DE2416695A1 - Self-starting synchronous and stepping motor - has permanent magnet rotor with grouped stator poles and has specified angles between poles - Google Patents

Abstract

The self-staring synchronous and stepping motor has coaxially or radially excited stator poles for m phases and a common permanently-magnetic rotor. The stator poles for each phase are brought together into u groups of alternate polarity. (The pole groups for each separate phase alternate in passing around the air-gap). The stator poles are excited centrally or individually. The numbers of stator and rotor poles are different. The angle tp between adjacent stator poles within one pole group of one phase is equal to the angle between adjacent rotor poles. The angle between poles of different phases is equal to tp (1+1/m).

Description

Synchronous motor or stepper motor The invention relates to a self-running motor Synchronous motor or stepper motor with permanent magnet rotor, in particular of the claw pole type, in which the number of stator and rotor poles do not match.

Motors of this type are known as low-speed multi-pole motors of the Homopolar type with combined stator poles z. B. according to DB Pat. 1488654 for a long time Known time.

The disadvantages of these motors are also known. So is, for example, the utilization factor of the effective pole face at the working air gap only about = 50%. The manufacturing costs, especially for small power types, are very large and associated with winding difficulties.

The purpose of the invention is to provide low-speed synchronous and stepper motors manufacture which, in addition to good performance, also have a cheap industrial one Enable production.

The improvement of such a motor shall be shown in comparison with a two-phase synchronous motor based on our own DB patent, which has been tried and tested for 18 years No. 1021943.

The motor according to the cited earlier patent consists of two stators with central coils, the stator pole ring gears (4/5) and (40/50) of which mesh with one another, that a three-dimensional rotating field, based on the common claw pole rotor (11), is created.

Each of the two stator pole ring gears has the same number of poles like the common rotor, consequently the rotor poles are doubled on the circumference Number of stator poles opposite. The number of poles 2p of the motor is therefore given Rotor diameter and rotor tooth width zr limited for manufacturing reasons, because the stator tooth width zs can be made at most = 0.6 x zr. Another The disadvantage is that the magnetic flux ßr generated by the rotor is simultaneous can close p times over both stator pole ring gears.

To facilitate manufacture and the properties of such In order to improve the engine, another structure of the engine was developed according to the invention.

In known small synchronous motors and in the motor according to patent 1021943 is the ratio of the number of stator poles to the rotor poles in general Vz = 2. In the new engine, the ratio Vz is reduced to 0.8 on average. In order to the stator poles can be greatly widened or with the same mechanical stator pole width and the same rotor diameter, the pole pairs of the rotor are enlarged accordingly. With the latter measure, operated as a synchronous motor at the same frequency, Reduce the speed accordingly, used as a stepper motor, the step angle Reduce by two and a half to three times and at the same time reduce the maximum step frequency increase significantly.

The engine principle according to the invention is based on an example for a motor with 16 stator pole teeth and 2p = 20 rotor poles is shown.

In contrast to the arrangement according to Pat. 1488654, which always has poles of stator 1 with the poles of stator 2 alternate, is in the invention Motor usually at least one north and one south pole of a pole ring gear to one Pole group combined. The stator pole pitch tp is equal to the rotor pole pitch Vr. The poles of neighboring pole groups have different phases in the two-phase Execution usually a distance of 1.5 tp. With this arrangement, provided that each pole group consists of a = 2 stator teeth, in the case of a two-phase design Manufacture motors with p = 5 n rotor pole pairs, where n is an integer> 1 got to.

In the case of a motor according to Pat. 1488654, for example, one needs for a motor with 2p = 20 rotor poles, a total of 40 narrow stator pole teeth. For the new motor, as you can see, only a total of 16 stator pole teeth that are at least twice as wide, which are of course easier to manufacture and more stable in the production process.

With the usual 90 ° phase shift of the excitation currents in the stator Stl and St2 show the position of the rotor and stator poles in each excitation phase an almost ideal magnetic attraction or repulsion behavior.

The development patterns showed that the running behavior and the torque has been significantly improved. In the example shown, Fig. 1 and Fig. 3, with a Rotor 2p = 20 each phase has u = 4 pole groups with two stator poles each.

The stator pole groups 3, 5, 7 and 9 or 4, 6, 8 and 10 belong to the corresponding stator pole wreaths Fig. 3a (phase 1) and Fig. 3b (phase 2). There according to the motor structure according to the invention (Fig. 1) for every second pole group of the the polarity sequence must change in the same phase, an embossed stamped part is 11 and 12, for the inner and outer pole ring gear of the two stator pole ring gears, accordingly Figures 2a and 2b are required. The angles between the pole teeth must therefore o (= 2p + u. 1800 and ~ 2p - u. 1800 p.u p u.

Outer pole ring gear (12), inner pole ring gear (11), coil core (13) and Excitation coil (14) put together result in a stator pole ring gear, Fig. 3a to 3b.

The two stator pole rims 3a and 3b are together with the common Rotor in the usual way in a cylindrical housing (15) made of non-ferromagnetic Material, e.g. aluminum, corresponding to the pole tooth arrangement, Fig. 1, accommodated.

If the motor is to be used as a stepper motor, the Depending on the type of control, stator coils are known as single or bifilar wound Double coils (center tap) are carried out.

The invention can also be applied to larger motors with wound stator poles use. Such a motor, FIG. 4, is required for a rotor, for example with 2pr = 10 poles and a = 2 a total of 8 stator poles made of layered stator sheets. In contrast to a known embodiment, the stator pole spacings are according to the invention p are not the same, but alternately amount to 1.5 to.

