DE1763078A1 - Harmonic drive for a digital stepper motor - Google Patents

Description

Dr. O. DITTMANN DA-961

K. L SHIP
Dr. A. v. FiINER

Patent Attorneys B β a c h r e i b u n_g

ϊΐίϊΐϊ "* ¹⁵ the" F ^ ffESiTaR

of the company

MESUR-MATIC ELECTRONICS CORPORATION, Warner, New Hampshire 03278, USA

concerning

Harmonious drive for a digital stepper motor

Priorities No. 627,410, March 31, 1967, USA. No. 664,331, Aug. 30, 1967, USA,

Brief description

The invention includes a digital stepper motor a u »a wave rotating swashplate for generation a formal contact between two groups of assigned teeth under the influence of an electromagnet! - f see stepper. The swashplate is with the Shaft around which it rotates connected by a universal joint, which can move axially freely, but is held radially in its position relative to the shaft.

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Execution see description

.Bekennte facilities z \ mi hiv /.- uicniachi-m Antr.. "Ei" or Üpannungs vellengetriebe received their Bezßiolmung because of an operation example in the areas of plant formschiüssigen swisohen the serrations of two sprockets übet- the Unifau _f * in the form of a sinusoidal or substantially sinusoidal wave are propagated, which is characteristic of a wave-shaped deflection or deformation wave in one of the toothings. The principle of a harmonic drive results in detail from US Pat a rigid circular ring gear, a flexible ring gear from here to different diameters are -jedoch provided in coaxial arrangement with the rigid ring gear and a Auaführungsform deformation transmission means _r through which the flexible ring gear is driven and simultaneously bent out of his teeth with the teeth rigid ring gear at several circumferentially spaced points in engagement, which are separated by areas in between without contact, in this way a rotary drive of the flexible ring gear by the deformation transmission device results in a port planting a deformation wave around the circumference of the flexible ring gear in connection with a relative rotation between the two sprockets.

According to the US patent mentioned above, the gear rim is provided with internal teeth, i.e. teeth, weloiie extend radially over the inner circumference. The flexible teeth

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BATH ORIGINAL

or deformation toothing is also designed as a toothed ring and arranged within the rigid ring gear. This flexible ring gear consists of thin elastic material, which is elastically deformable and provided with an external toothing which starts from the radial outer circumference. The pitch circle diameter both serrations differ as a result of the Difference in the number of teeth between the serrations, where the deformable ring gear in accordance with the determined deformation of the deformable ring gear by the Deformation transmission device when the gear rims interlock there are fewer teeth than the rigid gear rim has, according to the number of digits one positive engagement between the teeth or a Multiples of this. This arrangement means that at any given point in time a large percentage of the teeth of both are more cooperating Teeth in engagement over $ 50 each Perforation.

As can be seen from the USA ^ patent mentioned above, the deformation transmitter is attached to a shaft, with the deformable teeth and the rigid ring gear coaxially and is designed in such a way that forces are exerted on the inner circumference of the deformable ring gear, if the deformation transducer is in a position within the deformable ring gear was brought / to deform the deformable ring gear and the desired form-fitting Engagement between the two sets of teeth on a plurality of Spaces distributed over the circumference

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au achieve. If the deformation transmitter is thus one Is subject to rotation, the deformable ring gear is driven in such a way that the teeth of the two teeth wreaths are only fully engaged at a limited portion of each point of the form fit and on each side each of these limited sections of full engagement have varying degrees of engagement, a complete mutual There is separation in areas that are approximately in the middle between the points of full form-fitting engagement, if there is sufficient disparity between the pitch circle diameters (and differences in the number of teeth) of the serrations. Accordingly, a deformation wave is propagated around the circumference of the deformable ring gear, one complete revolution of this ring gear corresponding to a tooth movement which is equal to the difference in teeth between the gear rims, and the gear rims are subjected to a relative rotation in which mentioned USA patent is explained that the deformation The transformer does not have to be the drive element, but that rather, each of the three elements (rigid gear rim, deformable gear rim or deformation transmitter) is the driving force Element and any of the other two elements can be the driven element. The ring gear with the largest Number of teeth per radian moves in the same direction as the deformation over + rager if the latter is the driving element.

