DE1638237A1 - Electric motor with a mechanical brake that responds to a power failure - Google Patents

Description

Dipl.-Ing- Egon Prtnx # .- _Λ

Dr. Gertrud Hsusar I ^ -, jf | fj _s UjtJ »^ -

Snß. O-ii.'rEaii Quieter

Patent attorneys

8ÖC3 MUnchän - Pasing

Ern * beraer $ trass * 1 »

Gas II MOTEURS LEROY, Boulevard Marcelin Leroy, ANGOULEME / France

Electric motor with a mechanical brake that responds to a power failure

The invention relates to an electric motor

with a brake that responds to a power failure, ie which one the motor shaft is blocked by a mechanical brake when the stator is not fed.

There are already such engines with a

Brake disc known, which is rotatably connected to the rotor, can slide on the motor shaft and by Pedern against a fixed brake disc is printed.

The rotor carries a system which deflects part of the stator magnetic flux towards the sliding disk ₉

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that the lines of force are directed parallel to the axis of the motor Own component. Under these conditions, when the motor is energized, the brake disc will slide by the magnetic attraction away from the fixed brake disc and lies against the deflection system, which the roller an electromagnet plays.

In particular, it can be braked

Motor known in which the system for deflecting the stator flux is formed by a radially subdivided and attached to one of the side parts of the rotor rim.

This ring is opposite an extension of the stator and surrounds one of the short-circuit rings of the rotor. It is attached to the motor shaft by a thin hub that acts as a magnetic shunt.

When the stator is put under tension, the alternating flux sent into this ring can result from the radial slots of the same are not tangential. He can does not flow radially because it is deflected by the short-circuit ring, and because of its frequency it cannot flow through the magnetic Nebeiedflusa go. The river will therefore be parallel to the Axis directed to the brake disc, which is being attracted, and the structure of which allows the tangential flow of the river.

Such brakable motors work well

satisfactory when fed in three phases. With .iner Single-phase feed, however, these motors are not fimktionsflafcEgo In this case, namely, the brake disc is activated for each current half-wave attracted but when the magnetic flux ceases, its spring is pushed back. This creates vibrations of the Disk along the Hotorwelle, which with a real work of the brakable motor are incompatible. So it did not appear

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possible under these conditions with a ring to deflect the magnetic flux for the production of brakable motors To use single-phase supply.

However, the notifying party has found that the

Whirling ring can still be used to make a stable sturdy To achieve attraction of the brake disc even with single-phase feed, the means provided for this purpose also the Improve operating conditions with multi-phase supply.

The electric motor according to the invention, automatically braked in the event of a power failure, with a rotor ring, which diverts the magnetic flux of the stator to a brake disc, which slides on the motor shaft, is non-rotatably connected to the rotor and is elastically pressed against a fixed brake disc, the deflection ring made of magnetic metal by radial non-magnetic walls is divided into sectors, is characterized in that the Ablenkkranz has at least one shorted turn for the flow of the induced currents and two possible paths for the flow of the magnetic stator flux, of which the one outside this winding and the on the other (right by this runs.

Experience shows that both of them

The fluxes are out of phase with each other, so that a permanent pulling force on the moving brake disc in spite of the pulsation of the stator flux can be exercised with single-phase supply.

According to an advantageous embodiment

According to the invention, the deflection ring has a sequence of uniformly distributed short-circuit windings, each of which is separated by two successive Partitions made of a non-magnetic metal of the baffle and connected to these walls by two

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Rings is formed, one of which is on the inside of the baffle and the other on the outside of the same Brake disc is opposite.

The ring lying on the outside of the deflector rim is preferably parallel to the circumference of the rim located at a non-zero distance therefrom.

According to an interesting embodiment

of the invention, the inner ring is the one that holds the rods of the Cage armature of the rotor connects with each other, the partitions, the rings and the bars by filling the grooves of the Rotor, the radial slots of the deflector ring and circular formed in the inner surface and outer surface of the same Channels are connected by injection molding, these various cavities are in communication with each other. To this Thus, the rotor and the deflector ring can be firmly connected to one another in a single operation.

