What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The conventional auger bit structure 1 includes a rod body 11, a screw head 12 provided on one end of the rod body 11, a drill tail 13 provided on the other end of the rod body 11, and a plurality of threads 14 arranged around the rod body 11; Wherein, the periphery of the drill tail 13 defines a parting line 15, and the parting line 15 makes the drill tail 13 symmetrically divided into a side 131 and a side 132, and a cutting end 133 is formed at the junction of the end of the side 131 and the end of the side 132, respectively. The cutting end 133 is concavely provided with a quarter-turn chip flute 134 in the same direction of the helix, and the edge 132 continues the chip flute 134 and has a quarter-turn chip flute 135 with different helical curvatures. , by connecting the chip groove 134 and the chip groove 135 through different helical curvatures, the drill tail 13 can form a symmetrical and complete chip groove of 188 degrees.
Generally known bolts refer to screws with a larger diameter. According to this statement, the diameter of screws is much smaller than that of bolts. Stud bolts do not have a head, and some are called studs. Both ends of the stud are threaded, with no thread in the middle and a smooth rod in the middle. Studs are used on large equipment such as gear racks. In actual use, the external load will have vibration and the influence of temperature will reduce the frictional force, and the threaded connection will loosen and fail over time. Therefore, it is necessary to do a good job in the maintenance of the stud bolts at ordinary times. Stud bolts or anchor bolts will have problems under the action of mechanical friction for a long time. When problems occur, the engine oil pan should be removed, and the use of the engine bearing bushes should be carefully checked, and the clearance between the bearing bushes should be checked. Whether it is too large, if the gap is too large, it should be replaced in time. When replacing the stud bolts, also replace the connecting rod bolts. When some large equipment such as nail making machines are in normal operation, if they find that the engine is not running very stable or there is abnormal noise, they should stop and check in time to avoid bigger problems.
Self-tapping screw is a kind of threaded fastener that self-tapping and drilling the matching female thread in the pre-drilled hole of metal or non-metal material. When using self-tapping screw, a flat washer is often required to protect the fastening surface. Traditional When the self-tapping screw is used, the flat pad is easy to fall off, resulting in low work efficiency. In view of this, we propose a combined structure of the stuck self-tapping screw spring washer that prevents the flat pad from falling off.
The spring washer usually includes a washer body and a raised claw head punched and formed on the washer body. The spring washer is often placed between the bolt head of the bolt and the connected parts, wherein the raised claw head is connected to the part to be connected. The surfaces of the connecting parts are in contact, and the plane on the gasket body, opposite to the lifting direction of the raised claw head, is in contact with the bolt head. After the bolt head is tightened, the elastic reaction force generated by the raised claw head after flattening makes the The screwed threads are pressed tightly, and at the same time, the raised claw head is pressed against the bolt head and the supporting surface of the connected parts, which has the effect of preventing loosening. However, the traditional spring washer is a single-claw type. When tightening, the raised claw head will cause great damage to the surface of the connected parts, so it is not suitable for the anti-loosening treatment of parts with small surface hardness.
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