Motor with improved cooling system and vehicle

Abstract

An electric machine (1, 1a... 1c) is disclosed, comprising a machine housing (2a... 2c), a stator (3) and a rotor (5). The stator winding (7) comprises a stack section (B), in which the stator winding extends within the stator lamination stack (6), and a stator winding head (C, C '), in which the stator winding extends out of the stack section (B). The machine housing (2a... 2c) comprises a first cooling system (9) based on a first cooling fluid and a separate second cooling system (10, 10 ') based on a separate second cooling fluid around the stator lamination stack (6). The individual second cooling system (10, 10 ') comprises a nozzle or hole (11, 11') which is directed towards at least one of the stator winding heads (C, C '). Furthermore, a vehicle (23) having such an electric machine (1, 1a... 1c) is disclosed.

Description

Technical Field

[0001] The present invention relates to an electric machine, which includes a machine housing, a stator fixedly arranged in the machine housing, a rotor shaft, and a rotor mounted on the rotor shaft. The rotor is rotatably arranged in the machine housing around a rotor axis through the rotor shaft. The stator includes a stator lamination stack and a stator winding arranged therein, where the stator winding includes a stacking section and a stator winding head. In the stacking section, the stator winding extends within the stator lamination stack, and in the stator winding head, the stator winding extends out of the stacking section, for example, in a bow shape. In addition, the machine housing includes a first cooling system based on a first cooling fluid surrounding the stator lamination stack. In addition, the present invention relates to a vehicle driven by an electric machine of the above type. Background Art

[0002] Electric machines and vehicles of the above type are generally known. Usually, electric machines must be cooled, lubricated, and protected against oxidation. However, these different functions have very specific requirements, and it is difficult to provide these functions at a high level simultaneously. Therefore, trade - offs are usually made between the functions, which also means that the potential of the electric machine is usually not fully utilized. Summary of the Invention

[0003] Therefore, an object of the present invention is to provide an improved electric machine and an improved vehicle. In particular, a solution should be proposed that allows for the cooling and lubrication of the electric machine and avoids oxidation inside the electric machine.

[0004] The object of the present invention is solved by an electric machine as disclosed in the opening paragraph, where the machine housing further includes a separate second cooling system based on a separate second cooling fluid, and the separate second cooling system includes nozzles or holes that point to at least one of the stator winding heads. The nozzles or holes can point to only one stator winding head or to two stator winding heads.

[0005] The object of the present invention is also solved by a vehicle that includes an electric machine of the above type, and the electric machine is designed to propel the vehicle. For example, the first cooling system of the electric machine can be part of a first cooling circuit of the vehicle, and the second cooling system can be part of a separate second cooling circuit of the vehicle.

[0006] By using the proposed measures, it is possible to provide the functions of cooling, lubrication and oxidation protection simultaneously at a very high level. Generally, the first cooling fluid may be water-based, while the second cooling fluid may be oil-based. In this way, on the one hand, efficient cooling can be achieved in the stacked section of the stator, and on the other hand, in addition, the stator winding heads can be cooled and lubricant can be introduced into the interior of the motor. It should be noted here that the heat capacity of the water-based cooling fluid is much higher than that of the oil. Therefore, in this case, the cooling power of the first cooling system is also higher than that of the second cooling system. By the proposed measures, unwanted oxidation can also be avoided inside the motor. Therefore, the full potential of the motor can be utilized.

[0007] Further advantageous embodiments are disclosed in the claims and the description and the drawings.

[0008] In one embodiment, the motor housing may include a tubular section surrounding the stator and an end section enclosing the tubular section, wherein the motor housing includes in the tubular section:

[0009] an inner housing part,

[0010] an outer housing part, the outer housing part being located radially outside the inner housing part,

[0011] the first cooling channels of the first cooling system, wherein the first cooling channels are formed between the inner housing part and the outer housing part, and

[0012] the second cooling channels of the second cooling system and a pipe section nozzle or hole hydraulically connected to the second cooling channels, the pipe section nozzle or hole pointing to at least one of the stator winding heads, wherein the second cooling channels are also formed between the inner housing part and the outer housing part.