Among other modifications of the deformation transmitter or

Wave generator according to the aforementioned US patent are two

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Electromagnetic execution forms provided, one of which is designed for a multi-phase and the other for a single-phase application. The USA patent specification 3,169 contains an arrangement in which the mechanical deformation transmitter or a wave generator cam, its bearing and an associated shaft are omitted and an electromagnetic drive system with a stator and a rotor are used instead . The rotor according to US Patent 3,169,201 βehrift comprises a plurality of thin planar magnetic per- meable M plates of substantially non-existent coercive force, can soft radial to the common axis of the drive shaft and the warnings in this axis intersecting planes against ■ corresponding linear points next to the surface of the defor- *. matable teeth (also referred to as "spiral spring") run away from the ring gear (also referred to as "circular spring") and, by virtue of their arrangement, can be pivoted against the surface when a magnetizing force is applied. The stator comprises an even number of evenly spaced solenoid pairs (with Magnet · ™ cores), which are provided in a circular arrangement coaxially to the arrangement of the rotor plates and are spaced apart from parts of the plates that protrude from the flexspline are. A progressive radial deformation of the spiral spring to generate a form-fitting singular interlocking between the two springs (teeth) at a number of points is achieved by switching in a corresponding number

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achieved by magnetic coils in the desired sequence, the magnetic plates being deflected in succession (by deformation of the armature) against the inner surface of the flexible spring, which causes deformation wave engagement of the springs. as in U.S. Patent 2,906 H 3. In US Patent 3,169,201 this generator is described for electromagnetic waves as an actuating device for a digital stepping motor, wherein diametrically opposite pairs of Solenoidwiclclungen W control circuit described are turned subsequential by a likewise, to a radial deformation of the flexural spring into an elliptical shape with a generate progressive deformation wave deflection over the circumference in discrete steps su.

US Pat. No. 3,169,202 describes other types of electromagnetic actuating elements for deformation shaft teeth or harmonic drives, which have a continuously rotating field and differ from one another primarily with regard to the axis of the armature. The basic structure, through which the Deformationewellenauslenkung is propagated is, however, quite similar to that of the two above-discussed United States patents, the armature according to the US Patent 3 ¹ 69 202 comprise an endless chain of magnetically permeable rigid members next to each other rotatably articulated members, wherein the chain is arranged adjacent to the surface of the spiral springs away from the ring gear; also a laminated core, the laminations of which are in successive plates along the axis of the actuators

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device and coaxially with it, run, with the scope successive slats by equiangularly spaced arranged slots next to the end face of the spiral spring is interrupted and the slots are provided with magnetic powder; and finally a coiled, magnetically permeable flat strip next to the inner surface of the spiral spring. In the case of each of these types of anchors, it is continuously rotating, through the corresponding one The application of energy to an associated stator produces an effective field to deform the corresponding armature, wherein the spiral spring is subjected to the deflection forces.

According to a proposal that does not belong to the state of the art becomes the basic concept of the electromagnetic swashplate motor together with a sequential circuit of the Stator winding used to achieve the desired step rotation of a swashplate or swashplate rotor. According to In this proposal, a pair of cooperating circular ring gears of the same diameter are provided, with the teeth protrude from opposing planes. At least one of the ring gears is rigid and on the inner surface of a wall of greater diameter of a concentric, one Double cylinder wall having housing attached that has a web connecting the walls at a common end, surrounded by a casing with an annular To create space. This casing or this housing contains a laminated magnetic toroidal core with several angular

distance located, wound bobbins according to the

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desired number of motor phases. A wave runs inside the inner wall of the housing length its axis and is rotatably arranged in bearings at each end of the front. the Inner wall enclosed space are kept. An armature or rotor in the form of a magnetically permeable circular plate is on the shaft is held rotatably with this and has its periphery adjacent to a flat surface of the plate, the second of the aforementioned sprockets, with one sprocket (preferably that on the armature) at least one tooth less than the other ring gear and teeth of the two serrations are usually spaced apart. In a preferred embodiment, the anchor is rigid as it is Ring gear. One end of the magnetic core in the housing faces the armature. When the phases (field windings) of the motor are switched on in the desired switching cycle, there is a successive attraction of the armature against each excited Winding. The teeth of the two ring gears are accordingly brought into positive engagement, so that they are with one another are only in engagement in a certain area of each ring gear at a given point in time. When the circuit As the coil advances, the armature wobbles around the shaft, the position at which the ring gear with the stationary one attached to the housing. The ring gear meshes sinusoidally along the ring gear according to the wobbling motion propagates. This represents a substantially sinusoidal wave motion, the armature forming a mass that is connected to rotates extremely low speed, which is due to the tooth difference,

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the number of motor phases and the stop sequence for the phases depends / There is a relative rotation between the two sprockets. If the anchor has the lower number of teeth, it rotates by this number of fewer teeth during each revolution of the wobbling process (i.e. each revolution of the engaged part of the ring gears) as well as in a Reverse direction to the direction of rotation of the tumbling action.

