GB2239108A - Vibrating workpieces - Google Patents
Vibrating workpieces Download PDFInfo
- Publication number
- GB2239108A GB2239108A GB8928301A GB8928301A GB2239108A GB 2239108 A GB2239108 A GB 2239108A GB 8928301 A GB8928301 A GB 8928301A GB 8928301 A GB8928301 A GB 8928301A GB 2239108 A GB2239108 A GB 2239108A
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- Prior art keywords
- electric motor
- vibratory
- frequency
- treatment
- speed
- Prior art date
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
- F16F15/22—Compensation of inertia forces
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
- B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D10/00—Modifying the physical properties by methods other than heat treatment or deformation
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D19/00—Control of mechanical oscillations, e.g. of amplitude, of frequency, of phase
- G05D19/02—Control of mechanical oscillations, e.g. of amplitude, of frequency, of phase characterised by the use of electric means
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- General Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Crystallography & Structural Chemistry (AREA)
- Acoustics & Sound (AREA)
- Aviation & Aerospace Engineering (AREA)
- Thermal Sciences (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Apparatuses For Generation Of Mechanical Vibrations (AREA)
- Control Of Electric Motors In General (AREA)
Abstract
To remove internal stress remaining after casting, welding etc, a workpiece 14 is vibrated by a device 1 driven by a motor 2. The workpiece is vibrated at a first resonant frequency, the frequency is adjusted to accommodate changes caused by reduction in stress and vibration at that frequency is terminated when there is no further stress reduction. In accordance with the invention, change in stress is monitored by detecting the emf induced at a bearing 10 of the motor armature - as shown by using an amplifier 5 and meter 4. The process is repeated at successive resonant frequencies until there is no change in monitored emf from one frequency to another. In the embodiment shown, a computer 13 effects the change from frequency to frequency. <IMAGE>
Description
9 -I- METHOD FOR VIBRATORY TREATA2NT OF WORKPIECES AND A DEVICE FOR
CARRYING SAME INTO EFFECT The invention relates to treatment Of metal workpieces and is Concerned more specifically with a method for vibratory treatment of WDrkpieces and to a device for carrying same into effect.
The most effective field of application of the present invention is Control Over vibratory treatment of cast or welded wDrkpieces aimed at reducing residual stresses therein.
Another field Of application Of the present invention can be Control over vibratory treatment of wDrkpieces after die-forging Or bending in Order to prevent their subsequent working.
Welded or cast workpieces are liable to defDrMS- tion under the effect Of residual stresses as times roes by after their manufacture. Even in the CDUrSe of their manufacture the dimensiDns of workpieces are likely to change to such a degree between their finishing and assembly that the dimensions Of 8 finished product fail to satisfy requirements iMPDS6d tbereon as for accuracy. Application'Df vibratory treatment enables One to stabilize geometric din-ensions Of a wDrkpiece. The most efficient results of vibratory treatment are attainable due to the use of the resonance method, wherein the wDrkpiece is treated at its resonant frequencies. Adequate efficiency Of the reso- nance method Is ensured due to higb-explitude vibratory stresses arising In tbe'wDrkpiece, which causes substantial reduction of residual stresses.
Equipment applied for vibratory treatment differs in the type of the vibration exciter used, a decisive parameter of which is the frequency range, and is classified Into equipment incorporating unbalance to 2000 Hz), electrDma-netic (20 to 1000 Hz), and electrodynamic (5 to 5000 Hz) vibration exciters.
One of the important parameters characteristic of the vibration treatment COnditiDnS is time. A required treatment ti.ie is concerned first and f oremDst with the mass of the workpiece being treated. However, no particular duly substantiated recommendations on vibration treatment time occurs at the present time, since such time depends not only on the workpiece mass but also on its structural features. the level of residual stresses in the vjDrkpiece, and a number of other factors hardly taken account of. As a rule, the length of treatment time is determined empirically.
Known in the present state of the art is a metbDd for vibratory reduction of internal stresses (US, A, 622,4,34), wherein a vibration exciter is made fasty through clamps o.-. the workpiece which Is electrically i. nsulated from the sbDP'S floor, whereupon vibrations are excited therein. A device for carrying said method -3 intD effect is provided with an unbalance-type vibration exciter with a direct-current electric motor and has a vibration fr4quencv regulatore Prior to treatment of a workpiece there is per- formed vibratory scanning of the excitation frequenCY with a view to determine resonant frequencies. Once 6 to 12 resonant frequencies have been determined, vibration treatment is carried out at 4 to 6 of such frequencies. A syrriptDm of reduction of residual stresses is a 10 to 15 percent drop of current consumed by the electric Motor durin,' vibratory treatment.
