Gear shaft processing technology analysis – processing sequence arrangement

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The machining sequence is arranged according to the principle of base surface first, rough first then fine, main first then secondary. For general parts of gear shaft, after the center hole is prepared, the outer circle is processed first, and then other parts are processed, and it is important to separate rough and fine processing. In the gear shaft processing technology, heat treatment is used as a sign, rough processing before quenching and tempering treatment, semi-finishing before quenching treatment, and fine processing after quenching. After separating the stages in this way, the fine processing of the main surface is guaranteed, and the stress during processing of other surfaces will not affect the accuracy of the main surface.
When arranging the order of gear shaft processes, the following points should also be noted.


(1) The rough machining of the tooth profile of the shaft should be arranged after the semi-finishing of the outer circles of the gear shaft. Because the gear shaft has a relatively large workload and is difficult to process, the processing position should be appropriately placed a little later to increase the positioning height of the positioning reference. The tooth profile finishing should be arranged after all the outer circles of the part are processed, so as to eliminate the heat treatment deformation caused by the local quenching of the tooth profile.
(2) The processing sequence of the outer circle surface should be to process the large diameter outer circle first, and then the small diameter outer circle, so as not to reduce the rigidity of the workpiece at the beginning.
(3) The processing of secondary surfaces such as keyways on gear shafts should generally be arranged after the outer circle finishing or rough grinding and before the outer circle finishing. If the keyway is milled before finishing, on the one hand, before finishing, the vibration caused by intermittent cutting will affect the processing quality and easily damage the tool; on the other hand, the size requirements of the keyway are also difficult to guarantee. These surface processing should not be arranged after the main surface finishing, so as not to damage the main surface accuracy.

Casting of gear rings and gears and how to repair damaged gear rings?

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Large gear rings are important and indispensable parts of equipment, just like gears. Although the two are similar, their main function is to transmit and change the direction of force. However, in addition to this, the protection of the main body of the machine system by the drive of the gear ring cannot be ignored.
The outer teeth of the large gear ring are divided into two types of tooth shapes: drum teeth and straight teeth. It can change the contact conditions of the teeth and improve the ability to transmit torque, thereby meeting the requirements of cost protection and extending the service life. The large gear ring is a thin-walled ring forging. It is easy to have problems such as uneven wall thickness, folding, and ellipse during the forging process. Therefore, the quality of the casting can be improved by controlling the details of the casting process.
Therefore, it can be said that the large gear ring is a very important component for protecting the service life of the machine. So when the large gear is damaged, how should we repair it?

First, the steel castings should be processed. Different processing methods should be used for large gears with different degrees of damage, and the damaged parts of the large gear ring should be processed;

Then, welding should be carried out. Before welding, it should be noted that there should be no impurities such as dirty oil, rust, slag, etc. near the welding part, otherwise it will affect the welding effect;

After the welding treatment, there may still be relatively small pores or sand holes on the surface of the steel casting. After removing these defects, the area should be repaired.

After the welding treatment, the damaged large gear ring can be used normally again, which not only saves the production cost of the enterprise, but also helps to reduce the loss of resources, which can be said to kill two birds with one stone.

About gear transmission types and fault response methods

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When manufacturing gears, several typical errors such as eccentricity, pitch error, base pitch error and tooth profile error are usually generated. There are many reasons for gear manufacturers to generate these errors, including errors from machine tool movement, cutting tool errors, errors from improper installation and debugging of tools, workpieces, and machine tool systems, fixture errors, and gear deformation caused by internal stress during heat treatment. When these gear errors are large, it will cause the gear transmission to rotate slowly and quickly with micro-inertia interference, causing impact and vibration when the gear pair is meshed, causing large noise.

