What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The force condition of the screw is broadcasted: 1) Self-weight G; 2) Torque M required to overcome material resistance; 3) Axial force P generated by material pressure. Screw screw screw is generally scrapped due to long-term wear, the gap between the screw and the barrel is too large and cannot be extruded normally, but there are also examples of damage due to improper design or improper operation. Therefore, the screw should also meet certain strength requirements. 4) The dangerous section of the screw is generally at the smallest thread root diameter in the feeding section. According to material mechanics, for plastic materials, the composite stress is calculated by the third strength theory, and its strength conditions are:
The profile of the American National thread (60 profile angle and H/8 flatness) is different from the Wyeth thread profile (55 profile angle and H/6 flattening height). American National Thread is widely used in regions and industries that are influenced by American industry. In World War II, due to the inconsistent thread standards used by the Allies, the logistical supply difficulties caused serious economic losses and casualties to the Allies. Immediately after the end of World War II, the United States, the United Kingdom, Canada and other allies immediately began to formulate a unified thread standard among allied countries, and promulgated a unified thread standard in 1948. Because the economic strength and military strength of the United States dominated the Allied forces at that time, the unified thread was mainly formulated according to the national thread standard of the United States. Unity; the latter letter N is derived from the N designation for American National Threads. Since then, the unified thread began to squeeze the original use market of the British Whitworth thread.
The flange nut and the general hexagon nut are basically the same in size and thread specification, but compared with the hexagon nut, the gasket and the nut are integrated, and there are anti-skid tooth patterns on the bottom, which increases the nut and the workpiece. Compared with the combination of ordinary nut and washer, it is stronger and has greater tensile force. In some equipment with large vibration amplitude, due to the action of huge vibration force, the flange nut is prone to loosening, which often occurs. If the flange nut falls off the equipment or even damages, the staff also needs to install the flange nut repeatedly, which increases the labor intensity and brings great inconvenience to the use. Now a split type tightening nut is proposed.
The purpose of Guangdong Yueluo Hardware Industry Co., Ltd. is to provide a flat gasket that improves the lubrication performance of the contact surface and reduces the friction of the contact surface. Yueluo is implemented through the following technical solutions: a flat gasket with straight upper and lower end faces, characterized in that: the upper and lower end faces are dotted with pits, the pits are spherical pits, and the pit diameter is 2-3mm , the pit depth is between 0.5-lmm. The bottoms of some of the pits are provided with through holes penetrating the upper and lower end faces, and the diameter of the through holes is not greater than 0.5mm. The flat gaskets provided by Yueluo have pits with reasonable design parameters on the upper and lower end faces of the flat gaskets. The pits can store oil, so the lubrication of the contact surfaces of the gaskets can be well improved. It can effectively reduce the friction of the contact surface of the gasket and reduce the failure rate; in addition, the design of the through hole enables a smooth oil passage between the upper and lower end faces of the gasket, ensuring that the upper and lower end faces can be well lubricated.
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