electrical connection

Abstract

The present invention relates to an electrical connection (10) comprising a bushing (12) having a geometric central axis (14), an electrical conductor (16) passing through the bushing (12) along the geometric central axis (14), and an insulating layer (18) electrically insulating the bushing (18) from the conductor (16). It is proposed that the bushing (12), the insulating layer (18), and the electrical conductor (16) are preferably compressed together during a rotary forging process to achieve mechanical cold transformation.

Description

Technology Field

[0001] The present invention relates to an electrical connection part, and the electrical connection part is,

[0002] Bushing having a geometric central axis,

[0003] An electrical conductor passing through the bushing along the geometric central axis, and

[0004] It includes an insulating layer that electrically insulates the bushing from the conductor. Background Technology

[0005] An electrical connection (or electrical connector arrangement) is installed in the jacket or casing of an internal combustion engine's exhaust system and can be electrically connected to an electrical component to be placed in the jacket. The electrical component is preferably an electrically heatable grid or honeycomb body of a catalytic converter intended to be supplied with current through an electrical conductor after the electrical component is installed. The electrical connection is inserted into a mounting flange or an opening in the jacket, and a bushing is secured to the opening, for example, by welding it to the jacket. The end of the electrical conductor opposite the electrical component can be connected to an electrical cable. The end of the cable opposite the electrical connection can be connected to a power source, for example, a battery or a control unit of the vehicle.

[0006] The types of electrical connections mentioned above are well known in the art. For example, EP 2 828 932 B1 describes an electrical connection capable of drawing currents ranging from 30 amperes to several hundred amperes. The insulating layer is formed of compressed ceramic powder and is virtually incompressible. The outer cross-section of the electrical connection has a non-circular shape, such as a polygonal cross-section, to avoid rotation of the inner electrical connection, such as a jacket, even under very high torques.

[0007] US 6,025,578 describes an electrical connection having a sacrificial electrode, a protective layer, or other types of protective components in contact with the bushing on the outside of a jacket, etc., where the bushing is welded. The bushing is made of metal, and the insulating layer is made of aluminum oxide. The sacrificial electrode is a zinc block. This prevents corrosion of the bushing or the electrical conductor by corroding the sacrificial electrode when an electrolyte, such as brine, accumulates on the bushing.

[0008] EP 0 902 991 B1 describes the type of electrical connection mentioned above. Other types of connections are proposed between the end of an electrical conductor opposite an electrical component (e.g., an electrically heatable grid or honeycomb body of a catalytic converter) and an electrical cable. Thus, a reliable electrical connection can be achieved in a fast and easy manner.

[0009] Known electrical connections have several disadvantages:

[0010] - An insulating layer made of ceramic material has the disadvantage that when the bushing is welded to the jacket or casing, cracks may occur in the insulating layer due to the different thermal shrinkage values ​​of the bushing material and the ceramic material of the insulating layer, thereby affecting good insulation properties and the airtightness of the electrical connections.

[0011] - During the use of electrical connections, the temperature may fluctuate between the ambient temperature (up to 40°C) when the combustion engine and catalytic converter are turned off and cooled, and about +1,000°C when the combustion engine and catalytic converter are in operation. This may have a negative effect on the physical, mechanical, electrical, and thermal properties and the properties of the electrical connections.

[0012] - Known electrical connections can only withstand very limited amounts of force and torque. The main problem is not that the entire electrical connection loosens or that the electrical connection slips out of the mounting flange or opening of the welded jacket or casing. Rather, the mechanical interconnection between the electrical conductor and the insulation layer, and / or between the insulation layer and the bushing, may loosen or break due to large force and / or torque values ​​acting on the electrical connection. For example, electrical connections known from US 9,225,107 B2 can only absorb torques of up to 8 Nm. This amount must be increased.

[0013] - The sealing effect of the insulation layer is not satisfactory. There may be leakage of gas or fluid (e.g., exhaust gas) into the environment from inside the jacket or casing through openings in the jacket or casing or electrical connections welded to mounting flanges. Gas or fluid is chemically aggressive and can lead to corrosion of bushings and / or electrical conductors. For this reason, US 6,025,578 proposes some types of protective configurations to prevent corrosion.

[0014] Accordingly, the object of the present invention is to provide an electrical connection that overcomes at least some of the disadvantages mentioned above. In particular, the object is to provide an electrical connection having the following properties:

[0015] - The electrical connection must be able to handle a minimum voltage of up to 52 V DC without damage, preferably up to 100 V DC.

[0016] - The electrical connection must be able to handle a minimum current value of 150A, preferably up to 200A, without damage.

[0017] - Electrical connections must have temperature stability and / or significant mechanical flexibility to compensate for large temperature changes exceeding 1,000°K without damage.

[0018] - The electrical connection must provide a hermetic seal of the jacket or casing to which it is attached (e.g., welded or screwed) - having a maximum leakage of less than 30 ml / min, preferably less than 25 ml / min at a pressure of 0.3 bar of the jacket or casing.

[0019] - The electrical connection must provide good electrical insulation of the electrical conductor in relation to the bushing and jacket or casing, and in particular, the electrical connection must provide an insulation resistance of more than 10 MΩ (preferably a few GΩ) under ambient environmental conditions (e.g., a temperature of 22°C + / -2°C, a pressure of about 1,000 hPa and 35% - 70% relative humidity) and a DC voltage of 500 V.

[0020] - The electrical connection must have a breaking torque of more than 15 Nm, preferably more than 16 Nm, particularly preferably more than 17 Nm, and particularly about 20 Nm.

[0021] This objective is solved by an electrical connection comprising the features of claim 1. In particular, including the type of electrical connection identified above, it is proposed that a bushing, an insulating layer, and an electrical conductor be compressed together by mechanical cold transformation. The bushing, the insulating layer, and the electrical conductor are arranged coaxially with respect to the geometric central axis of the bushing and then compressed together by mechanical cold transformation. The bushing, the insulating layer, and the electrical conductor are preferably compressed together during a rotary forging process. Pressure is applied to the outer circumferential surface of the bushing of the electrical connection. The pressure is preferably directed radially inward toward the geometric central axis.

[0022] Due to mechanical cold transformation, the interconnection between the bushing and the insulation layer, and between the insulation layer and the electrical conductor, is significantly increased. The electrical connection can absorb much higher force and torque values ​​without damage. In particular, the mechanical interconnection between the electrical conductor and the insulation layer and / or between the insulation layer and the bushing does not loosen or break even when high force and torque values ​​are applied to the electrical connection.

[0023] The bushing, insulation layer, and electrical conductor are preferably rotationally symmetric with respect to the geometric central axis. In particular, in the cross-sectional view, the bushing, insulation layer, and electrical conductor all have a circular or circular ring shape.

