CA1180043A - Multipolar stepping motor with intermediate stator rings - Google Patents
Multipolar stepping motor with intermediate stator ringsInfo
- Publication number
- CA1180043A CA1180043A CA000375904A CA375904A CA1180043A CA 1180043 A CA1180043 A CA 1180043A CA 000375904 A CA000375904 A CA 000375904A CA 375904 A CA375904 A CA 375904A CA 1180043 A CA1180043 A CA 1180043A
- Authority
- CA
- Canada
- Prior art keywords
- rotor
- teeth
- stator
- coil
- polar
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K37/00—Motors with rotor rotating step by step and without interrupter or commutator driven by the rotor, e.g. stepping motors
- H02K37/10—Motors with rotor rotating step by step and without interrupter or commutator driven by the rotor, e.g. stepping motors of permanent magnet type
- H02K37/12—Motors with rotor rotating step by step and without interrupter or commutator driven by the rotor, e.g. stepping motors of permanent magnet type with stationary armatures and rotating magnets
- H02K37/14—Motors with rotor rotating step by step and without interrupter or commutator driven by the rotor, e.g. stepping motors of permanent magnet type with stationary armatures and rotating magnets with magnets rotating within the armatures
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K1/00—Details of the magnetic circuit
- H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
- H02K1/12—Stationary parts of the magnetic circuit
- H02K1/14—Stator cores with salient poles
- H02K1/145—Stator cores with salient poles having an annular coil, e.g. of the claw-pole type
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
- H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
- H02K21/14—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures
- H02K21/145—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures having an annular armature coil
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K2201/00—Specific aspects not provided for in the other groups of this subclass relating to the magnetic circuits
- H02K2201/12—Transversal flux machines
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Iron Core Of Rotating Electric Machines (AREA)
- Permanent Magnet Type Synchronous Machine (AREA)
- Windings For Motors And Generators (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
The step-by-step motor is provided with a stator having an energizing coil for producing a magnetomotive force, and a rotor surrounded by the stator and having an axis about which it is rotatable. This rotor comprises along its circumferential periphery a succession of alternate magnetic dipoles to which is applied the magnetomotive force from the coil. The axis of the rotor passes through a bearing positionally fixed with respect to the stator. The stator of the step-by-step motor includes an inner cylindrical wall adapted for dividing the magnetomotive force of the coil applied to the rotor dipoles and comprising two end rings having polar teeth equal in number to the magnetic dipoles of the rotor, and at least an intermediate ring disposed between the two end rings and made of ferromagnetic material. This intermediate ring is secured to an inner wall of the coil and comprises two annular rows of polar teeth, the teeth of each row being angularly offset between the teeth in the other row. The number of teeth in each of these rows is equal to the number of the teeth of the end rings and to the number of the magnetic dipoles of the rotor.
The step-by-step motor is provided with a stator having an energizing coil for producing a magnetomotive force, and a rotor surrounded by the stator and having an axis about which it is rotatable. This rotor comprises along its circumferential periphery a succession of alternate magnetic dipoles to which is applied the magnetomotive force from the coil. The axis of the rotor passes through a bearing positionally fixed with respect to the stator. The stator of the step-by-step motor includes an inner cylindrical wall adapted for dividing the magnetomotive force of the coil applied to the rotor dipoles and comprising two end rings having polar teeth equal in number to the magnetic dipoles of the rotor, and at least an intermediate ring disposed between the two end rings and made of ferromagnetic material. This intermediate ring is secured to an inner wall of the coil and comprises two annular rows of polar teeth, the teeth of each row being angularly offset between the teeth in the other row. The number of teeth in each of these rows is equal to the number of the teeth of the end rings and to the number of the magnetic dipoles of the rotor.
Description
~ ~L E3 IJ ~ ~ 3 . ~
The prs~ent invent:lon r~lata~ to ~ ~tep b~ tep motor comprl~ine a multlpolar rotor9 a ~tator a~ociatad with the rotor and mean~ for producin~" ~or each pha~3a9 a magnetomo~ive ~oroo .
~ o~m motor3 of -thi~ type gen~rall;sr comprl~, coaxially a~sociated with the ro-tor, an annular ~tator hou~lng contalning the ~n~rgizing coil, ~or cach pha~o, and compri~ing 0, plurality o~ pol~r teeth or tongue8 qrhich are possibly imbricat0d snd adaptod to cooperate~ magn~tl~
10 cally Nith th~ rotorO
Tha number o~ ~tep~ that may be made by the rotor o~
such ~ motor i~ the course OI ~ complete revolution being a functio~ o~ the rlumber o~ polar teeth oX the 3tator, therfl aro n~nerouo applicationo, particularly in the domain of ~rvo-control and automatio devices where, to obtain the great~t po~ible preci~ion in the po~itioning o~ certain ~ervo-controlled member~ (measuring ~y~tem~, ~
printersD eto.), the greate~t po~ible angular reaolution, i.e. motor~ whLch ean make ~ largo n~nbsr of atep~ per re~olution o~ the rotor~ mu~t be available~
~ o obtaLn th:L~ h~h re~olution, oonvvn-tionnl prao-tlc~ ¢on~:L~t~ in inGrea~ing a~ much a~ po~.~lble the number o~ polflr ~e~th o~ th~ ~tator and oorr~lati~ly~ o~ cour~
th~ numb~r o~ rotor dipol~.
