Industry news|2022-03-23| admin
1. Raw material quality control: High-quality raw materials are the premise of producing high-quality products. 40 Cr and 45 steel are the most widely used gear materials produced by our company. No matter how the material enters the factory, chemical composition, particle size determination and virginity evaluation are strictly carried out.
2. Running gear accuracy: Basic requirements for gear accuracy: Practice has proved that the gear accuracy needs to be controlled within GB10995-887~8, the linear speed is higher than 20m/s gear, the limit deviation of the tooth pitch, the radial runout of the ring gear and the tooth direction service needs Stable, to achieve 7-level accuracy. The purpose is to adjust the heat treatment deformation in time and improve the quality of tooth shape processing. In the case of reaching the 7th grade fine gear, it is necessary to analyze the gear accuracy.
3. Prevent heat treatment deformation: After rough machining of gear blanks, thin forgings are formed, normalized or tempered to achieve:
(1) Cut the softened steel parts;
(2) Eliminate residual stress;
(3) Refine the grains, improve the microstructure, and improve the mechanical properties of the steel;
(4) Tissue preparation for final processing. It should be noted that during normalizing or quenching and tempering, the furnace temperature should be kept uniform, and the workpieces should be heated and cooled evenly by using station equipment, and stacking is strictly prohibited. If it is necessary to drill the gears to reduce weight, the drilling sequence should be organized after heat treatment. The final heat treatment of the gear adopts high-frequency quenching of the tooth surface to reduce the deformation of the parts. The tooth surface obtained by induction hardening has high strength, hardness, wear resistance and fatigue limit, while the core still maintains sufficient plasticity and toughness. Cut off deformation. For high-frequency quenching of tooth surface, low quenching temperature and short heating time should be selected, the heating is uniform, and the cooling speed is slow.
4. In order to ensure the accuracy of the gear blank: the accuracy of the gear hole size of the planetary gearbox should be distributed near the middle difference of the hole deviation value, and set at 0.003 ~ 0.005mm; within the design requirements of the hole, it is necessary to separate classification, transfer to the cutting process. Without affecting the strength of the gear, the addendum height coefficient is increased by 0.05 m, which improves the addendum height coefficient of the tool and avoids the interference of the tooth root of the gear transmission. The thread on the mandrel needs to be ground with a thread machine under the C-shaped top positioning: the straightness is less than 0.003mm, and the diameter runout is less than 0.005mm.
5. Selecting high-quality lubricating oil and using it correctly can effectively lubricate the machinery in a timely manner, ensure that the system noise is within a certain control level, and prolong the service life of the machinery and equipment. At the same time, pay attention to the temperature change during operation to reduce the chance of making noise.
6. Before refining the planetary reduction gear, the end face of the gear must be cleaned. Selecting the same machine tool to produce and process the left and right gears is more conducive to ensuring the meshing degree of the gears.
7. Gear cutting method: The purchased gear cutting knife needs to be overhauled to meet the requirements of AA level. Tool accuracy: The radial runout of the tool is controlled below 0. 03 mm, the last 0.04 mm or less. The end runout and radial runout of the blank are grade 6 and are in the range of 0. The 01~0.02 mm nut is necessary to ensure that the inner thread and the base are clamped at one time, and the parallelism of the gasket is less than 0.03 mm. Operators should also frequently self-check, especially the radial clearance of the machine tool spindle should be controlled below 0. 01mm, the east-west axis diameter jumps below 0. 005mm, the east-west axis moves below 0. 08 mm ensures the accuracy of the tool, and the clearance between the outer diameter of the mandrel and the workpiece hole is 0. After grinding from 01 to 0004 mm, it is necessary to overhaul the radial direction of the leading edge of the gear tool, the circumferential difference between adjacent chip grooves, and the chip tolerance. The maximum cumulative error of the joint around the groove, the parallelism of the tool advancing direction and the axis of the inner hole.
8. Select other materials, heat treatment and surface treatment: (1) Select the powder metallurgy forming process for high frequency quenching of the gear. (2) Select 40 Cr data, gear cutting, nitrocarburizing or tooth copper plating. (3) Graphite cast iron, gear cutting and soft nitriding treatment, in order to eliminate gear transmission noise, gear data and heat treatment are the basis to ensure the accuracy of gear blanks, gear accuracy is the pivot, and civilized production is the foundation.
