# What GB definition accords with in whorl gauge calibrating is medium diameter measurement technique

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1 3 stitch are measured to can make " 3 stitch " what measure a whorl gauge to accord with GB to define directly is medium diameter, must seek solution according to actual pitch Ps " appropriate 3 needles " diametical D0, namely D0=Ps/2cos(α / 2) but, general schoolbook is a basis main pitch seeks solution " appropriate 3 needles " , press a demand it is only " appropriate 3 needles " an approximation; Next, pitch appears arbitrarily, beg by actual pitch " appropriate 3 needles " , its amount will be giant, come true very hard actually; If have a standard (standardization) will decrease " appropriate 3 needles " amount, before can appearing again one kind of problem. As above, the 3 needles that produce by home are chosen, still not be " appropriate diameter " . For this, the author gives out as follows need not " appropriate 3 needles " the method that measures the way in seeking solution. Measure a principle to be able to get M=d2+d0[1+1/sin(α by 3 needles / 2)]-(P/2)cot(α / 2)(1) is become " appropriate 3 needles " diametical D0, main pitch P, α of tooth half horn / when 2 have deviation, by type (1) can get α of M=d2+(d0+ Δ D0)[1+1/sin(/ 2+ Δ α / α of 2)]-[(P+ Δ P)/2]cot(/ α of 2 + Δ / D0=ds of Δ of 2) your D0+ , (P+ Δ P)/2=Ps/2, (α + Δ α ) / 2= α S/2, take the place of to go up type gets S/2)(2) of α of M=d2+ds[1+1/sin(α S/2)]-(Ps/2)cot(finally, the diameter in whorl gauge presses type is calculated before calibrating of S/2)(3) of α of D2=M-ds[1+l/sin(α S/2)]+(Ps/2)cot(, measure a D0, P, α first / S/2 of the real value Ds of 2, Ps, α . And public errand of the diameter in the basis asks to calculate the D2max of two limiting value of D2 of the diameter in going out, D2min, criterion D2max of ≤ of D2min ≤ D2 is become of whorl gauge actual in diameter D2 is contented on when type asks, of whorl gauge in means is acceptable. 2.

2 video laws are measured show in 10 thousand labour on use coordinate law to measure, not only can measure piece those who accord with a definition is medium diameter, still can measure a pitch, tooth half part at the same time, and handy, accurate, measure result and 3 stitch measured value it is better to can compare a gender. If be shown in personal computer 10 thousand labour,go up measure, still can show directly measure data and print piece measure an outcome. Graph the fundamental that 2 microscope measure a way is, side of tooth of affirmatory in giving rectangular coordinates to fasten Xoy whorl is linear the defines linear node coordinate of as columnar as the diameter in the hypothesis generatrix (2) seeing a picture. What the position of generatrix of cylinder of the diameter in the hypothesis should accord with GB/ 14791-1993 is medium diameter definition, namely in diameter cylinder generatrix passes the place with tooth groove and raised equal width, diameter cylinder generatrix defines linear position in, can decide score to nod a method to beg through line segment piece. Of whorl gauge in diameter D2 can adopt a plan the geometrical relation of 2 is begged piece. D2=y14-y24=y11-y21+(1/2)cot(α / in 2){Ps-[(x12-x11)+(x22-x21)]} (4)(4) type: Ps -- actual pitch α / 2 -- operation method of instrument of whorl tooth half horn: In common 10 thousand labour are shown on measure an instrument to measure a system to press video standard (or interference law) adjust, installation of compasses be metricaled is in instrument between two tips (or V form on) , adjust the tooth that gets clarity through convention model video. If the graph is shown 2 times, in whorl axes two side are same on helix groove, pass course of mobile instrument vertical guide, the node of dotted line of rice word center that makes ocular medium and side position of tooth of aleatoric photograph adjacent 11, 12, 13 and 21, 22, 23 mutual jackknife undertake reading, namely 11(X11, y11) , 12(x12, y11) , 13(x13, y11) and 21(X21, y21) , 22(x22, y21) , 23(x23, y21) . When measuring, the instrument fore-and-aft reading is adjusted be X=(x11+x12+Ps/2)/2 and locking. Mobile and transverse bracket (forbidden and fore-and-aft mobile) , make dotted line of rice word center and tooth side parallel overlap transversely each other reading Y14, get Y24 with manage, be measured of whorl in diameter D2=y14-y24. In personal computer 10 thousand labour are shown on measure the combination that can carry software function item to use, indirect favourable geographical position seeks the way in solution with program of personal computer software or seek solution from program according to article method. BASIC source program gives out below: 10 INPUT " data-in " X11, x12, x13, y11, k1, x21, x22, x23, y21, k2, p 20 X14 =[(X11 + X12)/2 +(X12 + X13)/ 2]/ 2 30 B1 = Y11 - K1*X12: Y14 = K1*X14 + B1 40 X24 =[(X21 + X22)/ 2 +(X22 + X23)/ 2]/ 2 50 B2 = Y21 - K2*X22, y24 = K2*X24 + B2 60 D2 = ABS(Y14 - Y24) 70 PRINT " screw center diameter is " , d2 80 X15 =(X11 + X12 + P/ 2)/ 2: Y15 = K1*X15 + B1 90 X25 =(X21 + X22 + P/ 2)/ 2: Y25 = K2*K25 + B2 100 D(2)= ABS(Y15 - Y25) 110 PRINT " whorl is onefold in diameter is: " , d(2) 120 END2.

