What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The maximum unscrewing torque of the lock nut is affected by many factors. For the research on the low-cycle fatigue performance of the lock nut, the pitch diameter of the thread, the helix angle and the bevel angle of the thread remain unchanged. Only the maximum elastic restoring force FNmax and the equivalent friction angle ρe of the thread piece will appear to a certain extent after repeated use. Change. Therefore, it is only necessary to analyze the variation law of the maximum unscrewing moment when the lock nut is subjected to cyclic load from these two aspects.
There are two types of bolt detection: manual and machine. Manual is the most primitive and the most commonly used consistent detection method. In order to minimize the outflow of defective products, general production enterprise personnel inspect the packaged or shipped products by visual means to exclude defective products (defects include tooth damage, mixed materials, rust, etc.). [2] Another way is automatic machine inspection, mainly magnetic particle inspection. Magnetic particle inspection is to use the interaction between the leakage magnetic field at the defect of the bolt and the magnetic powder, aiming at the difference between the magnetic permeability of the bolts (such as cracks, slag inclusions, mixed materials, etc.) and the magnetic permeability of steel, these materials are discontinuous after magnetization. The magnetic field at the place will be turbulent, and a leakage magnetic field will be generated on the surface of the workpiece where part of the magnetic flux leaks, thereby attracting the magnetic powder to form the magnetic powder accumulation at the defect—magnetic traces. The accumulation of these magnetic powders is observed and explained, and the purpose of rejecting defective products has been achieved.
A nut is a commonly used fastener, usually combined with a screw to form a set of fastening devices. In order to effectively achieve a more effective tightening effect and prevent a single nut from loosening by itself, two nuts are used together in many places to further increase the tightening effect;
The rivet provided by Yueluo Creation includes a mandrel and a coaxial matching nail sleeve outside the mandrel; the mandrel includes a head, a central rod and a tail, and a position close to the head is provided with an inner A concave section of the lock ring area, a position close to the tail is provided with a section of lock area that inclines and shrinks inward along the direction of the head to the tail; the lock ring area of the core rod is gap-fitted and fixed with a lock ring , a part of the lock ring is located inside the sleeve head of the nail sleeve, and the part of the lock ring located outside the sleeve head of the nail sleeve can be interference fit with the nail sleeve; the nail sleeve The sleeve is provided with a through hole for the core rod to penetrate into, the inner wall of the nail sleeve forming the through hole is provided with a protruding structure, and one end of the protruding structure is close to the sleeve head of the nail sleeve The end of the core rod is close to or adjacent to the end of the tail of the core rod.
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