In recent years, China is moving towards becoming a manufacturing powerhouse, and the speed reducer is developing towards high speed, noise reduction, high stability, and miniaturization. The gears of the speed reducer have different processing technologies according to the application scenarios, and different processing technologies have different effects on the later use of the gears. During the working process of the speed reducer gear, pitting corrosion, tooth wear, tooth bonding, tooth fracture and other phenomena often occur. This article mainly takes the cylindrical gear reducer as an example to explore how to extend the service life of the gear.
Tooth breakage
When the reducer is working, the root of the gear teeth is subjected to large alternating stresses, and there is considerable stress concentration at the root of the gear teeth After cyclic loading, when the stress value of the mechanical structure exceeds the strength limit, fatigue cracks will occur, which will continue to expand and eventually cause failure The gear teeth are broken.
Tooth surface pitting
When the gear is repeatedly subjected to contact stress, cracks appear on the gear surface. During operation, the lubricant is squeezed in, and the cracks gradually increase, resulting in tooth surface The metal particles peel off, forming small pits, causing vibration, noise, unstable transmission, and resulting in reduced load capacity.
Tooth surface bonding
When the reducer operates at low speed and heavy load, the pressure between the meshing gear tooth surfaces increases, the local temperature of the tooth surfaces rises too high, the oil film breaks, and the tooth surfaces come into direct contact with each other. The metal between the tooth surfaces may adhere to each other. When the tooth surfaces wear, friction and wear are caused between the tooth surfaces during meshing. The tooth surface wear causes The tooth profile of the gear is damaged, resulting in reduced transmission accuracy, increased noise, increased impact force, thinning of the gear teeth, and potential breakage.
Tooth surface wear
During the meshing transmission process, the tooth surfaces of the reducer gears will slide against each other, and the dust and hard particles between the tooth surfaces will cause wear and tear When this wear reaches a certain level, the gap between the tooth sides will increase, resulting in greater impact and noise, and may even lead to tooth breakage Broken.
Plastic deformation of tooth surface
During the operation of the reducer, due to factors such as excessive stress, frequent starting, and overload, the gear teeth may undergo plastic deformation. This
This deformation is caused by the yielding of the gear teeth, resulting in greater noise and vibration during gear engagement.
The structure of the gear and its correct installation
Professional technicians can predict the life of the gear based on the working environment and load of the reducer, supervise the assembly of the reducer, Select appropriate gear materials and heat treatment processes. When installing gears on the equipment, they should be installed according to the type of gear. During installation, strictly follow the installation procedures The installation process and steps are to be followed, and the installation is to be carried out using tools. After installation, debugging and inspection should also be carried out to ensure the accuracy of the gear installation and improve the quality of the gear Contact accuracy, so as to reduce pitting corrosion. If there are any abnormalities, they should be rectified in a timely manner.
Strengthen the maintenance of gears
Regularly check the bearings and seals of the gear to maintain their good working condition. If necessary, replace the damaged or aged bearings and seals in a timely manner. Carefully inspect the oil seals of the gear and its surrounding components. The oil seal is a very fragile part, and special care is required during inspection and disassembly to avoid damaging the gear. Even if the oil seal does not produce adverse effects for the time being, it should be replaced regularly because poor oil seals will affect the life of the gear and cause equipment downtime. Regularly use cleaning agents or compressed air to clean the gear to remove oil, dust, and other contaminants on the gear surface. Ensure that the gear is in good working condition. Select suitable lubricants or greases, which need to consider factors such as gear materials, usage environment, load, and speed. Generally, lubricants are suitable for high-speed gears, while greases are suitable for low-speed gears. At the same time, parameters such as viscosity and temperature range of lubricants or greases need to be considered. When the oil temperature is too high, the viscosity of lubricants will decrease significantly, affecting the formation of oil film between gear teeth. When the lubrication film on the gear meshing surface becomes thin, the carrying and wear resistance of the tooth surface decreases, which is prone to pitting corrosion on the tooth surface. In parts where lubricating grease cannot be used, solid lubricants can be sprayed onto the gear tooth surface to form a film after the tooth surface dries. The film thickness can be calculated through an elastic flow lubrication model. The thicker the film thickness, the better the lubrication condition of the gear, which can effectively prevent fretting corrosion during the running-in stage of the gear. At the same time, regular replacement of lubricants or greases is necessary to maintain a good lubrication condition of the gear. The replacement time of lubricants and greases needs to be determined according to specific circumstances. It is generally recommended to replace lubricants or greases at least once a year. In addition, check the quantity and quality of lubricating oil, and replace it if it does not meet the specified requirements. When the quantity is low, it should be added in time.
It is necessary to conduct detailed inspections on the operating conditions of the gears on a regular basis, including their wear, deformation, cracks, and other conditions. These inspections can be completed by disassembling the gears or using specific inspection tools. If serious wear problems are found in the gears, they must be replaced immediately to prevent further losses. During the operation of the gears, the operation of the gear set will be directly affected by the wear of the gears. Therefore, once signs of gear wear are discovered, they must be replaced immediately to ensure the normal operation of the system.
Enhance the surface hardness of the reducer gear
Surface heat treatment is a common method used to increase the hardness of gears. Common surface heat treatment methods include carburizing, nitriding, quenching, etc. Among them, Carburizing and nitriding are suitable for gears produced in large quantities, while quenching is suitable for small-scale production or individual gears. During surface heat treatment A hard alloy layer is formed on the gear surface, thereby improving the wear resistance and hardness of the gear.