According to a further characteristic of the invention the outer ring of the short-circuit windings lies at such a small distance from the circumference of the ring that when starting and at Tollast the magnetic circuit running between the circumference of the ring and this ring is saturated, so that the largest Part of the deflected flux is out of phase with the stator flux.

The invention is explained below by way of example with reference to the drawing.

Fig. 1 is a longitudinal section of the brakable motor according to the invention.

FIG. 2 is a section along line H-II of FIG. 1.

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Pig * 5 is a view of the outside of the baffle alone _β

]? ig · 4 is a view of the inside of the Baffle.

Figure 5 is a section on line V-V of Pig. 4th

Pig. Figure 6 is a diagrammatic schematic showing, on a large scale, part of the sectioned baffle shows with breaking away of parts as well as the course of the magnetic fluxes and currents.

Pig · 7 is another diagrammatic part- | view of the rotor, with only the parts made of non-magnetic metal and the course of the rivers and streams is shown schematically.

Pig · 8 is a graph showing the change

the attraction forces in puncture of certain characteristic dimensions of the baffle.

In Pig. 1 and 2, 1 is the stator ring of a brakable motor, in whose slots 2 the field windings 3 are housed. In the example shown and according to One of the essential advantages of the invention can be the windings 3 both for single-phase feed and for three-phase feed are provided.

The stator ring 1 is fixed between two planar heights 4 and 5. The splash 4 directly carries a roller bearing 7 · The annular flange 5 receives a threaded side part 8 in which a roller bearing 9 is inserted irfc. The rotor shaft 11 is supported in the roller bearings 7 and 9. A rotor 12 in the form of a cage armature is pushed onto the shaft 11.

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The automatically operating brake has a fixed frustoconical brake disc 13 on which a Friction lining 14 is attached. The shaft 11 in turn carries the movable brake disc 15, which is mounted on the grooved part 16 can slide. The brake disk 15 carries on the side of the friction lining 14 a frustoconical side part 17, which should come into engagement with this covering. The side part 17 is moved in the direction of the pad 14 by a spring 18, which is coaxial with the shaft 11, on the one hand is accommodated in an annular groove 19 of the disc 15 and on the other hand on the side wall 21 of the rotor 12 facing the disk 15.

As provided for motors braked by a power failure without auxiliary winding, the length L _{0 of} the stator is slightly larger than the length L of the rotor. The annular space between the rotor 12 and the stator 1 is occupied by a Ablenkkranz 22 _f its special construction with the essential object of the invention is formed.

The ring 22 (Fig. 3 to 5) is formed by a solid ring made of a soft magnetic metal, whose axial bore 23 has a diameter which is considerable is larger than that of the shaft 11, so that there is no contact between the ring 22 and this skin.

The rim 22 is divided into adjacent sectors 24 by evenly distributed radial slots 25, which extend in the longitudinal direction down the outside 26 of the rim to its inside 27. The slots 25 extend radially up to the vicinity of the inner bore 23.

Furthermore, on the outside 26 according to a

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• An essential characteristic of the invention is an annular groove 28, which intersects all slots 25 'perpendicularly. The groove is at a relatively small distance from the circumference of the ring 22, which however is not zero.

On the inside of the ring 22 is a

other annular groove 29 is formed. The surface line of the tube 29 has an outline in the form of a broken line 31, the sections of which run obliquely to the shaft 11 in such a way that the sectors 24 of the ring 22 have a cross-section that tapers at their base. The bottom 32 of the hat 29 is straight, but has a similar annular groove 33, the purpose of which is explained below.

The groove 29 is arranged so that they

after the ring 22 has been placed on the rotor 12, approximately opposite the longitudinal grooves 34 provided for forming the cage anchor rods is located.

The wreath 22 is still noteworthy for that its width at the circumference is practically equal to the difference (L - L) between the stator length and the rotor length.

