CN101046420A - On-line detection method for transmission torque required by PFC (Power factor correction) of mechanical press - Google Patents

Abstract

The invention discloses an on-line detection method for the transmission torque required by PFC (power factor correction) of a mechanical press, which adopts a slider force range indirect measurement method to detect the torque required by PFCTransmitted torque M_aObtaining M by adopting the force stroke characteristic of the slide block according to the relevant information of the actual processing of the mechanical press_aThe method of (2) was studied. When the required torque M of the crankshaft is obtained from the force path characteristics on the slide_RaThereafter, M can be conveniently determined by the formula_aThe values of (3) are measured on line by utilizing a force sensor, an A/D board, a computer and the like to measure the deformation force value and the moment thereof, and the torque M at different moments in the workpiece deformation stage can be automatically calculated by adopting software_RaAnd outputs M at different times_RaValue and maximum value M_RmThe method has the good characteristics of rapidness, reliability and the like, and can be popularized and applied in production.

Description

The online test method of process of transfer torque mechanical press PFC requires

Technical field

The invention belongs to the transmission moment of torsion detection method in the punching machine field of forging equipment, be specifically related to the online test method and the device of the required transmission moment of torsion of a kind of PFC.

Background technology

When punching machine is forged towards work, need air operated friction clutch (PneumaticFriction Clutch is hereinafter to be referred as PFC) friction pair can export enough big moment of torsion M _q〉=M _a, otherwise the generation of PFC rubbing surface is skidded and vexed car accident is taken place.Provide suitable air pressure to satisfy M for the PFC cylinder by electric proportional pressure valve _q〉=M _aThe operate as normal requirement, must know M in advance obviously _aSize.

At present in all punching machines at home and abroad, no matter workpiece deformation needs PFC to transmit great moment of torsion M at every turn _a(upset force that carries out the 1st work step as the gear hot forging often only is 1/3 of the 2nd a work step finish-forging power, the required M of corresponding the 1st work step _A1Less than the 2nd work step 1/2), but each PFC cylinder all advances maximum air pressure p _Max, correspondingly the PFC moment of torsion that can provide always is maximal value M _Qmax, not only caused the waste of compressed air energy but also made the exhaust noise of PFC increase pollution grows worse environment, therefore the invention provides the method that a kind of size of the moment of torsion to the required transmission of PFC is carried out on-line measurement.And discussed in detail and how to have detected the moment of torsion M that obtains the required transmission of PFC by this measurement mechanism _a, PFC is again how according to M _aSize, enough big moment of torsion M is provided _qThe needs that the work of satisfying is out of shape.

Because the complicacy of plastic history and punching machine is brought when big difficulty to Theoretical Calculation, adopts the method for online actual measurement to determine M here for this reason _aSize, usually the useful torque sensor of method of testing of actual moment of torsion is directly measured, is used load sensor to measure, use motor current to measure indirectly indirectly and utilizes the slide block range to measure four kinds of methods indirectly on the PFC axle, and this paper discusses respectively these four kinds of methods earlier.

1. torque sensor direct measuring method

The sensor of directly measuring moment of torsion on the rotation axis has following two types:

A. strain-type torque sensor:

Adopt resistance strain gage mechanical strain to be converted to the electric signal that is proportional to moment of torsion.Because its output signal from the rotating shaft, device is complicated, or poor reliability or cost are too high, use inconvenience.

B. torsion angle phase-difference type torque sensor

Torque measurement principle as JCZ type torque rotary speed sensor is exactly the phase-difference type principle, promptly two signal gear are installed at the two ends of elastic shaft, one group of signal coil respectively is housed above two gears, the magnetic cylinder all is housed in signal coil, form the magnetoelectricity signal generator with signal gear.When signal gear is rotated with elastic shaft, because the tooth top of signal gear and the bottom of the inswept magnetic cylinder of tooth paddy alternate cycle, make air-gap permeance produce periodic the variation, the magnetic flux of coil inside also produces cyclical variation, makes the ac signal that generates the near sinusoidal ripple in the coil.When elastic shaft is turned round, will produce torsional deflection, two groups of phase differential between the ac signal are changed, in regime of elastic deformation, the absolute value that phase differential changes is directly proportional with the size of torque.

