What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
1. The expansion phenomenon of the spring washer is generally not the problem of the spring washer itself. 2. The spring washer with the expansion ring must be subjected to a radial external tension. The external tension is derived from the tightening axial force generated by the tightening torque. The chamfer creates a radial component of the axial clamping force, which expands the opening of the spring washer. The smaller the chamfer diameter, the greater the possibility of ring expansion. 4. Adding a flat washer between the nut and the spring washer helps to slow down or prevent the expansion of the ring, but the flat washer is too thin or too soft. Prevent ring expansion 5. The reason for the hydrogen embrittlement fracture of spring washers is generally due to unreasonable heat treatment process and the failure of hydrogen removal treatment after electro-galvanizing. A large number of tests and long-term practical experience have confirmed the above analysis.
At present, with the development of my country's railway industry, many railway fastener systems involve T-bolts. The structure is shown in Figure 1. The dimensions that need to be inspected are head width A, head length B, and head straight table height. C. The height of the head slope D, the total length of the bolt E, and the major diameter of the bolt F. Due to the irregular shape of these places to be inspected, the measurement is difficult. The measurement of general measuring tools is not only slow, but also difficult to control human errors, resulting in some extreme upper limits and There are disputes and misjudgments about the size of the extreme lower limit when judging qualified and unqualified.
Stainless steel screw wire is also called stainless steel cold pier wire, which is mainly used for various fasteners, such as mechanical parts, electronic application parts, etc. Corresponding anti-corrosion properties and mechanical properties can be obtained according to different materials. In order to obtain a better formability during cold forging, choose high quality. The appropriate material of the wire is particularly important.
At present, the commonly used locking structure is a split pin (hereinafter referred to as a cotter pin type adjustment nut) or knocking the sheet on the adjustment nut into the steering knuckle groove (hereinafter referred to as a sheet type adjustment nut), these two structures are mainly used in single row Bearings are barely used in bearing units and hub bearing units. The former has a complicated structure and the cotter pin is easy to fall off; the latter requires workers to control the press-in force. Too much pressure can easily lead to the cracking of the sheet structure on the adjusting nut, and too little pressure can easily make the adjusting nut failure, and is impacted in the axial direction.
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