Electric machine having a cooling system

Abstract

The invention relates to an electric machine (1) comprising a stator (3) arranged in a machine housing (2) and a rotor which is mounted so as to be rotatable about an axis of rotation (4) relative to the stator (3), wherein at least one coolant inlet (5) for supplying pressurised coolant and at least one coolant outlet (6) for discharging coolant are installed in the machine housing and / or directly or indirectly on the machine housing (2), wherein the coolant inlet (5) and the coolant outlet (6) are formed in the region of a first axial end (7) of the stator (3).

Description

[0001] Electric machine with a cooling

[0002] Field of the invention

[0003] The present invention relates to an electrical machine having a stator arranged in a machine housing and a rotor mounted rotatably about a rotational axis with respect to the stator, wherein at least one coolant inlet for supplying pressurized coolant and at least one coolant outlet for discharging coolant are formed in the machine housing and / or directly or indirectly applied to the machine housing.

[0004] State of the art

[0005] Electrical machines are used to convert electrical energy into mechanical energy and vice versa and are often used as motors and / or generators in the field of automotive engineering.

[0006] Electrical machines generally comprise a stationary stator and a movable rotor, with the rotor in the most common design of an electrical machine being rotatably mounted within a ring-shaped stator.

[0007] Stators for electrical machines have a winding system in stator slots which, when energized, generates a magnetic field and, due to electromagnetic interaction with a rotor, causes a rotary movement of a rotor shaft that is non-rotatably connected to the rotor. During operation of the electrical machine, heat is generated which must be dissipated to prevent overheating and the associated damage or even destruction of the stator. For this purpose, stators are usually equipped with a cooling system to cool the stator, in particular the winding system. Such a cooling system comprises one or more cooling channels through which a coolant flows and which are ideally located in the stator close to the winding system. Heat can be dissipated from the stator by heat transfer from the winding system to the coolant.In this way, overheating of the stator windings and, associated with this, damage or even destruction of the stator can be avoided.

[0008] Summary of the invention

[0009] It is an object of the invention to provide an electrical machine which is characterized by optimized cooling of the stator and at least one phase connection of the stator.

[0010] This need can be met by the subject matter of the present invention according to independent claim 1. Advantageous embodiments of the present invention are described in the dependent claims.

[0011] The electrical machine according to the invention comprises a stator arranged in a machine housing and a rotor mounted so as to be rotatable about an axis of rotation with respect to the stator.

[0012] According to the invention, at least one coolant inlet for supplying pressurized coolant and at least one coolant outlet for discharging coolant are formed in the machine housing and / or directly or indirectly on the machine housing, wherein the coolant inlet and the coolant outlet are formed in the region of a first axial end of the stator of the electrical machine.

[0013] In this context, the term “attached to the machine housing” means that the coolant inlet and / or the coolant outlet is formed on a further component of the electrical machine, wherein the term “direct” describes a, preferably fixed, connection of the further component of the electrical machine to the machine housing and the term “indirect” describes a, preferably fixed, connection of the further component via at least one further component of the electrical machine to the machine housing.

[0014] According to the invention, the coolant inlet opens into an annular first coolant distribution chamber in the region of the first axial end of the stator, wherein the first coolant distribution chamber is fluidly connected to at least one first coolant channel of the stator.

[0015] Furthermore, according to the invention, the first coolant channel extends axially through a stator laminated core of the stator and opens in the region of a second axial end of the stator into a second coolant distribution chamber, which is further fluidly connected to at least one second coolant channel and at least one third coolant channel of the stator.

[0016] The first coolant channel can extend axially straight, meandering or stepped through the stator laminated core of the stator.

[0017] According to the invention, the second coolant channel and the third coolant channel extend axially through the stator core of the stator and open into a third coolant distribution chamber in the region of the first axial end of the stator, which is fluidly connected to the coolant outlet. According to the present invention, a first winding head of the stator is arranged in the second coolant distribution chamber, and a second winding head of the stator and at least one phase connection of the stator are arranged in the third coolant distribution chamber.

[0018] The first coolant channel is preferably formed in the region of an outer circumference of the stator laminated core in the stator laminated core.

[0019] The second coolant channel is preferably formed at least partially in a region between two grooves in the stator laminated core.

[0020] The third coolant channel is preferably formed in a groove of the stator laminated core.

[0021] The first coolant distribution chamber can be formed in a housing wall of the machine housing or can be partially delimited by the housing wall.

[0022] The flow direction of the coolant through the first coolant channel is preferably opposite to the flow direction of the coolant in the second coolant channel and the third coolant channel. However, a parallel flow direction is also conceivable.

[0023] In a particularly preferred embodiment, an annular coolant guide device is arranged in the region of the first axial end and in the region of the second axial end of the stator, namely a first coolant guide device at the first axial end and a second coolant guide device at the second axial end, the shape of which at least partially follows the outer contour of the respective winding overhang. The first coolant guide device (21) and the second coolant guide device (22) are preferably each designed as one or more parts, at least two parts.

[0024] The first coolant guide device in the region of the first axial end and thus in the region of the second winding head of the stator preferably at least partially delimits the first coolant distribution space.

[0025] The inventive design of the electrical machine makes it possible to generate optimized cooling of the stator of the electrical machine and its phase connections in a simple manner.

[0026] Brief description of the drawings

[0027] The invention is described below by way of example with reference to the drawings.

[0028] Fig. 1 shows a partial longitudinal section of an electrical machine.

[0029] Fig. 2 essentially shows a perspective view of a

[0030] Stator of an electrical machine according to Fig. 1 .

[0031] Fig. 3 shows an exploded view of a stator according to Fig. 2.

[0032] Fig. 4 shows a cross-sectional view of a stator according to Fig.

[0033] 2.

[0034] Fig. 5 shows a detail C from Fig. 4. Fig. 6 shows a longitudinal sectional view of the detail from Fig. 5 along the section plane AA from Fig. 4.

[0035] Fig. 7 shows a partial cross-sectional view through a stator laminated core of a stator according to Fig. 2.

[0036] Detailed description of the invention

[0037] Fig. 1 shows a partial longitudinal section through an electrical machine 1. The electrical machine 1 has a machine housing 2, a stator 3 fixedly arranged in the machine housing 2, and a rotor mounted for rotation about an axis of rotation 4 relative to the stator 3. The rotor is shown in Fig.

[0038] 1 not shown. The rotor is separated from the stator 3 by a separator sleeve 27 (Fig. 3).

[0039] In Fig. 2 to Fig. 7, the stator 3 from Fig. 1 is shown in different representations and levels of detail. The stator 3 comprises a stator laminated core 11, also called a stator core, at whose two axial ends 7, 12 a winding head 17, 18 is formed - at a first axial end 7, a second winding head 18 is formed, and at a second axial end 12, a first winding head 17. Furthermore, three phase connections 19 are formed in the region of the first axial end 7 of the stator 3.

[0040] At each of the two axial ends 7, 12 of the stator 3, a substantially annular coolant guide plate 21, 22 is arranged, namely a first coolant guide device 21 at the first axial end 7 and a second coolant guide device 22 at the second axial end 12. The shape of the first coolant guide device 21 and the second coolant guide device 22 essentially follows an outer contour of the respective winding head 17, 18 and is arranged coaxially to the stator and rotor, respectively (Fig. 2, Fig. 3). In the present exemplary embodiment, the first coolant guide device 21 is designed in three parts, with one of the parts of the first coolant guide device 21 having a formation 23 for receiving the phase connections 19 (Fig. 2 - Fig. 6). However, this coolant guide device can also be designed in different parts, for example in one part, two parts, or multiple parts.

[0041] The direction "axial" essentially corresponds to a direction along or parallel to the rotational axis 4 of the electrical machine 1. The direction "radial" essentially corresponds to a direction normal to the rotational axis 4 of the electrical machine 1.

[0042] To cool the electric machine 1, a coolant inlet 5 and a coolant outlet 6 are formed on or in the machine housing 2, on a circumference 24 of the machine housing 2, in the region of the first axial end 7 of the stator 3. The coolant inlet 5 serves to supply a pressurized coolant into an annular first coolant distribution chamber 9. The first coolant distribution chamber 9 is fluidly connected to a plurality of first coolant channels 10. The first coolant channels 10 each extend axially, namely from one axial end 7, 12 of the stator 3 to the other axial end 7, 12 of the stator 3, through the stator laminated core 11 of the stator 3 and are formed at the edge, i.e. in the region of an outer circumference 8 of the stator laminated core 11, evenly distributed with respect to the outer circumference 8 of the stator laminated core 11.The first cooling channels 10 all open into a second coolant distribution chamber 13 in the region of the second axial end 12 of the stator 3. The second coolant distribution chamber 13 is in turn fluidly connected to a plurality of second coolant channels 14 and a plurality of third coolant channels 15. The second coolant channels 14 and the third coolant channels 15 also extend axially through the stator core 11. In the present exemplary embodiment, a second coolant channel 14 is always formed essentially in the region between two adjacent grooves 20 of the stator core 11. The third coolant channels 15 are each arranged in a groove 20 of the stator core 11. All second cooling channels 14 and third cooling channels 15 open, starting from the second coolant distribution chamber 13, into a third coolant distribution chamber 16.The third coolant distribution chamber 16 is formed in the region of the first axial end 7 of the stator 3 and is fluidly connected to the coolant outlet 6. The coolant outlet 56 serves to discharge the coolant from the third coolant distribution chamber 16. The individual coolant channels 10, 14, 15 and their positioning are shown as examples in Fig. 1 and Fig. 7.

[0043] To cool the electrical machine, coolant is pumped under pressure via the coolant inlet 5 on the circumference 24 of the machine housing 2 into the first coolant distribution chamber 9. Starting from the first coolant distribution chamber 9, the coolant flows via the first coolant channels 10 to the second coolant distribution chamber 13. From there, the coolant flows via the second coolant channels 14 and the third coolant channels 15 to the third coolant distribution chamber 16 in the region of the first axial end 7 of the stator 3. From there, the coolant flows out via the coolant outlet 6. In the present exemplary embodiment, the coolant outlet 6 is designed to be attached to the machine housing 2 in that it is formed by the formation 23 for guiding the phase connections 19. The connection between the machine housing 2 and the first coolant baffle 21 can be seen in Fig. 1 and Fig. 6.

[0044] The flow direction of the coolant through the first coolant channel 10 is opposite to the flow direction of the coolant through the second coolant channel 14 and the third coolant channel 15. The flow direction of the coolant through the first coolant channel 10 is schematically illustrated in Fig. 1 by a first arrow 25. The flow direction of the coolant through the second coolant channel 14 and the third coolant channel 15 is schematically illustrated in Fig. 1 by a second arrow 26. List of reference symbols

[0045] Electric machine

[0046] Machine housing

[0047] stator

[0048] axis of rotation

[0049] Coolant inlet

[0050] Coolant outlet

[0051] First axial end

[0052] Outer circumference (of the stator core)

[0053] First coolant distribution chamber

[0054] First coolant channel

[0055] Stator laminated core

[0056] Second axial end

[0057] Second coolant distribution chamber

[0058] Second coolant channel

[0059] Third coolant channel

[0060] Third coolant distribution chamber

[0061] First winding head

[0062] Second winding head

[0063] Phase connection

[0064] Nut

[0065] First coolant guide device

[0066] Second coolant guide device

[0067] Formation (to accommodate the phase connections)

[0068] Scope (of the machine housing)

[0069] First arrow

[0070] Second arrow

[0071] Separator sleeve

Claims

Patent claims 1. An electrical machine (1) comprising a stator (3) arranged in a machine housing (2) and a rotor mounted so as to be rotatable about a rotational axis (4) relative to the stator (3), wherein at least one coolant inlet (5) for supplying pressurized coolant and at least one coolant outlet (6) for discharging coolant are formed in the machine housing and / or directly or indirectly on the machine housing (2), wherein the coolant inlet (5) and the coolant outlet (6) are formed in the region of a first axial end (7) of the stator (3), and wherein the coolant inlet (5) opens into an annular first coolant distribution chamber (9) in the region of the first axial end (7) of the stator (3), which is fluidically connected to at least one first coolant channel (10) of the stator (3),wherein the first coolant channel (10) extends axially through a stator laminated core (11) of the stator (3) and opens in the region of a second axial end (12) of the stator (3) into a second coolant distribution chamber (13), which is further fluidically connected to at least one second coolant channel (14) and at least one third coolant channel (15) of the stator (3), wherein the second coolant channel (14) and the third coolant channel (15) extend axially through the stator laminated core (11) of the stator (3) and open in the region of the first axial end (7) of the stator (3) into a third coolant distribution chamber (16), which is fluidically connected to the coolant outlet (6), wherein a first winding head (17) of the stator (3) is arranged in the second coolant distribution chamber (13), and a second winding head (18) of the stator (3) and at least one phase connection are arranged in the third coolant distribution chamber (16). (19) of the stator (3)., 2. Electrical machine (1) according to claim 1, characterized in that the first coolant channel (10) is formed in the region of an outer circumference (8) of the stator laminated core (11).

3. Electrical machine (1) according to claim 1 or 2, characterized in that the second coolant channel (14) is formed at least partially in a region between two grooves (20) in the stator laminated core (11).

4. Electrical machine (1) according to claim 1, 2 or 3, characterized in that the third coolant channel (15) is formed in a groove (20) of the stator laminated core (11).

5. Electrical machine (1) according to one of claims 1 to 4, characterized in that the first coolant distribution chamber (9) is formed in a housing wall of the machine housing (2) or is partially delimited by the housing wall.

6. Electrical machine (1) according to one of the preceding claims, characterized in that the flow direction (25) of the coolant through the first coolant channel (10) is opposite to the flow direction (26) of the coolant in the second coolant channel (14) and the third coolant channel (15).

7. Electrical machine (1) according to one of the preceding claims, characterized in that in the region of the first axial end (7) and in the region of the second axial end (12) of the stator (3) there is arranged in each case an annular coolant guide device (21, 22), which in its respective shape at least partially follows the outer contour of the respective winding head (17, 18).

8. Electrical machine (1) according to claim 7, characterized in that the first coolant guide device (21) and the second coolant guide device (22) are each designed in one part or in several parts, at least in two parts.

9. Electrical machine (1) according to claim 7 or 8, characterized in that the first coolant guide plate (21) at least partially delimits the first coolant distribution space (9) in the region of the first axial end (7) and thus in the region of the second winding head (18) of the stator (3).

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