Category: Chains and sprockets

Key technology research of high performance circular arc gear pump

Gear pumps are common fluid transfer and conveying components. Due to their simple structure, high efficiency, and resistance to oil contamination, they are widely used in aviation, aerospace, shipbuilding, and automotive industries. With technological advancements, the performance requirements for gear pumps are becoming increasingly stringent, primarily focusing on achieving higher speeds, smaller sizes, and higher pressures. To obtain high-performance gear pumps, it is necessary to research and analyze the new problems arising from high-pressure, high-speed, and miniaturized gear pumps, and to make corresponding improvements and designs to address these issues, providing a basic model and method for future research on high-performance gear pumps. The gear pump rotor is the most crucial component of the gear pump and the foundation and key focus of this thesis. To address the exacerbation of oil trapping and increased flow pulsation with rising pressure and speed, this paper first establishes a basic mathematical model of the gear pump rotor tooth profile, which consists of three segments: a circular arc, an involute, and a circular arc…

Several processing methods of large gears and large sprockets are introduced:

1. Gear milling: This method uses disc-shaped or finger-shaped milling cutters and is a forming machining process. The cross-sectional shape of the milling cutter teeth corresponds to the shape between the gear teeth. This method is not only inefficient but also has relatively low machining accuracy, making it suitable for small-batch production of single pieces. 2. Form grinding: This is also a forming machining method. The grinding wheel is difficult to dress and is used in small quantities. 3. Gear hobbing: This is a forming machining method. Its working principle is similar to the meshing of two helical teeth. 4. Gear shaving: This is a finishing method. It uses a shaving cutter and the gear being machined to perform free meshing motion. Through the relative sliding of the two, finer chips are removed from the tooth surface to improve the precision of the tooth surface. Gear shaving can also create drum-shaped teeth to improve the position of the contact area on the tooth surface. 5. Gear shaping: This is a commonly used gear cutting process besides hobbing, utilizing generating methods. In gear shaping, the cutter and the workpiece…

Machining of sprocket gears by hobbing

Gear hobbing belongs to the generating method and can be regarded as a gear and rack transmission with no meshing backlash. When the hob rotates one revolution, it is equivalent to the rack moving one cutting tooth in the normal direction. The continuous transmission of the hob is like an infinitely long rack moving continuously. When the hob and the hob blank are forced to mesh strictly according to the gear and rack transmission ratio, the envelope of the hob cutting teeth at a series of positions forms the involute tooth profile of the workpiece. With the vertical feed of the hob, the required tooth profile can be hobbed out. Hobbing is currently the most widely used gear cutting method, which can process involute gears, circular arc gears, cycloidal gears, sprockets, ratchet wheels, worm gears, and enveloping worms, with a precision generally reaching DIN 4~7 grade. The advanced hobbing technologies currently include: (a) multi-start hobbing; (b) hardened tooth surface hobbing technology; (c) large gear hobbing technology; (d) high-speed hobbing technology.

Installation requirements and precautions for drive sprockets

(1) Installation Requirements: ① Select the correct drive sprocket model according to the vehicle model specifications. ② Check the condition of the drive sprocket installation location (transmission output countershaft, hub, etc.) to ensure it is in good condition; otherwise, repair or replace the relevant parts. ③ Install the driving and driven sprockets in place using the correct method and tighten the fasteners to achieve the specified torque requirements. ④ After installing the drive chain and adjusting the tension, check whether the chain and sprocket fit smoothly, are coplanar, and do not interfere with the chain guard. (2) Precautions: ① The driven sprocket should have anti-loosening measures. ② After the driven sprocket is installed, the rear wheel axle should be aligned using the adjuster and the rear swingarm (also called the rear wheel fork). This will prevent the rear wheel from running off-center and also avoid premature wear of the sprocket and chain. ③ It is best to replace the sprocket and chain at the same time. Replacing only one of them will aggravate the wear of both. ④ Because the driving sprocket has a high speed and fewer teeth, it wears faster than the driven sprocket under the same conditions, which is normal…

