DE29714740U1 - Electrical machine - Google Patents

Description

Electric machine

The invention relates to an electrical machine with a closed motor housing formed by an outer casing and two bearing shields for a rotor with a rotor shaft and a stator housing with a stator laminated core and stator winding, whereby a coolant guide is provided in the stator housing, a cooling air guide between the casing casing and the stator housing for an internal air flow and axial air guide channels are provided in the rotor.

An encapsulated electrical machine of this type is known from DE-U-18 13 190. In the known machine, a cooling pipe coil for the coolant flow is cast into an inner casing that forms an annular channel with the outer casing of the double-walled metal stator housing, whereby the annular channel between the outer and inner casing of the stator housing serves to guide an internal air flow. Bearing shields are attached to the stator housing of the known machine, in which the shaft of the rotor is mounted via bearings. A fan is arranged on the drive side of the rotor shaft, which moves the internal cooling air flow in a circular or looped manner, whereby the cooling air flows back to the fan through axial air guide channels of the rotor.

The object of the invention is to provide an encapsulated liquid-cooled electrical machine of the type mentioned above, which has additional air cooling by means of circulating internal

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air flow, so that the invention is also suitable for higher-performance motors, in particular for driving rail vehicles, and this electric drive is characterized by a relatively low motor weight and a small installation space.

The solution to this problem according to the invention is characterized in claim 1. Advantageous embodiments of the invention are specified in claims 2 to 12.

According to the invention, the rotor shaft is designed as a hollow shaft and is effectively cooled by the internal air flow. In addition, the hollow shaft significantly reduces the rotor weight and thus the motor weight.

A cuboid-shaped motor housing forms a space-saving, simple design, whereby larger cooling fins can be provided on the stator housing in the corner areas of the motor housing.

For the encapsulated, liquid-cooled electrical machine according to the invention, which is additionally acted upon by an internal air flow, it is advantageous if a fan sitting on the rotor shaft guides the cooling air over an axial, ring-shaped cooling air channel between the outer casing of the motor housing and the water-cooled stator housing casing over the length of the motor and if the cooling air is guided from the end bearing plate over the winding heads of the stator and through a gap between the stator and rotor as well as through the air guide channels of the rotor and also through the hollow shaft of the rotor back to the fan. This internal air circulation enables the motor heat to be effectively transferred to the liquid-cooled

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cooled stator housing shell. This in turn allows an increase in machine performance due to the improved cooling system.

Further details and advantages of the invention are explained below based on the embodiments shown in the drawing.

Show it:

Figure 1 shows an embodiment of an electrical machine according to the invention in axial half section,

Figure 2 shows a further advantageous embodiment of an electrical machine according to the invention in axial half section, 15

Figure 3 shows a corner area of a cuboid machine housing with a section of the stator housing that carries cooling fins.

In the embodiment according to Figure 1, an outer casing 1 and two bearing shields 2, 3 form the housing of the electrical machine. Together with a stator housing 6, a stator laminated core 7, the stator winding 8, 8' and the rotor 4 sitting on the rotor shaft 5, the electrical machine is designed in an encapsulated version. The rotor shaft 5, which is mounted in bearings 25, 26 of the bearing shields 2, 3, is designed as a hollow shaft. The stator housing 6, which can be manufactured as a cast part, contains a coolant guide 9, whereby a helical cooling pipe layer can preferably be cast into the stator housing.

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4
In addition to liquid cooling, the electrical machine is also cooled by an internal air flow. For this purpose, the stator housing β forms an annular axial cooling air duct 10 with the housing outer casing 1, whereby the stator housing 6 can also have axially extending cooling fins 12'. To circulate the air, a fan 13 is arranged on the rotor shaft 5 near one bearing plate 2. The fan pushes the internal air flow through the axial cooling air duct 10 over the length of the motor to the other end bearing plate 3. The internal air flow cooled on the liquid-cooled stator housing 6 then passes over the winding heads of the stator winding and through the gap 14 between the stator and rotor 4 back to the fan inlet. A partial air flow of the cooled internal air flow passes through air ducts 11 of the rotor 4. Finally, another partial air flow is guided through the hollow shaft 5 of the rotor 4 back to the fan 13.