Howaver~ ~or a given motor o~ ~hloh tho eeomatric polar o-tructur~ ha~ bver~ adQpted optimall~ ~ith th~ charac-teristlc~ o~ the magnetomotive ~ouroe, it i~ observed that ,.,.~ j . ,~
~ 'i?~
~ ' th~ operation consl~tlng ln increa~ing the number o~
~tator pol0s oan only be carricd out to the d~trim~nt o~
th~ motiv~ power a~ailable on the rotor, l~e~ wlth a~
appraoiablo decrea~e oi the motor torqu~ e~en though it ~ought~ within the tolerable limlt~ o~ heat~ng ~d o-~ dema~
gnetization o~ tho rotor, to comp~n~a-te thi~ lo~ o~ motlv~
power by an increace in the eleotrical energizing power~
In ~aot9 the incraa~e in the number o~ ~tep~9 and con~aqu~ntly the decrea~3 o~ the angular value o~ each o~
the~e ~tep~, nece~arily brings about a decrea~ o~ the - wldth oP aach ~tator polar toothg a~ ~ell a~ a reduct~on in the ~pace ~eparatine t~o con~eoutivs teeth~ Thu~ the polar t~eth being o~ eupposedly unchanged thic~nees and height 9 their mutually oppo~ita lateral edge~ con~equently remaining idantlcal, tha rsluctanc0 o~ the stator cLrcuit docrea~es in proportion to the ~paca between toeth to th~
point that th~ increa~e in the leakage ~lu~ re~Lting there~rom bring~ about magnetio ~atur~tion o~ th~ teeth o~
~hioh the ~eotion ha~ bcen r~dueod.
Thia phenomenon o~ ~aturatlon oi the etator polar teeth there~or~ constitute~ a limit to tha increa~e in the moti~e power of a given motor oP ~hlch it i~ de~ired to i~orea~e tha number o~ ~tsp~.
When, de~p:Lte ~hie Limlk~ ib i~ do~irod that the ~iLabl~ motiv~ power be gr~ster th~n t~t ~hich it allow~
to be attairl~d ~or a determined numb~r o~ ~tep~, it i~ then neoe~ary~ in known mQnner~ in tho ~lr~t place, to raduce the haiBh~ o~ the ~tator polar t~eth o~ the givan motor in ordar to po~tpone the appearance o~ the detrim~nt~l phano~
~0 menon o~ ~a-turntlon then, .tn the ~econd plao0y thi~
.0 2 reduction in polar height allowing the decrease in -the axial height of -the mo-tor, to compensate for the loss of available motive power by coupling on the same shaft as many identic,al motors as are necessary for obtaining the desired torque.
This known method obviously presents the drawback of high production costs since the number of the technologi-cal elements constituting the step-by-step motor unit procuring the desired motive power must be multiplled by as many times as it is desired for example to double the number of s-teps.
It is precisel~ an object of the present invantion to eliminate this drawback by providing a technological.ly simple and economical means for maintaining at its original value the available motive power of a step-by-step motor with multipolar magnetized rotor whose resolution it is desired to increase by multiplication of the number of polar steps.
More particularly, according to the present inven-tion, there is provided a step-by-step motor comprising:
a stator having an energizing coil for producing a magnetomotive force;
a rotor surrounded by the stator and having an axis about whieh the rotor is rotatable, this ro-tor havincJ a cl.rcum~erentlal periphery and a succession oE altcrnate ma~netic dipoles dispoc;ed a].oncJ its circumferential periphery and ko wh:Lch the macJne-tomotive force o the coil ls applied;
a bearin~ which :Is pos:ltlonally Elxed wlth rcspect ko -the stator ancd through wh;i.ch the c,lxls o:E the rotor passes;
wherein the stator includes an lnner cyllnd:r:lcal wall adapted Eor d:lviding the ma~netomotive force of l,he coll appli.ed -to the magnetic dlpoles oE the rotor and eomprislny two end rings having polar teeth in a number equal to that oE
the magnetic dipoles of the rotor, and at least an i.nter-~ "
;~ - 3 -?~L~3 rnedia-te ring disposed between the two end rings and made of ferromagnetic material, this intermediate ring being secured to an inner wall of the coil and comprising two annular rows of polar -teeth, the teeth o~ each row beinc; angularly of~set between the teeth in the other row; the number oE the -teeth of each row being e~ual to the number of the teeth of the end rings and to the number of the dipoles of the rotor.
The invention will be more readily understood up on reading of -the foLlowing non-restrictive description given L0 for the purpose of exemplification only with reference to the accompanying drawings t in which:
- Fig. 1 shows the diametrical section through a step-by-step motor which, according to the known technique, comprises a double stator.
