CA1135759A - Stepping motor with permanent magnet in the stator and rotor teeth arranged helically - Google Patents
Stepping motor with permanent magnet in the stator and rotor teeth arranged helicallyInfo
- Publication number
- CA1135759A CA1135759A CA000354170A CA354170A CA1135759A CA 1135759 A CA1135759 A CA 1135759A CA 000354170 A CA000354170 A CA 000354170A CA 354170 A CA354170 A CA 354170A CA 1135759 A CA1135759 A CA 1135759A
- Authority
- CA
- Canada
- Prior art keywords
- teeth
- rotor
- stator
- systems
- stepping motor
- 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
- H02K37/20—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 rotating flux distributors, the armatures and magnets both being stationary
-
- 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
- H02K21/38—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with rotating flux distributors, and armatures and magnets both stationary
- H02K21/44—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with rotating flux distributors, and armatures and magnets both stationary with armature windings wound upon the magnets
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Iron Core Of Rotating Electric Machines (AREA)
- Control Of Stepping Motors (AREA)
- Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
Abstract
3.3.1980 1 PHN 9492 ABSTRACT:
A stepping motor with axially spaced annular stator sections which each comprise an annular coil and on the inner side each terminate in annular systems of teeth which cooperates with rotor teeth. A simple and accurate alignment of the various teeth can be obtained by axially aligning the stator teeth and arranging the rotor teeth helically.
A stepping motor with axially spaced annular stator sections which each comprise an annular coil and on the inner side each terminate in annular systems of teeth which cooperates with rotor teeth. A simple and accurate alignment of the various teeth can be obtained by axially aligning the stator teeth and arranging the rotor teeth helically.
Description
5~
This invention relates to a stepping motor having a stator which at least comprises a first annular stator section with an annular coil and a magnetically conductive enclosure surrounding said annular coil, which enclosure terminates in a first and a second annular system of teeth, a second annular stator section having an annular coil and a magnetically conductive enclosure surrounding said annular coil, which enclosure terminates in a third and a fourth annular system of teeth, and a rotor having a toothing which cooperates with the first, the second, the third and the fourth system of teeth.
Such a stepping motor is known from my Netherlands Patent Application no. 7701510 which was laid open to public inspection on August 16, 1978 and is extremely suitable for use as a stepping motor with a small stepping angle, for example 1.8~, i.e.200 steps per rotor revolution. In order to avoid excessive stepping-angle errors with such a stepping motor the alignment of the systems of stator teeth relative to the rotor toothing should comply with very stringent requirements J which requirements in the case of series production may lead to a substantial increase in costs. In addition, it may be advantageous to introduce specific deviations in the nominal mutual positions o-f the rotor toothing relative to the stator toothing, as is described in my Canadian Application No. 35~,169 which has been filed simultaneously with the present application.
It is ~he object of the invention to provide a stepping motor of the type mentioned in the preamble, which can be aligned accurately in a comparatively easy manner.
~L3~S~
. ~
3.3.1~80 2 PHN 9492 To this end the invention is characterized in that the teeth of the systems of stator teeth are disposed axially in line and that the teeth of the rotor toothing are located at the circumference of the rotor in that helical grooves are formed in the rotor surface.
The invention is based on the recognition that it is comparatively simple to align the stator teeth in an axial direction and that, because the rotor toothing has a helical structuret the tangential location of the rotor toothing relative to the stator toothing is dictated by axial distances.
A first advantageous embo`diment is characterized in that the teeth of the rotor toothing are smaller in respect of their axial height than those of the systems of stator teeth cooperating therewith and that the teeth of the system o~ stator teeth axially overlap the rotor teeth which cooperate therewith in both direc-tions.
In this embodiment the tangen-tial alignment is determined by the location of the axial boundaries of the rotor teeth. This embodiment may further be characterized in that there is provided a first~ second, third and fourth system of rotor teeth, which cooperate with the first, the second, the third and ~tha fourth system of stator teeth respectively~ which ~ystems of rotor teeth are formed in that in addition to said helical grooves there are also formed circular grooves, which bound the said systems of rotor teeth in the axial direction. ~s a resul-t of this the tangen-tial alignment of the motor is determined by the location of said circular grooves~ This location can simp~y be changed during series production.
