DE3049191A1 - ELECTRIC STEPPER MOTOR AND COMBINATION OF MOTOR REDUCER USING IT - Google Patents

Description

JAEGER P 1143

30A9191

- 5 DESCRIPTION

The invention relates to an electric stepping motor and a combination of motor and reduction gear using it .

A well-known stepper motor, such as that used for driving odometers in the dashboard of Cars is used, comprises a permanent magnet designed rotor, which is rotationally symmetrical about its axis of rotation has lying outer circumference, over which at regular angular intervals, which correspond to a step, alternately positive and negative poles are arranged, and a stator arranged around the outer periphery of the rotor the same number in in the same way has spaced poles, these being carried by a winding which is either in the axial Extension of the rotor or around the outer circumference of the same, optionally a magnetization can be communicated which is opposite to the magnetization of the two immediately adjacent poles of the stator, and the polarities of all of the poles of the stator can be reversed at will, so as to gradually reverse them To achieve rotation of the rotor.

This type of motor would be extremely satisfactory if its plat- /. Required, be it in the direction of the axis, if the coil is arranged next to the rotor in this direction, be it in diameter, if the coil is around the rotor is arranged around, does not always cause difficulties in accommodating it in the dashboard of a vehicle would lead.

In so far as the space requirement of the engine is direct

is linked to its number of poles or this number cannot be significantly reduced, appears The desirable reduction in the footprint of the motor is difficult when considering this well-known concept of a stepper motor maintains.

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The object of the invention is therefore to reduce the space required by stepper motors to facilitate their installation, in general as a unit with gearbox, for example in the dashboard of a vehicle, and for this purpose to propose a new type of construction of an electric stepper motor.

To solve this problem, the invention proposes to design the rotor as a ring that extends in the radial direction Has magnetized zones whose sense of magnetization alternates and which are at an angular distance of one step and distribute poles of the stator along the inner circumference and along the outer circumference of the ring at the same time, where the angular distance between two adjacent poles of the stator in the circumferential direction, i.e. from two adjacent ones inner or of two adjacent outer poles, is equal to twice the step and each inner or outer pole faces an outer or inner pole with an intermediate ring of the rotor.

Means is provided for optionally having one and the same polarity in those within the rotor ring generated stator poles and one and the same polarity with the opposite sense in the other poles of the stator can be, wherein a stable position of the rotor with respect to the stator is a position in which the rotor in Reference to an inner and an outer stator pole, which occupy the same radial position, a region of its Inner circumference with the current polarity of the observed Inner poles dos stator reverse polarity and a range of its outer circumference with the polarity of the considered outer pole, i.e. with that of the inner pole of the stator same polarity. According to the distribution of the different poles, the magnetized areas of the rotor, which are adjacent to the areas thus lying, then free, i.e. in a radial position between the radial positions of neighboring in the circumferential direction

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Stator poles.

Reversing the polarities of the poles of the stator, which leads to / that each of them comes in front of an area of the rotor with the same polarity, rotates the rotor by one step in order to restore equilibrium, whereby the direction of rotation is determined by a corresponding decision-making structure of the poles of the stator.

It should be noted that with such a structure according to the invention, each magnetized region of the rotor of two radially adjacent elementary poles with opposite permanent polarity is formed. If you have a Comparison with a conventional concept motor having the structure described above, and considering the elementary poles of the rotor in the case of the motor with the structure according to the invention, they occupy one and the same Number of rotor poles with respect to an equal total number of poles of the stator at a given moment an angular position which, for a number of poles of the stator along the outer circumference of the rotor or along the inner circumference of the rotor in the case of the motor according to the invention »half the number of along the outer circumference of the rotor distributed poles in the case of a motor of conventional design.

Such an arrangement is advantageous in that it increases the total volume of the engine the diameter of the permanent magnet making up the rotor, i.e. that generated by this motor Increase torque because this torque is substantially proportional to the square of the radius of the magnet. In other words, with the same torque, it is possible to change the diameter of the magnet, i.e. the space required of the motor to reduce, it should also be noted that it is also possible to reduce the angular extent to increase the Sta borpole and its radial space requirements

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JAEGER - - -Γ - ■ · ..- ·. P 1143

The stator of the motor is 1, which is 3 with respect to an axis of the stator rotatable rotor with 2 and a planetary reduction gear moved by the rotor during its rotation denoted by 4. This planetary gear 4 has the task, for example, of two sets of counter rollers 7 and 8, of which the first a total odometer and the second a partial odometer, both known types and therefore not described here in detail (see in particular FIG. 1), represents about their axes parallel to the axis 3 5 or 6 to turn.