Be a second pair of sprockets is also provided by which of the anchors is coupled to the shaft, in accordance with to drive the armature rotation in such a way that the shaft makes a discrete (graduated) rotary movement according to the phase excitation of the Motors through the switching sequence. This second pair of ring gears transmits a torque to the shaft in positive and reliably with a minimum of sliding friction or energy loss due to wear. In the harmonious Drive system according to which does not belong to the state of the art Proposal are the teeth of the cooperating gear rings on only part of the overall ring in engagement, so that a total or partial form fit between only a small number of teeth occurs at any given moment. Thus the load or force on the shaft is actual not balanced, resulting in a condition which is somewhat disadvantageous in comparison with harmonic drive systems is state of the art.

The drive device constructed in accordance with the above-mentioned proposal, which does not belong to the state of the art, has however also various advantages over known facilities,

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which overall predominate significantly. For example, the deformation transmitter does not need to be supplied with any force an actual incremental rotation is not desired. In contrast to this, known devices require feeding a force to the deformation transducer to deform the spiral spring even when the device is in one state is located in which no rotary movement takes place, but only a state in preparation for a rotary movement. Over a Longer periods of continuous operation, this can result in a substantial energy saving in favor of the facility State-of-the-art effect on goal.

It also turned out that the institutions according to the state of the art, the spiral springs vibrate in a number of different frequencies, making for a smooth and effective Operation is disadvantageous. This disadvantage occurs with a drive device that does not belong to the state of the art Proposal is not one because la, unlike known deformation teeth, does not have a thin, elastic tubular spiral spring structure is present.

Swashplate motors are known per se with regard to the principle. In the proposal, which does not belong to the state of the art, however, the principle of the wide wobble plate or wobble teeth is also included two pairs of meshing serrations combined, with one serration each pair is attached to a swash plate made of magnetically permeable material and the other teeth of a pair through Attachment is attached to the case, while the other

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Teeth of the other pair in driving relationship with the shaft stands, whereby a drive or excitation circuit is provided through which the motor windings are switched on in succession to achieve the graduated rotation which the rotor performs a rotating tumbling process.

In only one of the above-mentioned electromechanical wobble plate actuation devices belonging to the prior art, there is an arrangement using at least two pairs of teeth, one teeth of each pair on the wobble plate and the other teeth of each pair on a frame member -or- are attached to a shaft "In this known" actuation device ", however, the wobble toothing, _t that blows the rotor, a web section made of a perme.nfint" ti magnetic material of high coercive force, - "which is radial with a center of a polarity and a The stator poles are arranged around the circumference of the frame with attached windings which, when energized, drive the coupled armature. A major problem is maintaining perfect interlocking contact between the rigid toothed surfaces. This usually requires the use of precise Construction dimensions by means of which all serrations are subdivided in order to achieve complete engagement between each pair of associated serrations. However, such a requirement entails high manufacturing costs and is to be rejected in terms of practical implementation. A

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Another requirement is that sufficient force be built up on the teeth to ensure that they are complete and steady Ensure engagement of the teeth when using the swashplate rotates. Although the desired form-fitting touch In a new set of serrations through the aforementioned accurate and expensive subdivisions of teeth can be made, nonetheless rerechlecken the serrations fast when subjected to continuous or long periods of operation. A related problem is maintaining the desired form-fitting contact Toothings assigned between the teeth despite wear, in particular an unevenness of the teeth with the original teeth. In the case of common swashplate clutch arrangements, there are errors in the associated teeth and wear of the teeth as the operation progresses accompanies a backlash, that is, an excessive and usually uneven distance between the teeth themselves, which is also transferred to links to which the teeth are attached, for example the drive or output shaft. This doorway causes a non-uniformity of the drebun of the toothing with intervals of acceleration and deceleration during each turning run, resulting in an intensified leads to uneven wear.

It is already the use of special biasing arrangements known, for example, the use of springs to press the Zahnun conditions and teeth together. However, if the spring force

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is too large, a significant amount of energy has to be used to overcome this force and the teeth in To bring intervention, whereby the efficiency is reduced. If the spring force is insufficient, the teeth lift applied load intermittently from each other at).

The purpose of the present invention is to provide a swash plate type stepper motor in which while maintaining the advantages according to the previously discussed, not for Prior art proposal, the coupling of the two φ Teeth sets are further improved. For this purpose the swash plate or swash plate is driven by a graduated magnetic field, to bring about a rotation on tracks, which are formed by the two sets of teeth. The coupling point in the form of a universal joint between the swash plate and the shaft on which the disk rotates is free to move longitudinally along the axis of rotation, however a sufficiently tight fit is maintained to allow radial movement of the coupling point during rotation to prevent. The force exerted by the drive magnetic field is in this way between the two sets of teeth divided that both sets are kept in full engagement at all times and unlike the facilities after the Prior art no game occurs.

Another purpose of the present invention is to provide a swashplate or swashplate stepper motor with an improved clutch compared to the state of the art

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arrangement, through which a perfect positive engagement between the serrations over the entire operation of the Motor is safely shared, even if it is a precise machining and there is no precise engagement of the sets of teeth and wear or irregularities in the wear of the teeth appear.