A disadvantage inherent In the aforesaid known method and in the JAevice carrying said method into affect resides in too low an accuracy of determination of reduction stresses and hence of the instant when the treatment is complated. Control over stabilization of residual stresses is effected immediately daring the treatment process awainst the current cc),-,sumed by the electric motor, However, the 8CCUr8C7 of L2easu- rement of a consumed current is affected by numerous factors concerned with energy losses, such as losses by internal friction in the material of the viorkpiece beinS treated, aerodynamic dampint, (loss b sound emission into the surrounding atmosphere, electric los.-:es (by eddy currenzs and by beazing the arw.tare winding Conductors), constructional damping at places of the vibretDr-tO-WDúkpiece contacts, as well as losses In shockabSDrbers on which the workpiece is positioned. The aforellsted energy losses are liable, to change within broad limits under the effect of extrinsic uncontrollable factors. The enerty consumed for reduction of residual stresses is measured against a background of the total energy losses which exceed the amount of energy spent for reduction of residual stresses.
The closest tUD the Method disclosed herein is a method for vibratory treatment of wDr'r-pieces (SU, A, 798,185) with the aid of an electromechanical unbalance vibration exciter connected to an electric Motor. The known method makes provision for multiply repeated vibratory excitation of the wDrkpiece beina treated at resonant frequencies of the various harmonics, followed by taking down vibratory displacements and vibromDtive forces applied, finding out the amplitudephase-frequency characteristic of vibratory excitation of the WDrkpiece involved, determining the real part of the amplitude- phase-fxequency characteristic, and cDmpletint; the treatment as soon as the zero-crossing points of said characteristic discontinue shifting, which corresponds to stabilizatiDn of the workpiece vibration fre-uency and hence to stabilization of residual stresses.
A disadvantage inherent in the known method resides in a low accuracy Df determination of the kinetics of variation of residual stresses and their stabilization, since the amplitude-pbase-frequencv characteristic of vibratory excitation is affected by the signals of adjacent harmonics, noises interferences and U12,3CCDunted vibrations.
A prior-art device for carrying into effect the afDrediscussed method for vibratory treatment of workpieces (SU, A, 798,185) is known to comprise an electromechanical unbalance vibration exciter connected to a variable-speed electric motor, a voltage converter, a measurin., instrument, t-i/D filters, a transducer of vibratory displacementus of the workpiece being treated, connected to the input of the first filter, a multiplier, a measuring instrument, a force cell seriesly connected, via the second filter, to the first inpu-c of the mul'tuiplier whose second input is connected to the output of the f irsu filter and the output, to the measuring instrument.
In the cou.-se of operation the vibration exciter sets up mechanical vibrations In the workpiece bein., treated, the work,iece excitation frequency being varied in order to attain its tuning to reSDnence, The excitation frequency is varied by ii,eens of the voltage converter. The force cell is located at the output of the vibration exciter and is adapted to -ene- a rate an electric signal proportionate to the eXCit8tiDU force. Distortions of %be excitation force pulse are rejected by the second filter. Reaction of the Work- piece to the excitation applied thereto is measured, as its vibratory displacement, by the vibratory displacement transducer with due account of the phase of the vibratory displacement signal with respect to the excitation force signal, the distortions of the vibration displacement signal being rejected by the first filter. Then the amplitude-pbase-frequency cberecteristic is established prDceedint from the presentatiDn given by the transducers, the real part of the above characteristic is determined as well as the points of crossing of the real part of the amplitude- phase-frequency characteristic of vibratory excitation through zero axis, and as soon as said crossing points cease shifting the vibration tres-Gment process is terminated.
A disadvantage inherent in said device lies with the absence of stabilizatiDn of the motor speed and of the vibration exciter rate. This is liable to disturb conditions o-' resonance, distort the amplitude -phase-frequency characteristic of vibratory excitation and impede registration of the kinetics of variation of residual stresses and their stabilizatiDn.
1 It is an object of the present invention to enhance the efficiency of vibratory treatment Of workpieces.
It is another object of the present invention to provide bighex accurecy of measurernent of the resonant frequency concerned with the kinetics of varietion of residual stresses.
It is one more object of the present invention to Provide bigher accuracy of registration Of an instant C3 when final stabilizatiDn Of residual stresses in the wDrkj.iece Occurs.
It is a further Object of the present invention to save energy spent for vibration treatment of the WD.rkpiece beinG handled and to curtail the wDrkpiece trestment time.
It is still one more Object of the present in- ventiDn to provide a possibility of full autornation of the vibratory treatment process of a workpiece.
It is yet still one more object of the present invention to provide higher output of the vibration exciter.