Grinding and milling of sprocket wheels

1. Gear Grinding: Gear grinding is the most effective and reliable method for obtaining high-precision gears. Developed countries use hardened gear surfaces, making gear grinding the primary machining method for high-precision gears. Currently, disc grinding wheels and large flat grinding wheels can achieve gear grinding accuracy up to DIN2 level, but the efficiency is very low. Worm grinding wheels achieve gear grinding accuracy up to DIN3-4 level, with high efficiency, suitable for grinding medium and small module gears, but grinding wheel dressing is relatively complex. The main problems with gear grinding are low efficiency and high cost, especially for large-sized gears. Therefore, improving gear grinding efficiency and reducing costs are the main research directions at present. New technologies in gear grinding in recent years include: (a) double-sided grinding method; (b) high-efficiency gear grinding with cubic boron nitride grinding wheels; (c) continuous forming gear grinding technology and ultra-high-speed grinding technology. 2. Gear Milling: Gear milling is a forming method for machining gears. The cutter's profile is the same as the tooth groove shape of the gear being machined. The cutter feeds along the tooth groove direction of the gear. After one tooth groove is milled, the gear being machined is divided into…

Machining analysis of cast sprockets

Cast sprockets are mainly used in the machining of large sprockets. During machining, only the tooth ring, the two end faces of the flange, the outer and inner diameters, and the keyway are machined, and then the tooth profile is machined. Ring sprockets are all cast. There are generally two materials for cast sprockets: cast iron and cast steel, such as HT15O, HT200, and ZG310-570 (ZG45). Welded structures are mainly used in the machining of medium and large-sized single and double-flange sprockets. During machining, the flange part is machined from bar stock into a convex shape. The tooth ring part can be made by cutting sheet metal, machining the outer diameter and shaft hole, and machining a welding bevel at one end of the hole to fit into the flange part for welding. Welding is done at both ends using low-hydrogen welding rods such as T506 welding rods. Forged sprockets are mainly used in the production of medium and large-sized sprockets subjected to greater forces. During forging, whether single-flange or double-flange, they are generally forged into a convex shape, leaving sufficient machining allowance in the shaft hole. This results in lower material utilization and higher costs. Sprocket machining…

Processing and disassembly process of chain wheel

Typically, sprockets have 24 teeth evenly distributed, with an angle of 15° between any two teeth. The end point of one tooth profile is the starting point of the next. In actual machining, rotating the coordinate system by a certain angle after milling each tooth before continuing milling reduces the workload of programming. To simplify the sprocket machining program, the relative coordinate instruction G91 is used to rotate the coordinate system, eliminating the need to write subroutines for each tooth. Programming is based on machining one tooth profile, with the end point of the machining program for that profile serving as the starting point for the next, and so on. Based on their application, sprockets can be divided into driving sprockets and driven sprockets. Driving sprockets are connected to the engine output shaft via splines and secured with spline baffles or nuts. Disassembly involves removing the sprocket cover and chain, then unscrewing the spline baffle or fixing nut to pull out the small sprocket. Assembly is performed in the reverse order. Driven sprockets…

Spiral bevel gears have a circular tooth shape and their specifications are analyzed.

Spiral bevel gears are available in diameters ranging from 10mm to 1600mm, modules from 1 to 36, and precision grades from GB5 to GB8. Based on different design methods, processing methods, and processing equipment, spiral bevel gears can be categorized into German Klingberg spiral bevel gears, American Gleason spiral bevel gears, and Swiss Olinkon spiral bevel gears, commonly referred to as Klingberg, Gleason, and Olinkon spiral bevel gears. While there are some minor differences between these different types of spiral bevel gears, many of their main parameters are similar. Depending on the application environment, the parameters also vary significantly. Based on the application environment, spiral bevel gears can be further divided into centrifugal classifier series spiral bevel gears, vertical coal mill spiral bevel gears, textile machinery series spiral bevel gears, reducer series spiral bevel gears, automotive transmission series spiral bevel gears, steel rolling mill series spiral bevel gears…

Working principle of rack and pinion power steering

In a rack and pinion steering gear, the steering gear, acting as the driving component of the transmission pair, is mounted in the housing and meshes with a horizontally arranged steering rack. A spring presses the rack against the steering gear via a pressure block to ensure backlash-free engagement. The spring preload can be adjusted using an adjusting screw. During operation, the middle of the steering rack connects to the steering tie rod bracket, and the left and right tie rods connect to the steering knuckle arms. Compared to other types of steering gears, the main advantages of a rack and pinion steering gear are: simple and compact structure; the housing is die-cast from aluminum or magnesium alloy, resulting in a relatively small weight; transmission efficiency up to 90%; and the ability to automatically eliminate backlash caused by wear between the gear and rack (as shown in Figure 1) using a spring with adjustable pressure on the back of the rack near the driving pinion, which not only improves the rigidity of the steering system but also prevents impact and noise during operation. The steering gear occupies a very small volume…

What is the best material for sprockets?

