Electrode and spacer element

Abstract

The invention relates to a heating resistor (1) for insertion into an exhaust pipe (4), wherein the heating resistor (1) is formed into a shape with multiple mutually adjacent heating loops (1.3) which form a basic shape_G, wherein each heating loop (1.3) is formed from two strips, a strip_1 and a strip_2, wherein adjacent strips (1.2a, 1.2b) of the heating loops (1.3) are separated by a groove (1.1) having a groove axis (1.1a), wherein at least one strip_1 has a receiving opening (1.4a) having a cross-sectional shape_A for receiving an insulator (2), wherein the adjacent strip_2, in the region of the receiving opening (1.4a), a) is flat or b) has a contact surface (1.4b) with a cross-sectional shape_F that differs from the cross-sectional shape_A.

Description

[0001] Electrode and spacer element

[0002] The invention relates to a heating resistor for insertion into an exhaust pipe for heating exhaust gas, wherein the heating resistor has a basic shape_G in which one or more heating loops arranged next to one another are provided, which form the basic shape_G, wherein the respective heating loop is formed from two webs coupled at the ends, a web_1 and a web_2, wherein adjacent webs of the heating loop or adjacent webs of the heating loops are separated by a groove with a groove axis or a gap.

[0003] A heating resistor with a spacer element is already known from US 5,501,842 A. The heating resistor has transverse slots into which insulator elements are inserted.

[0004] The invention is based on the object of designing and arranging a heating resistor so that the continuous load capacity is increased.

[0005] The object is achieved according to the invention in that at least one web_1 has a receiving opening with a cross-sectional shape_A for receiving an insulator, wherein the adjacent web_2 in the region of the receiving opening is a) flat or b) has a contact surface with a cross-sectional shape_F that is different from the cross-sectional shape_A. The cross-sectional shape_A or the cross-sectional shape_F can be round, oval, polygonal, or angular.

[0006] The different design of the contact surface on the adjacent web_2 in the area of ​​the receiving opening prevents a positive connection between the insulator and the web_2, so that the insulator can be moved in both directions with respect to the web_2 and with respect to the slot axis. This enables low-stress relative movement between the insulator and the web_2 when the heating resistor is heated. Relative movement between the web_1 and the insulator is not provided. The same is achieved if a receiving opening with a cross-sectional shape_F is provided as the contact surface, whereby the cross-sectional shape_F deviates so far from the cross-sectional shape_A or is larger than the cross-sectional shape_A that, when insulators are used, a stress-free relative movement between the web_2 and the insulator in the direction of the slot axis is possible.The respective insulator can be inserted into the receiving opening in the direction of the main exhaust gas flow, i.e., perpendicular to the surface of the heating resistor. With respect to the three translational spatial axes, there is at least one bivalent bearing between the insulator and web_1. However, the insulator can be brought into contact with web_2 at least in a direction perpendicular to the groove axis or perpendicular to the exhaust gas flow.

[0007] It can also be advantageous for the receiving opening to have two flanks that ensure a positive connection with an insulator inserted into the receiving opening in the direction of the groove axis. The insulator can be placed in a positive-locking manner against the web_1 with respect to a spatial axis running parallel to the groove axis. Thus, a positive connection can be established between the insulator and the web_1 in both directions of the groove axis.

[0008] Furthermore, a heating element may be advantageous, consisting of a heating resistor as described above and insulators mounted therein.

[0009] It may also be advantageous if the insulator has a cross-sectional shape_L, with only the web_1 having a receiving opening with a cross-sectional shape_A that corresponds to a portion of the cross-sectional shape_L, with the respective insulator being in positive engagement with the receiving opening in both directions with respect to the slot axis. Thus, the insulator is sufficiently firmly connected to the web_1.

[0010] In this case, it can advantageously be provided if the adjacent web_2 has a contact surface with a transverse sectional shape_F in the region of the receiving opening, wherein the insulator has a contact zone with a transverse sectional shape_Z, wherein the cross-sectional shape_Z is different from the cross-sectional shape_F. A different cross-sectional shape_F ensures a load-free relative movement between the web_2 and the insulator.

[0011] For this purpose, it can advantageously be provided if the cross-sectional shape_F has a radius_R and the cross-sectional shape_Z has a radius r, with R > r or R >= 2r. Thus, sufficient freedom of movement of the insulator relative to the web_1 is ensured with respect to the slot axis.

[0012] It can also be advantageous to provide a gap between the contact zone of the insulator and the adjacent web_2. This allows the groove width or gap width to be reduced when the heating resistor is heated until the insulator comes into contact with the web_2. This allows the pressure acting on the insulator or web to be reduced in a direction perpendicular to the groove axis.

[0013] It can be advantageous if the receiving opening has an undercut, whereby a positive connection exists between the insulator and the web_1 in a direction Q perpendicular to the groove axis. A fairly large gap can exist between the insulator and the adjacent web_2 (when cold). This gap may be reduced or increased when the heating element is heated. Regardless of the size of the gap, however, the insulator remains in the web_1. Slipping out of the insulator from the receiving opening in the direction Q perpendicular to the groove axis is thus always prevented. The insulator resting against the web_2 is positively supported with respect to two spatial axes. The free third spatial axis is used to insert the insulator into the receiving opening.

