Summary: Studied the measurement technique of position alignment error of cylinder body aperture, built the crock opening position that is based on a least square method to spend assess model, developed position of opening of cylinder body of 4 crocks of engine to spend special measuring instrument on this foundation. 1 foreword aborning, spend when the position of the aperture group that distributings on the spare parts when according with relevant principle, can use current capacity appearance to undertake detecting commonly. But because connect dosage,appearance establishs actual effect border hard, because this meets what spend to aperture group position to measure,bring difficulty, when assembling engine cylinder body especially, wait for athletic component to assure piston, connecting rod, crankshaft mutual position is exact, inside the tolerancepublic errand limits that must asking limitation of position alignment error of air cylinder aperture. To assure the positional precision of air cylinder aperture, divide outside using reasonable treatment method, position of air cylinder opening spends it is very important also to detect. Go up in engine production, assembly line to suit fast, accurate the need that measures position alignment error of air cylinder aperture, the special measuring instrument with need corresponding development implement. Document considered to use much sensor to decide the measurement technique of aperture heart position and model, but this method is being measured cost and it is certain to measure dependability to go up to still exist limitation, the random error that measures an outcome is bigger. The article puts forward a kind to be based on the method of assess of position alignment error of cylinder body aperture of the least square method and model, developed use at position of opening of cylinder body of 4 crocks of engine to spend metrical special measuring instrument implement. The model of least square method that position of center of 2 weak opening measures is the position of aperture of each cylinder body on affirmatory engine cylinder body to spend, must determine the central position of every aperture above all. The position alignment error of aperture is measured use measure a way relatively, make a standard component above all namely, after the high accuracy of positional precision classics of standard aperture measures an instrument to detect foregone, be measured its as assess what opening position spends is fiducial. Before measuring, undertake to sensor on preexistence standard component corrective, with the measurement of corrective sensor data serves as sensor at 0 o'clock. The basis surveys plan, the measurement in every aperture that be measured is sectional go up to decorate two sensor relatively by 180 ° . Set two sensor to measure a head to install dot of the A that goes up at checking a club, B respectively, o dot is the center that checks a club, r is the diameter of standard aperture, hi1, Hi2 is the aperture that be measured two sensor I second metrical displacement volume, θ I is I second the with X axis included angle when measuring. It is the real center position that determines the aperture that be measured, need pair of Kong Yuan that be measured Zhou Jin is measured for many times all right, construct according to principle of least square method next a least square is round, regard the real center of the aperture that be measured as the position approximately with the O of the centre of a circle of circle of this least square. In O-xy of planar coordinate department, the coordinate that A, B nods is A (xA respectively, YA)=[(r+hi1)cos θ I, (R+hi1)sin θ I)B(xB, ) of π of YB)=[(r+hi2)cos(θ I+ , (π of R+hi2)sin(θ I+ ) ] the midpoint coordinate of linear AB is [(H1-h2)cos(θ / 2) , (H1-h2)sin(θ I/2)] . Set it is on the aperture that be measured to N dot sampling, sampling interval angle is θ =360/N. It is coordinate origin in order to check great center, it is with X axis measure position of rest, criterion the central coordinate of least square circle is (Δ X, Δ Y) , can build model of least square method to be θ of ε 2i=N-1 Σ I=1{[(hi1-hi2)cos I - θ of Δ X]2+[(hi1-hi2)sin I - Δ X]2}=min (i=0, ... , n-1)22 your: ? Ning =0, ε I=0. Should be measured the central coordinate of the least square circle of aperture (Δ X, Δ Y) is (position of opening of cylinder body of 22(1)3 of θ of Σ I=0hi1-hi2sin I of Y=1N-1 of Δ of N2 of θ of Σ I=0hi1-hi2cos I of X=1N-1 of Δ of Y) of Δ X)(Δ is spent measure principle basis to be measured the structural feet of cylinder body aperture, designed measurable the sensor of aperture of 4 cylinder body tests marvellous component device, its assemble a structure. When measuring, device of whole test marvellous component drives next edges in air cylinder two oriented pillar move downward, insert the Kong Zhong that be measured. Every test club configures a pace to enter electric machinery each, use at controlling its whirligig, make sensor measures a head to rotate and get sampling data by the requirement. The sensor installation means of the each aperture that be measured and when measuring place of weak opening center identical, before measuring, need to use standard component corrective sensor. Sensor group measures the signal that each opening position spends. Set NO of the aperture when demarcate standard component. 1, NO.
2, NO.
3, NO.
The coordinate of position of weak opening center of 4 is respectively (Δ X1b, Δ Y1b) , (Δ X2b, Δ Y2b) , (Δ X3b, Δ Y3b) , (Δ X4b, Δ Y4b) ; ; Measure NO of aperture of the cylinder body when real work.
1, NO.
2, NO.
3, NO.
The coordinate of position of weak opening center of 4 is respectively (Δ X1, Δ Y1) , (Δ X2, Δ Y2) , (Δ X3, Δ Y3) , (Δ X4, Δ Y4) , be measured each the central position coordinate of real work aperture is type of Yib of Δ of Yi- of Δ of Yi= of Δ of Xib of Δ of Xi- of Δ of {Δ Xi= respectively in, i=1, 2, 3, 4. The Xib of Δ of coordinate of position of weak opening center of the standard aperture, aperture that be measured, Δ Yib, Δ Xi, Δ Yi(i=1, 2, 3, 4) presses measurement technique of position of weak opening center and type respectively (1) computation. According to industry standard, engine the position of aperture of 4 cylinder body spends a definition to be: NO of cylinder body aperture.
2, NO.
3, NO.
The central position of 4 is relative at with NO of cylinder body aperture.
The 1 the biggest change that is fiducial good place is measured. Press this definition, it is opposite that the position of cylinder body aperture is spent at aperture NO.
1, namely aperture No.
2, No.
3, No.
The position of 4 is relative at aperture No.
The deflection of 1 center position is measured, be equivalent to checking good translation to make its center position and NO of cylinder body aperture.
After the central position coincide of 1, the deviation of position of each aperture center, namely in type of Y1 of Δ of Yi- of Δ of Yi= of δ of X1 of Δ of Xi- of Δ of {δ Xi= , i=2, 3, 4. Criterion I the position error of aperture is Ei= √ (I=2, 3, the position of group of aperture of this cylinder body of Y2i of δ of 4) δ X2i+ is spent for Ø=2eimax(i=2, 3, the seat of aperture of cylinder body of 4 crocks of engine that 4)4 epilogue develops according to measuring a principle originally spends special measuring instrument, as engine cylinder body integrated precision measures a component of machine, apply successfully already at engine cylinder body full automatic on product line. The use of this measuring instrument can raise what position of cylinder body opening spends to detect significantly precision and examine efficiency, make to assuring engine it is quality, important to raised productivity to rise action. Should measure a principle to be able to popularize application to measure a situation at other position alignment error likewise. CNC Milling
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