In this way, larger motor types can be made with a single stator core getting produced. The correct pole sequence can be achieved by means of the appropriate winding connection or winding direction can be achieved. The engine properties are also essential here better than the known embodiment with the same pole spacings, in which partially negative tensile torques and thus pulsating torques and unequal step angles appear. If you make u = 4 and a = 1, then 2pr = 12. You then get again a motor with eight stator poles, FIG. 6.

The version with wound stator poles can be used with the appropriate Use a modification of the pole arrangement for three or more phases.

The angle between the individual stator pole groups must then 36 = rpr (1 + 1 / m. The general condition for a multiphase according to the invention Synchronous and stepper motor is as follows: Number of rotor poles: 2pr = m u (a + b + l / m) Number of stator poles: ps = mua This gives, for example, for a three-phase motor, Fig. 6, with m = 3; u = 1; a = 3 poles per pole group and b = 0 one rotor pole number 2pr = 10 and one Number of stator poles ps = 9, with the stator winding per pole group in a known manner all poles can be distributed or applied to a part of the poles.

Should a motor according to the invention be connected to two phases of a three-phase network are connected, then it is appropriate to use a two-phase motor, e.g. B. after Fig. 3 or 4, with a corresponding modification of the pole group displacement angle, Fig. 7 to use. In this case t = Z1 2 = 3tp = 3 # r = 540 ° / pr.

In order to keep the engine running smoothly, it is necessary to use the Make angle t p (1 + 2/3) ° U. # 2 = # p (1 + 1/3) 0.

A stator lamination section similar to FIG. 7 is also for a capacitorless one Single-phase synchronous or stepper motor with a clear direction of rotation suitable if the two phase windings 14/1 and 14/2 connected directly to the power source and one of the two stator windings has an additional short-circuit winding (16), Fig. 8, is obtained. This winding can consist of a single ring or one more or less short-circuited multi-wire winding.

In order to get the engine running smoothly, it is well known Condition for a circular rotating field of the Polversatzwinkelrl to choose so that the spatial Pole offset angle (p) p and the electrical phase shift angle given by i and i2 # complement each other to 180 °.

The examination of the development patterns has shown that engines after the present invention has considerable advantages in terms of manufacturing technology bring and have significantly improved electro-mechanical operating properties. With the given equations, the number of motors according to the invention can be determined Predetermine the rotor and stator poles exactly.

Claims (14)

Claims 1) Self-starting synchronous and stepper motor with more than four coaxially or radially excited stator poles for m phases and common permanent magnet rotor, characterized in that the stator poles per phase form u groups of alternating polarity are summarized, the pole groups of the individual phases along the working air gap alternate, the stator poles are excited centrally or individually, the number of stator and rotor poles do not match, the pole pitch angle between the stator poles within the pole group of a phase equal to the rotor pole pitch angle Lr and us the angular distance between the poles of different phases is made r = 'Cp (1 + l / m) will. 2) self-starting synchronous and stepping motor according to claim 1, characterized characterized in that the rotor (2) alternating north and south poles on its circumference has the same pole pitch. 3) Self-starting synchronous and stepping motor according to claim 1 and 2, characterized in that the rotor preferably consists of a non-magnetic shaft and one or more axially magnetized permanent magnets (17) with two or more toothed pole pieces (18) made of soft magnetic material, in particular pure iron, consists. 4) Self-starting synchronous and stepper motor according to claim 1 to 3, characterized in that the pole groups are the same size and at least in total m x 1 pole groups are available. 5) Self-starting synchronous and stepper motor according to claim 1 to 3, characterized in that the pole groups are of different sizes and overall at least m x 2 pole groups are available. 6) Self-starting synchronous and stepper motor according to claim 1 to 4, characterized in that with two poles per pole group, the pole offset angle Fig. 2a, b 0t = 3600 / u + (a-1) 180 / p and n = 3600 / u - (a-1) 180 / p. 7) Self-starting synchronous and stepper motor according to claim 1 to 4, Fig. 2a, b, characterized in that with a single pole of each pole group Pole offset angle between the stator poles of the same polarity of a stator olZ 3 = 3600 / u. 8) Self-starting synchronous and stepper motor according to claim 1 to 7, characterized in that the number of rotor poles 2pr of the general equation 2pr = mu (a + b + l / m) and the maximum number of stator poles of the equation p5 = mua is sufficient and Pr> 3. 9) Self-starting synchronous and stepping motor according to claim 1 to 8, characterized in that the number of poles per pole group a is an integer > = 1 and b = 0 or <= 1. 10) Self-starting synchronous and stepper motor according to claim 1 to 9, characterized in that each phase winding consists of two symmetrical winding halves consists and all beginnings and ends of the winding halves for the power connection to To be available. 11) Self-starting synchronous and stepper motor according to claim 1 to 10, characterized in that all north and south poles of a phase by one coaxial central coil (14), Fig. 3, are excited. 12) Self-starting synchronous and stepping motor according to claim 1 to 10, characterized in that in the case of a radial single pole arrangement according to FIG. 4, at least one pole per pole group has an excitation winding 14 / m. 13) Self-starting synchronous and stepper motor according to claim 1 to 12, characterized in that for special applications, Fig. 7, the sum of Pole group offset angle # 1 + # 2 = 2 # r (1 + 1/2) and the ratio # 2 / # 1 = 2 or 1/2 is done. 14) Self-starting synchronous and stepper motor according to claim 1 to 12, characterized in that all pole groups together with a clear direction of rotation are excited, part of it a copper load to split the stator Magnetilusses (16), Fig. 8, and the pole group offset angle # 1 from from the phase shift depends on the two winding currents il and i2.