What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
new type of screw includes a fixing object and a screw body composed of a nut, a fixing piece and a screw rod. An outer gear ring is fixedly sleeved on the fixing piece, and a support plate is arranged on the lower side of the outer gear ring. The upper side of the support plate is connected with a mounting frame through an adjustment mechanism, the inside of the mounting frame is connected with the outer gear ring through an anti-drop mechanism, and a mounting plate is fixedly connected to the side of the support plate close to the fixed object, and the mounting plate is clamped The coupling mechanism is connected to the fixture.
Type 1 nut refers to an ordinary hexagonal nut with a nominal height of m ≥ 0.8D. Its type and size should meet the requirements of GB/T6170; while the height of type 2 nut is higher than that of type 1 nut, its type and size should comply with GB/T6170. T6175. There are two purposes to increase the type 2 nut: one is to obtain a relatively inexpensive nut that does not require heat treatment by increasing the height of the nut. Because D≤M16 grade 8 type 1 nuts do not need heat treatment, among grade 8 nuts, only the specifications of D>M16~39 use type 2 nuts. Obviously, type 1 nuts that do not need heat treatment cannot reach grade 9 nuts. Mechanical property requirements. Another purpose of specifying Type 2 nuts is to obtain a more ductile grade 12 nut. As the height of the nut increases, the guaranteed stress index can be achieved at a lower quenching and tempering hardness, so the toughness of the nut is increased. Classified by tooth spacing: standard teeth, regular teeth, fine teeth, very fine teeth and cross teeth. Classification by material: stainless steel hexagon nuts and carbon steel hexagon nuts, copper hexagon nuts, iron hexagon nuts. Classification by thickness: hexagonal thick nuts and hexagonal thin nuts. Classification by usage: hot melt copper nut, hot pressed copper nut, embedded copper nut and ultrasonic copper nut
The machinery industry is one of the main users of fasteners. Due to China's late understanding of the important position of mechanical basic parts in the machinery industry and a long-term lack of investment, the entire industry has a poor foundation, weak foundation and weak strength. Especially with the improvement of the level of the main engine in China, the bottleneck phenomenon that the mechanical basic parts lag behind the main engine has become increasingly apparent. Today, although the state has given certain support in technology introduction, technological transformation, scientific research and development, etc., there is still a big gap compared with the current market demand and foreign levels. Unstable quality, high early failure rate and poor reliability. Fasteners are the main basic products in the machinery industry, and the development of the machinery industry also puts forward higher requirements for fastener products. Domestic ordinary standard fasteners have always been in oversupply, while high-end fasteners (high temperature, special-shaped, titanium-plastic composite, special performance and other fasteners) are in short supply, and they also rely on imports. The State Machinery Bureau lists ordinary standard fasteners as restricted development products, and high-strength special-shaped fasteners as currently encouraged development products. With the improvement of the country's industrialization level and technological progress, the use of high-strength fasteners has gradually increased.
The combination screw includes a head, a threaded section and a flanging section, the flanging section is arranged below the threaded section, and the flanging section and the threaded section pass through the mounting holes on the fittings, so that the combination screw and the fittings are rotatably connected, so After the flanging section passes through the fitting, the bottom of the flanging section is riveted and pressed so that the bottom of the flanging section is turned outward, so that the combined screw cannot be separated from the fitting.
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