CONTACT ELEMENT FOR ELECTRICAL CONTACTING OF AN ELECTRICAL CONDUCTOR TO A CONNECTION PART OF AN ELECTRICAL SYSTEM AND METHOD FOR ITS MANUFACTURING

Description

[0001] The invention relates to a contact element for electrically connecting an electrical conductor to a terminal of an electrical system, in particular an electrical system of a motor vehicle, comprising the electrical conductor, which is sheathed with conductor insulation, and a cable lug with a contact part connected to the electrical conductor in an electrically conductive manner, wherein the cable lug and an adjoining section of the electrical conductor are overmolded with an electrically insulating housing such that a portion of the contact part is exposed, and wherein the housing has a channel extending from an opening in the housing to the exposed portion of the contact part. Such a contact element can be used, for example, to create a watertight screw connection between an electrical conductor and a terminal of an electrical system.

[0002] To create a watertight connection between an electrical conductor and a terminal, housings are available on the market that are fitted onto the conductor and an attached cable lug. To achieve a watertight seal between the conductor and the housing, a single-core seal is typically inserted into the housing. While a watertight connection can be achieved in this way, the installation of these housings is quite complex and requires considerable installation space.

[0003] Furthermore, DE 10 2013 021 409 A1 discloses a contact element for connecting an electrical conductor to a terminal. Access to the contact element is provided by a channel in the housing, allowing the contact element to be screwed onto a terminal of an electrical device through the channel using a screw. The channel can then be sealed by screwing in or snapping on a sealing cap. DE 10 2013 021 409 A1 proposes overmolding the cable lug with the housing material. While this saves assembly effort and installation space, it has proven difficult to produce a watertight housing using this method.

[0004] DE 10 2014 216762 A1 and DE 10 2016 100978 A1 each disclose a contact element according to the preamble of claim 1.

[0005] In particular, it has been found within the scope of the present invention that sealing a channel of an overmolded housing around a cable lug by screwing in or snapping on a sealing cap can be insufficient in some cases. Specifically, the materials available for overmolding a cable lug are not optimal for achieving the mechanical properties required for the housing to ensure a reliable seal.

[0006] Against this background, the present invention is based on the objective of providing an improved contact element for electrically contacting an electrical conductor to a connection part of an electrical system and a method for its manufacture, with which a reliable seal can be achieved in a cost-effective manner and with the smallest possible installation space.

[0007] This problem is solved according to the invention by a contact element according to claim 1.

[0008] Injection molding of a sealing element ensures sufficient adhesion between the housing and the sealing element. Furthermore, the material selection for the sealing element can be tailored to the specific sealing requirements, particularly for a reliable seal between the housing and a closure, especially a lid, to close the opening.

[0009] The above-mentioned problem is further solved procedurally by a method according to claim 10 for manufacturing the contact element according to claim 1.

[0010] The cable lug is electrically conductive and connected to the electrical conductor, particularly to one end of the conductor. For this purpose, the cable lug preferably has a connection area for connecting to an electrical conductor.

[0011] The connection between the cable lug and the electrical conductor can, for example, be a welded joint, in particular an ultrasonic welded joint. For this purpose, the connection area can be designed, for example, as a flat area to which the electrical conductor is welded. To improve the welded joint, a metallic contact layer can be applied to the contact area, for example by friction coating, in particular as described in DE 10 2014 011 887 A1.

[0012] Furthermore, the cable lug may be crimped to the electrical conductor.

[0013] The electrical conductor is in particular a cable, preferably a stranded conductor, for example with copper strands or aluminum strands.

[0014] The cable lug has a contact part. This contact part is, in particular, the part of the cable lug designed to connect to a terminal of an electrical system. Preferably, the contact part has a flat shape with a recess for inserting a connecting element to join the contact part to a terminal.

[0015] The cable lug can be completely flat, so that the contact part and the connection area are essentially in the same plane. However, the connection area can also be in a different plane than the contact part. For example, an angled cable lug can be used.

[0016] The housing has a channel that runs from an opening in the housing to the exposed part of the contact element. This provides external access to the exposed part of the contact element, allowing it to be connected to a terminal of an electrical system. The housing may, in particular, have a nozzle in which the channel is formed.