In the example shown, the rotor 2 is formed by a disk centered on the axis 3 and oriented transversely to it 9 and an annular ring 10 is formed which forms an angled outer edge of this disc. In the direction of axis 3 and in the sense of a distance therefrom, the ring rim 10 is delimited by an inner circumference 11 and an outer circumference 12, both of which are rotationally cylindrical around the axis 3.

With its central area, the disk 9 is free about the axis 3 rotatably mounted, including the disc, fixedly connected to it, a central sleeve 13, generally with a rotary structure with respect to the axis 3 and with a central cylindrical bore 4 for rotation about this axis 3. The hole 14 lies around the edge 15 of a shaft 16, which is also rotationally cylindrical around the axis 3, and which engages with the stator one of its transverse ends, designated 17 in FIG. 1 and located in the interior of the annular ring 10, is firmly connected. The sleeve 13 is flush with the surface of the disc 9 from which the ring rim 10 protrudes, and in turn protrudes from the second surface of the disc into an area where it has a spur toothing 18 on the outside, with which it engages in the circumferential toothing of a satellite pinion 19 which is free about an axis 20 parallel to the axis 3 is rotatably mounted on a satellite carrier 21, which in turn is freely rotatable about this axis 3. At her that

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to diminish.

Furthermore, the structure of the motor according to the invention allows better utilization of the rotor forming the rotor Permanent magnets, because this magnet is magnetized in the direction of its thickness, which maximizes the magnetic circuit closes in a manner which is extremely beneficial for high coercivity magnets, such as those in general Plastoferrite selected for this application. For example, allowed in the case of an application an odometer for a car the connection of a motor with a structure according to the invention and a planetary gear the production of a particularly compact motor-coaster unit with sufficient gear reduction with a reduced number of gears.

According to a preferred embodiment of the engine According to the invention, the inner and outer poles of the stator are optionally magnetized by a common winding, which are located inside the inner poles of the stator, i.e. inside the rotor, around the axis is what allows a clever use of the interior of the rotor and avoids an outer coil, whereby Once again, the space requirement outside the motor or the motor-coaster combination that uses it is essential is decreased.

An embodiment of the invention is described below in connection with the accompanying drawing. On this shows:

Fig. 1 in axial section a combination motor-reduction gear according to the invention, as it is for driving the total and partial odometer at a Vehicle is used;

FIG. 2 shows a section along plane II-II of FIG. 1; 3 is a view of an outer pole of the stator as it appears in a centripetal direction, and FIG 4 schematically shows the electrical voltage supply for the winding of the stator.

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HUNTER ; . P 1143

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End 17 facing away transverse end 23 carries the shaft, a fixed one Plug 22, which fixes the satellite carrier 21 against an axial displacement against the sleeve 13, which in turn against the fixed core 24 rests, which, as will become clear further below, forms the central part of the stator 1 and that The end 17 of the shaft 16 is firmly connected to it.

The one hand with the teeth 18 of the sleeve 13 in the Engaging satellite pinion 19 is on the other hand with a fixed ring gear 25 which has the axis 3 as the axis and which engages along its rotationally cylindrical about the axis 3 The inner edge is equipped with a fixed seat 26, which also firmly receives the stator 1 on the inside.

In this way, a rotation of the rotor 2 about the axis 3 causes a rotation of the satellite carrier 21 about the same axis 3 in the same sense, but at a lower speed. The satellite carrier 21 in turn carries an external toothing 27 which mesh in a manner known per se with external toothing lying around the axis 5 and 6, which on the Rolls 7 and 8, which form the odometer, are seated.

According to the invention, as can be seen in detail from FIG., The one for permanent magnetization Suitable material existing rotor 2 in the area of the ring ring 10 in regular alternation an even number of zones that have permanent magnetization in the radial direction in one sense or the other.

