DE2100663A1 - Electric machine, especially miniature motor - Google Patents

Description

P 61.22 D4 _Ra . _R 4.1.1971 HDP class

PAPST-MOTOREN KG
7742 St. Georgen / Black Forest

Electric machine, especially miniature motor

The invention relates to an electrical machine and in particular to a miniature motor, with a stator and a rotor, the latter having a peripheral part connected to a shaft that cooperates with the stator.

Electrical machines of this type in the form of miniature motors serve, for example, to drive small axial fans tape recorders, turntables, office machines, etc. With external rotor motors, i.e. motors with the rotor outside of the stator is arranged and rotates around it, it is known that the squirrel cage of the rotor at the same time to be designed as a rotating housing and by means of a shaft bushing cast into this rotor housing, which is usually is made of steel to create a firm connection to the shaft the shaft is usually in the Pressed-in shaft bushing to obtain a non-rotatable connection .

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With such an external rotor motor, the rotor has roughly the shape of a cup, with the shaft attached in the bottom of the cup and the walls of the cup from the electromagnetically active parts are formed; the bottom of the cup consists of these known constructions the material of the squirrel cage, so usually from Aluminum. Since one is often forced to use aluminum that is as pure as possible for reasons of the lowest possible cage resistance To use it, but on the other hand it has relatively poor strength values, the rotor base has to be quite thick and provide reinforcement ribs, especially if there are air holes or air ducts in this floor Need to become. This has the consequence that the height of the end windings of the stator is limited, if only a certain one maximum axial length of the entire motor is permissible. The production of thin aluminum floors is also very important in terms of casting technology difficult. Furthermore, difficulties can arise in the permanent fastening of the shaft bushing to be arranged in the rotor base result, the long-term alignment of the inside of the rotor with the shaft in such rotors with a pure aluminum housing usually a critical point.

In the case of internal rotor motors, i.e. motors in which the rotor is rotatably arranged inside the stator, development is continuing also to build engines with a short length. For this purpose one uses in a known construction a fixed bearing support tube with inserted bearings. The rotor is hollow inside; a shaft is firmly connected to it, and this shaft is inserted into the bearings of the bearing support tube and rotates in them. The rotor then rotates around the fixed bearing support tube around and acts on its outside via the electromagnetically effective air gap with the around it arranged stator together. With this arrangement, the rotating parts of the internal rotor motor are mechanical

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constructed analogously to the previously described external rotor motor, so that here, too, the same difficulties as already described above with regard to the mechanical Result in strength of the rotor base. In addition, this construction of an internal rotor motor has a slight axial Has length, but is more expensive than the known constructions of internal rotor motors, in which the laminated core of the Rotor, a shaft is attached by pressing or the like. And this shaft is mounted in the two end shields of the motor is. Efforts are therefore made to make the production of this type of construction, which is provided with a bearing support tube, cheaper.

It is therefore an object of the invention to at least partially avoid the disadvantages mentioned.

According to the invention, this is the case with an electrical system mentioned at the beginning Machine achieved in that the peripheral part of the rotor via a molded piece made of sheet metal with the shaft connected is. Such a shaped piece is preferably made of a suitable steel, for example by stamping. It shows with a small thickness, the required strength, so that Even if the axial length of the motor is short, the winding heads of the stator should be dimensioned sufficiently high in the case of an external rotor motor can be. Furthermore, there is an excellent and very reliable mechanical connection of the rotor with of the shaft, which does not change even after a long period of time under the occurring mechanical loads.

In an advantageous development of the invention, the electrical machine designed so that the shaped piece is designed as a sheet metal disc, which on its outer edge in a suitable Way with the receiving part of the rotor and on yours Inner edge is connected to a bushing, which in turn is rotatably connectable to the shaft. Such Sheet metal disc, e.g. designed similar to a plate can be, can be very easy and inexpensive means

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conventional mass production methods and is very dimensionally stable, especially _s when it is curved according to a further advantageous feature of the invention. Sufficiently large holes for ventilation can also be provided in it without difficulty.

