DE2943529A1 - Timepiece drive motor with permanent magnet rotor - is formed by ring with alternating polarity sectors and soft-iron plate facing stator - Google Patents

Abstract

The motor has a permanent magnetic rotor (10) and a stator (12) having an energising winding coupled to an AC source. The rotor (10) is in the form of a ring (14) with permanent magnetic sectors of alternating polarity giving a magnetic dipole moment parallel to its rotational axis. Pref. the side of this ring (14) facing the stator (12) has a soft-iron plate (16) which acts as a shunt for the magnetic flux. The hub (18) of the rotor is formed by a cylindrical element (18a) fitting through the aligned central holes in this plate (16) and the permanent magnet ring (14). The rotor shaft (20) projects beyond the hub (18) and fits into a socket in a mounting plate (22), its other end being enlarged and fitting into a recess at this end of the hub (18). The stator (12) pref. comprises an oval energising winding (24) and two soft-iron crescent-shaped pole shoes (26).

Description

Magnetic rotor motor The invention relates to a magnetic rotor motor with a rotatably mounted, multi-pole permanent magnet having rotor and with a stator having an alternating voltage-fed field winding.

Such magnetic rotor motors are known and are for example in the form of self-starting magnetic rotor motors as drive motors for clocks used. For example, in the work "Handbuch für Uhren", Vol. 3, Point 4.2, Fig. 42 212 d a self-starting synchronous motor with an asymmetrical permanent magnet Star rotor described whose tooth-like poles with magnetically soft pole pieces interact, which can be magnetized with the help of an alternating voltage-fed excitation winding are. From the same work (Fig. 42 212 b) there are also impressed magnetic rotors Poles or attached flat magnets known, which do not use Polleit bodies can be.

The disadvantage of the known magnetic rotor motors is that their rotor and / or their stator are constructed in a relatively complicated manner and that their degree of effectiveness often leaves something to be desired. In addition, there is often a considerable additional Effort necessary to achieve the asymmetries required for the self-start.

Based on the prior art, the invention is based on the object to specify an improved magnetic rotor motor that is very simply constructed, nevertheless has a good efficiency and also a continuous drive of the pointer mechanism delivers. It should also be possible to use the engine in an embodiment of the invention as a self-starting magnetic rotor motor.

This task is performed with a self-starting magnetic rotor motor of the initially described type according to the invention in that the runner has a Annular ring with permanent magnetic sectors with alternating opposite, has a magnetic dipole moment oriented parallel to the axis of rotation (A-A) and preferably a soft iron plate on its side facing away from the excitation winding for guiding the magnetic flux, and that the excitation winding is oval is.

The decisive advantage of the magnetic rotor motor according to the invention consists in the fact that he baptizes with his permanent magnet and the soft iron plate easier and cheaper to manufacture and that the stator has an excitation winding has, which is also inexpensive to manufacture and easily with a non-magnetic or non-magnetizable carrier plate, in particular connected to the board of a clock can be. When connecting the excitation winding to the substrate of an integrated Circuit of an electronic clock, it is also particularly advantageous that the Excitation winding and the soldered wire ends with the integrated circuit Form assembly unit thereby a cheap assembly and disassembly of the engine is made possible.

In an embodiment of the invention, it is also advantageous if the magnet rotor motor as a self-starting magnet rotor motor belonging to the stator Pole pieces formed and characterized in that the pole pieces about Are crescent-shaped and so asymmetrical at the ends of the excitation winding to the longitudinal axis of the same are arranged that each other in the area of the ends diametrically opposite the excitation winding with respect to the rotor, in plan view wedge-shaped air gaps result, starting from their widest point in Narrow the direction of rotation of the rotor.

Another favorable possibility with a magnetic rotor motor according to the invention to achieve a self-start is that as a pole piece and part of the stator a permanent magnet is provided, which the rotor in such a position specifies that when the excitation current is switched on, an optimal Starting torque is reached.

It has proven to be particularly advantageous if, in the case of a magnetic rotor motor according to the invention the rotor has a hub, which preferably made of plastic and made in one piece with the other elements of the runner or can be glued and the side facing away from the field winding at the same time forms a pinion for a clock drive.

In this embodiment, the rotor can be rotatably mounted on a shaft with a construction in which the one shaft end is preferred held in a rotationally fixed manner in a carrier plate, in particular in the front plate of a clock is, while the other end of the shaft forms a thickened head, which the rotor secures in the axial direction in its position.