~n alternative advantageous embodiment may be characterized in that the teeth of the systems of stator teeth are smaller in respect of the axial height than -those of the rotor toothing cooperating , 3.3.1980 3 PHN 9~92 therewith and that the teeth o~ the rotor toothing --axially overlap the cooperating teeth of the systems of stator teeth in both directions.
In this embodiment the tangential alignment is determined by the location of the axial boundaries o~ the systems of stator teeth.
The invention will be described in more detail with reference to the drawing, of which Fig. 1 shows an axial cross-section o~ a stepping motor in accordance with the inven-tion, Fig. 2 is a perspective view of a disassembled stepping motor in accordance with the invention showing the stator in axial cross-section, Fig. 3 schematically shows the location of the stator teeth relative to the rotor teeth in a first embodiment of a stepping motor in accordance with Figures 1 and 2, and Fig. 4 schematically shows the 2q location o~ the stator teeth relative to the rotor teeth in a second embodiment of a stepping motor in acoordance with ~igs. 1 and 2.
Fig. 1 shows an axial cross-section of a stepping motor employing the inventive 25principle, and Fig. 2 shows said motor disassembled and in perspecti~e with the stator in axial cross section. The stepping motor is substantially rotationsymmetrical about the axis A-AI and comprises a rotor 1 and a stator 2. ~he stator comprises two coaxial stator sections 3 and 4 with coaxially interposed between said sections an axially magnetized permanent-magnetic ring 5. ~ach of the stator sections 3 and ~ respectively comprises a coaxially ~isposed annular coil 8 and 9 respectively surrounded by a 3 magnetically conductive enclosure 6 and 7 respectively, which enclosure on the inner side terminates in two annular systems of teeth 10, 11 and 12, 13 respectively.
The rotor 1 is provided with the annular systems of teeth ~35~
3.3~1980 4 PHN 9~92 14, 15, 16 and 17 which cooperate with the annular systems of teeth 10, 11, 12 and 13 respectively. As can be seen in Fig. 2 said rotor teeth are bounded by helical grooves 9 one of said grooves being represented by dashed lines 180 The alignmen-t is then such that the teeth of the systems of stator teeth 10, 1~1, 12 and 13 are axially in line and that if the teeth of the systems of rotor teeth 1~ are disposed opposite the teeth of the system of stator teeth 10 the teeth of the systems of stator teeth 11, 12 and 10 13 are shifted relative to the systems of rotor teeth 15, 16 and 17 by 1800, 90 and 270 respectively ~or alternati-vely 180, 270 and 90 respectively), 3600 corresponding to one tooth pitch.
The axiall.y magnetized permanent ~5 magnetic ring magnetizes the systems of teeth 10 and 11 with a specific polarity and the systems of teeth 12 and 13 with an opposite polarity. ~or a specific direction o~ the current through the annular coil 8 or 9 the field as a result o~ the energization in the air gap between stator 20 and rotor associated with the system of teeth 10 and 12 respectively then has the same direction as the fiald caused in said air gap by the permanent magnetic ring and is opposed thereto in the other air gap associated with the system of teeth 11 or 13 respectively. For the opposite 25 direotion of the current $hrough the annular coil 8 or 9 the field as a result of said energization in the air gap between stator and rotor associated with the respec-tive system of teeth 11 or 13 has the same direction as the field produced in said air gap by the permanant magnetic 30 ring and i9 oppo~ed thereto in the other air gap associated with the respective system of teeth 10 or 12. By the choice o~ the energ~æing direction of the current in each time one or each time both coi~s 8 and 9, each time one or each time two rotor-stator teeth systems can produce a torque, so 5 that it is possible to drive the rotor stepwise in steps with a magnitude of 1/l~ tooth pitch.
In this respect it is to be ~ ~S7S~
3.3.1980 5 PHN 9492 noted that the loca-tion of the permanent magnet in the stator is not very essential. This permanent magnet may for example also be inc orporated in the rotor at a location designated 5l in Fig. 1 or may for example surround the two stator sections 3 and 4 as a cylindrical sleeve. Alternatively, the permanent magnet may in principle be replaced by a d.c, energized coil.