A particularly simple and advantageous construction is obtained in that the sheet metal disc has recesses on its edge is provided, and that this edge is cast into a part of the rotor and preferably a short-circuit ring of the rotor is. The disk can then be fastened in carry out one operation with the casting of the squirrel cage, so that there are practically no additional costs compared to the known constructions. Such pouring is also one Such a fitting is much less problematic than casting a thin aluminum floor.

Further details and advantageous developments of the invention result from the exemplary embodiments of the invention described below and shown in the drawing.

Show it :

Fig. 1 is a section through part of the fan, which fan is from an electrical according to the invention Machine driven in the form of an external rotor motor will, on a larger scale; the upper half of Fig. 1 shows a section, which runs at an angle of 90 ° to the cut towards the lower half,

2 shows a blank of a shaped sheet metal piece after punching but before bending; such a fitting in a curved shape is used in the motor according to FIG. 1 to connect the peripheral part of the rotor to the Wave,

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Fig. 3 shows a longitudinal section through the blank according to FIG. 2 in its final, curved shape.

4 shows an individual illustration which shows a method step in the connection of a shaft bushing with the central opening of the sheet metal molding according to FIG. 3, in an enlarged view Scale,

FIG. 5 shows a representation of the bent part with the shaft bushing fastened to it, after the end of what is shown in FIG. 3 Process step j

6 shows a blank of a second embodiment of a sheet metal molding,

7 shows a longitudinal section through the blank according to FIG. 6, in its final, curved shape,

8 shows a longitudinal section through an external rotor rotor with a cast-on short-circuit cage, the sheet metal molding 7 is cast in the upper short-circuit ring of this rotor,

FIG. 9 shows a representation with two different top views of the rotor according to FIG. 9, seen along the lines IX-IX of Fig. 8,

Fig. Io shows a longitudinal section through another embodiment a rotor, here a rotor for an internal rotor motor,

11 shows an embodiment, which is a further according to the invention Connection of the peripheral part of a rotor with a shaft shows

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12 shows a partial illustration of an internal rotor motor, with a connection according to the invention of shaft and rotor, and

13 shows a further embodiment of the connection of the peripheral part of a rotor to a shaft.

14/15 show arrangements for an increased supply of cooling air in an electric motor according to the invention.

In the following description, the terms "left" and "right" each refer to the graphic representation on the individual figures,

Fig. 1 shows a longitudinal section through part of an axial fan lo, the one designated by 11 in its entirety External rotor motor is driven. The fan Io has an outer housing, which is essentially made of a cast Form piece 12 consists. On one end of this outer housing 1 a flange 14 is attached to a mounting plate 15.

On the mounting plate 15 is by means of screws 16, of which only one is shown, a bearing support tube 17 is attached, on which the stator 13 of the motor 11 is attached. Inside the Bearing support tube 17, two plain bearings 18, 19 made of sintered material are attached, between which a piece of felt 2o is arranged, which serves as a lubricant depot. Furthermore, two disks 24 are fixed in a recess 23 of the mounting plate 15, the first Thrust bearings for a shaft 25 are used. At its left end (with reference to FIG. 1) this has a recess for a snap ring 26 on, which holds four disks 27, which form a second axial bearing for the shaft 25 with the right end face of the plain bearing 18. The shaft 25 is thus held axially in a certain position by the two axial bearings 24 and 18 27, while the two Slide bearings 18 and 19 guide the shaft 25 radially.

A stator lamination packet 3o is attached to the bearing support tube 17,

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inserted into the windings 31 and 31 'in a known manner are, the connections 32 and 32 'in an insulating tube 34 guided and attached to a connection element 35 which is fastened in the cast fitting 12 and which contains two solder contacts 33 and 33 ', are connected. The windings 31 and 31 'have end turns of which the left are labeled 36 and the right are labeled 37.

On the shaft 25 is a bushing 41, which is preferably used as a rotating part is made of steel, non-rotatably attached. In turn, a molded piece made of sheet steel is attached to this bushing 41 42 non-rotatably attached; this shaped piece 42 has a total of eight openings 43 for the passage of air. It's up to his Outer edge provided with bent ends in the form of sheet metal tabs 44, which in the left short-circuit ring 45 with a Outer rotor housing provided with a short-circuit cage (as peripheral part) are poured in; the peripheral part 46 also has a laminated core 47 and a right short-circuit ring 48. Between the left Short-circuit ring 45 and the right short-circuit ring 48 run rods cast in grooves of the laminated core 47, which are indicated at 49 and also belong to the short-circuit cage; this The cage can be made of pure aluminum, for example.

