What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
1. Correctly select the product a. Before use, confirm whether the mechanical properties of the product can meet the needs of use, such as the tensile strength of the screw and the guaranteed load of the nut. The length of the screw should be selected appropriately, and the 1-2 pitch of the nut will be exposed after tightening. b. Before use, check whether the threads are rough, and whether there is iron filings or dirt between the threads, which often lead to locking. c. The fasteners can be lubricated before use. It is recommended to use butter, molybdenum disulfide, mica, graphite or talc for lubrication. Generally, dipping wax is used for lubrication and anti-locking. [1] 2. Pay attention to the use method when using it. a. The speed and force of screwing in should be appropriate, not too fast or too large. Use a torque wrench or socket wrench as much as possible, and avoid using an adjustable wrench or an electric wrench. Excessive speed will cause the temperature to rise rapidly and cause lock-up. b. In the direction of force, the nut must be screwed in perpendicular to the axis of the screw. c. The use of washers can effectively prevent the problem of over-tightening.
Most electrical appliance manufacturers only require the size and riveting gap to be tested for riveted contact components. There is no clear requirement for riveting strength. Only a few manufacturers perform torsion testing on riveting strength. The torque detection method is as follows: use a saw blade to open a one-shaped groove on the rivet head of the riveted contact element, and then insert a torque wrench into the one-shaped open groove to rotate, and measure the torque value. Because most of the electrical contacts are made of copper-silver alloy, the strength is low, and it is easy to slip during the test, and when a saw blade is used to open the one-shaped groove, the width and depth cannot be accurately positioned, so the measured value fluctuates greatly. , has always been an unsolvable technical problem in the industry.
High-strength fastener materials mainly include ML35, 35K, ML40Cr, ML35CrMo steel, etc., of which 75ML35CrMo steel is imported. The main problems of the material are box segregation, decarburization, cracks and so on. The material needs to be spheroidized and annealed before cold forming, and the annealing is carried out in an oil furnace. There is no protective atmosphere in the furnace, and there is a decarburization phenomenon. 1.2 The high-strength fasteners, mainly grade 12.9, are quenched and tempered on the chain casting furnace production line. The temperature and atmosphere in the furnace are controlled by computer, and Rx gas is used as a protective atmosphere. Heating and anti-oxidation and decarburization can be effectively controlled, and the quality of the fasteners is intact during the heating process. The high-strength fasteners mainly of grade 8.8 are quenched and tempered on the vibrating hearth furnace. Affected by the structure of the vibrating hearth furnace, the sealing performance of the furnace is poor, the Rx atmosphere is not easy to control, the temperature difference of the furnace is large, and the parts are heated in the furnace. The collision and the length of time are inconsistent, and the quality of the fasteners during the heating process is poor, and there are phenomena such as decarburization, bumps, and uneven heating.
self-locking screw comprises a screw main body, a metal screw head is arranged on the upper part of the screw main body, a thread is arranged in the middle part of the screw main body, an interference groove is arranged on both sides of the upper part of the screw main body, and the line of the interference groove is arranged. The included angle is 280-364° with the horizontal line. The bottom of the screw body is provided with an elastic chuck, and the elastic chuck includes an optical axis and a conical head. Guangdong Yueluo Hardware Industry Co., Ltd. Guangdong Yueluo Hardware Industry Co., Ltd. adopts the design of elastic collet, and the screw is provided with threaded segments and interference grooves, so that during the screwing process, the interference groove of the optical axis between the two threaded segments is formed along the screw. The axial elastic force achieves the effect of reliable self-locking, which is easy to use and has high tuning efficiency.
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