Fig. 3a schematically repre-sents a de~elopment of a part of the rotor toothing showing the position of each time two teeth of each system of stator teeth 10, 11, 12 and 13. When the distance between these systems o~ stator teeth in combination wi-th the angle relative to the axis at which the rotor teeth are located, which in the de~elopment are situated on an oblique row~ has been selected correctly, then, if the teeth of sy~tem of stator teeth 10 are situated opposite the teeth of the system of rotor teeth 14 (defined as an angle of 0 between the two systems)~ the teeth of the system of stator teeth 11 are situated exactly between the teeth of the system of rotor teeth 15 (de~ined as an angle of 180 between the two systams), the teeth of the system of stator teeth 12 are situated halfway opposite the teeth of the system of rotor teeth 16 ~defined as an angle of 90 between the two systems of teeth)~ and the teeth of the system of stator teeth 13 are situated halfway opposite the teeth of the system of rotor teeth 17 (defined as an angle of 270 between the two systems of teeth).
In the situation as shown in Fig. 3a, the rotor teeth extend in an axial direction beyond the stator teeth. In principle this ma~ be extended so far that the teeth of the various systems of stator teeth 14, 15, 16 and 17 adjoin each other and form helical ridges which e~tend between the two end faces o~ the rotor. However, in order to reduce the mass moment of inertia of the rotor it is generally advantageous to minimize the rotor -teeth height hr (see Fig~ 3b).
In order to illustrate the 1~3~i~5~
3.3.1980 6 PHN 9492 effect of a rotor-stator teeth system construction as sho~n in Fig. 3a on the tangential alignment of the systems of teeth relative to each other, Fig. 3b shows a rotor teeth tr with opposite thereto a stator tooth ts, and Fig. 3c the same configuration in which, relative to the situation in Fig. 3~ a stator teeth has been shifted over a dis-tance x in an axial direction with the same -position of the rotor tooth tr. In Fig. 3b the centre aS
of the stator tooth tS is situated at a distance 2Y to the right of the centre line br of the rotor tooth tr. After shi~ting the stator tooth ts over a distance x in an axial direction (Fig. 3c), the centre aS of stator teeth ts is located at a distance ~y to the left of the centre line br of the rotor tooth tr. Thus, a shift of the stator tooth tS over a distance x in an axial direction results in a shift y of the stator tooth relative to the rotor tooth in *he tangential directionO In this way the tangential alignment (positioning o~ the stator systems relative to the rotor toothing at correct angles) is determined by the axial distances between the systems of stator teeth, which axial alignment can be realized far more simply than a tangential alignment. An additional advantage may ba that the ratio y/x is equal to the tangent of the angle &~ which the centre line of the rotor tooth ma~es with that of the stator tooth~ If this angle is smaller than 45, a displacement x in an axial direction results in a smaller displacement y in a tangential direction, so that a speci-fic tolerance in y corresponds to a greater tolerance in x.
Fig. 4a shows a similar situation as Fig. 3a, but with ~tator teeth which extend axially beyond the rotor teeth~ Fig. 4b shows a rotor tooth tr of the oonfiguration of Fig. 4a for a specific position with superpused on it a stator tooth ts~ and Fig. 4c ~hows the same situation but with a shift over a distance x in the direction of the helix along which it is situated, in that the two planes which bound the system of ~5759 3.3,1C~80 7 PHN 94'~2 rotor teeth to which the tooth tt belongs have been shifted over a distaslce x ia an axial direction. In the situation of Figo 4b the centre a of rotor tooth tr is located at a distance 2Y to the left of the centre line bs of the stator tooth ts, A displacement of the rotor tooth ~ong the ~Yis on which it is located over an axial distance x results in the situation of Fig. 4c, where the centre ar of said rotor tooth is situated at a distance 2Y
to the right of the centre lLne bs of stator tooth ts (as 10 the smallest tooth determines the mutual position of the two teeth, ths mutual tangential position of two teeth is defined by the tangential distanca between the centre line of the longer tooth and the centre of the shorter tooth).
A shi~t of the axial bounding 15 surfaces of the systems of rotor teeth over a distance x thus results in a shift y of the stator tooth relative to the rotor tooth in a tangential direction. In this way the tangential alignment is determined by the axial distances between the systems of rotor teeth.
