DEVELOPING STUDENTS' KNOWLEDGE AND SKILLS ABOUT JOINTS IN TECHNOLOGY LESSONS

Аннотация

The article describes the types of separable and non-separable joints that contribute to the formation and improvement of students' technological and polytechnical knowledge, as well as theirfields ofapplication. Keywords: Separable and non-separable joints; butt, lap, and corner welds; single-row, multi- row, staggered rivet joints; triangular, rectangular, and metric threaded joints; prismatic, cylindrical, and segmental key joints. In mechanical engineering, various parts are joined together during the assembly of mechanisms and machines, forming either separable or non-separable joints. Separable joints can be disassembled without damaging the parts. Among them, threaded joints are the most common and are classified as bolts and studs. These serve both fastening and sealing purposes. Thread shapes can be triangular, rectangular, or trapezoidal. In simple fastening threaded joints, a bolt or screw is inserted into a hole with a specified clearance. In sealing joints, bolts are driven in tightly. To prevent loosening, locknuts and washers are used. Key and spline joints are used to connect rotating parts on shafts or axles. Keys come in prismatic, cylindrical, and segmental forms and are selected based on the stress they need to withstand. Proper usage of joints requires understanding their structure, application fields, and parameters. Advantages of threaded joints include their reliability under high loads, ease of assembly and disassembly, cost-effectiveness, and standardized dimensions. Threads are cut on cylindrical or conical surfaces, though cylindrical threads are most common. For tight joints, conical threads are used. Threads are called right-hand if they run from left to right, and left-hand if from right to left. The most common type in mechanical engineering is the metric thread, which has a triangular profile and an angle of 60°. Metric threads can be coarse or fine, depending on their pitch. With keyand splinejoints, components likepulleys, gears, andcouplings are mounted onshafts. These joints primarily bear torque. A key joint typically consists of a shaft, a key, and a hub (e.g., pulley, gear, sprocket). The key transmits the torque. The main **advantages** of key joints are their simple structure, ease of assembly/disassembly, and cost-effectiveness. **Disadvantages** include the need to machine keyways, which reduces shaft strength. Therefore, key joints are not recommended for dynamically loaded or high-speed shafts. Also, each key mustbe custom-fitted, making them unsuitablefor mass production. Key joints can be interference or clearance fits. Prismatic and segmental keys are used for clearance fits, while cylindrical and wedge-shaped keys are used for interference fits. Standard keys are made from carbon or alloy steel with a minimum strength of 500 MPa. Permissible stress values depend ontheoperating conditionsand material strength of theshaft and sleeve. A spline joint is formed when grooves are cut on both the shaft and hub, aligning with each other. Advantages over key joints include: better centering of parts, ability to move components page2237 INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE ISSN:2692-5206,ImpactFactor:12,23 AmericanAcademicpublishers,volume05,issue05,2025 Journal: https://www.academicpublishers.org/journals/index.php/ijai along the shaft, higher torque transmission capacity for the same size, and reliable performance under impact loads. All spline dimensions are standardized, and shapes include rectangular and triangular profiles, with rectangular being the most common. Triangular splines are used in fixed jointsfor transmittingsmallertorques. Among non-separable joints,welded and riveted joints are widely used today. Welded jointsare used to join parts in butt, lap, and corner configurations. Welding is the process of permanently joining components by heating and deforming them to create atomic bonds. There are over 60 types of welding, including arc, electroslag, electron beam, plasma, laser, and gas welding. Welding can be manual, semi-automatic, or automatic. In mechanical engineering, electric arc andgas welding are most common. Welding is used for cracks, notches, fractures, and broken parts, as well as for joining components. Arc welding uses AC or DC power sources (welding transformers or rectifiers). In DCwelding, parts can beconnected to thenegative (reverse polarity) or positive(direct polarity) terminal. Moreheat is generated when thepart isconnected tothepositiveterminal. Before welding, edges are beveled, cleaned, and degreased using solvents or caustic soda. After cooling, welds are finished flush with thesurface orsmoothed fora uniform appearance. Steel parts are welded with wire electrodes (Sv-08, Sv-08GA, etc.) of 1–12 mm diameter. The wire is coated with a flux that stabilizes the arc, protects the weld from atmospheric effects, and improves weld quality. Easily weldable low-carbon and low-alloy steels (e.g., 15X, 20X) are welded with E-34