Ways to reduce gear noise:
In order to avoid that the speed reducer cannot pass the factory test, one of the reasons is that the speed reducer has intermittent high noise; with the ND6 type precision sound level meter test, the low noise speed reducer is 72.3Db(A), which meets the factory requirements; and high noise speed reduction The machine is 82.5dB(A), which does not meet the factory requirements. After repeated testing, analysis and improvement of the test, the conclusion is that it is necessary to carry out comprehensive treatment of all aspects of production in order to effectively reduce the noise of the gear transmission.
1. Accuracy of Control Gears: Basic Requirements for Gear Accuracy: After practice, the accuracy of gears must be controlled in GB10995-887~8, the line speed is higher than 20m/s, the pitch deviation limit, the radial runout tolerance of the gear ring, Tooth tolerances must be stable to achieve level 7 accuracy. In the case of 7-level precision gears, the teeth must be reversed and the root projections must be prevented.
2. Controlling the quality of raw materials: High-quality raw materials are prerequisites for the production of high-quality products. Our company's largest materials, 40Cr and 45 steel, make gears. Regardless of the method used, raw materials go through the strict chemical composition test, grain size measurement, and purity evaluation after they arrive at the factory. Its purpose is to timely adjust the heat treatment deformation and improve the quality of the tooth profile machining.
3, to prevent heat treatment deformation: After rough machining, the tooth blank becomes a precision forging, undergoes normalizing or quenching to achieve:
(1) Soften steel for cutting;
(2) Eliminate residual stress;
(3) refine the grain, improve the organization to improve the mechanical properties of the steel;
(4) Make organizational preparations for eventual handling. It should be noted that, in the normalizing or quenching and tempering process, it is necessary to keep the temperature of the furnace uniform, as well as the use of workstation equipment, so that the workpiece is heated and cooled uniformly, and it is strictly prohibited to pile together. For gears that require drilling to reduce weight, the drilling sequence should be performed after heat treatment. The final heat treatment of the gears uses high-frequency quenching of tooth surfaces that make the part less deformable; the tooth surfaces obtained after high-frequency quenching have high strength, hardness, wear resistance, and fatigue limits, while the core still maintains sufficient plasticity and toughness. To reduce distortion. The tooth surface high-frequency quenching should use lower quenching temperature and shorter heating time, uniform heating and slow cooling.
4, to ensure the accuracy of tooth blanks: the accuracy of the size of the gear hole requirements distributed around the middle of the deviation of the hole value, set at ± 0.003 ~ ± 0.005mm; if the poor and within the hole design requirements, must be classified , respectively, into the cutting process. The end face runout and radial runout of the gear blank are 6 grades and are set in the range of 0.01 to 0.02 mm.
5, cutting gear processing measures: purchased gear cutter must be tested, must meet the AA level requirements. After the grinding of the gear cutters, the radiality of the front blade surface, the adjacent circumferential pitch of the chip flutes, the maximum accumulated error of the flutes of the flutes, and the parallelism of the axis of the front teeth of the cutter teeth must be checked. Under the premise of not affecting the gear strength, the height coefficient of the tooth top is increased by 0.05~0.1m to improve the coefficient of tooth top height of the cutter to avoid interference of gear transmission root. For M=1~2 gears, round top hobs are used, and the rounding radius is R=0.1~0.15m. Eliminates burrs at the top of the teeth and improves interference at the tips of gears during gear transmission. The gear cutting equipment has to perform an accuracy check once a year. If it fails to meet the requirements, it must be repaired. The operator must also perform self-tests frequently, especially when the radial clearance of the machine tool spindle is controlled below 0.01 mm, the diameter of the cutter shaft is below 0.005 mm, and the radius of the cutter shaft is below 0.008 mm. The installation accuracy of the tool: the radial runout of the tool is controlled under 0.003mm, and the end face is below 0.004mm. The precision of the cutting tooling, the gap between the outside diameter of the mandrel and the workpiece hole is guaranteed within 0.001~0.004mm. The thread on the mandrel must be positioned in the C-top position and ground by a threaded bed: vertical ≦0.003mm, radial ≦0.005mm. The nut must ensure that the internal thread and the datum surface are clamped at a time. The parallelism of the washer is 0.003mm.
6, civilized production: gear transmission noise more than 30% of the reasons for glitches, bumps. It is a passive practice for some factories to remove burrs and bumps before the gearbox is assembled. (1) gear shaft parts, hobbing gear teeth immediately after the special plastic protective sleeve put on the next process, and with a special plastic protective sleeve storage and delivery. (2) Carious tooth process to reduce tooth surface roughness, remove burrs, and prevent scratch damage, can effectively reduce gear transmission noise.
7, to take other materials and heat treatment, surface treatment methods: (1) can use powder metallurgy molding technology, gear teeth after high-frequency quenching. (2) The use of black cast iron, gear cutting, and then soft nitriding. (3) 40Cr material is adopted. After gear cutting work, soft nitriding treatment or copper plating on the teeth is adopted. In summary, to solve the gear transmission noise, gear material and heat treatment is the basis, the precision of the gear blank is guaranteed, the precision of the gear is the key, and the civilized production is the basis.