The industry spot environment that forging and pressing are produced is abominable, and should not carry out the destructive transient equilibrium (as sensor installation on bent axle and annex thereof) of handling (as in polishing, boring etc. on the bent axle) and destroying bent axle to the bent axle of punching machine, therefore, the method for the moment of torsion on the above-mentioned direct measurement rotation axis is used difficulty in punching machine FPC torsion-testing.

2. load sensor is measured torque method indirectly

Installing on punching machine and using load sensor all is eaily, and the load sensor of installation then can be measured moment of torsion on the PFC axle and the variation relation of time on the PFCB-82 type punching machine air operated friction clutch of Xi'an Communications University's mould and plastic working research institute and detent comprehensive intelligent testing table (as shown in Figure 1).Fig. 2 is the situation of installed load sensor on this experiment table, two boss about the holder of detent has, and at a side installed load sensor, the power of the output by measuring load sensor is by torque arithmetic formula M _a=F * L indirect calculation obtains acting on the moment of torsion on the PFC axle.

3. torque method on the indirect measurement axis of motor current

Punching machine is generally driven by threephase asynchronous, and when moment of torsion required on the PFC axle was big more, the then corresponding required output torque of motor was also big more, can extrapolate M on the PFC axle indirectly by the measurement result to motor output torque like this _aBy the operation logic of asynchronous motor as can be known, the electric current in the rotor winding has produced the electromagnetic torque that acts on the motor rotor under the effect of rotating magnetic field.Learned as can be known by motor, the average electromagnetic torque M of motor is:

M＝K·Φ _m·I ₂·cosΦ ₂(N·m) (1)

In the formula: the coefficient of K-and electric motor structure relating to parameters is called moment coefficient;

Φ _mThe every utmost point magnetic flux of-air gap (Wb);

I ₂-rotor winding phase current (A);

Cos Φ ₂The power factor of-rotor winding

Can find out the every utmost point magnetic flux phi of the size of asynchronous motor electromagnetic torque M and air gap by formula (1) _m, rotor phase current I ₂And the power factor cos Φ of rotor ₂Be directly proportional.But because this concerns more complicated, and in actual production, the revolutional slip of motor was very little when motor turned round in normal range, its air-gap flux Φ _mCan be considered ratings, power factor cos Φ ₂≈ 1, like this size of electromagnetic torque M only with rotor current I ₂Be directly proportional.But,, after respectively amount is carried out amounting to of the number of turn, the number of phases and rotor-position rotor, can obtain stator current according to the equivalent circuit of motor because rotor current is not easy to measure

Rotor is amounted to electric current

Exciting current with motor Relation:

${\stackrel{\·}{I}}_1={\stackrel{\·}{I}}_2^{\′}={\stackrel{\·}{I}}_0...\left(2\right)$

In the formula ${\stackrel{\·}{I}}_2^{\′}=\frac{{\stackrel{\·}{I}}_1}{k_i},$ k _iBe the electrorheological ratio, can be by calculating or the experiment acquisition.Asynchronous motor in the normal range of operation from the zero load to the nominal load, exciting current

Variation also very little, can be considered definite value basically.Therefore by formula (1) and (2) as can be known, the electromagnetic torque of motor and stator current have certain proportionate relationship, can be by the electric current of a certain phase in the measurement motor stator, and the electromagnetism that record motor is indirectly exported torque.Find that through a large amount of experiments on experiment table the size of current of motor is not only relevant with its output torque, and relevant with technology type, so the present invention does not adopt the method to obtain M _aValue.

4. slide block range indirect measurement method:

The moment of torsion M of the required transmission of PFC of punching machine in the reality _aRequired power and Deformation Height are determined when making workpiece produce distortion by its slide block by mould, the device of automatic detection forging towards deformation force and Deformation Height is installed on some punching machine in commercial production reality, like this, the moment of torsion M that just can obtain to act on the bent axle with the size of these two kinds of signals _Ra

M _Ra＝Pm _q (3)

P is the workpiece deformation power (N) that affacts on the slide block in the formula, m _qThe equivalent arm of force (m) for toggle.

The moment of torsion M that on online known bent axle, acts on _Ra, the moment of torsion M of required transmission on the PFC axle correspondingly _aShould be

$M_a=\frac{M_{\mathrm{Ra}}}{\mathrm{i\η}}...\left(4\right)$

In the formula i be the axle of PFC to the ratio of gear of bent axle, η be the PFC axle to the transmission efficiency between the bent axle, to one-level gear drive η=0.97, secondary gear transmission η=0.94.

