Connection pin

Abstract

A connecting pin, in particular for a connection unit for electrically contacting a heating conductor of an exhaust gas heater of an exhaust system of an internal combustion engine, comprises a pin body (38) elongated in the direction of a pin body longitudinal axis (L) with an outer connection area (44) for connecting a power supply line (26, 28) to the connecting pin (36), a cooling area (54), a feedthrough area (40) for electrically insulated passage of the pin body (38) through a pin carrier (30) of a connection unit (22, 24) and an inner connection area (42) for connecting the connecting pin (36) to a heating conductor (16) of an exhaust gas heater (14), wherein a cooling surface formation (56) in the form of ribs (62) or groove-like recesses, which increase the surface area for enhanced thermal cooling, is provided in the cooling area (54).

Description

[0001] The present invention relates to a connection pin which is used, for example, in a connection unit for electrically contacting a heating conductor of an exhaust gas heater of an exhaust system of an internal combustion engine in order to electrically contact an exhaust gas heater arranged in an exhaust gas guide component and around which an exhaust gas flow of an internal combustion engine guided in the exhaust gas guide component can flow.

[0002] The connection units used in connection with exhaust systems of internal combustion engines comprise a generally one-piece connection pin which is electrically insulated and carried in a pin carrier and is supported via the pin carrier on an exhaust gas routing component, for example an exhaust pipe or a housing carrying the exhaust gas. The connection pin projects with an inner connection region into the interior volume of the exhaust gas routing component and is electrically connected in this inner connection region to a heating conductor connection region of a heating conductor of such an exhaust gas heater, for example by soldering. In an outer connection region located outside the exhaust gas routing component, the connection pin can be connected to a voltage source via a cable or the like.

[0003] When an internal combustion engine is operating, the various components of an exhaust system heat up due to the exhaust gas flowing through them. The operation of the exhaust gas heater also heats up the various components conducting the heating current, particularly the terminal units used for the electrical connection to the exhaust heater's heating conductor, or their terminal pins. This also heats up a cable connected to such a terminal pin in the outer connection area. This cable generally has an electrically conductive core and a surrounding sheath made of electrically insulating material, such as plastic. Excessive heating of the cable can damage the sheath and, in extreme cases, even cause it to ignite.

[0004] A terminal pin according to the preamble of claim 1 is known from DE 695 01 049 T2. In this known terminal pin, a cooling element is arranged on the cooling area, comprising a ring-like cooling element body surrounding the cooling area of ​​the terminal pin and a plurality of disc-like cooling fins arranged successively in the direction of a pin body longitudinal axis of the terminal pin and extending radially outward from the cooling element body.

[0005] It is the object of the present invention to provide a connection pin, in particular for a connection unit for electrically contacting a heating conductor of an exhaust gas heater of an exhaust system of an internal combustion engine, in which excessive thermal stress on components in contact therewith is avoided.

[0006] According to the invention, this object is achieved by a connection pin, in particular for a connection unit for electrically contacting a heating conductor of an exhaust gas heater of an exhaust system of an internal combustion engine, comprising a pin body elongated in the direction of a pin body longitudinal axis with: an outer connection area for connecting a power supply line to the terminal pin, a cooling area, a feed-through area for electrically insulated passage of the pin body through a pin carrier of a connection unit, an inner connection area for connecting the terminal pin to a heating conductor of an exhaust gas heater, wherein a cooling surface formation is provided in the cooling area.

[0007] The cooling surface formation comprises a plurality of cooling fins which follow one another at a mutual distance in the circumferential direction around the longitudinal axis of the pin body and preferably extend substantially in the direction of the longitudinal axis of the pin body.

[0008] By providing the cooling surface formation, an enlarged surface is created on the terminal pin, through which heat absorbed or generated in the terminal pin can be dissipated to the environment. Overheating, for example, of a cable connected to such a terminal pin can thus be prevented.

[0009] In order to be able to design such a cooling surface formation in an optimized manner independently of the structure of the connecting pin, it is proposed that at least part of the cooling surface formation is formed on a cooling element fixed in the cooling region on the pin body.

[0010] An easy-to-implement, yet stable connection of the cooling element to the pin body can be achieved, for example, by securing the cooling element to the cooling area by press fitting and / or material bonding.

