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Gears, as the basic and key components in the mechanical field, play a vital role in various mechanical equipment with their unique structure and function. This article will discuss the processing technology of gears in depth, in order to provide reference for professionals in related fields.

Basic structure and function of gears
Gears are mechanical parts with toothed shapes, which transmit power and motion by meshing with each other. Gears are composed of two major parts: the ring gear and the wheel body. Gears with different functions will be different in design, but the basic structure remains the same. Common types of cylindrical gears include disc gears, sleeve gears, internal gears, shaft gears, fan gears and racks, among which disc gears are the most common due to their wide application.

Precision requirements for gears
The manufacturing accuracy of gears directly affects the working performance, load-bearing capacity and service life of mechanical equipment. According to the conditions of use, gear transmission needs to meet the following accuracy requirements:
1. Motion accuracy: ensure that the gears can accurately transmit motion, maintain a constant transmission ratio, and limit the angular error within a certain range.
2. Working stability: The gears are required to be stable during movement, reduce impact, vibration and noise, and limit the change of angular error in a short period.
3. Contact accuracy: Ensure that the gears have uniform contact on the tooth surface when transmitting power to avoid premature wear caused by uneven load distribution.
4. Tooth side clearance: Leave an appropriate gap between the non-working tooth surfaces to store lubricating oil and compensate for dimensional changes and processing and assembly errors.

Material selection of gears
The material selection of gears has a direct impact on their processing performance and service life. Common gear materials include medium carbon steel, low and medium carbon alloy steel, and for gears with higher requirements, special materials such as nitrided steel may be selected. Non-power transmission gears can also be made of cast iron, cloth-reinforced bakelite or nylon.

Heat treatment process of gears
The heat treatment process in gear processing is mainly divided into two types:
1. Blank heat treatment: Normalizing or tempering treatment is performed before and after the gear blank is processed to eliminate residual stress, improve the machinability of the material, and improve the mechanical properties.
2. Tooth surface heat treatment: After tooth processing, carburizing quenching, high-frequency induction heating quenching and other processes are often used to improve the hardness and wear resistance of the tooth surface.

Gear tooth processing method
Gear tooth processing is the core link of gear processing, including forming method and development method. The forming method uses forming tools that match the tooth shape, such as milling, pulling and forming grinding. The development method is that the gear tool and the workpiece perform development movements according to the meshing relationship, such as hobbing, gear shaping, shaving, grinding and honing.

Tooth end processing
Tooth end processing includes rounding, chamfering, chamfering and deburring. These processes can reduce collision, remove sharp edges and burrs, and improve the meshing performance of gears.

Gear precision requirements
The manufacturing accuracy of gears directly affects the working performance, load-bearing capacity and service life of mechanical equipment. According to the conditions of use, gear transmission needs to meet the following precision requirements:
1. Motion accuracy: ensure that the gear can accurately transmit motion, maintain a constant transmission ratio, and limit the angular error within a certain range.
2. Working stability: require the gear to be stable during movement, reduce impact, vibration and noise, and limit the change of angular error in a short period.
3. Contact accuracy: ensure that the gear tooth surface contacts evenly when transmitting power to avoid premature wear caused by uneven load distribution.
4. Tooth side clearance: leave an appropriate gap between non-working tooth surfaces to store lubricating oil and compensate for dimensional changes and processing and assembly errors.

Material selection of gears
The material selection of gears has a direct impact on their processing performance and service life. Common gear materials include medium carbon steel, low and medium carbon alloy steel, and for gears with higher requirements, special materials such as nitrided steel may be selected. Non-power transmission gears can also be made of cast iron, cloth-reinforced bakelite or nylon.

There are two main types of heat treatment processes in gear processing:
1. Heat treatment of blank: Normalizing or tempering treatment is performed before and after gear blank processing to eliminate residual stress, improve material machinability, and improve mechanical properties.
2. Tooth surface heat treatment: After tooth shape processing, carburizing quenching, high-frequency induction heating quenching and other processes are often used to improve the hardness and wear resistance of the tooth surface.

Processing process of spur gears

The processing process of high-precision gears includes blank forging, heat treatment, profile processing, tooth surface processing, chamfering, deburring, high-frequency quenching, key slot insertion, grinding and other steps, each of which has an important impact on the performance of the final gear.

Gear processing process analysis

In the process of gear processing, the selection of positioning reference, processing of gear blanks, and processing of tooth ends are all key links. Correct positioning reference can improve production efficiency and processing quality, and the processing of gear blanks provides the necessary reference for subsequent tooth surface processing and testing.

Through a comprehensive analysis of the gear processing technology, we can better understand the complexity and sophistication of gear manufacturing, and how to ensure the performance and quality of gears through precise process control. In actual production, every detail cannot be ignored, only in this way can high-quality gears that meet the requirements be manufactured.