Summary of the invention

The objective of the invention is to, a kind of online test method of process of transfer torque mechanical press PFC requires is provided, this method is exactly to adopt above-mentioned the 4th kind of method to come moment of torsion actual on the on-line testing PFC axle to determine M _aSize.

In order to realize above-mentioned task, the present invention takes following technical solution:

A kind of online test method of process of transfer torque mechanical press PFC requires, this method adopt the slide block range indirect method of measurement to detect the moment of torsion M of the required transmission of PFC _a, it is characterized in that, specifically comprise the following steps:

1) the moment of torsion M that can provide with PFC _q=β M _aAnd M _qBecome good linear relationship M with cylinder air pressure _QC=kp, the air pressure p that enters the PFC cylinder by adjusting reaches the control of the moment of torsion that can produce PFC;

2) utilize slide block range curve to determine required transmission moment of torsion M on the PFC rubbing surface _RaMethod, comprised maximum distortion power P by technology type _mWith by online actual measurement P-t numerical relation dual mode;

A. adopt by technology type and maximum distortion power P _mMode determine moment of torsion M _RaThe time, at first should set up the technology of the finishing mathematic(al) representation of workload characteristics comparatively accurately, calculate the peak torque M of each section in the workpiece deformation process then _Raim, obtain moment of torsion maximal value M in the whole deformation process by the contrast of each section at last _Rm

B. adopt by online actual measurement P-t numerical relation and be, utilize force transducer, A/D plate and computing machine online actual measurement deformation force numerical value and the moment thereof, computing machine is controlled by data acquisition and output card, adopts software can calculate workpiece deformation different moment of torsion M constantly in the stage automatically _Ra, and the different M constantly of output _RaValue and maximal value M _Rm

For the correctness of the relative program of verifying method of the present invention, the typical process when selecting for use the JH23-63 type punching machine of Shanghai second Casting Machine Tools Plant production to finish cold extrusion is studied.Suppose P in certain cold-extrusion technology _m=3 * 10 ⁵N, α ₀=30 °, the parameter of this punching machine is ram travel s ₀=100mm, crank length R=s ₀/ 2=50mm, d _o=115mm, d _A=155mm, d _B=120mm, μ=0.045, λ=0.1, Δ α=1 °, ε=0.5 °, ratio of gear I=5.353 (distinguishes for ease of the i in increasing with angle, change the bent axle in the formula (4) into alphabetical I here to the ratio of gear i between the PFC axle), one-level gear-driven efficiency η=0.97, ram travel frequency n=50 time/minute, corresponding crank angular velocity of rotation is ω=2 π n/60=5.236 (rad/s), through the result after calculating as shown in Figure 3, for intuitively, horizontal ordinate is represented M ' among the figure with pressure angle α (angle) _l, M ' _μBe respectively desired torque and the resistance moment of torsion converted on the PFC axle.

Description of drawings

Fig. 1 is PFC-B-82 type punching machine air operated friction clutch and detent comprehensive intelligent test platform structure synoptic diagram.：1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24.25. 26. 27.；

Fig. 2 utilizes load sensor test axle to go up the structure of moment of torsion;

Fig. 3 is by P _mAsk for the change in torque family curve of cold-extrusion technology, wherein curve a is M _a, curve b is M ' _l, curve c is M ' _μ

Fig. 4 is the computing machine on-line monitoring and the control system of process of transfer torque mechanical press PFC requires;

Fig. 5 is the deformation force family curve of online actual measurement;

Fig. 6 is the change in torque curve in the drawing work of line computation;

Fig. 7 is a drawing work deformation force change curve.

The present invention is described in further detail below in conjunction with accompanying drawing.

Embodiment

As previously mentioned, make the moment of torsion M of PFC friction pair output _qCan satisfy the requirement of workpiece deformation, the moment of torsion M that required PFC rubbing surface transmits in the time of just must knowing this workpiece deformation _a, could realize M like this according to the required transmission of PFC _a, by intelligentized pneumatic system so that the moment of torsion that the PFC friction pair can be exported satisfy: M _q〉=M _a, realize that adaptively reliable, high-effect, oligosaprobic forging is towards processing.The present invention comes to determine M for information about according to the actual processing of punching machine _aValue.Obtain M _aMethod a lot, the present invention only just adopts slide block range characteristic to obtain M _aThe method of value study.As the required torque M that obtains bent axle by the range characteristic on the slide block _RaAfter, can determine M by formula easily _aValue, for this reason, the present invention is only with regard to M _RaBe how to determine to study.