Due to assembly technology and assembly methods, the assembly error of “one end in contact and one end hanging” is usually caused when assembling gears; linear deviation of gear shaft and imbalance of gears, etc. One-end contact or linear deviation of gear shaft will cause uneven load on the gear, causing excessive load on individual gear teeth, causing local early wear, and even causing gear tooth breakage in severe cases. Gear imbalance will cause impact vibration and noise.
1. Tooth fracture
During gear transmission, the action force of the driving gear and the reaction force of the driven gear both act on the other gear teeth through the contact point. The dangerous situation is that the contact point is located at the top of the gear teeth at a certain moment; at this time, the gear teeth are like a cantilever beam. The bending stress generated at the root of the gear teeth after being loaded is large. If it is suddenly overloaded or impact overloaded, it is easy to cause overload fracture at the root of the gear teeth.
2. Tooth surface wear or scratches
Gear teeth have relative sliding during meshing transmission, coupled with poor lubrication, unclean lubricating oil, lubricating oil deterioration, low speed heavy load or poor heat treatment quality, which can cause adhesive wear, abrasive wear, corrosive wear and scratches on the gear tooth surface.
3. Tooth surface fatigue
The so-called tooth surface fatigue mainly includes pitting and peeling of the tooth surface. The cause of pitting is mainly due to the micro fatigue cracks caused by the pulsating contact stress on the working surface of the gear teeth. When the lubricating oil enters the surface crack area, it first closes the entrance and then squeezes during the meshing process. The lubricating oil in the micro fatigue crack area expands the crack area on the gear tooth surface under high pressure, causing the surface metal particles to fall off from the tooth surface, leaving small pits to form pitting on the tooth surface. When the fatigue crack on the gear tooth surface continues to expand deeper and farther, it will cause a large area or large pieces to fall off, forming tooth surface spalling.
4. Plastic deformation of tooth surface
When the gear material is soft and the load transmitted is large, plastic deformation of the tooth surface is easy to occur. Under the action of excessive friction between the tooth surfaces, the contact stress of the tooth surface will exceed the material’s anti-extrusion yield limit, and the tooth surface material will enter a plastic state, causing plastic flow of the tooth surface metal. This causes the active gear to form grooves on the tooth surface near the pitch line, and the driven gear to form ridges on the tooth surface near the pitch line, thereby destroying the tooth shape.

New progress in the manufacturing and application of large-scale mechanical rollers

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New progress in the manufacturing and application of large-scale mechanical rollers: Safety production and industry exchanges are equally important. Recently, a series of new progress has been made in the field of large-scale mechanical roller manufacturing, which not only improves production efficiency, but also expands the application field, and also puts forward higher requirements for safety production.
In terms of manufacturing, the application of new materials makes the rollers have higher strength and wear resistance, and increases the service life of the product. At the same time, advanced manufacturing technology also reduces energy consumption and emissions in the production process, reflecting the concept of green environmental protection.
In terms of application fields, large-scale mechanical rollers are not only widely used in traditional textile, food, medicine and other industries, but also gradually expand to emerging fields such as new energy and environmental protection. Its efficient and stable performance provides strong support for the development of these industries.


Safety production has always been the top priority of the roller manufacturing industry. Recently, the industry has strengthened safety production training and improved employees’ safety awareness and operating skills. At the same time, by introducing advanced safety monitoring equipment and technical means, the safety risks in the production process have been effectively reduced.
In addition, exchanges and cooperation within the industry are becoming more and more frequent. By holding seminars, exhibitions and other activities, enterprises and research institutions are able to share the latest technological achievements and market trends, which has promoted the rapid development of the entire industry.
Looking into the future, the large-scale mechanical roller manufacturing industry will continue to adhere to the development concept of innovation, greenness and safety, continuously improve product quality and application level, and make greater contributions to promoting the transformation and upgrading of my country’s manufacturing industry.

New progress in the manufacturing and application of large-scale mechanical rollers

/in /by

Recently, a series of new progress has been made in the field of large-scale mechanical roller manufacturing, which not only improves production efficiency, but also expands the application field, and also puts forward higher requirements for safe production.
In terms of manufacturing, the application of new materials makes the rollers have higher strength and wear resistance, and increases the service life of the product. At the same time, advanced manufacturing processes also reduce energy consumption and emissions in the production process, reflecting the concept of green environmental protection. In terms of application fields, large-scale mechanical rollers are not only widely used in traditional textile, food, medicine and other industries, but also gradually expand to emerging fields such as new energy and environmental protection. Its efficient and stable performance provides strong support for the development of these industries.