In the example shown, the ring rim 10 ', 2.B. five zones, such as 28, which have an elementary south pole labeled S in the immediate vicinity of the outer edge 12 and represent an elementary north pole, denoted by N, in the immediate vicinity of the inner edge 11, with such zones alternate with zones such as 29, which have a north pole labeled N in the immediate vicinity of the outer edge 12 and a represent the south pole designated by S in the immediate vicinity of the inner edge 11, the two elementary poles N and S which determine such a zone 28 and 29, respectively in the

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JAEGER ■. - -. P 1143

are oriented in the same radial direction with respect to the axis 3. The angular distance that a zone 28 from the immediate adjacent zones 29 or in each case the zones 29 separating from the immediately adjacent zones 28 is equal to Angular length of the step of the motor, i.e. equal to the angular path of the rotor with respect to the stator for each of its rotations about the axis 3 in a predetermined sense, which is indicated in FIGS. 2 and 3 by an arrow 30.

In the example shown, a 360 ° rotation of the rotor around axis 3 corresponds to ten steps, because the total number of intervals between a zone 28 and a zone 29 is equal to 10, of course, according to the invention but also produce stepper motors whose rotor contains a different number of magnetized zones 28 and 29, provided that this number is an even number, so that the necessary alternation of zones with opposite in the radial direction Magnesia, such as 28 and 29, is taken into account. The number of these magnetized zones corresponds to the number of Steps for a rotation of the rotor by 360 ° around its axis with respect to the stator.

Complementary to this, the stator has 1 poles whose Polarity is reversed to cause the rotor to rotate gradually.

According to the invention, these poles of the stator are distributed simultaneously along the inner circumference 11 and along the outer circumference 12 of the ring ring 10, their total number being equal to the total number of magnetized zones 28 and 29 of the ring ring 10 or possibly one
is an even sub-multiple of this number. Half of these poles of the stator are arranged along the outer circumference 12 of the ring ring 10, the other half along the inner circumference 11, in both cases regularly, with each pole arranged on the outside of the ring ring having a pole arranged on the inside of the same in the same Radial direction is assigned.

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JAEGER - '- ·' P 1143

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Thus, in the example of FIG. 2, five poles of the stator, such as 31, are along an imaginary ring with the axis 3 dem Inner edge 11 of the annular ring 10 of the rotor is arranged facing and five further poles 32 along an imaginary ring with the axis 3 facing the outer edge 12 of the annular ring 10 arranged, wherein a pole 31 is assigned to a pole 32 in the same central radial direction and the middle Orientations of two adjacent poles 31 or two adjacent poles 32 angularly by the value of two steps are offset.

In the example shown, each of the poles 31 is formed by a finger which is oriented essentially parallel to the axis 3 and which is fixed on the edge of a pole piece 33 in the form of a disk centered on the axis 3 and perpendicular to it in the immediate vicinity of the disk 9, from which the ring collar 10 protrudes,:.:;:. Zz. —.Jx ~ zz £ lz £ .zzz SXte i = r Λώί J is: i: e Sci ^ zi «= 33 firmly connected to the above-mentioned core 24, which has the shape of a socket, which is in the sense a distance with respect to the disk 9 of the rotor continues and in its area furthest from this has a fixed disk 34 which is centered on the axis 3 and oriented transversely to it, this disk 34 engaging over the free edge 35 of the annular ring 10 and has on its edge beyond the ring collar, which are arranged facing the circumference 12 thereof and each of which forms a pole 32. The fingers forming the poles 31 and 32, the pole shoes in the form of the disks 33 and 34 and the core 24 are made of a magnetic material with as little hysteresis as possible. In the annular space which is delimited around the core 24 by the disks 33 and 34 and by the imaginary ring along which the poles 31 are distributed, at least one winding 36 is arranged, which is connected to an external supply circuit 39 (see FIG. 4 ) is connected by conductor 37, which the disc 34 in an opening 38 of the-

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enforce the same.

The role of the winding 36 and its supply circuit 39 is to induce magnetization at a given point of time one and the same polarity in all of the poles 31 and a magnetization of opposite polarity thereto in the entirety of the poles 32 so as to rotate the rotor 2 by one step in the direction of the arrow 30, and then reverse the respective polarities of poles 31 and 32 as desired, if necessary is to cause a renewed rotation of the rotor 2 by one step in the direction of the arrow 30.

