National Standard of the People's Republic of China Trapezoidal thread profile Metric trapezoidal screw threads-ProfileUDC 621.882.082.4 GB 5796.1-86 Replace* This standard specifies the basic profile and maximum solid profile of trapezoidal threads for general use. This standard is equivalent to the international standard ISO2901-1977 "ISO metric trapezoidal thread-basic profile and maximum solid profile". Basic profile The basic profile is the theoretical profile formed by cutting off the top and bottom of the original triangle. The profile and its parameters are shown in Figure 1. 30° Thread axis Figure 1 Basic tooth profile In the figure: D Major diameter of internal thread, Major diameter of external thread (nominal diameter), Dz——middle diameter of internal thread;bZxz.net d2——middle diameter of external thread; Di—minor diameter of internal thread; -minor diameter of external thread; H——height of original triangle -height of basic tooth profile. *Replaces the tooth profile part of GB784-65. Published by the National Bureau of Standards on January 21, 1986 Implemented from January to January 1, 1987 1.1 The dimensions of the basic tooth profile are listed in Table 1. GB 5796.1—86 Table 1 Basic tooth profile dimensions Maximum solid tooth profile 2.1 The maximum solid tooth profile is based on the basic tooth profile and is determined by the gap between major diameters (minor diameters) and the basic deviation of each diameter. The tooth profile and its parameters are shown in Figures 2 and 3. 260 (grass) In the figure: H = 0.5P; GB5796.1—86 Figure 2 Maximum solid tooth profile with zero basic deviationFigure 3 Maximum solid tooth profile with non-zero basic deviation of external thread mid-diameter h3=Ha=i+a. =0.5P+acs a. Tooth top clearance, Z=0.25P=H//2; GB 5796.1—86 d2= D, =d-2Z= d-0.5P; d,=d-2h3=d-2(o.5P+a), s =0.26795es; es--Basic deviation of external thread pitch diameter; D, =d-2H = d- P, D#=d+2acs Rimax =0.5acs R2max =aco 2.2 The maximum solid tooth profile dimensions are listed in Table 2. Table 2 Maximum solid tooth profile dimensions When rolling method is used for processing. The shape of the external thread bottom can be made into a larger arc. In this case, the minor diameter d of the external thread is allowed to be reduced by 3 *D and d3 are the major diameter of the internal thread and the minor diameter of the external thread on the maximum solid tooth profile. 262 GB5796.1-86 Additional Notes: This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China and is under the jurisdiction of the Standardization Research Institute of the Ministry of Machinery Industry. This standard was drafted by the national standard working group for trapezoidal threads, and the main drafters were Yu Yuan and Wang Wenyi. Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.