ELECTRIC MACHINE, GEARBOX MOTOR WITH AN ELECTRIC MACHINE AND VEHICLE WITH AN ELECTRIC MACHINE

Description

TECHNICAL AREA

[0001] The invention relates to an electric machine, a geared motor with an electric machine and a vehicle with an electric machine. STATE OF THE ART

[0002] In electric machines, it is known to cool the stator to dissipate waste heat generated during operation. Some systems incorporate cooling tubes within the stator, which are part of a cooling system and through which a heat transfer fluid flows. The cooling system may also include a pump for circulating the heat transfer fluid and a heat exchanger. A disadvantage of known stator manufacturing methods is that they are relatively complex and increase the overall cost of manufacturing the electric machine.

[0003] From WO 2016 / 173812 A1, an electric machine with a cooled stator is known. REVELATION OF THE INVENTION

[0004] One object of the invention is therefore to provide an improved electric machine, an improved geared motor, and an improved vehicle. In particular, the cooling of the stator should be possible with relatively less technical effort.

[0005] The object of the invention is solved by an electric machine according to claim 1, which comprising a first bearing shield and a second bearing shield, a stator arranged between the two bearing shields with a stator lamination stack and stator windings arranged therein, a rotor arranged in the stator with a rotor shaft rotatably mounted in the two bearing shields and cooling channels arranged completely in and surrounded by the stator lamination stack.

[0006] In other words, cooling channels run through the stator lamination stack, the (circumferential) boundaries of which are completely formed by the stator laminations of the stator lamination stack.

[0007] The object of the invention is further solved with a geared motor comprising a gearbox and an electric machine of the aforementioned type coupled to the gearbox, wherein a cooling and / or lubrication circuit of the gearbox is hydraulically connected to the cooling channels of the electric machine.

[0008] Finally, the task can also be solved by a vehicle with at least two axles, at least one of which is driven, the said drive being at least partially or temporarily provided by the above-mentioned electric machine or by a geared motor of the above-mentioned type.

[0009] The proposed measures overcome the aforementioned disadvantages. In particular, they enable stator cooling with less technical complexity. Specifically, the cooling channels are directly enclosed by the stator laminations of the stator core; no additional cooling pipes are required. This means that the cooling medium comes into direct contact with the stator laminations. Because the (circumferential) boundary is entirely formed by the stator laminations of the core, a motor housing, which typically forms part of the (circumferential) boundary of the cooling channels, can be eliminated. The electric machine can therefore be of a particularly simple and lightweight design.

[0010] The cooling channels can thus be produced, for example, directly by punching or cutting corresponding openings in the individual stator laminations. When the stator laminations are stacked on top of each other, the cooling channels are formed. If the stator laminations are not twisted during stacking, the resulting cooling channels run axially parallel to an axis of rotation of the rotor shaft. If, however, the stator laminations are twisted slightly relative to each other during stacking, the cooling channels are inclined, so that they run helically around the axis of rotation of the rotor shaft. It is advantageous for the cooling channels to be open only at the end faces of the stator lamination stack. This allows the stator laminations to be identically shaped.

[0011] It is particularly advantageous to use oil as the cooling medium, as this does not lead to corrosion of the stator laminations. For example, oil from a gearbox to which the electric motor is flanged or in which the electric motor is integrated can be used as the cooling medium. Waste heat from the electric motor and the gearbox is transported by the lubricating oil to a heat exchanger, for example, and then dissipated into the environment. In this way, the electric motor and the gearbox are cooled. In this case, a combined cooling and lubrication circuit is used, with oil as both the cooling medium and the lubricant. This means that the lubricating oil functions not only as a heat transfer medium but also as a lubricant. The oil then fulfills multiple functions by lubricating and cooling the gearbox and also cooling the electric motor. While this is advantageous, it is not essential.It is also conceivable that separate circuits are provided for lubrication and cooling. However, even in a separate cooling circuit for the gearbox, oil could be used as the cooling medium for the electric motor and the gearbox.