- Figs. 2 and 3 show how, on a developed diagram of stator multipolar system, the reluctance and section of the polar teeth of a known motor evolve when the angular value of a step is reduced by half.
- Fig. ~, which is disposed on the same shee-t oE
drawings as Figure 1, shows, par-tly in perspective, a pre-ferred embodiment o -the structure of the stator multipolar .system associated with the rotor of a step-by-step motor :Lmproved ac~cordi.rlcJ to the :Lnvention.
Re~errincJ now to the drawings, the step-by-step motor o~ Fig. 1, whose struct~lre :i.s we:Ll known, comprises a cylindxiccll xo~ox 1 whose sha~t 2 to which it is connected by a r:Lm 3, pivots in the bearincJ 4 fast with a support 5.
The rotor, which is ~or example rnade o~ hard ~err.Lte, is magnetized so as to presen-t, along -the peripheral ~eneratrices, a succession oE alternat~-3 magnetic dipoles. The rotor 1 is surrounded by a first stator housing 6, generally annular in ~orm, which is fast with the support 5 and which . ~ .
contains an energizing coil 7 with multiple windings to allow supply from a generally polyphased electrical source.
q~
The magneti¢ circuit, con~titutted by the ~tator houslng 6" is interrupted on it~ inner cylindrlcal ~all ~o as to preaent a multlpol~r ~ystem 60 con~t~tuted by a plurality oî teeth o~ which the alte~nate, generally imbricated arrangement determine~ along the generatrice~
air ~pace~ ~rhioh Qra the seat of a leakage ~lwc produced by ths ma~;netomotivs force o~ the coll and peripherallyr oriented by the direction oi~ the energizln~ current9 ~o ~ to eoop0rat0 ~ith the P~ oP the magnetized dipole~
o~ the rotor 11, Thi~ known arrEmgement, which i~ illuetratod in Fig~ O
The prs~ent invent:lon r~lata~ to ~ ~tep b~ tep motor comprl~ine a multlpolar rotor9 a ~tator a~ociatad with the rotor and mean~ for producin~" ~or each pha~3a9 a magnetomo~ive ~oroo .
~ o~m motor3 of -thi~ type gen~rall;sr comprl~, coaxially a~sociated with the ro-tor, an annular ~tator hou~lng contalning the ~n~rgizing coil, ~or cach pha~o, and compri~ing 0, plurality o~ pol~r teeth or tongue8 qrhich are possibly imbricat0d snd adaptod to cooperate~ magn~tl~
10 cally Nith th~ rotorO
Tha number o~ ~tep~ that may be made by the rotor o~
such ~ motor i~ the course OI ~ complete revolution being a functio~ o~ the rlumber o~ polar teeth oX the 3tator, therfl aro n~nerouo applicationo, particularly in the domain of ~rvo-control and automatio devices where, to obtain the great~t po~ible preci~ion in the po~itioning o~ certain ~ervo-controlled member~ (measuring ~y~tem~, ~
printersD eto.), the greate~t po~ible angular reaolution, i.e. motor~ whLch ean make ~ largo n~nbsr of atep~ per re~olution o~ the rotor~ mu~t be available~
~ o obtaLn th:L~ h~h re~olution, oonvvn-tionnl prao-tlc~ ¢on~:L~t~ in inGrea~ing a~ much a~ po~.~lble the number o~ polflr ~e~th o~ th~ ~tator and oorr~lati~ly~ o~ cour~
th~ numb~r o~ rotor dipol~.
Howaver~ ~or a given motor o~ ~hloh tho eeomatric polar o-tructur~ ha~ bver~ adQpted optimall~ ~ith th~ charac-teristlc~ o~ the magnetomotive ~ouroe, it i~ observed that ,.,.~ j . ,~
~ 'i?~
~ ' th~ operation consl~tlng ln increa~ing the number o~
~tator pol0s oan only be carricd out to the d~trim~nt o~
th~ motiv~ power a~ailable on the rotor, l~e~ wlth a~
appraoiablo decrea~e oi the motor torqu~ e~en though it ~ought~ within the tolerable limlt~ o~ heat~ng ~d o-~ dema~
gnetization o~ tho rotor, to comp~n~a-te thi~ lo~ o~ motlv~
power by an increace in the eleotrical energizing power~
In ~aot9 the incraa~e in the number o~ ~tep~9 and con~aqu~ntly the decrea~3 o~ the angular value o~ each o~
the~e ~tep~, nece~arily brings about a decrea~ o~ the - wldth oP aach ~tator polar toothg a~ ~ell a~ a reduct~on in the ~pace ~eparatine t~o con~eoutivs teeth~ Thu~ the polar t~eth being o~ eupposedly unchanged thic~nees and height 9 their mutually oppo~ita lateral edge~ con~equently remaining idantlcal, tha rsluctanc0 o~ the stator cLrcuit docrea~es in proportion to the ~paca between toeth to th~
point that th~ increa~e in the leakage ~lu~ re~Lting there~rom bring~ about magnetio ~atur~tion o~ th~ teeth o~
~hioh the ~eotion ha~ bcen r~dueod.
