1. Head -shaped structure

The main functions of the bolts head or screw head are carrier and wresting, which are mainly divided into hexagonal heads, double hexagonal heads, flower keys, plate heads, sediment, stigma and other head shapes.

2. Wire structure

The twisting structure of the bolts and screws is divided into the outer tie structure and the inner wrestleling structure. The outer tie structure forms mainly include hexagonal heads, duodena heads, flower keys, ten -horn heads, octagonal heads, square heads, moon corners First -class, the hexagonal head and the twelve corner head are commonly used external tie structures, which are very common; the inner tinning structure is mainly used for the head shape of the head, such as the head, the plate, and the cylinder. The structure of the tiered structure is one -word groove, cross slot, inner hexagonal, inner six flowers, etc., as well as foreign patented slot types -high -torque cross slot and high -torque.

Under normal circumstances, the twisting performance of the outer tinning structure is better than the inner tinning structure, so the tissue structure of the high -intensity product is generally used to use the external tie structure, but the installation space required for the external tie structure is greater than the inside wiping twisting. Structure has certain restrictions on the assembly environment. In the inner tinning structure, the twisting performance of the two structures of the inner hexagonal and inner Liuhua is significantly better than that of other inner wiping structures, so it can also be applied to high -strength products; The drilling hole is cut and cut into the six -square punch.

It may fall off and form excess objects. Therefore, it should be removed if there are control requirements for excess objects.

3. Polar structure

The bolt's pole structure refers to the part -free light rod part, which is divided according to its diameter, mainly large diameter rods, middle diameter rods, step -shaped rods and enlarged rods. Large diameter rods are also called standard rods. The nominal diameter is equal to the nominal diameter of the thread. There are two types of diameter tolerances. One is pine publicity, mainly used for h12, H14; Used for anti -shear bolts, such as F9, F7, R6; medium diameter rods are also called fine rods. Its nominal diameter is equal to the middle diameter of the thread. Type bolt; step -shaped rods are also called lumbar rods. Its rod diameter is less than or or equivalent to threaded trails. It is mainly used to reduce the bolt that requires rigidity or requires reducing the bolt of the screw stress concentration. , Its rod diameter is larger than the thread's large diameter, which can form a surgery with the assembly hole, or it can also be used for structural maintenance.

4. Thread structure

The thread structure includes thread length, thread accuracy, threading tooth shape, threaded bottom arc arc and thread tail and shoulder distance.

In the same product standard, the screw length of the bolts of the same diameter specifications is generally fixed value. The increase in the total length of the bolt is mainly reflected in the increase of the bolt bolt length. The screw length of the bolt can be divided into long threads, medium threads and short threads. Long threads are usually suitable for tensile bolts, which are mainly used to bear larger tensile force; short threads are usually suitable for shear bolts, mainly used for connection, defense and falling, not tolerated tensile or small tensile force; medium threads are usually applicable The bolt of the bolt of the composite load can bear a certain tensile force.