[0017] A sealing element is molded onto the housing to seal a closure used to close the opening. This sealing element ensures a reliable seal when the opening is closed with a suitable closure, such as a cover or a part of the connecting component, like a base that can be inserted into the duct, preventing water from entering the duct. The sealing element can be located within the duct, for example, in the area of ​​the opening. Alternatively, the sealing element can be molded onto the housing in the area around the opening. If the housing has a connection to the duct, the sealing element can be molded into or onto the connection.

[0018] The sealing element can be designed, in particular, for radial and / or axial sealing, relative to the direction of extension of the channel. For radial sealing, the sealing element can, for example, be arranged on the channel wall so that a closure is sealed in the radial direction. For axial sealing, the sealing element can, for example, be arranged around the opening of the housing, for instance, on an end face of a housing stub that surrounds the channel. The sealing element can also be designed, in particular, for both radial and axial sealing, for example, by extending from the channel wall out of the channel to the end face of a housing stub that surrounds the channel.

[0019] According to the invention, the sealing element is made of a different material than the housing. In particular, a softer material, especially one with a lower Shore hardness, can be used for the sealing element than for the housing. In this way, a harder material can be used for the housing to achieve the desired mechanical properties, while a softer material can be used for the sealing element to achieve a reliable seal.

[0020] Shore hardness refers to the Shore hardness measured according to DIN 53505.

[0021] The sealing element may preferably have one or more, in particular annular, sealing lips that surround the channel and / or the opening.

[0022] The following describes various embodiments of the contact element and the method for its manufacture, with each embodiment applying independently to both the contact element and the method. Furthermore, the individual embodiments can also be combined with one another.

[0023] In a first embodiment, the housing has a first channel extending from a first opening of the housing to the exposed part of the contact part, and a second channel extending from a second opening of the housing to the exposed part of the contact part. In a corresponding embodiment of the method, the overmolding with the housing is carried out such that a first channel is formed extending from a first opening of the housing to the exposed part of the contact part, and a second channel is formed extending from a second opening of the housing to the exposed part of the contact part.

[0024] This allows access to the contact part from both sides, enabling its connection to a terminal part of an electrical system. Specifically, a terminal part with a threaded bolt or threaded bore can be inserted through one channel, and a corresponding nut or screw through the other channel.

[0025] The sealing element is preferably intended for sealing the channel, which is closed with a cover after the fastening has been made. Additionally or alternatively, the sealing element can also be used to seal the channel through which the contact part makes contact with a connection part, in particular to seal a connection part of an electrical system, such as a base, that is inserted into the channel.

[0026] In another embodiment, the housing and the sealing element are manufactured using multi-component injection molding. In a corresponding embodiment of the process, multi-component injection molding is performed, wherein the housing is manufactured in a first injection molding step and the sealing element is manufactured in a second injection molding step. Multi-component injection molding enables particularly economical production of the contact element using different materials. For the first injection molding step, the provided electrical conductor with its attached cable lug is arranged in a first injection mold and overmolded with a first material to produce the housing. In the second injection molding step, the overmolded conductor with cable lug is preferably arranged in a second injection mold, and the sealing element(s) are overmolded onto the housing.Multi-component injection molding can be carried out particularly on an injection molding machine with multiple plasticizing units.

[0027] In another embodiment, the conductor insulation consists of a thermoplastic elastomer, in particular a thermoplastic polyurethane, and the housing consists of a thermoplastic elastomer, in particular a thermoplastic polyurethane. In this way, the materials used for the conductor insulation and the housing are so well matched that when the electrical conductor encased in the insulation is overmolded with the housing, a watertight seal is created between the housing and the insulation of the electrical conductor. In this way, individual conductor sealing can be dispensed with.

[0028] For the housing, a thermoplastic elastomer, in particular thermoplastic polyurethane, is preferably used, which has a higher Shore hardness than the conductor insulation material. Conductor insulation made of thermoplastic elastomer typically has a relatively low Shore hardness, for example Shore A 80, to allow for flexible routing of the conductor. Therefore, for the production of a dimensionally stable housing, a thermoplastic elastomer, in particular thermoplastic polyurethane, with a higher Shore hardness, for example Shore D 60 or more, is preferably used.

