1. Assembly process

The description of torque in the process is uniformly expressed in Nm.

The assembly torque and its accuracy level should be explained in the process flowchart or work instruction manual.

The process document preparation department can improve the accuracy level of assembly torque according to the actual assembly situation.

The pre tightening steps for torque points that require the use of a fixed torque wrench for re tightening must be indicated in the key element column of the work instruction manual.

For the re tightening steps of torque points that require the use of a fixed torque wrench, it must be noted in the key element column of the operation manual: if the rotation angle of the fixed torque wrench is less than 45 degrees and a "click" sound is emitted, the nut must be loosened and re tightened.

For the tightening steps of torque points with C-level accuracy, it is necessary to indicate in the key element column of the operation manual: ensure that the screws are tightened and there is no slippage phenomenon. Note: ① Fill in this section based on the actual tool used, ② Fill in this section based on the actual threaded fasteners used, such as screws, bolts, or nuts. ③ Fill in here based on the actual status of the threaded fasteners used, such as installation surfaces, flat washers, or elastic washers.

2. Assembly process

All threaded fasteners with A-grade and B-grade accuracy must be tightened using a fixed torque tool.

C-grade precision threaded fasteners can be tightened using non fixed torque tools, but there must be no looseness or slippage.

The fixed torque tools used in the production process and repair process must be preset fixed torque tools.

When using a fixed torque tool for assembly, the angle between the axis of the sleeve and the axis of the threaded fastener in any direction is less than 5 °.

When using a fixed torque wrench for assembly, place your hand in the effective position of the handle and apply force smoothly. The angle of force application should be perpendicular to the force arm within the rotation plane of the force arm. The deviation of the above force application angles in any direction should not exceed 15 °.

When using an open end torque wrench for assembly, bolts or nuts should be placed at the bottom of the open end.

During the assembly process, it is necessary to use screwdrivers that match the specifications of bolts and nuts (such as sleeves, openings, crossheads, star heads, hexagons, etc.). During assembly, if the fixed torque tool does not rotate or the rotation angle is less than 45 ° to reach the preset torque, the threaded fasteners must be loosened and re tightened.

Unless otherwise specified in the process documents, the torque for pre tightening threaded fasteners shall not exceed 80% of the target torque value.