Standard Parts and Common Parts

Standard parts and common parts

Standard parts:The structure form, size, surface quality and representation method have been standardized. For example, threaded fasteners, keys, pins, rolling bearings and springs, etc. Standard parts are widely used and are produced by professional factories.Common parts:The structure shape and size of some parts have a unified standard, and the parts that have a specified drawing method in the drawing, such as gears, splines, welding parts, etc.

Drawing of threaded fastener connectionsPrescribed drawing method:(1) Draw a thick solid line on the contact surface of the two parts, and draw two thick solid lines on the non-contact surface.(2) When the cutting plane is cut along the axis (or symmetrical line) of the solid parts or standard parts (bolts, nuts, washers, etc.), these parts are drawn without cutting, that is, their outline is still drawn.(3) In the section view, the section lines of the two parts in contact with each other should be opposite in direction or at different intervalsThe same part in each section view, section line direction and spacing should be the same.

Key markingThe marking of the key consists of three parts: standard number, name, type and size.For example, A type A (round head) ordinary flat key, b=12mm,h=8mm, L=50 mm, which is marked:GB/T 1096 key 12 x 8 x 50It is marked as: for example, type c (single round head) ordinary flat key, b=18mm,h=11mm,L=100 mmGB/T 1096  C 18× 11× 100The “A” word of the type A key in the mark is omitted, and the type B and type C should be marked with “B” and “C”.

Parameters of cylindrical helical compression springs1. Wire diameter d: diameter of wire winding spring.2, the inner diameter D, outer diameter D and middle diameter D of the spring,The diameter of the inner ring of the spring is called the inside diameter, the diameter of the outer ring of the spring is called the outside diameter, and the average value of the inside and outside diameter of the spring is called the middle diameter, D,=(D+D,)12.3. Pitch t of the spring:The axial distance of the center line of the section of two adjacent rings, except for the supporting rings at both ends.