Another purpose of the invention is to create a swash plate stepper motor, in which the swash plate with a rotary ™ the shaft forming the axis is connected by a universal joint, which can move freely axially, but is held against a radial movement on the shaft.

Another purpose of the invention is to create a magnetohen Ratchet pawl in stepper motors of the type mentioned, by which the swashplate is held in contacting position without the need for articulated force.

fc The invention is explained in more detail below with reference to the drawings explained. Ss show:

Pig. 1 an embodiment of an inventive Stepper motor in front view as well as in the direction of view towards an armature end in a broken view,

Pig. Figure 2 is a section along line 2-2 of Pig. 1,

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Fig. 3 teeth of cooperating sprockets which are used in the engine of Pig. 1 and 2 contain bind, in a perspective partial representation,

Fig. 4 shows a Doppeletator arrangement in a stepping motor of the general type shown in Fig. 1, in section,

Flg. 5 shows a radial Sta door arrangement in an end view, FIG. 6 is a section along the line 6-6 of FIG. 5, A. FIG

7 and 8 show a voniagnetized stator structure for Formation of a flexible pawl in a digital stepper motor.

SIn the ring-shaped housing 10 comprises according to FIGS. 1 and 2 a pair of coaxial cylindrical walls 12, 13, which at a common end 15 by an end wall 17 with each other connected sjud. The housing 10 is made of suitable nonmagnetic material and is partially enclosed and open took one of field windings 20 and a magnetic core 21 Stator part 25 of a Dlgltalstufenotors determined.

The core 21 preferably comprises a strip of magnetic permeable sheet metal that is wound in successive layers in a ring or toroidal shape. The core is preferably im

Understand the angular distance between the slides 30,

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to accommodate field windings 20 on successive Lamellae of the magnetic sheet a, of which the core is made. The field winding end connections or field winding leads are expedient by the housing at one or more (not shown) points led out to establish a connection with a (not shown) power source. A winding or phase power supply circuit works preferably according to the stepper drive principle, and other power supplies can also be used.

Hollow surfaces 32 of the magnetic core 21 are at a small angle 33 », for example 1 °, relative to that perpendicular to the core axis running plane processed for a purpose to be explained below.

A shaft 35 runs along the axis of that described so far Motor and is held in bearings 37, 38 at the closed and open ends of the housing 10. The shaft has a section 39 of enlarged diameter or suitable gradations in order to ensure a fixation between the bearings without axial play with the latter option being preferred when both axial and radial loads are accommodated should. On the shaft 35 at a point next to the bearing 38 is a ring gear 40 on the shaft 35 by splinting or in other way attached, which is hereinafter referred to as the inner ring gear to avoid confusion with other ring gears to avoid larger diameters. The ring gear 40 follows the rotation of the shaft or vice versa.

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A rotor or armature 43, which in the present case represents a rigid circular plate made of magnetically permeable material, is also seated on the shaft. A bearing sleeve 45 is provided within a central passage in the rotor 43 in order to counteract the latter to support a bearing 46 comprising a small ball member 47. The ball member 47 has an axial bore of sufficient diameter to provide a relatively tight fit around the shaft, however slidably take up so that the rotor rotates against it can. Thus, the rotor or armature 43 can rotate against ^ be subject to the shaft, and the rotor 43. can in a little Assume a locking position running at an angle to the shaft. A retaining ring 48 is pressed onto the shaft 35 to prevent the rotor from lifting too far. The central bore in the ball member 47 allows the entire ball or Universal joint is axially movable on the shaft to to include any play that occurs when combing the teeth as Result of wear or an unevenness of the Teeth could occur, for example, and prevents any substantial radial movement of the ball joint. Accordingly, the Swash or rotor plate 43 able to move freely axially is, however, held radially.

The armature (i.e. the rotor or the swash plate) 43 iet provided with a pair of ring gears 49t 50 attached to or machined into a surface. These sprockets are opposite the poles 32 of the magnetic core 21, the ring gear 49 compared to the ring gear 40 with regard to

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netter and number or type of teeth and the intervention is hereby determined. The outer ring gear 50 is essentially the same on the underside of the rotor plate 43 next to its outer circumference and with respect to a stationary ring gear 52 Arranged diameter, which is provided on the inner surface of the free end of the cylinder wall 13 of the housing 10.

The relative positions of the various motor gears are such that opposing teeth on the cooperating Musseren sprockets 50, 52 as well as on the inner Ring gears 49, 40 only in a limited area of each respective pair of ring gears along a common one Sector from the axis of the overall structure at any given moment. The diameter of the outer cooperating sprockets 50, 52 are essentially the same, however, the number of teeth and thus their dimensions, different. In the exemplary embodiment shown, has the anchor crown 50 three hundred and fifty-nine teeth and dej? stationary ring gear 52 on three hundred and sixty teeth. Everyone who inner ring gear · 40, 49 perpendicular with, for example, sixty teeth provided, which «IIs extend at an angle of, for example, 30 ° with respect to a radial plane.