[0024] The electrical conductor is dimensioned to withstand a minimum voltage of 52V DC and a current of up to 200A. To this end, the diameter of the conductor is proposed to be 5.0mm to 8.0mm, preferably 6.0mm to 7.5mm. The outer diameter of the bushing of the electrical connection is determined by the dimensions of the mounting flange or opening to which the bushing is secured and / or the intended use of the electrical connection. In particular, the bushing must fit neatly into the opening within the jacket or casing. A typical example of the outer diameter of the bushing is 12.0mm to 18.0mm, preferably about 14.0mm. In cross-section, the bushing has a thickness between the inner and outer surfaces, preferably 1.0mm to 5.0mm, preferably about 2.0mm. The thickness of the insulation layer depends on the defined diameters of the electrical conductor and the bushing, as well as the electrical properties achieved by the electrical connection. For example, the insulating layer must achieve an insulation resistance of greater than 10 MΩ (preferably up to a few GΩ) under ambient environmental conditions (e.g., a temperature of 22°C + / -2°C, a pressure of about 1,000 hPa, and a relative humidity of 35% - 70%) and a DC voltage of 500 V. To achieve these insulation characteristics, depending on the material used for the insulating layer, the insulating layer has a thickness of at least 1.2 mm, preferably about 1.6 mm.

[0025] According to a preferred embodiment of the present invention, it is proposed that an electric conductor has an outer surface having at least one of protrusions and concaves, an arithmetic mean roughness of at least Ra = 1 μm (or greater) on at least a portion of the outer surface of the electric conductor, which is covered by an insulating layer. The roughness of the outer surface may be Ra > 2 μm, preferably Ra > 3 μm, particularly preferably Ra > 4 μm, Ra > 5 μm, or even Ra > 10 μm. The roughness is configured to provide protrusions (i.e., positive peaks) and / or concaves (i.e., negative peaks or troughs) with an irregular distribution relative to the average surface extension. The desired roughness can be achieved during the manufacture of the electric conductor, i.e., by machine turning, for example, by reducing the rotational speed at which the outer surface is machined by a cutting or milling tool. In particular, when the rotational speed at which the outer surface is machined is reduced, the roughness of the outer surface may increase. Alternatively, the desired roughness value can also be achieved by an additional process step after the manufacture of the electrical conductor.

[0026] During mechanical cold transformation, pressure acts radially on the outer surface of the bushing. The bushing transmits at least a portion of the radial pressure to an insulating layer that is compressed onto the outer surface of the electrical conductor. A portion of the insulating material is compressed into recesses provided on the outer surface of the electrical conductor and / or protrusions provided on the outer surface of the electrical conductor are compressed into the insulating material. Thus, an interlocking connection is established between the electrical conductor and the insulating layer. This can additionally increase the force and torque values ​​that the electrical connection can absorb without damage. In particular, the mechanical interconnection between the electrical conductor and the insulating layer does not loosen or break even when high force and torque values ​​are applied to the electrical connection.

[0027] Preferably, the protrusions have a cross section having sidewalls extending from the base and ends of the base on the outer circumferential surface of the electrical conductor and converging toward the top of the protrusion. Similarly, the grooves may have a cross section having an opening on the outer circumferential surface and sidewalls extending from the ends of the opening and converging toward the bottom of the groove. A preferred cross section for the grooves is U-shaped so that the material of the insulating layer can more easily enter and diffuse into the groove. Of course, the grooves may also have any other cross section, e.g., a V-shaped cross section or a combination of U-shaped and V-shaped cross sections. A preferred cross section for the protrusions is V-shaped so that the protrusions more easily enter into the material of the insulating layer. Of course, the protrusions may also have any other cross section, e.g., a U-shaped cross section or a combination of U-shaped and V-shaped cross sections. The preferred depth of the recesses and the preferred height of the protrusions may each be 0.05 mm to 0.3 mm, preferably about 0.15 mm, relative to the rest of the outer circumferential surface of the electrical conductor.

[0028] Additionally, it is proposed that the protrusions and / or depressions provided on the outer surface of the electrical conductor have circumferential longitudinal extensions and / or axial longitudinal extensions. For example, the protrusions or depressions may have longitudinal extensions that are essentially circumferential, i.e., extending around the geometric central axis of the bushing. Alternatively, the protrusions or depressions may have longitudinal extensions that are essentially axial, i.e., parallel to the geometric central axis of the bushing. Furthermore, it is possible for the protrusions and / or depressions to have longitudinal extensions that extend in the circumferential direction as well as the axial direction. In that case, the protrusions and / or depressions extend in an inclined or spiral (i.e., helical) manner on the outer surface of the electrical conductor. Such protrusions and / or depressions may be achieved during the manufacture of the electrical conductor, for example, by a specific feed rate relative to the rotational speed and a specific cutting depth of a cutting or milling tool that causes the outer surface to be machined. Alternatively, the protrusions and / or depressions may also be achieved by an additional process step after the manufacture of the electrical conductor. Of course, it is also possible for the protrusions and / or grooves of the first group to have longitudinal extensions in the first direction and for the protrusions and / or grooves of the second group to have longitudinal extensions in the second direction and for the protrusions and / or grooves of the first group to intersect with the protrusions and / or grooves of the second group.

[0029] It is preferable that protrusions or depressions are part of the ribbed external circumferential surface of the electrical conductor. The ribbed surface preferably comprises a plurality of grooves. The grooves of a first group of grooves extend parallel to each other, preferably at equal distances, and the grooves of a second group of grooves extend parallel to each other, preferably at equal distances. The grooves of the first group of grooves are obliquely connected to the second group of grooves, and the angle is greater than 0° and less than 180°. Preferably, the angle between the first and second grooves is 90°, thereby creating a ribbed surface having rectangular or square shapes between the grooves. Alternatively, the angle is between 10° and 80°, thereby creating a ribbed surface having rhombuses between the grooves. Of course, instead of or additionally to the grooves, the ribbed surface may also comprise protrusions.

[0030] To facilitate the material of the insulating layer entering and diffusing into grooves and / or protrusions entering into the material of the insulating layer, it is proposed that the insulating layer be made of a material having a lower hardness than the material from which the electrical conductor is made. In particular, it is desirable that the material of the insulating layer have a hardness of less than 5.5 on the Mohs scale, preferably lower than that of magnesium oxide (MgO). Preferably, the material of the insulating layer has a Mohs scale hardness of approximately 1.5 to 4.0, particularly 2.0 to 3.0. For comparison, gold has a Mohs scale hardness of approximately 2.5 to 3.0, copper coins have a hardness of approximately 3.0, and steel has a hardness of approximately 6.0 to 6.5. The material of the electrical conductor has a greater hardness than the insulating material.