Fan blades are welded directly onto the peripheral part 46, two of which are shown at 52 and 53.

Fig. 2 shows the shaped piece 42 in the unbent, flat state directly after punching. It has an opening in its center 54, which has irregular edge contours, namely three each Lateral bulges 55 offset by 120 °, the purpose of which will be described below. On the edge are between the remaining eight sheet metal tabs or sections 44 cutouts 57 punched in such a way that the sheet metal tabs 44 on their free ends have widenings 58, like the Figures 2 and 3 clearly show. This results in excellent anchoring of the sheet metal tabs 44 in the short-circuit ring

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As Fig. 3 shows, the sheet metal tabs 44 are bent approximately at right angles to the plane of the blank shown in Fig. 2, and indeed they are bent about in an arc. Here, as FIG. 1 clearly shows, the diameter of the bent sheet metal tabs 44 are chosen so that they are very close to the outer circumference of the short-circuit ring 45. Furthermore, the distance is theirs The ends of the laminated core 47, which distance is designated by "h" in FIG. 1, are selected to be as large as possible. Both measures contribute significantly to the fact that the resistance of the short-circuit ring 45 is only increased by the sheet metal tabs 44 is that in the finished engine compared to the construction without cast sheet metal tabs 44 there is at most a slight reduction of the output torque results. However, tests have shown that such a reduction in practice in the The normal range of specimens for the motors is within the limits of the specified rules for the distance "h" and the diameter of the fitting 42 are complied with.

In order to obtain a secure connection between the shaft 25 and the bushing 41 even after a long period of operation, one can tread different paths. For example, the bushing 41 can be welded to the fitting 42, in particular by pulse welding, or these parts can be joined together by brazing, in particular by induction brazing; a A particularly simple method for fastening the bushing 41 in the shaped piece 42, the opening 54 of which is the one shown in FIG Has shape, that is, is provided with the bulges 55, is shown in FIGS.

Fig. 4 shows how the shaped piece 42 with the inserted socket is placed on a holder 6o, then a hold-down device lowered, which clamps the two parts 41 and 41.

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Then an upsetting tool 62 is lowered from above in the direction of the arrows drawn, its working end face 62 'is conical, and this deforms the outer circumference of the socket 41 in the manner shown in Fig. 5, wherein through the pressing down of the material creates a bead 63 and at the same time the material of the bushing 41 into the bulges 55 (FIG. 2) is pressed and thus a stable, non-rotatable connection between the molded piece 42 and the bush 41 is created. Together with the The bead 63 then engages around the lower edge 64 of the bushing 41, so that an extremely durable connection is created. Finally, the bushing 41 is rotated along the dot-dashed plane 65 shown in FIG. 5, so that it has the The form shown in Fig. 1 is obtained. - The same type of attachment can also be used in the exemplary embodiments described below. Due to the conical shape of the working Forehead 62 ″, the process described is significantly supported.

Fig. 8 shows a second embodiment of one labeled 7o Rotor for an external rotor motor, for example could be used in place of the rotor 46 of FIG. 1 and is of a shape similar to this. The rotor 7o has a laminated core 71 with a cast short-circuit cage, e.g. made of pure aluminum. An upper short-circuit ring 72 and a lower short-circuit ring 73 of this cage are shown. Between Rings 72 and 73 lie connecting rods which run in grooves (not shown) in the laminated core 71.

In Fig. 8 are dashed ring edges 79 and 79 ' of a tool 69, 69 'indicated in the casting position. In this Position these ring edges 79, 79 'from both sides into the Fitting 74 pressed in by approx. L / lo mm to counteract the shot Seal material when pouring.