With the enhancement of forging technology and the lightweight requirements of automobiles, cast gears have gradually been eliminated by gear companies, and the automotive gear manufacturing industry has begun to apply more forging forming technology. Gear precision forging forming is a high-quality, efficient and low-consumption advanced manufacturing technology. In recent years, it has been widely used in the mass production of automotive toothed parts.

Characteristics of forged gears:

1. The internal structure of forged gears is dense, high strength and long life.

2. Not only is the appearance beautiful, the working hardness is also greatly improved, and it contains very few impurities.

3. The explosion-proof performance is more reliable and higher in level, and can be used in strict working conditions.

Characteristics of castings:

1. The internal structure of castings is worse, the strength is low, and it is easy to have sand holes, shrinkage, and easy to break and deform.

2. It can be used under general working conditions, and the explosion-proof level is lower than that of forging process tools.

3. There are more oxide scales on the surface, and it is difficult to remove them even with oxide scale cleaning machines.

At present, the country advocates green environmental protection, and castings have gradually been listed as obsolete series. Those who have the conditions have changed from casting to forging. Because of market demand, it is normal for everyone to face transformation. The greater the demand, the higher the requirements for the process, so if you want higher precision gears, you can add Litai oxide skin cleaning machine.

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 and local early wear, and even cause 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.

Rotary kiln large gear ring processing manufacturers can produce various large gear rings according to drawings, and can ensure the product quality of large gear rings. So how should the large gear ring be adjusted during use?
1. The construction process of the rotary kiln large gear ring is as follows: divide the circle between the large gear ring and the cylinder into four equal parts, make a tool bracket for disassembly and adjustment, and fix the large gear.
Remove the bolts and locating pins at the connection of the two rings, and use a carbon arc air gouging to remove the spring sheet connecting the large gear ring to reduce the burn to the cylinder when removing the weld. After all the welds of the spring sheet are removed, use a crane to lift the two gear rings to the hard and flat ground on site, and then remove the connecting bolts between the spring sheet and the large gear ring. The connecting hole between the large gear ring and the spring sheet is re-drilled, and the bolt size is determined by the matching hole size. After the pinion and shaft are lifted and removed by the crane.

2. Correction of the rotary kiln large gear ring and spring plate. Lift the gear ring onto the prepared fixture bracket, and tighten the connecting bolts and positioning pins at the connection of the two gear rings of the large gear ring. Ensure that the joints of the two half teeth fit tightly, and use a 0.04mm feeler gauge to check around the mouth, with an insertion depth of no more than 100mm. Make two micrometer fixtures to detect the radial and end face swing of the large gear ring, divide 12 measuring points equally around the large gear ring, and use a rotary kiln to divide 12 measuring points equally around the large gear ring, record the test values, and adjust the radial and end face swing values ​​of the large gear ring through the bracket and adjustment fixture installed on the large gear ring. Now, the large gear ring has been running for several years. When adjusting, the radial and end face swing values ​​of the adjusted large gear ring should be controlled within 2.0mm and 2.5mm as much as possible under the premise of satisfying the normal operation of the large gear ring. Only after the radial and end face swing values ​​of the large gear ring are adjusted, can the connecting spring sheet be installed. The spring sheet and the barrel should be polished flat and tightly connected. The spot welding and welding of the spring sheet and the barrel should be carried out symmetrically to reduce deformation after welding.

3. Correction of pinion, reducer, main motor and auxiliary motor. The clearance between the top of the pinion and the large gear should be controlled at 0.25M+(2-3)mm, the tooth surface contact, tooth height and tooth length should not be less than 40% and 50%, and the coaxiality of the pinion shaft, reducer, main motor and auxiliary motor transmission shaft should be controlled at no more than 0.2mm.

Recently, many customers have asked how to choose the material suitable for the large spindle shaft, and how to choose the hard spindle material suitable for their products. Today, Hengchang Heavy machinery will introduce to you how to choose the material.

The hardness of the large spindle shaft is a relatively important parameter. Whether the hardness is appropriate is directly related to the quality of the product.

The hardness of the motor spindle will vary depending on the material, and the process selected during processing will also be different. At present, the common process treatments include the hardness of the raw material itself and the heat treatment process to harden. Some products have special structures, such as the need to punch ribs on the surface of the product, so the material of the motor spindle cannot be too hard, and some motor shafts have retaining rings, so the hardness range of the motor spindle is between HV500-600. It is more appropriate. If the material selected for the motor spindle is SUS420 series stainless steel, then the hardness range of HV260-320 is more appropriate. But remember that the hardness of the motor spindle cannot be too high. Sometimes the bearing capacity requirement is not very high, so it is enough to slightly temper the motor shaft. Some parts have special requirements, which can be quenched and chrome-plated.

Hengchang heavy machinery is a large-scale mechanical processing manufacturer, specializing in processing various large spindle shaft , gear shafts, spline shafts, gears, and racks. Welcome to consult!