For this purpose, the winding 36 can be a single winding in which an electrical alternating current is in one or the other the other direction is generated to effect the successive incremental rotations. One is shown Another embodiment in which the winding 36 is in two windings, 36a and 36b, in opposite directions of winding disintegrates, these having a common terminal 0 and a separate terminal A or B.

The supply circuit 39 comprises complementary terminals O ¹ , A ¹ , B'i which are connected to the terminals 0, A, B, respectively.

The circuit 39, which can be implemented without difficulty by the person skilled in the art, is selected so that it responds to the receipt of successive control pulses which, in the case of the example shown, come from a sensor 40 which counts the revolutions of the output shaft of the drive gear (not shown) , alternately on its output terminal A *, to the terminal A and the winding 36a, and its terminal B ¹ , to the terminal B and the winding 36b, emits an electric current of the same polarity, which, depending on whether it passes through the winding 36a or the winding 36b runs, causing the fingers 31 and 32 to polarize in one direction or the other.

In FIG. 4 there are two simultaneous diagrams 41

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and 42 shows the time course of the electrical signal at terminal A ¹ and that of the electrical signal at terminal B ¹ , as they are output when the circuit receives successive pulses coming from circuit 40.

It can be seen in this figure that a square wave signal corresponding to the input of a current into one of the terminals, A or B, of coil 36 as a result of the circuit receiving a control pulse from circuit 40 39 corresponds, a time follows and precedes during which no current is applied to this terminal and for the during of part of the same the other terminal a current on receipt of the immediately preceding impulse or the immediate following pulse of the sensor 4 0_ by the circuit 39 receives.

The time during which a signal is given to one or the other of the terminals A and B, denoted by T .. and T_ in FIG. 4, for example, corresponds to one rotation of the rotor 2 in the direction of the arrow 30 to a step due to the fact that the application of the winding 36 in each case at the poles 31 and the poles 32 causes the occurrence of identical polarities to those of the immediately adjacent elementary poles of the rotor, which at each of the poles 31 and 32 a repulsion of these elementary poles and the attraction causes immediately adjacent elementary poles, the rotation stops when the latter are opposite the poles of the stator. The intermediate _{times T 3} and T., at which no signal is given to terminal A or B, correspond to times when the engine is at a standstill.

In Fig. 2, the motor is shown at the beginning of a rotation time, such as T ₁ or T_, where the poles 31 have a south pole, the elementary south poles of the inner circumference 11 of the ring rim 10 and the pole 32 a north pole, the elementary north poles of the outer circumference 12 of the ring rim 10 face upside down.

So that the consecutive to the terminals A and B

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JAEGER 'P 1143

3 043131

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given currents each time a rotation of the rotor 2 in the same predetermined sense / that indicated by the arrow 30 in the Fig. 2 and 3 is indicated, effect, one can provide a wide variety of known solutions and, for example each pole 31 or 32 of the stator into a main pole and an auxiliary pole, the one indicated by the arrow 30 Direction sits immediately in front of the main pole, subdivide, with the main pole having a greater mass than the auxiliary pole, so that when the rotor is stopped with respect to the stator, the mean radial position of the rotor poles in the sense of the arrow 30 of the intended direction of rotation slightly with respect to the mean radial direction of the corresponding Stator pole is shifted (as this__Fig. 2 shows where the Rotor at the very beginning of its one step rotation

occupies this position). ~ - ^

Fig. 3 shows two embodiments of the separation of a Poles 32 into a main pole and an auxiliary pole, the individual poles 31 being separated in the same way.

A first embodiment of the separation, the dashed is shown, consists in a division of the finger forming the pole into a downstream finger 32a and a finer 32b, wöbe that runs upwards, immediately in front of it the finger 32a has a greater mass than the finger 32b and represents the main pole and the auxiliary pole through the finger 32b is formed.

Another embodiment of the separation is shown in solid lines. According to this embodiment, the projection formed by the then sole finger 32 with respect to the disk 34 of the stator increases progressively from the upstream to the downstream area, so that first the auxiliary pole and then the main pole results, which can be emphasized by the fact that one in the downstream region abruptly increases aj_ _e height of the finger 32, as shown.

Other embodiments are of course contemplated

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without leaving the invention.

In general, the invention may take various modifications of the embodiments described and illustrated above be realized. In particular, the electrical control circuit is used for each application, such as 39, and choose the type of execution of the winding 36 in the most suitable manner, as well as the number of poles that as a function of the desired torque and the desired number of steps per revolution of the rotor and as a function of the constraints imposed by the space requirements.