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A shaped sheet metal piece 74 is located in the upper short-circuit ring 72 fastened, namely in that its edge is cast into this ring, also here between the end of the molded piece 74 and the laminated core 71 is a distance "h" which is only filled with cast material, so as to reduce the resistance of the short-circuit ring as low as possible. The shape of this shaped piece 74 in the flat, unbent state, That is, the shape of the blank can be seen from FIG. 6, and the shape in the bent state from FIG. 7. As from FIGS It can be seen, the molding 74 has eight sheet metal tabs 75 on its edge, in which holes 76 are punched to ensure a good To effect anchoring in the short-circuit ring 72. These lobes are bent in the manner shown in Fig. 7, and at the same time the shaped piece 74 is arched, as shown in FIG. 7 by the angle '- ^ -. This gets the shaped piece 74 has a particularly great rigidity. Here, too, a bush 78 is inserted into a central recess 77, which is used to connect to a shaft not shown in FIG.

The mold halves 69, 69 'of the die casting tool for production of the electric motor according to the invention have circular rings Pressure webs 79, 79 ', which clamp the molded piece 74 so tightly that a certain material deformation occurs in the vicinity of the surface of the molded piece and thereby also the emergence an undesirable very thin casting skin on the exposed surface of the molded piece 74 is prevented. These Material deformation on the shaped piece 74 also has a dimensionally stable effect The catch pin 82 of the tool is used to center the molding 74 during the casting process.

FIG. 9 shows in the left half a view of the rotor 7o according to FIG. 8 from above and in the right half a view of the same rotor 70 from below, each based on FIG. 8. In the left half are those intended for balancing Holes marked 8o and 81 in the right half.

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Fig. Io shows a rotor 85 for an internal rotor motor; this rotor 85 is also a squirrel cage rotor formed and has an upper short-circuit ring 86 and a lower short-circuit ring 87, which by in grooves of the Laminated core 88 cast rods (not shown) are electrically connected to one another. - The upper ring 86 has a Turning 88, into which a stamped part 89 is pressed and by embossing 9o of the short-circuit ring 86 in its position is being held. Here, too, a shaft 91 is pressed into the inner recess of the punched part. The stamped part is a So-called fine-stamped part, the tool of which has greatly reduced cutting gaps, so that the cut surface over the thickness of the punched part is as true to size as possible (small fracture area). In this way, the dimensions can be adhered to more precisely.

Fig. 11 shows another type of attachment for the peripheral part 93 of a rotor, of which only a section is shown, namely a part of the laminated core 94 with a cast-on upper short-circuit ring 95, as well as a sheet metal disk 96, which is connected in its center to a socket 97, in turn a shaft 98 is pressed in.

The short-circuit ring 95 is cast here so that it has a number has upwardly projecting pins, one of which is shown in FIG is. At the points where these pegs are located, the disk 96 is provided with holes loo, so that the disk can be placed on the ring 95. Then the pins 99 are riveted by means of a suitable device, the The rivet heads Io3 shown in FIG. 11 arise. You get so a secure connection of the short-circuit ring 95 with the he 96 and thus with the wave 98.

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Fig. 12 shows a schematic representation of a construction, which is preferably suitable for an internal rotor motor and makes it possible to use a particularly long bearing support tube. The rotor is denoted by Ho and the stator by 111 here. A stationary bearing support tube is located inside the rotor Ho 112, which can be constructed and arranged similarly to the bearing support tube 17 according to FIG. 1. In the bearing support tube 112 two self-lubricating bearings 113 are arranged, and in these a shaft 114 rotates, at the upper end of which a bush 115 is attached. A hat-shaped sheet metal molding is attached to the socket 115 116 attached, with its central, raised part, while its outer edge is directly on the laminated core 117 of the Rotor llo rests and is attached by casting by means of an upper short-circuit ring 118 there. The fitting 116 thus forms part of the laminated core of the rotor llo in this construction.

Fig. 13 shows a further solution according to the invention, the predominantly is intended for an internal rotor motor, but under certain conditions it is also advantageous for an external rotor motor can be used. On a shaft 121 is also a socket 122 is attached here, and a deep-drawn, cup-like sheet metal molding 123 is firmly attached to this socket 122, e.g. by one of the aforementioned methods. This shaped piece 123 is in the inner bore of a designated 124 Rotor circumferential part pressed in such a way that a frictionally engaged Connection is created, which can safely transmit the torques occurring during operation. Here is between the short-circuit rings 125 and 126 on the one hand and the fitting 123 on the other hand each have a radial distance. In the hereby resulting annular gaps 127 and 128 takes effect during manufacture a tool that presses the laminated core 124 together.

