What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Fig. 1, Fig. 2, and Fig. 3 show that the rivet nut is cut into the required blank from a chemically treated low carbon steel disc, and the blank is placed in the die, and the upper and lower punches are used for shaping to obtain a shaped blank. , and then put the shaped blank in the die, use the punch punch to cold-head out the required brim blank (1) and the deformed skirt (2), and then use the punch punch in the die to continue Cold heading out the brim blank (1) and the deformed skirt (2). Then put the semi-finished material into the concave die and use the punch of the punch to continue to squeeze the threaded hole (3) of the nut tapping skirt, and then put the semi-finished blank into the concave die and use the upper punch and the lower sleeve to drop it. material. There are fish teeth (6) below the brim; the outer side of the lower end of the threaded hole is provided with a chamfer (5); the cross-section of the thread of the inner wall of the threaded hole is an isosceles trapezoid, and the upper bottom of the trapezoid is a concave arc (4), In this way, the riveted object is firmly connected to the rivet nut.
In the process of driving the car, it is inevitable to use the brake frequently, which will cause the gap between the brake drum and the friction pad of the car to become larger. Therefore, it needs to be adjusted in time, otherwise, the hidden danger of unsafe driving will be buried due to the excessive braking distance and the out-of-round brake drum. Therefore, motor vehicles must be equipped with automatic adjustment arms. In the existing automatic adjustment arm, the worm inside the housing is limited by the spring pad, the spring and the spring cover, and the end face of the spring pad is directly in contact with the worm, and the rotation of the worm is inflexible due to frictional resistance during rotation.
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.
A screw suitable for a variety of tools is a single-structure threaded part, including a screw body and a screw head. The outer surface of the screw body is processed with an external thread 1, and the outer side of the screw head is formed by six screw heads. Prismatic, the top surface of each edge of the outer hexagonal prism is a boss, between each boss is an end face groove 4, and the middle of each boss is provided with an end face hole 3; the inner side of the screw head is formed by six screw heads. The side surface 5 forms an inner hexagonal prism hole, and the bottom of the inner hexagonal prism hole is processed with a cross groove 10 .
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