How to design and produce radial interference fit threads? Please ask your friends for help.

However, it is difficult for us to find relevant standards or information. This paper introduces a technology for producing radial interference (interference) mating threads by equivalent selection of relevant mating tolerance zones with GB 1800 tolerance and mating standards. For the interference fit between this group of holes and the shaft, we only need to select the relevant tolerance zone according to GB 1800 Tolerance and Fit standard. However, it is difficult for us to find relevant standards or information about how to design threads with interference (interference) fit. This paper introduces a technology for producing radial interference (interference) mating threads by equivalent selection of relevant mating tolerance zones with GB 1800 tolerance and mating standards. This technical scheme is suitable for metric, English, radial pitch, modulus and other threads. This set of technology is quoted from a set of related contents in the patent technology of high-precision thread invention. The biggest advantage of this technology is that you can choose the tolerance zone of our radial interference fit thread pair according to our previous understanding of the tolerance zone of hole-shaft fit and interference fit. This kind of thread pair can be easily disassembled and reused without damaging the thread profile. The difficulty in designing and manufacturing interference fit threads lies in how to freely screw in and screw out this pair of threads without destroying the thread profile. 1. two standards for reference. The first is the mating datum: the mating datum of this radial interference fit thread pair is the major diameter of the thread, just like the mating of the hole shaft. You can understand this vividly. Bottom hole system is generally selected. Second, the radial interference (interference): Considering the feature that the thread can be disassembled repeatedly, the interference (interference) of this radial interference fit thread pair should be larger than that of the common hole shaft fit, so the tolerance zone should be 1-2. The factors that need to be considered are as follows: (1) when the screw pair is matched, the radial contact area of the large diameter of the screw thread is much smaller than that of the hole shaft; When repeatedly disassembled, the thread with large diameter will produce certain plastic deformation; There are also obvious differences between materials with different plasticity; Different use occasions (such as strong vibration and high temperature). This needs to be analyzed in practical application. If the radial dimension needs grinding or electroplating, the corresponding process parameters should be adjusted. 2. In the production and inspection of the radial interference fit thread pair produced according to the basic hole system, the tooth profile of the external thread is formed by a special high-precision thread cutter, and only the outer diameter tolerance can be inspected. The outer diameter (large diameter) can be machined with a cylindrical grinder, and the accuracy can reach more than IT4. The inspection method is the same as the inspection of the outer diameter of the outer circle; The tooth profile of internal thread can be processed by ordinary internal thread cutter, and only its large diameter can be tested. Large-diameter single-parameter gauges (including general gauges and stop gauges) can be used for testing. The gauge can be produced by itself and manufactured according to the rules of traditional hole gauges. The production process, equipment and cost of this radial interference thread are the same as those of traditional threads and ordinary parts. 3. A design skill: Because this kind of radial interference fit thread pair is a large diameter fit thread pair, in order to make the first few threads can be screwed in by hand, we only need to choose the negative deviation (we call it the lead-in section) when designing the outer diameters of the first few threads, and use the inclined plane to transition to the positive deviation fit section. This makes it easy to screw in the internal and external threads of the thread pair. 4. The radial interference fit thread pair can be assembled, disassembled and used repeatedly. Its interference part is only a large diameter, not the interference of the whole tooth profile, so repeated assembly and disassembly will not damage the main mating surface of the thread profile. 5. Performance The biggest feature of this radial interference fit thread pair is that it eliminates the radial clearance between the internal and external threads, and realizes the high bearing capacity of the full-tooth type, which is 20% higher than the guaranteed load theory of traditional threads; It has much better anti-loosening performance and certain self-locking performance (not completely self-locking) than traditional threads; It can replace the screw pair that cannot be disassembled repeatedly, reduce the cost by more than half, and the performance is much more reliable. At the same time, the radial interference fit thread pair with large diameter and small diameter can have sealing performance. This is the case with non-tapered mating sealing threads. 6. Design, production and matching of high-precision threads The selection, production and inspection methods of high-precision threads are the same as above, but the difference is that we choose the tolerance zone of fit clearance without adding the structure of the lead-in section.