What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In the production process of Yueluo, according to the different gap guarantee schemes adopted in the mold design, different gap assembly adjustment methods are adopted accordingly. At present, the gasket method, light transmission method, measurement method, copper plating (zinc) method are often used Method, coating method, process allowance, locator positioning and other assembly adjustment methods. Generally speaking, for the working parts processed separately by the punch and the concave die, since the reasonable gap of the die has been formed theoretically, the assembly principle is to fix the working part that is not easy to adjust, and adjust the working part of the other working part. To change the position between the punch and the die to ensure a uniform gap, at this time, only the screws are pre-tightened, and the positioning pins are not fixed. Yueluo, however, many years of practical experience have made those skilled in the art notice that if they can pay attention to the positioning pins and use the positioning pins in a targeted manner in the mold design or manufacturing process, they can often produce miraculous results with half the effort. Therefore, it is very important to design a positioning pin for a specific mold, which is of great practical significance.
Yueluo relates to a self-tapping screw according to the preamble of claim 1. A self-tapping screw is known from EP0623759B1, the ratio of the outer diameter to the smaller diameter of the self-tapping screw is about 1.25-1.5, the ratio of the outer diameter to the pitch lead is about 1.5-1.6 and the thread The flank angles of , are < 50° and ≥ 35°. EP0433484B1 proposes a self-tapping screw whose thread is provided with cutting teeth of approximately arcuate design, and the cutting edge and the thread crest are at the same horizontal position and are set in opposite directions. One purpose of Yueluo is to realize a general type of self-tapping screw so that it can be screwed particularly easily into holes drilled in concrete or other materials such as bricks and the like. According to Yueluo, this object is achieved by the features in the characterizing part of claim 1, and surprisingly, it has been found that the parallel arrangement of the flanks, ie with a flank angle of about 0°, will make screwing particularly easy when screwing in , especially if the diameter of the hole varies within an allowable tolerance. One reason may be due to the fact that there is no lateral pressure on the material screwed into the thread, even if threads of different depths are cut in concrete or other materials such as brick, chipped plywood, or hardwood. The thread cuts into the material over its entire width by cutting grooves. In particular according to the embodiment of claim 4 the material cut out when screwing in the screw can be discharged without any accumulation, the dependent claims reflecting many advantages of further embodiments.
screw is a tool that uses the physical and mathematical principles of the circular rotation and friction of an object to fasten the mechanism of the object step by step. A screw is a common term for fasteners, an everyday colloquial language. Screws are indispensable industrial necessities in daily life: tiny screws used in cameras, glasses, clocks, electronics, etc.; general screws in televisions, electrical products, musical instruments, furniture, etc.; as for engineering, construction, and bridges, large screws are used. Screws and nuts; transportation equipment, airplanes, trams, automobiles, etc. are used together with large and small screws. Screws have important tasks in industry. As long as there is industry on earth, the function of screws will always be important. The screw is a common invention in people's production and life for thousands of years. According to the application field, it is the first invention of mankind.
Today's advanced manufacturing represented by large aircraft, large power generation equipment, automobiles, high-speed trains, large ships, and large complete sets of equipment has entered an important development direction. As a result, fasteners will enter an important stage of development. High-strength bolts are used for the connection of important machinery, and repeated disassembly or various installation torque methods require extremely high-strength bolts. Therefore, the quality of its surface condition and thread accuracy will directly affect the service life and safety of the host. In order to improve the friction coefficient and avoid corrosion, seizure or sticking during use, the technical requirements stipulate that the surface should be treated with nickel phosphorus plating. The thickness of the coating is guaranteed to be within the range of 0.02 to 0.03 mm, and the coating is uniform, dense, and free of pinholes.
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