In order to avoid that the speed reducer cannot pass the factory test, one of the reasons is that the speed reducer has intermittent high noise; with the ND6 type precision sound level meter test, the low noise speed reducer is 72.3Db(A), which meets the factory requirements; and high noise speed reduction The machine is 82.5dB(A), which does not meet the factory requirements. After repeated testing, analysis and improvement of the test, the conclusion is that it is necessary to carry out comprehensive treatment of all aspects of production in order to effectively reduce the noise of the gear transmission.
1. Accuracy of Control Gears: Basic Requirements for Gear Accuracy: After practice, the accuracy of gears must be controlled in GB10995-887~8, the line speed is higher than 20m/s, the pitch deviation limit, the radial runout tolerance of the gear ring, Tooth tolerances must be stable to achieve level 7 accuracy. In the case of 7-level precision gears, the teeth must be reversed and the root projections must be prevented.
2. Controlling the quality of raw materials: High-quality raw materials are prerequisites for the production of high-quality products. Our company's largest materials, 40Cr and 45 steel, make gears. Regardless of the method used, raw materials go through the strict chemical composition test, grain size measurement, and purity evaluation after they arrive at the factory. Its purpose is to timely adjust the heat treatment deformation and improve the quality of the tooth profile machining.
3, to prevent heat treatment deformation: After rough machining, the tooth blank becomes a precision forging, undergoes normalizing or quenching to achieve:
(1) Soften steel for cutting;
(2) Eliminate residual stress;
(3) refine the grain, improve the organization to improve the mechanical properties of the steel;
(4) Make organizational preparations for eventual handling. It should be noted that, in the normalizing or quenching and tempering process, it is necessary to keep the temperature of the furnace uniform, as well as the use of workstation equipment, so that the workpiece is heated and cooled uniformly, and it is strictly prohibited to pile together. For gears that require drilling to reduce weight, the drilling sequence should be performed after heat treatment. The final heat treatment of the gears uses high-frequency quenching of tooth surfaces that make the part less deformable; the tooth surfaces obtained after high-frequency quenching have high strength, hardness, wear resistance, and fatigue limits, while the core still maintains sufficient plasticity and toughness. To reduce distortion. The tooth surface high-frequency quenching should use lower quenching temperature and shorter heating time, uniform heating and slow cooling.
4, to ensure the accuracy of tooth blanks: the accuracy of the size of the gear hole requirements distributed around the middle of the deviation of the hole value, set at ± 0.003 ~ ± 0.005mm; if the poor and within the hole design requirements, must be classified , respectively, into the cutting process. The end face runout and radial runout of the gear blank are 6 grades and are set in the range of 0.01 to 0.02 mm.
5, cutting gear processing measures: purchased gear cutter must be tested, must meet the AA level requirements. After the grinding of the gear cutters, the radiality of the front blade surface, the adjacent circumferential pitch of the chip flutes, the maximum accumulated error of the flutes of the flutes, and the parallelism of the axis of the front teeth of the cutter teeth must be checked. Under the premise of not affecting the gear strength, the height coefficient of the tooth top is increased by 0.05~0.1m to improve the coefficient of tooth top height of the cutter to avoid interference of gear transmission root. For M=1~2 gears, round top hobs are used, and the rounding radius is R=0.1~0.15m. Eliminates burrs at the top of the teeth and improves interference at the tips of gears during gear transmission. The gear cutting equipment has to perform an accuracy check once a year. If it fails to meet the requirements, it must be repaired. The operator must also perform self-tests frequently, especially when the radial clearance of the machine tool spindle is controlled below 0.01 mm, the diameter of the cutter shaft is below 0.005 mm, and the radius of the cutter shaft is below 0.008 mm. The installation accuracy of the tool: the radial runout of the tool is controlled under 0.003mm, and the end face is below 0.004mm. The precision of the cutting tooling, the gap between the outside diameter of the mandrel and the workpiece hole is guaranteed within 0.001~0.004mm. The thread on the mandrel must be positioned in the C-top position and ground by a threaded bed: vertical ≦0.003mm, radial ≦0.005mm. The nut must ensure that the internal thread and the datum surface are clamped at a time. The parallelism of the washer is 0.003mm.
6, civilized production: gear transmission noise more than 30% of the reasons for glitches, bumps. It is a passive practice for some factories to remove burrs and bumps before the gearbox is assembled. (1) gear shaft parts, hobbing gear teeth immediately after the special plastic protective sleeve put on the next process, and with a special plastic protective sleeve storage and delivery. (2) Carious tooth process to reduce tooth surface roughness, remove burrs, and prevent scratch damage, can effectively reduce gear transmission noise.
7, to take other materials and heat treatment, surface treatment methods: (1) can use powder metallurgy molding technology, gear teeth after high-frequency quenching. (2) The use of black cast iron, gear cutting, and then soft nitriding. (3) 40Cr material is adopted. After gear cutting work, soft nitriding treatment or copper plating on the teeth is adopted. In summary, to solve the gear transmission noise, gear material and heat treatment is the basis, the precision of the gear blank is guaranteed, the precision of the gear is the key, and the civilized production is the basis.
Acid Printing Auxiliary Series
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