Electric motor unit comprising an electric motor and a heat exchanger

Abstract

Electric motor unit (9), preferably for a vehicle, in particular an aircraft, comprising an electric motor (10) and a heat exchanger (11), wherein the electric motor (10) and the heat exchanger (11) are housed in a common housing.

Description

[0001] MEISSNER BOLTE

[0002] PO Box 860624

[0003] 81633 Munich

[0004] Additive | Drives GmbH January 29, 2026 Pforzheimer Str. 7A M / ADID-042-PC 01189 Dresden

[0005] Electric motor unit comprising an electric motor and a heat exchanger

[0006] Description

[0007] The invention relates to an electric motor unit, preferably for a vehicle, in particular an aircraft, comprising an electric motor and a heat exchanger.

[0008] Active or passive cooling of electric motors is now standard practice in automotive engineering and other high-speed or high-frequency applications. These motors inherently generate a certain amount of thermal energy, making cooling necessary for efficient operation. It is generally advantageous to apply the cooling directly to the conductor itself, as this significantly increases cooling efficiency and allows for a more compact design.

[0009] Typically, the conductors are inserted into a pre-machined groove in a stator core, preferably via cooling channels within or near the groove. It is generally known from the prior art to provide cooling channels along the conductors in a stator.

[0010] Overall, current state-of-the-art solutions are still perceived as relatively complex. In particular, their space requirements are considered comparatively high.

[0011] The particular object of the invention is to propose an electric motor unit through which efficient cooling can be achieved in a simple and, in particular, space-saving manner.

[0012] This problem is solved in particular by the features of claim 1. Meissner Bolte 2 M / ADID-042-PC

[0013] In particular, the problem is solved by an electric motor unit, preferably for a vehicle, especially an aircraft, preferably an airplane and / or helicopter, or a land vehicle, for example a car or truck, especially a racing car, or a watercraft. The electric motor unit comprises an electric motor and a heat exchanger, wherein the electric motor and heat exchanger are housed in a common casing.

[0014] One idea is to house the electric motor and heat exchanger in a common unit, especially within a common housing.

[0015] Especially when the heat exchanger is arranged around the electric motor, the electric motor can be housed in an inner casing (with the heat exchanger then located outside this inner casing, at least partially). However, such an inner casing can also be omitted in some designs.

[0016] A common housing is understood to mean, in particular, that the electric motor and heat exchanger are arranged within a volume defined by a housing. The housing may have at least one opening (for example, for fluid passage). However, all openings, if any, should preferably together define less than 40%, more preferably less than 20%, and possibly less than 10% of the housing's outer surface.

[0017] The common housing is preferably dimensioned such that it is (at least substantially) filled by the electric motor and the heat exchanger. The electric motor and heat exchanger can preferably occupy at least 50%, and optionally at least 80%, of the internal volume of the common housing.

[0018] The heat exchanger is preferably arranged around the electric motor at least in sections (possibly completely or at least over at least 60% or at least 90% of a spherical surface of the electric motor or the optional separate (inner) housing of the electric motor).

[0019] A diameter (= distance between the pair of points of the respective referenced element that has the greatest distance between all pairs of points of the respective element) of the common housing is preferably at least 1 time, optionally at least 1.2 times and / or at most 3 times, preferably at most 2 times as large as a diameter of the electric motor and / or a diameter of the optional separate (inner) housing of the electric motor. Meissner Bolte 3 M / ADID-042-PC

[0020] Current systems (comprising an electric motor and its cooling system) utilize a multitude of components, the individual manufacturing and connection of which determine the overall system. This often increases the installation space and weight due to media routing and / or their seals (or screw connections). Furthermore, each connection must undergo individual quality control. The safety factors in the connection technology, which must be considered during the design phase, also increase the system weight. In contrast, the electric motor unit presented here can achieve weight savings and a reduction in system size. Manufacturing can potentially be carried out in a single (partially or fully additive) production step (e.g., partially or fully via laser sintering), including the production of the electric motor or at least one / part of the motor housing (especially the separate housing mentioned above) and / or the heat exchanger and / or other components.This includes media routing. The manufacturing effort for individual components is then reduced. Testing and qualification efforts are also reduced. A stable unit can be realized with simple means.

[0021] The present electric motor unit is particularly advantageous in aviation, motorsports, robotics or the automotive sector.

[0022] Preferably, the heat exchanger and / or at least one fluid guide thereof and / or at least one connection line for at least one fluid, in particular a cooling fluid, is partially or completely integrated into a housing wall of the common housing. Particularly preferably, the housing wall, on the one hand, and the heat exchanger and / or at least one fluid guide thereof and / or at least one connection line for at least one fluid, in particular a cooling fluid, on the other hand, form a single-piece, preferably monolithic, and / or additively manufactured (preferably by laser sintering and / or laser melting) unit.

