Methods for connecting and sealing electrical components

Abstract

Method for connecting and sealing an electrical component (30) overmolded with a non-conductive material with at least one conductor (10) comprising at least the following steps • Providing at least one line (10) with an end stripped in a connection area (12) and the component (30) to be connected thereto, • Slide a sealing sleeve (20) onto each of the at least one pipe (10), • Positioning the respective sealing sleeve (20) outside the connection area (12) plus at least one overlap area (14) of the overmolding (40) with insulation of the at least one line (10), • Connecting the component (30) to the at least one line (10) in the connection area (12), • Overmolding of the component (30), the connection area (12) and the respective overlap area to be realized (14) with the non-conductive material, • Producing each compression seal by positioning the respective sealing sleeve (20) in the overlap area (14), • Forming the compression seal by applying a force and heating at least the sealing sleeve (20).

Description

[0001] The invention relates to a method for connecting and sealing electrical components that are overmolded with a non-conductive material, with at least one line, and to an electrical component that is connected, overmolded and sealed with at least one line.

[0002] Electrical components, especially those used for power distribution in high-voltage vehicle electrical systems, are becoming increasingly smaller. Various solutions have been developed in the past to seal these electrical components against moisture and aggressive media in a vehicle. These primarily involved enclosing the components in a separate housing. For further sealing, seals were installed at the cable ends. However, this process is time-consuming and requires many individual steps. Furthermore, the applied seals can become loose or wear out quickly due to the conditions in vehicles, where vibrations and lateral forces, as well as aggressive media such as water, brake fluid, fuel, salts, and the like, are present.

[0003] In various further developments, the electrical components arranged in a housing were filled with non-conductive but sealing encapsulants. However, this requires additional equipment for the production of the encapsulated components, and here, too, the formation of the operational component requires numerous individual steps.

[0004] A recent development in the state of the art proposes the overmolding of components. In this process, the electrical component is placed in an injection mold, for example, and then overmolded with a non-conductive material that also acts as a seal. However, if an electrical component that is already connected to electrical wires is to be encased using this process, the problem arises that the electrical wires, particularly those for high-voltage electrical systems, are usually insulated with silicone sheaths, and the overmolding is carried out with a polyamide, for example, which does not adhere to the silicone or cannot be sealed against the silicone.

[0005] DE 10 2017 222 101 B3 discloses a cable connector and a method for assembling an overmolded cable connector. The cables to be connected are surrounded by a sealing element in one end region. A prefabricated sleeve applies a radial contact force to the sealing element. The end regions are then encased in a common casting compound in which the sleeves are embedded.

[0006] EP 3 340 392 A1 discloses an arrangement for the electrically conductive connection of at least two electrical lines, wherein the connection point is formed by an insulating body produced by injection molding. Sealing elements are pushed onto the resulting overlapping areas between the lines and the insulating body.

[0007] The invention is based on the object of proposing a method for isolating and effectively sealing an electrical component that is connected to at least one line.

[0008] The object of the invention is achieved by a method according to claim 1. Further preferred embodiments of the invention result from the remaining features mentioned in the subclaims.

[0009] In a method according to the invention for connecting and sealing an electrical component overmolded with a non-conductive material, which is to be connected to at least one line, at least the following steps are carried out: • Providing at least one cable with an end stripped in a connection area and the component to be connected thereto, • Pushing a sealing sleeve onto at least one line, • Positioning the respective sealing sleeve outside the connection area plus at least one overlap area of ​​the overmolding to be realized with an insulation of the at least one line, • Connecting the component to the at least one line in the connection area, • Overmolding of the component, the connection area and the respective overlap area to be realized with the non-conductive material, • Create a press seal by positioning the respective sealing sleeve in the overlap area • Forming the press seal by applying a force and heating at least the sealing sleeve.

