, high hardness, high wear resistance, and high fatigue limit for the surface layer of some parts. Only surface strengthening can meet these requirements. Surface quenching is widely used in production due to its advantages of minimal deformation and high productivity. The purpose of sprocket quenching is to transform supercooled austenite into martensite or bainite, obtaining a martensitic or bainitic structure. This is then combined with tempering at different temperatures to significantly improve the steel's strength, hardness, wear resistance, fatigue strength, and toughness, thereby meeting the diverse requirements of various mechanical parts and tools. The quenching principle involves placing the workpiece in an inductor made of hollow copper tubing…

Medium-frequency quenching: The hardened layer is relatively deep (3-5mm), suitable for parts subjected to torsion and pressure loads, such as crankshafts, large gears, and grinding machine spindles (materials used are 45# steel, 40Cr, 9Mn2V, and ductile iron). High-frequency quenching can harden the surface layer in a short time! The crystal structure is very fine! The structural deformation is small. The surface stress of medium-frequency quenching is smaller than that of high-frequency quenching. 50HZ is called power frequency, with a heating depth of 5-10. 1000-10000HZ is called medium frequency. "High-frequency quenching" and "medium-frequency quenching" are in the same principle, so there are certain criteria for selecting medium-frequency quenching equipment. High-frequency quenching: The hardened layer is shallow (1.5-2mm), with high hardness, the workpiece is not easily oxidized, deformation is small, the quenching quality is good, and the production efficiency is high. It is suitable for parts working under friction conditions, such as smaller gears and shafts (materials used are 45# steel and 40Cr). Above 10000HZ is called high-frequency quenching. High-frequency quenching is mostly used…

The selection of the transmission sprocket should be based on scientific calculations of the chain drive speed (corresponding to the transmission ratio of the sprocket), the chain tension or lifting force (corresponding to the weight of the workpiece and the number of chain rows), the tensioning method (corresponding to the length of the chain), the protective cover (to protect safety during operation), and the installation and disassembly (whether it is convenient for customers to repair or replace). Note: (1) In chain drive, the larger the pitch P, the larger the size, weight and load capacity of the chain. However, the larger the chain pitch P, the more obvious the polygonal effect of the chain will be, and the greater the impact, vibration and noise generated. (2) The number of small sprocket teeth affects the smoothness and service life of the chain drive. The fewer the number of small sprocket teeth, the greater the unevenness of the movement speed and the greater the load. If the number of small sprocket teeth is too large, the profile size and weight will increase, and it is easy to produce tooth skipping and chain derailment. In addition, the chain speed affects the smoothness and service life of the transmission. The higher the chain speed, the more obvious the polygonal effect, and the greater the corresponding dynamic load.

Sprocket Design and Machining 1. Sprocket Design: For standard chains with pitches of 12.7-38.1, manufacturers have adopted standard hobs to produce sprockets on hobbing machines. During machining, users only need to provide the number of sprocket teeth, pitch, and roller diameter. Sprocket design follows GB1244-85. For non-standard sprockets, based on the necessary data provided by the user, the following calculations are required: Pitch circle diameter: d_point = P/sin180 degrees/Z = P·K, P - pitch, K - number of teeth coefficient (can be found in a table). Tooth groove radius: Rmin = 0.505d, d = roller diameter. Pressure angle? Qmin = 120 degrees - 90/2; Qmax = 140 degrees - 90/2. Generally, Qmax is selected. Tooth surface radius Remin = 0.008d; (Z·Z+180); Remax = 0.12 (Z·Z+2). Generally, Remax is selected. Tooth surface radius…

Sprockets are indispensable in our lives, but how much do we really understand them? Let's take a look at their performance. First, the choice of sprocket material: different models of large and small sprockets are all made of high-quality carbon structural steel through stamping. Secondly, the machining and processing technology: It generally uses advanced milling technology, which makes the tooth shape more precise. After machining, the sprocket undergoes heat treatment, which changes its molecular structure, greatly improving its overall mechanical properties. The tooth hardness reaches 68-72 HRA or higher, significantly improving the sprocket's wear resistance. The surface is then treated with powder coating and electroplating. Through machining, heat treatment, and surface treatment, the sprocket becomes more robust and durable.

