What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
1. Material strain hardening When the material is cyclically loaded, the phenomenon of cyclic strain hardening or cyclic strain softening will occur, that is, under the condition of constant cyclic strain, the stress amplitude will increase or decrease with the increase of the number of cycles. . After several cycles, the stress amplitude enters a cyclic steady state. The low-cycle fatigue of the lock nut is carried out under the condition that the strain is constant, and the strain hardening or softening of the threaded piece will affect the size of its maximum unscrewing torque. The alloy steel used to make the lock nut is a cyclic strain hardening material, and the hardening of the material will increase the elastic restoring force FN of the threaded sheet and increase the unscrewing torque.
A hand screw is a screw with a plastic head, and the user fixes the hand screw by turning the plastic head by hand. At present, a hand screw is disclosed in the market publication number CN202203253U, which includes a plastic head and a screw rod, the plastic head and the screw rod are connected together, and the height of the plastic head is higher than that of an ordinary screw, and the height is 13 cm. The screw of the hand screw is fixed in the plastic head by glue. After a period of use, the aging of the glue leads to the loosening of the screw and the plastic head. When the plastic head is stressed, the screw rod comes out of the plastic head, which affects the normal use of the hand screw.
However, Yueluo still feels that there should be room for improvement for the screw improvement and screw that integrates stability, labor, fast and multi-function in the above two cases; for example, No. 556784 screw improvement Although the rod has the function of cutting and collecting chips, when the screw starts to screw into the object such as wood, it is hindered by the hardness of the object's tissue, so the staff still needs to exert considerable force, resulting in the lock. In the solid operation, there is still a lack of difficulty in screw-in operation; another example, new cases such as No. 289417 screw that integrates locking, stability, labor-saving, fast and multi-function, although the rod has the structural function of cutting and chip removal, it is The rod part is screwed into the middle section to the rear section of the object. Since the debris cannot be discharged, the rod part pushes the outer part of the object to the surrounding tissue of the object, so that the object expands outwards and even seriously damages the appearance of the object.
Further, the clamping mechanism includes two clamping plates placed between the two fixing blocks, a bearing seat is installed on one side of each of the clamping plates, a bearing is installed inside the bearing seat, and the bearing is The inner ring is snap-connected with an elastic adjustment screw, and the other end of the elastic adjustment screw penetrates the fixing block and is placed outside the fixing block.
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