The device (being designated hereinafter simply as device for measuring force) that can detect automatically and show the workpiece deformation power that acts on the slide block has been installed on some punching machine in industrial reality.Present this device for measuring force has two kinds of way of outputs, and a kind of is only to export and to show maximum workpiece deformation power P _m, another kind is the size of exportable different deformation force P constantly, and provides maximal value, promptly exportable and demonstration P-t numerical value and curve.For this reason, the present invention is at first known but device for measuring force only can be exported maximum workpiece deformation power P to technology type _mSituation under how to obtain M _RaStudy, obtain M under the situation to known P-t successively then _RaValue discuss.

1.PFC moment of torsion and the relation of air pressure size

The front has been narrated in the punching machine course of work, how to obtain the moment of torsion M on the PFC axle online _aMethod.At known M _aSize after, ensuing problem is exactly to allow the friction pair of PFC that enough big moment of torsion M can be provided _q, make M _q〉=M _a, skid otherwise will rubbing surface take place in the workpiece deformation process, friction material wearing and tearing, overheated, even serious " vexed car " accident takes place.But if no matter M _aSize, all get maximal value M when working at every turn _QmaxThough reliable operation can cause the waste of great compressed air energy as previously mentioned, this is the deficiency that present PFC air-channel system exists, and also the present invention will improve part just.

Consider to have fricting movement resistance moment of torsion in the course of work, for operate as normal M _q〉=M _a, but for energy-conservation again can not be a lot of greatly, be defined in here when carrying out the moment of torsion Based Intelligent Control and get:

M _q＝βM _a (5)

β is defined as the PFC coefficient of torque reserve in the formula.It is to consider the moment of torsion M that can transmit between the PFC friction pair _qBe subjected under the situations such as variation of the stability of fluctuation, the friction factor of PFC cylinder internal gas pressure, true rubbing contact area the PFC operate as normal being obtained.Here get β=1.1～1.3, the application gets β=1.2.

To the PFC friction pair, the moment of torsion M that it can be exported _qShould be

M _q＝mμqF ₀R _μ (6)

In the formula, m is the rubbing surface number, and μ is a friction factor, to the common employed friction material of punching machine and to mill element μ=0.3～0.4.R _μBe equivalent friction radius of facing, F ₀Be the single-sided friction area, q is the specific pressure on the rubbing surface, and the total snap-in force Q that acts on this rubbing surface is

Q＝qF ₀ (7)

Q is normally produced by the piston in the cylinder, and piston is to rely on compressed air-driven, and ought establish the PFC piston area like this is S, and pressurized air pressure is p, when the friction ignored between piston and the cylinder, can get:

Q＝pS (8)

Because μ, F, R in formula (6) and the formula (8) _μAnd very difficult artificial adjusting of S, so as can be known by formula (5), in order to make M _qCan follow M _aAnd change, can only be by regulating the size of air pressure p.The size of air pressure p in this application, air pressure p relies on the online adjusting of electric proportion magnetic valve in this article, thereby comes the detection feedback debug results to constitute closed-loop system by baroceptor.

Usually the friction pair form of PFC has disc type and two kinds of the formulas of inserting of floating.The unsteady formula version of inserting that PFC-B-82 type testing table among the application adopts, its friction torque that can produce is

M _q＝2μqzF _iR _μ (9)

In the formula: z is the number of inserting that floats;

F _iIt is a monolateral friction area of floating and inserting.

That is to say, this kind floated inlay fast structure, have following formula

F ₀＝zF _i (10)

m＝2 (11)

Can get by formula (7)～(11):

M _q＝2μpSR _μ (12)

In experiment of the present invention, PFC and PFB rubbing surface are of a size of z=10, R _μ=0.210m, μ=0.3～0.35, F _i=7.7117 * 10 ^-3m ², S _B=0.2366m ², S _C=0.2686m ²S wherein _B, S _CBe respectively the area of PFC and PFB piston.