The housing 10 is closed by a hood 60 (FIG. 2) which, like the housing, is composed of non-magnetic material. The stator is preferably one-way Winding 20 and the core 21 in the housing 10 up to the height

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of the field windings or something above them encased using, for example, an epoxy resin. Although eight field windings (Phases) are shown, a large « Number of phases to be used.

In operation, the field windings are selected by a (not shown) switching or excitation circuit according to a certain sehalt sequence excited, for example A + B, B + C, C + D, D + E, Ef-P, F + (l, G + H, H + A etc., with the armature against the energized windings in the cited sequence is dressed »So comb the two external teeth 50, 52 along a sector area, which propagates with the "phase switching processes" that cause the armature disk 43 and shaft 35 to wobble. The small angle at which the pole faces compared to a are abraded perpendicular to the plane perpendicular to the shaft, enables a Tauael movement of this rotor without a disturbance between the limbs. Because of the changing number of teeth on the outer teeth 50 or 52 of the rotor or stator there is a relative rotation between these elements when the sector of mutual engagement moves one full revolution rotates, the helest over 360 of a "round tumbling motion" of the rotor. In the special case of the one mentioned above Number of teeth the armature (rotor) rotates by 1 °, what with coincides with one tooth for each 360 ° of the tumbling motion and in the reverse direction to the tumbling motion direction. If the number of teeth on the rotor toothing 50 is greater than that on the stator toothing 52, the relative rotation takes place in the same Direction like the tumbling motion.

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When the swash plate 43 rotates, the teeth of the internal serrations 40, 49 also mesh in a corresponding sector with respect to the serrations 50, 52, with the shaft 35 being driven. For the specified number of teeth, the shaft is subject to a rotary movement of 1 ° over a full tumble rotation. With eight field windings (phases), one tumble rotation requires eight phase reversals. Accordingly, each 360 ° rotation of the shaft requires a number of Bx 360 * 2880 steps or phase connections. A meshing of the two pairs of teeth in the above-mentioned manner is maintained without prejudice to slight errors or irregularities in the teeth in the two pairs of teeth, even if the teeth are worn during continued operation of the motor and, as a result, axial play of the ball joints and the swash plate occur . The field generated by the stator in accordance with the switching process produces a force which is divided between the two pairs of teeth and which produces a substantially uniform engagement pressure on the teeth of the sector corresponding to the actuated stator windings. The lack of radial movement of the ball-and-socket joint and thus of the swash plate also ensures precise rotation of the drive shaft 35 without backlash or play between the toothed rings.

Those in the aforementioned restricted sector (which, as will be understood, rotate with the phase switching operations The force exerted by the magnetic field, which arises from the excitation of the field windings, creates a lock (

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or striking the disk 43 trotζ the axial freedom of movement the ball joint connection. Therefore, a force mismatch arises with a strong downward-pointing, to the left side the plate 43 according to FIG. 2 exerted pressure, the diametrically opposite area of the plate for a special moment there is practically no force in the operation. The swash plate rotates around the ball-and-socket joint, which slightly is moved up on the shaft 35 so that the plate is locked. The resulting position of the ball joint connection along the shaft is self-aligning with respect to wear on the toothing and against irregularity of the toothing, as explained above.

In a modification of the embodiment described above the rotor 43 may be made of flexible material with enclosed rigid or powdered magnetic material and bent out into contact with the external teeth of the stator when the field windings are switched. The interacting surfaces of the serrations do not need to disappear with the teeth but can also be in the form of pens. Corrugations, ribs and the like be carried out, where only is required. that the surfaces have a friction-related system or a can cause corresponding contact. One of those, one Frictional elastic material can be in the form of natural or synthetic rubber for the interacting surfaces of the Serrations can be used, or as can be a surface made of rubber and the other be rigid, with frictional contact cuts, for example in the form of ribs, to achieve a

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Intervention are provided. In such cases, the angle of the rotor requires that the circumference of the contact surface of the Hotors somewhat larger than the circumference of the contacted surface of the Stator "teeth" is. The smaller the angle of the rotor inclination is, the greater is the ratio of the "tumbling revolutions" compared to the shaft rotation, as this can be done trigonometrically results.

The magnetic field that causes the rotor tumbling motion can φ by direct current excitation of separate phases or by a two- or three-phase alternating current excitation can be generated

Each of these variations, as in the preferred embodiment, produce extremely high reduction ratios high angular accuracy as well as simple construction and cheap components.