[0031] According to another preferred embodiment of the present invention, it is proposed that the bushing have an inner surface having at least one of protrusions and concaves, with an arithmetic mean roughness of at least Ra = 1 μm (or greater) on at least a portion of the inner surface of the bushing covering the insulating layer. Thus, the bushing has the form of a hollow cylinder, and the inner surface of the bushing where the insulating layer is located comprises the desired roughness, protrusions, and / or concaves. The roughness of the inner surface may be Ra > 2 μm, preferably Ra > 3 μm, particularly preferably Ra > 4 μm, Ra > 5 μm, or even Ra > 10 μm. The roughness is configured to provide protrusions (i.e., positive peaks) and / or concaves (i.e., negative peaks or troughs) with an irregular distribution relative to the average surface extension. The desired roughness can be achieved during the manufacture of the bushing, for example, by reducing the rotational speed at which the inner surface is machined by a cutting or milling tool, i.e., by mechanical turning. In particular, if the rotational speed at which the inner surface is machined is reduced, the roughness of the circumferential surface may increase. Alternatively, the desired roughness value can also be achieved by an additional process step after the manufacture of the bushing.

[0032] During mechanical cold transformation, pressure is applied radially to the outer surface of the bushing. The inner surface of the bushing is compressed radially onto the insulating layer. A portion of the insulating material is compressed into the recesses provided on the inner surface of the bushing and / or the protrusions provided on the inner surface of the bushing are compressed into the insulating material. Thus, an interlocking connection is established between the bushing and the insulating layer. This can additionally increase the force and torque values ​​that the electrical connection can absorb without damage. In particular, the mechanical interconnection between the bushing and the insulating layer does not loosen or break even when high force and torque values ​​are applied to the electrical connection.

[0033] Preferably, the protrusions have a cross section having sidewalls extending from the base and ends of the base on the inner circumferential surface of the bushing and converging toward the top of the protrusion. Similarly, the grooves may have a cross section having sidewalls extending from the ends of the opening and converging toward the bottom of the groove on the inner circumferential surface. A preferred cross section for the grooves is U-shaped so that the material of the insulating layer can more easily enter and diffuse into the groove. Of course, the grooves may also have any other cross section, e.g., a V-shaped cross section or a combination of U-shaped and V-shaped cross sections. A preferred cross section for the protrusions is V-shaped so that the protrusions more easily enter into the material of the insulating layer. Of course, the protrusions may also have any other cross section, e.g., a U-shaped cross section or a combination of U-shaped and V-shaped cross sections. The preferred depth of the recesses and the preferred height of the protrusions may each be 0.05 mm to 0.3 mm, preferably about 0.15 mm, relative to the rest of the inner circumferential surface of the bushing.

[0034] Additionally, it is proposed that the protrusions and / or recesses provided on the inner circumferential surface of the bushing have at least one of a circumferential extension and an axial extension. For example, the protrusions or recesses may essentially have a longitudinal extension extending in the circumferential direction, i.e., around the geometric central axis of the bushing. Alternatively, the protrusions or recesses may essentially have a longitudinal extension extending in the axial direction, i.e., parallel to the geometric central axis of the bushing. Furthermore, it is possible for the protrusions and / or grooves to have a longitudinal extension extending in the circumferential direction as well as the axial direction. Thus, the protrusions and / or grooves extend in an inclined or spiral (i.e., helical) manner on the inner circumferential surface of the bushing. Such protrusions and / or grooves may be achieved during the manufacture of the bushing, for example, by a specific feed rate relative to the rotational speed and a specific cutting depth of a cutting or milling tool that causes the inner circumferential surface to be machined. Alternatively, the protrusions and / or grooves may also be achieved by an additional process step after the manufacture of the bushing. Of course, it is also possible for the protrusions and / or grooves of the first group to have longitudinal extensions in the first direction and for the protrusions and / or grooves of the second group to have longitudinal extensions in the second direction and for the protrusions and / or grooves of the first group to intersect with the protrusions and / or grooves of the second group.

[0035] According to a preferred embodiment, the bushing has recesses in the form of axial grooves provided on the inner circumferential surface of the bushing and spaced apart from each other in the circumferential direction. The grooves may have longitudinal extensions that extend axially, that is, parallel to the geometric central axis of the bushing. Preferably, the grooves are spaced evenly apart from each other in the circumferential direction, that is, each is separated from neighboring grooves by a given angle. When the angle is 120°, there are three grooves spaced evenly apart from each other on the inner circumferential surface of the bushing. Of course, different numbers of grooves spaced evenly or unequally apart and different angles between the grooves may also be provided.

[0036] Preferably, the axial grooves do not extend along the entire axial extension of the inner circumferential surface of the bushing. Rather, it is proposed that the grooves extend along only a portion of the inner surface of the bushing, starting from one end surface of the bushing and ending before reaching the opposite end surface of the bushing. Thus, the grooves do not reach the opposite end surface of the bushing. This can additionally increase the force and torque values ​​that the electrical connection can absorb without damage. In particular, the electrode displacement force acting on the electrical conductor in the direction toward the opposite end surface of the bushing will prevent the electrical conductor from being pulled or compressed from the bushing along with the insulating layer. The electrode displacement force is preferably greater than 5,000 N, particularly between 5,500 N and 10,000 N.

[0037] To facilitate the material of the insulating layer entering and diffusing into the grooves and / or the protrusions entering into the material of the insulating layer, it is proposed that the insulating layer be made of a material having a lower hardness than the material from which the bushing is made. Preferably, the material of the insulating layer has a Mohs scale hardness of approximately 1.5 to 4.0, particularly 2.0 to 3.0. The material of the bushing has a greater hardness than the insulating material.

[0038] According to a preferred embodiment of the present invention, it is proposed that the bushing and / or electrical conductor be made of stainless steel, in particular a nickel-chromium-iron alloy. In principle, the bushing and / or electrical conductor may be made of any suitable material, provided that it possesses the necessary physical, mechanical, electrical, and thermal properties required for the electrical connection.

[0039] According to another preferred embodiment of the present invention, it is proposed that the insulating layer be made of a material comprising at least 50% phyllosilicate mineral. Preferably, the insulating material comprises more than 70%, particularly about 90%, of phyllosilicate mineral. The remaining material may be a laminate or bonding material. Preferably, the material of the insulating layer is less hygroscopic than magnesium oxide (MgO). In principle, any material may be used for the insulating layer as long as it possesses the necessary physical, mechanical, electrical, and thermal properties required for the insulating material in the electrical connection. In particular, the material must be sufficiently elastic to compensate for the thermal expansion of the different materials used in the electrical connection due to extensive thermal fluctuations during the intended use of the electrical connection without breakage or cracking. Thus, a high degree of and long-lasting airtightness of the electrical connection can be ensured.