The forag--ing and -Urth6X Objects are accomplished due to the fact that in method for vibratory trerAment Of workpieces, consisting in multiply repeated vibratD.r.V excitation Of the iiDr&pi=-ce bein.:-,, treated at its resonant frequencles of the V_..SriDLIS harmonics with A the aid of an electromechanical unbalance vibration exciter Connected to an electric motor, till stabiliZ8tiDn Of the resonant frequencies, according to the invention, the value Of the electromotive force of the electric motor arinature bearing is Continuously measured in the course of the vibratory tratment once the e.m.f. value has ceased chant; ing, the vibra tion exciter is tuned to resonance in the natural fu- equency Of the,,vorkpiace that has been shifted as a result Of the vibratory treatment and multiply repeated vibratory excitation is carried out on each of the harmonics till reachinS a frequency at which the e.m.f. remains invariable.
The development mechanism Of the e.m.f. in the bearings of electric M0tDrS is based on the phenomenon Of tb6 6.M.f. induction in case of a nonsymmetrical magnetic flux in the ma=-netic system of a circuit consistin-. of a shsft, a bea-in,5 and an electric motor frame. The electric motor arrra-.u-re shaft runs in bearin..s, wh--,.rein a hydrodynamic oil film is formed, whose electrical resistance varies depending on the electric r,,o-VDr operating duty. ''ihen the bearing is electrically insul-sted from the electric motor frame an e.m.f. c3n be detected across the electrical terminals of -U'--a zao-wc)r frame and t-be bearir,,: race.
W The condition of i;he Iiyd--odynamic oil film depends z 1 51 on the reaction of the workpiece being treated, which is translated via the vibration exciter to the shaft of the electric motor armature, while the e.m.f. value is drastically increased in the resonant mode.
It is due to the e.m.f. of the bearin- that One can register the force Of vibratory affects uninterruptedly.
A signal informing on the e.m.f. value in the bearing is employed for CDnt201 of the vibratory treatment process.
Treatment Of WDrkpiece in the resonant mode of vibratory forces in the bearing makes it possible to take account Df a current change in the resonant frequency due to the kinetics of residual stresses.
Termination of the treatment procedure upon dis- continuation of the e.m.f. chan-es in the bearing -t,rDvides for high- accuracy re-istration of the inszant 1 c CJ of final stabilization of residual stresses in the workpiece being, treated.
Vibratory treatMellt is carried out in a resonant 20 mode at a stabilized vibwation rate at which energy ut in the workpiece and absorbed by it ensures maxi mally a considerable saving Of energy consumed due to a shorter lapse of time within which residual stres ses in the WDrkpiece a.-e reduced.
_RegiStratiDn Of the instant Of final st,---biliza'U!Dn of residual s-jresses in the workpiece and termination 0 L Of the treatment procedure make it possible to exclude the time of unproductive vibratory effects pest stabilizatiDn of residual stresses.
According to one of the embodiments Of the in- vention vibratory treatment is discontinued in the course of tuning of the vibration exciter. Such an embodiment of the invention makes it possible to use relatively simple equipment for carrying the method of the invention into effect.
According to 8 preferred en.ibDdi:aent of the invention vibratory treatment is cDnduct'jed continuously witbin the entire process of vibratory effects.
Such an em,'oodi.uant Of the inve.-ú.-GiDn en-bles one to completely. 3utoiiiate the process of vibratory treatment of wo-rkpieces.
The aforesaid object is acco:.-plished also due to the fact that in a device for vibratory treatment Of WDrkpieces, comprising an electrDmacbenical unbalance vibration exciter connected to a varieblespeed electric =otor, a voltso.e cnvever and a measuring instrument, accDrdin-. to the invention, prDvision is also maude- therein for an amplifier, an automatic electric =otD-r speed s-uabiliza-uiDn unit, and an electric i-D-Uor angular speed pickup, the race of one of t-he bearings of the electric:iD'Uor armature is electrically i. -,suln-ted from the electric motor frame, the input of the automatic electric motor speed stabilization unit is connected, through the electric motor angular speed pickup and a CDMMUt8tDrg to the -electric motor armature winding, whereas the output of the electric motor speed stabilization unit is connected to the converter input, and the measuring instrument is connected to the amplifier output, the amplifier input being connected to the electric motor frame and lu-D the race of the electric motor armature bearing.
In a prefer-red embodiment of the invention provision is made for a setter of intensity of the input voltage variazion of the automatic electric motor speed stabilization unit and for a computing unit, the input of the automatic speed stabilizatiDn unit being; Con nected, via the setter, to tha unit, which in turn is connected to the measuring instrument in order to print out data on the vibratory treatment process o.L" t-he workLiece involved, end tUD the amplifier output.
Such an embodiment of the present invention is efficient 'LDr complete automation of the vibratory Ureatment process of a workpiece.