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If you turn one with a squirrel cage Rotor of an external rotor motor removes the inner bore so that the groove webs are reduced in size and takes the place of the turned one Material a molded piece 123 made of soft magnetic material of a certain wall thickness, one obtains a so-called Tubular rotor in which a tubular conductor layer and a cage short-circuit winding are magnetically connected in series are. This gives a torque characteristic

for
ristic, which * # in some cases is advantageously composed of the superposition of the characteristics of a squirrel cage rotor and a tubular rotor (solid rotor). In this case, the molded piece 123 is used twice in a very advantageous manner.] FIGS. 14/15 show relief-like elevations and depressions 13o in the molded piece 74 which provide increased cooling! Air supply to the inside of the motor is used when the fitting rotates during operation of the motor. Here, in FIG. 14, blade-like elevations 131 and 132 are arranged on both sides of the shaped piece 74 according to section AA and in different circles 131/132 and 131 '/ 132' for both directions of rotation.

15 shows incised and bent out in variation thereto Tabs 133/134 of greater radial width, also for both directions of rotation.

The invention thus allows in a simple manner rotors and in particular squirrel cage rotors of motors and especially small motors safely with the associated shaft connect, these rotors securely retain their shape even after long operation and a low one due to their structure allow axial length of the associated motor. Casting technology is also the production of electric motors according to the invention less problematic than the known arrangements.

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Claims (1)