According to a preferred embodiment of the

Invention is placed against the surface 21 of the rotor 12, and a non-magnetic metal in the manufacture of the deflection ring 22 (e.g. aluminum) is injected under pressure into all spaces left between these two parts. The non-magnetic ones formed in this way metallic parts are shown in Fig. 7, in which the magnetic parts are thought to be removed, while in Fig. 6 the opposite is the case. These non-magnetic parts include the rotor bars 41, which are located on the side part 4 facing Side of the rotor by one also molded on

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Short-circuit ring 42 are combined. On the opposite On the side, the cast metal fills the annular groove 29, as a result of which the second short-circuit ring 43 is formed. This also forms the groove 33 metal fills a collar 44, which favors the anchoring of the deflector ring 22 on the rotor 12. The metal meets also the slots 25 and therefore forms radial walls 45 »which are united in the transverse direction by a ring 46, which corresponds to the part of the metal located in the courage 28. The ring 22 thus forms one piece with the rotor and is held firmly by the bandages, which are formed by the rings 43 and 46 connected to one another by the walls 45 will.

After casting the metal, the inner

Bore 23 of the ring 22 up to the tangential to the slots 25 Circle 30 enlarged (Pig. 3). Each sector 24 is then completely separated from its neighbor by the partitions made of non-magnetic metal, as in Pig. 2 is shown.

The through two consecutive parallel

The arrangement formed by the rings 43 and 46 united walls 45 forms a short-circuit turn or question turn, which is traversed by induced currents when the stator 1 is excited. The chosen training therefore allows in the deflector Form 22 short-circuit windings, which are shown schematically at S (Pig. 6) and distributed tangentially around the shaft 11 are.

Under these conditions, the of

the stator 1 in the deflection ring 22 induced flux P into two fluxes P ₁ and P ₂ . The flow F ₁ is the one which flows directly from the circumference of the ring 22 through the section 51 of the outer surface bounded by the ring 46 and the radial walls 45

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26 occurs. This flow directed parallel to the shaft 11 is in phase with the stator flux and causes the attraction of the brake disc 15

_{The second part F 2} induced in the ring 22

of the stator flux passes through the short-circuit windings defined above before exiting through the outer surface 26 between the central bore 30 and the ring 46. This flux is out of phase due to the short-circuit currents flowing in the short-circuit windings. It can therefore be seen that the attraction - exerted by the ring 22 on the movable brake disc 15 - does not cease when the stator supply current goes through zero, since the fluxes on the two sections of the surface 26 separated by the ring 46 do not go to zero at the same time will.

Furthermore, one notices that at the moment of

Starting and under load, a large part of the river F seeks to feed the non-phase-shifted circle F ... However, the partial flow F «passing through the short-circuit windings S offers the advantage of contributing to the rotation of the motor by supplying an additional torque. It is therefore expedient to favor the river F "over the river F _1. This result is achieved according to the invention in that the design is made in such a way that the part of the deflector ring 22 lying on the other side of the ring 46 (surface area S ₁ corresponding to the annular surfaces 51) is saturated during starting and at full load. This saturation aims to limit the size of the river F ^ in favor of the river F _2. In practice, the ratio of the surface S to the surface S of the side 26 is approximately between 10 and 20 feet, and particularly interesting results in the vicinity of 15 9 ^ can be obtained.

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Pig. 8 shows the changes in the tightening force

F as a function of the ratio S ₁ Zs expressed in $ . At A a ι

the holding force at standstill is shown at B, the holding force during rotation and at 0 the tightening force at standstill. the

Forces F are measured in kg. It shows that the holding power a

of the rotor rapidly decreases in accordance with the increase in S. but the tightening force increases with S ^. A wide group of experiments also showed that the distance between the two curves A and C increases simultaneously with the cross section of the ring 46. It is therefore advisable to reduce this ring in order to reduce the To increase the tightening force at standstill, but of course within the limits compatible with good mechanical strength.

The above description ultimately shows

that the position of the ring 46 relative to the circumference of the ring 22 plays an essential role. If this ring were formed on the edge of the rim so that the surface area of the sectors 51 becomes zero, a practically constant attractive force could not be obtained at standstill with single-phase current and the brake disk 15 would vibrate vigorously.

