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.
self-locking nut is a nut that can self-lock by friction. The general nut will loosen itself due to vibration and other reasons during use. In order to prevent this phenomenon, the self-locking nut was invented. The main functions of self-locking nuts are anti-loose and anti-vibration. For special occasions. Its working principle is generally self-locking by friction. The types of self-locking nuts classified by function include those with nylon rings, those with neck closures, and those with metal anti-loosening devices. They are all effective torque type lock nuts (see GB/T3098.9-2002 national standard).
The screw refers to the screw (foreign name: Screw), which is a tool that uses the physical and mathematical principles of the oblique circular rotation of the object and the frictional force to gradually fasten the utensils and parts. A screw is a common term for fasteners, an everyday colloquial language. Metric threads are measured in MM (millimeters) and have a cusp angle of 60 degrees. Both US and Imperial threads are measured in inches. The cusp angle of the American thread is also 60 degrees, while the cusp angle of the imperial thread is 55 degrees.
On the other hand, especially in the aerospace field, the requirements for the sealing effect of screws are extremely strict, and the traditional screws are directly tightened when screwed into the workpiece or equipment, and the sealing effect is determined by the tightness, but due to the machining error of the workpiece or equipment The direct butt seal between the seals is difficult to achieve.
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