Sprocket materials generally need to meet three requirements: 1) strength; 2) wear resistance; 3) impact resistance (under impact loads). Specifically, there are ordinary carbon steel, high-quality carbon steel, and alloy steel. For larger sprockets (when requirements are lower), refined cast iron can be used, and for low-power transmissions, fabric-reinforced phenolic resin can be used. Note: 1) Under impact loads, low-carbon steel and low-carbon alloy steel are generally used → carburizing, quenching, and tempering. 2) For sprockets without severe impacts and with medium to high speeds, medium-carbon steel and medium-carbon alloy steel are generally used → quenching and tempering. 3) For sprockets with a large number of teeth (extra-large) Z>50 → gray cast iron is used. 4) For medium to low-power transmissions → ordinary or high-quality carbon steel is used. For high and low-power transmissions → alloy steel is used. 5) For P<6KW, high-speed chain drives → fabric-reinforced phenolic resin is used, resulting in lower noise and smoother transmission. 6) The material and heat treatment requirements for small sprockets should be higher than those for large sprockets—because the number of meshing cycles for small sprockets is higher than for large sprockets…

Analyze the principles of sprocket material selection:

Selection principles for sprocket materials: Sprocket materials should meet strength and wear resistance requirements. For low-speed, light-load, or smooth transmission, sprockets can be made of low- or medium-carbon steel; for medium-speed, medium-load transmission without severe impact, medium-carbon steel with quenching treatment is used, with a tooth surface hardness HRC>40~45; for high-speed, heavy-load, or continuous operation transmissions, low-carbon alloy steel with surface carburizing and quenching or medium-carbon alloy steel with surface quenching is used. For low-speed, light-load transmissions with a large number of teeth, cast iron sprockets of at least HT150 are also permissible. Because smaller sprockets have more meshing times than larger sprockets, the material requirements are also higher. When large sprockets are made of cast iron, smaller sprockets are usually made of steel. For plate sprockets that do not require heat treatment, Q235, Q345 (16Mn), or 10 or 20 steel can be used. The hardness is generally below HB140, suitable for medium-speed, medium-power, and larger sprocket machining. Sprockets requiring heat treatment are generally made of 45 steel…

Maintenance of chain wheel

Sprocket Maintenance: 1. The sprocket tension should be appropriate. Too tight a tension will increase power consumption and cause bearing wear; too loose a tension will cause the sprocket to jump and derail. The appropriate tension is: when lifting or pressing down the sprocket from the center, it should be approximately 21-31/3 the center distance between the two sprockets. 2. The sprocket should not wobble or tilt when mounted on the shaft. In the same transmission assembly, the end faces of the two sprockets should be in the same plane. When the center distance between the sprockets is less than 0.5 meters, a deviation of 1 mm is acceptable; when the center distance is more than 0.5 meters, a deviation of 2 mm is acceptable. However, there should be no friction on the side of the sprocket teeth. Excessive misalignment can easily cause derailment and accelerated wear. When replacing sprockets, the misalignment must be checked and adjusted. 3. When the sprockets are severely worn, both the sprocket and the new sprocket should be replaced simultaneously to ensure good meshing. Do not replace only the sprocket or the new sprocket. Otherwise, poor meshing will accelerate the wear of the new sprocket or the new sprocket. …

Analysis of sprocket frequently searched keywords

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The selection method of sprocket chain

Methods for selecting sprocket chains 1. When selecting roller chains, the following 7 conditions should be considered 2. Determine the usage coefficient According to the type of machinery to be transmitted and the type of prime mover, the usage coefficient is determined by using the coefficient table (Table 1). 3. Determine the compensation transmission power (kW) The compensation transmission power (kW) is compensated using the usage coefficient. K For single-row chains E Compensation transmission power (kW) = Transmission power (kW) M Usage coefficient K For multi-row chains E According to the multi-row system  4. Select the number of teeth of the chain and sprocket 5. Select the number of teeth of the large sprocket 6. Check the shaft diameter 7. Shaft spacing of the sprocket 8. Calculate the chain length and the center distance between the shafts of the sprocket Lp: Chain length expressed in terms of the number of links N1: Number of teeth of the large sprocket N2: Number of teeth of the small sprocket Cp: Center distance between shafts expressed in terms of the number of links: ≈3.14 (1) Calculate the chain length (the sprocket diameter has been determined)...