[0011] A large surface available for the dissipation of heat can be provided, for example, in that the cooling element comprises an annular cooling element body surrounding the cooling region and a plurality of cooling fins extending radially outward from the cooling element body.

[0012] In addition, the cooling surface formation can comprise a plurality of cooling fins which follow one another at a mutual distance in the direction of the pin body longitudinal axis and surround the pin body longitudinal axis in a ring-like manner.

[0013] To further increase the surface area usable for heat dissipation, the thickness of at least one, preferably each, cooling fin can increase in the radially outward direction.

[0014] If the cooling area is designed to widen radially in the direction of the feedthrough area, the cooling element body of the cooling element can be pressed onto this radially widening cooling area when the cooling surface formation is provided on a cooling element.

[0015] In a further embodiment, at least part of the cooling surface formation can be formed as an integral part of the cooling region.

[0016] In order to obtain this structure of the cooling surface formation integrated into the cooling region, it is proposed that the cooling surface formation comprises at least one groove-like depression, preferably a plurality of groove-like depressions arranged at a mutual distance from one another, in the cooling region.

[0017] For example, at least one groove-like depression can preferably be designed to completely surround the pin body longitudinal axis and / or at least one groove-like depression can preferably be designed to extend substantially in the direction of the pin body longitudinal axis.

[0018] In order to achieve a shielding effect, in particular for the connecting pin in a pin carrier made of electrically insulated, for example ceramic insulating material, by means of the cooling surface formation, it is proposed that the cooling region is arranged in the direction of the pin body longitudinal axis between the outer connection region and the feedthrough region.

[0019] The invention further relates to a connection unit for electrically contacting a heating conductor of an exhaust gas heater of an exhaust system of an internal combustion engine, comprising a connection pin designed according to the invention and carried in an electrically insulated manner on a pin carrier.

[0020] The terminal pin can be supported on the pin carrier by preferably ceramic insulating material.

[0021] Furthermore, the invention relates to an exhaust system for an internal combustion engine, comprising an exhaust gas heater arranged in an exhaust gas guide component with a heating conductor with at least one heating conductor connection area, preferably two heating conductor connection areas, wherein a connection unit constructed according to the invention is provided in association with at least one heating conductor connection area, preferably each heating conductor connection area, wherein the pin carrier of the connection unit is fixed to the exhaust gas guide component and the connection pin of the connection unit passes through an opening provided in the exhaust gas guide component and is electrically conductively connected in its inner connection area to a heating conductor connection area of ​​the heating conductor.

[0022] The invention is described in detail below with reference to the accompanying figures. They show: Fig. 1 is a perspective view of a section of an exhaust system for an internal combustion engine with an exhaust gas heater and connection units associated with a heating conductor of the exhaust gas heater; Fig. 2 is a partial longitudinal sectional view of the Fig. 1 shown section of an exhaust system with connection units not according to the invention; Fig. 3 one of the Fig. 2 corresponding partial longitudinal sectional view of another embodiment of a connection unit not according to the invention; Fig. 4 a perspective view of another embodiment of a connection unit not according to the invention; Fig. 5 a perspective view of another embodiment of a connection unit not according to the invention.

[0023] The Fig. 1 und 2 show a section of an exhaust system, generally designated 10, of an internal combustion engine for a motor vehicle. The exhaust system 10 comprises a tubular exhaust gas guide component 12, in the interior volume of which an exhaust gas flow emitted by an internal combustion engine is guided. An exhaust gas heater 14, only partially shown, is arranged in the exhaust gas guide component 12. The exhaust gas heater 14 comprises a heating conductor 16, constructed from flat material in the illustrated embodiment, with two heating conductor connection areas 18, 20. In each of the heating conductor connection areas 18, 20, the heating conductor 16, which is composed, for example, of several parts, is electrically connected via connection units 22, 24, for example identical in construction, to cables 26, 28 used as voltage supply lines leading to a voltage source.

[0024] Each of the two connection units 22, 24, which are preferably identical in construction, comprises a pin carrier 30, for example, constructed of metal material, which is fixed in the region of a through-opening 32 of the exhaust gas guide component 12 on the outer surface thereof, for example by welding or soldering to produce a gas-tight seal. A connection pin, generally designated 36, is carried in the pin carrier 30 and electrically insulated therefrom by electrically insulating material 34, for example ceramic material. The connection pin 36 has a pin body 38, for example constructed in one piece or possibly composed of several parts, which is elongated in the direction of a pin body longitudinal axis L. In its through-passage area 40 penetrating the pin carrier 30, the pin body 38 is carried on the pin carrier 30 by means of the electrically insulating material 34. It should be noted that in the Fig. 2 In the embodiment shown, for example, the feedthrough region 40 can be embedded in the electrically insulating material and can thus be fixed to the pin carrier 30. Other configurations are also conceivable in which the feedthrough region 40 is supported on the pin carrier 30 with respect to the pin carrier 30 via disc-like elements made of the electrically insulating material and prestressing elements or the like inserted therein.

[0025] In its inner connection area 42 extending inside the exhaust gas guide component 12, the pin body 38 or the connection pin 36 is connected to one of the heating conductor connection areas 18, 20, in which Fig. 2 The example shown of the connection unit 22 is mechanically stable and electrically conductively connected to the heating conductor connection area 18, for example by soldering or welding.

[0026] In its outer connection area 44 facing away from the inner connection area 42 or at the other axial end of the pin body 38, the pin body 38 or the connecting pin 36 in the case of the Fig. 2 The connection unit 22, shown in more detail, is connected to the cable 26. The cable 26 has a core 46, which is constructed, for example, from copper or other electrically conductive material, and a sheath 48 surrounding the core 46 and made of electrically insulating material, for example plastic. For connection to the connection pin 36, the cable 26 has a connection element 50 which engages around the sheath 48 in a clamp-like manner and is thus firmly connected to it. The end region of the core 46 protruding beyond the sheath 48 is electrically conductively connected to the connection element 50, for example by clamping and / or soldering. The connection element 50 further has a sleeve-like connection region 52 which is pressed onto the outer connection region 44 of the pin body 38 in the direction of the pin body longitudinal axis L and is thus connected to it in an electrically conductive and mechanically stable manner.For this purpose, the pin body 38 can be configured to widen radially, for example conically, toward the inner connecting region 42, at least in its longitudinal section providing the outer connecting region 44, so that a stable connection is achieved by pressing on the connecting element 50. Alternatively or additionally, the connecting region 52 could be secured to the outer connecting region 44 by a fastening element, such as a nut or the like screwed onto the outer connecting region, and / or by a material connection to the outer connecting region 44.

[0027] Between the outer connection region 44 and the feedthrough region 40, the pin body 38 or the connecting pin 36 has a cooling region, generally designated 54. In the cooling region 54, a cooling surface formation, generally designated 56, is provided on the connecting pin 36, which provides a comparatively large surface for thermal interaction with the ambient air surrounding the connecting pin 36. In particular, such a cooling surface formation 56, described below in various embodiments, is characterized in that it has a larger outer surface for thermal interaction with the ambient air than a connecting pin 36 constructed with a purely cylindrical outer surface in this length range, i.e., the cooling region 54.

[0028] In the Fig. 1 und 2 In the embodiment example shown, the cooling surface formation 56 is provided on a cooling element 58 that is separate from the pin body 38, i.e., designed as an independent component. The cooling element 58, which is constructed, for example, from metal material, has a sleeve-like cooling element body 60, which has a preferably ring-like closed structure and surrounds the cooling region 54 of the pin body 38. The cooling element 58 can be secured to the pin body 38 by a press fit. For this purpose, the pin body 38 could, for example, also be designed to widen radially in its cooling region 54 in the direction of the inner connecting region 42, for example conically. Alternatively or additionally, it is also possible to provide a material-locking connection between the pin body 38 and the cooling element body 60, for example by welding, soldering, or gluing. A connection by form-fitting, for example screwing, is also possible.

[0029] The cooling element 58 has heat transfer fins 62 extending radially outward from the cooling element body 60 and surrounding the cooling element body 60 or the pin body's longitudinal axis L in a ring-like manner. The ring-like or plate-like cooling fins 62, which are arranged one after the other in the direction of the pin body's longitudinal axis 38, form ring-like or groove-like depressions 64 between them. This structure of cooling fins 62, which are arranged at a distance from one another and follow one another in the direction of the pin body's longitudinal axis L, provides a very large surface area. At this surface, heat generated in the pin body 38 or the connection pin 36 by the electrical current flowing therein, or heat transferred to it by the exhaust gas flowing around the inner connection area 42, can be dissipated to the air surrounding the cooling element 58. Excessive heating of the cable 26 or 28 connected to a respective connection unit 22 or 24 can thus be avoided.

[0030] A further embodiment of such a connection unit or a connection pin therefor, not according to the invention, is shown in Fig. 3 Components previously described with reference to the Fig. 1 und 2 Components described correspond in terms of structure or function are designated by the same reference numerals.

[0031] The one in Fig. 3 In the connection unit 22 shown, the cooling surface formation 56 forms an integral part of the pin body 38 in its cooling region 54. In this embodiment, too, the cooling surface formation 56 comprises a plurality of cooling fins 62 surrounding the pin body longitudinal axis L in a ring-like manner, with ring-like or groove-like depressions 64 formed between them. In this embodiment, too, the provision of the plurality of cooling fins 62 following one another in the direction of the pin body longitudinal axis L provides a comparatively large surface area at which heat can be transferred to the air surrounding the pin body 38.

[0032] A connection unit 22 according to the invention is shown in Fig. 4 shown. In the Fig. 4 In the connection unit 22 shown, the cooling surface formation 56 comprises a cooling element 58 designed as a separate component with a cooling element body 60 surrounding the cooling area 54 of the pin body 54 in a ring-like manner. A plurality of cooling fins 62 extend radially outwards from the cooling element body 60, so that a fan-like or, in axial view, star-like structure is formed by cooling fins 62 which are elongated in the direction of the pin body longitudinal axis L and which form spaces 64 between them.

[0033] In Fig. 4 It can be seen that the fin thickness, i.e., the dimension of the cooling fins 62 in the circumferential direction, increases from the radially inner to the radially outer side. This results in the cooling fins 62 providing comparatively large end faces 66 in their radially outer end regions, which also contribute to the surface area usable for dissipating heat to the ambient air.

[0034] A further embodiment not according to the invention with a cooling surface formation 56 provided as an integral part of the cooling area 54 of the pin body 38 is shown in Fig. 5 shown. In this embodiment, the cooling surface formation 56 comprises two groove-like depressions 68, 70 provided at an axial distance in the cooling region 54, preferably surrounding the pin body's longitudinal axis L in a ring-like manner without interruption. These groove-like depressions 68, 70, which are located at a greater axial distance from one another, also contribute to enlarging the surface area of ​​the pin body 38 in its cooling region 54 and thus to an increased thermal interaction with the ambient air.

[0035] It should be noted that, for example, in the Fig. 5 In the embodiment example shown, such groove-like depressions could also be formed extending in the direction of the pin body longitudinal axis L. For example, axially extending groove-like depressions could also be formed between the two groove-like depressions 68, 70 surrounding the pin body longitudinal axis L in a ring-like manner, as in Fig. 5 illustrated by the groove-like depression 72 shown with dashed lines.

[0036] By providing a cooling surface formation that increases the surface area available for thermal interaction with the ambient air, efficient dissipation of heat generated in or transferred to the terminal pin 38 to the outside is ensured, so that, in particular, thermal overload of a cable connected to such a terminal pin 36 can be avoided. The dimensioning of the cooling surface formation, for example, the number of cooling fins or groove-like depressions, can be adjusted depending on the expected amount of heat to be dissipated to the environment. For this purpose, the axial extension, the radial extension, and also the number of cooling fins or groove-like depressions can be selected accordingly.In principle, the cooling fins can also be designed in the form of rod-like or pin-like projections extending from the radially inside to the radially outside, which can, for example, be arranged consecutively in a ring-like structure in the circumferential direction around the longitudinal axis of the pin body and / or consecutively in a linear structure in the direction of the longitudinal axis of the pin body. Such structures, which increase the surface area available for dissipating heat to the environment, can also be contours that occur during production, such as wave undercuts or draft angles when the pin body is manufactured as a cast part.

[0037] It is also possible to combine different configurations. For example, one or more cooling elements can have both axially extending cooling fins, as in Fig. 4 shown, as well as ring-like cooling fins, as in Fig. 2shown. Even when the cooling surface formation is provided as an integral component of the connecting pin 38, such a combination of different types of cooling fins or structures serving to provide a larger heat transfer surface, such as groove-like depressions, is possible.

Claims

1. A terminal pin, in particular for a terminal unit for the electrical contacting of a heating conductor of an exhaust-gas heater of an exhaust-gas system of an internal combustion engine, comprising a pin body (38) which is elongate in the direction of a pin body longitudinal axis (L) and which has: - an outer connection region (44) for the connection of a voltage supply line (26, 28) to the terminal pin (36), - a cooling region (54), - a leadthrough region (40) for the electrically insulated leadthrough of the pin body (38) through a pin support (30) of a terminal unit (22, 24), - an inner connection region (42) for the connection of the terminal pin (36) to a heating conductor (16) of an exhaust-gas heater (14), wherein a cooling surface formation (56) is provided in the cooling region (54), characterized in that the cooling surface formation (56) comprises a plurality of cooling fins (62) which follow one another with a mutual spacing in the circumferential direction around the pin body longitudinal axis (L).

2. The terminal pin as claimed in claim 1, characterized in that at least a part of the cooling surface formation (56) is formed on a cooling element (58) that is fixed to the pin body (38) in the cooling region (54).

3. The terminal pin as claimed in claim 2, characterized in that the cooling element (58) is fixed to the cooling region (54) by way of an interference fit and / or material cohesion.

4. The terminal pin as claimed in claim 2 or 3, characterized in that the cooling element (58) comprises an annular cooling element body (60), which surrounds the cooling region (54), and a plurality of cooling fins (62), which extend radially outward from the cooling element body (60).

5. The terminal pin as claimed in any one of claims 1-4, characterized in that the cooling surface formation (56) comprises a plurality of cooling fins (62) which follow one another with a mutual spacing in the direction of the pin body longitudinal axis (L) and which annularly surround the pin body longitudinal axis (L).

6. The terminal pin as claimed in any one of claims 1-5, characterized in that the plurality of cooling fins (62) which follow one another with a mutual spacing in a circumferential direction around the pin body longitudinal axis (L) extend substantially in the direction of the pin body longitudinal axis (L).

7. The terminal pin as claimed in any one of claims 1-6, characterized in that, in the case of at least one, preferably each cooling fin (62), a fin thickness increases in a radially outward direction.

8. The terminal pin as claimed in any one of claims 1-7, characterized in that the cooling region (54) is configured to widen radially in the direction of the leadthrough region (40).

9. The terminal pin as claimed in any one of claims 1-8, characterized in that at least a part of the cooling surface formation (56) is configured as an integral part of the cooling region (54).

10. The terminal pin as claimed in claim 9, characterized in that the cooling surface formation (56) comprises at least one groove-like indentation (68, 70), preferably a plurality of groove-like indentations (68, 70, 72) which are arranged with a mutual spacing to one another, on the cooling region (54).

11. The terminal pin as claimed in claim 10, characterized in that at least one groove-like indentation (68, 70) configured to preferably fully encircle the pin body longitudinal axis (L), and / or in that at least one groove-like indentation (72) is configured to extend preferably substantially in the direction of the pin body longitudinal axis (L).

12. The terminal pin as claimed in any one of claims 1-11, characterized in that the cooling region (54) is arranged, in the direction of the pin body longitudinal axis (L), between the outer connection region (44) and the leadthrough region (40).

13. A terminal unit for the electrical contacting of a heating conductor of an exhaust-gas heater of an exhaust-gas system of an internal combustion engine, comprising a terminal pin (36) as claimed in any one of the preceding claims, which is supported in electrically insulated fashion on a pin support (30).

14. The terminal unit as claimed in claim 13, characterized in that the terminal pin (36) is supported on the pin carrier (30) by way of preferably ceramic insulating material (34).

15. An exhaust-gas system for an internal combustion engine, comprising an exhaust-gas heater (14) which is arranged in an exhaust-gas guiding component (12) and which has a heating conductor (16) with at least one heating conductor connection region (18, 20), preferably two heating conductor connection regions (18, 20), wherein a terminal unit (22, 24) as claimed in claim 13 or 14 is assigned to at least one heating conductor connection region (18, 20), preferably each heating conductor connection region (18, 20), wherein the pin support (30) of the terminal unit (22, 24) is fixed to the exhaust-gas guiding component (12), and the terminal pin (36) of the terminal unit (22, 24) extends through an opening (32) provided in the exhaust-gas guiding component (12) and, in its inner connection region (42), is connected in electrically conductive fashion to a heating conductor connection region (18, 20) of the heating conductor (16).

Images