[0013] In this way, the pipe section nozzle or hole points radially inwards and sprays the second cooling fluid onto the radial outside of the (multiple) stator winding heads.

[0014] Preferably, the second cooling system may include cooling channels and end section nozzles or holes hydraulically connected to the cooling channels in at least one of the end sections, the end section nozzles or holes pointing to at least one of the stator winding heads. In this way, end section nozzles or holes are provided which point axially inwards and spray the second cooling fluid onto the front faces of the (multiple) stator winding heads. Therefore, cooling can be even more improved.

[0015] In a further advantageous embodiment of the electric machine, the second cooling system may include an axial central shaft bore in the rotor shaft and a rotor shaft nozzle or hole hydraulically connected to the axial central shaft bore, the rotor shaft nozzle or hole pointing to at least one of the stator winding heads. Thus, the rotor shaft nozzle or hole points radially outwards and sprays the second cooling fluid onto the radially inner side of the (plural) stator winding heads, wherein the rotation of the rotor supports the distribution of the second cooling fluid. Additionally, the second cooling system can also be used for cooling the rotor.

[0016] Generally,

[0017] The course of the first cooling channel may have at least an axial component and may enclose an angle of 0° ≤ α < 90° with the rotor axis when observed in the radial direction, and

[0018] When observed in the radial direction, the course of the second cooling channel may enclose an angle of 90° ≥ β > α with the rotor axis, where in particular β = 90°.

[0019] In other words, the first cooling channel extends axially or helically, and the second channel particularly forms a closed loop.

[0020] Furthermore, in one embodiment of the electric machine, one of the end sections and the tubular section are a single component, and both form a can-shaped section, while in another embodiment, the tubular section and the end section are separate components. This means that for the first variant, only one additional bearing shield is required, while for the second variant, two bearing shields are required. Description of the Drawings

[0021] The present invention will now be described in more detail below with reference to specific embodiments, however the present invention is not limited to these specific embodiments.

[0022] Figure 1 A half-sectional view of a first exemplary electric machine is shown;

[0023] Figure 2 Similar to Figure 1 but with an additional front-side nozzle;

[0024] Figure 3 Similar to Figure 2 but having an additional nozzle in the rotor shaft;

[0025] Figure 4 A detailed perspective view of an exemplary inner housing component as seen from the side;

[0026] Figure 5 is the inner housing component of Figure 4 viewed more from the front and the rear.

[0027] Figure 6Shows a schematic diagram of an electric vehicle. Detailed implementation

[0028] Generally, the same or similar parts are denoted by the same / similar names and reference numerals. The features disclosed in the specification apply to the components with the same / similar names and reference numerals. The indicated orientations and relative positions are related to the associated figures.

[0029] Figure 1 Shows a half-sectional view of the electric machine 1, which includes a machine housing 2a, a stator 3 fixedly arranged in the machine housing 2a, a rotor shaft 4, and a rotor 5 mounted on the rotor shaft 4. The rotor 5 is rotatably arranged in the machine housing 2a about a rotor axis A through the rotor shaft 4. The stator 3 includes a stator lamination stack 6 and a stator winding 7 arranged therein. The rotor 5 includes a rotor lamination stack 8, in which a rotor winding or rotor magnets may be arranged (not shown).