In the situation shown in Fig. 3 the height hr of the rotor teeth has been selected greater than the height h5 of the stator teet~ the stator teeth being within the height of the rotor teeth in respect of their height. With this solution the axial alignment of 25 the stator sections, i,e. the axial distances betwe~n the systems of stator t,eeth 10 through 139 determines the tangential alignmen-t and the location of the surfaces which bound the systems of rotor teeth 14 through 17 in an axial direction is no-critical. In the situation shown in Fig. 4 30 this is exactly the other way round. In this case the height hr of the systems of rotor teeth 14 through 17 ~alls within the height h9 of the stator teeth and the surfaces which bound the systems of rotor teeth in an aYial direction determine the axial alignment, whereas the axial 35 distance~ between the systems of stator teeth are non-critical. However, in principle it is also possible to select for example hr = hs- The axial location of both the ~35~5~
3.3.1980 8 PHN 9492 systems of stator teeth and the systems of rotor teeth then determines the tangential alignment. Moreover, an incorrect location not only influences the alignment but also the magni-tude of the torques, because thc part of the height o~ the stator and rotor teeth which is common i~
respect of the axial location, which cornmon part in this case has become dependent on the axial location of the two systems of teeth relative to each other, determines the torque. Therefore 5 it is to be referred to select the height of either the rotor or the stator teeth smaller than that of the other o~ the two and to ensure that the relevant teeth in respect of the height on both axial sides are situated within the a~ial sides of the other teeth.
A rotor of a motor in accordan-ce with the invention can simply be manufactured by forming helical grooves in a cylindrical body~ for example, by moving a milling-tool over the surfaca of the oylinder in an axial direction whilst rotating said cylinder. If separate systems of teeth are required on said rotor the material between said systems of teeth ma~ be removed previously or subsequently by means of a suitable operation.
In the case shown in Fig. 4 the location where said materi-- al is removed~ for example turned of~ determines the tangential align~ent of the rotor relative to the stator.
This method then has the advantage that it is comparatively sirnple to change this alignment during series production by selecting a different setting of the machine tool used, for ex.ample a lathe. An alternative is to start from a rotor construction as shown in Fig. 2, but without the nelical grooves defining the teeth~ and to form these grooves in all four systems of teeth in one operation.
The invention is not limited to the embodiment shown. In addition to the hybrid stepping 35 motor shown, the inventive princip e is also applicable to a reluctance stepping motor of similar construction as the hybrid stepping motor shown, i.e. to any motor with a~ially spaced annular and ro-tation-symmetrical systems of teeth.
This invention relates to a stepping motor having a stator which at least comprises a first annular stator section with an annular coil and a magnetically conductive enclosure surrounding said annular coil, which enclosure terminates in a first and a second annular system of teeth, a second annular stator section having an annular coil and a magnetically conductive enclosure surrounding said annular coil, which enclosure terminates in a third and a fourth annular system of teeth, and a rotor having a toothing which cooperates with the first, the second, the third and the fourth system of teeth.
Such a stepping motor is known from my Netherlands Patent Application no. 7701510 which was laid open to public inspection on August 16, 1978 and is extremely suitable for use as a stepping motor with a small stepping angle, for example 1.8~, i.e.200 steps per rotor revolution. In order to avoid excessive stepping-angle errors with such a stepping motor the alignment of the systems of stator teeth relative to the rotor toothing should comply with very stringent requirements J which requirements in the case of series production may lead to a substantial increase in costs. In addition, it may be advantageous to introduce specific deviations in the nominal mutual positions o-f the rotor toothing relative to the stator toothing, as is described in my Canadian Application No. 35~,169 which has been filed simultaneously with the present application.
It is ~he object of the invention to provide a stepping motor of the type mentioned in the preamble, which can be aligned accurately in a comparatively easy manner.
~L3~S~
. ~
3.3.1~80 2 PHN 9492 To this end the invention is characterized in that the teeth of the systems of stator teeth are disposed axially in line and that the teeth of the rotor toothing are located at the circumference of the rotor in that helical grooves are formed in the rotor surface.
The invention is based on the recognition that it is comparatively simple to align the stator teeth in an axial direction and that, because the rotor toothing has a helical structuret the tangential location of the rotor toothing relative to the stator toothing is dictated by axial distances.