Thia phenomenon o~ ~aturatlon oi the etator polar teeth there~or~ constitute~ a limit to tha increa~e in the moti~e power of a given motor oP ~hlch it i~ de~ired to i~orea~e tha number o~ ~tsp~.
When, de~p:Lte ~hie Limlk~ ib i~ do~irod that the ~iLabl~ motiv~ power be gr~ster th~n t~t ~hich it allow~
to be attairl~d ~or a determined numb~r o~ ~tep~, it i~ then neoe~ary~ in known mQnner~ in tho ~lr~t place, to raduce the haiBh~ o~ the ~tator polar t~eth o~ the givan motor in ordar to po~tpone the appearance o~ the detrim~nt~l phano~
~0 menon o~ ~a-turntlon then, .tn the ~econd plao0y thi~
.0 2 reduction in polar height allowing the decrease in -the axial height of -the mo-tor, to compensate for the loss of available motive power by coupling on the same shaft as many identic,al motors as are necessary for obtaining the desired torque.
This known method obviously presents the drawback of high production costs since the number of the technologi-cal elements constituting the step-by-step motor unit procuring the desired motive power must be multiplled by as many times as it is desired for example to double the number of s-teps.
It is precisel~ an object of the present invantion to eliminate this drawback by providing a technological.ly simple and economical means for maintaining at its original value the available motive power of a step-by-step motor with multipolar magnetized rotor whose resolution it is desired to increase by multiplication of the number of polar steps.
More particularly, according to the present inven-tion, there is provided a step-by-step motor comprising:
a stator having an energizing coil for producing a magnetomotive force;
a rotor surrounded by the stator and having an axis about whieh the rotor is rotatable, this ro-tor havincJ a cl.rcum~erentlal periphery and a succession oE altcrnate ma~netic dipoles dispoc;ed a].oncJ its circumferential periphery and ko wh:Lch the macJne-tomotive force o the coil ls applied;
a bearin~ which :Is pos:ltlonally Elxed wlth rcspect ko -the stator ancd through wh;i.ch the c,lxls o:E the rotor passes;
wherein the stator includes an lnner cyllnd:r:lcal wall adapted Eor d:lviding the ma~netomotive force of l,he coll appli.ed -to the magnetic dlpoles oE the rotor and eomprislny two end rings having polar teeth in a number equal to that oE
the magnetic dipoles of the rotor, and at least an i.nter-~ "
;~ - 3 -?~L~3 rnedia-te ring disposed between the two end rings and made of ferromagnetic material, this intermediate ring being secured to an inner wall of the coil and comprising two annular rows of polar -teeth, the teeth o~ each row beinc; angularly of~set between the teeth in the other row; the number oE the -teeth of each row being e~ual to the number of the teeth of the end rings and to the number of the dipoles of the rotor.
The invention will be more readily understood up on reading of -the foLlowing non-restrictive description given L0 for the purpose of exemplification only with reference to the accompanying drawings t in which:
- Fig. 1 shows the diametrical section through a step-by-step motor which, according to the known technique, comprises a double stator.
- Figs. 2 and 3 show how, on a developed diagram of stator multipolar system, the reluctance and section of the polar teeth of a known motor evolve when the angular value of a step is reduced by half.
- Fig. ~, which is disposed on the same shee-t oE
drawings as Figure 1, shows, par-tly in perspective, a pre-ferred embodiment o -the structure of the stator multipolar .system associated with the rotor of a step-by-step motor :Lmproved ac~cordi.rlcJ to the :Lnvention.
Re~errincJ now to the drawings, the step-by-step motor o~ Fig. 1, whose struct~lre :i.s we:Ll known, comprises a cylindxiccll xo~ox 1 whose sha~t 2 to which it is connected by a r:Lm 3, pivots in the bearincJ 4 fast with a support 5.
The rotor, which is ~or example rnade o~ hard ~err.Lte, is magnetized so as to presen-t, along -the peripheral ~eneratrices, a succession oE alternat~-3 magnetic dipoles. The rotor 1 is surrounded by a first stator housing 6, generally annular in ~orm, which is fast with the support 5 and which . ~ .
contains an energizing coil 7 with multiple windings to allow supply from a generally polyphased electrical source.