[0010] An electrical component, as defined by the invention, is a component or assembly into which electrical current is fed and / or discharged. In particular, the electrical component can be a distributor for electrical energy or current, or a consumer, such as a lighting device powered by electrical current. In the following, the term "component" is also used synonymously with "electrical component."

[0011] Most preferably, the electrical component is a distributor for electrical energy in a high-voltage electrical system in a vehicle. Such a distributor can preferably be implemented in the form of a so-called busbar. This is commonly understood to mean an arrangement of conductors that act as a central distributor of electrical energy, since the busbar is connected to all incoming and outgoing lines. Busbars are usually uninsulated. According to the invention, the insulation takes place in one of the subsequent steps of the disclosed method.

[0012] An on-board electrical system comprises all of the electrical components in a vehicle and serves to supply power and facilitate the flow of information between the vehicle's components and control units. A high-voltage on-board electrical system describes an on-board electrical system that operates with alternating voltages above 30 V up to 1 kV or with direct voltages above 60 V up to 1.5 kV.

[0013] In the method according to the invention, the electrical component is to be connected to at least one wire. A wire is understood to be an electrical line, i.e., a means for transmitting electrical current and information. A wire can be formed with one or more individual conductors, also referred to as stranded wires, and is usually insulated from the outside. Various plastics, including silicones, are typically used as insulating materials to surround the conductors and insulate them from one another.

[0014] To implement the method according to the invention, the at least one wire to be connected to the electrical component must be stripped in an area where the connection is to be made. The insulating layer must therefore be removed there. This area is usually one of the ends of the respective wire. The stripped area will be referred to below as the connection area within the context of the method.

[0015] The at least one cable with the stripped end is now prepared for the subsequent steps, as is the electrical component to which the at least one cable is to be connected. A sealing sleeve is pushed onto each of the at least one cables. A sealing sleeve is a substantially cylindrical body with a bore or passage along a longitudinal axis that passes through the center of the substantially circular base of the cylindrical body. Of course, any other shapes can also be selected for the sealing sleeve, provided the bore or passage is formed therein.

[0016] The inner diameter of the sealing sleeve must be matched to the cable to be connected and the planned dimensions of the overmolding of the electrical component, which will follow in a later step. It should be selected so that the sealing sleeve can be easily slid onto the respective cable, but also so that a compression seal can be created later, as will be explained below.

[0017] The sealing sleeve must be positioned outside the connection area. Furthermore, the method according to the invention is intended to create an overlap area between the overmolding of the electrical component and the insulation of the at least one electrical line. In this area, the overmolding should therefore cover the insulation of the at least one line, at least in sections. Therefore, the sealing sleeve must also be positioned far enough away from the electrical component on the line to form this overlap area. Therefore, the sealing sleeve must be positioned away from the electrical component by at least the amount of the connection area plus the overlap area.

[0018] The component is then connected to the at least one cable in its connection area. This connection can be force-fitting, material-fitting, and / or form-fitting, as will be explained in more detail elsewhere.

[0019] Once all the necessary wires are connected to the electrical component, it is overmolded with a non-conductive material. This means that the electrical component is encased in a material that does not conduct electrical current and thus acts as insulation for the electrical component. This encapsulation or overmold is created using an injection molding process, preferably an injection molding process.

[0020] In an injection molding process, the component with at least one connected wire is placed into an injection mold, which is filled with a non-conductive material. The injection mold determines the thickness of the encapsulation. The overmolding or encapsulation should cover not only the electrical component but also the connection area of ​​the at least one wire and the overlap area of ​​the at least one wire.

[0021] Once the overmolding has been completed and cured, a compression seal is formed in the overlap area using the sealing sleeve by sliding the sealing sleeve into the overlap area. A compression seal is achieved when the inner diameter of the sealing sleeve is at least slightly smaller than the outer diameter of the at least one cable plus the overmolding in the overlap area. By sliding the sealing sleeve into the overlap area, the insulation and the non-conductive material of the overmolding are pressed together by the sealing sleeve, creating a seal against each other in the overlap area.