Further details and advantages of the invention are provided below explained in more detail with reference to drawings and / or are the subject of subclaims. Show it; 1 shows a schematic longitudinal section through a preferred embodiment a magnetic rotor motor according to the invention.

FIG. 2 shows a cross section through the engine according to FIG. 1 along the line 2-2 in this figure; 3 shows schematic representations corresponding to FIG. 2 a-d of the motor according to FIGS. 1 and 2 for different rotor positions for explanation the motor function; 4 shows a schematic diagram for explaining the course of the torque .hk as a function of the rotor angle; Fig. 5 shows a strongly sgbematisiortes Circuit diagram for explanation a driver circuit for a magnetic rotor motor according to the invention and FIG. 6 are diagrams for explaining the course over time a - c essential tensions at. Operation of an engine according to the invention.

In detail, Fig. 1 shows a along the line 1-1 in FIG Longitudinal or axial section through a self-starting magnetic rotor motor according to FIG Invention, which has a rotatably mounted rotor or rotor 10 and one opposite has the rotor fixed stator 12. The rotor 10 has as the main element an annular permanent magnet 14 - or a circular disk-shaped Permaner.tmagneten 14 with central opening - which in the exemplary embodiment four in the circumferential direction with alternating polarity successive parallel to the rotor axis A-A has magnetized sel: torfömige partial magnets, their north poles in usual Way with N and whose south poles are denoted by S. With the stator 12 facing away Side of the permanent magnet 14, d. H. in Fig. 1 with the top of the permanent magnet 14, a soft iron plate 16 is connected, which is used as a shunt for guiding the magnetic flux is used.

The rotor 10 also has a hub 18 which is a cylindrical Part 18a has which rotatably in the> central opening of the plate 16 and of the permanent magnet 14 is used. Adjacent to the Alittel opening is the Hub 18 is also provided with a circumferential annular flange 18b to which outside or above, a further section of the hub 18 is connected, which is shown below is designated as pinion 18c.

A shaft 20 is provided for the rotatable mounting of the rotor 10, one end of which rotatably in an eye of a carrier plate 22 used is and at the other - in Fig. 1 lower end - a reinforced head 20a is provided is that the rotor 10 in the axial direction in its position with respect to the carrier plate 22 secures, the carrier plate 22 when using the rotor according to the invention in a clock mechanism, for example, the front plate of a clock can be.

-'ie hub 18 thus simultaneously forms a bearing for the rotor 10 and a pinion for a gear train to be driven by the motor according to the invention (not shown).

The stator of the motor according to the invention consists of an oval excitation winding 24 and us two pole pieces made of soft iron 26. The shape of the excitation winding 24 and the pole pieces 26 is particularly clear from FIG. You can see that the Pole pieces 26 are essentially crescent-shaped and that the field winding 24 bounded an elongated, rounded at the ends central opening 28, at the Ends the pole pieces 26 are arranged in such a way that between the projection of the circumference of the rotor 10 in the plane of the pole pieces 26 and the inner edge 26a of the pole pieces 26 result in wedge-shaped gaps 3C, which arise in the exemplary embodiment Widen in the circumferential direction of the rotor 10 counterclockwise, the wedge-shaped Column 30 run mirror-symmetrically to the piercing point of the axis A of the rotor 10. The one gap 30 is thus obtained by mirroring the other gap on the rotor axis A-A.

Finally, the stator 12 is overall with respect to the rotor axis A-A centered and connected to a support plate 32, which in practice for example a circuit board of a clock mechanism Oßer the substrate of an electronic circuit of a ohr can be. The desired height of the air gap s between the rotor 10 and the Stator 12 is in practice after attachment of the stator 12 carried out on the carrier plate 32 when the latter is attached to the carrier plate 22 is, w at the same time also the desired orientation of the stator 12 with respect to the rotor axis A-A is brought about.

After the above with reference to FIGS. 1 and 2, the expansion of an inventive Magnetic rotor motor has been described in detail, the function of this is now Motor based on Fig.

3a - 3d are explained in more detail. In these figures or in the sub-figures 3 are each the contours of the excitation winding 24 and the rotor 10 and des Permaner.tmagneten 14 indicated, in addition, the position of the permanent magnetic Sectors or the partial magnets of the permanent magnet 14 is indicated. Farther are for each of the sectors or partial magnets respectively the following sizes in the form of Vectors drawn: the so-called Laplace force F; the current I, the magnetic induction B.