[0014] It may also be advantageous if the receiving opening has a round, oval, polygonal, or angular cross-sectional shape_A and / or if at least the part of the insulator to be received by the receiving opening has a round, oval, polygonal, or angular cross-sectional shape_A. Thus, rotation of the insulator within the receiving opening can also be prevented.

[0015] The insulator is made of a ceramic material or is designed as a metal pin with a ceramic coating. Furthermore, a system can be advantageous, consisting of a heating element as described above and at least part of an exhaust system in the form of an exhaust pipe, with the heating resistor arranged within the exhaust pipe.

[0016] Further advantages and details of the invention are explained in the claims and in the description and shown in the figures.

[0017] They show:

[0018] Figure 1 shows a heating element in perspective view;

[0019] Figure 2a-3c detailed sketches.

[0020] A heating element 10 shown in Figure 1 comprises a heating element in the form of a heating resistor 1. The heating resistor 1 has a plurality of heating loops 1.3, which are formed from two webs 1.2a, 1.2b, or web_1 and web_2 (hereinafter referred to as 1.2a and 1.2b), connected at their ends. Adjacent webs 1.2a, 1.2b are separated from one another by a groove 1.1 with a groove axis 1.1a. In the end region of the groove 1.1, an insulator 2 is provided, which ensures a distance between adjacent heating loops 1, 2a, 1.2b. The heating resistor 1 has a round basic shape_G, which ensures installation in a likewise round exhaust pipe 4.

[0021] The detailed illustrations according to Figures 2a to 3c show the end region of a groove 1.1 between two adjacent webs 1.2a, 1.2b. The two webs 1.2a, 1.2b are separated from one another by the groove 1.1. In the region of the respective groove end, an insulator 2 is provided which is received in the web 1.2a. For this purpose, the web 1.2a has a receiving opening 1.4a with a transverse sectional shape_A which extends transversely to the groove axis 1.1a. The insulator 2 is mounted in the receiving opening 1, 4a. The cross-sectional shape_L of the part of the insulator 2 embedded in the receiving opening 1.4a corresponds to the transverse sectional shape_A. The insulator 2 lies at the level of a contact surface 1.4b of the adjacent web_1. According to the exemplary embodiments 2a to 2d, the contact surface 1, 4b of the web 1.2b or its cross-sectional shape_F is flat in the region of the insulator 2 or in the region or at the level of the adjacent receiving opening 1, 4a. The same applies to the embodiment shown in Fig. 2b.Here, the contact surface 1.4b is also flat, whereby the size of the contact surface is limited to the extent of the groove required for this purpose within the web 1,2b.

[0022] According to the exemplary embodiments in Fig. 2a to 2e, there is almost no gap 3 (in the cold state) or a very small gap 3 between the insulator 2 and the adjacent web 1, 2b. This gap 3 may change when the heating element is heated. However, the insulator 2 is not intended to be firmly seated within the receiving opening 1.4a; the insulator 2 can be moved in a direction Q transverse to the groove axis 1.1. The cross-sectional shape_L of the insulator 2 embedded in the receiving opening 1, 4a corresponds to the cross-sectional shape_A. Given the maximum achievable gap width, it is possible for the insulator 2 to slip out of the receiving opening 1.4a in the direction Q transverse to the groove axis 1.1. However, the insulator 2' rests against the adjacent web 1.2b or the contact surface 1.4b, as sketched in Fig. 2a. Thus, the insulator 2 always remains at least partially in the receiving opening 1.4a.

[0023] According to the exemplary embodiments in Fig. 3a to 3c, the insulator 2 is positively received in the web 1.2a with respect to a direction Q transverse to the groove axis 1.1. For this purpose, the web 1.2a or the receiving opening 1.4a has an undercut 1.5. Thus, a positive connection between the insulator 2 and the web 1, 2a is ensured in both directions relative to the groove axis 1.1a. There is a fairly large gap 3 (in the cold state) between the insulator 2 and the adjacent web 1.2b. This gap 3 may be reduced or enlarged when the heating element is heated. Regardless of the size of the gap 3, however, the insulator 2 remains in the web 1.2a. Slipping out of the insulator 2 from the receiving opening 1.4a in the direction Q transverse to the groove axis 1.1 is thus always prevented.

[0024] According to the embodiment shown in Fig. 2a, 2e, 3a, the embedded part of the insulator 2 has a circular cross-sectional shape_L, with the receiving opening 1.4a having a correspondingly partially circular cross-sectional shape_A. According to Fig. 3a, the receiving opening 1, 4a has a depth t that is greater than a radius r of the round insulator 2, so that said undercut is ensured.

[0025] According to the embodiment shown in Fig. 2c, the embedded part of the insulator 2 has an oval cross-sectional shape_L. The receiving opening 1,4a correspondingly has a partially oval cross-sectional shape_A, so that the insulator 2 can be inserted into the receiving opening 1,4a in a direction normal to the image plane. An undercut of the receiving opening 1,4a is provided here. This is not necessary because the insulator 2 rests against the web 1,2b or its contact surface 1,4b.

[0026] According to the embodiment shown in Figure 3b, the insulator 2 has a trapezoidal cross-sectional shape_L, while according to Figure 3c, the insulator 2 has a truncated cone-shaped cross-sectional shape_L with a round contact zone 2.1 or cross-sectional shape_Z. According to the embodiment shown in Figures 2b, 2d, and 3b, the contact zone 2.1 is flat.

[0027] According to the two exemplary embodiments shown in Fig. 2e and 3c, the contact surface 1, 4b, or its cross-sectional shape F, is round. The radius R of the contact surface 1, 4b is approximately twice as large as the radius r of the contact zone 2.1 of the insulator 2, or as the radius r of the cross-sectional shape Z. Thus, only a minimal form fit in a direction parallel to the groove axis 1.1 results between the contact zone 2.1 of the insulator 2 and the opposite web 1.2b.

[0028] Fig. 3a' shows the embodiment according to Fig. 3a, but without the insulator. The two flanks 1.41, 1.42 of the receiving opening 1.4a can be seen. List of reference symbols

[0029] 1 radiator, heating resistor

[0030] 1.1 Groove

[0031] 1.1 a Groove axis

[0032] 1.2a Bridge_1

[0033] 1.2 b Bridge_2

[0034] 1.3 Heating loop

[0035] 1.4a Receiving opening

[0036] 1.41 flank

[0037] 1.42 flank

[0038] 1.4b Contact surface

[0039] 1.5 Undercut

[0040] 2 Insulator

[0041] 2' insulator

[0042] 2.1 Contact zone

[0043] 3 gap

[0044] 4 exhaust pipe

[0045] 10 Heating element t depth

[0046] Q direction transverse to 1 ,1a

[0047] R Radius r Radius

[0048] Basic form_G of the heating resistor

[0049] Cross-sectional shape_A of receiving opening

[0050] Cross-sectional shape_F of contact surface

[0051] Cross-sectional shape_L of insulator

[0052] Cross-sectional shape_Z of contact zone

Claims

Patent claims Heating resistor (1) for insertion into an exhaust pipe (4), wherein the heating resistor (1) has a basic shape_G in which one or more heating loops (1.3) arranged next to one another are formed, wherein the respective heating loop (1.3) is formed from two webs coupled at the ends, a web_1 (1.2a) and a web_2 (1.2b), wherein adjacent webs (1.2a, 1.2b) delimit a groove (1.1) with a groove axis (1.1a), characterized in that at least one web_1 (1.2a) has a receiving opening (1.4a) with a cross-sectional shape_A for receiving an insulator (2), wherein the adjacent web_2 (1.2b) in the region of the receiving opening (1.4a) a) is flat or b) has a contact surface (1.4b) with a cross-sectional shape_F which is different from the cross-sectional shape_A. Heating resistor (1) according to claim 1, characterized in that the receiving opening (1.4a) has two flanks (1.41, 1.42) which have a longitudinal direction in the direction of the groove axis (1.1a) ensure a positive connection with an insulator (2) to be inserted into the receiving opening (1.4a). Heating element (10) consisting of a heating resistor (1) according to one of the preceding claims and insulators (2) mounted therein. Heating element (10) according to claim 3, characterized in that the insulator (2) has a cross-sectional shape_L, wherein only one web_1 (1, 2a) has a receiving opening (1, 4a) with a cross-sectional shape_A that corresponds to a part of the cross-sectional shape_L, wherein the respective insulator (2) can be brought into a positive connection with the receiving opening (1.4a) in both directions with respect to the groove axis (1.1a). Heating element (10) according to claim 4, characterized in that the adjacent web_2 (1.2b) in the region of the receiving opening (1.4a) has a contact surface (1.4b) with a cross-sectional shape_F, wherein the insulator (2) has a contact zone (2.1) with a cross-sectional shape_Z, wherein the cross-sectional shape_Z is not equal to the cross-sectional shape_F. Heating element (10) according to claim 5, characterized in that the cross-sectional shape_F has a radius_R and the cross-sectional shape_Z has a radius r, with R > r or R >= 2r. Heating element (10) according to one of the preceding claims 3 to 6, characterized in that a gap (3) is provided between the contact zone (2.1) of the insulator (2) and the adjacent web_2 (1.2b). Heating element (10) according to one of the preceding claims 3 to 7, characterized in that the receiving opening (1.4a) has an undercut (1.5), wherein in a direction Q transverse to the groove axis (1.1a) a positive connection exists between the insulator (2) and the web (1.2a). Heating element (10) according to one of the preceding claims 3 to 8, characterized in that the receiving opening (1.4a) has a round, oval, polygonal, or angular cross-sectional shape_A and / or that at least the part of the insulator (2) to be received by the receiving opening (1.4a) has a round, oval, polygonal, or angular cross-sectional shape_A. System consisting of a heating element (10) according to claim 4 and at least part of an exhaust system in the form of an exhaust pipe (4), wherein the heating resistor (1) is arranged within the exhaust pipe (4).

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