I. Basic Installation Steps (General)
1. Pre-assembly: First, hand-tighten the nut onto the bolt, ensuring thread alignment and avoiding misalignment.
2. Initial Tightening: Tighten with a wrench or socket wrench until the parts fit snugly.
3. Final Tightening: Tighten to the required torque, or ensure the connection is secure. For connections with torque requirements, always use a torque wrench.
II. Key Scenarios and Techniques
1. Double Nut Locking: After tightening the lower nut, use the upper nut to press the lower nut down to lock it in place and prevent loosening due to vibration.
2. Cotter Pin Fitting: After tightening the nut, align the bolt pin hole, insert the cotter pin, and tighten.
3. Locking Washer Locking: Insert the inner wing of the washer into the threaded groove, tighten the nut, and then bend the outer wing to fit snugly against the side of the nut.
4. Special Locking Nuts (e.g., Nylon Locking Nuts): During installation, rotate the nut along the bolt to the desired position and tighten it firmly with a wrench until the nylon ring creates resistance.
III. Important Precautions
1. Specification Matching: Ensure the nut and bolt thread specifications (e.g., M16) and strength class (e.g., 8.8 grade bolt with 8 grade nut) are completely consistent.
2. Anti-Loosening Verification: After installation, check if the cotter pin is intact and if the locking washer is bent and fitted properly.
3. Regular Inspection: Establish inspection cycles for important connections; increase the inspection frequency in vibrating environments.
4. Avoid Over-Tightening or Over-Loosening: Over-tightening may damage the bolt or nut; under-tightening may cause loosening during operation.
IV. Post-Installation Inspection Points
1. Visual Inspection: Confirm that the anti-loosening markings (e.g., lines) are not misaligned, and that the cotter pin, locking washer, etc., are not displaced or detached.
2. Functional Testing: Use a torque wrench to check if the tightening torque meets the requirements, or simulate vibration in the working environment to check for looseness.
3. Regular Maintenance: For important connections, it is recommended to check monthly or quarterly. Increase the inspection frequency in high-temperature or corrosive environments.
