# Raise gyro wheel law to measure the research of big diameter precision

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Equipment of tool of foreword 　 large scale computer, if hydraulic turbine, turbine, large generation set, large bearing is encircled,wait, often need big to its diameter to undertake high accuracy is measured, in order to satisfy the to diametical dimension control in treatment process. Big diameter is measured must solve with small measure big, online measure wait for a series of special problems. The method that uses at present has: ① undertakes metrical with π feet, although the method is simple, but measure an error bigger, precision rises very hard. ② uses large callipers to undertake metrical, if callipers adds a general along with the accretion of the diameter that be measured to be able to appear a lot of difficulty that overcome hard. ③ electron callipers is measured although precision is taller, but measure range finite still. ④ coordinate machine is a kind of more advanced measurement technique, but price of large coordinate machine is very high, and disadvantageous and online measure. ⑤ uses gyro wheel to measure be measured circumference, next cipher out its diameter, the geometrical dimension that the advantage of this method depends on the workpiece that be measured is unlimited, can with small measure Dabingke to undertake conveniently online measure, this also is come a few years, the account that was not abandoned by people from beginning to end is in. Gyro wheel law from theoretic telling do not have principle error, but as a result of the technology not attain perfect, slip like what did not solve good gyro wheel and contact of the workpiece that be measured to nod miss an issue, to measure brought an error, restricted what its measure precision to rise. What how settle gyro wheel and point of contact of the workpiece that be measured is slippery miss an issue, it is the key that perfects this technology. The principle that law of 1 gyro wheel measures principle and the standard of measure gyro wheel that raise precision to measure big diameter is shown 1 times like the graph. It is the round circumference that uses gyro wheel to measure a workpiece that be measured, the function that uses round circumference and diameter concerns, will beg through computation go out to be measured diameter namely: D=L/ π pursues law of 1 gyro wheel measures a diameter among them L is be measured a circumference, can see be measured diametical D its precision depends on be measured the measurement of a circumference, when be being measured accordingly, gyro wheel should with constant pressure and be measured a contact, thrust makes sure gyro wheel is measured relatively make without slip pure scroll. Should be measured a roll when, the transmission concern of it and gyro wheel is: 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of D=(n/N) D of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of 　 of D of π of D=N of N π (in 1) 　 type: N is gyro wheel revolution; N is be measured a revolution; D is gyro wheel diameter; D to be measured the law measures a diametical gyro wheel better land solved the diameter with small measure big question, and just facilitate online detect. But premise condition is: Be measured (weigh workpiece below) when turning with gyro wheel, should be not to have slip pure scroll between them, did not slip namely miss an appearance. But slip missing an appearance is the issue that gyro wheel law measures big diameter to let people place perplex all the time, also be relatively scabrous problem. For this, we took a few step on this kind of measurement technique, slip in order to reduce the generation that miss. 1.

1 solve be measured an axis and gyro wheel axis are installing the rough travel issue in the process to be measured workpiece and gyro wheel are installing the both axis in the process to answer mutual parallel, if pursue 2 (A) be shown. Graph axis of 2 gyro wheel and be measured an axis is not parallel when be being measured so only to measured effect, ability makes sure they are in each radial is sectional it is rotational inside same plane. If not plan two rounds between pressure is out of shape, the contact between them is point contact, if pursue,1 medium A is nodded. Because be right,boil, their rotational linear velocity is so identical, and turn inside same plane again, because this is nodded in A, the relative speed of gyro wheel and workpiece is 0, the arc length that they had turned each other are equal, the specification did not slip miss an appearance, measure the diameter that gives work accurately. But when installing workpiece and gyro wheel, workpiece axis and gyro wheel axis may do not have strict parallel, gyro wheel axis is opposite workpiece axis deviate certain angle θ , if pursue 2 medium (B) and (C) . Because the roll of workpiece is,offer by actuating device, and the roll that the roll of gyro wheel relies on workpiece, as a result of the rough travel of two axes, when workpiece and gyro wheel are turning, not be rotational inside same plane, the rotational rate that causes them is not same, from the graph of 2 (B) and (C) be pleasant to the eye piece: The rotational rate that V rolls gyro wheel of 　 of θ of =v labour Cos will be less than the rotational speed of workpiece, slippery break arise from this. The arc length that they had turned no longer equal. Measure the diameter that go out decrescent. If design orgnaization of a fine tuning, let gyro wheel axis swing around as parallel as workpiece axis position, the angle θ between gyro wheel axis and workpiece axis is bigger, measure the workpiece diameter that go out smaller. Adjust fine tuning orgnaization, make θ contend is reduced gradually, measure the workpiece diameter that go out to greaten gradually. When θ = 0, two axes are parallel, measure the diameter that go out the biggest, continue to adjust fine tuning orgnaization to make θ horn increases to the way that return, measure the diameter that go out to be reduced subsequently again, if pursue,3 are shown. Should measure the diameter that go out to be only the biggest when, explain right now gyro wheel axis and workpiece axis are parallel, the great value position in pursueing namely. Will roll axle installation to be able to avoid to slip in this position positional generation. Graph the included angle θ between axis of 3 gyro wheel and workpiece axis is right the effect that measures a diameter 1.