[0030] The stator winding 7 includes a stacked section B and stator winding heads C, C'. In the stacked section B, the stator winding 7 extends within the stator lamination stack 6. At the stator winding heads C, C', the stator winding 7 extends out of the stacked section B and may have an arcuate shape. In addition, the electric machine 1 in the machine housing 2a includes a first cooling system 9 based on a first cooling fluid surrounding the stator lamination stack 6, and separate second cooling systems 10, 10' based on a separate second cooling fluid. The separate second cooling systems 10, 10' extend over the entire circumference of the machine housing 2a. The separate second cooling systems 10, 10' include nozzles or holes 11, 11' that point towards the two stator winding heads C, C'. In Figure 1 the example, the nozzles or holes 11, 11' point radially inwards towards the two stator winding heads C, C'. The injection jets 12 represent the second cooling fluid being sprayed on the radially outer sides of the stator winding heads C, C'. Advantageously, the nozzles or holes 11, 11' are distributed over the entire circumference of the machine housing 2a, particularly the inner housing 13a.

[0031] Specifically, the machine housing 2a includes an inner housing member 13a and an outer housing member 14a, and the outer housing member 14a is located radially outside the inner housing member 13a. In addition, the machine housing 2a includes a bearing shield 15, in which bearings 16a, 16b for supporting the rotor shaft 4 are arranged in the outer housing member 14a and the bearing shield 15. The machine housing 2a further includes a first cooling channel 17 and second cooling channels 18, 18'. The first cooling channel 17 is part of the first cooling system 9 and is formed between the inner housing member 13a and the outer housing member 14a. The second cooling channels 18, 18' are part of the second cooling systems 10, 10' and are also formed between the inner housing member 13a and the outer housing member 14a. Additionally, the second cooling channels 18, 18' are hydraulically connected to nozzles or holes 11, 11'.

[0032] In Figure 1 the example of, there are two second cooling channels 18, 18' with connected nozzles or holes 11, 11', and the nozzles or holes 11, 11' point to two stator winding heads C, C'. However, it can also be the case that there is only one cooling channel 18, 18' with a connected nozzle or hole 11, 11' that points to only one of the stator winding heads C, C'.

[0033] Generally, the first cooling fluid can be water-based, while the second cooling fluid can be oil-based. In this way, on the one hand, efficient cooling can be achieved in the stacked section B of the stator 5, and on the other hand, in addition, the stator winding heads C, C' can be cooled and lubricant can be brought into the interior of the electric machine 1. It should be noted here that the heat capacity of the water-based cooling fluid is much higher than that of the oil. By the proposed measures, unwanted oxidation can also be avoided inside the electric machine 1.

[0034] Figure 2 Now another example of the electric machine 1b is shown, which is similar to Figure 1 the electric machine 1a shown. In contrast, the second cooling system 10 further includes a cooling channel 18'' and an end-section nozzle or hole 19 hydraulically connected to the cooling channel 18'', and the end-section nozzle or hole 19 points to at least one of the stator winding heads C, C'. Specifically, the end-section nozzle or hole 19 points axially inward and sprays the second cooling fluid on the front face of the stator winding head C.

[0035] Generally, the machine housings 2a, 2b of the electric machines 1a, 1b can include a tubular section D surrounding the stator 3 and end sections E1, E2 closing the tubular section D, where the inner housing member 13a and the outer housing member 14a are preferably part of the tubular section D, as Figure 2 shown. In Figure 2In the example, the cooling channels 18” are arranged only in the end section E1. However, additional cooling channels 18” may also be present in the end section E2.

[0036] In Figure 1 and Figure 2 In the example, one of the end sections E1, E2 (end section E1) and the tubular section D are a single component, and both form a can-shaped section. However, the tubular section D and the end sections E1, E2 can be separate components, which means that the electric machine 1 can include two bearing shields 15.

[0037] Figure 3 Now, another example of the electric machine 1c is shown, which is similar to Figure 2 the electric machine 1b shown in

[0038] Figure 4 and Figure 5 Now, different perspective views of the inner housing component 13d are shown, Figure 4 shown from the side, Figure 5 more from the front. As can be seen especially in Figure 4 the route of the first cooling channel 17 preferably has at least an axial component and can enclose an angle of 0° ≤ α < 90° with the rotor axis A when observed in the radial direction. In addition, when observed in the radial direction, the routes of the second cooling channels 18, 18’ can enclose an angle of 90° ≥ β > α° with the rotor axis A. In particular, β can be 90°. In other words, this means that the first cooling channel 17 can extend axially or helically, and the second channels 18, 18’ can in particular form a closed loop.

