1. Accuracy of manipulating gears
Basic requirements for gear accuracy: After practical certificati...
1. Accuracy of manipulating gears
Basic requirements for gear accuracy: After practical certification, the gear accuracy must be controlled at the GB10995-887~8 level, the angular speed is higher than 50m/s gear, the limit error of the pitch, the dimensional tolerance of the axial vibration of the gear, and the dimensional tolerance of the tooth direction must be stable. Achieve level 7 accuracy. Under the condition of achieving grade 7 precision gear, the tooth part must be reversed, and the gear tooth punch must be resolutely eliminated.
2. Manipulate the quality of raw materials
High-quality raw materials are necessary for the production of high-quality goods. No matter which method is used, the raw materials need to undergo rigorous composition testing, grain size measurement, and purity identification after they arrive at the factory. The purpose is to immediately adjust the heat treatment deformation and improve the quality in the production and processing of the tooth profile.
3. Avoid heat treatment deformation
After the initial processing, the tooth blank is refined into a steel casting, and quenching or heat treatment is carried out to achieve:
(1) Softened iron castings are convenient for drilling production and processing;
(2) Reduce internal stress;
(3) Optimize the crystal and improve the mechanism to improve the physical properties of the steel;
(4) Make institutional preparations for the solution. It should be noted that during quenching or heat treatment, it is necessary to maintain a uniform temperature in the furnace, and to use fixtures to uniformly heat and cool the product workpieces, and it is forbidden to stack them together. For gears that need to be punched to reduce the net weight, the punching sequence should be allocated after heat treatment. The heat treatment of the gear adopts induction hardening of the journal which makes the deformation of the part smaller; the journal obtained after induction hardening has high compressive strength, strength, wear resistance and fatigue strength, while the core still maintains good plastic deformation and ductility . to reduce deformation. Induction hardening of journals should adopt lower heat treatment temperature and shorter heating time, uniform heating and slow cooling.
5. Ensure the accuracy of the gear blank
The accuracy of the specification of the gear hole is stipulated in the positive and middle difference of the error value of the hole. Process flow. The inner hole vibration and axial vibration of the gear blank are grade 6, which is set in the range of 0.01~0.02mm.
6. Countermeasures for the production and processing of front teeth
The purchased gear CNC inserts must be tested, and the AA-level regulations must be met. After grinding the gear CNC insert, it is necessary to test the axiality of the front edge of the CNC insert, the adjacent circumference of the chip flute, the accumulated error value of the circumference of the chip flute, and the flatness of the front edge of the reaming drill and the centerline of the internal thread. Under the premise of not compromising the compressive strength of the gear, the tooth top index is increased by 0.05~0.1 meters, and the tooth top index of the CNC blade is improved to prevent the interference of the gear teeth of the gear transmission. For gears of M=1~2, the meshing angle rounding end mill is used, and the rounding amount is R=0.1~0.15m. Reduce the burr of the meshing angle and improve the tooth top intervention during gear transmission. The precision inspection of the front gear machinery and equipment shall be carried out once a year, and maintenance must be carried out if it fails to meet the requirements. The operator should also carry out self-examination frequently. If the measures are not effective, the axial clearance of the lathe spindle should be controlled within 0.01mm, the diameter of the tool shaft should be less than 0.005mm, and the spiral bevel gear will shake less than 0.008mm. The installation accuracy of the CNC blade: the axial vibration of the CNC blade is controlled within 0.003mm, and the inner hole vibration is less than 0.004mm. The accuracy of the front gear work clothes, the gap between the journal diameter and the workpiece hole of the product, ensure that it is within 0.001~0.004mm. The external thread on the journal must be cut by the external thread bed under the precise positioning of the C-top: flatness ≤ 0.003 mm, radial runout ≤ 0.005 mm. The nut must ensure that the thread and the reference point are clamped and turned at one time, and the flatness of the sealing ring is less than or equal to 0.003 mm.
7. Civilized behavior manufacturing
More than 30% of the gear transmission noise comes from burrs, bumps and bumps. Some processing plants remove burrs and bumps and bumps before the gearbox is installed, which is a passive method.
(1) For gear shaft parts, after hobbing, the teeth are immediately covered with a special plastic protective shell, and then transferred to the next process, and the special plastic protective shell is brought into the warehouse and delivered.
(2) Carry out the honing process to reduce the surface roughness of the journal, remove burrs, and avoid bumps and bumps, which can reasonably reduce gear transmission noise.
8. Using other raw materials and heat treatment, metal surface treatment methods
(1) The powder metallurgy forming technology can be used, and the tooth part can be induction hardened after gear forming.
(2) Using ink pig iron, after gear drilling and processing, soft nitriding treatment is carried out.
(3) Using quenched and tempered steel raw materials, after gear drilling work, soft nitriding treatment or tooth electroplating copper is used to solve the problem. To sum up the above, to eliminate gear transmission noise, gear raw materials and heat treatment are essential, gear blank accuracy is ensured, gear accuracy is important, and civilized behavior manufacturing is the foundation.