[0029] According to the invention, the contact element comprises a cover with which the opening can be closed. The cover is preferably captive and connected to the housing by a retaining element, for example, a thread-like retaining element. The sealing element and the cover are adapted to each other in such a way that the sealing element and the cover seal the opening. If the contact element has a first channel with a first opening and a second channel with a second opening, the contact element particularly comprises a cover with which the first opening can be closed. The second opening can be closed during installation of the contact element by a connecting element of an electrical system to which the contact element is connected.

[0030] According to the invention, the cover is at least partially made of a different material than the housing, specifically a material with a higher Shore hardness than the housing. This allows the sealing of the channel to be further improved through the interaction of the cover with the sealing element. This is advantageous because a thermoplastic elastomer, in particular a thermoplastic polyurethane, is used for the housing, as even polyurethanes with high Shore hardness are not necessarily hard enough to produce a reliably sealing cover. Polyamide, for example, has proven to be a suitable material for the cover.

[0031] The lid, made of a different material than the housing, is preferably captive and attached to the housing. For this purpose, a retaining element may be provided, for example a thread-like retaining element, to which the lid is connected, for example by a positive-locking connection.

[0032] In another embodiment, the lid and the housing have complementary fastening means for securing the lid to the housing by force and / or form. For example, the lid can have one or more tabs, and the housing can have complementary locking lugs, so that the lid can be secured to the housing by engaging the locking lugs in the tabs. The lid and the housing can also have complementary threads to secure the lid to the housing. The complementary fastening means also prevent misalignment of the lid. Furthermore, the engagement of the fastening means provides haptic feedback, informing the user that the lid is fully and correctly closed.

[0033] Optical markers may also be provided on the lid and / or the housing to visually indicate to the user whether the lid is correctly positioned or closed.

[0034] Furthermore, the housing can be equipped with anti-interference elements, such as position-coded tabs (e.g., Poka-Yoke) that correspond to correspondingly coded recesses on the connector, thus preventing incorrect connection of the connector element to the correct terminal. For such anti-interference elements, it is advantageous to use a harder material for the housing, particularly one with a higher Shore hardness than the cable insulation, so that the anti-interference elements reliably prevent contact between the contact element and the wrong terminal, even when high assembly force is applied.

[0035] In another embodiment, the electrical conductor and the cable lug are welded together, in particular by ultrasonic welding. This allows for a space-saving connection between the conductor and the cable lug. In this embodiment, it is particularly advantageous to use a thermoplastic polyurethane for the housing. Welded joints typically cannot be perfectly dimensioned, which can lead to variations in the thickness of the overmolded housing at the weld. With wall thickness-critical plastics such as polyamide, certain wall thickness variations caused by a lack of dimensional accuracy in the weld can lead to leaks. In contrast, thermoplastic polyurethanes are less sensitive to variations in wall thickness and material build-up, so that even with process-related variations in the position of the weld, a tight housing is ensured.

[0036] In another embodiment, the cable lug is crimped to the electrical conductor, preferably only in the uninsulated part of the conductor. While normal crimp connections typically also include an insulation crimp, where crimping in the insulated area of ​​the conductor is performed to stabilize the cable lug on the conductor, in this case, re-crimping the insulation is unnecessary because the overmolding with the housing provides sufficient stabilization of the crimped connection between the cable lug and the conductor. This allows for a more compact and flatter crimp design, as well as improved overmolding due to the better flow properties of the plastic resulting from the reduced flow resistance caused by the absence of insulation crimping.

[0037] In another embodiment, the contact part of the cable lug has one or more recesses through which the housing and / or the sealing element are injection-molded. Providing such recesses in the contact part results in a stronger anchoring of the contact part in the housing or the sealing element, so that the contact part does not detach from the overmolded housing even under significant mechanical stress, for example, during connection of the contact part to a terminal part. The recesses are preferably closed in the circumferential direction and can, for example, be designed as round, oval, or elongated holes.

[0038] In a corresponding embodiment of the method, the contact part of the cable lug has one or more recesses that are filled with the housing material during injection molding and / or with the sealing element material during injection molding of the housing. In this way, the contact part is reliably and positively anchored in the housing.

[0039] In another embodiment, the sealing element, which is injection-molded onto the housing, extends from the first channel through a recess in the contact part to the second channel. In a corresponding embodiment of the method, the contact part of the cable lug has one or more recesses that remain free during the injection molding of the housing and are filled with the sealing element material during the injection molding of the sealing element. The sealing element extends, in particular, from the first channel through the recess in the contact part to the second channel. This simplifies the injection molding process because a sealing element can be injection-molded onto the housing from one side of the contact part, for example, into the first channel, and this sealing element also extends to the other side of the contact part, for example, into the second channel, since the plastic can flow through the recess in the contact part to the other side during injection molding.