Further objects and advantages of the present invention will become more apparent frDr. a =nsideration of the following detailed description of Some specific exemplary embDdiLie-..'Vs 'tv-, ereDf and the accompanying drawings, wherein:
FIG. 1 is a schematic view of a device, according to the invention; FIG 2 is an alternative embodiment of the auto- matic electric motor speed stabilization unit, according to the invention; FIG. 3 presents an electromechanical cberacteristic of the vibxation exciter, sccD=ding to the i,.,.v e r. t i c) n; FIG& 4 depicts a frequency-and-amplitude characteristic of the e.m.f. variation with due account of resonance on zte various 1.i..rmDnics, according to the invention; and FIG. 5 -e-,-as,nts an amplitude-frequency charac- texistic of the a.-n.f. and itis shiftin due to vibratory excitation.
The meubz)d for vibratory trea'u,-ient of workpieces, according to the CD,'SiSq-S in tbe following.
The wDr.cpiece bein-:.;. treated, viberein residual stresses j are present, is sub.jected to v-Lbr!3tDry excitation witb the aid of an electrc)mecbp-nical unbalance vibration exciter connected to an electric iLDtor, said vibratory excitation of the wDrtpiece being effected at its reson-.nnt frequencies on the various bar- monics. The -vlue D:E the electric motor armature bearin. is measured Continuously in the CDUXSe Of vibistory treatment process. A change in.the e.m.f. value results from a reduction of residual stresses in the workpiece due to vibratory treatment thereof At each Df the treatment stages On e should retune the vibratory excitation frequency On a preset harmonic so as to provide resonance at the wDrkpiece natural frequency that has been shifted as a result of vibratory treat..-ient, making use of a signal Of a change in the e.m.f. value. Once the e.m.f. value has ceased charigin6 on each of the harmonies, tbe vibration exciter is tuned in the frequency of an adjacent harGi...Inic. Vibratory excitation is repeated niany times in succession sta-.,,e-bv-sta-e until a C.) frequency is reached at which the value changes no lon,Ser.
The vibration exciter is 'Uun.a,"' in tb,:, frequency of an adjacent h3rmonic either et. th- interval between the stages of tube treatment a. different ber=D- nics Or CUZUDM8tiCC1ly in the COUl'SS Of '-'D,'tinUC)US vibration treatment Of the The device for carrying the riethod for vibratory treatment of into effect co,-,,b)rises an eleCtrDIU,3chanical unbalence vibretion, exciter 1 (FIG# 1) connected to a v,-riable-sp,ed electric MOtOr 21 C V01t2j. Convert a --epsurin,c" iristru- L er meat 49 an amplifier 5, 8 Unit 6 Of CL1t0M8tiC speed stabilizatiDn of the electric motor 2, a pickup 7 of angular speed of the electric motor 2, wherein 8 280e 9 Of One Of bearin.-s 10 Of its armature 11 is electrically insulated from a fteme 8 of the electric Motor 2, a setter 12 of intensity of the input voltate variation of the unit 6 of automatic Speed stabilizetion of the electric motor 2, and a computing unit 1.30 The input of the automatic speed stabilizetion unit 6 is connected, through the setter 12, to the computing unit 13, which in turn is Connected to the measuring instrument 4 in order to print out date on the workplace vibratory trectment process, and tD the DUtpUt. of the amplifier 5 and is also cDnnected,tbrDU6b the pickup 7 of anp-.ular speed of the electric mDzDx 2 and a commutator 15, to the winding of the armature 11 of the electric motor 2. while the output of the unit 6 is connected to the input of the converter 3. The measuring instrument 4 is connected to the output.
of the amplifier 5 whose input is connected, tbrough a terminal A, to the frame 8 of the electric motor 2 andg through a terminal B, to the race 9 of the bearin- 10 of the ermr--ture 11 of the electric motor 2. The direct-current electric motor 2 is -Dwered froia the converter 3 of electric voltage in the capacity of -Y,V;hich is used a Controlled rectifier adapted to rectify Cowmercial-frequency elternating- current voltage and a,.,ide-range control of the rectified voltage Ud of direct (pulsating) current. The cortrolled rectif ier is built around thyristors according to a full-wave centre-tap circuit. The tbyristors are powered from a power transformer, which effects deCDupling of the electric motor circuits frD-a power mains and steps mains voltage down to a level safe as for the operating conditions specified.
The pickup 7 is used for measu-rinz;i a current value of the angular speed n of the electric motor 2. Under constant magnetic flux of the electric motor 2 its speed is measured with the aid of a tachometric bridge rall-ber than by means of a t8CbDc-,enera'.-Dr. An electromotive force T is induced across the terminals and D of the winding of the arTRture 11 of the electric motor 2, said force T being determined from the relationship:
F = b. F. Q where b - electric motor constant; F - m-,o.netic flux; an-uler rot-azion speed of t-he electric motor 2.