To cool the fan-side winding head 8' of the stator winding, guide ribs 15 for the cooling air flow are provided in the corner areas of the motor housing 1, 2, 3, so that partial air flows 16 of the cooling air are directed to the fan-side winding head 8'. In an advantageous embodiment, the stator housing 6 with the cooling ribs 12, 12', the guide ribs 15 and the coolant guide 9 can be designed as a single cast part.

As the embodiment according to Figure 2 shows, a motor suspension 17, 17' can also be molded onto the cast part of the stator housing 6. With this design, it is possible in a simple way to also mold the bearing plate 18 onto the stator housing 6. In this case, the molded bearing plate

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5
shield 18 is provided with cooling fins 19, which are

Internal air cooling flow can also be applied.

The stator housing 6, which can be inserted into the housing shell 1 as shown in Figure 2, is provided with insulating means 27, 27' between the bearing shields 18, 22 and the bearing outer rings 28, 29 of the bearings 25, 26 of the rotor shaft.
Thermal and/or electrical insulation can be provided.

To seal the cooling air duct, seals 20, 20' are provided between the fan outlet and the stator housing. Additional seals 23, 23' are provided between an air duct 21 of the bearing plate 18 and an air inlet 24 to the hollow shaft 5 of the rotor 4.

Claims (12)

GR 96 G 3937 »··* Protection claims 1. Electrical machine with a closed motor housing formed by an outer casing (1) and two bearing shields (2, 3) for a rotor (4) with rotor shaft (5) and a stator housing (6) with stator laminated core (7) and stator winding (8, 8'), wherein a coolant guide (9) is provided in the stator housing (6), a cooling air guide (10) for an internal air flow is provided between the housing outer casing (1) and the stator housing (6) and axial air guide channels (11) are provided in the rotor (4), characterized in that the rotor shaft (5) is designed as a hollow shaft and a cooling air flow is guided through the hollow shaft of the rotor (4). 2. Electrical machine according to claim 1, characterized in that the motor housing (1, 2, 3) is cuboid-shaped and the stator housing (6) has cooling fins (12) in the corner regions of the motor housing. 3. Electrical machine according to claim 1, characterized in that a fan (13) seated on the rotor shaft (5) directs the cooling air via an axial, annular cooling air channel (10) between the outer casing (1) of the motor housing and the water-cooled stator housing casing (6) over the length of the motor and that the cooling air is guided from the end bearing plate (3) over the winding heads of the stator and through the gap (14) between the stator (6, 7) and rotor (4) as well as through the air guide channels (11) of the rotor (4) and through the hollow shaft (5) of the rotor back to the fan. GR 9€ G 3937 .. ···· 4: Electrical machine according to claims 1 to 3, characterized in that for cooling the fan-side winding head (8 ¹ ) of the stator winding, guide ribs (15) for the cooling air flow are provided in the corner regions of the motor housing (1, 2, 3), which guide partial air flows (16) of the cooling air to the fan-side winding head. 5. Electrical machine according to claims 1 to 4, characterized in that the stator housing (6) with the cooling fins (12, 12'), the guide fins (15) and the coolant guide (9) is designed as a cast part. G. Electrical machine according to claim 5, characterized in that a helical cooling pipe coil is cast into the stator housing (6) as a coolant guide (9). 7. Electrical machine according to one of claims 1 to 6, characterized in that a motor suspension (17, 17') is molded onto the cast part of the stator housing (6). 8. Electrical machine according to one of claims 1 to 7, characterized in that the A bearing shield (18) is formed on the stator housing (6). 9. Electrical machine according to claim 8, characterized in that the molded bearing plate (18) has cooling fins (19) which can be acted upon by the cooling air flow. GR 96 G 3937 ♦ .· ·· ··. .··.···· 10. Electrical machine according to one of claims 1 to 9, characterized in that for guiding the cooling air flow, seals (20, 20' or 23, 23') are provided between the fan outlet and the stator housing (S) as well as between the air guide (21) in the bearing plate (18) and the air inlet (24) to the hollow shaft (5) of the rotor (4). 11. Electrical machine according to one of claims 1 to 10, characterized in that the bearings (25, 26) of the rotor shaft (5) are assigned insulating means (27, 27') between the bearing outer rings (28, 29) and the bearing shields (18, 22). 12. Electrical machine according to claim 11, characterized in that the insulating means (27, 27') form thermally insulating and/or electrically insulating intermediate layers.