If one looks first at Fig. 3a of the drawing, then in this figure the central axis of the sectors with the north pole facing the observer - in these Sectors, the magnetic field lines are directed upwards out of the plane of the drawing, which is indicated by the symbol "", while the magnetic field lines in nen south pole sectors run perpendicular to the plane of the drawing downwards, which is indicated by the Symbol "e" is indicated - opposite the longitudinal center axis B-B of the excitation winding 24 rotated clockwise by the angle γ 1.

This results in the following situation with regard to the torques: Ma1 + Na2 + Ma3 = Ma where Mai to Ma3 are the individual torques that add up to the drive torque Ma and where each of the moments 2F nxrn with the radii rn from the rotor axis AA to the point of application of the corresponding Laplace force Fn It can be seen that the torque Ma2 the torques Mai 1 and Ma3 is opposite, but a resultant drive torque Ma still remains, the size of which depends on the special position of the magnet pole surfaces in relation to the part of the excitation winding covered by the rotor; a position which is mainly caused by the pole pieces 26 in the starting phase, in which a position of the rotor which is symmetrical to the excitation winding, as would be the case for 1 = 0, is prevented due to the mutual magnetic effect between permanent magnetic poles and soft magnetic pole pieces and of the magnetic flux generated by the excitation windings, whereby an effect similar to that of the stepper motors developed by Lavet is achieved.

In the partial figure 3b, the central axis of the N-sectors is rotated with respect to the longitudinal axis of the exciter winding 24 by the angle γ - # / 4. At this angle of rotation of the rotor 10 with respect to the stator 12, the maximum drive torque Mmax 'results according to the following relationship; which results easily from the partial figure 3b, which clearly shows that the Laplace forces F in all front sectors act in the sense of a clockwise torque, with the radii r also being the same for all four forces F.

Correspondingly, the following relationships apply for an angle of rotation γ 3 = # / 2 according to FIG. 3c: Mc1 + Mc2 = Mc and for the angle of rotation γ = # / 2 + γ Fig. 3d the following relationships: Mdl + Md2 + M d3 = Md In the end, according to FIG. 4 of the drawing, an approximately sinusoidal curve of the torque A1 is achieved as a function of the angle of rotation γ, the torque M = f (γ rotor) changing between M = 0 and M = Mmax. The torque curve applies to the unloaded engine without friction losses.

Due to the inertia of the rotor of the magnetic rotor motor, the following also applies the following equation for the total output torque of the rotor: Mt = 1/2 Mmax A driver circuit has been used to supply the magnetic rotor motor according to the invention according to block 40 in rig. 5 proved to be advantageous, this block 40 with a Another block 50 is connected, which the the synchronization freeness generating crystal oscillator 52 with frequency divider and the associated logic Circuits 54, 56 - control logic 1 and 2 - for the control or synchronization the driver circuit 40 comprises. The crystal oscillator 52 with frequency divider and the Logic circuits 54, 56 ensure that the bipolar motor control pulses be synchronized with the clock or control frequency of, for example, 32 Hz, which is stabilized by the clock, which is obtained by dividing the crystal frequency down, thereby increasing a motor speed of 8 Hz is achieved.

In each case, the driver circuit 40 causes the rotating magnetic rel4 of the rotor 10 in the field winding 24 induced coil voltage UIND to control the changes in polarity of the current through the field winding 24, to which a capacitor C2 is connected in parallel, is exploited by alternately two transistors T1 and T3 or two transistors T2 and T4 are blocked. Of the The switching state of the transistors T2 and T3 is also determined by the switching state of the transistors T5 and T6, which are controlled by signals Q or # of the control circuit 54 and only put through the motor drive current when the signal O is a logic "1" or L and the transistors T5 and T6 are high impedance (Fig. 5). When the induction voltage passes through zero, it is applied to the collectors the transistors T1 and T4 connected capacitor C3 to a feedback pulse R m an input of the control circuit 56, whereupon a reset needle pulse with practically no delay RST from control circuit 56 - control logic 2 - to control circuit 54 - control logic 1 - is sent out and resets the signals O, Q so that the Driver circuit 40 for switching on the drive pulse of the next half-wave (Fig. 5, 6) is prepared. The switch-on point of the drive pulse is at the positive edge of the Q-Sicnal of the control logic 1, the switch-off takes place at the zero crossing the coil induction voltage, so that the duty cycle of the drive pulse is determined is determined by the load-dependent phase shift between the sinusoidal induction voltage and the square control pulse. A larger load on the rotor shaft leaves the induction voltage lag more and increase the duty cycle, the higher energy supplied maintains the engine speed despite the increased load. There is thus the possibility of using the Energy content of the drive pulses supplied to the motor as a function of the load to vary in such a way that the power consumption automatically adapts to the existing load is apprehended. The switching of the driving pulses is controlled by the induction voltage of the train controlled and is thus based on the most favorable position of the rotor on the drive train.