Safe production has always been the top priority of the roller manufacturing industry. Recently, the industry has strengthened safety production training and improved employees’ safety awareness and operating skills. At the same time, by introducing advanced safety monitoring equipment and technical means, the safety risks in the production process have been effectively reduced.
In addition, exchanges and cooperation within the industry are becoming more and more frequent. By holding seminars, exhibitions and other activities, enterprises and research institutions are able to share the latest technological achievements and market trends, which has promoted the rapid development of the entire industry.
Looking into the future, the large-scale mechanical roller manufacturing industry will continue to adhere to the development concept of innovation, greenness and safety, continuously improve product quality and application level, and make greater contributions to promoting the transformation and upgrading of my country’s manufacturing industry.

Why are most gears forged instead of cast now?

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In the past, gears were usually made by casting, but now more and more gears are produced by forging.

1. Forging can provide higher strength and toughness. Gears are subjected to huge pressure and load during operation, so their materials must have sufficient strength and durability. In contrast, gears made by casting usually have internal defects and holes, which reduce the strength and toughness of the gears. The forging process can plastically deform the metal raw materials by heating and hammering, eliminate internal defects, and make the gear materials have higher strength and toughness.

2. Forging can provide higher precision and quality. During the casting process, liquid metal is filled through the mold and cooled and solidified, which may cause uneven shrinkage or deformation of the gear surface. These deformations affect the precision and quality of the gear. In the forging process, by heating and hammering the metal, the metal raw materials can be uniformly plastically deformed, thereby ensuring the precision and quality of the gear.

3. Forging can also save materials and costs. During the casting process, due to the free flow of liquid metal, a certain degree of waste will be generated. The forging process, on the other hand, presses the metal raw material into the desired shape without the need for additional material consumption. In addition, the forging process can also reduce production costs by reducing subsequent processing steps, such as reducing milling, grinding and other operations.

Fourth, the forging process also has the advantage of environmental protection. In the casting process, a large amount of fuel is often required to heat the metal, and a large amount of waste gas and waste slag is generated. The forging process can plastically deform the metal raw material by heating and hammering, and does not require a large amount of fuel, thereby reducing pollution to the environment.

Therefore, the forging process provides higher strength and toughness, higher precision and quality, material and cost savings, and environmental advantages. Therefore, the current forging process will play an increasingly important role in gear manufacturing.

How to choose the material of the large gear ring of the drum dryer?

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The large gear ring of the drum dryer plays a very important role in the entire dryer transmission system. The quality of the large gear ring directly affects the operation and life of the dryer. To choose a good quality large gear ring, you need to understand from the following aspects?
Material selection and hardness requirements of the large gear ring of the dryer:
First of all, we need to know the working environment of the dryer gear ring. Therefore, the requirements for large and small gears are higher than those for gears in general transmission mechanisms. The material of the large gear is ZG45, and it is normalized. The surface hardness of the tooth top circle after processing is HB240-270; the material of the small gear is zg45; because the weight of the dryer itself and the weight of the material are not too heavy, in general, the small gear of the small dryer is mostly made of zg45#. While designing, the manufacturer should also make reasonable configuration according to the actual situation.


Common dryer large gear ring parameters are as follows:
0.8m dryer special gear ring modulus 10 teeth 98, 1m dryer special gear ring modulus 12 teeth 107, 1.2m dryer special gear ring modulus 12 teeth 127, 1.4m dryer special gear ring modulus 14 teeth 140, 1.5m dryer special gear ring modulus 14 teeth 130, 1.6m dryer special gear ring modulus 14 teeth 149, 1.8m dryer special gear ring modulus 14 teeth 149, 2m dryer special gear ring modulus 14 teeth 164
Hengchang Heavy Industry Co., Ltd. can design and customize production services according to customer requirements, welcome to consult

How to extend the service life of rollers

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As a processing and manufacturing tool, rollers are widely used in factories. Their functions cannot be replaced by other roller products. Of course, the quality requirements for rollers are also very high. After the roller is used for a period of time, various wear problems will occur. In serious cases, the roller may not be able to continue working.
The service life of the roller is generally 8 hours. After that, groove wear and crack fatigue will occur. If the grooves caused by wear are deep, steel sticking and jamming will occur. The plasma aluminum guide roller has obvious resistance to abrasive wear and thermal fatigue. After repairing the roller shaft, the effect is obvious. Plasma cladding technology is used to coat the surface of 45 steel with Al2O3-doped Fe-Ni-based high-temperature anti-wear alloy coating, which can improve the anti-wear and anti-cracking performance of the roller. The application of plasma cladding technology on rollers reduces the labor intensity caused by frequent replacement and reduces the wasted steel rolling work time in disassembly, assembly and transportation of rollers, and can increase the amount of steel rolled, saving a large amount of high-quality steel. At the same time, quality problems caused by roller damage can also be avoided.