[0023] Alternatively or (partially) additionally, the heat exchanger can be formed within the housing wall. Specifically, the heat exchanger and / or at least one fluid channel thereof and / or at least one connection line for at least one fluid, in particular a cooling fluid, can be formed partially or completely within the housing wall.

[0024] Preferably, the heat exchanger is configured to cool a cooling fluid using air. Specifically, the heat exchanger can be an air-to-fluid, in particular air-to-liquid, or optionally air-to-water heat exchanger. Specifically, the heat exchanger can have a plurality, for example, at least five, preferably at least 100, optionally at least 400, and / or at most 10,000 air channels through which air (for example, Meissner Bolte 4 M / ADID-042-PC) flows.

[0025] (Outside air) can flow. Such a heat exchanger is preferably configured for passive cooling, in which the heat generated by the electric motor is dissipated by the supply of (outside) air. At least one cooling fluid channel can be provided for the cooling fluid, which can extend into the electric motor. In embodiments, several cooling fluid channels can also be provided, for example, at least two or at least five and / or at most 100.

[0026] Several cooling fluid channels and / or several air channels can, for example, run parallel to each other (at least partially and / or at least in sections).

[0027] Insofar as a cooling fluid is mentioned above and below, this may in particular be a cooling fluid, preferably comprising water and / or oil.

[0028] Alternatively or additionally, the heat exchanger can be configured to cool a cooling fluid by means of a refrigerant circuit. The refrigerant circuit can include a circulation pump and / or a compressor. The refrigerant circuit, in particular (at least) a circulation pump and / or a compressor thereof, is preferably at least partially integrated into the (common) housing. In such embodiments, the refrigerant circuit or at least components thereof (such as a circulation pump or a compressor) can also be arranged outside the housing. In general, the heat exchanger can be configured for active cooling (i.e., cooling in which a working medium is actively cooled and heat, which is in turn absorbed by the cooling fluid, is carried away from the electric motor). Alternatively or additionally, the heat exchanger can be configured to enable phase-change cooling and / or evaporative cooling.

[0029] Specifically, the electric motor unit or heat exchanger can be configured to perform phase-change cooling or evaporative cooling in such a way that heat is dissipated through the evaporation of a liquid. For this purpose, an (electrically insulating) coolant (cooling fluid) can be used, which preferably evaporates in or on the windings (copper coils) of the electric motor to dissipate the generated heat. The heat of vaporization of the coolant can then be used for particularly effective heat removal.

[0030] Unlike conventional fluid cooling systems (or liquid cooling systems, e.g., water jackets), here the coolant can be brought into direct contact with the heat-generating component (the electric motor). This can be thermally Meissner Bolte 5 M / ADID-042-PC

[0031] This reduces resistance and enables comparatively good temperature control. A so-called wicking structure (capillary structure) can promote liquid flow and evaporation.

[0032] Specifically, the coolant (cooling fluid) can evaporate in the area of ​​the electric motor and / or within the electric motor itself when it absorbs heat from a component of the electric motor. The vapor can be conveyed through a system to a condenser. In the condenser, the vapor is cooled, causing it to revert to its liquid phase. The condenser can be implemented using the heat exchanger (as described above and below). The liquid coolant can be returned to the electric motor or the heat source and / or by capillary action.

[0033] Preferably, the electric motor unit comprises a pump, in particular a circulation pump, and / or a compressor and / or an evaporator. The components mentioned here can be arranged individually or in combination within (or outside) the (common) housing. Specifically, a circulation pump can be provided for circulating the cooling fluid. Alternatively or additionally, a circulation pump (particularly in active cooling, for example comprising a compressor) can be provided for circulating a refrigerant.

[0034] The electric motor unit can have at least one capillary structure (wicking structure) and / or at least one spray nozzle for supplying liquid to be evaporated to a surface (of the electric motor) to be cooled. Preferably, the heat exchanger is arranged at least partially, and more preferably completely, around the electric motor, particularly concentrically. This allows for a particularly compact design.

[0035] The heat exchanger preferably has at least one cooling fluid channel, which preferably, and in particular concentrically, runs around the electric motor. Alternatively or additionally, the heat exchanger can have at least one cooling fluid channel that is annular.

[0036] Specifically, the heat exchanger can have a multitude of cooling fluid channels (which can be connected in series or parallel), preferably each running concentrically around the electric motor. The multiple cooling fluid channels can run at successively increasing distances from a common center or be formed by rings with successively larger diameters. Meissner Bolte 6 M / ADID-042-PC

[0037] exhibit. For example, at least two, at least three, or at least five and / or 10 of the (ring-shaped) cooling fluid channels may be provided.

[0038] At least one channel for a refrigerant and / or air (especially outside air) preferably runs in an axial direction (relative to an electric motor axis).

