What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
As the preferred embodiment of the above-mentioned embodiment, the motor 41 is provided with a thruster 46 that moves the cutting wheel 42 toward the conveying device 3. When the screw needs to be slotted, the thruster 46 generates a thrust toward the screw, and the motor 41 generates a thrust in the direction of the screw. Under the action, the groove is moved along the track 47 toward the screw. The other end of the motor 41 is provided with a bearing 45, and the output end of the motor is provided with a special-shaped wheel 44. The special-shaped wheel 44 is geared to the bearing 45. The wheel 42 is close to or away from the conveying device 3. When the grooving is completed, the special-shaped wheel 44 rotates and drives the bearing 45 to generate the opposite force from the above-mentioned thrust, so that the motor 41 moves back to the initial position along the track 48.
Most of the blind hole installation rivets have the characteristics of light weight, reliable connection, high strength, and convenient and quick installation. For example, blind rivets have been widely used in various aerospace vehicles.
flat washer is also called a flat washer. It is mainly stamped out of an iron plate. The shape is generally a flat washer with a hole in the middle. The size of this hole is generally determined according to customer requirements. There are 9 standards for flat washers in my country. From 2000 to 2002, GB/T97.3-2000, GB/T5286-2001, GB/T95-2002, GB/T96.1-2002, GB/T96.2 were approved and released respectively. -2002, GB/T97.1-2002, GB/T97.2-2002, GB/T97.4-2002 and GB/T5287-2002 Standard for flat washers. According to the performance grade of the flat washer, the author recommends the use of materials: ST12, ST13, Q235, Q215, Q195, etc. can be selected for the 100HV grade, and the surface hardness can reach about 110HV; 08F, 08Al, 10, 10F, etc. can be selected for the 140HV grade etc., the surface hardness can reach about 140HV; for 200HV and 300HV grades, 45, 50, 60, 70 or 65Mn steel should be selected, which can be quenched and tempered by heat treatment to meet the technical requirements of 200~300HV and 300~400HV. Because according to the standard, flat washers of 100HV and 140HV grades can be manufactured from mild steel. Most enterprises use Baosteel materials when selecting materials, which is convenient for cold stamping. The following is a brief description of Baosteel's standards. Compared with the BZJ407-1999 standard, there are major changes in Continuous Cold Rolled Low-Carbon Steel Plates and Strips and the enterprise standard: (1) The grades have been revised and integrated, and the grades have been changed from 8 commonly used to 5. St12 is changed to DC01; ST13 is changed to DC03; St14, St15 is changed to DC04; BSC2 is changed to DC05; St16, St14-T, BSC3 is changed to DC06. (2) The surface quality level is changed from two to three: the higher-level finishing surface (FB), the surface is allowed to have a small amount of defects that do not affect the formability and coating and plating adhesion, such as slight scratches, indentations, Pock, roll printing and oxidation color, etc. Premium Finished Surface (FC) products have no visible defects on the better of the two sides and must meet at least FB requirements on the other side. The super-advanced finishing (FD) product must not have any defects on the better side of the two sides, that is, it cannot affect the appearance quality after painting or the appearance quality after electroplating, and the other side must at least meet the requirements of FB. (3) The surface structure is modified from four to two, and the control value of surface roughness is increased. The average roughness Ra when the surface structure is pitted (D) is 0.6 μm. (4) The provisions on Si and residual elements in the chemical composition of the five grades have been cancelled, and the contents of elements such as C, S, and Alt have been revised.
screw is a common connecting piece, a tool that uses the physical and mathematical principles of the circular rotation and friction of an object to fasten the parts of the object step by step. 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 a great invention of human beings. A traditional screw is generally set as a screw head at one end and a screw rod at the other end, which cooperates with an external nut to fasten the connector between the screw head and the nut. However, such as some home appliance modules, chassis and other electrical appliances, the modules and boxes fixed by traditional screws often fasten many parts together by screws. During maintenance, it is necessary to disassemble all parts of the maintenance part, which is very troublesome. Therefore, a new type of screw structure that can be connected at both ends and can realize layered installation is required. During maintenance, only the connecting layer of the maintenance part needs to be disassembled, and neither the exterior nor the interior needs to be disassembled.
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