PAPST-MOTOREN KG P 61.22 D 4 St. Georgen 4.1.1971 HDP class Protection claims M J Electrical machine, in particular a miniature motor, with a stator and a rotor, the latter with one having a peripheral part connected to a shaft which cooperates with the stator, characterized in that that the peripheral part (46; 7o; 85; 93; 124) of the rotor connected to the shaft (25; 79; 91; 98; 121) via a shaped piece (42; 74; 89; 96; 123) made of sheet metal is. 2. Electrical machine according to claim 1, characterized in that that the shaped piece is designed as a sheet metal disc (42; 74; 96), which on its outer edge (44; 75) in a suitable Way with the peripheral part (46; 7o; 93) of the rotor and on its inner edge (54; 55; 77) with a bush (41; 78; 97) is connected, the latter in turn being rotatably connectable to the shaft (25; 79; 98). 3. Electrical machine according to claim 2, characterized in that the sheet metal disc (96) has recesses on its edge (loo) has that these recesses (loo) of projections (99) of the rotor (93) are penetrated, and that on the side of the sheet metal disc (96) facing away from the rotor these projections (99) are riveted onto the sheet metal disc (Io3) (FIG. 11). 4. Electrical machine according to claim 2, characterized in that the sheet metal disc (42; 74) has recesses on its edge (57; 76) is provided, and that this edge is cast into a part (45; 72) of the rotor (46; 7o) (Figures 1 to 9). 209830/0279 -15- 5. Electrical machine according to claim 4, characterized in that that the sheet metal tabs (44; 75) lying between the recesses on their outer Ends widened (58). 6. Electrical machine according to claim 4 or 5, characterized in that the edge of the sheet metal disc (42; 74) in a short-circuit ring (45; 72) of the rotor (46; 7o) is cast. 7. Electrical machine according to one of claims 4-6, characterized in that at least individual M cuts (44; 75) of the cast-in edge of the sheet metal disc (42; 74) in the direction of the peripheral part (46; 7o) of the rotor are bent. 8. Electrical machine according to claim 7, characterized in that the bent portion (44) of the cast edge in the vicinity of the outer circumference of the cast part (45) lie (Fig. 1). 9. Electrical machine according to claim 7 or 8, characterized in that between the ends of the bent sections (44; 75) of the sheet metal disc (42; 74) and the laminated core (47; 71) of the rotor each have a section M (h) cast material lies. lo. Electrical machine according to one of Claims 2 to 9, characterized in that the sheet metal disc (74) is arched (Figs. 7 and 8). - 16- 209830/0 279 11. Electrical machine according to claim 1, characterized characterized in that the shaped piece is designed as a preferably approximately hat-like part (116) is, whose raised central part is connected to the shaft (114) and whose edge part is through a short-circuit ring (118) cast onto the laminated core (117) with the laminated core of the rotor (TIo) is mechanically connected (Fig. 12). 12. Electrical machine according to claim 1, characterized in that the shaped piece (123) is cup-shaped is designed that the bottom of this cup-shaped fitting (123) with the shaft (121) is connected, and that the peripheral part of this molding with the inside of the hollow Rotor (124) is connected (Fig. 13). 13. Electrical machine according to claim 12, characterized characterized in that the rotor (124) as an external rotor rotor is designed that its inside is turned out, and that with the inside of the Rotor (124) connected peripheral part of the cup-shaped molding (123) as a soft magnetic layer is designed to have a so-called mixed torque characteristic to be obtained (Fig. 13). 14. Electrical machine according to claim 1, characterized in that that the shaped piece formed from sheet metal is designed as a fine-stamped part (89), the between the shaft (91) and a part (86) of the rotor (85) is arranged (Fig. Lo). - 17 - 209830/0279 15. Electrical machine according to claim 14, characterized in that that the fine blanking (89) between the shaft (91) and a · on the laminated core (88) of the Rotor (85) provided short-circuit ring (86), and that on the short-circuit ring (86) embossments (9o) provided for attaching the fine-stamped part (89) s i η d (F i g. 1 ο). 16. Electrical machine according to one of claims 1 to 15, characterized in that the shaped piece (42) is provided with recesses (43) for the passage of air. 17. Electrical machine according to one of claims 1 to 13, characterized in that the shaped piece welded on its inside to a bushing that can be connected non-rotatably to the shaft, in particular pulse welded, is. 18. Electrical machine according to one of claims 1 to 13, characterized in that the shaped piece on its inside with a socket rotatably connectable to the shaft by brazing, preferably Induction brazing. 19. Electrical machine according to one of claims 1 to 13, characterized in that the shaped piece (42) has an approximately circular recess on its inner edge (54) has that this recess (54) has a circular shape at at least one point having a different edge contour (55), and that a bushing that can be connected to the shaft (25) in a rotationally fixed manner (41) is brought into engagement with this edge contour (55) by an upsetting process (FIG. 4), around a non-rotatable Form connection between her and the fitting (42). 209830/0279 20. Electrical machine according to claim 19, characterized in that that the approximately circular recess (54) has bulges (55) distributed on its circumference, into which the material of the bushing (41) displaced during the upsetting process (FIG. 4) flows. 21. Electrical machine according to claim 19 or 2o, characterized characterized in that the bush (41) in the compressed state (Fig. 1,5) both broad sides of the shaped piece (42) encompasses (63, 64). (in particular according to claim 16 / 22. Electrical machine according to one of claims 1 to 21 ν characterized in that the shaped piece (74, 42, etc.) has relief-like elevations and / or depressions 13o. 23. Electrical machine according to claim 22, characterized in that the e.g. bead-shaped elevations and Wells in different circles (131/132 and 131 '/ 132') are arranged in opposite directions (Fig. 14). 24. Electrical machine according to claim 22, characterized in that the elevations or depressions through incised and bent out, radially wide flaps 133/134 are formed. (Fig. 15). 25. Device for producing an electrical machine according to one of claims 19, 2o, 21, characterized in that that the working end face 62 'of the upsetting tool 62 is conical. - 19 - 209830/0279 26. Electrical machine according to one of claims 1 to 25, in particular according to claim 1 to lo _s, characterized in that the shaped piece (74, 42) is provided with ring-like zones on the surface of very small press-in depth. 27. Device for producing an electrical Machine according to Claim 26, characterized in that it is a die-casting tool, its mold halves (69, 69 ') have annular pressure webs (79, 79') which seal the molded piece and clamp in a shape-stabilizing manner, preferably a catch pin (82) is used to center the shaped piece. 20983 0/0279