Stator, electric motor, rotary transformer, and production method

Abstract

The invention relates to a stator (1) for an electric motor (2), comprising an electric coil (3), a housing (4), the interior of which contains the coil (3) and the exterior of which has electrical connections (5) for controlling the coil (3) and / or for supplying energy to the coil (3), and electric cables (6), which are led through a housing opening (7) and electrically connect the coil (3) to the connections (5). The interior of the housing (4) is potted with a potting compound (8), in which the coil (3) is embedded. A simplified production process is provided if the housing opening (7) is closed by means of a separate closure plate (9) having a cable opening (10) for each cable (6), one of the cables (10) being guided through each cable opening (10), and if the potting compound (8) bears against the closure plate (9) inner face (11) facing the coil (3) and encloses the cables (6) from the coil (3) to the closure plate (9).

Description

[0001] Stator, electric motor, rotary transformer and manufacturing process

[0002] The present invention relates to a stator for an electric motor, an electric motor equipped with such a stator, and a rotary transformer equipped with such a stator. The invention also relates to a method for manufacturing such a stator.

[0003] An electric motor designed as a rotating machine has a motor stator and a motor rotor, which is rotatably mounted about an axis of rotation relative to the motor stator. In an electric motor configured as an inductively separately excited synchronous machine, the electric motor has a rotary transformer, which includes a transformer stator fixed to the motor stator and a transformer rotor fixed to the motor rotor. The motor stator has a stator coil. The transformer stator has a stationary primary coil.

[0004] In the present context, a “configuration” corresponds to a “design” and / or a “setup”, so that the phrase “configured so that” is synonymous with the phrase “designed so that” and / or “set up so that”.

[0005] Regardless of whether the stator is a motor stator or a transformer stator, each stator has an electrical coil and a housing that contains the coil internally and has external electrical connections for controlling and / or powering the coil. Electrical cables are also provided to connect the coil to these connections. The housing can be advantageously lined internally with a potting compound in which the coil is embedded.

[0006] Rotary transformers for such synchronous machines are known, for example, from US 2021 / 0 358 686 A1, from DE 10 2021 213294 A1 and from DE 102021 212 152 A1.

[0007] From DE 10 2014 016 891 A1, a cable routing is known which can be fixed in a housing opening, which has two interconnectable modules, each of which has recesses which, in the interconnected modules, combine to form two passage openings for each cable, wherein a seal is inserted into each passage opening which encloses the respective cable within the passage opening.

[0008] For potting the housing, a potting compound with a very low viscosity in its liquid state is used, allowing it to completely fill the housing and fully encase the coil. A disadvantage of this method is the need for complex sealing of the housing to prevent the liquid potting compound from leaking out during the pouring process. A housing opening through which cables are routed to electrically connect the internal coil to the external terminals can be particularly critical.

[0009] The present invention addresses the problem of providing an improved or at least a different embodiment for a stator of the type described above, or for an electric motor equipped therewith, or for a rotary transformer equipped therewith, or for an associated manufacturing process, which is characterized in particular by a simplification in the casting of the housing with the potting compound.

[0010] This problem 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 invention is based on the general concept of closing the opening of a stator, in which the electrical cables pass through a housing opening, with a separate sealing plate. The sealing plate has a cable opening for each cable, through which one of the cables passes. When the housing is filled with potting compound, the compound can penetrate as far as the sealing plate. However, since the sealing plate closes the housing opening and the cable openings are sealed by the cables, leakage or escape of the potting compound through the housing opening is prevented. This simplifies the manufacture of the stator and the electric motor equipped with it. It is noteworthy that the sealing plate acts almost like a casting core that remains on or in the casting after the casting process, thus constituting a so-called lost casting core.

[0012] Specifically, the invention proposes a stator for an electric motor comprising an electrical coil, a housing containing the coil internally and featuring external electrical connections for controlling and / or powering the coil, and several electrical cables that pass through a housing opening and electrically connect the coil to the terminals. The housing is lined internally with a potting compound in which the coil is embedded. The housing opening is closed by a separate sealing plate, which has a cable opening for each cable, through which one of the cables passes, in particular such that the respective cable opening is closed by the respective cable passing through it. The potting compound rests against an inner surface of the sealing plate facing the coil and encloses the cables from the coil to the sealing plate.The potting compound is typically formulated to adhere to the surfaces it comes into contact with during the potting process. This means the potting compound adheres to the outside of the cables, the outside of the coil, the inside of the housing, and the inside of the cover plate.

[0013] During stator manufacturing, the sealing plate simultaneously serves to position the cables, as the cables, which pass through the cable openings, are positioned relative to the housing by the sealing plate located in the housing opening before being potted with the potting compound. According to an advantageous embodiment, the housing can have a step at the housing opening that extends laterally along the opening and against which the sealing plate rests on its outer side facing away from the coil. This allows the sealing plate to be supported by the step, particularly during the potting process, and to reliably close the housing opening.

[0014] According to an advantageous embodiment, the housing can have a groove at the housing opening that extends laterally along the housing opening and into which the sealing plate engages at its edge. The groove has two opposing groove walls and a groove base that connects the two groove walls. One of the two groove walls expediently forms the step against which the sealing plate rests at its outer edge. Before the housing is potted with the potting compound, the groove facilitates the attachment of the sealing plate to the housing, thus simplifying assembly.

[0015] In an advantageous embodiment, the cover plate can be divided into two plate sections along a dividing line. This dividing line runs through the cable openings, so that each cable opening is divided into two opening sections. Accordingly, each plate section has one of the opening sections for each cable opening. This simplifies assembly, as one plate section can first be positioned in the housing opening, and then the cables can be inserted into the opening sections of that plate section. The other plate section can then be mounted, thus completing the cable openings and routing the cables through them.

[0016] Advantageously, the cable openings within the closure plate are arranged side by side along a straight line. Advantageously, the dividing line is configured as a straight line. Advantageously, the dividing line is such that the cable openings are bisected, so that each opening section represents half a cable opening, enclosing the respective cable by 180°. According to an advantageous embodiment, the closure plate can have a circumferential outer seal along its edge, which abuts the housing to provide a seal. The outer seal can be configured elastically so that it is elastically deformed when the closure plate is inserted into the housing opening. This causes the outer seal to be pre-tensioned against the housing, thus improving the sealing effect. In particular, it can be provided that the outer seal abuts the bottom of the aforementioned groove. In the case of a split closure plate, the outer seal extends proportionally across both plate sections.

[0017] In another embodiment, the sealing plate can have a circumferential inner seal in each cable opening, which abuts the respective cable to provide a seal. Advantageously, the respective inner seal can be designed to be elastic. When a cable passes through the respective cable opening, the respective inner seal can be elastically deformed. This allows the respective inner seal to be pre-tensioned against the respective cable. In the case of a split sealing plate, the respective inner seal extends partially within the respective opening section.

[0018] In an advantageous embodiment, the housing opening can be arranged or oriented radially at an axial housing end, so that the housing opening is axially open laterally at the housing end. This simplifies assembly.

[0019] According to an advantageous embodiment, the stator can form a motor stator of the electric motor, which has a motor rotor that is rotatable about an axis of rotation relative to the motor stator. The coil of the stator or motor stator is then designed as a stator coil.

[0020] Alternatively, the stator can form the transformer stator of a rotary transformer, which has a transformer rotor that is rotatable about an axis of rotation relative to the transformer stator. The coil of the stator or transformer stator is then designed as the stationary primary coil of the rotary transformer. The rotary transformer is used in an electric motor designed as an inductively electrically separately excited synchronous machine to supply a rotor coil with electrical energy or to control the rotor coil.

[0021] An electric motor according to the invention has a motor stator and a motor rotor which is rotatable about an axis of rotation with respect to the motor stator, wherein the motor stator is designed as a stator of the type described above.

[0022] A rotary transformer according to the invention has a transformer stator and a transformer rotor which is rotatable about an axis of rotation with respect to the transformer stator, wherein the transformer stator is designed as a stator of the type described above.

[0023] Another electric motor according to the invention comprises a motor stator, a motor rotor rotatable about an axis of rotation with respect to the motor stator, and a rotary transformer of the aforementioned type.

[0024] An inventive method for manufacturing a stator of the type described above comprises, in a first step, inserting the coil into the housing, inserting the sealing plate into the housing opening, and guiding the cables through the cable openings. In a second step, the inside of the housing is filled with the potting compound. Since the sealing plate closes the housing opening and the cables close the cable openings, the potting compound remains inside the housing.

[0025] According to an advantageous embodiment using the split closure plate, the first step comprises additional sub-steps. First, only one or the first plate section is inserted into the housing opening. Then, the cables are inserted laterally into the openings of the first plate section. Next, the other or second plate section is inserted into the housing opening, with the openings of the second plate section aligning laterally with the cables, thus completing the cable openings. Following this, the cables are guided through the cable openings. If the housing has an axially open end face, this open end is closed with a suitable tool before being potted with the potting compound.If the housing opening is located at this axial housing end and configured as a radial housing opening, the housing opening can be axially open laterally at the housing end. This axially open side of the housing opening is also closed with the tool, with the sealing plate bearing against the tool. Advantageously, the outer seal of the sealing plate can also seal against the tool.

[0026] Further important features and advantages of the invention will become apparent from the dependent claims, the drawings and the associated description of the figures based on the drawings.

[0027] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention. Components of a higher-level unit, such as a device, apparatus, or arrangement, mentioned above and those to be mentioned below, which are designated separately, can form separate parts or components of this unit or be integral areas or sections of this unit, even if this is depicted differently in the drawings.

[0028] Preferred embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein identical reference numerals refer to identical or similar or functionally identical components.

[0029] They show, schematically,

[0030] Figure 1 is an isometric view of a stator in the area of ​​a housing opening, Figure 2 is an isometric view of a plate part of a closure plate for closing the housing opening,

[0031] Figure 3 shows a flowchart of a process for manufacturing such a stator.

[0032] As shown in Figure 1, a stator 1 of an electric motor 2 (only partially shown) comprises an electrical coil 3, which is not visible in Figure 1, and a housing 4. The housing contains the coil 3 internally and has electrical terminals 5 on the outside, which are symbolically indicated by circles in Figure 1. The terminals 5 serve to control the coil 3 and / or to supply it with electrical power. The stator 1 also has at least two electrical cables 6, which pass through an opening 7 in the housing 4 and electrically connect the coil 3 to the terminals 5. The housing 4 is lined internally with a potting compound 8. The coil 3 is completely enclosed by the potting compound 8, so that the coil 3 is embedded in the potting compound 8.

[0033] The stator 1 presented here also has a cover plate 9, which represents a separate component with respect to the housing 4 and may, in particular, be made of a different material than the housing 4. Advantageously, the cover plate 9 is made of a plastic. The housing 4 may be made of a metal or of a plastic, in particular of a different plastic than the cover plate 9. The cover plate 9 has a separate cable opening 10 for each cable 6, through which one of the cables 6 is passed. The potting compound 8 is cast into the housing 4 such that the potting compound 8 rests against an inner surface 11 of the cover plate 9 facing the coil 3 and encloses the cables 6 from the coil 3 to the cover plate 9.The cables 6 have cable sections running inside the housing 4, which are connected to the coil 3. These cable sections are encased by the potting compound 8 and are not visible in Figure 1. The potting compound 8 can be, in particular, a highly adhesive resin, so that it adheres to essentially all components with which it comes into contact during potting, thus forming a material bond. The potting compound 8 is therefore materially bonded to the inner surface 11 of the cover plate 9. Likewise, the potting compound 8 is materially bonded to the coil 3 and to the cable sections 6 running within it. After the potting compound 8 has cured, a positive connection is also formed.

[0034] As shown in Figure 1, the housing 4 has a step 12 in the area of ​​the housing opening 7, which extends laterally along the housing opening 7. In the illustration of Figure 1, the step 12 extends along the housing opening 7 in a substantially U-shape. The sealing plate 9 rests against the edge of the step 12 on an outer surface 13 facing away from the coil 3. In other words, the sealing plate 9 is directed away from the coil 3, i.e., supported outwards by the step 12.

[0035] In the example shown in Figure 1, the housing 4 has a groove 14 in the area of ​​the housing opening 7. This groove extends laterally along the housing opening 7, and the end plate 9 engages in it at its edge. In the view shown in Figure 1, the groove 14 extends in a U-shape along the housing opening 7. The groove 14 has two groove walls 15, 16, which are opposite each other and run parallel to one another. The groove 14 also has a groove base 17, which connects the two groove walls 15, 16. The groove wall 15 facing away from the coil 3 forms the step 12 mentioned above, against which the end plate 9 rests at its outer edge 13. To enable the end plate 9 to be inserted into the groove 14, the housing opening 7, as shown in Figure 1, can be arranged at an axial housing end 18 and configured as a radial housing opening 7. The axial housing end 18 is designed to be axially open.The housing opening 7 is arranged at the axial housing end 18 such that it is axially open laterally at this housing end 18. This gives the housing opening 7 an axially open side 19 that extends along the housing end 18. The closing plate 9 can be axially inserted into the groove 14 through this open side 19.

[0036] The closure plate 9 is divided into two plate parts 21, 22 along a dividing line 20, as shown in Figure 1. The dividing line 20 advantageously extends through the cable openings 10, so that the cable openings 10 are also each divided into two opening parts 23, which are only labelled in Figure 2. Each plate part 21, 22 has one of the two opening parts 23 for each cable opening 10. An embodiment is particularly advantageous in which the closure plate 9, the cable openings 10, and the dividing line 20 are coordinated such that the two plate parts 21, 22 are structurally identical. One of the two plate parts 21, 22 is shown in Figure 2. If the two plate parts 21, 22 are structurally identical, the descriptions in Figure 2 apply equally to both plate parts 21, 22.

[0037] As shown in Figure 2, the closure plate 9 has a circumferential seal 24 along its edge, which, when installed, abuts the housing 4 to form a seal. The outer seal 24 can be configured to be elastically deformable. It can be configured as a lamellar seal or a sealing lip. The outer seal 24 preferably runs completely around the edge of the closure plate 9, i.e., over a 360° circumference. In the split embodiment, the outer seal 24 extends proportionally along the edge of each of the two plate parts 21, 22 over a 180° radius. According to an advantageous embodiment, the closure plate 9 can be configured rectangularly to achieve a simple geometry. The plate parts 21, 22 are then also configured rectangularly. The outer seal 24 then extends rectangularly along the closure plate 9, while it extends in a U-shape along the plate parts 21, 22.When the closure plate 9 is installed, the outer seal 24 rests against the groove base 17 inside the groove 14.

[0038] As shown in Figure 2, the closure plate 9 can have a circumferential inner seal 25 in each cable opening 10. In the assembled state, i.e., with the cable 6 passed through the respective cable opening 10, the inner seal 25 rests against the respective cable 6, sealing it. The inner seal 25 can also be configured elastically. In the assembled state, it can be elastically deformed and thus pre-tensioned against the respective cable 6. The inner seal 25 can be configured as a sealing lip or a lamellar seal. In the example shown in Figure 1, the cables 6 each have a circular outer cross-section. Accordingly, the cable openings 10 also have a complementary circular inner cross-section. The circumferential inner seal 25 then also extends circularly over 360°. In the case of the split closure plate 9, the opening sections 23 each extend over 180°.Accordingly, the respective inner seal 25 extends proportionally within the respective partial opening 23, i.e. also over 180°.

[0039] Advantageously, the stator 1 can be a motor stator of the electric motor 2, wherein the electric motor 2 has a motor rotor (not shown) that is rotatable about an axis of rotation (not shown) relative to the motor stator. The coil 3 of the motor stator 1 then forms a stator coil of the electric motor 2. Alternatively, the stator 1 can also be configured as a transformer stator of a rotary transformer 26, which has a transformer rotor (not shown) that is rotatable about an axis of rotation (not shown) relative to the transformer stator 1. The rotary transformer 26 can be used with an electric motor 2 if this electric motor 2 is configured as an inductively electrically separately excited synchronous machine. The rotary transformer 26 serves to supply energy to a rotor coil (not shown) of the electric motor 2. The coil 3 of the transformer stator then forms a stationary primary coil of the rotary transformer 26.

[0040] According to Figure 3, a method 27 for manufacturing the stator 1 comprises a step 28 in which the coil 3 is inserted into the housing 4 and the sealing plate 9 into the housing opening 7, and the cables 6 are passed through the cable openings 10. In a subsequent step 29, the inside of the housing 4 is filled with the potting compound 8. If, as proposed here, a split sealing plate 9 is used, step 28 can additionally comprise several sub-steps. In step 28.1, only one or the first plate part 21 is inserted into the housing opening 7. In step 28.2, the cables 6 are inserted laterally into the opening sections 23 of the first plate part 21 inserted into the housing opening 7. In step 28.3, the other or second plate part 22 is inserted into the housing opening 7.The opening sections 23 of the second plate section 22 complete the cable openings 10, so that the cables 6 are subsequently guided through the cable openings 10. If, as shown in Figure 1, the housing opening 7 at the axial housing end 18 is arranged such that it has an axially open side 19, then, after the cables 6 have been guided through the cable openings 10 of the closure plate 9 in step 28 and before the potting compound 8 has been poured in step 29, the axially open housing end 18, including the open side 19 of the housing opening 7, can be axially closed in a further step 30 or intermediate step 30 using a suitable tool. The closure element 9 is dimensioned such that it rests axially against this tool. In particular, the outer seal 24 then seals against the tool.In the subsequent casting process according to step 29, the potting compound 8 can only spread within the housing 4 as far as the closing plate 9. The tool is expediently configured so that it does not form a material bond with the potting compound 8, allowing it to be easily removed.

[0041] Reference numeral list Stator Electric motor Coil Housing Connection Cable Housing opening Potting compound Sealing plate Cable opening Inside Step Outside Groove Groove wall Groove wall Groove base Housing end Open side Dividing line Plate part Plate part Opening part Outer seal Inner seal Rotary transformer Procedure Step Step Step

Claims

Patent claims 1. Stator (1) for an electric motor (2), - with an electrical coil (3), - with a housing (4) which contains the coil (3) inside and which has electrical connections (5) on the outside for controlling the coil (3) and / or for supplying power to the coil (3), - with electrical cables (6) which are passed through a housing opening (7) and electrically connect the coil (3) to the terminals (5), - wherein the housing (4) is lined internally with a potting compound (8) in which the coil (3) is embedded, - wherein the housing opening (7) is closed with a separate closing plate (9) which has a cable opening (10) for each cable (6) through which one of the cables (10) is passed, - wherein the potting compound (8) is located on an inner surface (11) of the closure plate (9) facing the coil (3) and surrounds the cables (6) from the coil (3) to the closure plate (9).

2. Stator (1) according to claim 1, characterized in that, - that the housing (4) has a step (12) at the housing opening (7) which extends laterally along the housing opening (7) and against which the closing plate (9) rests on its outer side (13) facing away from the coil (3).

3. Stator (1 ) according to claim 2, characterized in that, - that the housing (4) has a groove (14) at the housing opening (7) which extends laterally along the housing opening (7) and into which the closing plate (9) engages at its edge, - that the groove (14) has two groove walls (15, 16) and a groove base (17) connecting the groove walls (15, 16) together, - that one of the groove walls (15) forms the step (12) against which the closure plate (9) rests on its outer side (13) at the edge.

4. Stator (1) according to one of the preceding claims, characterized in that - that the closure plate (9) is divided along a dividing line (20) into two plate parts (21, 22) is divided, - that the dividing line (20) runs through the cable openings (10), so that the cable openings (10) are each divided into two opening parts (23), - that each plate part (21 , 22) of each cable opening (10) has one of the opening parts (23).

5. Stator (1) according to one of the preceding claims, characterized in that - that the closure plate (9) has a circumferential outer seal (24) along its edge, which seals against the housing (4).

6. Stator (1 ) according to claims 3 and 5, characterized in that, - that the outer seal (24) rests against the base of the groove (17).

7. Stator (1) according to one of the preceding claims, characterized in that - that the sealing plate (9) in each cable opening (10) has a circumferential inner seal (25) which seals against the respective cable (6).

8. Stator (1) according to one of the preceding claims, characterized in that 16 - that the housing opening (7) is arranged radially at an axial housing end (18) so that the housing opening (7) is axially open laterally at the housing end (18).

9. Stator (1) according to one of the preceding claims, characterized in that - that the stator forms a motor stator (1 ) of the electric motor (2) which has a motor rotor which is rotatable about an axis of rotation with respect to the motor stator (1 ), - that the coil is designed as the stator coil (3) of the electric motor (2).

10. Stator (1 ) according to one of claims 1 to 8, characterized in that, - that the stator forms a transformer stator (1 ) of a rotary transformer (26) which has a transformer rotor which is rotatable about an axis of rotation with respect to the transformer stator (1 ), - that the coil is designed as a stationary primary coil (3) of the rotary transformer (26).

11. Electric motor (2) with a motor stator and a motor rotor rotatable about an axis of rotation with respect to the motor stator, wherein the motor stator is formed by a stator (1) according to one of the preceding claims.

12. Rotary transformer (26) comprising a transformer stator and a transformer rotor rotatable about an axis of rotation with respect to the transformer stator, wherein the transformer stator is formed by a stator (1) according to one of the preceding claims.

13. Electric motor (2) comprising a motor stator, a motor rotor rotatable about an axis of rotation with respect to the motor stator, and a rotary transformer (26) according to claim 12. 17 14. Method (27) for manufacturing a stator (1 ) according to any one of claims 1 to 10, - in which the coil (3) is inserted into the housing (4) and the closing plate (9) into the housing opening (7) and the cables (6) are passed through the cable openings (10), - in which the housing (4) is filled inside with the potting compound (8).

15. Method (27) according to claim 14, characterized in that - that initially only the one plate part (21 ) is inserted into the housing opening (7), - that the cables (6) are inserted laterally into the opening parts (23) of one plate part (21), - that afterwards the other plate part (22) is inserted into the housing opening (7) such that the opening parts (23) of the other plate part (22) complete the cable openings (10) and the cables (6) are passed through the cable openings (10).

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