[0039] Advantageously, the inner housing 13d includes a radially extending first flange at one axial end. The first flange includes an axial outlet (not shown) for the second cooling fluid. At the other axial end, the inner housing 13d includes an external radially extending portion (i.e., the radially extending portion extends away from the axis from the inner housing). The radially extending portion is designed to contact a corresponding portion of another flange and / or the outer housing 14a.

[0040] Figure 6Finally, an electric vehicle 22 with an electric machine 1 of the type defined above is shown, which electric machine 1 is arranged to propel the electric vehicle 25. Specifically, the electric machine 1 is coupled to a gearbox 23, a side shaft 24, and finally to wheels 25. The electric machine 1 can be arranged to permanently power the electric vehicle 22 in a pure electric vehicle, or to intermittently power the electric vehicle 22 in combination with an internal combustion engine in a hybrid vehicle, for example.

[0041] In addition, the electric vehicle 22 includes a first pump 26, a first cooler 27, a second pump 28, and a second cooler 29. The first pump 26, the first cooler 27, and the first cooling system 9 of the electric machine 1 are part of a first cooling circuit 30 of the vehicle 22. The second pump 28, the second cooler 29, and the second cooling systems 10, 10' of the electric machine 1 are part of a second cooling circuit 31 of the vehicle 22. In this way, the first cooling fluid and the second cooling fluid can work independently.

[0042] It should also be noted that the present invention is not limited to the embodiments disclosed above, but combinations of different variants are possible. In fact, the electric machines 1, 1a..1c and the electric vehicle 22 can have more or fewer components than shown in the figures. It should also be noted that the electric machines 1, 1a..1c and the electric vehicle 22 or their components are not necessarily drawn to scale in the drawings. In addition, the description may include subject matter of additional independent inventions.

[0043] Finally, it should be noted that the term "comprising" does not exclude other elements, and the use of the article "a" or "an" does not exclude a plurality. Elements described in connection with different embodiments can also be combined. It should also be noted that the reference signs in the claims should not be construed as limiting the scope of the claims.

[0044] List of reference signs

[0045] 1, 1a…1c Electric machine

[0046] 2a…2c Machine housing

[0047] 3 Stator

[0048] 4 Rotor shaft

[0049] 5 Rotor

[0050] 6 Stator lamination stack

[0051] 7 Stator winding

[0052] 8 Rotor lamination stack

[0053] 9 First cooling system

[0054] 10, 10’ Second cooling system

[0055] 11, 11’ Pipe section nozzle / hole

[0056] 12 injection jet

[0057] 13a…13d inner housing components

[0058] 14a…14c outer housing components

[0059] 15 bearing shield

[0060] 16a, 16b roller bearings

[0061] 17 first cooling channel

[0062] 18..18” second cooling channel

[0063] 19 end section nozzle / hole

[0064] 20 central shaft hole

[0065] 21, 21’ rotor shaft nozzle / hole

[0066] 22 vehicle

[0067] 23 gearbox

[0068] 24 side shaft

[0069] 25 wheel

[0070] 26 first pump

[0071] 27 first cooler

[0072] 28 second pump

[0073] 29 second cooler

[0074] 30 first cooling circuit

[0075] 31 second cooling circuit

[0076] A rotor axis

[0077] B stacking section

[0078] C, C’ stator winding heads

[0079] D tubular section

[0080] E1, E2 end sections

[0081] α Angle between the route of the first cooling channel and the rotor axis

[0082] β Angle between the route of the second cooling channel and the rotor axis