The input of the Oickup 7 is connected to the terminals C and D z)f the electric motor 2. Voltuage picked off the LL-upuu of the Pi4UP 7, is proportiOn81 tUD the V_1U6 of T and hence zo the speed Q of the electric motor 2 under steady-state cDriditions.
Application of the pickup 7 for raeasurinc--l the rotation speed of the electric motor 2 instead of a conventionally employed tacbDgenerator simplifies the construction of the electromechanical exciter and makes its operation more reliable.
The unit 6 of automatic stabilization of tibe speed of the electric ElDtDr 2 Maintains 8 preset rotation speed of the electric wo.'U-Dz 2 in cases of such ext- rinsic distuxbint factors as fluctuation of alternatin,..-cu.r.renju- mains vDlll-age, cbanr-es in the condition of the lubricant in the electric motor 2, change in mechanical and electrical losses in the electric motor 2. Application of a negg.ive feedback makes it possible -.D prDvid.e linear cbs-r-,-c.;u-ariszics of the converter which, ir. tur, extends the ran-e of the speed control of electric izD-GDr The unit o is in --'act a prDpDr-L;iDnal-pulse-integral CDnt4rDller 2nd a discrete speed setting subunit (FIG. 2).
The erntXDII---r is besed on an Dperational ampli flex, which incorporates in its feedback circuit a resistor R 1 and a cepecitDr Cl The controller feedback is e-'fe,3.,..ed b.. resistors R7 of the speed settin, eircui,s and b, resistor 7' Q, 4 in the speed feedback ci--cui: of the electric motor 2. The speed setting subunit is in effect a variable resistor R 5 connectable to a voltage U S of a source of stabilized direct current through 8 Switch Si. The slider of the resistor R 5 is connected to the resistor R2.
Tbe setter 12 of intensity of'the input voltage variation of the unit 6 is connected to the resistor R through a switch S 2 mechanically interlocked with the switch S 1 so that when the switch S2 is closed the switcb S 1 is open and, vice versa,,iitb the switch S 1 closed the switch S. is open.
The setter 12 of intensity of the input voltage variation of the unit 6 is adapted for Converting stepwise variation of the voltage from the output of the computing unit j into a voltage vexying .0 linearly with time and set at the unit 6. The level of the output voltage from the computing unit 1--0 after having been reproduced by the int-e- sity setter 12 reaches the level of the inpu-., voltage of the unit 6. Linear variation of the Voltage setter 12 from the zero to the maximum value en-Ibles the electric motor 2 to be speeded up wit-h a constant acceleration, tbereby realizing tibe ran-e of vibratiDn fre-luencies defined by the rotation speed of the electric motor 2.
Application of the setter 12 facilitates Con- duction of vibrs-uory treet.ment at the nat-ural 'Lrequencies of the.. iorkpieces 14 bein treated and enables automation of tube vibration treatment, process.
(1 The CD=PUting unit 13 makes it possible to automate the process of vibratory treatment of the workpiece 14 and provides for flexible prDgXaaaed control over the technological process of vibratory treatment.
The unit 13 incorporates all principal routine elements inherent in any computing system, i.e., an aritbmetiC-ID,iC81 d6ViCeSq a memory device, an input output device, and a contrDl device.
The input-Dutput- device establishes communication between the unit 13 and the setter 12 and, via the amplifier 5, with the terminal A on the frame 8 of the electric motor 2 snd with the terminal B of the bearing 1.3 electrically insulated from the frame 8 of the electric motor 2.
The memoxy device is used for storing of programs and recording of information on the value of the bea ring e.a.f., arrives from the bearing 10 electri cally insulated 'L-.rom the fraze 8 of the electric 2, thXDUIA the ampliSfier 5 and is applied to the unit 13, as well as on the value of she Du-Upu-, voltage of the setter 12.
The control unit is adap-uted for deCDdin,z- the cDmmands recorded in a program and si-juals for the computin6 unit to function.
For drawin- up documents contcerninjg with the .1 v technological of vibratory tre.tment of the workpiece 14 the resonant frequencies of vibratory excitation are printed out and taken down by a recorder (oiaitted in the Drawing) connected to the measuring instrument 4. A direct-current electric motor powered:from the voltage converter 3 is used as the.electric motor 2. The output of the Converter 3 is connected to the winding of the armature 11 of the electric motor 2 through the terminals C and D of t;e commutator 15. The electric motor 2 has sepgr?te excitation.
'1,Vh e n substantia-Ging the ope-rating conditiDns of the electric mozor 2 and ij-,,skin,- an analysis into the conditions for its stable operat-ion in cDzLbination with the vibration exciter 1, use is made of a relatiDnsbip between the speed C2 of the electric motor 2 and the torque L. on the shaft thereof. The mechanical characteristic of the electric iaDtor 2 varies linearly (FIG. 3) with respect tD the v-I-ue of QD1 iseof a no-1Ded angular speed of the electric jiDtDr 2. Under steady-state conditions with n = C- 1 the value of the torque V1 on the shaft of the electric Motor 2 equals the value of the antitorque moraent lb.' C that is.