A first advantageous embo`diment is characterized in that the teeth of the rotor toothing are smaller in respect of their axial height than those of the systems of stator teeth cooperating therewith and that the teeth of the system o~ stator teeth axially overlap the rotor teeth which cooperate therewith in both direc-tions.
In this embodiment the tangen-tial alignment is determined by the location of the axial boundaries of the rotor teeth. This embodiment may further be characterized in that there is provided a first~ second, third and fourth system of rotor teeth, which cooperate with the first, the second, the third and ~tha fourth system of stator teeth respectively~ which ~ystems of rotor teeth are formed in that in addition to said helical grooves there are also formed circular grooves, which bound the said systems of rotor teeth in the axial direction. ~s a resul-t of this the tangen-tial alignment of the motor is determined by the location of said circular grooves~ This location can simp~y be changed during series production.
~n alternative advantageous embodiment may be characterized in that the teeth of the systems of stator teeth are smaller in respect of the axial height than -those of the rotor toothing cooperating , 3.3.1980 3 PHN 9~92 therewith and that the teeth o~ the rotor toothing --axially overlap the cooperating teeth of the systems of stator teeth in both directions.
In this embodiment the tangential alignment is determined by the location of the axial boundaries o~ the systems of stator teeth.
The invention will be described in more detail with reference to the drawing, of which Fig. 1 shows an axial cross-section o~ a stepping motor in accordance with the inven-tion, Fig. 2 is a perspective view of a disassembled stepping motor in accordance with the invention showing the stator in axial cross-section, Fig. 3 schematically shows the location of the stator teeth relative to the rotor teeth in a first embodiment of a stepping motor in accordance with Figures 1 and 2, and Fig. 4 schematically shows the 2q location o~ the stator teeth relative to the rotor teeth in a second embodiment of a stepping motor in acoordance with ~igs. 1 and 2.
Fig. 1 shows an axial cross-section of a stepping motor employing the inventive 25principle, and Fig. 2 shows said motor disassembled and in perspecti~e with the stator in axial cross section. The stepping motor is substantially rotationsymmetrical about the axis A-AI and comprises a rotor 1 and a stator 2. ~he stator comprises two coaxial stator sections 3 and 4 with coaxially interposed between said sections an axially magnetized permanent-magnetic ring 5. ~ach of the stator sections 3 and ~ respectively comprises a coaxially ~isposed annular coil 8 and 9 respectively surrounded by a 3 magnetically conductive enclosure 6 and 7 respectively, which enclosure on the inner side terminates in two annular systems of teeth 10, 11 and 12, 13 respectively.
The rotor 1 is provided with the annular systems of teeth ~35~
3.3~1980 4 PHN 9~92 14, 15, 16 and 17 which cooperate with the annular systems of teeth 10, 11, 12 and 13 respectively. As can be seen in Fig. 2 said rotor teeth are bounded by helical grooves 9 one of said grooves being represented by dashed lines 180 The alignmen-t is then such that the teeth of the systems of stator teeth 10, 1~1, 12 and 13 are axially in line and that if the teeth of the systems of rotor teeth 1~ are disposed opposite the teeth of the system of stator teeth 10 the teeth of the systems of stator teeth 11, 12 and 10 13 are shifted relative to the systems of rotor teeth 15, 16 and 17 by 1800, 90 and 270 respectively ~or alternati-vely 180, 270 and 90 respectively), 3600 corresponding to one tooth pitch.
The axiall.y magnetized permanent ~5 magnetic ring magnetizes the systems of teeth 10 and 11 with a specific polarity and the systems of teeth 12 and 13 with an opposite polarity. ~or a specific direction o~ the current through the annular coil 8 or 9 the field as a result o~ the energization in the air gap between stator 20 and rotor associated with the system of teeth 10 and 12 respectively then has the same direction as the fiald caused in said air gap by the permanent magnetic ring and is opposed thereto in the other air gap associated with the system of teeth 11 or 13 respectively. For the opposite 25 direotion of the current $hrough the annular coil 8 or 9 the field as a result of said energization in the air gap between stator and rotor associated with the respec-tive system of teeth 11 or 13 has the same direction as the field produced in said air gap by the permanant magnetic 30 ring and i9 oppo~ed thereto in the other air gap associated with the respective system of teeth 10 or 12. By the choice o~ the energ~æing direction of the current in each time one or each time both coi~s 8 and 9, each time one or each time two rotor-stator teeth systems can produce a torque, so 5 that it is possible to drive the rotor stepwise in steps with a magnitude of 1/l~ tooth pitch.