[0039] In particular, if such channels are air ducts, at least 10, at least 50, or at least 200 such channels may be provided.

[0040] The heat exchanger can have a plurality of cooling fins (for example, at least five, or at least 50, or at least 500, and / or at most 100,000). Alternatively or additionally, the electric motor unit can have two (or more), preferably concentric, cooling channel sections, which are further preferably connected to each other by at least a portion of the plurality of cooling fins. This allows for particularly effective heat dissipation.

[0041] Preferably, the electric motor unit includes a connection (a connection device) for a, possibly one-time, filling with cooling fluid.

[0042] The above-mentioned problem is solved in particular by a method for cooling an electric motor unit (as described above and / or below), wherein heat is removed from the electric motor, in particular by a cooling fluid, preferably liquid, wherein the cooling fluid optionally undergoes a phase transition from liquid to gaseous (or alternatively does not undergo such a phase transition).

[0043] The above-mentioned task is further solved in particular by a vehicle, especially an aircraft and / or racing car, comprising an electric motor unit (as described above and / or below).

[0044] The heat exchanger can preferably be manufactured additively (at least partially), in particular by laser sintering and / or laser melting. In particular, at least cooling fins and / or cooling fluid channels and / or refrigerant channels and / or air ducts can be additively manufactured.

[0045] The wall thickness of the heat exchanger (for example, in the area of ​​one or more fins or a wall for guiding a cooling fluid, air, or refrigerant) can be at most 1000 pm, preferably at most 120 pm and / or Meissner Bolte 7 M / ADID-042-PC

[0046] The surface area should be at least 20 µm, or possibly at least 50 µm. This allows for a comparatively large cooling surface with minimal material usage.

[0047] Cooling fins preferably extend from one cooling fluid channel to an adjacent cooling fluid channel (the two adjacent cooling fluid channels being directly connected, if necessary by material bonding, for example by additive manufacturing or welding).

[0048] Further process characteristics arise from the description of the electric motor unit, whereby functional characteristics and / or purpose specifications can be implemented as concrete process characteristics. For example, the process can specifically involve evaporation and / or heat input or output.

[0049] An axis of rotation and / or symmetry of a compressor and / or an axis of rotation and / or symmetry of a pump can run parallel to an axis of rotation and / or symmetry of the electric motor, in particular coincide with it.

[0050] The invention is described below with regard to further details, features, and advantages, which are explained in more detail with reference to the figures. The described features and combinations of features, as shown in the figures below and described with reference to them, can be implemented not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention.

[0051] This shows:

[0052] Fig. 1 shows a schematic representation of an electric motor with an attached cooling system;

[0053] Fig. 2 shows an oblique view of an electric motor unit according to the invention, and

[0054] Fig. 3 shows a schematic sectional view of the electric motor unit according to Fig. 2.

[0055] In the following description, the same reference numbers are used for identical and equivalently functioning parts. Meissner Bolte 8 M / ADID-042-PC

[0056] Figure 1 shows a schematic representation of an electric motor with an attached cooling system. In principle, the system according to the invention can also comprise the components shown there.

[0057] The system initially comprises an electric motor 10, the heat from which is dissipated via a heat exchanger 11. The heat exchanger 11 is connected to a fluid reservoir 13 via an optional filter 12. A cooling fluid can be supplied to or circulated through the electric motor 10 via a pump 14. The electric motor 10 can be powered by a power supply 15 (battery). The electric motor 10 can, for example, drive a propeller 16. Furthermore, an inverter 17 can be provided to enable inverter cooling (in series or parallel).

[0058] According to the invention, the electric motor 10, heat exchanger 11, fluid reservoir 13 and pump 14 can preferably be housed in a (common) housing, wherein preferably at least the heat exchanger is integrated (at least partially, possibly completely) in a housing wall.

[0059] In Fig. 1, PCD stands for electrical (direct current) power, PAC for electrical (alternating current) power, PM for mechanical power, the Greek thetal for inlet temperature, the Greek theta2 for outlet temperature, V (with dot) for volume flow rate, Greek delta p for pressure drop, and the arrows 22 for heat.

[0060] Fluid conditioning can take place in the heat exchanger. The pump can be powered via battery 15.

[0061] Optionally, inverter cooling (in series or parallel) can be implemented (see dotted lines leading into and out of the inverter 17).

[0062] Fluid properties can be adjusted and / or monitored with regard to state of matter, density and / or specific heat capacity.