Claims

1. An electric motor (1, 1a..1c), comprising a motor housing (2a..2c), a stator (3) fixedly arranged in the motor housing (2a..2c), a rotor shaft (4) and a rotor (5) mounted on the rotor shaft (4), wherein the rotor (5) is rotatably arranged in the motor housing (2a..2c) around a rotor axis (A) via the rotor shaft (4), in, The stator (3) comprises a stator lamination stack (6) and a stator winding (7) arranged on the stator lamination stack. The stator winding (7) comprises a stacking section (B) and a stator winding head (C, C'), wherein the stator winding extends within the stator lamination stack (6) in the stacking section (B) and the stator winding head (C, C') extends out of the stacking section (B), wherein the machine housing (2a..2c) comprises a first cooling system (9) based on a first cooling fluid around the stator lamination stack (6), It is characterized in that The machine housing (2a..2c) comprises a separate second cooling system (10, 10') based on a separate second cooling fluid, wherein the separate second cooling system (10, 10') comprises nozzles or holes (11, 11') directed towards at least one of the stator winding heads (C, C').

2. The electric machine (1, 1a..1c) according to claim 1, characterized in that The first cooling fluid is water based and the second cooling fluid is oil based.

3. The electric machine (1, 1a..1c) according to claim 1 or 2, characterized in that The nozzles or holes (11, 11') are directed towards the two stator winding heads (C, C').

4. The electric machine (1, 1a..1c) according to claims 1 to 3, characterized in that The machine housing (2a..2c) comprises a tubular section (D) surrounding the stator (3) and end sections (E1, E2) closing the tubular section (D), wherein the machine housing (2a..2c) comprises in the tubular section (D) Inner casing parts (13a..13d), An outer shell component (14a...14c) is located radially outside the inner shell component (13a...13d), a first cooling channel (17) of the first cooling system (9), wherein the first cooling channel (17) is formed between the inner housing part (13a ... 13d) and the outer housing part (14a ... 14c), and A second cooling channel (18, 18') of the second cooling system (10, 10') and a pipe section nozzle or hole (11, 11') hydraulically connected to the second cooling channel (18, 18'), the pipe section nozzle or hole (11, 11') pointing toward at least one of the stator winding heads (C, C'), wherein the second cooling channel (18, 18') is also formed between the inner housing part (13a...13d) and the outer housing part (14a...14c).

5. The electric machine (1, 1a..1c) according to claim 4, characterized in that The path of the first cooling channel (17) has at least an axial component and, viewed in the radial direction, encloses an angle of 0° α < 90° with the rotor axis (A), Viewed in the radial direction, the course of the second cooling channel (18, 18') encloses an angle of 90°3β>a with the rotor axis (A), wherein in particular β=90°.

6. The electric machine (1, 1a..1c) according to claim 4 or 5, characterized in that The second cooling system (10, 10') comprises, in at least one of the end segments (E1, E2), a cooling channel (18") and an end segment nozzle or hole (19) hydraulically connected to the cooling channel (18"), the end segment nozzle or hole (19) being directed towards at least one of the stator winding heads (C, C').

7. The electric machine (1, 1a..1c) according to any one of claims 4 to 6, characterized in that One of the end sections (E1, E2) is a single component with the tubular section (D), and the two form a pot-shaped section, or The tubular section (D) and the end sections (E1 , E2) are separate components.

8. The electric machine (1, 1a..1c) according to any one of claims 1 to 7, characterized in that The second cooling system (10, 10') comprises an axial central shaft hole (20) in the rotor shaft (4) and a rotor shaft nozzle or hole (21, 21') hydraulically connected to the axial central shaft hole (20), the rotor shaft nozzle or hole (21, 21') being directed towards at least one of the stator winding heads (C, C').

9. A vehicle (22) driven by an electric machine (1, 1a..1c) according to any one of claims 1 to 8.

10. The vehicle (22) according to claim 9, characterized in that The first cooling system (9) is part of a first cooling circuit (30) of the vehicle (22), and the second cooling system (10, 10') is part of a separate second cooling circuit (31) of the vehicle (22).

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