[0022] The previously performed steps, with the exception of the overmolding of the electrical component and the at least one connected lead, are performed for each of the leads connected to the component. These steps can be performed individually for each lead, or each step can be performed for each lead to be connected, followed by the next step.

[0023] With the method according to the invention, an electrical component is connected to at least one cable, completely surrounded by an insulating material up to an overlapping area of ​​the at least one cable, and sealed and protected against the ingress of water, fuel, brake fluid, and other aggressive media by a compression seal using the sealing sleeve. The method is simple to implement without requiring significant additional effort.

[0024] According to the invention, it is further provided that the press seal is formed by applying a force and heating at least the sealing sleeve. Since the inner diameter of the sealing sleeve is at least slightly smaller than the outer diameter of the overlap region of the at least one overmolded line, displacement into the overlap region can be facilitated by applying a force to the sealing sleeve. The sealing sleeve can be pressed with pressure in the direction of the overlap region and into the desired target position, or it can be moved into the overlap region by applying a tensile force. Alternatively or additionally, the sealing sleeve can be heated so that it expands and can thus be moved more easily into the desired position in the overlap region.The temperature for heating the sealing sleeve should be selected so that neither the sealing sleeve itself nor the non-conductive material of the overmolding is adversely affected by the increased temperature.

[0025] The connection of the at least one cable to the electrical component should be frictionally, materially, and / or positively connected. In a preferred embodiment, the connection of the at least one cable to the electrical component is achieved by ultrasonic welding or laser welding.

[0026] Ultrasonic welding belongs to the group of friction welding processes. The components to be joined are joined using high-frequency mechanical vibration, which leads to heating between the components due to molecular and interfacial friction.

[0027] Laser beam welding, also known as laser welding, uses a laser beam. It is particularly suitable for welding components that require high welding speeds, a narrow and slender weld seam, and minimal thermal distortion.

[0028] Alternatively, the connection of the at least one cable to the electrical component can also be implemented as a plug connection.

[0029] In a further preferred embodiment, the overmolding is carried out with a thermoplastic, in particular with polyamide 12. Thermoplastics are plastics that can be deformed within a specific temperature range. This is a reversible process, provided the material is not overheated, which causes what is known as thermal decomposition. Furthermore, thermoplastics are weldable. The use of polyamides is further preferred, as they exhibit very good strength and toughness, as well as processability and chemical resistance.

[0030] Polyamide 12, for example, can be used as a non-conductive material for overmolding the component and the at least one connected cable. Polyamide 12, also abbreviated as PA12, is a semi-crystalline thermoplastic with the lowest water absorption of all polyamides. It is characterized by high toughness and good chemical resistance, as well as heat distortion temperature up to 50 °C. Its properties make it particularly suitable for use in humid environments or when high dimensional accuracy is required.

[0031] In a next preferred embodiment, the sealing sleeve is made of a plastic or a ceramic material. Plastic is suitable due to its chemical resistance, flexible shapeability, and lightweight properties. Ceramic sealing sleeves are made of or with so-called technical ceramics and are advantageous due to their high hardness, chemical resistance, wear resistance, and corrosion resistance.

[0032] Both the sealing sleeve and the overmolding can be fiber reinforced. Fibers are added to the base material of the sealing sleeve or the non-conductive material of the overmolding to create a composite material with improved properties. Among other things, the fibers increase the strength of the surrounding material. The fibers can be glass fibers, for example, depending on the specific application. However, ceramic fibers, carbon fibers, or nylon fibers can also be used. In any case, the properties of the fibers should be matched to the properties of the surrounding material.

[0033] In yet another preferred embodiment of the method according to the invention, the sealing sleeve is positioned such that it encloses the line-side end of the overlap region. The line-side end of the overlap region is the region of the at least one line in which the overlap of the non-conductive material with the insulation of the at least one line ends. In particular, this refers to the terminating edge of the overmolding. In this embodiment of the method, it is provided that precisely that edge, or the line-side end of the overlap region, is enclosed by the sealing sleeve. The sealing sleeve should therefore be positioned such that it covers the line-side end of the overlap region, i.e., the line-side end of the overlap region is concealed by the sealing sleeve.The sealing sleeve thus provides additional protection for the edge area of ​​the line-side end of the overmold in the overlap area against the penetration of aggressive media and also against mechanical damage.

[0034] Another preferred embodiment provides that the press seal is and / or is formed with at least one locking point. In the sense of the invention, this should mean that a positive connection is realized between the sealing sleeve and the overmolding by forming at least one locking point in order to secure the position of the sealing sleeve in use, in which vibrations and external forces act on the overmolding component. For this purpose, a raised portion or protuberance can be provided in the sealing sleeve, i.e. in the feedthrough or bore, and a corresponding depression or recess can be formed in the overlap area of ​​the overmolding. If the sealing sleeve is pushed into the overlap area, the raised portion and the corresponding depression engage with one another and thus form a positive connection that secures the position of the sealing sleeve.

[0035] However, it is also within the scope of the invention if the elevation or protrusion is formed in the overlap area of ​​the overmolding and the corresponding depression or recess is formed inside the sealing sleeve, i.e., along the passage or bore in the sealing sleeve. The recess can also be an opening in the sealing sleeve or a hole in the sealing sleeve.

[0036] The elevation or protrusion can be point-shaped or linear, regardless of the element on which it is formed, to form the at least one locking point. More than one locking point can be formed, and the individual elevations or protrusions can have the same or different shapes. However, the depression or recess on the counter element should largely correspond to the elevations or protrusions to ensure a secure hold.

[0037] A sealed electrical component overmolded with a non-conductive material is connected to at least one line, wherein the component is connected to an end of the at least one line that is stripped in a connection region. The component, the connection region, and an overlap region of the at least one line are overmolded with a non-conductive material, wherein an insulation of the at least one line is also overmolded in the overlap region. A compression seal is formed in each overlap region by means of a sealing sleeve. The sealing sleeve encompasses the insulation in the overlap region.

[0038] The inventive method for an overmolded electrical component allows for a simple and cost-effective, secure seal for electrical components connected to electrical lines. A very compact design can be achieved.

[0039] The various embodiments of the invention mentioned in this application can be advantageously combined with one another, unless otherwise stated in the individual case.

[0040] The invention is explained below in exemplary embodiments with reference to the accompanying drawings. They show: Fig. 1 an exemplary sequence of the method according to the invention in a schematic representation, and Fig. 2 a detail from Fig. 1.

[0041] Fig. Figure 1 shows a schematic representation of an exemplary sequence for carrying out the method according to the invention. For the sake of clarity, Fig. 1b to 1d, all components are no longer labeled separately. Reference lines indicate the alignment of the individual elements to each other and facilitate their assignment.

[0042] The method according to the invention is intended to connect an electrical component 30 to, for example, three lines 10, and to overmold the component 30 and, in some areas, the lines 10 with a non-conductive material in order to insulate the assembly. In this exemplary embodiment, the electrical component 30 is a busbar, by means of which electrical energy is distributed for a high-voltage electrical system of a vehicle.

[0043] In Fig. 1a it can be seen that three lines 10, which are stripped in a connection area 12, are provided. Fig. 1b shows that a sealing sleeve 20 has been pushed onto each of the lines 10 and - as can be seen from the overall view of the Fig. 1 - have been pushed out of the connection area 12 and the overlap area 14 to be realized. In each of these overlap areas 14, the subsequent overmolding 40, by means of which the busbar 30 is to be insulated, is to cover the insulation of the lines 10 at least in sections. The busbar 30 is in Fig. 1b is connected to each of the three lines 10 in their connection area 12 by means of ultrasonic welding.

[0044] Out of Fig. 1c shows that the overmolding 40 of the busbar 30 was made of a thermoplastic material such as polyamide 12. This was done in an intermediate step using an injection molding process. Fibers may also have been embedded in the plastic to reinforce the overmolding 40. During the overmolding process, the overlap area 14 on each of the lines 10 was also created, in which the polyamide 12 also encloses the line 10.

[0045] The sealing sleeves 20 are then pushed into the overlap area 14 under the influence of a compressive force in the direction indicated by the arrows. The sealing sleeves 20 are made of a plastic material, making them resistant to the aggressive media found in a vehicle's engine compartment. The sealing sleeves 20 are now positioned such that the respective line-side end of the overmolding 40, i.e., the edge formed in this process, is enclosed and concealed by the sealing sleeve 20.

[0046] Fig. 2a takes effect Fig. 1c and marks with a circle a detail which is in Fig. 2b is shown enlarged. Fig.2b illustrates that in the overlapping area 14 two locking points 42 are formed in the form of an elevation, to which two corresponding recesses 22 are provided in the sealing sleeve 20, so that when the sealing sleeve 20 is pushed on, a positive connection is achieved between the respective sealing sleeve 20 and the overmolding 40, which secures the position of the sealing sleeve 20 even under the vehicle-specific influences.

[0047] Since the inner diameter of the sealing sleeves 20 is smaller than the outer diameter of the overmolding 40 in the overlapping areas 14, a press seal is created by sliding on the sealing sleeves 20, i.e. a pressure between the sealing sleeve 20, the overmolding 40 in the overlapping area 14 and the insulation of the line 10, which seals the connection.

[0048] The result is an assembly in which the busbar 30 is connected to three lines 10 and sealed against the ingress of water, fuel, brake fluid, or other media. The assembly can be designed to be very compact and small by applying the method according to the invention. List of reference symbols 10 Line 12 Connection area of ​​the cable 14 Overlap area 20 sealing sleeve 22 Recess for the locking point 30 electrical components 40 Overmolding 42 rest point

Claims

[1] Method for connecting and sealing an electrical component (30) overmolded with a non-conductive material with at least one line (10) with at least the following steps • Providing the at least one cable (10) with an end stripped in a connection area (12) and the component (30) to be connected thereto, • Pushing a sealing sleeve (20) onto the at least one line (10), • Positioning the respective sealing sleeve (20) outside the connection area (12) plus at least one overlap area (14) of the overmolding (40) to be realized with an insulation of the at least one line (10), • Connecting the component (30) to the at least one line (10) in the connection area (12), • Overmolding the component (30), the connecting region (12) and the respective overlap region (14) to be realized with the non-conductive material, • Producing a press seal by positioning the respective sealing sleeve (20) in the overlap area (14), • Forming the press seal by applying a force and heating at least the sealing sleeve (20). [2] Method according to claim 1, characterized by that the at least one line (10) is connected to the component (30) by means of ultrasonic welding or laser beam welding. [3] Method according to one of the preceding claims, characterized by that the overmolding is done with a thermoplastic material. [4] Method according to one of the preceding claims, characterized by that the sealing sleeve (20) is formed with a plastic or a ceramic material. [5] Method according to one of the preceding claims, characterized bythat the overmolding (40) is formed with a fiber reinforcement and / or the sealing sleeve (20) is formed with a fiber reinforcement. [6] Method according to one of the preceding claims, characterized by that the sealing sleeve (20) is positioned so that it encloses the line-side end of the overlap area (14). [7] Method according to one of the preceding claims, characterized by that the press seal is and / or is formed with at least one locking point (42). [8] Method according to one of the preceding claims, characterized by that the component (30) is a distributor for electrical energy in a high-voltage electrical system of a vehicle and / or a consumer.

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