In this respect it is to be ~ ~S7S~
3.3.1980 5 PHN 9492 noted that the loca-tion of the permanent magnet in the stator is not very essential. This permanent magnet may for example also be inc orporated in the rotor at a location designated 5l in Fig. 1 or may for example surround the two stator sections 3 and 4 as a cylindrical sleeve. Alternatively, the permanent magnet may in principle be replaced by a d.c, energized coil.
Fig. 3a schematically repre-sents a de~elopment of a part of the rotor toothing showing the position of each time two teeth of each system of stator teeth 10, 11, 12 and 13. When the distance between these systems o~ stator teeth in combination wi-th the angle relative to the axis at which the rotor teeth are located, which in the de~elopment are situated on an oblique row~ has been selected correctly, then, if the teeth of sy~tem of stator teeth 10 are situated opposite the teeth of the system of rotor teeth 14 (defined as an angle of 0 between the two systems)~ the teeth of the system of stator teeth 11 are situated exactly between the teeth of the system of rotor teeth 15 (de~ined as an angle of 180 between the two systams), the teeth of the system of stator teeth 12 are situated halfway opposite the teeth of the system of rotor teeth 16 ~defined as an angle of 90 between the two systems of teeth)~ and the teeth of the system of stator teeth 13 are situated halfway opposite the teeth of the system of rotor teeth 17 (defined as an angle of 270 between the two systems of teeth).
In the situation as shown in Fig. 3a, the rotor teeth extend in an axial direction beyond the stator teeth. In principle this ma~ be extended so far that the teeth of the various systems of stator teeth 14, 15, 16 and 17 adjoin each other and form helical ridges which e~tend between the two end faces o~ the rotor. However, in order to reduce the mass moment of inertia of the rotor it is generally advantageous to minimize the rotor -teeth height hr (see Fig~ 3b).
In order to illustrate the 1~3~i~5~
3.3.1980 6 PHN 9492 effect of a rotor-stator teeth system construction as sho~n in Fig. 3a on the tangential alignment of the systems of teeth relative to each other, Fig. 3b shows a rotor teeth tr with opposite thereto a stator tooth ts, and Fig. 3c the same configuration in which, relative to the situation in Fig. 3~ a stator teeth has been shifted over a dis-tance x in an axial direction with the same -position of the rotor tooth tr. In Fig. 3b the centre aS
of the stator tooth tS is situated at a distance 2Y to the right of the centre line br of the rotor tooth tr. After shi~ting the stator tooth ts over a distance x in an axial direction (Fig. 3c), the centre aS of stator teeth ts is located at a distance ~y to the left of the centre line br of the rotor tooth tr. Thus, a shift of the stator tooth tS over a distance x in an axial direction results in a shift y of the stator tooth relative to the rotor tooth in *he tangential directionO In this way the tangential alignment (positioning o~ the stator systems relative to the rotor toothing at correct angles) is determined by the axial distances between the systems of stator teeth, which axial alignment can be realized far more simply than a tangential alignment. An additional advantage may ba that the ratio y/x is equal to the tangent of the angle &~ which the centre line of the rotor tooth ma~es with that of the stator tooth~ If this angle is smaller than 45, a displacement x in an axial direction results in a smaller displacement y in a tangential direction, so that a speci-fic tolerance in y corresponds to a greater tolerance in x.
Fig. 4a shows a similar situation as Fig. 3a, but with ~tator teeth which extend axially beyond the rotor teeth~ Fig. 4b shows a rotor tooth tr of the oonfiguration of Fig. 4a for a specific position with superpused on it a stator tooth ts~ and Fig. 4c ~hows the same situation but with a shift over a distance x in the direction of the helix along which it is situated, in that the two planes which bound the system of ~5759 3.3,1C~80 7 PHN 94'~2 rotor teeth to which the tooth tt belongs have been shifted over a distaslce x ia an axial direction. In the situation of Figo 4b the centre a of rotor tooth tr is located at a distance 2Y to the left of the centre line bs of the stator tooth ts, A displacement of the rotor tooth ~ong the ~Yis on which it is located over an axial distance x results in the situation of Fig. 4c, where the centre ar of said rotor tooth is situated at a distance 2Y
to the right of the centre lLne bs of stator tooth ts (as 10 the smallest tooth determines the mutual position of the two teeth, ths mutual tangential position of two teeth is defined by the tangential distanca between the centre line of the longer tooth and the centre of the shorter tooth).