q~
The magneti¢ circuit, con~titutted by the ~tator houslng 6" is interrupted on it~ inner cylindrlcal ~all ~o as to preaent a multlpol~r ~ystem 60 con~t~tuted by a plurality oî teeth o~ which the alte~nate, generally imbricated arrangement determine~ along the generatrice~
air ~pace~ ~rhioh Qra the seat of a leakage ~lwc produced by ths ma~;netomotivs force o~ the coll and peripherallyr oriented by the direction oi~ the energizln~ current9 ~o ~ to eoop0rat0 ~ith the P~ oP the magnetized dipole~
o~ the rotor 11, Thi~ known arrEmgement, which i~ illuetratod in Fig~ O
2 and 3, doe~ not make it pos~ible, a~ will be ~3een her~
inafter, to increas~ the number o~ ~tep~ o~ Q g:Lven motor without lo~ o~ torque~ ~his i~ ~hy~ ~hen it i~ d~ired ~or a:~ample to double the numb~r oi~ step~ o~ a motor of giveIl size, the elementary ~tator fitructurc ~8tator hou-~ing 6'" cnergiz.ing coil 7') mu~t al~o be doubled Q~3 well a~ , o~ cour~e " the length o~ th~ rotor 1, in the proportion, ao 0hown in ~
~o e:~plain thie nec~sity, FigE3o 2 and 3 mu~t bo referred to, which ~ho,r howf in the multipolar syetem~ 60 Fl,nd 60 ~ ~ the reluctanc~ and tho ~ectlon o~ th~ ~t~tor polar t~th o~ ~ g:l~en motor evo~ ~rhon the ~tep :l0 r~
duced, f or a~nmple ~ by ha~ .
~h~ lelk.~e reluct~nco ~ o~ th~ ~ t;ator olrouît i~
qu~Mtion (Flg. 2) l~ invar~ely proportional to the ~cou-mulated ~u~ce~ OI the ~ide~ oll~ opposite polnr teeth ~nd proportlonal to the di~t~nc~ l 8epEIrating thea0 ~ldeG., ~3q``~3 For an ~delltical radial th.ickne~ o-~ tha ~tator polar piec0~, the opposit~ aoe~ e~ the polar tie~th ~idos are ~ub~tE~tiallg proportio~ to the l~ngth~ ~ oi the~e ~lde~ . -On the ether h~d (Figo 3~ ~rhen th~ number o~ step0i~ doubl~?d, by reducing th~ wldth o~ the polar lteeth bg hal~, the u~a~ul lron s~ctilon ~ 0,t tihe bace o:~ theoe teeth i.s con~equently 1~180 reduc~d by hale7 a~ ~ell a~ th~ lnt~
mediate dif~tanco ~2 ~
It ~ollowa that~ the len~th ~ o:~ the oppo~it~ teeth sidet3 remaining ~qu0.l, th0 ~tator reluotanoe dacr~a~e~
sub~tarltl~lly by hali. Thue,, the increa~ in the induoed ~lwl: ~, ~vers01y proportional to the r~luctano~, proYo kes the incre~3~ in the induction B - ~ and th~r~or~
saturation at the level o~ th~ ba~0 of tha polar taeth o~
reduced ~eotio~ ~ andJ by the limitation o:~ th0 leakag0 flu:1c between teeth whlch results thereIrom, a limitatlon OI the ma~ne-tic torque e:~certe~ on the rotor.
It ~ill there~ore be neces~ary, in order be~t to 20 eliminate the detrimental phenomenon oi caturation and to :Lmpro~0 the ~nerge~ic y~eld O:e the motor~ ~o recluce the height o~ th~ teeth ~ welï an the heigh t o:f the ro tor ~or ~ elv~n ma~snetomotiv~ :eorce ~urnl~hed by tho ~ame vo~
lum~ o:f cop~r o~ the co~l~
Thl~ ïowarine~ o~ the hei~ht o~ the mo-tor i~ lna~ta bly tr~n~31ated b~ an ~ppreciabl~ r~duction o:~ th~ motor torqu~,, partioularly :e~motion o~ thi~ hoi~lt (~bout 50 %
inafter, to increas~ the number o~ ~tep~ o~ Q g:Lven motor without lo~ o~ torque~ ~his i~ ~hy~ ~hen it i~ d~ired ~or a:~ample to double the numb~r oi~ step~ o~ a motor of giveIl size, the elementary ~tator fitructurc ~8tator hou-~ing 6'" cnergiz.ing coil 7') mu~t al~o be doubled Q~3 well a~ , o~ cour~e " the length o~ th~ rotor 1, in the proportion, ao 0hown in ~
~o e:~plain thie nec~sity, FigE3o 2 and 3 mu~t bo referred to, which ~ho,r howf in the multipolar syetem~ 60 Fl,nd 60 ~ ~ the reluctanc~ and tho ~ectlon o~ th~ ~t~tor polar t~th o~ ~ g:l~en motor evo~ ~rhon the ~tep :l0 r~
duced, f or a~nmple ~ by ha~ .
