What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The shear strength of a metal material refers to the ability of the material to withstand shearing force, which refers to the strength of the external force perpendicular to the material axis and shearing the material. The test is usually to install the cylindrical pin into the specified fixture, and the gap between the supporting part and the loading part is required to be no more than 0.15mm, and then force is applied to test the shear strength of the material.
In the fastening connection parts and parts assembly of various equipment and tooling, if the screw and nut anti-loosening treatment is required, there is a contradiction between anti-loosening and tightening or tightening and loosening. For example, the resistance is large when tightening. , or the resistance is large when loosening, or the anti-loosening effect is not good, or the service life is short, and it will be scrapped after 2 to 3 times of use. In a word, all kinds of anti-loosening nuts have the above problems at present. Therefore, it is necessary to utilise a new type of anti-loosening nut with low resistance when tightening or loosening, but with better anti-loosening effect and long service life.
Knurled copper nuts are mainly used for injection molding, hardware springs, special-shaped springs, craft gift springs, battery spring sheets, spring antennas, key rings, phosphor bronze spring CNC automatic lathe turning parts (copper car parts, iron car parts, aluminum car parts) , metal stamping parts, electronic hardware, iron shaft, single flower shaft, multi flower shaft, iron pin, non-standard screw and nut, connecting parts, fasteners, wire forming (metal wire business card holder, model aircraft landing gear, S hook , R-type latch, triangle buckle, D-type buckle) and other hardware products belong to the copper nut series.
When the mechanical components are installed on the concrete foundation, the J-shaped and L-shaped ends of the bolts are embedded in the concrete for use. The tensile capacity of the anchor bolt is the tensile capacity of the round steel itself. The size is equal to the cross-sectional area multiplied by the allowable stress value (Q235B: 140MPa, 16Mn or Q345: 170MPA), which is the allowable tensile capacity at the time of design. The anchor bolts are generally made of Q235 steel, which is smooth and round. Rebar (Q345) is strong, and the thread of the nut is not as easy to be round. For light round anchor bolts, the burial depth is generally 25 times its diameter, and then a 90-degree hook with a length of about 120mm is made. If the bolt diameter is large (such as 45mm) and the buried depth is too deep, a square plate can be welded at the end of the bolt, that is, a large head can be made (but there are certain requirements). The burial depth and hook are all to ensure the friction between the bolt and the foundation, so as not to cause the bolt to be pulled out and damaged.
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