With above-mentioned data substitution formula (12) and get μ=0.31 and can get:

M _qB＝0.0308p(N·m) (13)

M _qC＝0.0350p(N·m) (14)

As seen the PFC to other size still exists

M _qC＝kp (15)

That is to say that the interior air pressure size of friction torque size that power clutch can produce and cylinder is directly proportional, by formula (5) and formula (15) as can be known, directly detecting the friction torque M of the required transmission of PFC like this _aSituation under, can be according to M _aAnd the size of regulating the cylinder internal gas pressure, thereby reach the purpose of save compressed air.

2. use the slide block range characteristic of online actual measurement to determine M _a

By document as can be known, when known workpiece deformation power P, also can't determine to affact the moment of torsion M on the bent axle _Ra, must know the size of the arm of force, at maximum distortion power P _mOften locate the arm of force and may not get maximal value, relation between the two exists than big-difference different technology.Expect M _RaValue, must know any arm of force length m _qUnder deformation force P, both multiply each other and could obtain M _RaValue, could try to achieve M on the PFC axle by formula (4) then _aThe M of any time now _RaValue can't be known and only know P _mValue, how to obtain M _Ra?

Though the P of any time can't obtain, the technology type that punching machine reality is finished is to determine as stamping-out, pull and stretch, hot forging, cold extrusion, and every kind of technology all has its unique range characteristic, especially at known P _mDuring with Deformation Height, the deformation rule of other power constantly can calculate out that the workpiece deformation height here also is known to machining blanks and the mould of determining, so just at already known processes type, P _mAnd under the h situation, just can obtain the M of any time _RaValue can find out that thus there is certain approximation in this method.

For this reason, the present invention discusses the distortion range rule of different process type earlier, and then how research determines M by the distortion range of already known processes _RaAs previously mentioned, because M _RaKnown, by formula (4) as can be known, M _aJust can try to achieve, so how following only research obtains M _Ra

According to document, after the consideration rubbing action, the moment of torsion of the required transmission of the bent axle of punching machine (or eccentric wheel) can be expressed as:

M _Ra(α)＝M _l(α)+M _μ(a) (16)

$M_l\left(\mathrm{\&alpha;}\right)=P\left(\mathrm{\&alpha;}\right)R(\sin \mathrm{\&alpha;}+\frac{\mathrm{\&lambda;}}{2}\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="A20071001776000161.png"\; state="\{\{state\}\}">sin</figure-callout>}2\mathrm{\&alpha;})/\cos \left({\sin }^{-1}\left(\mathrm{\&lambda;}\sin \mathrm{\&alpha;}\right)\right)...\left(17\right)$

$M_{\mathrm{\&mu;}}\left(\mathrm{\&alpha;}\right)=\frac{\frac{1}{2}P\left(\mathrm{\&alpha;}\right)\mathrm{\&mu;}[(1+\mathrm{\&lambda;}\cos \mathrm{\&alpha;})d_A+\mathrm{\&lambda;}{d}_A\cos \mathrm{\&alpha;}+d_o+2\mathrm{\&lambda;}R\sin \mathrm{\&alpha;}(\sin \mathrm{\&alpha;}+\frac{\mathrm{\&lambda;}}{2}\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="A20071001776000161.png"\; state="\{\{state\}\}">sin</figure-callout>}2\mathrm{\&alpha;})]}{\cos \left({\sin }^{-1}\left(\mathrm{\&lambda;}\sin \mathrm{\&alpha;}\right)\right)}...\left(18\right)$

M in the formula _l(α) be desired torque, M _μ(α) be friction torque, P (α) is a workpiece deformation power, and μ is a mechanical rotation system friction coefficient, and opposite opened pressing machine μ=0.04～0.05 is to straight side press μ=0.045～0.055, d _A, d _BAnd d _oBe respectively the diameter of connecting rod tip, small end and crankshaft support axle journal.Consider that aforementioned five kinds of typical process constitute by the broken line of Different Slope, have more versatility for making P (α) expression formula, with reference to the discussion of aforementioned each technology range characteristic equation, P (α) can be write as:

P(α)＝k(α-a ₀)+P ₀ (19)

K=(P in the formula ₁-P ₀)/(a ₁-a ₀) be the slope of load line segment; (a ₀, P ₀) and (a ₁, P ₁) being respectively the coordinate of this line segment two-end-point, this coordinate of 2 is determined by the parameter of each typical process, in concrete solution procedure, needs determine this coordinate of 2 according to technological parameter earlier, could further find the solution then.