[0040] Further features and advantages of the contact element and the method will become apparent from the following description of exemplary embodiments, with reference to the attached drawing.

[0041] The drawing shows Fig. 1a-bein Exemplary embodiment of the contact element, Fig. 2a-b the contact element made of Fig. 1a-b after manufacturing an electrical contact with a connection part of an electrical system, Fig. 3a-leg exemplary embodiment of the method for manufacturing the contact element from Fig. 1a-b and Fig. 4a-d Cable lugs for various embodiments of the contact element.

[0042] The Figuren 1a-b show an embodiment of the contact element in isometric view ( Fig. 1a ) and section view ( Fig. 1b ).

[0043] The contact element 2 comprises an electrical conductor 4, which is sheathed with a conductor insulation 6 made of relatively soft polyurethane with a Shore A hardness of 80. One end 8 of the conductor 4 is stripped and joined by ultrasonic welding (in Fig. 1b (illustrated schematically by two black bars) is connected in an electrically conductive manner to a connection area 9 of a cable lug 10. The cable lug 10 has a flat, annular contact part 11 with a central bore 12 and several smaller recesses 13 arranged around it.

[0044] The cable lug 10 and an adjoining section 14 of the electrical conductor 4 is overmolded with an electrically insulating housing 16 made of polyurethane, with a part 17 of the contact part 11 with the bore 12 exposed.

[0045] The housing 16 forms a first nozzle 18 with a first channel 20, which runs from a first opening 22 of the housing to the exposed part 17 of the contact part 11, and a second nozzle 24 with a second channel 26, which runs from a second opening 28 of the housing 16 to the exposed part 17 of the contact part 11.

[0046] In the first and second channels 20, 26, a sealing element 30 with ring-shaped sealing lips 31 is injection-molded onto the housing 16, which is made of a softer plastic than the housing 16, for example thermoplastic polyethylene.

[0047] A captive cover 34 is connected to the housing 16 by a thread-like retaining element 32. The cover 34 is made of a harder material than the housing, for example polyamide, and is snapped into place at the end of the thread-like retaining element 32 by a positive locking connection.

[0048] The shape of the lid 34 is adapted to the shape of the first nozzle 18, so that the lid 34 can be placed on the first nozzle 18 to close the opening 22.

[0049] The Fig. 2a-b show contact element 2 from Fig. 1a after connecting to a connection part 40 of an electrical system 42 of a motor vehicle, in isometric view ( Fig. 2a ) and in section view ( Fig. 2b The connecting part 40 has a slightly conical and electrically insulating base 44 with an electrically conductive threaded bolt 46 made of metal. During connection, the contact element 2 with the second channel 26 is placed over the base 44, so that the threaded bolt 46 is guided through the bore 12 of the contact part 11 of the cable lug 10. The threaded bolt can be secured with a nut 48 through the first channel 20.

[0050] The sealing element 30 presses against the outside of the base 44 in the second channel with its sealing lips 31, thereby sealing the contact element 2 from the side of the second opening 28. Sealing from the side of the first opening 22 is achieved by placing the cover 34 onto the first nozzle 18, whereby the sealing element 30 presses against the outside of an inner contour 50 of the cover 34 with its sealing lips 31, thereby creating a watertight seal.

[0051] To securely fix the cover 34 to the housing 16, the cover 34 and the housing 16 have complementary fastening means in the form of locking lugs 52 on the first nozzle 18 and tabs 54 on the cover 34, wherein the locking lugs 52 can be engaged in the tabs 54 by rotating the fitted cover 34. As further complementary fastening means, a locking element 56 is provided on the cover 34 and a corresponding undercut 58 on the housing 16, which engage one after the other when the cover 34 is rotated and prevent the cover 34 from accidentally falling off the housing 16.