A shi~t of the axial bounding 15 surfaces of the systems of rotor teeth over a distance x thus results in a shift y of the stator tooth relative to the rotor tooth in a tangential direction. In this way the tangential alignment is determined by the axial distances between the systems of rotor teeth.
In the situation shown in Fig. 3 the height hr of the rotor teeth has been selected greater than the height h5 of the stator teet~ the stator teeth being within the height of the rotor teeth in respect of their height. With this solution the axial alignment of 25 the stator sections, i,e. the axial distances betwe~n the systems of stator t,eeth 10 through 139 determines the tangential alignmen-t and the location of the surfaces which bound the systems of rotor teeth 14 through 17 in an axial direction is no-critical. In the situation shown in Fig. 4 30 this is exactly the other way round. In this case the height hr of the systems of rotor teeth 14 through 17 ~alls within the height h9 of the stator teeth and the surfaces which bound the systems of rotor teeth in an aYial direction determine the axial alignment, whereas the axial 35 distance~ between the systems of stator teeth are non-critical. However, in principle it is also possible to select for example hr = hs- The axial location of both the ~35~5~
3.3.1980 8 PHN 9492 systems of stator teeth and the systems of rotor teeth then determines the tangential alignment. Moreover, an incorrect location not only influences the alignment but also the magni-tude of the torques, because thc part of the height o~ the stator and rotor teeth which is common i~
respect of the axial location, which cornmon part in this case has become dependent on the axial location of the two systems of teeth relative to each other, determines the torque. Therefore 5 it is to be referred to select the height of either the rotor or the stator teeth smaller than that of the other o~ the two and to ensure that the relevant teeth in respect of the height on both axial sides are situated within the a~ial sides of the other teeth.
A rotor of a motor in accordan-ce with the invention can simply be manufactured by forming helical grooves in a cylindrical body~ for example, by moving a milling-tool over the surfaca of the oylinder in an axial direction whilst rotating said cylinder. If separate systems of teeth are required on said rotor the material between said systems of teeth ma~ be removed previously or subsequently by means of a suitable operation.
In the case shown in Fig. 4 the location where said materi-- al is removed~ for example turned of~ determines the tangential align~ent of the rotor relative to the stator.
This method then has the advantage that it is comparatively sirnple to change this alignment during series production by selecting a different setting of the machine tool used, for ex.ample a lathe. An alternative is to start from a rotor construction as shown in Fig. 2, but without the nelical grooves defining the teeth~ and to form these grooves in all four systems of teeth in one operation.
The invention is not limited to the embodiment shown. In addition to the hybrid stepping 35 motor shown, the inventive princip e is also applicable to a reluctance stepping motor of similar construction as the hybrid stepping motor shown, i.e. to any motor with a~ially spaced annular and ro-tation-symmetrical systems of teeth.
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A stepping motor having a stator which at least comprises a first annular stator section with an annular coil and a magnetically conductive enclosure surrounding said annular coil, which enclosure terminates in a first and a second annular system of teeth, a second annular stator section with an annular coil and a magnetically conductive enclosure surrounding said annular coil, which enclosure terminates in a third and a fourth annular system of teeth, and a rotor with a toothing which cooperates with the first, second, third and fourth system of teeth, characterized in that the teeth of the systems of stator teeth are disposed axially in line and that the teeth of the rotor toothing are formed by the circumference of the rotor in that helical grooves are formed in the rotor surface.
2. A stepping motor as claimed in Claim 1, characterized in that the teeth of the rotor toothing are smaller in respect of their axial height than those of the systems of stator teeth cooperating therewith and that the teeth of the systems of stator teeth axially overlap the rotor teeth which cooperate therewith in both directions.