In the preferred embodiment described, the indications are to the only limited contact or contact area not necessarily to be understood as a single point of contact or there is a single point of contact. In many cases, the only area of contact may actually be over Extend a substantial expansion, but in contrast to the prior art, no multiple system areas are provided, which are separated from one another by areas in which the two teeth are at a substantial distance from one another. For example, if the cooperating surfaces of the serrations comprise rigid triangular teeth, the actual one occurs

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Contact between the two tooth surfaces on two at a distance located points at which the sides of the engaged teeth rest against each other, with between At these points the teeth are slightly raised from one another (Pig. 3). For practical reasons, however, the entire area is between these contact points represents the area of frictional contact or engagement, since a real engagement via the entire area is available.

The advantage of this cooperating Heibungsfläche comprises% in contrast to the prior art, according to which a flexible Keilnutenanordnung provided, the requirement of a low holding force, since there has to be overcome is no "spring action", further an improved transition (start / stop) -Ansprechvermögen because of the lack of this "spring action" in the drive, greater efficiency, an economical hex position and operation without slippage.

Fig. 4 shows a section through a double stator arrangement a stepping motor similar to FIG. 2, which otherwise corresponds essentially to that of FIGS. 1-3. The engine after Fig. 4 is therefore only described insofar as it is shown in its design differs significantly from the stepper motor described above.

The housing 110 consists of two interlocking parts 111, 112, which to each other in an expedient and customary manner can be attached, for example by a bracket or

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a tape and suitable fasteners (not shown). The housing part 111 corresponds practically in every respect to the housing according to FIGS. 1-3 with the exception that it has no exterior Fixed teeth corresponding to the teeth 52 of the preceding Described embodiment includes. The (swash plate (rotor or armature) 143 also has no external teeth «Instead is a stationary ring gear 114 cut lengthways. or on one Ring area 116 of the housing part 112 attached.

Matching teeth 118, 119 for the. stationary Zahnkram 114 and a ait a shaft keyed gear 140 are cut or in another way, for example by fixing _t on opposite sides of a swash plate 143 is provided. In this exemplary embodiment, the same number of teeth is provided on both the stationary gear crane 114 and on the swash plate teeth 118, while a tooth difference is provided for the teeth 119 and the gear 140 in accordance with the considerations mentioned above.

The swash plate 143 is connected to a shaft 135 by a ball joint 147 of the type previously described with the possibility of axial movement and radial fixing. Because the double stator type, with a swelter corresponding Stator part 127 is opposite to stator part 125 is, the shaft 135 is made longer than in the embodiment described above and rotatable in a bearing 130 as well as bearings 131, 132 held.

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In the operation of the double stator arrangement, a winding or adjacent windings of one of the stators (125 or 127) simultaneously with the excitation of a winding or diametrically thereto opposite windings on the other stator (127 or * 125) excited. Pur an eight-phase stator, for example the result - for the lower stator when considering Pig. 4th the switching sequence include 1 and 2 (this number refers to the winding / core Koaibinationen oösr phases), 2 and 3 »

3 and 4, 4 and 5 ....... 7 and 8, 8 and 1, etc. During respective time intervals over which the above M erwähn- occur th phase circuits, the upper stator is gemäse

of poles 5 and 6, 6 and 7, 7 and 8, 8 and 1, 3 and 4,

4 and 5 etc. excited. This assumes that the numbering the phases are identical for the two stators, that is, that the upper starter phase ifc 1 is directly opposite to the lower one Statorphaseφρί is etc. Pur is the reversal of the tumbling motion the phase of the switching sequence reversed. Accordingly, for example an upward force on the right side of the swash plate 143 as viewed by Pig. 4 exercised, while a downward force on the left side " the swash plate is exerted for a certain time, the plate, among other things, executing those "tracks" a wobbling movement that are given by the teeth. The double stator structure doubles the effective torque of the motor for a disk of the same dimensions, the speed of the Very responsiveness of the engine increases. Because the ball joint causes an axial movement and a radial limitation of the disk, both pairs of teeth are pressed into engagement ■ despite any inequalities or inequalities

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shapes that result from tooth failure or manufacturing tolerances.

Preferably the Taumelseheibenzahnung H8 and the locations of fixed teeth 1H triangular teeth which on at an angle ▼ 30 ° are cut and the ticket Benz clue 119 and the Vellenaahnrad 140 have triangular teeth on _r which at an angle of 45 ° are cut .. Since the Toothings 114, 118 have the same teeth awl, the disk or plate does not rotate, but only wobbles about the axis of the shaft on the traces formed by the serrations This reduces the yor-

Motor »lying moment of inertia while at the same time the ability of the Increased rotor for handling an external moment of inertia will. Bas gear 140 and thus the shaft 135 on which the Gear is misaligned or wedged, turns slowly, and either clockwise or counterclockwise to move the Axis as a function of the difference in the number of teeth between this toothing and the Taumeischeibenzahnung 119, if the disc 143 performs a tumbling motion.