1) Overall quenching and tempering treatment, induction hardening of the tooth groove surface, and tempering treatment; 2) Surface carburizing, quenching, or tempering treatment. Non-steel sprockets and some non-standard sprockets use other material treatment methods. Common sprocket materials and heat treatment process requirements should be based on customer requirements. For example, for sprockets made of 15 or 20 steel with small tooth blanks and fewer than or equal to 25 teeth subject to impact loads, carburizing, quenching, and tempering should be performed to achieve a tooth surface hardness of 85.7HB15N~90.6HB15N. For larger sprockets made of Q235 or Q275 with low-speed and low-power applications, welding followed by annealing should be performed to achieve a tooth surface hardness of 140HBS.

Generally, first determine the roller diameter and installation spacing, then determine the torque based on the cargo dimensions. 1. Select the geared motor, determining parameters such as torque, speed, and reduction ratio. Choose the same motor for both the drive and driven wheels, with the geared motor handling all reduction. 2. Select the chain specification based on the load and chain speed. 3. Select the sprocket size based on the sprocket motor location, considering factors such as chain specification, installation space, and sprocket wrap angle. Generally, 17-21 teeth are sufficient. Fewer teeth result in a smaller sprocket, leading to unstable transmission due to the polygonal effect, and the increased teeth occupy more space. 4. Select the sprocket shaft and installation method, generally using a clearance fit, flat key connection, and set screw. 5. Draw a design and find a manufacturer for processing. Refer to the design manual for materials and surface treatment. Alternatively, you can buy a similar one on the market; chain drives offer high fault tolerance.

Common Chain and Sprocket Faults and Troubleshooting: 1. Chain vibration at the front of the chain is caused by a loose chain, excessive load, or one or more inflexible links. The solution is to install a chain tensioner or an adjustable center distance, and reduce the load if possible. 2. Chain and sprocket tension is related to the slack side droop of the chain. For horizontal and inclined drives with adjustable center distances, the slack side droop should be approximately 21/3T of the center distance. For vertical drives or drives subjected to vibration loads, reverse drives should be made to tighten the chain further. 3. Poor chain and sprocket fit may be due to chain wear or pitch elongation. If skipped teeth are observed, the chain should be replaced promptly. Worn sprockets should also be replaced to avoid damaging the new chain. 4. The parallelism of the rear axle and the coplanarity of the sprockets are crucial for chain lifespan. Chain performance largely depends on the correct installation of the front and rear axles and sprockets. The requirement is: the parallelism of the front and rear axles should be within 1/…

(1) The resultant force of the radial cutting force and the clamping radial component generated during cutting will cause the workpiece to bend, and the workpiece will vibrate when rotating, thus affecting the machining accuracy and surface quality. (2) When the workpiece rotates at high speed, the bending and vibration of the workpiece will be aggravated due to the centrifugal force. (3) The deformation of the workpiece due to its own weight will aggravate the self-vibration of the workpiece, affecting the machining accuracy and surface quality. (4) The heat treatment of steel will cause the blank to bend and deform, which will seriously affect the subsequent turning process. Straightening treatment is required, which will increase the machining cost.

The most suitable application areas for sprockets include: First, in transmission systems, commonly found in mechanized vehicles and machinery. Their primary application in this area is driving. Second, other speed-related applications, such as industrial gearboxes and vehicle wheel drive systems. Almost all systems using sprockets also require different types of gears; optimal combination of multiple mechanical devices and components is necessary to achieve the best sprocket application results. 1. Before production at the sprocket factory, it is crucial to prepare raw materials. Raw materials are paramount; without them, production is impossible. This is an issue we must carefully consider. Proper storage of raw materials is also essential to prevent losses. 2. Safety is paramount during production, especially for motorcycle sprockets…

Selection of Oil Supply Quantity in Gear Transmissions: 1. Various countries have different concepts regarding the selection of oil supply quantity in gear transmissions. Empirical values, empirical calculation formulas, and conditional calculation formulas are used in parallel. It is not difficult to find that different oil supply concepts stipulate different oil supply quantities for gear transmissions operating under the same conditions. Therefore, the impact on the lubrication and cooling effects of the gear transmission (e.g., anti-galling ability, anti-pitting ability, vibration, noise, and transmission efficiency) also varies. One phenomenon worth considering is that under certain conditions (such as low-speed, small-size transmissions), the oil supply quantities stipulated by various oil supply concepts are very close, and the lubrication and cooling effects are also very good, generally able to transfer more than 90% of the total heat from the tooth surface. In other words, most oil supply concepts can achieve satisfactory lubrication and cooling effects. 2. Under other conditions (such as high-speed, large-size transmissions), various…