[0012] It is particularly advantageous if the electric machine is arranged without a separate housing (i.e., without its own housing) in a common housing for the electric machine and the gearbox. In other words, the stator lamination stack borders directly on its circumference (without a circumferentially arranged motor housing contacting the stator lamination stack) an interior space of the common housing of the geared motor. In this way, the electric machine and the geared motor can be of a particularly simple and lightweight design. It should be noted here that the terms "motor," "motor housing," and "geared motor" are used within the scope of the invention solely for the sake of simplicity and do not restrict the operation of the electric machine to motor operation. Naturally, a motor and a geared motor can also be operated as a generator.

[0013] According to the invention, lines or channels for a cooling medium are arranged in the two bearing shields, which are hydraulically connected to the cooling channels in the stator lamination stack. This creates a distributor to the cooling channels in the stator lamination stack in a first bearing shield and a collector in a second bearing shield to collect the cooling medium that has passed through the cooling channels in the stator lamination stack and return it to the return line of the cooling circuit.

[0014] It is also advantageous if the first end shield contains lines or channels for a cooling medium that are hydraulically connected to the cooling channels in the stator core, and if the cooling channels of the stator core discharge into the surrounding area of ​​the electric machine in the area of ​​the second end shield. In this configuration, a distributor to the cooling channels in the stator core is again provided in the first end shield. However, no manifold is provided in the return line of the cooling circuit; instead, the cooling medium that has passed through the cooling channels in the stator core is discharged directly into the surrounding area of ​​the electric machine, for example, into the interior of a geared motor housing in which the electric machine is installed. The cooling circuit can thus be designed to be particularly simple.

[0015] Finally, it is advantageous if the two bearing shields are connected to the stator using tie rods. This prevents the stator laminations from drifting apart undesirably.

[0016] The above embodiments and further developments of the invention can be combined as long as they remain within the scope of protection of the claims. BRIEF DESCRIPTION OF THE FIGURES

[0017] Exemplary embodiments of the invention are shown in the accompanying schematic figures. These show: Fig. 1 a schematic representation of an exemplary electrical machine in half-section; Fig. 2 a somewhat more detailed representation of the stator lamination stack with one channel of the bearing shield isolated from the rest of the electrical machine in oblique view; Fig. 3 an enlarged section of the Fig. 2 in the upper area of ​​the arrangement shown there; Fig. 4 a cross-section through a stator lamination and Fig. 5 a schematic representation of a vehicle with an electric machine of the proposed type. DETAILED DESCRIPTION OF THE INVENTION

[0018] It is stated in the introduction that identical parts in different embodiments are provided with the same reference numerals or component designations, possibly with different indices. The disclosures contained in the description of a component can be applied analogously to another component with the same reference numeral or component designation. Furthermore, the positional indications chosen in the description, such as "top," "bottom," "back," "front," "side," and so on, refer to the figure directly described and illustrated and, in the event of a change in position, must be applied analogously to the new position.

[0019] Fig. 1 Figure 1 shows a half-section through a schematically represented electric machine 1. The electric machine 1 comprises a rotor shaft 2 with a rotor 3 mounted on it (not shown in detail here). The rotor shaft 2 is rotatably mounted about an axis of rotation A relative to a stator 5 by means of (rolling) bearings 4a and 4b. Specifically, the first bearing 4a is located in a first bearing shield 6, and the second bearing 4b is located in a second bearing shield 7. Furthermore, the electric machine 1a comprises a (central) housing section 8, which connects the first bearing shield 6 and the second bearing shield 7 and accommodates the stator 5. In this example, the first bearing shield 6, the second bearing shield 7, and the housing section 8 form the housing 9 of the electric machine 1a.

[0020] The stator 5 has several stator laminations 10, which form a stator lamination stack 11 or a stator body, as well as stator windings 12 arranged in the stator lamination stack 11. Furthermore, the stator 5 includes several cooling channels 13 extending longitudinally in the stator lamination stack 11. Additionally, lines or channels 14a, 14b are arranged in the first end shield 6 and the second end shield 7, which are hydraulically connected to the cooling channels 13 in the stator lamination stack 11.

