The technical requirements for sheet metal drawings are generally specified in the technical requirements:
1. Unspecified tolerance requirements
2. Detailed requirements for parts (e.g., deburring)
3. If necessary, the surface treatment method should also be specified.
4. If welding is involved, the treatment of weld beads will also be required. Sheet metal technical requirements include: Materials (the name and specifications of the materials must be specified; some require the national standard code); the thickness and quality of the sheet metal should conform to national standards, and the sheet metal used must be accompanied by a performance test report and manufacturer's certificate. Material appearance: flat, rust-free, without cracks or deformation. Part dimensions: according to the drawings and national standards, with zero defects in important dimensions.
After the rolling bearing is installed, it should rotate flexibly and smoothly by hand. The mating surfaces of the upper and lower bearing shells should fit tightly; a 0.05mm feeler gauge should not be able to penetrate. When fixing bearing bushes with locating pins, drilling, reaming, and pin fitting should be performed while ensuring the bush opening and end face are flush with the opening and closing surfaces and end faces of the relevant bearing holes. The pins must not loosen after being driven in. For spherical bearings, the bearing body and bearing seat should have uniform contact; using a coloring method, the contact area should not be less than 70%. Alloy bearing liners with a yellow surface are not permitted. There should be no separation from the core within the specified contact angle, and the area of separation from the core outside the contact angle should not exceed 10% of the total non-contact area. The reference end face of the gear (worm gear) should fit snugly against the shaft shoulder (or locating sleeve end face), and a 0.05mm feeler gauge should not penetrate. The perpendicularity of the gear reference end face to the axis should also be ensured.
Fasteners requiring a specified tightening torque must be tightened using a torque wrench and to the specified torque. When assembling tapered pins, a coloring inspection should be performed on the contact area with the hole; the contact rate should not be less than 60% of the mating length and should be evenly distributed. The flat key and the keyway on the shaft should have uniform contact on both sides, and there should be no gaps between the mating surfaces. For splines, at least 2/3 of the tooth surfaces should be in contact simultaneously, and the contact rate should not be less than 50% in both the length and height directions of the key teeth. After assembly, sliding fit flat keys (or splines) should move freely without uneven tightness. Excess adhesive should be removed after bonding. There should be no jamming between the bearing outer ring and the semi-circular hole of the open bearing housing and bearing cap.