Analysis of the principle of powerful scraping processing and the advantages of powerful scraping

The principle of heavy-duty gear scraping: Heavy-duty gear scraping uses a cutting method that integrates hobbing and shaping to process internal and external cylindrical gears. During the cutting process, the cutting tool acts as both a hob and a shaper. The cutting method involves continuous rotation of the workpiece and the tool, combining the hobbing and shaping motions to cut the gears. During heavy-duty scraping, the tool has an axial angle relative to the workpiece and rotates around its own axis to generate motion. Simultaneously, the tool moves along the workpiece's axial direction to cut the entire length of the workpiece. The shape of the tool is very similar to that of a shaper. When the workpiece has spur teeth, the tool should be a beveled tooth; when the workpiece has beveled teeth, the tool is generally made into a spur tooth. When machining involute tooth profiles, regardless of whether the tool is a spur or beveled tooth, the tooth profile in its end face is involute. The theoretical cutting edge shape of the tool should be manufactured according to the contact line on the tool tooth surface when the tool and workpiece mesh. Therefore, when the tool is a spur tooth, the cutting edge is on the end face of the tool…

How to solve the problems arising in the machining process of sprocket shaft parts

To address the problems encountered during the machining of sprocket shaft parts, the machining scheme was improved by adopting a combined machining method, which reduced the machining difficulty and cost, met the dimensional and precision requirements of the parts, and improved machining efficiency. The main function of the shaft is to support transmission components (gears, sprockets, and pulleys, etc.), transmit torque, and bear loads. Its main structural feature is that its length is greater than its diameter, and it is generally composed of a coaxial outer circle, a cone, an inner hole, threads, and keyways. 1. Analysis of Part Structure and Machining Difficulties The sprocket shaft is a slender shaft of the sprocket drive mechanism of the drying oven in our SPL-1200 printing system. The material is 45 steel, heat-treated (T215). The part has a diameter of 30mm, a length of 1171mm, and a length-to-diameter ratio of 39. It is a slender shaft with very poor rigidity. The machining requirements are a dimensional accuracy of φ30 0-0.009mm at both ends, and the coaxiality of the φ30mm outer circles at both ends…

German-made WERA WERA inserting and rolling machine process characteristics:

Features of the WERA gear shifting machine from Germany: High machining precision, achieving DIN 5-7 grade accuracy; Surface roughness: Rz2-3; High flexibility: One machine can process both internal and external gears; High efficiency: Changeover time is within 30 minutes, requiring only tool replacement, chuck, conveyor mask, and program re-entry; Low tool consumption cost, reusable after repeated sharpening (15-20 times); Dry machining, no coolant required, saving production costs and reducing potential failure points; Clean and environmentally friendly machine tool, no post-processing cleaning required; Pneumatic clamping (5 bar air source), eliminating the need for a hydraulic system, saving production costs; Convenient for inline production: The machine's loading and unloading conveyor can be left-hand, right-hand, or continuous (preliminary confirmation required); …

Tooth shape is not normal - tooth surface out of the edge

Abnormal tooth profile – Tooth edge protrusion is mainly caused by excessive tooth profile error of the hob or inability to divide the teeth effectively. There are four types of workpiece defects: 1) Poor tooth division after hob grinding; 2) Excessive axial runout of the hob; 3) Large radial runout of the hob; 4) Dull hob. The main solutions are to focus on the hob grinding quality, hob installation accuracy, and machine tool spindle geometric accuracy: 1) Control the hob grinding quality; 2) Ensure the hob installation accuracy, and avoid hammering during hob installation; ensure the washer end face is flat; the nut end face is vertical; the inside of the taper hole is clean; and there should be no gap after the bracket is installed; 3) Recheck the rotation accuracy of the machine tool spindle and repair and adjust the hob spindle bearings, especially the thrust washer; 4) Replace with a new hob.