[0021] The cooling channels 13 running in the stator lamination stack 11, as well as the lines or channels 14a, 14b, are part of a system in the Fig. 1 The cooling system of the electric machine, not fully illustrated, may also include a pump for a heat transfer medium and a heat exchanger (see also...). Fig. 5 A water-glycol mixture or oil, for example, can be used as a heat transfer medium in the cooling system.

[0022] Fig. 2 Figure 1 now shows a slightly more detailed representation of the stator lamination stack 11a with a channel 14a isolated from the rest of the electrical machine 1, in oblique view.

[0023] As from the Fig. 2 As can be clearly seen, the stator lamination stack 11a has several stator winding slots 15, which accommodate the stator windings 12. In the example shown, both the stator winding slots 15 and the cooling channels 13 run in the axial direction, i.e., parallel to the axis of rotation A. However, the stator winding slots 15 and the cooling channels 13 could also run obliquely, i.e., helically, around the axis of rotation A.

[0024] The channel 14a comprises an annular section 16, several branches 17 which open into the cooling channels 13 in the stator lamination stack 11a, and several spray nozzles 18 directed towards the stator windings 12.

[0025] Furthermore, the stator lamination stack 11a includes several recesses 19 for in the Fig. 3 Anchors not shown.

[0026] The cooling channels 13, the stator winding slots 15, and the recesses 19 can be produced, for example, by punching or cutting corresponding openings in the individual stator laminations 10a. When the stator laminations 10a are stacked on top of each other, the cooling channels 13, the stator winding slots 15, and the recesses 19 are formed. If the stator laminations 10a are not twisted during stacking, the cooling channels 13, stator winding slots 15, and recesses 19 are axially oriented. If the stator laminations 10a are slightly twisted relative to each other during stacking, the cooling channels 13, the stator winding slots 15, and the recesses 19 are inclined.

[0027] Additionally, the Fig. 3 an enlarged section from the Fig. 2 in the upper area of ​​the arrangement shown there, and the Fig. 4 shows a cross-section through a stator lamination 10a.

[0028] It should be noted here that channel 14a in the Fig. 2 and 3 For the sake of clarity, it is shown without the first bearing shield 6 that limits it. In other words, in the Fig. 2 and 3 Only the cavity forming channel 14a in the first bearing shield 6 is shown. It would also be conceivable that for the purposes of the Fig. 2 and 3 It is assumed that the first bearing shield 6 is made of a completely transparent material. In reality, however, it is usually made of a metal.

[0029] The Fig. 5 Figure 1 shows the electric machine 1 installed in a vehicle 20. The vehicle 20 has at least two axles, at least one of which is driven. The vehicle 20 is driven at least partially or temporarily by the electric machine 1. That is, the electric machine 1 can serve as the sole drive for the vehicle 20 or, for example, be used in conjunction with an internal combustion engine (hybrid drive).

[0030] Specifically, in the example shown, the electric machine 1 is connected via an optional gearbox 23 to the half-shafts 21 of the rear axle, to which the driven wheels 22 are mounted. In this example, the gearbox 23 includes the motor pinion 24 and the gear wheel 25. However, this is merely illustrative, and the gearbox 23 can also have a more complex design. It would also be conceivable, in principle, for the half-shafts 21 or wheels 22 to be driven directly, that is, without the gearbox 23.

[0031] The electric machine 1 and the gearbox 23 are installed in a common housing 26. In this case, the electric machine 1 does not have a separate motor housing; that is, the stator lamination stack 11 borders directly (without a circumferentially arranged motor housing contacting the stator lamination stack) on an interior space of the common housing 26, which also accommodates the gearbox 23. Fig. 5 A pump 27 is also shown, which draws lubricating oil from the common housing 26 with the help of the suction nozzle 28 and pumps it via a heat exchanger 29 on the one hand to the electric machine 1, but also on the other hand to lubrication points of the gearbox 23.

[0032] The arrangement coupled to the half-axles 21 thus forms a geared motor 30, comprising a gearbox 23 and an electric machine 1 coupled to the gearbox 23, wherein a lubrication circuit of the gearbox 23 is hydraulically connected to the cooling channels 13 of the electric machine 1.