[0040] Further features and advantages of the present invention are described below with reference to the accompanying drawings. It should be noted that each feature illustrated in the drawings and described below may be of particular importance to the present invention in itself, even if not explicitly illustrated in the drawings or mentioned in the description. Additionally, any combination of features illustrated in the drawings and described below may be of particular importance to the present invention, even if such combination is not explicitly illustrated in the drawings or mentioned in the description. The drawings illustrate the following. Brief explanation of the drawing

[0041] FIG. 1 illustrates an example of an electrical connection part according to a preferred embodiment of the present invention. Figure 2 shows an exploded view of the electrical connection part of Figure 1. Figure 3 shows a partial cross-sectional view of the electrical connection part of Figure 2. Figure 4 shows details A of the electric conductors in Figures 2 and 3. Figure 5 shows a partial cross-sectional view of the electrical connection part of Figure 1. Figure 6 illustrates the electrical connection of Figure 1 before mechanical cold transformation. Figure 7 illustrates the electrical connection of Figure 1 after mechanical cold transformation. FIG. 8 illustrates a cross-sectional view through protrusions provided on the outer surface of an electric conductor. FIG. 9 illustrates a cross-sectional view through grooves provided on the outer surface of an electric conductor. FIG. 10 illustrates an example of use of an electrical connection part according to the present invention. FIG. 11 illustrates an example of an electrical connection part according to another preferred embodiment of the present invention. Figure 12 shows an exploded view of the electrical connection part of Figure 11. Figure 13 shows details B of the electric conductor in Figure 12. FIG. 14 illustrates another use example of an electrical connection part according to the present invention. Figure 15 shows details C of the electrical connection part of Figure 14. FIG. 16 illustrates another example of use of an electrical connection part according to the present invention. Figure 17 shows details D of the electrical connection part of Figure 16. Specific details for implementing the invention

[0042] An electrical connection according to a preferred embodiment of the present invention is generally designated by reference numeral (10). The connection (10) includes a bushing (12) having a geometric central axis (14). The bushing (12) has the form of a hollow cylinder. Additionally, the connection (10) includes an electrical conductor (16) passing through the bushing (12) along the geometric central axis (14), and an insulating layer (18) electrically insulating the bushing (12) from the conductor (16). FIG. 1 illustrates an electrical connection (10) that is fully assembled and ready for use. FIG. 2 illustrates an exploded view of the electrical connection (10).

[0043] The bushing (12), the insulating layer (18), and the electrical conductor (16) are preferably rotationally symmetric with respect to the geometric central axis (14). In particular, in the cross-sectional view, the bushing (12), the insulating layer (18), and the electrical conductor (16) all have a circular or circular ring shape.

[0044] As schematically illustrated in FIG. 10, the electrical connection (10) may be installed in the jacket or casing (100) of the exhaust gas system of an internal combustion engine and electrically connected to an electrical component (102) placed in the jacket (100). An embodiment of FIG. 10 illustrates a specific type of electrical connection (10). Further embodiments will be described in more detail below. The electrical component (102) is preferably an electrically heatable grid or honeycomb body of a catalytic converter (104) intended to be supplied with current through the electrical conductor (16) of the electrical connection (10) after the installation of the electrical component (102). In FIG. 10, the catalytic converter (104) or its jacket (100) is each illustrated in a cross-sectional view to allow the interior portion of the jacket (100) to be seen. When in use, the catalytic converter (104) or its jacket (100) will each be sealed in an airtight manner to prevent exhaust gases from escaping from the interior portion of the jacket (100).

[0045] The electrical connection (10) is inserted into the mounting flange or opening (106) of the jacket (100), and the bushing (12) is secured to the mounting flange or opening (106), for example, by welding it to the jacket (100). Alternatively, the bushing (12) may also be secured to the mounting flange or opening (106) of the jacket (100) in any other way, for example, by threads, etc.

[0046] The inner end (inside the jacket (100)) of the electrical conductor (16) of the electrical connection (10) is connected to an electrical component (102). The outer end of the electrical conductor (16) opposite the electrical component (102) (outside the jacket (100)) may be connected to an electrical cable (not shown), etc. Preferably, a positive charge (+) is provided to the electrical conductor (16) of the electrical connection (10). The end of the cable opposite the electrical connection (10) may be connected to a power source (not shown), for example, a battery or a control unit of a vehicle, preferably to the positive terminal of the control unit or the battery.

[0047] Similarly, the inner end (not shown) of the electrical conductor of the other electrical connection is connected to the electrical component (102). The connection can be achieved directly or indirectly through the inner casing of the electrical component (102). The outer end of the electrical conductor of the remaining electrical connection opposite the electrical component (102) may be connected to an electrical cable (not shown), etc. Preferably, the electrical conductor (16) of the remaining electrical connection is provided with a negative charge (-) and is connected, for example, to a ground or earth terminal (e.g., vehicle body or vehicle chassis). The end of the remaining cable opposite the electrical connection may be connected to a power source (not shown), for example, a battery or a control unit of the vehicle, preferably to the negative terminal of the control unit or battery or to the ground or earth terminal. In the latter case, the negative terminal of the battery will be connected to the ground or earth terminal at some other point.

[0048] Finally, the electrical conductor of the additional electrical connection (not shown) performs only the function of an electrically isolated holding pin adapted to hold the inner casing of the electrical component (102) or the electrical component (102) itself inside the jacket (100). To this end, it is proposed that the inner end of the electrical conductor of the additional electrical connection be connected to the inner casing of the electrical component (102) or to the electrical component (102) itself. The connection is preferably electrically conductive and can be realized, for example, by welding, screw joining, or any other method. The electrical conductor of the additional electrical connection is electrically isolated from the bushing by an insulating layer. Thus, the additional electrical connection isolates the inner casing from the jacket (100).

[0049] Of course, the electrical connections (10) according to the present invention are not limited to the different uses described herein as examples. The electrical connections (10) may also be used in a number of other applications.

[0050] According to the present invention, the bushing (12), the insulating layer (18), and the electrical conductor (16) are compressed together by mechanical cold transformation. First, the bushing (12), the insulating layer (18), and the electrical conductor (16) are arranged coaxially with respect to the geometric central axis (14) of the bushing (12) (see FIG. 6). To this end, prior to mechanical cold transformation, the inner diameter of the inner circumferential surface (12a) of the bushing (12) is slightly larger than the outer diameter of the insulating layer (18). For example, the inner diameter of the bushing (12) may be approximately 0.1 mm larger than the outer diameter of the insulating layer (18) so that the bushing (12) can slide over the insulating layer (18). Similarly, the outer diameter of the outer circumferential surface (16b) of the electrical conductor (16) is slightly smaller than the inner diameter of the insulating layer (18), for example, about 0.1 mm smaller. After arranging the bushing (12), insulating layer (18) and electrical conductor (16) coaxially with respect to the geometric central axis (14) of the bushing (12), these components (12, 18, 16) are pressed together by mechanical cold transformation (see FIG. 7).