C Arl, 1 =Mio The value of the antitorque P-Dment L.C derDe nds 1 1 on the amount of 2 vib2atory force iesultiriG. from rotation of the shaft of the vibr3uic)n exciter 1 secured on the wDrkt,i-.ce 14.
When the frequency of vibratory excitation equals one of the nmtural frequencies of the workpiec6 14 being treated, resonance ststs in, and the vibratory force MC acquires its maxiiaua value. When a deviation froa resonance occurs the value of the vibratory force Mc dec--eases and hence the antitorque moment, durin6 the motor shaft rotation, gi:ts lower than the value of 1, while the angular speed of the electric motor 2 rises up to the value of A decrease in the natural frequency of the work- piece bein- treated due to vibratory treatment results in a reduction of the e.m.f. value. Prior to eDm:nensinc, vibratory treatment of the workpiece 14 one should determine i-Lu-s resonant freThen the speed values of tbe electric quencies. U motor 2 corresDi)ndin. to said resonant frequencies, mre entered into the memory of the CDMPUtin- unit 1 13.
For carrying Duz vibratory treatment the vibxa- tiDn exciter is to be fixed in place on the work- t)iece 14 bein- treated with the aid of the clamps 16.
Then the rots-Gion speed of the electric motor 2 is chanSed so as to attain a mechanical resonance, i.e., a vibratory effect is exerted in such a man- nex that the vibratory excitation frequency (as set by rotation speed of the electric motor 2) should get equal to one of the resonant frequency of the workpiece 14.
1 Vibratory treatment is effected at a constant rate of vibratory effects. To this effect use is made of the speed setter 12. The value voltage variation across the pickup 7 is subtracted in the auto- matic speed stabilizazion unit 6 from the value of the Voltage across the setter 12. whereby a negative feedback with respect to the.SPeed of the electric motor 2 is ensured.
FIG. 4 shows a;..raphic representation of the nature of the process of vibratory effects. The electric MOtDr 2 is speeded up with constant accele.ration so that the anjular speed Q of the electric Motor 2 rises up to its rr-axi:num value n Max As soon as the vibratory e--,,citation frequency falls in coincidence with one of the resonant frequencies of the workpiece 14 the e.ia.f. of the bearing 10 reaches its maximum value a' max, The initial vibratory excitation is carried DUt either at the lowest ox at the bimibes'u- natural frequency of the WDrkpiece 14 within the preselec+.,-:d frequency range.
In the course of vibratDry excitation micrDplastle deformations are lible to occur in the material of the wDrkpiece 14, -i;izb the result that the internal residual stresses therein are reduced and get stabilized during further treptment. Such chan-es in the residual stresses in the workpiece 14 resulting frora vibratory excitation lead to a change in the resonant frequency of the wDrkpiece 14.
FIG. 5 illustrates the process of vibratory excitation at one of the resonant frequencies of the wDrkpiece 14. With vibratory excitation carried out at the resonant frequency Q 1 (indicated i,.,itb a Solid line in the graphic ch-art) the e.m.f. of the bearing, 10 reaches its maximum value -awxe As a result of such vibratory excitation at said frequency microplastic deformations in the material of the workpiece 14 occur, internal residual stresses are reduced, the e.m.f. value of the bearin.. 10 drops, and the resonant fre- U quency of the WDrkpiece 14 is shifted towards the lower-frequency region. The value of nn is cberseteristic of a resonant frequence driLt as a result of partial reduction of the internal residual stresses In the wDrkiece bein.5 treated. The e.m.f. of the bearinE 10 acquires its iiaximum value this time at a frequency of vibratz;ry excitation that has been shifted as -- result of vibratorytre2tment (indicated with a dotted line in the,.rapbic chprt). In the case of incDincidence of the vibratory excitation frequency -;,,ith one of t_e reson-a-nt frequencies of the work piece 14 the of the bearinx 10 has a lov,,er value, 1 EE lain The process Of vibratDr.V tZeatMent is effected in an alltOM.3tiC Continuous ntode. Upon initial vibratory loading of the workpiece 14 On a preset beritonic, there is carried out, as a result Of operation of the unit 6, aniutDmEtic tuning to resonance till stabilization Of the e.m.f. value Of the bearinS 10. Then the CDMPUting unit 13 seends a command to change to an adjacent bariaonic featured by another resonant freauency. Then tunin,,. to resonance is also performed at this new sta,, e till stabiliZatiDn Of the e.M.f. Value Of the bearing 10. Vibratory treatment is discontinued as soon as the e.m.f. value Of the bearing 10 remains cDnstan-r after changing over to an adjacent harmonice A simplified version of the method proposed herein can be carried into effect without the use of t.:-e setter 12 and the computin- unit 13.