3 umbriferous laws are measured thimble is installed on measuring projector, after adjusting two thimble to agree even line and workbench shift direction, be outfit of gauge of the whorl that be measured between two thimble and locking. Choose multiple of proper and umbriferous enlarge, adjust aperture, focal length to wait, make the tooth of whorl a side enlarge shows video and clearly go up in screen. The whorl tooth that gets on screen flimsy video, with transparent triangle feet, pencil well and truly draw teething linear part (pencil line is finer better, it is accurate) with can looking clear. (A) makes base line of tooth enlarge graph (tooth of B) other a side measure enlarge of side of graph 3(a) tooth tooth to pursue quite with enlarge graph (B) pursues in enlarge definition of the diameter in going up pursues point-blank 4 magnify too tooth medium near track line, make the base line of one parallel and whorl axes, base line and tooth side are handed in at 11, 12, 13 at 3 o'clock, this is the standard enlarge plan that the diameter in whorl gauge surveys. Write down at this moment transverse (radial) instrument reading Y11(sees graph 3a) . Make another side tooth enlarge video show go up in screen, pass the adjustment with vertical, transverse instrument, make video chamfer of as same as enlarge graph helix is nodded accordingly (A) , (B) , (C) and A, b, c coincide, when cannot at the same time when coincide, should assure (B) and B coincide, (A) and A and (C) and C were in at 2 o'clock have same symmetry space, write down Y(A)(of next transverse instrument reading to see graph 3b) at this moment. Get off side of the tooth that give tooth is represented on screen linear enlarge pursues (4a) seeing a picture, put its on drawing board to undertake geometry constructive, decide A, b and B, the midpoint E of C and F, the perpendicular bisector that makes EF again (in diameter definition is sharp) hand in at nodding D point-blank with tooth side, measure a D to nod the distance H(to base line to see graph 4b) next. Of gauge of the whorl that be measured in diameter (2) seeing a picture presses type begs piece: D2= | Y(A)-yA | In ± 2H/M type: M -- enlarge multiple (in the center diameter definition is sharp with in positive sign is taken when the nodical D of track line is located in between B, C; Negative sign is taken when be located in between A, B) the measurement technique of 3 kinds of screw center diameter that the article offers 3 epilogue is accorded with in diameter definition, nonexistent principle error, not only measure handy, accuracy is tall, and can have compared of 3 kinds of methods than the gender. "3 stitch " when the diameter in measuring, need not beg any correction; Need not have complex mathematical operation to amend each parameter. "Video law " when the diameter in measuring, measurement point is taken in in on track line, pitch with error of tooth half horn the diameter in be opposite is measured do not produce an effect; The deflection volume that measures plane and height of central microscope centre of percussion does not appear in measuring a process as a result of this kind of method, as a result of,can decrease whorl axes and measure axes not coincide and the first-order error that cause. "Video law " metrical accuracy, besides the error that measures an instrument, still depend on tooth of the treatment precision of gauge itself, enlarge image and tooth side depicts the skill with quality and constructive geometry and accuracy. Error analysis makes clear, 3 kinds of methods all can satisfy the article the accurate demand that the diameter in common thread gauge gauges. CNC Milling CNC Machining