From the introduction of the above article, we can know the methods to improve the service life of the rollers, which should be of great help to relevant people. There are many types of rollers on the market. The different materials used to make the rollers will have a great impact on the quality of the rollers and also on the performance of the rollers. For roller manufacturers, roller production needs to be carried out according to formal steps. Improper operation during the production process will greatly affect the quality of the rollers.

What is a herringbone gear and what are the advantages of a herringbone gear?

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Helical gears have a lateral force on the axis. In order to eliminate this force, a gear is made into a helical gear with symmetrical opposite directions to eliminate this force. It looks like a herringbone, which is called a herringbone gear for short. Herringbone gears have the advantages of high overlap, small axial load, high load-bearing capacity, and stable operation. The herringbone gear base is used to transmit the torque of the main motor or motor unit to the roller. Herringbone gears cannot be processed by gear shaping or hobbing.
Herringbone gear advantages:


1. Herringbone gears have a high degree of overlap, with at least 2 teeth meshing at any time.
2. The meshing process between the teeth of herringbone cylindrical gears is a transitional process, and the force on the gear teeth gradually increases from small to large, and then from large to small; herringbone gears have high load-bearing capacity and stable operation.
3. Herringbone tooth theory Because the tooth helix angles are in opposite directions in the symmetry direction, there is no or very small axial force.

What are the possible causes of abnormal vibration of the large ring gear of the rotary kiln?

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1. Rotary kiln kiln body parts wear and overall sinking. The rotary kiln is a large-load continuous operation equipment. After long-term operation, the rolling ring, supporting wheel, backing plate and other parts wear greatly, and the uneven foundation settlement causes the overall kiln body to settle. decreases, causing the tooth tip clearance to become smaller, causing vibration. Sometimes, although the overall kiln line does not drop, the support position close to the large ring gear drops, which also causes the large ring gear to vibrate. This is due to the foundation of the support position sinking or being severely worn, or due to improper kiln adjustment.
2. Caused by wear of connecting parts. The ring gear is connected to the kiln body through a spring plate pin. The ring gear itself is manufactured in sections and is integrated into a whole by using countersunk screws. After the pins, countersunk screws, and these connecting parts are worn, the ring gear components will loosen and the local ring gear will sink, which will also cause the tooth top clearance to become smaller and cause vibration. From a maintenance perspective, the only solution is to replace (or tighten) the corresponding screws. Of course, for countersunk screws, from the perspective of design and manufacturing, it is better to make the ring gear as a whole (or tightly connected) instead of connecting it with countersunk screws, so as to fundamentally eliminate the vibration cause (large tooth factor). The fact that the flaps are made to be turned over is another issue. Practice has proved that the large ring gear has a simple tooth shape and a low rotational speed. It can still operate normally after half of the tooth thickness is worn).


3. The cylinder at or around the ring gear is bent, causing the large ring gear to deflect excessively in the radial direction and cause vibration. This is manifested in the fact that during the meshing operation of the large ring gear and pinion, the top clearance is smaller for half a turn and smaller for half a turn. The vibration is also a periodic half-vibration. Therefore, the real cause of vibration is that the top clearance is too small.
4. Problems with the ring gear itself. The top clearance of the transmission gear is generally 0.2-0.25 times the module. Due to its large outer diameter and radial deflection of the large ring gear of the rotary kiln, the top clearance is 0.28 times the module plus 0.5-1mm. At the same time, it is required that the radial runout and axial deflection of the large ring gear should not be greater than 2mm after installation. Most of the large ring gears are caused by runout or deflection. Since the large ring gear is connected to the kiln body through the spring plate shaft pin, the large ring gear itself is made into two half rings and combined into a whole with countersunk screws.
5. Vibration caused by tooth thickness wear. The vibration caused by this reason appears as continuous and rhythmic vibration, which can be observed through the meshing of the large ring gear and pinion.
6. The pinion gear is not installed in place. In most rotary kilns, the large ring gear and the two pinion gears form an equilateral triangle in the ideal meshing state, but the angle has changed after long-term operation.