The starting behavior of the motor is controlled by one with the collectors the transistors T1 and T4 on the one hand and with the collectors of the transistors T5 and T6, on the other hand, connected vibration generating capacitor C1 and through an additional driver pulse S supplied via a transistor T7 is improved.

The control electronics also prevent the motor from switching off by a reset pulse if the run is too slow before the next reset pulse, if more than one crystal pulse has arrived since the previous reset pulse.

In practice, favorable results have been achieved with a rotor whose coil length in the direction of the axis B-B was only about 23 mm, while the Outside diameter of the rotor was about 10 mn. This motor, its current consumption in the unloaded state was 55iA and in the loaded state 100µA and the one Delivered output torque of 0.7 pN, worked at a speed of 8 Hz an efficiency of 26%, which is definitely cheaper for motors of the type under consideration value is.

FIG. 6a shows the driver circuit explained with reference to FIG the course of the induced coil voltage UIND (f '= 16 Hz), while FIG. 6b shows the Motor voltage U, Og (f = 16 Hz) shows. Finally, Fig. 6c shows that of the stake 50 delivered control pulse train, namely a square pulse train with a quartz stabilized Frequency of 32 Hz.

While above as a preferred embodiment of the invention a self-starting magnetic rotor motor with soft magnetic pole pieces in connection with its associated control system was explained in detail at this point it should be pointed out again that the underlying of the invention Principles also with a non-self-starting magnetic rotor motor without soft magnetic Pole pieces can be realized with advantage, with the electrical control of the engine described above can be kept unchanged can, while additionally suitable mechanical or electromechanical Auxiliary devices are provided to "start" the engine.

Furthermore, in an embodiment of the invention, there is the possibility to train a self-starting magnetic rotor motor in such a way that instead of of the soft magnetic pole pieces 26 a permanent magnet / 60 is provided, such as it is indicated by dashed lines in FIG. 2. With the help of such a permanent magnet 60 it is possible to hold the rotor 10 when coasting in a position in which when the excitation current for the excitation winding 24 is switched on again maximum starting torque so that the motor can start by itself. at the viewed Embodiment with a four-pole permanent magnet 14 this condition is fulfilled when the line on which the permanent magnet 60 and which intersects the axis of rotation A-A of the rotor lo, with the longitudinal axis B-B the excitation winding 24 an angle g of f- / 4 or an angle of 450 or a includes a slightly larger angle.

Claims (7)

Claims 0 Magnetic rotor motor with a rotatably mounted, multi-pole permanent magnets having rotor and with an alternating voltage fed Stator having excitation winding, characterized in that the rotor has a Annular ring (14) with permanent magnetic sectors with alternating opposing, has a magnetic dipole moment oriented parallel to the axis of rotation (A-A). 2. Motor according to claim 1, characterized in that on the Excitation winding (24) facing away from the rotor (10) a soft iron plate (16) is provided for guiding the magnetic flux and that the excitation winding (24) is oval is trained. 3. Motor according to claim 1 or 2 with one for the purpose of self-starting stator having soft magnetic pole pieces, characterized in that the Pole pieces (26) are approximately crescent-shaped and at the ends of the excitation winding are arranged so asymmetrically to the longitudinal axis of the same that each other in the area of the ends of the excitation winding diametrically opposite with respect to the rotor, in the plan view wedge-shaped air gaps (30), which are based on their narrow the widest point in the direction of the direction of rotation of the rotor (10). 4. Motor according to claim 1 or 2 with one for the purpose of self-starting at least one stator having a pole piece, characterized, that the pole piece is designed as a permanent magnet (60) and with respect to the field winding (24) is arranged in such a position that the rotor (10) when not fed Excitation winding (24) can be set in the position in which the maximum Drive torque results. 5. Motor according to claim 4, with a four-pole permanent magnet having rotor, characterized in that the permanent magnet serving as a pole piece (60) on an axis of rotation (A-A) of the rotor (10) intersecting and with the longitudinal axis (B-B) of the excitation winding (24) arranged at an angle of 450 inclusive line is. 6 gate according to one of claims 1 to 5, characterized in that the rotor (10) has a hub (18) which is the rotatable mounting of the rotor (10) is used and has a portion (18c) designed as a pinion 7. Motor after Claim t, thereby. marked that -the hub with the elements of the rotor (10) is integrally connected