[0052] The contact element 2 enables a secure and tight connection of the electrical conductor 4 with the terminal 40 of the electrical system 42. In particular, the overmolded housing made of thermoplastic polyurethane ensures a tight connection with the conductor insulation 6. The material of the sealing element 30, which is softer than that of the housing 16, provides a good seal for the exposed part 17 of the contact part 11 from both sides, especially in combination with the harder material of the cover 34 and the base 44. The material of the housing 16, on the other hand, is hard enough to ensure a dimensionally stable housing and, in particular, to ensure the positive locking of the cover 34 to the housing 16 by means of the locking lugs 52 and the undercut 56.

[0053] It was found that contact part 2 exhibits a high degree of sealing (e.g., against water and steam jets). The assembly consisting of contact part 2 and the associated connecting part 40 can even be submerged without any water ingress. Therefore, contact part 2 is particularly suitable for applications in motor vehicles, where it may be exposed to moisture and splashing water.

[0054] The contact part connected to the connecting part 40, through the design of the sealing element, can even achieve a seal that allows immersion. A contact part connected to a connecting part even allows this assembly to be immersed.

[0055] The Figuren 3a-b illustrate an embodiment of the method for manufacturing the contact element 2 from Figur 1a in schematic sectional view.

[0056] In a first step of the process, the conductor 4, sheathed with the conductor insulation 6 and connected to the cable lug 10 by ultrasonic welding, is provided and as in Fig. 3a shown arranged in a first injection mold 80. In the injection mold 80, a first injection molding step then takes place in which the cable lug 10 and the adjoining section 14 of the electrical conductor 4 are overmolded with the housing 16 made of thermoplastic polyurethane, such that the part 17 of the contact part 11 with the bore 12 of the cable lug 10 is exposed, the first and second bases 18, 24 with the channels 20, 26 are produced and one or more of the recesses 13 remain free.

[0057] The component 82 produced in this way is then processed as described in Fig. 3b shown arranged in a second injection mold 84, in which a second injection molding step then takes place, in which the sealing element 30 is injected onto the housing 16.

[0058] The previously unused recesses 13 allow the material injected in the second injection molding step to reach both sides of the contact part 11 without requiring injection on both sides. This simplifies the manufacturing process.

[0059] After the second injection molding step, the process is completed by... Fig. 1a The separately manufactured cover 34 is connected to the holding element 32 in the contact element shown.

[0060] The Figuren 4a-d show cable lugs for various embodiments of the contact element in isometric view.

[0061] Fig. 4a shows the cable lug 10 of the contact element 2 from Fig. 1a The cable lug has a flat connection area 9 in which the conductor 4 is welded, as well as a flat contact part 11 with the central bore 12 for the threaded bolt 46 and the recesses 13 arranged around it for injection molding the sealing element 30. During the manufacture of the contact element 2, some of the recesses 13 can also be injection molded with the material of the housing 16 in the first injection molding step and thus filled with the material of the housing 16. In this way, better anchoring of the contact part 11 in the housing 16 can be achieved. Furthermore, some of the recesses can be, as in connection with Fig. 3a-b described as remaining free in the first injection molding step and being injected with the material of the sealing element 30 in the second injection molding step, which simplifies the production of the contact element 2.

[0062] Fig. 4b shows an alternative cable lug 10', which differs from cable lug 10 only by a different shape of the recesses 13', which are in Fig. 4b are elongated, while the recesses are round 13'.

[0063] Fig. 4c Figure 1 shows another alternative cable lug 10", which differs from cable lug 10 only by a contact layer 90 applied to the connecting part 9", which improves the weld connection to the conductor 4. The contact layer 90 can be applied, for example, by friction coating.

[0064] Fig. 4d Figure 1 shows another alternative cable lug 10‴, which differs from cable lug 10 only in that the connection area 9‴ is designed for a crimp connection. For this purpose, lateral crimp wings 92 are provided in the connection area 9‴, which are crimped around the strands of the conductor 4.

[0065] The cable lug 10‴ is crimped to the electrical conductor 4 only in the stripped portion. The insulation crimp normally required for crimp connections is not necessary for a contact element manufactured with the cable lug 10‴, as the overmolded housing provides sufficient stabilization of the crimp.