~h~ lelk.~e reluct~nco ~ o~ th~ ~ t;ator olrouît i~
qu~Mtion (Flg. 2) l~ invar~ely proportional to the ~cou-mulated ~u~ce~ OI the ~ide~ oll~ opposite polnr teeth ~nd proportlonal to the di~t~nc~ l 8epEIrating thea0 ~ldeG., ~3q``~3 For an ~delltical radial th.ickne~ o-~ tha ~tator polar piec0~, the opposit~ aoe~ e~ the polar tie~th ~idos are ~ub~tE~tiallg proportio~ to the l~ngth~ ~ oi the~e ~lde~ . -On the ether h~d (Figo 3~ ~rhen th~ number o~ step0i~ doubl~?d, by reducing th~ wldth o~ the polar lteeth bg hal~, the u~a~ul lron s~ctilon ~ 0,t tihe bace o:~ theoe teeth i.s con~equently 1~180 reduc~d by hale7 a~ ~ell a~ th~ lnt~
mediate dif~tanco ~2 ~
It ~ollowa that~ the len~th ~ o:~ the oppo~it~ teeth sidet3 remaining ~qu0.l, th0 ~tator reluotanoe dacr~a~e~
sub~tarltl~lly by hali. Thue,, the increa~ in the induoed ~lwl: ~, ~vers01y proportional to the r~luctano~, proYo kes the incre~3~ in the induction B - ~ and th~r~or~
saturation at the level o~ th~ ba~0 of tha polar taeth o~
reduced ~eotio~ ~ andJ by the limitation o:~ th0 leakag0 flu:1c between teeth whlch results thereIrom, a limitatlon OI the ma~ne-tic torque e:~certe~ on the rotor.
It ~ill there~ore be neces~ary, in order be~t to 20 eliminate the detrimental phenomenon oi caturation and to :Lmpro~0 the ~nerge~ic y~eld O:e the motor~ ~o recluce the height o~ th~ teeth ~ welï an the heigh t o:f the ro tor ~or ~ elv~n ma~snetomotiv~ :eorce ~urnl~hed by tho ~ame vo~
lum~ o:f cop~r o~ the co~l~
Thl~ ïowarine~ o~ the hei~ht o~ the mo-tor i~ lna~ta bly tr~n~31ated b~ an ~ppreciabl~ r~duction o:~ th~ motor torqu~,, partioularly :e~motion o~ thi~ hoi~lt (~bout 50 %
3~V~
~or a doubling o~ th0 number of ~-t~p~) which l~ad~ to oompen~atlng ~ lo~ by the additio~ o~ the ~ame ~ha~ o~
a ~upplementary motor e~h tim~ ~t i~ de0ired to doubl~
the number o~ ~tep~
It is preci~aly to avoid thi~ e2pensi~0 and ~ompli ca-tad multiplicatlon o~ tho elem~rlt~ oon~ltuting ~ gr~up o~ a plurality of motor~ with a l~rge number oP ~t~p~ that the invention pro~ido~ ho~m in Fig. 4, th~ interpo~l-tion, betwe~n two end ringB 60l 9 602 o~ ~tator polar te~th o~ a ~tep~ t~p motor with ~ing~.~ coil (not ~hown~9 o~
an intermediat~ ring 603 mad0 o~ ~erromagn~ti~ ~aterlal con~titut~d by a double ~eri~ oi polar teeth oppo~it~ by the ba~e and ln a number e~ual to that of the pole~ o~ th3 rotor and o~ tha ~-tatorO Each ~eriee o~ polar teeth o~ the intermediat~ pol~r pi~c~ has relati~ an~r e~ttin~
col~ciding with the ~ngular aettin~ oi tha dipole~ o~ the rotor, a~ well a~ w1th th~t o~ the and polar teeth oppo;
~ite the ~tator.
Thi~ in~ermediate rlng, who~e ~unction e~sentiall~
consi~ta in ~ubdi~iding the maenetic potential a.nd to ~ome extent in relaying b~tween the end polar t~eth o* the ~tator tho ~lux produced by th~ ~ouree o~ ma~ne-tomotl~ ~orce or, ln othar ~ord~l, ln dividin~ the magnetomoti~0 ~oI~oe ~pplied to the po~ o:~ the rotor, mnko~ it po~ibl~, by optimn~
ll7.1ng the rala~lve l~ngth and ~idth of th0 polar t~eth9 ~ ha~ been explalnod hervin~bove~ to aliMin~t~ the phono-monon o~ ~a~llration d0trlmental to m~lntain~ng the motor ~orque nt it~ maximum value.
~8~3 The ~ntermediate ring 603 i~ mechanlcallg malntained ln po~ition between thc ~nd ring~ on th~ lnner wall o~ th~
31n~1e coil by an appropriat0~ conv~ntional technologioal mean~ ~u¢h a~ ior e~ample by iorc~-iittlng, adhe~ion or inoert~on by oa~ting o~ the pla~tic~ mQterial con~titutln~
the 0hell oi the coil.
Theoretically, there i~ no llmit to the multiplica tion in coa~ial ~eri~ o~ th~ lnte~mediate ~tator ring~
603 in order to incr~a~e the torqu~ at the ~ame tim~ a~ the length oi the motor and it3 constituent ~le~ento (~ingl~
coil, multipolar rotor7 otator hou~ing), increa~e~, Flnally, it mu~t b~ coneidered that each lntermediat~
ring 60~ ~ith doublc sorieo oi polar teeth (who~e ~hape and relative angular 8ett~ng are det~rmined only by th~ lncli natio~ or ~ngular o~tting o~ tho rotor dipolar generatrice8) conatitutea an au~iliary 0tator encrgized in ~oriea bg ~he ma&netomotivo ~orce o~ the oingle coil.
