What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
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. Screw installation names are divided into: machine screws, self-tapping screws, drill-tail screws, wallboard screws, fiberboard screws, wood screws, hexagonal wood screws, non-prolapse screws, combination screws, miniature screws, furniture screws, electronic screws, chain belt screws .
Self-tapping screw is a kind of threaded fastener that self-tapping and drilling the matching female thread in the pre-drilled hole of metal or non-metal material. When using self-tapping screw, a flat washer is often required to protect the fastening surface. Traditional When the self-tapping screw is used, the flat pad is easy to fall off, resulting in low work efficiency. In view of this, we propose a combined structure of the stuck self-tapping screw spring washer that prevents the flat pad from falling off.
The Chinese Patent Application No. 201320368989.2 discloses a pin, which includes a pin body and a cylindrical body part integrally provided with the pin body, a convex tip is provided on the cylindrical body part at one end of the pin body, and the convex The tip is horizontally arranged around the cylindrical body part and protrudes from the surface of the cylindrical body part. The connection between the cylindrical body part and the convex tip is provided with an inclined plane. Although this pin solves the problems of easy loosening and falling off to a certain extent, However, this kind of pin still has the problem of loosening and falling off in the case of bad working conditions and severe vibration.
In general, the size, mechanical properties and working performance requirements of self-tapping screws have the following standards: 1. Self-tapping screw size standard ASME B18.6.3 2010 standard not only introduces the dimensions of slotted and cross-recessed self-tapping screws and metal drive screws, but also includes the mechanical properties and work performance requirements of carbon steel self-tapping screws. The appendix gives instructions for measuring the various dimensions and application guidance on clamping lengths and test apertures. 2. Self-tapping screw performance standards (including mechanical properties and work performance): (1) SAE J933: Introduces the mechanical performance and work performance requirements of carbon steel ordinary self-tapping screws and white-cut self-tapping screws. The requirements for selection of raw materials, heat treatment, depth of carburized layer, surface hardness, and core hardness are further specified. (2) SAE J81: The mechanical properties and working performance of self-extrusion self-tapping screws (self-tapping locking screws) are introduced. (3) SAE J78: The mechanical properties and working properties of self-drilling and self-tapping screws are introduced. (4) IFl-113: The mechanical properties and working properties of self-drilling and self-tapping screws are introduced. (5) ASTM C1513: Introduces the mechanical properties and performance requirements of carbon steel self-tapping screws. For other special types of self-tapping screws, there is no corresponding national or industrial standard, and no data for self-tapping screws made of other metal materials other than carbon steel have been recognized. For technical data on these self-tapping screws, you can check with the manufacturer.
The above content is uploaded by Yueluo or the Internet. If there is any copyright issue, please contact [email protected].