For the convenience of subsequent calculations, can make:

$f_1\left(\mathrm{\&alpha;}\right)=R(\sin \mathrm{\&alpha;}+\frac{\mathrm{\&lambda;}}{2}\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="A20071001776000161.png"\; state="\{\{state\}\}">sin</figure-callout>}2\mathrm{\&alpha;})/\cos \left(\arcsin \left(\mathrm{\&lambda;}\sin \mathrm{\&alpha;}\right)\right)...\left(20\right)$

$f_2\left(\mathrm{\&alpha;}\right)=\frac{\frac{1}{2}\mathrm{\&mu;}[(1+\mathrm{\&lambda;}\cos \mathrm{\&alpha;})d_A+\mathrm{\&lambda;}{d}_B\cos \mathrm{\&alpha;}+d_o+2\mathrm{\&lambda;}R\sin \mathrm{\&alpha;}(\sin \mathrm{\&alpha;}+\frac{\mathrm{\&lambda;}}{2}\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="A20071001776000161.png"\; state="\{\{state\}\}">sin</figure-callout>}2\mathrm{\&alpha;})]}{\cos \left(\arcsin \left(\mathrm{\&lambda;}\sin \mathrm{\&alpha;}\right)\right)}...\left(21\right)$

Like this, formula (17) and (18) can be write as respectively:

M _l(α)＝P(α)f ₁(α) (22)

M _μ(α)＝P(α)f ₂(α) (23)

Again convolution (16) as seen, M _Ra(α) be function, can use a computer easily by formula (16) and (19)～(23) like this and obtain M about α _RaValue (α) also obtains its maximal value.In addition as can be known, for each section of range figure, M by the range figure of each typical process in the pertinent literature _q(α) all continuous, promptly each section all has extreme value to occur, and this extreme value is the maximal value of the moment of torsion of this section.

Because to PFC output torque M _qBased Intelligent Control be online in real time, so require fast automaticly P according to online actual measurement gained _mValue and the technology type output M that is finished _RaValue, be convenient to system is controlled.Therefore must the online M that tries to achieve of programming _RaValue, and then obtain M by formula (4) _aValue.

According to technique scheme, the on-line monitoring system of process of transfer torque mechanical press PFC requires of the present invention adopts computing machine by data acquisition deformation force sensor signal, utilizes the P-t numerical relation of online actual measurement to determine M _RaBe illustrated in figure 4 as the computing machine on-line monitoring and the control system synoptic diagram of process of transfer torque mechanical press PFC requires.

As previously mentioned, the simulating signal of the deformation force P value of deformation force sensor exportable any time of installing on some punching machine just can obtain the P-t data relationship by A/D data acquisition and computing machine.Consider α=ω t, through time t being converted into the P-α relation and the numerical value that just can obtain after the crank angle concerns α and digital filtering as shown in Figure 5.Just discuss below and how to determine M by Fig. 5 _RaSize.

3. corner step delta α's chooses

At first to as [α between the Microcell among Fig. 5 _i, α _I+1], α _I+1=α _i+ Δ α, Δ α is for calculating M _RaStep-length, between this Microcell in, establish P and change very I and ignore, thereby can regard constant as, and get the numerical value P that does left side between microcell _i, i.e. P=P (α _i) (α _i≤ α≤α _i+ Δ α).Continuous curve among Fig. 5 just can be by the different ladder (α of height like this _i, P _i) replace, in fact when computing machine obtains curve among Fig. 5 by the A/D card, also be smooth and get by very intensive discrete point.Think the curve (the situation exception that has P-α Presentation Function certainly in control system) that improves arithmetic speed and also can obtain Fig. 5 earlier, when the sampling period of known A/D card Δ t, calculated torque M _RaThe time corner step delta α can choose by following formula:

Δα＝ωΔt (24)

Δ α is more little obviously, and degree of accuracy is high more, but the real-time of On-line Control moment of torsion can be subjected to influence to a certain degree, so choosing of Δ α should be taken into account above-mentioned two aspects.

