Service HotlineIn the automobile industry, it is often necessary to install bolts at the opening of a closed cavity to fix and connect other parts. However, the diameter of the opening of the closed cavity is often larger than that of the head of the bolt, so it is necessary to set a strip-shaped spacer on the head of the bolt, so that the spacer can penetrate the opening longitudinally, and then block the opening horizontally, so as to be stuck with an upside-down buckle. Bolt head. However, since the bolt body of the bolt has a certain length, the manual vertical and horizontal turning operation after the strip spacer penetrates the opening is very difficult, and it is easy to drop the bolt and the spacer into the airtight cavity together, which greatly increases the assembly time. Increased labor costs.
Two combination screws are also called two combination screws. As the name suggests, it consists of a screw with a spring washer or only a flat washer. After the thread rolling, the two components are combined together. Two combination screws are available in iron and stainless steel. For iron, there are screw materials such as screw wire 1010, 1018, 10B21, etc. The general iron pier needs to be electroplated, and electroplating is divided into environmental protection and ordinary. For example, there are environmentally friendly color zinc, environmentally friendly blue zinc, white zinc, color zinc, white nickel and other electroplating. Stainless steel two combination screws. The material is stainless steel 304.
Commonly used screw materials in my country are No. 45 steel, 40Cr, ammoniated steel, 38CrMOAl, superalloy, etc. 1) No. 45 steel is cheap and has good processing performance, but poor wear resistance and corrosion resistance. Heat treatment: quenched and tempered HB220-270, high-frequency quenched HRC45--48. 2) The performance of 40Cr is better than that of No. 45 steel, but it is often plated with a layer of chromium to improve its corrosion resistance and wear resistance. However, the requirements for the chrome plating layer are relatively high. If the plating layer is too thin, it is easy to wear, and if it is too thick, it is easy to peel off. After peeling off, it will accelerate the corrosion, and it has been rarely used. Heat treatment: quenched and tempered HB220—270, hard chrome plated HRC>553) nitrided steel, 38CrMoAl have excellent comprehensive properties and are widely used. Generally, the nitride layer reaches 0.4-0.6 mm. However, this material has low resistance to hydrogen chloride corrosion and is relatively expensive. 4) The superalloy material is superior to other materials. This material does not need coating, and is mainly used for the raw halogen-free screw of injection molding machine. The material has high oxidation resistance and corrosion resistance.
The screw is usually installed in the threaded hole of the part, and its main function is to fix the relative position between the two parts. It is widely used in various industries. A traditional screw generally includes a screw rod and a head located at one end of the screw rod. During installation, the screw rod is connected with a threaded hole, and the head is located outside the screw hole and abuts on the edge of the screw hole.
Some heavy equipment such as large motors, large reducers, etc., in order to facilitate the installation and adjustment of equipment and the need for maintenance space, a certain position needs to be moved during equipment installation and maintenance. Usually, a steel base or platform is set under the equipment, and the base or The platform is provided with an oblong bolt installation slot, commonly known as an oblong slot, as shown in Figure 1--Figure 4. When using common hexagon head bolts or common T-bolts with the long circular groove in Figures 1 and 2, auxiliary fixing bolts or welding stoppers are required on the back of the long circular groove to prevent the bolt from rotating when the nut is tightened. In Fig. 3 and Fig. 4, the long circular groove itself has a clamping groove to prevent the rotation of the bolt, but this structure greatly increases the processing cost of the long circular groove.
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