0 In such a case vibratory treati;enlu- of the work- piece 14 is interrupted and the vibration exciter 1 is retuied with the aid of the unit 6 in a descrete mode.
Next the e.m.f. Value Of the bearing 10 is read Off the iaessurinj instrument 4 and vibratory excitation continues at P- -Aver, frequency till stabilization of the e.m.f. value, i.e., when the mini:num value of the e.m.f. of the bearing 107 as reed by the instrument 4 does not change, vibratory excitation is discontinued, wbe.reupDn retuning in the frequency that has been shifted as a result of partial relieving of internal stresses in the wDrke..iece 14 is carried out and vibratory effects ire repeated. Vibratory excitation on a given harmonic is discontinued whenever the e.a.f. value does not eban;e after a next retuning of the vibration exciter 1 to resonance and remains at its maxiraum. 'This vex-,. instant is in fact the point of final stabilizatiDn of internal stresses in the workpiece 14 on e eiven bermonic. As a result, microplastic deformations in the matexial of the workpiece 14 cease, as well as virDrous absorption of the energy of vibrations by the.,orkpiece 14. ThereuDn vibratory excitation of the -.'. Drkpi---ce 14 at another resonant frequency is carried out followed b.., similpr vibratory excitation procedures st other resonent fr--,--,uencies of the viorkpi-ce 14.
The pro-ldss of treatment is ter.minated whenever no reduction of the e.=,.f. value occurs as a result of vibratory emcitation at other resonent frequencies z)f te workpicce 14, -xhich is re,Istered cl P,:,.ainst the instrument 4.
za,
Claims (6)
1. A xetbod for vibratory treatment of workconsisting in multip;y repeated vibratory excitation of the workpie,ce being treated at Its resonant frequencies of various baimonies by an electromechanical unbalance vibration exciter connected to an electric motor, till stabilization of the resonant frequencies; the value of the e.nL.f. of the electric motor armature bearing is measured cDntinuousy, in the course of the vibratory treatment, once the e.m.f. value has ceased varying, the vibration exciter is ttined to resonance in the natural frequency of the iDrkpiece that has been shifted due to the vibratory treet:.,,ent, and multiply repeated excitation is carried out on each of the harmonics till reaching a frequency at which the e.m.f. changes no longer.
2. A method as claimed in Clai.TI 1, wherein vibratory treatment is discontinued in the course of tuninS of the vibration exciter.
3 A me-u'-bc)d as clairued in Clai-1 1, wherein vibratory treatment is carried out continuously during the entire,)rDeess of vibratory effects.
A device for carryin6 into effect a method for vibratory tre8tMent of workpieces as claimed in Clai-r. 1, comprisinr an electromechanical unbalance L) vibration exciter connected to a variable-speed electric motor, a voltage converter, a measuring instrument, an amplifier, an automatic electric motor speed stabilization unit, and an electric motor angular speed pickupg the race of one of the bearings of the electric motor armature is electrically insulated from the electric motor frame. the input of the automatic electric motor speed stabilization unit is connected. through the electric motor angular speed pickup, and a commutator. to the electric motor armature winding, whereas the output of the automatic electric motor speed stabilization unit is connected to the converter input, and the measuring instrument is connected to the amplifier output, the amplifier input being connected to the electric motor frame and to the race of the electric motor armature bearing.
5. A device as claimed in Claim 4. wherein provision is made for a setter of intensity of the input voltage variation of the automatic electric motor spee& stabilization unit and for a computing unit, the input of the automatic speed stabilization unit being connected.. through the setter, to the computing unit, which is turn is connected to the measuring instrument in order to print out data on the vibratiDrv treatment process of the V,W,Drkjiece involved, and to the amplif ier output
6. A method as hereinbefore substantially as disclosed in the present description with reference to, and as shown in the accDmpanyitig drawints.
A device as hereinbefore claimed substantially as disclosed in the present description witb reference to, and as shown in the accompanying drawings.