Furthermore, one finds the surprising result that even with three-phase power supply, the from the ring 22 attraction exerted on disk 15 increases. Indeed, certain experiments carried out on a certain material have showed that under all other conditions the same tightening force increased from 37 kg to 43 kg »

The means according to the invention also Another technical advance achieved with three-phase motors »The motor torque is used both when starting and significantly increased even with the usual slip speeds. This

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The result determined by experiments clearly shows that the flux Fp passing through the windings S generates an engine torque.

A fourth factor of superiority is based on the fact that the efficiency of the motor and its power factor as well be improved. So increased with an engine of 0.5 hp the efficiency from 52 to 55 $ and the power factor of

0.59 to 0.60. Furthermore, the advantage of the good cohesion of the rotor, which also exists with three-phase current supply, must be pointed out, which after the injection of the non-magnetic metal forms an integral whole with the deflection ring. Ä

Finally, it should be noted that even with three-phase current supply, the magnetic attraction forces for both the attraction as well as for holding in a considerable range of the values of the ratio S- / S is considerably increased will.

The invention can of course be modified. For example, although the embodiment described is preferable is, the deflection ring form an independent arrangement, and the inner ring 43 can be different from the short-circuit ring of the rotor be.

Furthermore, the agents according to the invention are from

independent of the type of mechanical brake used and can be attached to any type of brake.

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Claims (1)

Claims 1 ο) Brakeable electric motor with a Power failure-responsive mechanical brake with a rotor ring, which deflects the magnetic flux of the stator to a brake disc sliding on the motor shaft, which is non-rotatably connected to the rotor and is moved elastically to a fixed brake disc, with the deflection ring made of magnetic metal by radial non-magnetic walls in sectors is divided, characterized in that the deflector ring (22) has at least one short-circuit winding (46) for the flow of the induced currents and two possible paths (F ^, F ₂ ) ^ ** ² * ^the circulation of ^the magnetic stator flux (F) has, one of which runs outside this turn and the other through it. 2 ·) Brakeable motor according to claim 1, characterized in that the deflector rim is a sequence of around the shaft (11) of the rotor has short-circuit windings (S) distributed around the rotor, each of which is formed by two successive partitions (45) of the baffle which are made of a non-magnetic metal (22) and is formed by two rings connected to these walls, one of which (43) on the inside of the baffle and the other (46) is opposite on its outside and the brake disc. 3 ·) Brakeable motor according to claim 2, characterized in that the on the outside of the deflector rim (22) lying ring (46) arranged parallel to the circumference of the ring at a non-zero distance therefrom is. 4.) Brakeable motor according to claim 2, characterized 109877 / M? / « characterized in that the inner ring (43) is the one which connects the rods (41) of the cage anchor to one another. 5 ·) Brakeable motor according to claim 2, characterized in that the Kurzsohlusswindungen (S) through Pouring a non-magnetic metal into radial slots (25) of the deflector rim (22) and on the inside and outside the same formed annular grooves (28, 29) are made. 6 ·) Brakeable motor according to claim 5, characterized in that the hat (29) of the inside of the deflector ring (22) with hats parallel to the motor shaft (11) and intended to form the rods (41) of the short-circuit armature (34) of the rotor is in connection, with all these hats filled by the metal injected under pressure. 7 ·) Brakeable motor according to claim 2, characterized in that the deflection ring (22 :) is annular and is attached to the rotor by means of its inner ring (43). 8 ») Brakeable motor according to claim 3, characterized characterized in that the outer ring (46) of the short-circuit turns (S) at such a small distance from the circumference of the ring (22) is that when starting and at full load, the magnetic circuit running between the circumference of the ring (22) and this ring (46) is saturated 9) A method for producing a brakable motor according to claim 1, characterized in that the deflection ring (22) is formed by a one-piece part made of ¥ iron, that the short-circuit windings (S) are produced in this part by injecting a non-magnetic metal under pressure , and that the central opening of the wreath here- 109877/01? / * is bored up to the base (30) of the radial partitions (45). 10 ·) Brakable motor according to claim 1, characterized by using it with a single-phase supply to the stator. 109827 / M.? / «