By introducing a difference in the number of teeth between the disc teeth 118 and the housing reminder 116 and by maintaining it the number of teeth difference between the Seheibenzahnung 119 and the On the shaft gear 140, the ratio of the circumferential wobbling motion to the shaft rotation can be substantially increased or decreased as desired. For example, if the shaft gear 140 has ninety-one teeth and meshes with it

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reaching disc teeth 1.19 have ninety-two teeth, the shaft 135 rotates at a rate of one complete revolution for every ninety-one circumferential wobble the disc. If the disk teeth 118 ninety teeth and the housing toothing 116 eighty-nine teeth the disc rotates one full revolution In anticipation, i.e. in view of the phase changes, for each inclined tumbling movements all around. Under these conditions, the shaft 135 rotates in an opposite direction to the disk and makes a complete, one turn (opposite the housing) for 90 circumferential tumbling movements each. For two 90 ι I translation relationships in the same direction there is an overall transmission ratio from 45: 1.

From Pig. 1 and 2 it follows that the force on the swashplate, as it is exerted by the magnetic field, between the two Pairing of serrations is effective * Because their horizontal point is a Ball joint connection, which extends axially (in the longitudinal direction) can move freely along the shaft, but in the radial direction is held, there is a subdivision of the force between the two serrations in such a way that both pairs within the aforementioned limited sector can be kept engaged without any tendency to resolve. Thee cannot appear if the pivot point of the toothing is limited to a fixed point along the axis, in particular not if it is attached to the shaft, unless the teeth are preferred edited to achieve a precise intervention

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and subject to wear and tear over long periods of operation are «The problem of maintaining a tight engagement between the teeth is made more difficult by the presence of more than one pair or set of serrations and comes in handy in the absence of a "floating" pivot point according to , the present invention unsolvable.

Similar considerations also apply to the double stator arrangement according to FIG. 4

The use of springs or other elastic biasing elements Bur compensation of irregularities in one or multiple pairs of serrations is not completely effective and creates further problems. If the spring force is too high, to be overcome under normal engine driving force, which is the case when close engagement of at least one pair of serrations is contemplated, one results Decrease in motor efficiency as a result of the energy required to overcome the spring tension. Furthermore, this gives

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The presence of elastic pretensioning arrangements for the teeth, spontaneous vibrations and mechanical resonance or a "clink" during operation of the stepper motor.

A modification of the stator poles according to FIGS. 1 and 2 results from FIGS. 5 and 6. Instead of a circumferential arrangement of the poles on a common or substantially common core, the magnetic poles are arranged radially, with each group of north and south poles 190 and 191 being a special one

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Core and a particular winding is assigned, for example the components 194-195. This magnetic separation of neighboring poles makes it possible to produce a faster one Build up the magnetic lines of force with each phase connection.

line further modification of the stator poles results from Pig. 7, 8, according to which a Hagnetring 200 is ale base used for the stator core, said hing through zones in the veranschaulich- Mth manner iet permanently magnetized to provide alternating north and south poles au which old coincide the positions at which magnetically permeable pole pieces 202 are attached to the magnet ring. The field windings (e.g. 204, 205) are around the upstanding pole pieces corresponding to those according to Pig. 1.2 wrapped.

This arrangement provides a magnetic pawl to keep the permeable rotor (swashplate) in contact against the poles KU to which it is closest if a * Excitation of the phases ceases, since the force of attraction exerted on the rotor is inversely proportional to the square of the distance a of the pole to the rotor changes. Accordingly, the rotor can be held or locked to the motor without the need to deliver power be what for certain use cases, for example a tape feed, where the operation is intermittent stopped depending on the recording of information will.

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Claims (1)