Thie arraneemcnt ~orming the subject matter o~ the invention, assentially make~ it po~ible to avoid the oatu-ratlon o~ the polar teeth o~ reducad ~e¢tlon by the leakageflux circulating in ~he spaces between teeth.
Undor the~e condition~, it 1~ pos~ibl~ ~imply and aconomically to lnorea~ the re~olution oP a ctep~by-~tep mo~or o~ gl~n type with doublo directlon o~ rotation, by increQ~:In the number oP it~ ~ta~or polar teeth, without a~eçtlng the el00tr.0mechanlo~1 oharacteri~tico thereo
~or a doubling o~ th0 number of ~-t~p~) which l~ad~ to oompen~atlng ~ lo~ by the additio~ o~ the ~ame ~ha~ o~
a ~upplementary motor e~h tim~ ~t i~ de0ired to doubl~
the number o~ ~tep~
It is preci~aly to avoid thi~ e2pensi~0 and ~ompli ca-tad multiplicatlon o~ tho elem~rlt~ oon~ltuting ~ gr~up o~ a plurality of motor~ with a l~rge number oP ~t~p~ that the invention pro~ido~ ho~m in Fig. 4, th~ interpo~l-tion, betwe~n two end ringB 60l 9 602 o~ ~tator polar te~th o~ a ~tep~ t~p motor with ~ing~.~ coil (not ~hown~9 o~
an intermediat~ ring 603 mad0 o~ ~erromagn~ti~ ~aterlal con~titut~d by a double ~eri~ oi polar teeth oppo~it~ by the ba~e and ln a number e~ual to that of the pole~ o~ th3 rotor and o~ tha ~-tatorO Each ~eriee o~ polar teeth o~ the intermediat~ pol~r pi~c~ has relati~ an~r e~ttin~
col~ciding with the ~ngular aettin~ oi tha dipole~ o~ the rotor, a~ well a~ w1th th~t o~ the and polar teeth oppo;
~ite the ~tator.
Thi~ in~ermediate rlng, who~e ~unction e~sentiall~
consi~ta in ~ubdi~iding the maenetic potential a.nd to ~ome extent in relaying b~tween the end polar t~eth o* the ~tator tho ~lux produced by th~ ~ouree o~ ma~ne-tomotl~ ~orce or, ln othar ~ord~l, ln dividin~ the magnetomoti~0 ~oI~oe ~pplied to the po~ o:~ the rotor, mnko~ it po~ibl~, by optimn~
ll7.1ng the rala~lve l~ngth and ~idth of th0 polar t~eth9 ~ ha~ been explalnod hervin~bove~ to aliMin~t~ the phono-monon o~ ~a~llration d0trlmental to m~lntain~ng the motor ~orque nt it~ maximum value.
~8~3 The ~ntermediate ring 603 i~ mechanlcallg malntained ln po~ition between thc ~nd ring~ on th~ lnner wall o~ th~
31n~1e coil by an appropriat0~ conv~ntional technologioal mean~ ~u¢h a~ ior e~ample by iorc~-iittlng, adhe~ion or inoert~on by oa~ting o~ the pla~tic~ mQterial con~titutln~
the 0hell oi the coil.
Theoretically, there i~ no llmit to the multiplica tion in coa~ial ~eri~ o~ th~ lnte~mediate ~tator ring~
603 in order to incr~a~e the torqu~ at the ~ame tim~ a~ the length oi the motor and it3 constituent ~le~ento (~ingl~
coil, multipolar rotor7 otator hou~ing), increa~e~, Flnally, it mu~t b~ coneidered that each lntermediat~
ring 60~ ~ith doublc sorieo oi polar teeth (who~e ~hape and relative angular 8ett~ng are det~rmined only by th~ lncli natio~ or ~ngular o~tting o~ tho rotor dipolar generatrice8) conatitutea an au~iliary 0tator encrgized in ~oriea bg ~he ma&netomotivo ~orce o~ the oingle coil.
Thie arraneemcnt ~orming the subject matter o~ the invention, assentially make~ it po~ible to avoid the oatu-ratlon o~ the polar teeth o~ reducad ~e¢tlon by the leakageflux circulating in ~he spaces between teeth.
Undor the~e condition~, it 1~ pos~ibl~ ~imply and aconomically to lnorea~ the re~olution oP a ctep~by-~tep mo~or o~ gl~n type with doublo directlon o~ rotation, by increQ~:In the number oP it~ ~ta~or polar teeth, without a~eçtlng the el00tr.0mechanlo~1 oharacteri~tico thereo
Claims (3)
1. A step-by-step motor comprising:
a stator having an energizing coil for producing a magnetomotive force;
a rotor surrounded by the stator and having an axis about which the rotor is rotatable, said rotor having a circumferential periphery and a succession of alternate magnetic dipoles disposed along its circumferential periphery and to which the magnetomotive force of the coil is applied;
a bearing which is positionally fixed with respect to the stator and through which the axis of the rotor passes;
wherein the stator includes an inner cylindrical wall adapted for dividing the magnetomotive force of the coil applied to the magnetic dipoles of the rotor and comprising two end rings having polar teeth in a number equal to that of the magnetic dipoles of the rotor, and at least an inter-mediate ring disposed between the two end rings and made of ferromagnetic material, said intermediate ring being secured to an inner wall of the coil and comprising two annular rows of polar teeth, the teeth of each row being angularly offset between the teeth in the other row, the number of the teeth of each row being equal to the number of the teeth of the end rings and to the number of the dipoles of the rotor.
