Fastener Knowledge | Threaded Connection Assembly Knowledge
Oct 18, 2022
Screw connection is a kind of practical removable fixed connection, which has the advantages of simple structure, reliable connection, convenient assembly and disassembly, and is widely used in mechanical equipment.
一、 Assembly of stud bolts
Fig. 1 Fixing Form of Stud Bolts
1. In order to prevent the bolt from locking when screwing in, and to facilitate removal and repeated installation, the stud bolt can be coated with lubricating oil.
2. The axis of the stud bolt must be perpendicular to the body surface. During installation, use a square ruler to check. If the axis is slightly inclined to the surface of the machine body, use a tap to correct the threaded hole, or use the installed stud to correct; If the inclination is large, do not force correction to prevent the reliability of bolted connection from being damaged.
3. Ensure that the connection between bolts and engine body is tight enough.
4. Common methods for screwing in stud bolts:
① Screw in with two nuts. As shown in Fig. 2a), lock the two nuts on the stud, and then pull the upper nut to screw the stud into the screw hole.
② Screw in with a long nut. As shown in Fig. 2b), the upper screw is used to prevent the relative rotation between the long nut and the stud, and then pull the long nut, and the stud can be screwed in. Loosen the stop screw to remove the long nut.
Fig. 2 Method of screwing in stud bolts
③ Screw in with special tool. The figure shows the special tool for screwing in the stud. The three rollers are placed in the cavity of the tool body, and their circumferential and axial positions are determined by the limit sleeve 4. The limit sleeve is fixed by the groove retainer ring, and the loosening and clamping of the roller are controlled by the inner cavity curve of the tool body. The roller shall be clamped on the polished rod of the bolt, and the stud can be screwed in by turning the tool body in the direction of the arrow as shown in Figure 3, otherwise the bolt can be loosened. The groove curve direction of the tool for removing stud bolts shall be opposite to that of the tool for screwing in.
Fig. 3 Special Tools for Stud Screw in
1. The fitting surface between the nut or screw and the fastener shall be smooth and flat to avoid additional bending moment during tightening.
2. The tightening torque shall be strictly controlled. Excessive tightening torque will stretch or even break the bolt or screw, or cause deformation of the connected parts. When the tightening force is insufficient, the connection is easy to loosen, affecting the reliability.
3. After the nut is tightened, the spring washer shall contact with the nut and the surface of the connected piece on the entire circumference. The length of thread exposed outside the nut shall not be less than two threads, but shall not be too long, generally 3~5mm.
4. When tightening the group nuts, they must be tightened in a certain order, step by step, or the bolts and the machine body will be deformed due to uneven stress. When tightening the group nuts with rectangular arrangement, start from the middle and gradually expand to both sides, as shown in Figure 4. When tightening round or square arranged group nuts, they must be tightened symmetrically, as shown in Figure 5.
Fig. 4 Sequence of tightening group nuts in rectangular arrangement
Fig. 5 Sequence of tightening round or square arranged group nuts
For Jinrui, whether you are a fastener demander/dealer/supplier, you can visit the official website of Jinrui for more information: https://www.jinruibolt.com/
Part of Jinrui's product display
Jiangsu Jinrui Metal Products Co., Ltd. is the production base of Shanghai Jinrui standard parts. The factory covers an area of more than 20000 square meters, with a registered capital of 50 million yuan, a total investment of more than 100 million yuan, and an annual output of more than 20000 tons. Its products are exported to more than 40 countries.
Since its establishment in 2001, Jinrui Company has developed into a new layout with Hai'an in Jiangsu as its production base and Baoshan in Shanghai and Nanyang in Henan as its sales centers after more than 20 years of unremitting efforts.
At present, Jinrui's main products include the following six categories:
1. The main products of bolts include metric and American round head oval neck bolts (also called fishtail bolts), internal and external hexagon bolts, hexagon flange bolts, carriage bolts, wheel hub bolts, etc
2. Stud products: full thread thread, double head studs, etc
3. Nut products: hexagon nut, flange nut, heavy nut, square nut, butterfly nut, etc
4. Screw products: self tapping screws, self tapping self drilling screws, wood screws, various machine screws, etc
5. Washer products: flat washer, spring washer, square washer, lock washer, etc
6. Fastener related non-standard products
The wire drawing plant under Jinrui Company also provides processing services such as fine drawing, rough drawing and spheroidizing of wire rods, and supplies finished wire rods of various domestic famous steel mills.
Adhering to the business philosophy of "pioneering and innovating, pursuing excellence", Jinrui has successively introduced multiple types of heading and forming machines, thread rolling machines, nut machines, hot heading and rolling machines, lathes, large hot heading machines and their supporting testing equipment, such as magnetic particle flaw detectors, metallographic analyzers, salt spray testing machines, direct reading spectrometers and optical screening machines, tensile machines, Vickers hardness meters, Rockwell hardness meters, etc., and has set up independent research and development departments, It can produce all kinds of high-quality fasteners such as GB, DIN, ANSI, JIS and ISO international standards. The products are widely used in petroleum, chemical industry, boiler, wind power generation, highway guardrail board, elevator guide rail, machinery manufacturing, construction sites, auto parts, medical equipment and other fields.
Jinrui has been developing vigorously since its establishment. It integrates the advantages of each company, carefully designs and strictly selects materials to make the products more durable, and is highly praised by the majority of users. Jinrui won the ISO9001: 2000 international quality system certification in 2001, the special equipment manufacturing license in 2010, and the TS16949 automobile quality management system certification in 2012. The People's Insurance Company of China underwrites the "Global Product Liability Insurance" for its products, ensuring that every screw can be used with confidence, determination, and peace of mind!
Whether now or in the future, Jinrui will always adhere to the core service concept of "quality first, science and technology to revitalize enterprises, users first, and considerate service", sincerely provide you with high-quality services and high-quality products, and Jinrui will also become your most loyal long-term partner.