It should be noted that an inventively implemented Stepper motor, especially in the embodiment described as an example, may be insensitive to certain circumstances occurring external magnetic fields and in turn no magnetic interference field despite the feeding of its winding with pulses to the outside because the surrounding stator plays the role of a shield.

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Claims (9)

Electric stepper motor and motor-reduction gear combination using it Priority: December 26, 1979 - FRANCE - No. 79 31 673 PATENT CLAIMS 10 1.) Electric stepper motor with a stator and a Rotor "; which are rotatable relative to each other about an axis, characterized in that the rotor (2) has an even number of areas (28, 29) which are in regular Angular distances are arranged along a ring (10) rotating about the axis, each of these areas being closed two analogous neighboring areas (29/28) at an angular distance of one step and a permanent magnetization in a radial direction and in the opposite sense to that of the adjacent areas, 130044/0575 JAEGER P 114 3 jf << * ¹ ■ .v-'ifC.IiC.v-iTJ - 2 - that the stator (1) has the same number of poles or a number of poles that one is an even sub-multiple of this number, has, these being present in two sets of half the number of stator poles each, which are regularly arranged along the inner circumference or the outer circumference of the ring are distributed and in each case a pole of one SaL ^ tü a pole of the other Set radially opposite; and that means for optionally establishing one and the same polarity in the poles of one set and one and the same polarity in the opposite sense in the poles of the other sentence and for the optional reversal of this Polarities of the two sets is provided so as to rotate the rotor with respect to the stator by one Bring about step. 2. Motor according to claim 1, characterized in that the device is at least one of the All of the poles of the stator (1) common winding (36) inside the ring (10) and a core (24) running along the axis of the winding inside the same is arranged and has two pole pieces arranged transversely to the axis (3) on both sides of the winding, wherein the pole pieces each along the inner circumference and the outer circumference of the ring carry fingers (31, 32) which substantially or approximately parallel to the axis and each of which has a pole of one or the other Set of poles of the stator. 3. Motor according to claim 2, characterized in that the winding (36) is a single one Winding is and that a device is provided with the optional in this single winding an electrical Current of a certain polarity can be generated alternately with one or the other direction of flow. 130044/0575 HUNTER ... . .... P 1 14 3 ■ ^: "'" ^: " ^: - ■ ··""- 3043131 4. Motor according to claim 3, characterized in that g e k e η η, that the winding (36) has two windings (36a, 36b) in opposite directions and that a device for the optional generation of a current of the same polarity alternately in the one winding or the other winding is provided. 5. Motor according to one of the preceding claims, characterized in that each pole of the Stator (1) a main pole and an auxiliary pole, which is in the direction of rotation of the rotor directly upstream with respect to the main pole angeorö is net and has a lower mass than the main pole, includes. _15 ~ 6. Motor "according to claim 5 and one of claims 2 to 4, characterized in that the main pole and the auxiliary pole through in the direction of rotation of the rotor downstream and upstream regions of a single finger are formed, the mass of which increases downstream. 20th 7. Motor according to claim 5 and one of claims 2 to 4, characterized in that the The main pole and the auxiliary pole are formed by two adjacent separate fingers (32a, 32b), namely by one finger located downstream in the direction of rotation of the rotor and one finger located upstream in the direction of rotation of the rotor, which has a lower mass than the finger lying downstream. 8. Combination motor-reduction gear, characterized in that it is a motor according to one of the preceding claims, the rotor (2) has an output shaft (14) on which a freely rotatable Satellite carrier (21) is attached, which carries a planetary gear with the axis (3) parallel axis, the one- 130044/0575 HUNTER . P 1143 on the one hand with an external toothing (18) of the output shaft of the rotor and on the other hand with an internal toothing (25) of a ring in engagement, the axis of which coincides with that of the rotor.
5 9. Odometer, characterized in that that it has a combination motor-reduction gear according to claim 8, that the satellite carrier (21) has an external toothing (27), the axis of which coincides with the axis (3) of the rotor (2) and which coincides with a complementary toothing of a counter roller is in engagement, and that the device for optional manufacture and reversing the polarity of poles of the stator (1) is controlled by pulses that control the rotation of the output shaft of the travel gear. 130044/0575