|
The ISO metric screw threads are the world-wide most commonly used type of general-purpose screw thread.〔(ISO/TC/ 1 Business Plan ), 2007-03-05, Version 1.3. Table 3: The market share of each screw thread, p. 7.〕 They were one of the first international standards agreed when the International Organization for Standardization was set up in 1947. The "M" designation for metric screws indicates the nominal outer diameter of the screw, in millimeters (e.g., an M6 screw has a nominal outer diameter of 6 millimeters). ==Basic profile== The design principles of ISO general-purpose metric screw threads ("M" series threads) are defined in international standard ISO 68-1.〔 〕 Each thread is characterized by its major diameter, ''D'' (''D''maj in the diagram), and its pitch, ''P''. ISO metric threads consist of a symmetric V-shaped thread. In the plane of the thread axis, the flanks of the V have an angle of 60° to each other. The thread depth is 0.614 × pitch. The outermost and the innermost of the height ''H'' of the V-shape are cut off from the profile. The relationship between the height, ''H'', and the pitch, ''P'', is described by the following equation:〔.〕 or In an external (male) thread (e.g., on a bolt), the major diameter ''D''maj and the minor diameter ''D''min define ''maximum'' dimensions of the thread. This means that the external thread must end flat at ''D''maj, but can be rounded out below the minor diameter ''D''min. Conversely, in an internal (female) thread (e.g., in a nut), the major and minor diameters are ''minimum'' dimensions, therefore the thread profile must end flat at ''D''min but may be rounded out beyond ''D''maj. The minor diameter ''D''min and effective pitch diameter ''D''p are derived from the major diameter and pitch as : 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「ISO metric screw thread」の詳細全文を読む スポンサード リンク
|