What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
1. When the main body is large equipment, accessories need to be installed, such as sight glass, mechanical seal seat, deceleration frame, etc. At this time, a stud bolt is used, one end is screwed into the main body, and the other end is equipped with a nut after the accessory is installed. Since the accessory is often disassembled, the thread will be worn or damaged, and it is very convenient to use the stud bolt to replace. 2. When the thickness of the connecting body is very large and the bolt length is very long, stud bolts will be used. 3. It is used to connect thick plates and places where it is inconvenient to use hexagonal bolts, such as concrete roof trusses, roof beam suspension monorail beam suspension parts, etc.
In steelmaking plants, the wheels of metallurgical casting crane trolleys used for hanging liquid metal are connected with cardan shafts through flanges. Usually, a keyway is set in the radial direction of the connecting flange, and the keyway is a through groove. The B-type flat key is set in the keyway to transmit torque. During the frequent forward and reverse motion of the wheel, the flange connection bolts are easily loosened. Since the keyway is a through groove, the B-type flat key is easily caused when the flange connection bolts are loosened. It falls off from the keyway of the connecting flange and cannot transmit the torque, which seriously affects the working efficiency of the locomotive. In addition, because the B-type flat key falls off and cannot transmit the torque, the locomotive can only rely on the connecting bolt to transmit the torque when it continues to work. Poor, it is easy to damage and scrap the connecting bolts, and then damage the connecting flanges, requiring frequent replacement and maintenance, high cost, and difficult maintenance.
The existing nut fasteners are generally used to fix the bolts to fix the devices with holes. However, during the operation of most devices, the bolts and nuts are easily loosened and separated due to mechanical vibration, causing long-term vibration. It will cause the nut to separate from the bolt, affecting the safety and stability of the device during operation. At the same time, in the connection between the bolt and the nut for a long time, the external dust easily enters the connection, resulting in the accumulation of dust, making the bolt and nut difficult to disassemble. Affect the use of fasteners.
screw with a gasket includes a screw head and a screw connection part connected with the screw head, the screw connection part is provided with a thread, and a transition part is provided between the screw head and the thread provided on the screw connection part , the diameter of the transition part is smaller than the diameter of the thread, the transition part is sleeved with a plastic washer, the inner ring of the plastic washer is a polygon, and the diameter of the inscribed circle of the inner ring of the plastic washer is smaller than the diameter of the thread. The utility model replaces the traditional metal washer with a plastic washer, which avoids the phenomenon that the washer causes wear on the connection base. The inner hole of the plastic washer adopts a polygonal design, and the diameter of the inscribed circle of the inner ring of the plastic washer is smaller than the diameter of the thread, which is in the same shape as the thread. The multi-point contact solves the problem that the washer is easy to slip off due to the circular design of the inner hole of the traditional metal washer, and improves the assembly efficiency of the screw.
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