Claims / 1./ Stepper motor with a pair of cooperating teeth, which are opposed to each other, usually in the distance projecting heating surfaces located in parallel planes or have serrations, electromagnetic components for a selective deflection of one of the serrations the other to create friction contact between the teeth in only a limited area of both .Zahnungen to one specific point in time, with the serrations of different dimensions for the friction surfaces, so that a continued Deflection of one tooth in contact with the other , Teeth accompanied by a relative movement of the pairs of teeth is characterized by a universal joint connection (47), which connects one (49) of the teeth with an axis of rotation (35) and an axial and rotary movement with respect to the Axis (35) allowing, however, a radial movement "is formed preventing. 2. Motor according to claim 1, characterized in that at least one (52) of the teeth is rigid. 3. Motor according to one of claims 1-2, characterized in that 'g e k e η η, that each the frictional contact of the teeth is caused by the attachment of the teeth, with different dimensions due to different numbers of teeth on the serrations are conditional. 109835/0493 4. Motor according to one of claims 1-3 »characterized geke η η - characterized in that the cooperating teeth (40, 49, 50, 52) are ring-shaped and lie on a common axis, the teeth from the normally uncurved, opposing one another Surfaces protrude so that the electromagnetic components comprise a magnetically permeable armature (43) coupled to the one toothing (49 »50) and electromagnetic actuating elements (20) are arranged in a circular arrangement around the common axis, each of the actuating elements being effective when excited, an electromagnetic% to produce netic field, thus on the coupled thereto a set of teeth (49 * 50) transmits the Auslenkungekräfte on the armature and. That the armature (43) comprises a rigid circular plate 5 · Motor according to claim 4, characterized in that d ss the Ringaahnung (49 _t 50) on a planar surface thereof ISTJ mounted adjacent the plate circumference that a shaft (35) along the axis and by the plate normally perpendicular to this ▼ runs, with the plate attached to the shaft through the universal joint (47) is held, about a relative rotation and a limited Allow angular orientation compared to the normally perpendicular arrangement. 109835/04 9 3 6. Motor according to one of claims 4-5, characterized by one extending along the axis of the armature (43) Shaft (35) »which rotates relative to the armature able to feed another pair of teeth (40, 49) whose one with the armature (43) and the other with the shaft (35) in cooperative relationship with one (50) of another Pair of teeth (50, 52) is coupled to rotate the Wave (35) as a function of the deflection and the resultant To generate rotation of the armature (43). 7. Motor according to claim 5 »characterized by * z egg without t, that the armature (43) responds to a successive excitation of the actuating elements (20) in a certain switching series in order to perform a tumbling movement around the shaft (35), an abutment comprising essentially a single point being established between the teeth (40, 49), and that a another pair of teeth (50, 52) is provided, which with the anchor (43) or. the shaft (35) is coupled to a Rotation of the shaft at low speed compared to the speed of the armature wobble to generate the shaft. 8. Motor according to one of claims 1-7 ,. characterized by at least one pair of cooperating, essentially flat teeth (40, 49) with mutually opposite, spaced heating surfaces, which are connected to the shaft (35) have a common axis, a wobble plate (43), which carries one of the pair of teeth, components (45-47), 109835/0493 which rotatably couple the swash plate with the shaft to an axial movement along the shaft and a rotary movement allow around the shaft, while the swashplate is radial opposite the shaft in the v / es released held iat, and structural elements (20) for selective pressing of the swashplate, to bring about a rotary movement on the coupling element, successive sections of the teeth in frictional contact to press against each other and a Helativdrehußg the teeth bring about. 9. Motor according to claim 8, characterized by Components for coupling at least one of the pair of teeth with the shaft (35) for generating a shaft rotation. 10. Motor close to claim 9, characterized g e k e η η ζ e i c h η e t, that the clutch components producing a rotation comprise a further pair of teeth, wherein the swash plate one of the other pair of serrations carries, and that structural elements are provided which the other of the further pair attached to the shaft by serrations. 11. Motor according to one of claims 8-10, characterized in that g e k e η η ζ ei ch η et that the swashplate is made of magnetically permeable. Material is made and the components are available for selection Pressing electromagnets include, which selectively excitable are to achieve a successive deflection of the swash plate about the rotary coupling element. 109835/0491 12. Motor according to claim 11, characterized s, Eke η η% (-. I η e t _t that the electromagnetic components a Pear of stators (125, "27) comprise, each multiple JCern / Wiclrlungs th Einhei (195) corresponding to the switching phase for the motor utafflOHt, the swash plate (143) being arranged between the S ^ atorpaar. 13 «Motor according to claim 12, characterized» that a further »pair of single acting teeth coaxially ία d · * provided on the pair of teeth ia \, the taueelplatte (143) one (118) of the« further pair of teeth on a surface opposite to that on which the one (119) of the aforementioned pair of teeth is attached, and that the pair of stators (125, 127) is arranged in the sense of a selective excitation to the swash plate for friction contact between diametrically opposite Ausjulenken parts of the corresponding serrations of the first-mentioned and further pair of serrations. 14. Motor according to claim 11s. characterized in that the electromagnetic component comprises a plurality of coils, each of which has a magnetically permeable core. 15, engine according to claim 11, characterized in that that the electromagnetic components have a stator with several core / winding units corresponding to the holding phases. for the motor, the stator eiren periaanent magnet * - · tiflierten section to form a magnetic pawl su, which receives the swash plate in the last Aualenkstteilung after the disappearance of the i'H ^ g ^ jff'U'ie ⁰¹³ excitation. 16. Motor according to claim 15, characterized in that the magnetic part comprises a member (200) which is attached to all stator plates (202) and permanently magnetized in successive zones of opposite polarity at corresponding attachment points of the cores .