3. A stepping motor as claimed in Claim 2, characterized in that there is provided a first, second, third and fourth system of rotor teeth, which cooperate with the first, the second, the third and the fourth system of stator teeth respectively, which systems of rotor teeth are formed in that in addition to said helical grooves there are also formed circular grooves, 3.3.1980 PHN 9492 which axially bound the said systems of rotor teeth.
4. A stepping motor as claimed in Claim 1, characterized in that the teeth of the systems of stator teeth in respect of the axial height are smaller than those of the rotor teeth cooperating therewith and that the teeth of the rotor toothing axially overlap the coopera-ting teeth of the systems of stator teeth in both direc-tions.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL7904817A NL7904817A (en) | 1979-06-20 | 1979-06-20 | STEPPER MOTOR. |
| NL7904817 | 1979-06-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1135759A true CA1135759A (en) | 1982-11-16 |
Family
ID=19833389
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000354170A Expired CA1135759A (en) | 1979-06-20 | 1980-06-17 | Stepping motor with permanent magnet in the stator and rotor teeth arranged helically |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5610070A (en) |
| CA (1) | CA1135759A (en) |
| CH (1) | CH651706A5 (en) |
| DE (1) | DE3022433A1 (en) |
| FR (1) | FR2459575A1 (en) |
| GB (1) | GB2052175B (en) |
| NL (1) | NL7904817A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3935682A1 (en) * | 1989-10-26 | 1991-05-02 | Messerschmitt Boelkow Blohm | ELECTRIC DRIVE MOTOR, ESPECIALLY FOR CONTROL AND CONTROL PURPOSES |
| FR2689700B1 (en) * | 1992-04-03 | 2004-12-03 | Commerce Internal Echanges Tec | Advanced rotating electric machine. |
| JP3071392B2 (en) * | 1996-04-22 | 2000-07-31 | 多摩川精機株式会社 | Hybrid type step motor |
| JPH09285099A (en) * | 1996-04-05 | 1997-10-31 | Tamagawa Seiki Co Ltd | Hybrid type stepping motor |
| DE102006027819A1 (en) * | 2006-06-16 | 2007-12-20 | Siemens Ag | Ring coil motor |
| FR3018966A1 (en) | 2014-03-21 | 2015-09-25 | Mmt Sa | HYBRID ELECTRIC MACHINE |
| WO2016110966A1 (en) * | 2015-01-07 | 2016-07-14 | 株式会社ゲネシス・ラボ | Motor |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DD76727A (en) * | ||||
| US3441819A (en) * | 1966-04-18 | 1969-04-29 | Superior Electric Co | Reciprocating linear motor |
| DE2249729A1 (en) * | 1972-10-11 | 1974-04-25 | Binder Magnete | STEPPER MOTOR |
| DD101521A1 (en) * | 1972-12-21 | 1973-11-12 | ||
| FR2348595A1 (en) * | 1976-04-15 | 1977-11-10 | Anvar | ROTATING-LINEAR HYBRID MOTOR |
| DE2727450A1 (en) * | 1976-07-05 | 1978-01-12 | Philips Nv | SYNCHRONOUS MOTOR |
| JPS5729945A (en) * | 1980-07-30 | 1982-02-18 | Toshiba Corp | Analytical apparatus for total organic carbon |
-
1979
- 1979-06-20 NL NL7904817A patent/NL7904817A/en not_active Application Discontinuation
-
1980
- 1980-06-14 DE DE19803022433 patent/DE3022433A1/en active Granted
- 1980-06-16 FR FR8013324A patent/FR2459575A1/en active Granted
- 1980-06-17 GB GB8019754A patent/GB2052175B/en not_active Expired
- 1980-06-17 CH CH466380A patent/CH651706A5/en not_active IP Right Cessation
- 1980-06-17 CA CA000354170A patent/CA1135759A/en not_active Expired
- 1980-06-18 JP JP8156780A patent/JPS5610070A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE3022433A1 (en) | 1981-01-29 |
| GB2052175B (en) | 1983-04-07 |
| FR2459575A1 (en) | 1981-01-09 |
| FR2459575B1 (en) | 1983-10-28 |
| JPS5610070A (en) | 1981-02-02 |
| CH651706A5 (en) | 1985-09-30 |
| DE3022433C2 (en) | 1988-12-08 |
| GB2052175A (en) | 1981-01-21 |
| NL7904817A (en) | 1980-12-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |