Electric machine with cooled busbars

Abstract

The invention relates to an electric machine (1), comprising a rotor (2) and a stator (3), the rotor (2) and the stator (3) being at least partially arranged in a machine housing (4), and comprising a cooling jacket (5) for cooling the stator (3), a plurality of mutually parallel first cooling channels (6) extending in particular in the axial direction with respect to the stator axis extending through the cooling jacket (5) for guiding a cooling medium, wherein the machine housing (4) comprises at least one bearing cover (7) connected to the cooling jacket (5) for supporting a rotor shaft (8) of the rotor (2), wherein a plurality of second cooling channels (9) are formed on the bearing cover (7), the plurality of second cooling channels (9) respectively connecting two, in particular adjacent, first cooling channels (6) 6) are flow-connected to each other, wherein the second cooling channel (9) and the first cooling channel (6) form a coolant path through the electric machine (1), the coolant path being in particular serpentine or snake-shaped, and wherein at least one busbar (10) extends at the bearing cover (7), the busbar (10) being electrically connected to the stator winding (14) of the stator (3), characterized in that the busbar (10) has a main section (11) and at least one cooling shoulder (12) extending from the main section (11), wherein the cooling shoulder (12) engages in a housing recess (13) of the bearing cover (7), the housing recess (13) being configured to be directly adjacent to one of the second cooling channels (9).

Description

Background Art

[0001] The invention relates to an electric machine, which in particular has a cooled busbar.

[0002] An electric motor is known from the prior art, for example from EP 1401089 A1. Common electric motors include a rotor and a stator, wherein the stator has a stator winding in which a magnetic field can be generated in order to drive the rotor. In order to energize the stator winding, there is a busbar, which heats up during operation due to its resistance. This heat is dissipated, for example, by a heat-conducting pad. Therefore, a part of the housing of the electric motor or the entire housing of the electric motor is usually made of a metal material, wherein the heat-conducting pad conducts heat from the busbar to the metal housing. Summary of the invention

[0003] The electric machine according to the invention enables effective cooling of the busbar. Optimized cooling can be achieved in particular when the housing of the electric machine is not made of a metallic material and / or is made of a material with poor thermal conductivity. The optimized cooling is achieved in that the busbar has a cooling shoulder that directly dissipates heat to a cooling channel, wherein a coolant can flow in the cooling channel. In this way, a safe and reliable heat dissipation of the busbar can be achieved.

[0004] The electric machine according to the invention has a rotor and a stator. The rotor and the stator are at least partially arranged in a machine housing. At least the stator has a stator winding. The rotor can be designed arbitrarily and is particularly designed to cooperate with the stator. As a result, the stator can drive the rotor.

[0005] The electric machine further comprises a cooling jacket for cooling the stator. A first cooling channel extends through the cooling jacket for guiding a cooling medium. The first cooling channel preferably extends parallel, in particular in an axial direction with respect to the stator axis. The cooling medium can be a heat-conducting fluid, for example water.

[0006] The machine housing includes a bearing cover. The bearing cover is connected to the cooling jacket. Advantageously, there can be multiple bearing covers connected to the cooling jacket. The rotating shaft of the rotor is supported on the bearing cover. The bearing cover also has a second cooling channel. The first cooling channel and the second cooling channel are particularly coupled for fluid communication, wherein each second cooling channel is flow-connected to two preferably adjacent first cooling channels. The motor can dissipate heat through the first cooling channel and the second cooling channel, and in particular the stator can be cooled through the cooling channel. The first cooling channel and the second cooling channel particularly constitute a continuous coolant path passing through the motor. Such a coolant path is preferably constructed in a meandering or serpentine manner.

[0007] At least one busbar extends on the bearing cover. The busbar is electrically connected to the stator winding of the stator. In this way, it is possible in particular to energize the stator winding via the busbar.

[0008] The busbar is provided with a retaining section and at least one cooling shoulder extending from the main section. The cooling shoulder is arranged in the machine housing so that the cooling shoulder engages in a housing recess of the bearing cover. The housing recess is configured to be directly adjacent to one of the second cooling channels. This enables heat transfer between the cooling medium flowing into the second cooling channel and the busbar, in particular the cooling shoulder of the busbar. As a result, the cooling shoulder can dissipate heat from the busbar in such a way that the heat of the busbar is transported away by the cooling medium.

[0009] This arrangement and construction of the busbars achieves that there is a large surface area for heat conduction from the busbars to the cooling medium. The busbars can be effectively cooled by this area. Thus, under the same electrical load, that is, under the same current, the cross-section of the busbars can be reduced. Thus, the cost of the motor can be reduced compared to the motor from the prior art. In addition, the reduction of the cross-section of the busbars can achieve weight savings. As an alternative, the effective cooling of the busbars can achieve that a larger current can flow when the cross-section of the busbars is the same. In addition, thermal pads such as those in the prior art are not necessary, thereby reducing the assembly costs and thus also reducing the assembly costs. The advantages of the effective cooling are achieved in particular by using the existing cooling circuit of the motor. The cooling circuit is used to cool the motor, especially the stator, and the winding heads of the stator are particularly preferred and thus already exist in the motor. As an alternative, there is such a feasible solution: a separate cooling circuit is constructed for the busbar cooling independently of the aforementioned circuit. Therefore, it is unnecessary to take special measures for heat conduction. In particular, cost-intensive hybrid structures, such as metal in plastic, can be avoided.

[0010] A preferred improvement of the present invention includes: the cooling jacket is a partial area of ​​the stator, in particular a partial area of ​​the stator laminated core, or a part of the machine housing that surrounds the stator in at least a partial area; the busbar has two cooling shoulders, and the two cooling shoulders are each arranged in its own housing recess, wherein the two housing recesses are constructed on both sides of one of the second cooling channels; a heat-conducting material, in particular a heat-conducting adhesive, is inserted between the cooling shoulder and the bearing cover; an electrically insulating material, in particular an electrically insulating adhesive and / or a protective varnish and / or an insert is inserted between the cooling shoulder and the bearing cover; the main area of ​​the busbar is constructed in one piece with the cooling shoulder of the busbar, wherein the busbar is in particular manufactured as a stamped and bent part; the main area of ​​the busbar and the busbar are The cooling shoulders of the busbars are separate elements that are connected to each other by a joining method; the main area and the cooling shoulders are connected by material locking, in particular brazing and / or welding, and / or force locking, in particular by a pressing connection, and / or form locking, in particular by a riveted connection; the stator winding is a three-phase winding, wherein there are three busbars, each of which is electrically connected to a phase of the stator winding; the cooling jacket and / or the bearing cover are made of a metal material and / or plastic; the cooling jacket is constructed in a hollow cylindrical shape, wherein the first cooling channel is arranged along the central axis of the hollow cylinder, and wherein the bearing cover closes the cooling jacket at the end face; the busbar with the cooling shoulder is injected into the bearing cover.

[0011] Advantageously, the cooling jacket is part of the stator or part of the machine housing. The cooling jacket can be configured in particular in the stator lamination stack. When the cooling jacket is part of the machine housing, the cooling jacket surrounds the stator at least partially, in particular completely. The cooling jacket surrounds the stator in particular in the circumferential direction around the axis of rotation of the electric machine. The stator is advantageously held by the cooling jacket.

[0012] Preferably, it is provided that the busbar has two cooling projections. Each cooling projection is arranged in its own housing recess of the bearing cap. One of the second cooling channels extends between the two housing recesses, which means that the two housing recesses are formed on both sides of one of the second cooling channels. By arranging the cooling projections on both sides of the cooling channel, the area over which heat is transferred from the busbar to the cooling medium can be increased. This provides an improved cooling efficiency. It is particularly advantageous if the two cooling projections extend parallel to one another.

[0013] Advantageously, a heat-conducting material is arranged between the cooling shoulder and the bearing cover. The heat-conducting material can be a heat-conducting adhesive in particular. This leads to a further improvement in the heat transfer between the busbar and the coolant flowing in the second cooling channel.

[0014] It is also advantageously provided that an electrically insulating material is inserted between the cooling shoulder and the bearing cap. In particular, it is an electrically insulating adhesive. It is particularly advantageous if the adhesive can be both electrically insulating and thermally conductive. If the adhesive is electrically insulating, it is possible, for example, to use housing parts made of metal, which allows for optimal heat conduction while at the same time minimizing the risk of short circuits via the busbars. As an alternative or in addition to the adhesive, the insulating material can also be a protective lacquer and / or an insert.

[0015] Advantageously, the main region of the busbar is formed integrally with the cooling shoulder of the busbar. It is particularly advantageous if the busbar is produced as a stamped and bent part. In this way, the busbar can be produced simply and cost-effectively, wherein the different regions, namely the main region and the cooling shoulder, can also be formed simply and inexpensively in this way.

[0016] In an alternative design, the main area and the cooling shoulder are separate elements. The cooling shoulder and the main area are connected to each other by a joining method. A joining method is particularly advantageous, which ensures an optimal heat transfer between the cooling shoulder and the main area. In this way, it is achieved that the cooling shoulder can be reliably used for heat dissipation of the main area and the entire busbar. By separately constructing the cooling shoulder and the main area and then joining these two components, the design of the busbar can be realized simply and cost-effectively in any manner and method. This provides increased flexibility in the layout and design of the busbar.

[0017] Preferably, it is provided that the main region and the cooling shoulder are connected in a material-locked manner. This is achieved in particular by welding and / or brazing. Similarly, the main region and the cooling shoulder can also be coupled by a force-locked connection. The force-locked connection can be achieved in particular by an extrusion connection. Finally, as an alternative or additional solution, it is provided that the main region and the cooling shoulder are connected in a form-locked manner. This can be achieved particularly advantageously by a riveted connection. All these different connection types enable a simple and cost-effective connection of the main region to the cooling shoulder, wherein heat transfer between the main region and the cooling shoulder can be achieved. This achieves that the cooling shoulder can dissipate heat from the main region and the entire busbar.

[0018] The stator winding is particularly advantageously a three-phase winding. As a result, there are three busbars, each of which is electrically connected to a phase of the stator winding. All of these busbars are designed as described above, i.e., all of them have a main region and at least one cooling shoulder. As a result, the busbars can be optimally cooled.

[0019] The cooling jacket and / or the bearing cover are preferably made of a metal material. As an alternative or in addition, the cooling jacket and the bearing cover can also be made of plastic. If a metal material is used, the thermal conductivity is improved. On the other hand, the components made of plastic allow for a flexible design and cost-effective production. When the bearing cover is made of plastic, as an alternative to the assembly solution of the busbar into the bearing cover, the busbar with the cooling shoulder can also be injected into the bearing cover.

[0020] The cooling jacket is advantageously shaped as a hollow cylinder. The first cooling channel is arranged along the central axis of the hollow cylinder, wherein the bearing cover closes the cooling jacket at the end face. In particular, an S-shaped extension of the cooling medium through the cooling jacket and the bearing cover can be achieved in this way.

[0021] It is particularly preferred if each cooling shoulder is designed in such a way that it extends parallel to the central axis of the rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the accompanying drawings:

[0023] Figure 1 is a schematic diagram of a motor according to an embodiment of the present invention;

[0024] Figure 2 is a schematic detailed view of the motor according to this embodiment of the present invention;

[0025] Figure 3 is a schematic cross-sectional view of a bearing cover of a machine housing of the electric machine;

[0026] Figure 4 is a schematic cross-sectional view of at least a partial region of the electric machine; and

[0027] Figure 5 is a schematic detailed view of a partial region of a busbar of the electric machine according to this exemplary embodiment of the invention. DETAILED DESCRIPTION

[0028] Figure 1 An electric machine 1 according to an embodiment of the invention is schematically shown. The electric machine 1 has a rotor 2 and a stator 3. The rotor 2 comprises a rotor shaft 8 which is rotatable about a central axis 100.

[0029] The rotor 2 can be driven by the stator 3. It is provided that the stator 3 can dissipate heat via cooling channels 6, 9. The cooling channels 6, 9 are arranged in the machine housing 4 of the electric machine 1.

[0030] The machine housing 4 thus comprises a cooling jacket 5 and at least one bearing cover 7 for supporting a rotor shaft 8, wherein Figure 1 Two bearing caps are shown in FIG. As an alternative, the cooling jacket 5 can also be part of the stator 3. The cooling jacket 5 is hollow cylindrical and additionally has a plurality of first cooling channels 6, each of which extends parallel to the central axis of the hollow cylinder. A fluid can flow in the first cooling channels, in particular for cooling the stator winding 14 (see FIG. Figure 4 ).

[0031] The bearing cover 7 also has a cooling channel, which is referred to below as a second cooling channel 9. The second cooling channel 9 connects two, for example, adjacent first cooling channels 6 to each other, so that the second cooling channel 9 and the first cooling channel 6 form a coolant path through the electric machine 1, which is designed, for example, in a meandering or serpentine shape. For this purpose, a flow deflector is formed in each of the second cooling channels 9, for example.

[0032] The rotor shaft 8 is supported on the bearing shields 7 via bearings 15. Each bearing shield 7 is mounted on the end side of a hollow cylindrical cooling jacket 5.

[0033] Figure 2 The schematic diagram shows the extension of three busbars 10. These busbars 10 are connected to the stator winding 14 (see Figure 4 ) electrical connection. Thus, the stator winding 14 can be energized by energizing the busbar 10. The busbar 10 is particularly arranged at the bearing cover 7.

[0034] Figure 3 A schematic detailed view of a bearing cover 7 is shown. The bearing cover 7 is shown to have housing recesses 13 on both sides of the second cooling channel 9. The cooling shoulder 12 extending from the main region 11 of the busbar 10 engages in the housing recess 13. In this case, it is provided in particular that the busbar is produced as a stamped and bent part. This allows the cooling shoulder 12 to be produced simply and with little effort. At the same time, an optimal heat transfer can be achieved between the main section 11 and the cooling shoulder 12.

[0035] The housing recess directly at one of the second cooling channels 9 and the arrangement of the cooling shoulder 12 on both sides of the second cooling channel 9 can create a large area, through which heat transfer from the busbar 10 to the coolant in the second cooling channel can be achieved. The busbar 10 can thus be cooled effectively. This makes it possible to either conduct a higher current than without such cooling or, alternatively, to design the busbar 10 with a smaller cross section. The housing recess 13 makes it possible to simply and inexpensively install the busbar 10.

[0036] In order to improve the heat transfer, it is advantageously provided that a heat-conducting material is installed in the housing recess 13 between the cooling shoulder 12 and the bearing cover 7. This can be a heat-conducting adhesive in particular. As a result, heat can be optimally conducted from the busbar 10, in particular from the cooling shoulder 12 of the busbar 10, through the bearing cover 7 to the coolant in the second cooling channel 9.

[0037] Figure 4 A cross section through at least a portion of the electrical machine 1 is schematically shown. Figure 4 , in particular, the coupling of one of the first cooling channels 6 to one of the second cooling channels 9 is shown. It is also shown that the cooling jacket 5 extends around the stator 3. The stator 3 in turn has a stator winding 14, which is electrically contacted via busbars 10. In particular, this is a three-phase stator winding, so that each busbar of the busbars 10 is provided for energizing one phase of the stator winding 14.

[0038] The cooling medium flowing through the first cooling channel 6 and the second cooling channel 9 also automatically reaches the area of ​​the second cooling channel 9 framed by the cooling shoulder 12. As an alternative, when there is only one cooling shoulder 12, the cooling medium can also be introduced into the corresponding second cooling channel 9 beside the remaining cooling shoulder 12. In any case, heat transfer between the cooling shoulder 12 and the cooling medium can be carried out, so that the busbar 10 is cooled.

[0039] The cooling jacket 5 and the bearing cover 7 can be made of a metallic material and / or of a plastic. The metallic material can achieve in particular a better conductivity, wherein due to the arrangement of the busbar 10 along one of the second cooling channels 9 an optimal heat dissipation can be achieved with the aid of the coolant. If the bearing cover is made of a metallic material, it is provided that an electrically insulating material is present between the bearing cover 7 and the busbar 10. This can be in particular an electrically insulating adhesive and / or a protective lacquer and / or an insert.

[0040] Figure 5 A schematic partial view of a busbar 10 is shown. The busbar 10 has a main section 11 and two cooling ridges 12 connected thereto. The cooling ridges 12 and the main section 11 can be formed in one piece, wherein in this case the busbar 10 is preferably a stamped and bent part, such as in particular in Figure 3 As an alternative, the cooling shoulder 12 can be a separate element, which is connected to the main region 11 by means of a joining method. Such a method can be in particular a mechanical method, such as riveting and / or crimping, alternatively the connection between the main section 11 and the cooling shoulder 12 can be formed by a thermal method, such as soldering and / or welding.

[0041] As a result, the busbar 10 can be manufactured and assembled simply and cost-effectively. At the same time, the busbar 10 can achieve stable and reliable heat dissipation through the coolant flowing through the first cooling channel 6 and the second cooling channel 9 .

Claims

1. A motor (1) having a rotor (2) and a stator (3), said rotor (2) and stator (3) being at least partially arranged in a machine housing (4), and A cooling jacket (5) for cooling the stator (3), a plurality of mutually parallel first cooling channels (6) extending through the cooling jacket (5) for guiding a cooling medium, The machine housing (4) has at least one bearing cover (7) connected to the cooling jacket (5) for supporting a rotor shaft (8) of the rotor (2). A plurality of second cooling channels (9) are formed on the bearing cover (7), wherein the plurality of second cooling channels (9) respectively connect two first cooling channels (6) to each other in terms of flow. wherein the second cooling channel (9) and the first cooling channel (6) form a coolant path passing through the motor (1), and At least one busbar (10) extends at the bearing cover (7), and the busbar (10) is electrically connected to the stator winding (14) of the stator (3). It is characterized in that The busbar (10) comprises a main section (11) and at least one cooling shoulder (12) extending from the main section (11), wherein the cooling shoulder (12) engages in a housing recess (13) of the bearing cover (7), the housing recess (13) being designed to be directly adjacent to one of the second cooling channels (9); the cooling shoulder (12) of the busbar (10) is directly adjacent to one of the second cooling channels (9), wherein the second cooling channel (9) is arranged between a radially outer channel wall of the bearing cover (7) and a radially inner channel wall of the bearing cover (7), wherein the housing recess (13) of the bearing cover (7) is directly adjacent to the radially outer channel wall or the radially inner channel wall; and the cooling shoulder (12) of the busbar (10) projects into the housing recess (13) of the bearing cover (7) in the axial direction.

2. The electric machine (1) according to claim 1, characterized in that The cooling jacket (5) is a partial region of the stator (3) or a part of a machine housing (4) which surrounds the stator (3) at least partially.

3. The electric machine (1) according to claim 1 or 2, characterized in that The busbar (10) has two cooling shoulders (12), which are each arranged in a separate housing recess (13), wherein the two housing recesses (13) are formed on both sides of one of the second cooling channels (9).

4. The electric machine (1) according to claim 1 or 2, characterized in that A heat conducting material is inserted between the cooling shoulder (12) and the bearing cover (7).

5. The electric machine (1) according to claim 1 or 2, characterized in that: An electrically insulating material is inserted between the cooling shoulder (12) and the bearing cover (7).

6. The electric machine (1) according to claim 1 or 2, characterized in that A main region (11) of the busbar (10) is formed integrally with a cooling shoulder (12) of the busbar (10).

7. The electric machine (1) according to claim 1 or 2, characterized in that The main region (11) of the busbar (10) and the cooling shoulder (12) of the busbar (10) are separate elements which are connected to one another by a joining method.

8. The electric machine (1) according to claim 7, characterized in that The main region (11) and the cooling shoulder (12) are connected in a materially locking manner and / or in a force-locking manner and / or in a form-locking manner.

9. The electric machine (1) according to claim 1 or 2, characterized in that The stator winding (14) is a three-phase winding, wherein three busbars (10) are provided, and each of the three busbars (10) is electrically connected to a phase of the stator winding (14).

10. The electric machine (1) according to claim 1 or 2, characterized in that The cooling jacket (5) and / or the bearing cover (7) are made of metal material and / or plastic.

11. The electric machine (1) according to claim 1 or 2, characterized in that The cooling jacket (5) is hollow-cylindrical in design, wherein the first cooling channel (6) is arranged along a central axis of the hollow cylinder, and wherein the bearing cover (7) closes the cooling jacket (5) at the end face.

12. The electric machine (1) according to claim 1 or 2, characterized in that The busbar (10) with the cooling shoulder (12) is injected into the bearing cover (7).

13. The electric machine (1) according to claim 1, characterized in that A plurality of mutually parallel first cooling channels (6) extending in the axial direction with respect to the stator axis extend through the cooling jacket (5) for guiding a cooling medium.

14. The electric machine (1) according to claim 1, characterized in that The plurality of second cooling channels (9) respectively connect two adjacent first cooling channels (6) to each other in terms of flow.

15. The electric machine (1) according to claim 1, characterized in that The coolant path is designed in a meandering or serpentine manner.

16. The electric machine (1) according to claim 1, characterized in that The cooling jacket (5) is a partial region of the stator laminated core.

17. The electric machine (1) according to claim 1 or 2, characterized in that A heat-conducting adhesive is inserted between the cooling shoulder (12) and the bearing cover (7).

18. The electric machine (1) according to claim 1 or 2, characterized in that An electrically insulating adhesive and / or protective lacquer and / or insert is inserted between the cooling shoulder (12) and the bearing cover (7).

19. The electric machine (1) according to claim 6, characterized in that The busbar (10) is manufactured as a stamped and bent part.

20. The electric machine (1) according to claim 7, characterized in that The main region (11) and the cooling shoulder (12) are soldered and / or welded and / or connected in a non-positive manner by a press connection and / or connected in a positive manner by a riveted connection.

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