What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
screw is a tool that uses the physical and mathematical principles of the circular rotation and friction of an object to fasten the parts of the object step by step. Since the parts to be fixed are different, different types of screws are required for different applications. Press screw is a new type of fastener applied to thin plate or sheet metal. The principle is to press the embossed teeth into the preset holes of the sheet metal. The diameter of the general preset holes is slightly smaller than the outer diameter of the pressure riveting screw. The periphery of the hole is plastically deformed, and the deformed object is squeezed into the guide groove, thereby producing a locking effect. However, the existing pressing screws are easy to loosen due to long use time or frequent vibrations, which is prone to certain hidden dangers.
It can be seen from the figure that no matter how the screw core swings, it will not fall off from the screw sleeve. This is because part of the bead 5 is stuck in the hole 6 of the screw sleeve 1 and the other part is stuck in the screw core 2. In the groove 8, it plays the role of positioning. If the screw sleeve rotates clockwise, the beads 5 can only slide in the groove 8 of the screw core 2 under the driving of the screw sleeve 1 and cannot drive the screw core 2 to rotate. If the screw sleeve 8 rotates in the opposite direction, the bead 5 will be stuck on the stop 7 of the screw core 2 so as to drive the screw core 2 to rotate.
leak-proof combined gasket relates to a gasket and solves the problem of short service life of the existing gasket. The combined gasket comprises: an O-shaped sealing ring, which is an annular sealing ring with an outer diameter of D and an inner diameter of E. The section diameter is A; the steel outer ring is a steel flat annular outer ring, which is sleeved on the outer surface of the O-ring, the inner diameter is F, and F=D, the thickness is B, B=0.785A ;The steel inner ring is a steel flat annular inner ring, embedded in the inner surface of the O-ring, the outer diameter is G, and G=E; the thickness is C, and C=B. When the O-ring in the combined washer is pressed by the bolt for sealing, it is positioned between the steel outer ring and the steel inner ring, and is protected by both of them, so that the tightening torque of the bolt can be reduced at least Double the sealing performance without reducing the sealing performance, extending the service life of the thread and reducing the production cost.
At present, during assembly of many pin installation mechanisms, the pins need to be installed into the holes or arranged in an orderly manner, and there are many problems in this assembly method. First of all, during assembly, if the hole diameter of the hole product is large, when the pin enters the hole of the hole product, part of the pin entering the hole of the hole product is not fixed, which often leads to slight deviation. In addition, this assembly method is usually only suitable for parts with large apertures and small depths, and when installing multiple pins, it is impossible to automatically install all pins in place due to space constraints. Special tools need to be made for installation operations, and it is easy to cause pins. damage.
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