1.M _RaDetermine

By formula (16), (17) and (18), at arbitrary corner α _iThe moment of torsion M of required transmission on the bent axle at place _RaiFor

M _Rai＝M _l(α _i)+M _μ(α _i) (25)

M _l(α _i)＝P(α _i)f ₁(α _i) (26)

M _μ(α _i)＝P(α _i)f ₂(α _i) (27)

Increase a Δ α then, obtain next corner α _I+1=α _iThe M at+Δ α place _{Ra (i+1)}Value, carry out successively up to calculating all (0～α ₀) the interior M of scope _RaValue, relatively obtain maximal value M then _RmUtilize formula ω t again _i=α _iJust can obtain not t constantly _iMoment of torsion M _RaiValue.The above calculation procedure program of being compiled into can be implemented in line computation, and rapidly provide data for the control system of back.In order to verify this program correctness, the JH23-63 type punching machine that is used when still selecting previous exemplary for use carries out the force deformation figure of the approximate half sine-wave with typical drawing work is carried out emulation, promptly

P(α)＝4×10 ⁵sin?2α(N) (0≤α≤90°) (28)

As previously mentioned to this punching machine because of its ram travel s ₀=100mm, crank length R=s ₀/ 2=50mm, d ₀=115mm, d _A=155mm, d _B=120mm, μ=0.045, λ=0.1, Δ α=1 °, ratio of gear I=5.353, one-level gear-driven efficiency η=0.97, ram travel frequency n=50 time/minute, correspondingly crank angular velocity of rotation ω=2 π n/60=5.236 (rad/s).Above-mentioned given data is input in the program of being worked out, can obtains simulation result as shown in Figure 6 and Figure 7, Fig. 6 is the change in torque curve, and Fig. 7 is the deformation force curve.Obtain the required peak torque M of PFC axle in the time of can trying to achieve in pressure angle α=53.1 ° (t=0.177s) by Fig. 6 _a=3493 (Nm).Can find out M from Fig. 6 and Fig. 7 _aMaximal value and moment of occurring of the maximal value of power P be different (maximal values that deformation force P gets at 45 places), therefore can not think maximum distortion power P simply _mThe place is exactly the moment of torsion maximum.

Utilize online actual measurement deformation force numerical value such as force transducer, A/D plate and computing machine and constantly, adopt software can calculate workpiece deformation different moment of torsion M constantly in the stage automatically _Ra, and the different M constantly of output _RaValue and maximal value M _Rm, this method has superperformances such as rapid, reliable, is worth applying aborning.

Finished a series of tests according to the technique scheme applicant, result's proof has reached purpose of the present invention.

Claims (1)

1. the online test method of the required transmission moment of torsion of punching machine air operated friction clutch, this method adopt the slide block range indirect method of measurement to detect the moment of torsion M of the required transmission of air operated friction clutch _a, it is characterized in that, specifically comprise the following steps:

1) defines the moment of torsion M that air operated friction clutch can provide _q=β M _a, and M _qBecome good linear relationship with PFC cylinder air pressure, promptly the interior air pressure size of the air operated friction clutch friction torque size that can produce and cylinder is directly proportional, i.e. M _q=kp, wherein, M _aThe moment of torsion of the required transmission of air operated friction clutch during for the punching machine operate as normal; β is the PFC coefficient of torque reserve, and β=1.1～1.3, and the air pressure p that enters the air operated friction clutch cylinder by adjusting reaches the control of the moment of torsion that can produce air operated friction clutch;

2) utilize slide block range curve to determine required transmission moment of torsion M on the rubbing surface _Ra, comprise maximum distortion power P by technology type _mWith online actual measurement P-t numerical relation dual mode;

A. adopt by technology type and maximum distortion power P _mMode be, at first set up the mathematic(al) representation of the workload characteristics of the technology of finishing, calculate the peak torque M of each section in the workpiece deformation process then _Raim, obtain moment of torsion maximal value M in the whole deformation process by the contrast of each section at last _Rm

B. adopt online actual measurement P-t numerical relation to be, utilize force transducer, A/D plate and computing machine online actual measurement deformation force numerical value and the moment thereof, computing machine is controlled by data acquisition and output card, adopts software to calculate workpiece deformation different moment of torsion M constantly in the stage automatically _Ra, and the different M constantly of output _RaValue and maximal value M _Rm

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