1. The role of flat pad 1. Enlarge the contact area bet […]
1. The role of flat pad
1. Enlarge the contact area between the screw and the machine;
2. Eliminate the damage to the surface of the equipment when the spring pads are unloaded. When used, it must be: a spring pad and a flat pad, the flat pad is next to the surface layer of the device, and the spring pad is between the flat pad and the nut. The flat pad is to increase the force surface of the screw. In order to prevent the screws from loosening, the spring pads play a certain amount of buffer protection when subjected to force. Although flat pads can be used as sacrificial pads.
3. But more often it is used as a supplementary pad or flat pressure pad.
Second, the role of spring cushions
The main purpose of spring washers is to relax. They are generally used in occasions where the bolt pre-tightening force is not high and the dynamic load is small. At present, a large number of tests have confirmed that the spring washer is not effective in preventing loosening. Therefore, it is not recommended to use the spring washer for tightening occasions with relatively high pre-tightening force and where the connection is more important.
1. The function of the spring washer is that after the nut is tightened, the spring washer gives the nut an elastic force to tighten the nut to make it not easy to fall off. The basic function of the spring is to give a force to the nut after tightening the nut to increase the friction between the nut and the bolt;
2. Generally, flat pads are not used when spring pads are used (except for protecting the surface of the fasteners and the mounting surface, consider using flat pads and spring pads);
3. Flat washers are generally used in connecting parts, one is soft and the other is hard and brittle. Its main function is to increase the contact area, disperse the pressure, and prevent the soft texture from being crushed.
3. When to use flat pads and when to use elastic pads
1. Under normal circumstances, only flat pads can be used when the load is relatively small and the load is not subject to vibration.
2. In the case of relatively large loads and vibration loads, a combination of flat pads and spring pads must be used.
3. Spring washers are basically not used alone, they are all used in combination.
Under what circumstances do we need to use washers for bolted connections?
The connection of shear stress bolts (reamed hole bolts) generally does not require washers. First, shear stress bolts do not require too much pre-tightening force, and do not bear axial force during work. In this case, bolt holes are generally relatively small. The bearing surface of the nut or bolt head is generally relatively large, and the connected parts can bear it without reducing the compressive stress.
When flange nuts or bolts are used, because the contact area of flange bolts or nuts is large, washers are usually no longer needed to increase the contact area and reduce the compressive stress.