(1) Discuss the diameter of spring wire d: the diameter of the steel wire used to manufacture the spring.
(2) Spring outer diameter D: The maximum outer diameter of the spring.
(3) Spring inner diameter D1: The minimum outer diameter of the spring.
(4) Spring diameter D2: The average diameter of the spring. Their calculation formula is: D2=(D+D1) ÷ 2=D1+d=D-d
(5) T: Except for the support ring, the axial distance between the corresponding points of the adjacent two coils of the spring on the pitch diameter becomes the pitch, denoted by t.
(6) Effective number of turns n: The number of turns that a spring can maintain at the same pitch.
(7) Number of support coils n2: In order to ensure uniform force on the spring during operation and ensure that the axis is perpendicular to the end face, the two ends of the spring are often tightened together during manufacturing. The number of tight turns only serves as a support and is called a support ring. There are generally 1.5T, 2T, 2.5T, and the commonly used ones are 2T.
(8) Total number of turns n1: The sum of effective turns and support rings. Namely, n1=n+n2
(9) Free height H0: The height of the spring without external force. Calculate from the following equation: H0=nt+(n2-0.5) d=nt+1.5d (when n2=2)
(10) Spring unfolding length L: The length of steel wire required for winding the spring. L ≈ n1（ Л D2) 2+n2 (pressure spring) L= Л D2 n+hook extension length (tension spring) (11) Spiral direction: There are left and right rotations, commonly right rotations, and those not specified in the drawing generally use right rotations.
Standard drawing method for springs:
(1) On the view of parallel spiral spring lines, the contour lines of each coil are drawn as straight lines.
(2) Springs with an effective number of more than 4 coils can only be drawn with 1-2 coils at both ends (excluding support coils). The middle is connected by dotted lines passing through the center of the spring steel wire.
(3) In the drawing, when the direction of rotation of the spring is not specified, all spiral springs are drawn as right-handed, and left-handed springs are also drawn as right-handed, but the word “left” should be indicated.