Raise gyro wheel law to measure the research of big diameter precision
- source:TECHEN CNC Machining
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.
When the 2 attrition force that reduce gyro wheel axis should roll round of roll, gyro wheel axis and bearing should produce clash, this attrition force is affecting the rotational situation of gyro wheel directly, we hope Yue Xiaoyue of this attrition force is good, achieve reduce slippery the goal that miss. Because this chooses attrition,dinky air bearing is idealer, then our design and the structure that conceived gas surplus tip, if pursue,4 are shown. The tip makes voidance heart, can aerate, below two end connect high-pressured gas respectively on. Kong Shijie is used to spread way in the graph. When compressing air to be entered by top center Kong Tong, it can spill over by clearance. Tip having one with the tip is a course paragraphs small abrade and those who become, below the static state two walls join closely, connect when gas fashionable, two tips produce minim depart because of aeriform pressure, form cone-shaped clearance, the tip of others with the tip, angle has dinky difference, form wedge clearance. Fluctuation tip uses same pressure air feed, of gyro wheel self-prossessed the air gap that makes leave a center is less than on tip, the aeriform flow that accordingly next tips spill over is little, go up top flow is large. On the other hand high-pressured gas enters gas antrum through Kongshi restrictor, fluctuation tip uses the restrictor of identical structure, the obstruction of body of convection take offense is identical. The pressure that restrictor generates falls to become direct ratio with aeriform discharge, the pressure that place above carries restrictor falls big, the pressure of the lower end falls small, go up namely force of internal pressure of the antrum that carry gas is small, and muscularity of internal pressure of antrum of lower end gas. There is pressure to differ inside gas antrum up and down, this pressure difference and air feed pressure are concerned, when air feed pressure achieves some to be worth, what this pressure differs action to be equal to gyro wheel in the active force on the tip is self-prossessed, can have gyro wheel surplus. As a result of the existence of air gap, the attrition that the body comes from since gyro wheel roll is dinky, because this can say,use structure of gas surplus tip commonner than using bearing is decreasing slippery broke a respect to advance again one pace. Graph 2 data collect diagram of structure of 4 air cushion data is collected comprise by two parts, measure be measured the revolution N of a revolution N and gyro wheel. Talk how to get be measuringed above all revolution N. Be being measured flank makes one number, when this mark passes photoelectricity switch, photoelectricity switch will receive a smooth pulse, workpiece every turn switch of a week photoelectricity can receive signal of a pulse, evacuation of enlarge of changeover of photoelectricity of this signal classics, circuit, plastics has count into the computer, the revolution N of workpiece is come down by the record so. From type (1) be pleasant to the eye piece, the N encircling number that gyro wheel place turns and be measured a diameter having immediate concern, because this rolls cycle to count N to want do one's best to be measured accurately, used Mo Er to measure a technology so. Install one round grating on gyro wheel axis, roll cycle a week, grating also turns a week. Press in front of of round grating installed floodlight bubble, lens and demonstrative grating, installed photoelectricity autodyne at the back of of round grating, formed mobile Mo Er stripe when gyro wheel and grating are rotational so. The week reticle that is like grating is 10 800 if, by Mo Er the property of stripe is knowable: Grating every turn a week has 10 800 pulse output. When the computer receives the first pulse of workpiece, begin to have count to mobile Mo Er stripe, when the 10th pulse of workpiece arrives, show 10 weeks to workpiece already turned (take 10 weeks to measure precision for the sake of rising) , stop computation of Mo Er stripe right now. Will the mobile amount of the Mo Er stripe of place plan is taken out from inside the computer, except with 10 800 it is gyro wheel place namely the circle that turn counts N. The record of signal of Mo Er stripe that if make the computer can accurate,the revolution of ground general workpiece and grating place produce comes down, photoelectricity changeover and circuit enlarge are indispensable, the pulse signal that receives because of photoelectricity autodyne is weaker and it is imitate change quantity, and what the computer can accept is digital amount, because this needs to undertake signal enlarge, and imitate signal change is digital signal. Signal magnifies we were used relatively commonly used turn over circuit of photograph scale enlarge, this circuit structure is simple, because voltage suffers the effect of feedback, resistance of input, output is very little, the ability that takes load so is stronger. Measure to get a number additionally, build with 555 time chip receive and become Schmidt trigger. The advantage of this circuit depends on: The changeover n when ① inputs signal to rise from low n and the changeover n from tall n drops are different, in order to increase the interference rejection capacity of circuit. ② undertakes in circuit condition is changed when, through circuit process of internal make a present of of positive and negative makes the edge that outputs voltage weaveform becomes very steep. Use these two characteristics to be able to change edge not only slow imitate signal (sine signal) plastic is the rectangular wave with abrupt edge, and can be in overlay the tall, low n of signal of rectangular wave pulse keeps clear of effectively. With sheet piece machine undertake computation can make circuit simplifies greatly, because of 8031 sheet piece machine interior has two to time / tally, namely T0 and T1. T0 and T1 job let be in in software process designing computation means. T0 uses the revolution N that records workpiece, t1 records amount of mobile Mo Er stripe, the pulse number that records when T0 is 10 hind, stop the computation of T1 immediately, immediately takes out the count of T1, with type (1) the diametical D of cipher out workpiece. Serve as sheet with 8255 A additionally piece the collateral interface of machine sends LED to undertake indication the diametical D of cipher out. Among them the A mouth of 8255 A and C mouth all regard output as the mouth, a mouth uses as of LED paragraph accuse, c mouth uses as accuse. 3 programming had afore-mentioned hardware, the computation that finish and operation until show diameter of the workpiece that be measured to rely on a program to come true with LED. The mobile amount that computation is pair of Zhou Shu that place of the work that be measured turns and the Mo Er stripe that arise by grating has a record. The mobile amount of the Mo Er streak that gives by the record but cipher out is measured the diameter of workpiece. Graph 5, graph 6 give priority to flow chart of program flow chart and computation program respectively. Graph flow chart of 5 main programs pursues 4 conclusion check flow chart of 6 computation program traditional gyro wheel method is online measure big diameter, raise precision measure effectively through adopting, its are measured precision and repeatability and do not adopt these measure photographs to compare, all can raise an amount level. Use gyro wheel method so online measuring big diameter still is a convenient, effective method. CNC Milling CNC Machining