[0033] Waste heat from the electric machine 1 and also from the gearbox 23 is transported to the heat exchanger 28 with the help of the lubricating oil and there released into the environment. In this way, the electric machine 1 and the gearbox 23 are cooled.

[0034] In the Fig. 5 A combined cooling and lubrication circuit is provided, using oil as both the cooling medium and lubricant. This means the lubricating oil functions not only as a heat transfer medium but also as a lubricant. While this is advantageous, it is not mandatory. Separate circuits for lubrication and cooling are also conceivable.

[0035] In the Fig. 1 bis 3In the examples shown, the cooling medium and / or lubricant that has passed through the cooling channels 13 is collected via channel 14b in the second bearing shield 7 and then returned to the return line of the cooling and / or lubrication circuit. However, it would also be conceivable that the cooling channels 13 of the stator lamination stack 11, 11a in the area of ​​the second bearing shield 7 open into the surroundings of the electric machine 1, in the example shown, into the common housing 26.

[0036] In the examples shown, the cooling channels 13 are only open at the end faces of the stator lamination stack 11, 11a. However, it would also be conceivable that radially outward-leading discharge channels are provided in the stator lamination stack 11, 11a, originating from the cooling channels 13.

[0037] In conclusion, it is noted that the scope of protection is defined by the patent claims. However, the description and drawings must be consulted for the interpretation of the claims. The features depicted in the figures can be exchanged and combined within the scope of protection of the claims. In particular, it is also noted that the depicted devices may, in reality, comprise more or fewer components than shown. In some cases, the depicted devices or their components may also be shown not to scale and / or enlarged and / or reduced in size.

Claims

1. Electric machine (1), comprising: - a first end shield (6) and a second end shield (7), in which channels (14a, 14b) for a cooling medium are arranged, - a stator (5) arranged between the two end shields (6, 7) with a stator laminated core (11, 11a) and stator windings (12) arranged therein, - a rotor (3) arranged in the stator (5) with a rotor shaft (2) rotatably mounted in the two end shields (6, 7), and - cooling channels (13) arranged completely in the stator laminated core (11, 11a) and surrounded by the same, which are open at the axial end faces of the stator laminated core, wherein the channels (14a, 14b) are hydraulically connected to the cooling channels (13), characterized in that one of the channels (14a) comprises an annular section (16), a plurality of branches (17) branching off from the annular section (16) which open into the cooling channels (13), and a plurality of spray nozzles (18) branching off from the annular section (16) and directed at the stator windings (12).

2. Electric machine (1) according to claim 1, characterized in that the cooling channels (13) are open only at end faces of the stator laminated core (11, 11a).

3. Electric machine (1) according to claim 1 or 2, characterized in that the cooling channels (13) of the stator laminated core (11, 11a) open into an environment of the electric machine (1) in the region of the second end shield (7).

4. Electric machine (1) according to any one of claims 1 to 3, characterized in that the cooling channels (13) run parallel to an axis of rotation (A) of the rotor shaft (2) or helically around the axis of rotation (A) of the rotor shaft (2).

5. Electric machine (1) according to any one of claims 1 to 4, characterized in that the two end shields (6, 7) are connected to the stator (5) by means of tie rods.

6. Geared motor (30), comprising a gear unit (23) and an electric machine (1) according to any one of claims 1 to 5 coupled to the gear unit (23), characterized in that a cooling and / or lubrication circuit of the gear unit (23) is hydraulically connected to the cooling channels (13) of the electric machine (1).

7. Geared motor (30) according to claim 6, characterized in that the electric machine (1) is arranged without a housing in a common housing (26) for the electric machine (1) and the gear unit (23).

8. Geared motor (30) according to claim 6 or 7, characterized in that oil is provided as a cooling medium and / or lubricant in the cooling and / or lubrication circuit of the gear unit (23).

9. Vehicle (20) with at least two axles, of which at least one is driven, characterized in that said drive is provided at least partially or temporarily by the electric machine (1) according to any one of claims 1 to 5 or by a geared motor (30) according to any one of claims 6 to 8.