Mechanical non-standard parts processing technology standard

General technical requirements
 
　　 1. Remove oxide scale from parts.
 
　　 2. On the processed surface of the part, there should be no scratches, abrasions and other defects that damage the surface of the part.
 
　　3. Remove burr and flash.
 
　　 Non-standard parts processing and heat treatment requirements
 
　　 1. After quenching and tempering, HRC50～55.
 
　　 2. The parts are subjected to high frequency quenching, tempered at 350～370℃, HRC40～45.
 
　　 3. The carburizing depth is 0.3mm.
 
　　4. Carry out high temperature aging treatment.
 
　　Tolerance requirements
 
　　1. Unmarked shape tolerances should meet the requirements of GB1184-80.
 
　　2. The allowable deviation of the unmarked length dimension is ±0.5mm.
 
　　 3. The casting tolerance zone is symmetrical to the basic size configuration of the rough casting.
 
　　Non-standard machining parts edges and corners
 
　　 1. No fillet radius R5 is noted.
 
　　2. All unfilled chamfers are 2×45°.
 
　　3. Sharp corners/sharp corners/sharp edges are blunt.
 
　　 Non-standard parts processing and assembly requirements
 
　　 1. Each seal must be soaked in oil before assembly.
 
　　 2. Assemble rolling bearings, it is allowed to use oil heating for hot charging, and the oil temperature should not exceed 100℃.
 
　　3. After the gear is assembled, the contact spots and backlash of the tooth surface should meet the requirements of GB10095 and GB11365.
 
　　4. When assembling the hydraulic system, it is allowed to use seal packing or sealant, but it should be prevented from entering the system.
 
　　 5. The parts and components (including purchased parts and outsourcing parts) that enter the assembly must have the certificate of the inspection department before they can be assembled.
 
　　6. ​​The parts must be cleaned up and cleaned before assembling. There should be no burrs, flashes, oxide scales, rust, chips, oil stains, colorants and dust.
 
　　7. The main matching dimensions of parts and components, especially the interference fit dimensions and related accuracy, should be reviewed before assembly.
 
　　 8. The parts are not allowed to knock, bump, scratch and rust during the assembly process.
 
　　 9. When tightening screws, bolts and nuts, it is strictly prohibited to strike or use inappropriate screwdrivers and wrenches. The screw grooves, nuts and screws, and bolt heads shall not be damaged after tightening.
 
　　 10. Fasteners with specified tightening torque must be tightened with a torque wrench and tightened according to the specified tightening torque.
 
　　11. When the same part is fastened with multiple screws (bolts), the screws (bolts) must be tightened crosswise, symmetrically, gradually and evenly.
 
　　 12. When assembling the tapered pin, the hole should be painted and checked, and the contact rate should not be less than 60% of the mating length, and should be evenly distributed.
 
　　 13. The flat key should be evenly in contact with the two sides of the keyway on the shaft, and there should be no gap between the mating surfaces.
 
　　14. The number of tooth surfaces contacted by the spline assembly at the same time shall not be less than 2/3, and the contact rate shall not be less than 50% in the direction of the length and height of the key teeth.
 
　　 15. After the sliding-fit flat key (or spline) is assembled, the relative parts can move freely without unevenness of tightness.
 
　　 16. After bonding, the excess adhesive should be removed.
 
　　17. The semicircular holes of the bearing outer ring and the open bearing seat and bearing cover are not allowed to jam.
 
18. The outer ring of the bearing should be in good contact with the semicircular hole of the open bearing seat and the bearing cover. When checking with coloring, it should be symmetrical with the bearing seat at 120° to the centerline and with the bearing cap within the range of 90° symmetrical to the centerline. Even contact. When checking with a feeler gauge within the above range, the 0.03mm feeler gauge shall not be inserted into 1/3 of the outer ring width.
 
　　 19. After assembly, the outer ring of the bearing should contact the end face of the bearing cap at the positioning end evenly.
 
　　20. After the rolling bearing is installed, it should be turned flexibly and smoothly by hand.
 
　　21. The joint surfaces of the upper and lower bearing bushes should be closely attached, and they cannot be checked with a 0.05mm feeler gauge.
 
　　22. When fixing the bearing bush with positioning pins, drill the reaming and matching pins while ensuring that the opening and closing faces and end breads of the bushing surface and end face of the relevant bearing hole are flush with each other. Do not loosen the pin after driving in.
 
　　23. The bearing body of the spherical bearing and the bearing seat should be in uniform contact, and the contact should not be less than 70% when inspected by the coloring method.
 
　　24. The alloy bearing lining surface is not allowed to be used when the surface is yellow, and the nucleation is not allowed within the specified contact angle, and the nucleation area outside the contact angle shall not be greater than 10% of the total area of ​​the non-contact area.
 
　　 25. The reference end face of the gear (worm gear) and the shaft shoulder (or the end face of the positioning sleeve) should fit together and cannot be checked with a 0.05mm feeler gauge. And should ensure the verticality requirements of the reference end face of the gear and the axis.
 
　　 26. The joint surface of the gear box and the cover should be in good contact.
 
　　27. Strictly check and remove the sharp corners, burrs and foreign objects remaining during the processing of the parts before assembly. Ensure that the seal is not scratched when it is installed.