Claims

1. Contact element (2) for establishing electrical contact of an electrical conductor (4) to a terminal part (40) of an electrical system (42) of a motor vehicle, - having an electrical conductor (4), which is sheathed with a conductor insulation (6), and - having a cable lug (10, 10', 10", 10‴) being conductively connected to the electrical conductor (4), the cable lug having a contact part (11), - wherein the cable lug (10, 10', 10", 10‴) and an adjoining section (14) of the electrical conductor (4) are overmoulded with an electrically insulating housing (16) in such a way that a part (17) of the contact part (11) is exposed, - wherein the housing (16) comprises a channel (20, 26) which extends from an opening (22, 28) of the housing (16) to the exposed part (17) of the contact part (11), - wherein the contact element (2) comprises a cover (34) with which the opening (22, 28) can be closed, and - wherein the housing (16) consists of a thermoplastic elastomer, characterised - in that the cover (34) is formed at least partially from a harder material than the housing, and - in that a sealing element (30) for sealing the cover (34) usable for closing the opening (22, 28) is moulded onto the housing (16), wherein the sealing element (30) consists of a different material than the housing (16) and wherein the sealing element (30) and the cover (34) are adapted to one another in such a way that the sealing element (30) and the cover (34) seal the opening (22, 28).

2. Contact element according to claim 1, characterised - in that the housing (16) has a first channel (20) which extends from a first opening (22) of the housing (16) to the exposed part (17) of the contact part (11), and has a second channel (26) which extends from a second opening (28) of the housing to the exposed part (17) of the contact part (11), and - in that a sealing element (30) is moulded onto the housing (16) at the first and / or second channel (20, 26).

3. Contact element according to claim 1 or 2, characterised in that the conductor insulation (6) consists of a thermoplastic elastomer, in particular thermoplastic polyurethane.

4. Contact element according to any one of claims 1 to 3, characterised in that the cover (34) is connected to the housing (16) by a holding element (32) so as to be undetachable.

5. Contact element according to any one of claims 1 to 4, characterised in that the cover (34) and the housing (16) have complementary securing means (52, 54; 56, 58) for force-locking and / or form-locking fixing of the cover (34) to the housing (16).

6. Contact element according to any one of claims 1 to 5, characterised in that the electrical conductor (4) and the cable lug (10, 10', 10", 10‴) are welded to one another, in particular ultrasonically welded.

7. Contact element according to any one of claims 1 to 6, characterised in that the cable lug (10, 10', 10", 10‴) is crimped with the electrical conductor (4), preferably only in the non-insulated part of the electrical conductor (4).

8. Contact element according to any one of claims 1 to 7, characterised in that the contact part (11) of the cable lug (10, 10', 10", 10‴) has one or a plurality of openings (13) through which the housing (16) and / or the sealing element (30) are injected.

9. Contact element according to any one of claims 2 to 8, characterised in that a sealing element (30) moulded onto the housing (16) extends from the first channel (20) through an opening (13) of the contact part (11) to the second channel (26).

10. Method of producing a contact element (2) according to any one of claims 1 to 9, - in which an electrical conductor (4), which is sheathed with a conductor insulation (6), and a cable lug (10, 10', 10", 10‴) being conductively connected to the electrical conductor (4), the cable lug having a contact part (11), are provided, - in which the cable lug (10, 10', 10", 10"') and an adjoining section (14) of the electrical conductor (4) are overmoulded with an electrically insulating housing (16) made of a thermoplastic elastomer in such a way that a part (17) of the contact part (11) is exposed, the overmoulding being carried out in such a way that a channel (20, 26) is formed which extends from an opening (22, 28) of the housing (16) to the exposed part (17) of the contact part (17), - in which a cover (34) is provided with which the opening (22, 28) can be closed and which cover is formed at least partially from a harder material than the housing (16), and - in which a sealing element (30) made of a material different to the housing (16) is moulded onto the housing (16) to seal the cover (34) which can be used to close the opening (22, 28).

11. Method according to claim 10, characterised in that a multi-component injection moulding is carried out, wherein the housing (16) is produced in a first injection moulding step and the sealing element (30) is produced in a second injection moulding step.

12. Method according to claim 10 or 11, characterised in that the contact part (11) of the cable lug (10, 10', 10", 10‴) has one or a plurality of openings (13) which are filled with the material of the housing (16) during injection moulding of the housing (16).

13. Method according to one of claims 10 to 12, characterised in that the contact part (11) of the cable lug (10, 10', 10", 10‴) has one or a plurality of openings (13) which remain open during injection moulding of the housing (16) and are filled with the material of the sealing element (30) during injection moulding of the sealing element (30).