Knowledge of machining worm:
Module: Mx
Pitch: P=3.14*Mx
Tooth height: 2.2*Mx
Major diameter: d
Pitch diameter: d-2*Mx
Trail: d-4.4*Mx
Tooth thickness: 1.57*Mx
Tooth crest width: 0.842*Mx
Slot bottom width: 0.7*Mx
Three needle measuring method:
The method of measuring the pitch diameter of a thread with a measuring needle is called the three-needle measuring method. When measuring, place three measuring needles with the same diameter D in the thread groove, and then use an appropriate measuring tool (such as a micrometer, etc.) to measure the size of the size M. Verify that the pitch diameter of the thread being machined is correct.
The calculation formula of the pitch diameter of the thread: d2=M－D
t*ctg
M: the value measured by the micrometer (mm),
D: Measuring needle diameter (mm),
α/2: half angle of tooth shape,
t: Workpiece pitch or worm circumference (mm)
The calculation formula of the measuring needle diameter D: D=If the thread profile angle is known, the following simplified formula can also be used to calculate: the thread profile angle α Simplified formula
29° D=0.516t
30° D=0.518t
40° D=0.533t
55° D=0.564t
60° D=0.577t
Measure the thread of M24*1.5 with three needles. Knowing that M=24.325, what is the diameter D of the measuring needle and the pitch diameter d2 of the thread? Solution ∵ α = 60° substituting D=0.577t into D=0.577*1.5=0.8655mm ∴ d2=24.325－0.8655(1 1/0.5) 1.5*1.732/0.5=23.0275mm is different from the theoretical value (d2=23.026) △=23.0275-23.026=0.015mm, it can be seen that the difference is very small. In fact, the pitch diameter of the thread can generally be checked from the thread standard or directly indicated on the part drawing. Therefore, as long as the above formula for calculating the thread pitch diameter is shifted and changed, the calculation of the micrometer can be obtained. The obtained reading formula: M=d2 D-t*ctg If the tooth profile angle is known, the following simplified formula can also be used to calculate: Thread profile angle α Simplified formula
29° M=d2 4.994D－1.933t
30° M=d2 4.864D－1.886t
40° M=d2 3.924D－1.374t
55° M=d2 3.166D－0.960t
60° M=d2 3D－0.866t
Use the three-needle method to measure the thread of M24*1.5. It is known that D = 0.866mm and d2 = 23.026mm. What should be the reading value of the micrometer? Solution ∵ α = 60° Substitute the above formula M = d2 3D－0.866t = 23.026＋3＊0.866－0.866＊1.5＝24.325mm three needle measurement: 60 degrees M
=d2 plus 3dD-0.866P; 55 degrees M=d2 plus 3.166dD-0.96p;
Calculation of steel needle dD:
P÷(2*cos,a/2) 60 degree steel needle calculation 0.577P; 55 degree 0.564P; a tooth profile angle, p thread pitch, dD steel needle straight longitude, d2 thread middle longitude.
d2=D Dajing-2*3H/8; H=0.866025P (60 degrees) H=0.960491P (55 degrees). In the trapezoidal thread, d2=D-0.5P.
The original triangle height of the 60-degree triangular thread=0.866 pitch P and the profile angle is 60 degrees
Tooth top width=1/8*P Groove bottom width=1/4*P:
Pitch diameter = major diameter (nominal diameter)-0.6495P:
Internal tooth aperture = major diameter (nominal diameter) -1.0825P:
The cutting depth of trapezoidal thread = 0.5 pitch P
Gap Z. (when P=2-4, Z=0.25mm, when P=5-12, Z=0.5mm, when P=16-48, Z=1mm)
The tooth profile angle is 30 degrees, the width of the tooth top=0.366*P, the width of the groove bottom=0.366pP-0.536Z worm:
Pitch = Modulus * 3.14 Depth of one side of the knife = 2.2 * Modulus.
Such as modulus 2 and foreign economics 26.4
The three-needle measurement of steel straight length is 3.4, the middle warp size measured is 27.112 minus 0.1-minus 0.2 is the standard
