Обший каталог Yamawa 2016 - 2017 - страница 793

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10. About UNJ Threads UNJ Threads are Unified Threads used for Aircrafts. In order to protect the breakage from thread bottom of external threads, UNJ thread defines the minor diameter larger than Unified thread and the Description of products range of root bottom R. And accuracy of threads is only defined in highest classes of unified threads, 3A of external threads and 3B of internal threads. UNJ Threads were initially defined as a MIL Standard (American Millitary Standard ). It is now superseded by American SAE Standard ( Automobile Engineers Association). Standard Numbers are as follows: SAE AS8879D Screw Threads - UNJ Profile, Inch Controlled Radius Root with Increased Minor Diameter Basic profile of UNJ thread is shown in the drawing below. Truncation on thread root of external threads is 5H/16, that is, H/16 larger than H/4 of normal Unified Thread's truncation. And radius of thread root is 0.18042P~0.15011P. ■ Basic Profile of UNJ Thread H8ー Internal Threads H2ー H1 H 30° 30° H2ー 60° External Threads d1 or D1 d2 or D2 156ーH d or D P H =0.866025P D =d 【reference】 H1 =9H/16 D2 =d2 9H/16 =0.487139P d2 =d-0.649519P D1 =d1 H/2 (8H/16)=0.433013P d1 =d-0.974278P P =25.4/n 5H/16 =0.270633P n =Threads per inch H/8 (2H/16)=0.108253P Bored hole size is recommended to be a little larger than that for normal unified threads considering that the minor diameter of UNJ series is larger than that of normal Unified Threads. unit: mm Minor Diameter Size Bored Hole Size Maximum Minimum No.6 - 32 UNJC 2.938 2.734 2.89 No.6 - 40 UNJF 3.053 2.888 3.01 No.8 - 32 UNJC 3.599 3.394 3.55 No.8 - 36 UNJF 3.662 3.480 3.62 No.10 - 24 UNJC 4.064 3.795 4.00 No.10 - 32 UNJF 4.254 4.054 4.20 No.12 - 24 UNJC 4.704 4.456 4.64 No.12 - 28 UNJF 4.815 4.603 4.76 1/4 - 20 UNJC 5.387 5.114 5.32 1/4 - 28 UNJF 5.661 5.467 5.61 5/16 - 18 UNJC 6.832 6.564 6.76 5/16 - 24 UNJF 7.109 6.907 7.06 3/8 - 16 UNJC 8.255 7.979 8.19 Information Technical 3/8 - 24 UNJF 8.679 8.494 8.63 7/16 - 14 UNJC 9.639 9.348 9.57 7/16 - 20 UNJF 10.083 9.876 10.03 1/2 - 13 UNJC 11.094 10.798 11.02 1/2 - 20 UNJF 11.661 11.464 11.61 Technical-18 789