When do you need a washer for bolting?
We often see some bolted joints in the mechanical equipment, some bolts do not use washers, some bolts use flat washers, some use spring washers, we must design Don't use a washer? So entangled, have you got the same entanglement? If so, today's article is for you. Bolted connection - no washer Bolted joints - with flat washers Stud connection----spring washer anti-loose What is the role of the gasket? Flat Washers; In the case where the bolt needs to be frequently disassembled, in order to protect the surface of the connected member from being scratched, it is generally necessary to place a flat washer at the position of the nut or the bolt head, so that the surface of the connected member is prevented from being scratched. In some joints where the friction coefficient is relatively precise, such as high-strength pre-stressed bolts, it is necessary to place flat washers on the nut end, because bolts, nuts and washers are provided by the same manufacturer in this case, and the bolt manufacturer needs to The nut and washer are treated accordingly to ensure a consistent coefficient of friction between the nut and the washer. When the bolt strength is relatively high and the allowable compressive stress of the connected member is relatively low, in order to reduce the compressive stress of the pressure receiving surface of the joined member, it is generally required to add a flat washer. In the bolt connection, the pressure transmission of the bearing surface of the bolt head or the nut is gradually enlarged in a flared shape, and the larger the bearing surface is, the smaller the compressive stress is, so that the flat washer can reduce the compressive stress of the contact surface of the connected piece. Ensure that the bolt connection is effective. Pre-pressure transmission section of bolt in bolted connection In some cases, in order to ensure the one-to-one correspondence between the bolt holes between the two connecting members, we need to increase the diameter of the hole to compensate for the positional deviation of the hole. When the bolt hole exceeds the standard requirements, it is necessary to add a flat washer. Sometimes for the convenience of installation and adjustment, the bolt holes will be made into long holes, so that the mounting position of the workpiece can be adjusted within a certain range. When using long holes, thick flat washers should be used, more specific cases, even special washers or multiple washer. Spring washer The main purpose of the spring washer is to relax, generally used in places where the pre-tightening force of the bolt is not high and the dynamic load is small. When the clamping length of the bolt is relatively short, the stress relaxation of the bolt is obvious, and the spring washer can compensate for the stress relaxation. Experiments have shown that under dynamic load conditions, high-strength bolt-connected spring washers have almost no anti-loosening effect and can cause rapid damping of bolt clamping force. Therefore, spring washers have rarely been used in high-strength bolts. When the bolt connection requires a washer, we have already made it clear, then what can be done without a washer? 1. The shear stress bolt connection generally does not require a washer. Firstly, the bolt does not need too much pre-tightening force and does not bear axial force during work. In this case, the bolt hole is generally small, and the nut or bolt head bearing surface is small. Generally, it is relatively large, and it does not need to reduce the compressive stress, and can be withstood by the connecting member. 2. When a flange nut or bolt is used, the washer is not required, and the bearing surface of the flange nut is large enough. Polycarbonate Corrugated Sheet High Light Pc Sheet,Polycarbonate Sheet Double Wall,Polycarbonate Corrugated Sheet,Polycarbonate Wave Panel SuZhou NiLin New Material Technology Co.,Ltd , https://www.sznlpc-sheets.com