a stator having an energizing coil for producing a magnetomotive force;
a rotor surrounded by the stator and having an axis about which the rotor is rotatable, said rotor having a circumferential periphery and a succession of alternate magnetic dipoles disposed along its circumferential periphery and to which the magnetomotive force of the coil is applied;
a bearing which is positionally fixed with respect to the stator and through which the axis of the rotor passes;
wherein the stator includes an inner cylindrical wall adapted for dividing the magnetomotive force of the coil applied to the magnetic dipoles of the rotor and comprising two end rings having polar teeth in a number equal to that of the magnetic dipoles of the rotor, and at least an inter-mediate ring disposed between the two end rings and made of ferromagnetic material, said intermediate ring being secured to an inner wall of the coil and comprising two annular rows of polar teeth, the teeth of each row being angularly offset between the teeth in the other row, the number of the teeth of each row being equal to the number of the teeth of the end rings and to the number of the dipoles of the rotor.
2. The step-by-step motor according to Claim 1, wherein said intermediate ring has a median plane and wherein said two annular rows are disposed on opposite sides of said median plane, and wherein the polar teeth in said annular rows have a shape and a dimension similar to a shape and a dimension of the polar teeth of said two end rings.
3. The step-by-step motor according to Claim 2, wherein each annular row of polar teeth in said intermediate ring have relative angular positions corresponding with angular positions of the magnetic dipoles of said rotor and angular settings of the polar teeth in said two end rings.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8009182 | 1980-04-23 | ||
| FR8009182A FR2481535A1 (en) | 1980-04-23 | 1980-04-23 | IMPROVEMENT FOR MULTIPOLAR MAGNET STEP MOTORS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1180043A true CA1180043A (en) | 1984-12-27 |
Family
ID=9241296
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000375904A Expired CA1180043A (en) | 1980-04-23 | 1981-04-22 | Multipolar stepping motor with intermediate stator rings |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0038739A1 (en) |
| JP (1) | JPS57101556A (en) |
| CA (1) | CA1180043A (en) |
| ES (1) | ES501215A0 (en) |
| FR (1) | FR2481535A1 (en) |
| IE (1) | IE52521B1 (en) |
| MX (1) | MX149232A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63241534A (en) * | 1987-03-30 | 1988-10-06 | Toshiba Corp | Image reader |
| DE102020209303A1 (en) * | 2020-07-23 | 2022-01-27 | Brose Fahrzeugteile SE & Co. Kommanditgesellschaft, Coburg | Actuator for adjusting a vehicle assembly |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB137255A (en) * | 1919-02-14 | 1920-01-08 | Charles Leslie Walker | Improvements in and connected with electro-magnetic step-by-step and like mechanism |
| FR1377302A (en) * | 1963-05-30 | 1964-11-06 | Crouzet Sa | Improvement of the starting torque of single-phase synchronous motors |
| DE1538180A1 (en) * | 1964-10-22 | 1970-02-05 | Teldix Gmbh | Single-phase synchronous motor with permanent magnet rotor |
| FR1452023A (en) * | 1965-03-19 | 1966-02-25 | Carpano & Pons | Synchronous electric motor |
| CH544441A (en) * | 1971-10-21 | 1973-11-15 | Saia Ag | Small synchronous motor with direction of rotation preselection |
| US3755701A (en) * | 1972-09-14 | 1973-08-28 | Gen Motors Corp | Selectively reversible step motor |
| FR2214990B1 (en) * | 1973-01-18 | 1976-05-14 | Lip Horlogerie |
-
1980
- 1980-04-23 FR FR8009182A patent/FR2481535A1/en active Granted
-
1981
- 1981-04-09 EP EP81400563A patent/EP0038739A1/en not_active Ceased
- 1981-04-09 ES ES501215A patent/ES501215A0/en active Granted
- 1981-04-22 CA CA000375904A patent/CA1180043A/en not_active Expired
- 1981-04-22 MX MX18696681A patent/MX149232A/en unknown
- 1981-04-23 IE IE90581A patent/IE52521B1/en unknown
- 1981-04-23 JP JP6071481A patent/JPS57101556A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| FR2481535B1 (en) | 1983-02-04 |
| IE52521B1 (en) | 1987-12-09 |
| ES8203539A1 (en) | 1982-04-01 |
| EP0038739A1 (en) | 1981-10-28 |
| JPS57101556A (en) | 1982-06-24 |
| IE810905L (en) | 1981-10-23 |
| ES501215A0 (en) | 1982-04-01 |
| FR2481535A1 (en) | 1981-10-30 |
| MX149232A (en) | 1983-09-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |