Stator of an electric machine

Abstract

To reduce the requirement of installation space of a stator for an electric machine, and to improve efficiency.SOLUTION: The present invention relates to a stator (5) for an electric machine (2), the stator being provided with a carrier body (11) having a slot structure (9), and electric conductors (1) arranged in the slot structure (9). At the same time, due to the increase of efficiency having a compact structure, the slot structure (9) has a total of 48 slots (S) and eight layers (L). Each of the layers (L) is occupied at least once by at least one of branches (a to l) of a total of three phases (U, V, W). The invention further relates to the electric machine (2) provided with such the stator (5).SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a stator for an electric machine, which has a carrier body with a groove structure for receiving an electric conductor (wire) and is capable of generating at least one magnetic field during operation. The present invention also relates to an electric machine comprising such a stator.

[0002] Electric machines are being used in an increasing number of applications. In particular, the power supply of automobiles requires electric machines with increased efficiency and / or reduced installation space. In automobiles, for example, electric machines are used to drive the automobile.

[0003] This type of electric machine has a stator by which, during operation, at least one magnetic field is generated, which cooperates with a corresponding rotor of the electric machine to set the rotor in rotation. Alternatively, the rotation of the rotor can induce a field in the stator that can be coupled, for example, in the form of an electric voltage.

[0004] A typical stator has a carrier body with a groove structure, which includes several grooves arranged in a circumferentially alternating sequence, typically symmetrically or evenly distributed in the circumferential direction. Several electrical conductors of the stator, arranged in a circumferentially alternating sequence within the grooves, are typically received within each groove. The successive electrical conductors form multiple layers within each groove, so that the overall groove structure has a specified number of grooves as well as multiple layers. To increase the efficiency of the stator, it is particularly important how the electrical conductors are arranged in the groove structure.

[0005] For example, a stator having a groove structure with a total of 108 grooves arranged successively in an alternating manner in the circumferential direction is known from US Pat. No. 5,649,999, in which four layers of electrical conductors are received in each groove, so that the groove structure has a total of 108 grooves and four layers.

[0006] A stator with a groove structure having a total of 72 grooves and four layers is known from US Pat. No. 5,649,999.

[0007] Patent Document 3 shows a stator for an electric machine having a carrier body extending in both the axial and circumferential directions. The carrier body has a groove structure with a total of 90 grooves. The stator further has electrical conductors arranged in eight layers within each groove, resulting in a total of 90 grooves and eight layers. The electrical conductors are electrically interconnected into a total of three phases, each phase having a total of six branches connected in parallel. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] US Patent Application Publication No. 2005 / 0258703 [Patent Document 2] US Patent Application Publication No. 2015 / 0028713 [Patent Document 3] US Patent Application Publication No. 2018 / 0097431 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention aims to improve upon the above and other embodiments of the electric machine stator to reduce installation space requirements and improve efficiency. [Means for solving the problem]

[0010] This object is solved according to the invention by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0011] The present invention is based on the general concept of providing a groove structure for a stator for an electric machine having a total of 48 grooves, with eight layers of electrical conductors arranged in each case, the electrical conductors interconnected into a total of three electrical phases, each phase having a total of three branches connected in parallel, and each branch arranged in at least one of the total eight layers in the groove structure. In addition to a compact construction of the stator and thus the corresponding electric machine, the generation of circulating currents by the electrical conductors during operation of the corresponding electric machine is thus prevented or at least reduced, resulting in an increased efficiency of the stator and therefore the corresponding electric machine.

[0012] According to the concept of the present invention, a rotor includes a carrier body. The carrier body preferably extends axially and circumferentially and is formed as a hollow cylinder. The carrier body has a groove structure. The groove structure has a total of 48 grooves radially opening on one side, with a total of eight layers of electrical conductors disposed within the grooves. Thus, the groove structure has a total of 48 grooves and eight layers. A corresponding electrical conductor is disposed in each layer of each groove. Thus, each layer of each groove is occupied by a corresponding electrical conductor. When current is supplied, the electrical conductors operate to generate at least one magnetic field, electrically interconnecting a total of three phases. Thus, the stator is particularly suitable for a three-phase machine. Each phase thus has a total of four branches, also called "branches" or windings, connected in parallel. According to the present invention, each branch is disposed in at least two grooves, and each branch is disposed at least once in each layer of the groove structure. This means that all branches of each phase are disposed at least once in each of the eight layers of the groove structure and in at least two different grooves.

[0013] Each branch has at least one electrical conductor or is composed of at least one electrical conductor. The at least one electrical conductor of each branch is electrically connected in series, i.e., flows electrically in series during operation. This can be achieved, for example, by one or more connected electrical conductors arranged one behind the other and electrically connected in series. Thus, each branch has at least one electrical conductor, and the electrical conductors are electrically connected in series. Therefore, in principle, each branch can have a single electrical conductor. However, embodiments are also conceivable in which at least one of the at least one branches, and advantageously, each branch, has at least two electrical conductors electrically connected in series with each other.

[0014] Advantageously, the grooves of the groove structure are radially open on the inside. Advantageously, the grooves of the groove structure are further arranged so as to be uniformly distributed. Advantageously, the grooves arranged successively in alternating circumferential directions are separated from one another by teeth of the carrier body. On the side facing away from the open side of the grooves, i.e., on the side facing radially, in particular on the outer side, the carrier body can have an electrically conductive and / or ferritic jacket surface, in particular an outer jacket surface. Alternatively or additionally, the carrier body can be a mover or part of a mover of a corresponding electric machine.

[0015] The arrangement of the branches within the channel structure, i.e. within each corresponding channel and layer, includes the path of the branches in both axial directions, i.e. in particular the electrical flow-through of the branches in both axial directions.

[0016] In a corresponding electric machine, the stator cooperates in a known manner with a corresponding rotor, which for this purpose can be magnetic or can have magnetic parts.

[0017] An embodiment in which the stator has a total of eight poles may be advantageous, as this leads to an increased efficiency of the stator and therefore of the corresponding electric machine, which at the same time has a compact structure.

[0018] In a preferred embodiment, the branches are arranged circumferentially symmetrically in the groove structure, which in particular means that the arrangement of the branches in the groove structure repeats itself in the circumferential direction, in other words, the arrangement of the branches in the groove structure is at least doubly symmetric with respect to rotation around the axially longitudinal central axis of the stator.

[0019] Thus, an embodiment in which each branch is located in four grooves of each layer, and the eleventh groove is located between the grooves, and this layer does not contain this branch, is considered preferable. In other words, every twelfth groove is occupied by the same branch on each layer. This, in particular, leads to a four-fold symmetrical arrangement of the branches around the longitudinal central axis of the stator. For example, a branch can be located in the first layer of the first groove and in the first layer of the thirteenth groove, while the first layers of the second to twelfth grooves are free from this branch. This, in particular, leads to a reduction in circulating currents in the electrical conductors and branches, which leads to an increase in the efficiency of the stator and, therefore, the corresponding electric machine. Therefore, the above-mentioned arrangement of branch portions electrically flowing in the same axial direction is advantageous.

[0020] In an advantageous embodiment, branches of the same phase are arranged in each of four consecutive layers of each groove. This means that different branches of the same phase are arranged alternately in the four layers of the same groove. Two branches of the same phase are particularly arranged alternately in the four layers. This also leads to a reduction in circulating currents in the electrical conductors and thus an increase in efficiency. Furthermore, it is preferable that branches flowing axially in the same direction are arranged alternately in this arrangement.

[0021] An embodiment is preferred in which two different branches of the same phase are arranged in two consecutive grooves in each layer. This means that two consecutive grooves of the same phase branch are each occupied in each layer of the groove structure. In particular, a phase change occurs in each layer downstream from the two grooves, so that two branches of two different phases are arranged in four consecutive grooves in the same layer. This leads to a further reduction in the electrical circulating currents in the electrical conductors and therefore to an increase in the efficiency of the stator.

[0022] In principle, the electrical conductors of the stator can have any cross section, where the cross section is given in particular by a plane normal to the axial direction.

[0023] In a preferred embodiment, the electrical conductors each have a rectangular cross section. Therefore, the electrical conductors can be more compactly and / or more densely arranged within the grooves. This increases the efficiency of the stator and, correspondingly, the efficiency of the electric machine. Therefore, it is preferred that all branches or electrical conductors each have the same cross section.

[0024] The electrical conductors and branches can in principle be arranged in any way within the channel structure.

[0025] It is particularly conceivable that the electrical conductors are arranged in the groove structure as at least one wave winding, in which case the electrical conductors or windings, respectively, are prepared and then introduced radially into the groove structure.

[0026] Similarly, it is conceivable that the electrical conductors are arranged in the groove structure as hairpins arranged successively in alternating circumferential directions, whereby the hairpins are introduced axially into the groove structure.

[0027] It is also conceivable that the electrical conductor, and therefore the branch, exists partly as a wave winding and partly as a hairpin.

[0028] The stator according to the invention can be used in any kind of electric machine, which of course also falls within the scope of the invention.

[0029] The electric machine is in particular an electric motor. The electric machine is preferably used in a motor vehicle and serves, for example, to drive the motor vehicle. The electric machine can therefore be the drive motor of the motor vehicle.

[0030] Further important features and advantages of the invention emerge from the dependent claims, from the drawings and from the corresponding figure descriptions based on the drawings.

[0031] It goes without saying that the above features and characteristics described below can be used not only in specific combinations but also in other combinations or alone without departing from the scope of the present invention.

[0032] Preferred exemplary embodiments of the present invention are illustrated in the drawings and will be explained in more detail in the following description, where like reference numbers indicate identical, similar or functionally identical elements. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a simplified diagram showing a vehicle equipped with a highly simplified electric machine; [Figure 2] 1 is a cross-sectional view of an electric machine comprising a stator and a rotor; [Figure 3] 1 is a schematic cross-sectional view of a stator including a groove structure and electrical conductors housed in the groove structure; [Figure 4] FIG. 1 is a circuit diagram of the electrical connections of electrical conductors. [Figure 5] 4 of another exemplary embodiment. FIG. [Figure 6] FIG. 1 shows a stator consisting of a groove structure and electrical conductors. [Figure 7] FIG. 1 shows a stator consisting of a groove structure and electrical conductors. [Figure 8]FIG. 8 is a view equivalent to FIG. 7 for another exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0034] An electric machine 2 having a conductor 1 is used in particular in a motor vehicle 3 (see FIG. 1), as shown in FIGS. 1 to 8. In the motor vehicle 3, the electric machine 2 can serve to drive the motor vehicle 3 and can therefore be designed as an electric motor 4, in particular a drive motor 17.

[0035] According to FIG. 2, the electric machine 2 has a stator 5 formed in the shape of a hollow cylinder and extending in an axial direction 6, which in FIG. 2 also extends perpendicularly to the plane of the drawing and in a circumferential direction 7. The electric machine 2 further has a rotor 8 arranged coaxially with the stator 5. The rotor 8 is arranged, in particular, within the stator 5. The conductors 1 are also part of the stator 5 and are arranged in a groove structure 9 of the stator 5. The rotor 8 cooperates with the stator 5 to drive, for example, a vehicle 3. For this purpose, the rotor 8 can be at least partially magnetic. To drive the motor vehicle 3, the stator 5, which is made up of the conductors 1, generates at least one magnetic field, which rotates the rotor 8. As shown in FIG. 1, the rotation of the rotor 8 is transmitted to wheels 10 and / or corresponding wheel axles (not shown) of the vehicle 3 to drive the vehicle 3.

[0036] As can be seen in particular from FIGS. 3 and 7 and 8, the stator 5 has a carrier body 11, which extends in the axial direction 6 and the circumferential direction 7 like a hollow cylinder and has a groove structure 9. The corresponding views of the stator 5 are shown in FIGS. 3 and 6 to 8, where the axial direction 6 runs perpendicular to the plane of the paper, but for better understanding, the circumferential direction 7 is assumed to be straight and to be within the plane of the paper. The groove structure 9 has a total of 48 grooves S, of which a section with a total of seven grooves S is seen, as shown in FIG. 3. These grooves S are distributed in the circumferential direction 7 and are arranged so as to be spaced apart from one another and evenly, i.e., in particular equidistantly in the circumferential direction 7. The grooves S open radially inward and on the side facing the rotor 8. In each case, the teeth 12 of the carrier body 11 are arranged between successive grooves S, so that the grooves S are separated from one another in the circumferential direction 7 by the teeth 12. The grooves S are numbered consecutively starting with S1 in the corresponding drawings. Thus, the groove structure 9 includes a first groove S1, a second groove S2 following the first groove S1 in the circumferential direction 7, a third groove S3 following the second groove S2 in the circumferential direction 7, and so on. Thus, the groove structure includes a total of 48 grooves S along the circumferential direction 7 from the first groove S1 to the 48th groove S48. Eight layers of conductors 1 are housed or arranged in succession, radially alternating, in each groove S, for a total of eight layers of conductors 1 in each groove S. The layers L are also numbered consecutively starting with L1 in the drawings. This means that the first layer L1, the second layer L following the first layer L1 in the radial direction, the third layer L3 following the second layer L2 in the radial direction, and so on are arranged in each groove S. The first layer L1 is thus the outer layer L located radially outward, and the eighth layer L8 is the layer L adjacent to the first layer L1 in the radial direction and closest to the rotor 8. In this way, the groove structure 9 has a total of 48 grooves S, similar to the eighth layer L8.

[0037] 4 and 5, the conductors are electrically interconnected into a total of three phases U, V, and W. Thus, the phases U, V, and W have a total of four electrically parallel branches a, b, c, d, e, f, g, h, i, j, k, and l (a to l). The branches a to l are also referred to as "branches" or windings 13. This means that the first phase U has a first branch a, a second branch b, a third branch g, and a fourth branch h, and the branches a, b, g, and h of the first phase U are electrically connected in parallel. The second phase V has a first branch c, a second branch d, a third branch i, and a fourth branch j, and the total four branches c, d, i, and j of the second phase V are electrically connected in parallel. Similarly, the third phase W includes a first branch e, a second branch f, a third branch k, and a fourth branch l, and all four branches e, f, k, and l of the third phase W are electrically connected in parallel. Each of the branches a to l includes at least one conductor wire 1.

[0038] FIG. 6 shows the occupation of each layer L of each groove S and each conductor 1 electrically connected in series for each branch a-l. For ease of understanding, the numbering of the grooves S in FIG. 6 only specifies the respective numbers, and a corresponding conductor of one of the branches a-l is arranged in each groove S and in each layer L, so that each layer L of each groove S is occupied by the conductor 1 of the corresponding branch a-l. For this reason, in FIG. 6, each conductor 1 is followed by the branch a-l to which the conductor 1 belongs, but for ease of understanding, it is assumed that each branch a-l includes only one conductor 1. Needless to say, each branch a-l can also include multiple conductors 1 electrically connected to each other in series or in series. As can be seen from FIG. 6, the first branch a of the first phase U is arranged, for example, in the first layer L1 of the first groove S1. Thus, the first layer L1 of the first groove S1 is occupied by the first branch a of the first phase U, the first layer L1 of the second groove S2 is occupied by the second branch b of the first phase U, the first layer L1 of the third groove S3 is occupied by the second branch d of the second phase V, the first layer L1 of the fifth groove S5 is occupied by the first branch e of the third phase W, the first layer L1 of the seventh groove S7 is occupied by the third branch g of the first phase U, and the first layer L1 of the eighth groove S8 is occupied by the fourth branch h of the first phase U. The first layer L1 of the ninth groove S9 is occupied by the third branch i of the second phase V. The first layer L1 of the tenth groove S10 is occupied by the fourth branch j of the second phase V, the first layer L1 of the eleventh groove S11 is occupied by the third branch k of the third phase W, and the first layer L1 of the twelfth groove S12 is occupied by the fourth branch l of the third phase W. As can be further seen from Figure 6, in the diagram of Figure 6, each branch a-l below the branches a-l is additionally assigned a direction in which this branch a-l flows along the axial direction 6. Thus, an "x" means that the corresponding branch a-l flows into the plane of the page in the axial direction 6, and a "·" means that the corresponding branch a-l flows out of the plane of the page in the axial direction 6. In this way, the first branch a of the first phase U in the first layer L1 of the first groove S1 flows into the plane of the page in the axial direction 6, while the first branch a in the second layer L2 of the eighth groove S8 flows out of the plane of the page in the axial direction 6.

[0039] 7 shows the stator 5 in the representation of FIG. 3 in the case of the occupancy of the groove structure 9 according to FIG. 6, where the branches a, b, g, h of the first phase U are shown in a hatched or filled manner, respectively. The filled-in fields in FIG. 7 thus correspond to the occupancy or arrangement of the first branch a of the first phase U, respectively, and as can be seen in particular from FIGS. 6 and 7, each branch a-l is arranged in at least two grooves S of the groove structure 9, and each branch a-l is arranged at least once in each of the layers L of the groove structure 9. This means that each phase U, V, W of branches a-l is arranged in at least two grooves S of the groove structure 9, occupying each of the total eight layers L of the groove structure 9 at least once. In the exemplary embodiment shown in FIGS. 6 and 7, each branch a-l thereby occupies each of the layers L four times. The first branch a of the first phase U occupies the first layer L1 in, for example, the first groove S1, the thirteenth groove S13, the twenty-fifth groove S25, and the thirty-seventh groove S37. The third branch i of the second phase V occupies the first layer L1 in the ninth groove S9, the twenty-first groove S21, the thirty-third groove S33, and the forty-fifth groove S45. The fourth branch l of the third phase W occupies the first layer L1 in the twelfth groove S12, the twenty-fourth groove S24, the thirty-sixth groove S36, and the forty-eighth groove S48. In the exemplary embodiment of FIGS. 6 and 7 , the same branches a-l are arranged four times in each layer L in four grooves S, with eleven grooves S without branches a-l in the same layer L being arranged between grooves S occupied by the same branches a-l in the same layer L. In other words, each of the twelve grooves S is occupied by the same branches a-l in each layer L.

[0040] In the exemplary embodiment of FIGS. 6 and 7, branches a-l of the same phases U, V, W are further arranged in four respective successive layers L of each groove S. For example, branches a, b, g, h of the first phase U, or branches c, d, i, j of the second phase V, or branches e, f, k, l of the third phase W are arranged in four respective successive layers L of each groove S. In this exemplary embodiment, two branches a-l of the same phases U, V, W each occupy four respective successive layers L of each groove S. Layers L1-L4 of the first groove S1 are occupied, for example, by the first branch a and the fourth branch h of the first phase U. Layers L5-L8 of the first groove S1 are occupied, for example, by the first branch e and the fourth branch l of the third phase W.

[0041] In the exemplary embodiment of FIGS. 6 and 7, two different branches a-l of the same phase U, V, W are arranged in two consecutive grooves S, respectively, in each layer L. The phases U, V, W change after each second groove S2 in each layer L. For example, in the first layer L1, the first branch a is arranged in the first groove S1, and the second branch b of the first phase U is arranged in the second groove S2. In contrast, the first layer L1 of the third groove S3 is occupied by the first branch c of the second phase V, and the first layer L1 of the fourth groove S4 is occupied by the second branch d of the second phase V. The first layer L1 of the fifth groove S5 is occupied by the first branch e of the third phase W, and the first layer L1 of the sixth groove S6 is occupied by the second branch f of the third phase W. As described above, the occupation of branches a-l of different phases U, V, W results in each layer L after each second groove S2.

[0042] The branches a-l thus occupy the groove structure 9 symmetrically in the circumferential direction 7. This means in particular that the stator 5 is at least doubly symmetric with respect to rotation around the central longitudinal axis 14 (see FIG. 2 ) of the stator 5. This therefore applies in particular to the arrangement of the branches a-l in the groove structure 9. As can be further seen in particular from FIG. 6 , in the case of the illustrated exemplary embodiment, the rotationally symmetric arrangement of the branches a-l in the groove structure 9 is also imparted to the through-flow of the branches a-l.

[0043] 6 it is therefore assumed that each branch a to l can be realised as a wave winding 15, where the suggested wave winding 15 is in each case shown superimposed in Fig. 6. The indicated wave winding 15 is thereby illustrated, purely by way of example, for the first branch c and the second branch d of the second phase U. Each wave winding 15 is thereby introduced radially into the groove structure 9.

[0044] Another exemplary embodiment of the stator 5 is shown in FIG. 8, which corresponds to the view of FIG. 7. In this embodiment, the branches a, b, g, and h of the first phase U are shown hatched or filled, respectively, and the first branch a of the first phase U is then shown filled. Thus, in this exemplary embodiment, each of the layers L1 to L8 of the groove structure 9 is also occupied at least once by the same branch a to l. In this exemplary embodiment, each of the layers L is also occupied four times by the same branch a to l. In this exemplary embodiment, the groove structure 9 is thereby symmetrically occupied in the circumferential direction 7 as well, being symmetrically occupied by the branches a to l. For example, the first branch a of the first phase U is arranged in the first groove S1 in the first layer L1, and in the eighth groove S8, the thirteenth groove S13, and the forty-fourth groove S44. In the exemplary embodiment of FIG. 8, each of the phases a to l can thereby be present as a so-called hairpin winding 16, introduced axially into the groove structure 9.

[0045] As can be seen from the figure, the conductors 1 in each case thereby have a rectangular cross section. The conductors 1 therefore abut flat against one another in the respective grooves S.

Claims

1. A stator (5) for an electric machine (2), comprising: A carrier body (11) extending in an axial direction (6) and a circumferential direction (7), The carrier body (11) has a groove structure (9), The groove structure (9) has a groove (S) that opens radially on one side and extends in the axial direction (6), The grooves (S) and the teeth (12) are arranged alternately and continuously in the circumferential direction, an electrical conductor (1) that generates a magnetic field when in operation and is placed in the groove (S); a total of eight radially consecutive layers (L) of the electrical conductor (1) are arranged in each groove (S), so that the groove structure (9) has a total of eight layers (L); The electrical conductors (1) are electrically interconnected in three phases (U, V, W), The groove structure (9) has a total of 48 grooves (S), Each phase (U, V, W) has a total of four branches (a to l) connected in parallel; Each of said branches (a to l) is arranged in at least two of said grooves (S), Each of said branches (a to l) is arranged at least once in each layer (L) of said groove structure (9), the branches (a-l) of the same phase (U, V, W) are arranged in four successive layers (L) in each groove (S); Each twelfth groove (S) is occupied by an identical branch (a-l) in each layer, Each branch (a to l) occupies each layer (L) four times 1. A stator for an electric machine, comprising:

2. The stator (5) has a total of eight poles 2. A stator for an electric machine according to claim 1.

3. Each of said branches (a-l) has at least two electrical conductors (1), The electrical conductors (1) are electrically connected in series with each other.

3. A stator for an electric machine according to claim 1 or 2.

4. The branches (a to l) are arranged symmetrically in the circumferential direction (7) in the groove structure (9).

4. A stator for an electric machine according to claim 1, wherein the stator is a stator for an electric machine.

5. In each layer (L), each of the branches (a to l) is arranged in four grooves (S), and between them, 11 grooves (S) are arranged in this layer (L) where the branches (a to l) are not present.

5. A stator for an electric machine according to claim 4.

6. Each of the two different branches (a-l) of the same phase (U, V, W) is placed in a corresponding layer (L) of two consecutive grooves (S).

6. A stator for an electric machine according to any one of claims 1 to 5.

7. Each of said electrical conductors (1) has a rectangular cross section 7. A stator for an electric machine according to any one of claims 1 to 6.

8. The electrical conductor (1) is arranged in a groove structure (9) as at least one wave winding (15).

8. A stator for an electric machine according to any one of claims 1 to 7.

9. The electrical conductors (1) are arranged in the groove structure (9) as hairpins (16) and are arranged alternately and successively in the circumferential direction (7).

9. A stator for an electric machine according to any one of claims 1 to 8.

10. A stator (5) for an electric machine according to any one of claims 1 to 9, and a rotor (8) arranged coaxially with the stator (5). An electric machine (2) characterized in that:

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