What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
screw generally includes a screw head, a screw part and a screw tail. In the traditional screw processing, the screw head and the screw part are punched out first, and then the threaded part is processed on the screw shank through the turning process. When the screw head is traditionally punched, the screw head is easily damaged due to the large punching force.
screw is a common threaded connection part, which is mainly used to fix a part on the connection body. When it is necessary to connect, use the screw to pass through the hole on the connected parts, and screw the external thread on the screw into the connecting body to tighten it; The coupling part is separated from the coupling body. Existing common tools for screw disassembly and assembly are generally adjustable wrenches, open-end wrenches, Torx wrenches, socket wrenches, Allen wrenches, flat-blade screwdrivers, cross-shaped screwdrivers, etc., and a screw can only be disassembled with one or one type of tool. Assembly work; when the types of tools are not complete, the screw disassembly and assembly work is difficult to complete, and the screw disassembly and assembly work is greatly limited by the tools.
square nut described by Guangdong Yueluo Hardware Industry Co., Ltd. includes a nut body 1, the nut body 1 is in the shape of a cube, the side length is 7.6mm, and the height is 2.4mm. The upper and lower ends of the nut body 1 are respectively set. There are circular protrusions 2 and circular protrusions 3 with a height of 0.25mm, and the circular protrusions 2 and the circular protrusions 3 are respectively tangent to the upper and lower surfaces of the nut body 1 in a square shape. A through hole 4 is provided in the middle of the shaped protrusion 2 and the circular protrusion 3, and runs through the nut body 1. The opening of the through hole 1 is provided with a chamfer 5 of 30°, and a thread 6 is provided on the inner wall of the through hole 4. , the circular protrusion 2 is provided with a number of strip-shaped protrusions 7 along the circumference inward to the opening of the through hole 4. The number of the strip-shaped protrusions 7 can be arbitrary, and the ideal number is 26, and the through hole 4 is open. There are several strip-shaped grooves 8 at the circumference of the circular protrusion 3. The number of strip-shaped grooves 8 can be arbitrary, and the ideal number is 26. The circular protrusions 2 and the circular protrusions 3 There is a chamfer 9 of 15° extending outward to the prism of the nut body 1 . The production of square nuts described by Guangdong Yueluo Hardware Industry Co., Ltd. is basically the same as the traditional nut process. The key point is to use a punching machine to punch out circular protrusions on both ends. High, and the circular protrusion 2 is punched again to make a bar-shaped protrusion 7, and at this time, the height of the circular protrusion 2 is consistent with the plane height of the circular protrusion 3, and the circular protrusion 3 is formed by stamping. groove 8. The contact surface of the nut body 1 is increased by providing circular protrusions 2 and circular protrusions 3 on the upper and lower end surfaces of the nut body 1, and respectively providing a bar-shaped protrusion 7 and a bar-shaped groove 8 at the two circular protrusions. Therefore, the friction between the nut body 1 and the fastener is effectively increased, and a good fastening effect is achieved.
Now people often use spring washers to lock nuts and bolts, spring washers, generally stainless steel and carbon steel non-closed spiral washers, under the nut, above the flat washer, increase the friction between the nut and the bolt, used to prevent The loosening of the nut plays a role in preventing vibration and loosening, but it is often due to a radial external tension, which is caused by the tightening axial force generated by the tightening torque, and the phenomenon of open ring expansion occurs, and the hydrogen embrittlement of the spring washer often occurs. The pressure is unevenly applied to the flat washer through the spring washer, and the friction coefficient between the spring washer and the nut and the flat washer is small, resulting in vibration, rotation and relaxation.
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