[0063] Figure 2 shows an electric motor unit 9. This unit comprises, in a concentric arrangement, an electric motor 10 and a heat exchanger 11 arranged around the electric motor 10. The heat exchanger is located in a housing 21, preferably integrated into a housing wall 23. The heat exchanger 11 preferably comprises a plurality of (concentric) cooling fluid channels 20, which may be connected to one another by fins (not shown) (which may extend radially). Meissner Bolte 9 M / ADID-042-PC

[0064] Fig. 3 shows a schematic sectional view of the electric motor unit according to Fig. 2. A connecting line 24 (for a one-time filling with a cooling fluid) is particularly visible, which is preferably integrally formed with the housing wall 23. Furthermore, (concentric) cooling fluid channels 25 are visible (schematically represented as lines; hollow inside).

[0065] Waste heat, e.g. from a groove area, can be removed via a cooling fluid channel 26 and distributed in the heat exchanger.

[0066] The motor could be a high-performance electric motor.

[0067] It should be noted here that all parts described above, considered individually and in any combination, especially the details shown in the drawings, are claimed as essential to the invention. Modifications to this are familiar to those skilled in the art.

[0068] Furthermore, it is noted that the broadest possible scope of protection is sought. Therefore, the disclosure contained in the claims can also be specified by features that are described by further features (even if these further features are not necessarily included). It is explicitly pointed out that parentheses and the term "in particular" are intended to emphasize the optionality of features in the respective context (which does not imply that a feature is mandatory in the corresponding context without such indication). The term "element" can denote a coherent structure, which in turn may be connected to at least one other structure (to form a potentially monolithic and / or internally immobile overall structure) (or may be distinct from all other structures).

[0069] Reference symbol list

[0070] 9 Electric motor unit

[0071] 10 Electric motor

[0072] 11 heat exchangers

[0073] 12 filters

[0074] 13 Fluid reservoir

[0075] 14 Pump

[0076] 15 Power supply (battery)

[0077] 16 propellersMeissner Bolte 10 M / ADID-042-PC

[0078] 17 Inverter

[0079] 20 cooling fluid channels 21 housing

[0080] 22 Arrow

[0081] 23 Housing wall 24 Connection cable 25 Cooling fluid channel 26 Cooling fluid channel

Claims

MEISSNER i ■ PO Box 860624 81633 Munich Additive | Drives GmbH January 29, 2026 Pforzheimer Str. 7A M / ADID-042-PC 01189 Dresden Electric motor unit comprising an electric motor and a heat exchanger Claims 1. Electric motor unit (9), preferably for a vehicle, in particular an aircraft, comprising an electric motor (10) and a heat exchanger (11), wherein the electric motor (10) and the heat exchanger (11) are housed in a common casing.

2. Electric motor unit (9) according to claim 1, wherein the heat exchanger (11), preferably at least one fluid guide thereof, and / or at least one connecting line for at least one fluid, in particular a cooling fluid, is integrated sectionally or completely into a housing wall of the common housing.

3. Electric motor unit (9) according to claim 1 or 2, wherein the heat exchanger (11) is configured to cool a / the cooling fluid by means of air.

4. Electric motor unit (9) according to one of the preceding claims, wherein the heat exchanger (11) is configured to cool a / the cooling fluid by means of a refrigerant circuit, wherein the refrigerant circuit, in particular a circulation pump (14) and / or a compressor thereof, is preferably at least partially integrated into the housing.

5. Electric motor unit (9) according to one of the preceding claims, wherein the heat exchanger (11) is configured to enable phase-change cooling and / or evaporative cooling. Meissner Bolte 2 M / ADID-042-PC 6. Electric motor unit (9) according to one of the preceding claims, comprising a pump (14), in particular a circulation pump (14), and / or a compressor and / or an evaporator.

7. Electric motor unit (9) according to one of the preceding claims, comprising at least one spray nozzle and / or at least one capillary structure for supplying liquid to be evaporated to a surface to be cooled.

8. Electric motor unit (9) according to one of the preceding claims, wherein the heat exchanger (11) is arranged, in particular concentrically, around the electric motor (10).

9. Electric motor unit (9) according to one of the preceding claims, wherein the heat exchanger (11) has at least one cooling fluid channel (20) which runs concentrically around the electric motor (10) and / or is annular.

10. Electric motor unit (9) according to one of the preceding claims, wherein the heat exchanger (11) has a plurality of cooling fins and / or has two or more, preferably concentric, cooling channel sections, which are further preferably connected to each other by at least a part of the plurality of cooling fins.

11. Electric motor unit (9) according to one of the preceding claims, comprising a connection, in particular comprising a connection line, for a, possibly one-time, cooling fluid filling.

12. Method for cooling an electric motor unit (9) according to one of the preceding claims, wherein heat is removed from the electric motor (10), in particular by a cooling fluid, preferably liquid, wherein the cooling fluid optionally undergoes a phase transition from liquid to gaseous, or not.

13. Vehicle, in particular aircraft and / or racing car, comprising an electric motor unit (9) according to any of the preceding claims.

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