Carburizing is a surface heat treatment method in which carbon elements are infiltrated into the surface of the gear. This method can form a layer of high carbon compounds on the surface of the gear, which can improve the wear resistance and corrosion resistance of the gear The gold layer improves the hardness and wear resistance of the gear. The carburizing method is suitable for gears made of low carbon steel, alloy steel, cast iron, and other materials. Among them, gas
Carburizing is a process in which a workpiece is placed in a sealed gas carburizing furnace, heated to austenitize it, and then carburizing agents are dripped into the furnace or a carburizing atmosphere is directly introduced into the furnace, allowing carbon atoms to penetrate the surface of the workpiece, thereby increasing the carbon content of the surface of the workpiece.
Reasonable material selection
A reducer is a mechanical device that can increase torque and reduce speed, and is widely used in various mechanical equipment to meet various operational requirements.The reducer gear is the main stressed component, which is mainly subjected to the forces of gear transmission and axial force. Among them, the gear transmission force includes tangential The force and radial force directly affect the life of the gear. The direction of force on the gear is not constant, but changes periodically, which means that the gear is subjected to alternating loads. The force on the gear varies depending on the type of reducer, so it is necessary to make reasonable choices based on different situations when selecting materials. The general principle of material selection is to choose materials with good hardness, strength, toughness, and wear resistance to process the gears of the reducer, such as hard alloys, high-speed steel, and special alloy steel.
Improve the machining accuracy of gears
The machining accuracy of the reducer gear directly affects the service life of the gear, and improving the machining accuracy of the gear indirectly improves the hardness of the gear. The machining accuracy of gears is low, and the surface quality of gears is also affected, resulting in a decrease in surface hardness. Therefore, improving the machining accuracy of gears can To extend the service life of the gear. (1) Reduce the casting error of the gear blank. The error of the gear blank has a fundamental impact on the accuracy of gear processing, especially for high-precision gears. Most gear processing uses its inner hole and end surface as a positioning reference, which affects the subsequent processing, installation, and positioning accuracy of the gear. During the gear hobbing process, if the installation gap of the gear blank is large, it may lead to eccentricity in the processing of the gear blank, resulting in large deviations in the runout of the gear ring, affecting the subsequent processing of the gear, and even causing failure in the processing of the gear. Therefore, it is necessary to strictly control the processing quality of the gear blank to ensure that the accuracy of the reducer gear hole, the outer diameter of the gear blank, and the dimensional accuracy and runout of the outer circle of shaft-type gear blanks meet relevant technical requirements. (2) Carefully inspect machine tool components before processing the gear. The gear processing machine tool has a direct impact on the processing accuracy of the gear, and most of the reasons for low gear processing accuracy are that the machining accuracy of the machine tool cannot meet the requirements
Therefore, it is necessary to select the cutting tool reasonably according to the gear blank material and the accuracy of the gear to meet the processing requirements. The clamping error of the gear will also affect the machining accuracy Affecting the processing accuracy of the gear, the manufacturing and installation accuracy of the hobbing fixture is not high, which will produce radial runout and tooth direction errors of the gear ring. The installation accuracy of the gear blank also depends mainly on the manufacturing and installation accuracy of the fixture. Therefore, reducing the clamping error of the gear can also improve the processing accuracy of the gear. There are many factors that affect the processing accuracy of the gear. The processing environment of the gear has an impact on the processing accuracy of the gear. Various factors in the process of gear processing also affect the processing accuracy of the gear. Therefore, in order to improve the processing accuracy of the gear, first of all, we must enhance the quality awareness of the processing personnel, starting from all aspects of gear processing, including various production links and processes such as gear processing machine tools, fixtures, and cutting tools, strictly controlling the quality checkpoints of each link to ensure the scientific and standardized process of gear processing, thereby ensuring the improvement of gear accuracy.
Optimizing the processing technology of reducer gear
The wear of the tooth surface can be reduced by optimizing the structural design of the gear tooth surface, such as the shape, size, and number of teeth, to reduce the sliding friction and thermal stress between the tooth surfaces. At the same time, surface carburizing and hardening processes can be used to improve the hardness and wear resistance of the gear surface, extending its service life. The machining accuracy of the gear will affect the wear of the tooth surface, so improving the machining process and increasing the machining accuracy can reduce the sliding friction between the tooth surfaces and reduce the wear of the tooth surface. At the same time, high-quality raw materials and advanced heat treatment processes can be used to improve the hardness and wear resistance of the gear material. Before determining the values of main parameters such as gear transmission ratio, a detailed analysis based on the motion of the transmission chain is needed. For the establishment of the gear transmission ratio, the relationship between module and tooth number should be considered. Appropriately increasing the module can reduce the number of teeth, making the gear structure more robust and capable of withstanding greater load forces, thus avoiding the occurrence of tooth breakage and tooth surface wear. However, increasing the module will also lead to larger gear size and weight, which may bring certain inconvenience to transportation and installation. Conversely, reducing the module can help reduce the contact stress of the gear, extending its service life, while also reducing gear noise and vibration, improving transmission smoothness. When determining the gear module, a reasonable choice needs to be made based on actual conditions.
Conclusion
The types and processes of reducers in China are constantly updated, but in order to meet the requirement of minimum cost, it is crucial to extend the service life of the reducer. This article starts with the failure modes of reducer gears, and comprehensively analyzes various ways to install and repair the reducer gears, improve the surface hardness of the gears, and improve the processing technology, so as to effectively extend the service life of the gears and continuously promote China’s development towards a mechanized power. In the actual production process of reducers, designers should conduct comprehensive analysis according to the working requirements of reducer gears and the basic principles of processing gears, and reasonably design the gears to fully extend the service life of the gears.