i i Published 1991 at The Patent Office. State House. 66171 High Holborn, London WC I R 47P. Further copies may be obtained from Sales Branch, Unit 6, Nine Mile Point, Cwmfelinfach. Cross Keys, New-pom NPI 7HZ. Printed by Multiplex techniques ltd. St Mary Cray. Rent.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8928301A GB2239108A (en) | 1989-12-14 | 1989-12-14 | Vibrating workpieces |
| DE19893942079 DE3942079A1 (en) | 1989-12-14 | 1989-12-20 | METHOD FOR VIBRATING MACHINING PARTS AND DEVICE FOR IMPLEMENTING THE SAME |
| FR8917138A FR2656436A1 (en) | 1989-12-14 | 1989-12-22 | PROCESS FOR VIBRATION PROCESSING OF PARTS AND DEVICE FOR IMPLEMENTING SAID METHOD. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8928301A GB2239108A (en) | 1989-12-14 | 1989-12-14 | Vibrating workpieces |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8928301D0 GB8928301D0 (en) | 1990-02-21 |
| GB2239108A true GB2239108A (en) | 1991-06-19 |
Family
ID=10667958
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8928301A Withdrawn GB2239108A (en) | 1989-12-14 | 1989-12-14 | Vibrating workpieces |
Country Status (3)
| Country | Link |
|---|---|
| DE (1) | DE3942079A1 (en) |
| FR (1) | FR2656436A1 (en) |
| GB (1) | GB2239108A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105344577A (en) * | 2015-12-04 | 2016-02-24 | 张劲南 | Eccentric shaft barrel type vibration exciter with adjustable force and frequency |
| CN105811673A (en) * | 2016-04-05 | 2016-07-27 | 宁波德昌电机制造有限公司 | Automatic welding machine |
| CN105904130A (en) * | 2016-04-05 | 2016-08-31 | 宁波德昌电机制造有限公司 | Motor commutator continuous welding device |
| PL238058B1 (en) * | 2018-09-25 | 2021-07-05 | Inst Spawalnictwa | Hybrid vibration device, in particular for dimensional stabilization of metal products |
| PL238990B1 (en) * | 2018-09-25 | 2021-10-25 | Inst Spawalnictwa | Vibration device, in particular for dimensional stabilization of metal products |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999021665A1 (en) * | 1997-10-27 | 1999-05-06 | Alexandr Petrovich Yarlykov | Method for improving the operation, preparing the exploitation and maintaining the operation conditions of rolling cylinders |
| US6916387B2 (en) * | 2002-05-06 | 2005-07-12 | Howmet Corporation | Weld repair of superalloy castings |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU673997A1 (en) * | 1977-03-05 | 1979-07-15 | Ордена Ленина И Ордена Трудового Красного Знамени Институт Электросварки Им.Е.О.Патона Ан Украинской Сср | Device for relieving residual welding voltages |
| SU897441A1 (en) * | 1979-12-12 | 1982-01-15 | Всесоюзный Проектно-Конструкторский Институт Сварочного Производства | Method of decreasing residual stress and residual deformations in welded constructions |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3622404A (en) * | 1969-02-19 | 1971-11-23 | Leonard E Thompson | Method and apparatus for stress relieving a workpiece by vibration |
| SU798185A1 (en) * | 1979-04-09 | 1981-01-23 | Экспериментальный Научно-Исследовательскийинститут Металлорежущих Станковвильнюсский Филиал | Method and device for control of structure vibrotreatment |
-
1989
- 1989-12-14 GB GB8928301A patent/GB2239108A/en not_active Withdrawn
- 1989-12-20 DE DE19893942079 patent/DE3942079A1/en not_active Withdrawn
- 1989-12-22 FR FR8917138A patent/FR2656436A1/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU673997A1 (en) * | 1977-03-05 | 1979-07-15 | Ордена Ленина И Ордена Трудового Красного Знамени Институт Электросварки Им.Е.О.Патона Ан Украинской Сср | Device for relieving residual welding voltages |
| SU897441A1 (en) * | 1979-12-12 | 1982-01-15 | Всесоюзный Проектно-Конструкторский Институт Сварочного Производства | Method of decreasing residual stress and residual deformations in welded constructions |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105344577A (en) * | 2015-12-04 | 2016-02-24 | 张劲南 | Eccentric shaft barrel type vibration exciter with adjustable force and frequency |
| CN105811673A (en) * | 2016-04-05 | 2016-07-27 | 宁波德昌电机制造有限公司 | Automatic welding machine |
| CN105904130A (en) * | 2016-04-05 | 2016-08-31 | 宁波德昌电机制造有限公司 | Motor commutator continuous welding device |
| CN105904130B (en) * | 2016-04-05 | 2017-09-19 | 宁波德昌电机制造有限公司 | A kind of engine commutator continuous welding device |
| CN105811673B (en) * | 2016-04-05 | 2018-04-27 | 宁波德昌电机制造有限公司 | A kind of automatic welding machine |
| PL238058B1 (en) * | 2018-09-25 | 2021-07-05 | Inst Spawalnictwa | Hybrid vibration device, in particular for dimensional stabilization of metal products |
| PL238990B1 (en) * | 2018-09-25 | 2021-10-25 | Inst Spawalnictwa | Vibration device, in particular for dimensional stabilization of metal products |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3942079A1 (en) | 1991-06-27 |
| FR2656436A1 (en) | 1991-06-28 |
| GB8928301D0 (en) | 1990-02-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |