Sealing arrangement and use thereof

Abstract

Sealing arrangement comprising a busbar (1) with at least one electrical conductor (2.1, 2.2, 2.3,...) and a two-component component (3) comprising a carrier part (4) made of a tough, hard material and a sealing body (5) made of a rubber-elastic sealing material, which is materially bonded to the carrier part (4), wherein the sealing body (5) surrounds the electrical conductor (2.1, 2.2, 2.3,...) without adhesion and under elastic preload.

Description

Technical field

[0001] The invention relates to a sealing arrangement and its use. The sealing arrangement comprises a busbar with at least one electrical conductor and a two-component component comprising a support part made of a tough, hard material and a sealing body made of a rubber-elastic sealing material, which is bonded to the support part. The sealing body surrounds the electrical conductor without adhesion and under elastic preload, sealingly. The support part, viewed in cross-section, is essentially L-shaped, with an axial flange and a radial flange. The axial flange extends parallel to the electrical conductor and surrounds it at a radial distance. At least one inner sealing lip of the sealing body is arranged in the gap formed by the distance, sealingly surrounding the outer circumference of the electrical conductor without adhesion and under elastic preload. State of the art

[0002] Oil-cooled electric motors are being used in an increasing number of electric vehicles. These oil-cooled electric motors place higher demands on their sealing, especially with regard to the power electronics of other electrical components, such as the power electronics of an inverter.

[0003] Furthermore, electric vehicles utilize busbars, which comprise electrical conductors made of copper or aluminum sheets that are stamped and then bent to the desired dimensions. Due to the manufacturing process, these copper or aluminum sheets have a rectangular conductor cross-section, which is not ideal for standard sealing because the corners of the stamped sheets do not allow for robust compression of the sealing material used in standard gaskets.

[0004] For this reason, it is also state of the art that the rectangular conductors are overmolded with a medium-tight thermoplastic or thermosetting material. If necessary, the conductors are additionally bonded with an adhesive. However, this does not usually achieve a permanently good seal. The seal is only initially satisfactory and often shows leaks after a short period of use, especially when the sealing points are exposed to temperature fluctuations. This is due to the different coefficients of thermal expansion of the electrical conductors and the sealing materials surrounding the conductors. These different coefficients of thermal expansion of the two materials lead to increased mechanical stresses at the interfaces and thus to the leaks described above.

[0005] Furthermore, a disadvantage is that the electrical conductors and the seals surrounding them cannot be separated without damage. In the event of a repair, the entire unit, consisting of the electrical conductors and the seals, must be replaced, which is unsatisfactory in terms of environmental protection, responsible resource management, and economics.

[0006] A sealing arrangement and its use are known from DE 10 2018 109 863 A1.

[0007] The sealing arrangement comprises a busbar with at least one electrical conductor and a two-component component. The component consists of a carrier made of a tough, hard material and a sealing element made of a rubber-elastic sealing material, which is bonded to the carrier by a material bond. The sealing element surrounds the electrical conductor without adhesive bonding and seals under elastic preload. The problem of sealing electrical conductors with a rectangular cross-section has been identified. The previously known sealing arrangement attempts to solve this sealing problem by effectively relieving stress on the sealing element. Therefore, a functional separation between the force absorption and the actual sealing action of the multi-component seal is crucial.

[0008] The multi-component seal can be an injection-molded part made of various plastics, or it can be a single piece, so that in such a case there is no assembly effort required to mount or assemble the multi-component seal.

[0009] The sealing arrangement is used to seal a busbar for a vehicle's electrical system against a housing.

[0010] A busbar and an arrangement comprising such a busbar are known from US 2022278518 A1.

[0011] To seal an electrical conductor, it is connected to a support body, the support body comprising a seal made of a rubber-elastic material that seals around the conductor on its outer circumference with an annular sealing area. The known busbar is used in the field of e-mobility and, in particular, for sealing liquid media, and is intended to exhibit good performance characteristics over a long service life, even when the busbar is exposed to temperature fluctuations.

[0012] The support structure and the electrical conductor do not touch directly. A permanently elastic seal is positioned between the support structure and the conductor. Different coefficients of thermal expansion between the support structure and the conductor are always functionally compensated for by the seal. The risk of leakage in the transition area between the support structure and the conductor is eliminated due to their indirect connection via the rubber-elastic seal.

[0013] One way to connect the supporting body and the seal is to connect them by means of force-fit and / or form-fit connections.

[0014] Another sealing arrangement is known from WO 2022 / 033776 A1. This sealing arrangement comprises a seal for an electrical cable and can be used in automobiles. The seal is designed as a grommet with a through-channel, the grommet comprising inwardly facing sealing lips for sealing the electrical cable.

[0015] The grommet not only fits electrical conductors with a rectangular cross-section, but also electrical conductors with a round or oval cross-section. Description of the invention

[0016] The invention is based on the objective of further developing a sealing arrangement of the type mentioned above in such a way that the aforementioned disadvantages are avoided.

[0017] In particular, the sealing arrangement should exhibit consistently good performance characteristics over a long service life. Furthermore, the sealing lips should be functionally individualized, with their material properties being well-suited to their respective functions.

[0018] Electrical conductors and seals should be replaceable separately as needed and recyclable by type.

[0019] Furthermore, a use of the sealing arrangement will be demonstrated.

[0020] This problem is solved according to the invention by the features of claim 1 and claim 9. Advantageous embodiments of the sealing arrangement are referred to in the claims directly or indirectly related to claim 1.

[0021] To solve the problem, a sealing arrangement is provided, comprising a busbar with at least one electrical conductor and a two-component component, which includes a support part made of a tough, hard material and a sealing body made of a rubber-elastic sealing material, which is bonded to the support part, wherein the sealing body surrounds the electrical conductor without adhesion and under elastic preload, wherein the support part, viewed in cross-section, is essentially L-shaped, with an axial flange and a radial flange, wherein the axial flange extends parallel to the electrical conductor and surrounds it at a radial distance, wherein at least one inner sealing lip of the sealing body is arranged in the gap formed by the distance, which surrounds the outer circumference of the electrical conductor without adhesion and under elastic preload.wherein the inner and outer sealing lips are each manufactured separately and positioned so as not to touch each other, and wherein at least the inner sealing lip consists of an electrically insulating sealing material. The sealing body of the two-component component can be made of a conventional rubber-elastic sealing material. Rubber-elastic sealing materials are readily available in many specifications at low cost, making the overall sealing arrangement simple and inexpensive to manufacture. The sealing body surrounds the electrical conductor without adhesion and seals under elastic preload. Therefore, the sealing body and electrical conductor can be replaced separately if necessary. The virtually unlimited reusability of the electrical conductor, which is made of an expensive material and is subject to practically no wear during its service life, is a particularly noteworthy advantage.

[0022] The support body, viewed in cross-section, is essentially L-shaped, with an axial flange and a radial flange, wherein the axial flange extends parallel to the electrical conductor and surrounds it at a radial distance, wherein at least one inner sealing lip of the sealing body is arranged in the gap formed by the distance, which surrounds the outer circumference of the electrical conductor without adhesion and under elastic preload.

[0023] Preferably, two internal sealing lips arranged in a functional series circuit can be used to further increase the sealing reliability.

[0024] The inner and outer sealing lips are manufactured separately and positioned so as not to touch each other. This design offers the advantage that the inner and outer sealing lips can each be functionally customized. The material properties of the sealing lips can be precisely tailored to their respective functions.

[0025] In an advantageous embodiment, the support body can be made of a tough, rigid plastic, preferably electrically insulating. The advantage here is that the two-component component is easy and inexpensive to manufacture and has a low weight. The electrically insulating properties of the support part eliminate the need for separate electrical insulation from a housing to which the two-component component is typically attached.

[0026] At least one outer sealing lip can be arranged on the side of the axial flange radially opposite the inner sealing lip. This outer sealing lip seals against a housing to which the two-component component is attached.

[0027] The inner sealing lip and the outer sealing lip preferably consist of an electrically insulating sealing material. Particularly when the support part is also made of an electrically insulating material, the electrical conductors of the busbar and a housing to which the two-component component is attached are effectively electrically isolated from each other.

[0028] At least the inner sealing lip can be made of an electrically insulating sealing material. If the electrical conductor is sealed by the inner sealing lip, and the inner sealing lip prevents contact with the support part, it is not absolutely necessary for the outer sealing lip to also be made of an electrically insulating sealing material. Sealing materials that do not have a particularly high electrical resistance but provide a particularly durable and reliable seal can also be used, for example, because they are particularly oil-resistant.

[0029] Additional sealing of the two-component component against the housing to which it is fixed can be achieved by providing the radial flange with at least one axial sealing lip that extends axially towards the outer sealing lip and substantially along the outer circumference of the support part. In such a case, the sealing of the two-component component is achieved through the interaction of the axial sealing lip and the outer sealing lip. The axial sealing lip and the outer sealing lip seal an opening in a housing, in which the two-component component is located, against the environment.

[0030] According to an advantageous embodiment, the electrical conductor can have a round or oval cross-section. The advantage here is that, unlike an electrical conductor made of stamped sheet metal, it has no corners or process-related stamping burrs, thus enabling robust compression of the sealing material. The round or oval cross-section of the electrical conductor does not damage the inner sealing lip, even under higher elastic preloads.

[0031] The support component can have at least one mounting hole in which a force-limiting element is located. The support component can, for example, be screwed onto a housing. For this purpose, a screw first penetrates the mounting hole and is screwed into the housing. To prevent damage to the support component when screwing it onto the housing due to excessive tightening torque of the screw, force-limiting elements, which can be formed, for example, by force-limiting rings, are provided. This prevents an undesirably high force that could otherwise lead to the destruction of the support component.

[0032] Furthermore, the sealing arrangement can comprise a liquid-cooled electrical component with a housing, wherein the housing has an installation opening in which the two-component component is arranged in a sealing manner.

[0033] The electrical component can be formed by an electric motor.

[0034] As already described at the beginning, it is particularly necessary in oil-cooled electric motors in electric vehicles to safely seal sensitive power electronics, for example the power electronics of an inverter.

[0035] Furthermore, the invention relates to the use of a sealing arrangement, as previously described, for sealing a current busbar of a liquid-cooled electrical component.

[0036] The sealing arrangement described above is simple and inexpensive to manufacture. In the event of a repair, the electrical conductor can always be reused due to the non-adhesive connection between the conductor and the inner seal. To do this, the conductor is simply pulled out of the inner seal, the existing support part with the existing sealing element (i.e., the two-component component) is replaced with a corresponding new pre-assembled unit, and the conductor is then reinstalled in the sealing element.

[0037] The sealing assembly also features a low-parts design. Assembly is reliably performed because separately manufactured sealing rings are not required. Brief description of the drawing

[0038] An embodiment of the sealing arrangement according to the invention is described below with reference to the Figure 1 and 2 explained in more detail.

[0039] These show, in schematic representation: Figure 1 shows a section of an embodiment of a sealing arrangement in a perspective view, Figure 2 shows a section through the sealing arrangement. Figure 1 . Implementation of the invention

[0040] In the Figure 1 and 2 Figure 1 shows an embodiment of a sealing arrangement according to the invention.

[0041] In this embodiment, the busbar 1 comprises three electrical conductors 2.1, 2.2, 2.3, each with a circular cross-section. The electrical conductors 2.1, 2.2, 2.3 are enclosed by the two-component component 3, which comprises the support part 4 and the sealing element 5. In this embodiment, the support part 4 consists of a tough, electrically insulating plastic, and the sealing element 5 of a rubber-elastic sealing material. The support part 4 and the sealing element 5 form a pre-assembled unit and are bonded together. The schematically indicated liquid-cooled electrical component 14 is formed by an oil-cooled electric motor for an electric vehicle and comprises the housing 15, which has an installation opening 16 for the two-component component 3. The two-component component 3 is arranged in a sealing manner in the installation opening 16 of the housing 15. The two-component component 3 is screwed to the housing 15.The two mounting holes 12.1, 12.2 are arranged in the support part 4, each containing an annular force-limiting element 13.1, 13.2, which is made, for example, of a metallic material. This protects the comparatively sensitive material of the support part 4 from excessive tightening torques that could damage the support part 4 during its assembly on the housing 15.

[0042] In Figure 2 The sealing arrangement is made of Figure 1The section shown illustrates that the support body 4, viewed in cross-section, is essentially L-shaped and has an axial flange 6 and a radial flange 7. The axial flange 6 extends parallel to the electrical conductors 2.1, 2.2, 2.3, and the radial flange 7 perpendicular to them. The axial flange 6 is essentially completely enclosed by the sealing material of the sealing body 5, internally by the inner sealing lips 9.1, 9.2 and externally by the outer sealing lip 10.

[0043] In the illustrated embodiment, the inner sealing lips 9.1, 9.2 and the outer sealing lip 10 merge seamlessly and are made of the same electrically insulating sealing material. For most applications, such a seamless, material-uniform design is well-suited and easy and cost-effective to manufacture.

[0044] The axial sealing lip 11, which is also integrally formed and made of the same material as the outer sealing lip 10 and the inner sealing lips 9.1, 9.2, is arranged on the radial flange 7 of the support part 4 and is axially protruded in a bead-like shape towards the outer sealing lip 10. The axial sealing lip 11 seals the end face of the housing 15, while the outer sealing lip 10 seals the circumferential boundary of the installation opening 16.

[0045] The sealing element 5 encloses the electrical conductors 2.1, 2.2, 2.3 without adhesive bonding and sealing under elastic preload. If necessary, the electrical conductors 2.1, 2.2, 2.3 can therefore be easily and non-destructively removed from the sealing element 5.

Claims

1. Sealing arrangement comprising a busbar (1) with at least one electrical conductor (2.1, 2.2, 2.3,...) and a two-component component (3) comprising a support part (4) made of a tough, hard material and a sealing element (5) made of a rubber-elastic sealing material, which is bonded to the support part (4) in a material-bonded manner, wherein the sealing element (5) surrounds the electrical conductor (2.1, 2.2, 2.3,...) without adhesion and under elastic preload, wherein the support part (4), viewed in cross-section, is substantially L-shaped, with an axial flange (6) and a radial flange (7), wherein the axial flange (6) extends parallel to the electrical conductor (2.1, 2.2, 2.3,...) and surrounds it at a radial distance, wherein at least one inner sealing lip (9.1, 9.2,...) of the sealing body (5) is arranged, which surrounds the outer circumference of the electrical conductor (2.1, 2.2, 2.3,...) non-adherent and sealingly enclosed under elastic preload, . characterized by the fact that the inner sealing lip (9.1, 9.2,...) and the outer sealing lip (10) are each produced separately from each other and are assigned to each other in a non-contacting manner, and that at least the inner sealing lip (9.1, 9.2,...) consists of an electrically insulating sealing material.

2. Sealing arrangement according to claim 1, characterized by the fact that the supporting body (4) consists of an electrically insulating plastic.

3. Sealing arrangement according to one of claims 1 or 2, characterized by the fact that on the side of the axial flange (6) facing radially away from the inner sealing lip (9.1, 9.2,...) at least one outer sealing lip (10) is arranged.

4. Sealing arrangement according to one of claims 1 to 3, characterized by the fact that the radial flange (7) has at least one axial sealing lip (11) which extends axially in the direction of the outer sealing lip (10) and substantially along the outer circumference of the support part (4).

5. Sealing arrangement according to one of claims 1 to 4, characterized by the fact that the electrical conductor (2.1, 2.2, 2.3,...) has a round or oval cross-section.

6. Sealing arrangement according to one of claims 1 to 4, characterized by the fact that the support part (4) has at least one fastening bore (12.1, 12.2,...) in which a force limiting element (13.1, 13.2,...) is arranged.

7. Sealing arrangement according to one of claims 1 to 6, characterized by the fact that this also comprises a liquid-cooled electrical component (14) with a housing (15), wherein the housing (15) has an installation opening (16) in which the two-component component (3) is arranged in a sealing manner.

8. Sealing arrangement according to claim 7, characterized by the fact that the electrical component (14) is formed by an electric motor.

9. Use of a sealing arrangement according to one of claims 1 to 8 for sealing a busbar (1) of a liquid-cooled electrical component (14).

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