[0051] The bushing (12), the insulating layer (18), and the electrical conductor (16) are preferably compressed together during a rotary forging process to achieve mechanical cold transformation. Pressure is applied to the outer circumferential surface of the bushing (12) of the electrical connection (10). The pressure is preferably directed radially inward toward the geometric central axis (14). Due to the pressure and mechanical cold transformation, the original dimensions (diameter A and length B) of the electrical connection (10) change (diameter A1 and length B1). In particular, as shown in FIGS. 6 and 7, the diameter will decrease and the length will increase (A1 < A; B1 > B). Preferably, the change in dimensions applies to the bushing (12) and the insulating layer (18), while the electrical conductor (16) essentially retains its original dimensions.

[0052] The pressure applied to the electrical connection (10) can also modify the structure of the materials used for the bushing (12), the insulating layer (18), and the electrical conductor (16). In particular, the material of the insulating layer (18) and / or the bushing (12) can be hardened and / or the flexural fatigue strength can be increased due to the pressure applied to the electrical connection (10).

[0053] Due to mechanical cold transformation, the interconnection between the bushing (12) and the insulating layer (18), and between the insulating layer (18) and the electrical conductor (16), is greatly increased. The electrical connection (10) can absorb much higher force and torque values ​​without damage. In particular, the mechanical interconnection between the electrical conductor (16) and the insulating layer (18) and / or between the insulating layer (18) and the bushing (12) does not loosen or break even when high force and torque values ​​are applied to the electrical connection (10) during intended use.

[0054] The electric conductor (10) and its components (busing (12), insulating layer (18), and electric connector (16)) can each be manufactured from a special material and / or dimensioned so that the electric connector (10) can withstand up to 100 V DC and transmit up to 200 A. For this purpose, it is suggested that the diameter of the conductor (16) be 5.0 mm to 8.0 mm, preferably 6.0 mm to 7.5 mm. The outer diameter (A1) of the bushing (12) is determined by the intended use of the client and / or the electric connection (10).

[0055] In particular, the bushing (12) must fit neatly into the opening (106) inside the jacket or casing (100). A typical example for the outer diameter (A1) of the bushing (12) is 12.0 mm to 18.0 mm, preferably about 14.0 mm. In cross-section, the bushing (12) preferably has a thickness between the inner circumferential surface (12a) and the outer circumferential surface (12b) (see FIG. 2) of 1.0 mm to 5.0 mm, preferably about 2.0 mm. The thickness of the insulating layer (18) depends on the electrical or isolation properties achieved by the electrical connection (10), as well as the specified diameters of the electrical conductor (16) and the bushing (12). For example, the insulating layer (18) must achieve an insulation resistance of at least 10 MΩ at a 500 V DC voltage, preferably up to a few GΩ under ambient conditions. Depending on the material used for the insulating layer (18), the insulating layer has a thickness of at least 1.2 mm, preferably about 1.6 mm. Of course, these are merely exemplary values ​​adapted specifically for the use illustrated in FIG. 10. In other applications, one or more of the physical, mechanical, electrical and thermal values ​​and properties may vary much more significantly when using the electrical connection (10).

[0056] It is proposed that the electric conductor (16) have an outer surface (16b) having an arithmetic mean roughness of at least Ra = 1 μm (or greater) and / or protrusions and / or concaves (20) on at least a portion (16a) of the outer surface (16b), which is covered by an insulating layer (18) when assembled (see FIG. 2 to 4). The roughness of the outer surface (16b) is configured to provide protrusions (i.e., positive peaks) and / or concaves (i.e., negative peaks or troughs) (20) in an irregular distribution with respect to the average surface extension. The desired roughness can be achieved during the manufacture of the electric conductor (16), i.e., by machine turning, by reducing the rotational speed at which the outer surface (16b) is machined, for example, by a cutting or milling tool. In particular, if the rotational speed at which the outer surface (16b) is machined is reduced, the roughness of the outer surface (16b) of the electrical conductor (16) may increase. Alternatively, a desired roughness value may also be achieved by an additional process step after the manufacture of the electrical conductor (16).

[0057] During mechanical cold transformation, pressure is applied radially on the outer surface (12b) of the bushing (12). The bushing (12) transmits at least a portion of the radial pressure to an insulating layer (18) that is pressed onto the outer surface (16b) of the electrical conductor (16). A portion of the insulating material is pressed into the recesses (20) provided on the electrical conductor (16) and / or the protrusions (20) provided on the electrical conductor (16) are pressed into the insulating material of the insulating layer (18). Thus, an interlocking connection is established between the electrical conductor (16) and the insulating layer (18). This can further increase the force and torque values ​​that the electrical conductor (10) can absorb without damage. In particular, the mechanical interconnection between the electrical conductor (16) and the insulating layer (18) does not loosen or break even when high force and torque values ​​are applied to the electrical connection (10).

[0058] As illustrated in FIG. 8, the protrusions (20) preferably have a cross section having a base (22a) on the outer circumferential surface (16b) of the electrical conductor (16) and side walls (22b) extending from the ends of the base (22a) and preferably converging toward the top of the protrusion (20). Similarly, as illustrated in FIG. 9, the grooves (20) may have a cross section having an opening (24a) on the outer circumferential surface (16b) and side walls (24b) extending from the ends of the opening (24a) and preferably converging toward the bottom of the groove (20).

[0059] A preferred cross section for the grooves (20) is U-shaped so that the material of the insulating layer (18) can more easily enter and spread into the grooves (20) (see FIG. 9). Of course, the grooves (20) may also have any other cross section, such as a V-shaped cross section or a combination of U-shaped and V-shaped cross sections. In the case of roughness on the outer surface (16b) of the electric conductor (16), the grooves may have any irregular shape and position and may be distinguishable from one another.

[0060] A preferred cross section of the protrusions (20) is V-shaped so that the protrusions (20) enter more easily into the material of the insulating layer (18) (see FIG. 8). Of course, the protrusions (20) may also have any other cross section, such as a U-shaped cross section or a combination of U-shaped and V-shaped cross sections. In the case of roughness on the outer surface (16b) of the electrical conductor (16), the protrusions may have any irregular shape and position and may be distinguishable from one another.

[0061] The preferred depth of the concave portions (20) and the preferred height of the protrusions (20) may be 0.05 mm to 0.3 mm, preferably about 0.15 mm, with respect to the remaining outer surface (16b) of the electrical conductor (16). Of course, these are exemplary values ​​and may vary significantly in practice.

[0062] Additionally, it is proposed that the protrusions (20) and / or recesses (20) provided on the outer surface (16b) of the electrical conductor (16) have a circumferential longitudinal extension and / or an axial longitudinal extension. For example, as shown in FIG. 4, the protrusions or recesses (20a) may have a longitudinal extension that essentially extends circumferentially, i.e., around the geometric central axis (14) of the bushing (12). Alternatively, the protrusions or recesses (20b) may have a longitudinal extension that essentially extends axially, i.e. parallel to the geometric central axis (14) of the bushing (12). Furthermore, the protrusions and / or grooves (20) may have a longitudinal extension that extends circumferentially as well as axially. Thus, the protrusions and / or grooves (20) extend in an inclined or spiral (i.e., helical) manner on the outer surface (16b) of the electrical conductor (16) (not shown). Such protrusions and / or grooves (20) can be achieved during the manufacture of the electrical conductor (16), for example, by a specific feed rate relative to the rotational speed and a specific cutting depth of a cutting or milling tool that causes the outer surface (16b) to be machined. Alternatively, the protrusions and / or grooves (20) can also be achieved by an additional process step after the manufacture of the electrical conductor (16). Of course, it is also possible for a first group of protrusions and / or grooves (20a) to have a longitudinal extension in a first direction and a second group of protrusions and / or grooves (20b) to have a longitudinal extension in a second direction, and for the first group of protrusions and / or grooves (20a) to intersect with the second group of protrusions and / or grooves (20b) (see FIG. 4).

[0063] The protrusions or depressions (20) are preferably part of the ribbed outer surface (16a) of the electrical conductor (16) as illustrated in FIG. 4. The ribbed surface (16a) preferably comprises a plurality of grooves (20a, 20b). A first group of grooves (20a) extends parallel to each other, preferably at equal distances, and a second group of grooves (20b) extend parallel to each other, preferably at equal distances. The first group of grooves (20a) extends obliquely to the second group of grooves (20b), with an angle greater than 0° and less than 180°. Preferably, the angle between the first and second grooves (20a, 20b) is 90°, thereby creating a ribbed surface (16a) having a rectangle or square between the grooves (20a, 20b) (see FIG. 4). Alternatively, the angle is between 10° and 80°, preferably about 60°, to produce a ribbed surface (16a) having rhombuses between the grooves (20a, 20b) (see FIG. 13). Of course, instead of or additionally, the ribbed surface (16a) may also include protrusions.

[0064] In order to facilitate the material of the insulating layer (18) entering and spreading into the grooves (20) and / or facilitating the protrusions (20) entering into the material of the insulating layer (18), it is proposed that the insulating layer (18) be made of a material having a lower hardness than the material from which the electrical conductor (16) is made. Preferably, the material of the insulating layer (18) has a Mohs scale hardness of approximately 1.5 to 4.0, particularly 2.0 to 3.0. For comparison, gold has a Mohs scale hardness of approximately 2.5 to 3.0, copper coins have a hardness of approximately 3.0, and steel has a hardness of approximately 6.0 to 6.5. The material of the electrical conductor (16) has a greater hardness than the insulating material.

[0065] Additionally, it is proposed that the bushing (12), when assembled, have an inner surface (12a) having at least one of an arithmetic mean roughness of at least Ra = 1 μm (or greater), protrusions, and concaves (26) on at least a portion of the inner surface (12a) covering the insulating layer (18). Thus, the bushing (12) may have the form of a hollow cylinder, and the inner surface (12a) of the bushing (12) on which the insulating layer (18) is located comprises the desired roughness, protrusions, and / or concaves (26). The roughness of the inner surface (12a) is configured to provide protrusions (i.e., positive peaks) and / or concaves (i.e., negative peaks or troughs) in an irregular distribution with respect to the average surface extension. The desired roughness can be achieved during the manufacture of the bushing (12), i.e., by mechanical turning, by reducing the rotational speed at which the inner surface (12a) is machined, for example, by a cutting or milling tool. In particular, if the rotational speed at which the inner surface (12a) is machined is reduced, the roughness of the circumferential surface (12a) may be increased. Alternatively, the desired roughness value can also be achieved by an additional process step after the manufacture of the bushing (12).

[0066] During mechanical cold transformation, pressure is applied radially on the outer circumferential surface (12b) of the bushing (12). The inner circumferential surface (12a) of the bushing (12) is compressed radially onto the insulating layer (18). A portion of the insulating material of the insulating layer (18) is compressed into the recesses (26) provided on the inner circumferential surface (12a) of the bushing (12) and / or the protrusions (26) provided on the inner circumferential surface (12a) of the bushing (12) are compressed into the insulating material of the insulating layer (18). Thus, an interlocking connection is established between the bushing (12) and the insulating layer (18). This can further increase the force and torque values ​​that the electrical conductor (10) can absorb without damage. In particular, the mechanical interconnection between the bushing (12) and the insulating layer (18) does not loosen or break even when high force and torque values ​​are applied to the electrical connection (10).

[0067] Preferably, similar to the projections and grooves (20) of the electric conductor (16) as illustrated in FIGS. 8 and 9 and described above, the projections (26) of the inner circumferential surface (12a) of the bushing (12) have a cross section having side walls extending from the base and ends of the base on the inner circumferential surface (12a) of the bushing (12) and preferably converging toward the top of the projections (26). Similarly, the grooves (26) may have a cross section having side walls extending from the opening and ends of the opening on the inner circumferential surface (12a) and preferably converging toward the bottom of the groove.

[0068] A preferred cross-section for the grooves (26) is U-shaped so that the material of the insulating layer (18) can more easily enter and spread into the grooves (26). Of course, the grooves (26) may also have any other cross-section, such as a V-shaped cross-section or a combination of U-shaped and V-shaped. In the case of roughness on the inner circumferential surface (12a) of the bushing (12), the grooves may have any irregular shape and position and may be distinguishable from one another.

[0069] The preferred cross section of the protrusions (26) is V-shaped so that the protrusions (26) enter more easily into the material of the insulating layer (18). Of course, the protrusions (26) may also have any other cross section, such as a U-shaped cross section or a combination of U-shaped and V-shaped cross sections. In the case of roughness on the inner circumferential surface (12a) of the bushing (12), the protrusions may have any irregular shape and position and may be distinguishable from one another.

[0070] The preferred depth of the concave portions (26) and the preferred height of the protrusions (26) may be 0.05 mm to 0.3 mm, preferably about 0.15 mm, with respect to the remaining inner circumferential surface (12a) of the bushing (12). Of course, these are exemplary values ​​and may vary significantly in practice.

[0071] Additionally, it is suggested that the protrusions and / or recesses (26) provided on the inner circumferential surface (12a) of the bushing (12) have at least one of a circumferential extension and an axial extension. For example, the protrusions or recesses (26) may essentially have a longitudinal extension (not shown) extending circumferentially, that is, around the geometric central axis (14) of the bushing (12). Alternatively, the protrusions or recesses (26) may essentially have a longitudinal extension extending axially, that is, parallel to the geometric central axis (14) of the bushing (12) (see FIG. 2, FIG. 3, FIG. 5 and FIG. 12). Additionally, the protrusions and / or recesses (26) may have a longitudinal extension extending circumferentially as well as axially. Accordingly, the protrusions and / or grooves (26) extend in an inclined or spiral (i.e., helical) manner on the inner circumferential surface (12a) of the bushing (12) (not shown). Such protrusions and / or grooves (26) can be achieved during the manufacture of the bushing (12), for example, by a specific feed rate relative to the rotational speed and a specific cutting depth of a cutting or milling tool that causes the inner circumferential surface (12a) to be machined. Alternatively, the protrusions and / or grooves (26) can also be achieved by an additional process step after the manufacture of the bushing (12). Of course, it is also possible for a first group of protrusions and / or grooves (26) to have a longitudinal extension in a first direction and a second group of protrusions and / or grooves (26) to have a longitudinal extension in a second direction and for the first group of protrusions and / or grooves (26) to intersect with the second group of protrusions and / or grooves (26).

[0072] According to a preferred embodiment illustrated in FIGS. 2, 3, 5 and 12, the bushing (12) has recesses in the form of axial grooves (26) provided on the inner circumferential surface (12a) of the bushing (12) and spaced apart from each other in the circumferential direction. The grooves (26) may have longitudinal extensions that extend axially, that is, parallel to the geometric central axis (14) of the bushing (12). Preferably, the grooves (26) are spaced evenly apart from each other in the circumferential direction, that is, each is separated from neighboring grooves by a given angle. When the angle is 60°, there are six grooves (26) spaced evenly apart from each other on the inner circumferential surface (12a) of the bushing (12). Of course, different numbers of grooves (26) spaced evenly or unequally apart and different angles between the grooves (26) may also be provided.

[0073] Preferably, the axial grooves (26) do not extend along the entire axial extension of the inner circumferential surface (12a) of the bushing (12). Rather, it is proposed that the grooves (26) extend along only a portion of the inner surface (12a) of the bushing (12), starting from one end surface (12c) of the bushing (12) and ending before reaching the opposite end surface (12d) of the bushing (12). This can be seen in FIGS. 3 and FIGS. 5. Thus, the grooves (26) do not reach the opposite end surface (12d) of the bushing (12). This can additionally increase the force and torque values ​​that the electrical connection (10) can absorb without damage. In particular, a force F (see FIG. 3 and FIG. 12) acting on the electrical conductor (16) in a direction toward the opposite end surface (12d) of the bushing (12) will prevent the electrical conductor (16) from being pulled or compressed from the bushing (12) together with the insulating layer (18). The force F is also called the electrode displacement force. The electrode displacement force F is preferably greater than 5,000 N, particularly between 5,500 N and 10,000 N.

[0074] FIGS. 11 through 13 illustrate other preferred embodiments of an electrical connection (10) according to the present invention. In particular, in this embodiment, a first group of grooves (20a) are connected to a second group of grooves (20b) at a certain angle—the angle is 10° to 80°, preferably about 60°—to form a ribbed surface (16a) having rhombuses between the grooves (20a, 20b) (see FIG. 13). Of course, instead of or additionally to the grooves (20a, 20b), the ribbed surface (16a) may also include protrusions.

[0075] Of course, any other design may also be provided that the outer ribbed surface (16a) allows for mechanical form-matching interaction between the insulating layer (18) and the electrical conductor (16), thereby achieving interlocking connection between the two and improving the fixation of the insulating material (18) on the outer surface (16b) of the electrical conductor (16).

[0076] It can be seen in FIG. 11 that the ribbed surface (16a) has an axial extension larger than the insulating layer (18) and the bushing (12). This allows for the correct positioning of the electrical conductor (16) relative to the bushing (12) during the manufacturing process before the bushing (12), insulating layer (18), and electrical conductor (16) are compressed together by mechanical cold transformation.

[0077] FIGS. 14 and 15 illustrate the electrical connection (10) of FIGS. 11 through 13 fixed to an opening (106) of an exhaust gas system of, for example, an internal combustion engine, in a jacket or casing (100). The electrical connection (10) may be fixed to the opening (106) by welding, screw fastening, or similar connecting techniques. In FIGS. 14 and 15, a weld bead (110) is visible. Alternatively or additionally, the electrical connection (10) may also be provided with a radially protruding collar (not shown) that rests on the outer surface of the jacket (100) when the electrical connection (10) is introduced into the opening (106). The collar may additionally support a hermetic fixation of the electrical connection (10) in the opening (106) of the jacket (100).

[0078] FIGS. 16 and 17 illustrate another embodiment of an electrical connection (10) fixed to a jacket or casing (100), e.g., an opening (106) of an internal combustion engine's exhaust system. The ribbed outer surface (16) may include grooves (20) extending around the entire or part of the circumference of the outer surface (16b) of the electrical conductor (16). The grooves (20) may be annular or spiral in shape. The electrical connection (10) may be fixed to the opening (106) by welding, screw fastening, or similar connection techniques. In FIGS. 16 and 17, the electrical connection is fixed within the hole by a screw. For this purpose, a male screw is provided on the outer surface (12b) of the bushing (12) or at least a part thereof. A corresponding female screw may be provided in the opening (106). Alternatively or additionally, the electrical connection (10) may also be provided with a radially protruding collar (not shown) that is placed on the outer surface of the jacket (100) when the electrical connection (10) is introduced into the opening (106). The collar may additionally support the hermetic fixation of the electrical connection (10) in the opening (106) of the jacket (100).

[0079] To facilitate the material of the insulating layer (18) entering and spreading into the grooves (26) and / or the protrusions (26) entering into the material of the insulating layer (18), it is suggested that the insulating layer (18) be made of a material having a lower hardness than the material from which the bushing (12) is made. Preferably, the material of the insulating layer (18) has a Mohs scale hardness of approximately 1.5 to 4.0, particularly 2.0 to 3.0. The material of the bushing (12) has a greater hardness than the insulating material.

[0080] It is suggested that at least one of the bushing (12) and / or the electrical conductor (16) be made of stainless steel, in particular a nickel-chromium-iron alloy. The material of the bushing (12) and / or the electrical conductor (16) may comprise at least 70% nickel (+ cobalt), 10-20% chromium, and 3-15% iron. In addition to these components, the material may further comprise small amounts (< 2%) of carbon, manganese, sulfur, silicon, and / or copper. Preferably, the material of the bushing (12) and / or the electrical conductor (16) comprises at least 72% nickel (+ cobalt), 14-17% chromium, and 6-10% iron. It may be advantageous for both the bushing (12) and the electrical conductor (16) to be made of the same material. In principle, any material adapted to provide the necessary physical, mechanical, electrical, and thermal properties required for the electrical connection (10) can be used for the bushing (12) and the electrical conductor (16).

[0081] Additionally, it is suggested that the insulating layer (18) be made of a material containing at least 50% phyllosilicate mineral. Preferably, the insulating material contains more than 70%, particularly about 90%, phyllosilicate mineral. The remaining material of the insulating layer (18) may be a laminate or bonding material. Preferably, the material of the insulating layer (18) is less hygroscopic than magnesium oxide (MgO). In principle, any material adapted to provide the necessary physical, mechanical, electrical, and thermal properties required for the electrical connection (10) may be used for the insulating layer (18). In particular, the material must be sufficiently elastic to compensate for the thermal expansion of the different materials used in the electrical connection (10) due to wide thermal fluctuations (over 1,000°K) during the intended use of the electrical connection (10) without breakage or cracking. Thus, a high degree and long-lasting airtightness of the electrical connection (10) can be ensured.

[0082] In summary, the present invention has the following particular advantages:

[0083] - When the bushing (12) is welded to the jacket or casing (100), the insulation layer (18) will not be damaged or cracked due to the different thermal shrinkage values ​​of the material of the bushing (12) and the material of the insulation layer (18). High levels of electrical insulation characteristics and airtightness of the electrical connection (10) are achieved. The insulation resistance is greater than 10 MΩ at a voltage of 500 V DC and may reach values ​​of up to several GΩ.

[0084] - During use of the electrical connection (10), the temperature may fluctuate between the ambient temperature (up to 40°C) when the combustion engine and catalytic converter (104) are turned off and cooled, and up to about +1,000°C when the combustion engine and catalytic converter (104) are in operation (this results in a temperature change of more than 1,000°K). The electrical connection (10) can withstand such large temperature fluctuations without negatively affecting the physical, mechanical, electrical and thermal properties and the properties of the electrical connection (10).

[0085] - The electrical connection (10) can withstand very high force and torque values ​​applied thereto. In particular, the mechanical interconnection between the electrical conductor (16) and the insulating layer (18) and / or between the insulating layer (18) and the bushing (12) will not loosen or break due to the large force and / or torque values ​​acting on the electrical connection (10). The electrical connection (10) can withstand a breaking torque of more than 15 Nm, preferably more than 16 Nm, particularly preferably more than 17 Nm, particularly about 20 Nm.

[0086] - The sealing effect of the electrical connection (10) is particularly high due to the improved mechanical interconnection of the insulating layer (18) toward the electrical conductor (16) and / or bushing (12). Leakage of a small amount of gas or fluid (e.g., exhaust gas) from the inside of the jacket or casing (100) across the electrical connection (10) to the environment is allowed. The present invention significantly reduces the amount of leakage. The electrical connection (10) achieves a leakage value of less than 20 ml / min at a pressure of 0.3 bar.

Claims

Claim 1 An electrical connection part (10) comprising a bushing (12) having a geometric central axis (14), an electrical conductor (16) passing through the bushing (12) along the geometric central axis (14), and an insulating layer (18) electrically insulating the bushing (12) from the conductor (16), wherein the bushing (12), the insulating layer (18), and the electrical conductor (16) are compressed together by mechanical cold transformation. Claim 2 In claim 1, the electrical conductor (16) has an external circumferential surface (16b) having at least one of protrusions and concaves (20; 20a, 20b) on at least a portion (16a) of the external circumferential surface (16b) of the electrical conductor (16) which is covered by the insulating layer (18), an electrical connection (10). Claim 3 In claim 2, at least one of the protrusions and concave portions (20; 20a, 20b) has at least one of a circumferential extension and an axial extension, an electrical connection portion (10). Claim 4 In claim 2, the protrusions or concave portions (20; 20a, 20b) are part (16a) of the ribbed external circumferential surface (16b) of the electrical conductor (16) having a plurality of grooves, an electrical connection portion (10). Claim 5 In claim 1, the electrical connection part (10) is made of a material having a lower hardness than the material on which the electrical conductor (16) is made. Claim 6 In claim 1, the bushing (12) has an electrical connection (10) having an inner surface (12a) having at least one of an arithmetic mean roughness of at least Ra = 1 μm and concave portions (26) on at least a part of the inner surface (12a) of the bushing (12) covering the insulating layer (18). Claim 7 In claim 6, at least one of the concave portions (26) of the inner surface (12a) has at least one of a circumferential extension and an axial extension, an electrical connection portion (10). Claim 8 In claim 6, the above bushing (12) is an electrical connection part (10) having concave portions (26) in the form of axial grooves spaced apart from each other in the circumferential direction. Claim 9 In claim 8, the electrical connection portion (10) extends on a portion of the inner circumferential surface (12a) of the bushing (12) such that the axial grooves start at one end surface (12c) of the bushing (12) and end at the opposite end surface (12d) of the bushing (12). Claim 10 In claim 1, the electrical connection part (10) is made of a material having a lower hardness than the material on which the bushing (12) is made. Claim 11 In claim 1, the electrical connection part (10), wherein at least one of the bushing (12) and the electrical conductor (16) is made of stainless steel. Claim 12 In claim 1, the electrical connection (10), wherein the insulating layer (18) is made of a material comprising at least 50% phyllosilicate mineral. Claim 13 A process for manufacturing an electrical connection (10), wherein the electrical connection (10) comprises a bushing (12) having a geometric central axis (14), an electrical conductor (16) passing through the bushing (12) along the geometric central axis (14), and an insulating layer (18) electrically insulating the bushing (12) from the conductor (16), wherein the bushing (12), the insulating layer (18), and the electrical conductor (16) are arranged coaxially with respect to the geometric central axis (14) and then compressed together by mechanical cold transformation. Claim 14 In claim 13, the process for manufacturing an electrical connection (10) wherein the bushing (12), the insulating layer (18), and the electrical conductor (16) are compressed together during a rotary forging process. Claim 15 A process for manufacturing an electrical connection part (10), comprising an electrical connection part (10) according to claim 13. Claim 16 An exhaust gas system for an internal combustion engine comprising an electrical connection (10) and a jacket (100) having at least one opening (106), wherein the electrical connection (10) comprises a bushing (12) having a geometric central axis (14), an electrical conductor (16) passing through the bushing (12) along the geometric central axis (14), and an insulating layer (18) electrically insulating the bushing (12) from the conductor (16), wherein the electrical connection (10) is introduced into the jacket (100) through the opening (106) and fixedly attached to the jacket (100), and wherein the exhaust gas system comprises the electrical connection (10) according to claim 1. Claim 17 In claim 16, the electrical conductor (16) of the electrical connection part (10), which is introduced into the jacket (100) through the opening (106) and fixedly attached to the jacket (100), is electrically connected to an electrical component (102) located inside the jacket (100), in an exhaust gas system. Claim 18 In claim 16 or 17, the exhaust gas system comprises a catalytic converter (104), the jacket (100) is part of the catalytic converter (104) and houses an electrical component (102) in the form of an electrically heatable grid or honeycomb body, and the electrical conductor (16) of the electrical connection (10) introduced into the jacket (100) through the opening (106) and fixedly attached to the jacket (100) is electrically connected to the grid or honeycomb body inside the jacket (100). Claim 19 In claim 1, the electrical connection part (10), wherein at least one of the bushing (12) and the electrical conductor (16) is made of a nickel-chromium-iron alloy.

Images