Exhaust sensor with insulating lantern ring

Abstract

An exhaust gas sensor (10) has a sleeve-like housing (12) extending in a longitudinal direction and a ceramic sensor element (14) which is fixed in the housing (12) and projects from the housing (12) in the longitudinal direction on both an exhaust side (20) and a connection side (22), and a protective tube (16) which is fastened to the housing (12) on the exhaust side (20) and which has an opening (161), the sensor element (14) has an opening through which exhaust gas can reach an exhaust-side end region (20) of the sensor element (14), a protective sleeve (18) is mounted on the housing (12) on the connection side (22), which protective sleeve covers a connection-side (22) end region of the sensor element (14), through which protective sleeve (18) an electric wire (30) is guided from the outside to the connection-side end region (22) of the sensor element (14), the protective sleeve (18) is closed on the connection side (22) by an elastic plug (36), in addition, a ceramic insulating collar (34) is received in the protective sleeve (18) on the exhaust side (20) of the spring plug (36), which insulating collar is supported in the longitudinal direction on the exhaust side (20) on an exhaust-side constriction (181) of the protective sleeve (18) and on the connection side (22) on a connection-side constriction (182) of the protective sleeve (18), the insulating collar (34) being supported on the connection side (22) without the entire circumference on the connection-side constriction (182), a plurality of partial peripheries (34.1, 34.2, 34.3, 34.4) spaced apart from each other in the circumferential direction are supported only along the plurality of partial peripheries (34.1, 34.2, 34.3, 34.4).

Description

Technical Field

[0001] An exhaust gas sensor according to the preamble of claim 1 is known from DE 10 2019 215 527 A1. Summary of the Invention

[0002] The insulating collar provided according to the invention has the following functions: electrically insulating the electric wire with respect to the housing or the protective sleeve, mechanically fixing it, and furthermore thermally shielding the connection-side region of the exhaust gas sensor seen from the insulating collar.

[0003] The present invention is based on the desire to reduce the mass of the insulating collar without restricting its function.

[0004] This task is solved by the characterizing features of claim 1, and the dependent claims give further developments of the invention.

[0005] The exhaust gas sensor can be, for example, a lambda sensor.

[0006] The longitudinal direction can be the direction indicated by the particularly straight through-hole of the sleeve-shaped housing.

[0007] In this regard, in the present context, the longitudinal direction is given by the connection of the exhaust side (for example, the exhaust side of the sensor) and the connection side (for example, the connection side of the sensor).

[0008] The constriction of the protective sleeve can be, for example, in a configuration: seen from the insulating collar, the diameter of the protective sleeve decreases at these configurations. The constriction of the protective sleeve can be, for example, a crimp or a rolled portion or the like. Description of the Drawings

[0009] Figure 1 and Figure 2 Embodiments of the present invention are shown by mutually orthogonal cross-sections, Figure 1 wherein is a cross-section along Figure 2 the cutting line I-I in, and Figure 2 is a cross-section along Figure 1 the cutting line II-II in.

[0010] Figure 3 The insulating collar is shown in a plurality of perspective views Figure 1 or Figure 2 of.

[0011] Figure 4 and Figure 5 show other insulating collars according to an alternative of the present invention of the insulating collar shown as Figure 1 , Figure 2 and Figure 3 in.

[0012] Figure 6 andFigure 7 A further alternative to the insulating collar according to the invention is shown. DETAILED DESCRIPTION

[0013] Figure 1 and Figure 2 The figures show mutually orthogonal sectional views of an exhaust gas sensor according to the invention.

[0014] The exhaust gas sensor 10 has a longitudinal direction ( Figure 1 The present invention relates to a sleeve-shaped housing 12 extending horizontally in the embodiment of the present invention, which has an external thread 12.1 for screwing into the exhaust system of an internal combustion engine (for example, a two-wheeled vehicle). A ceramic sensor element 14 is fixed in the through hole 13 of the sleeve-shaped housing 12 by means of an insulating and sealing gasket 15 consisting of, for example, five sub-components.

[0015] The ceramic sensor element 14 is disposed on the exhaust side 20 ( Figure 1 left side) and connection side 22 ( Figure 1 The protective tube 16 is welded to the housing 12 on the exhaust side 20 and has an opening 161 through which the exhaust gas can reach the exhaust side end region 20 of the sensor element 14. The protective sleeve 18 is welded to the housing 12 on the connection side 22 and covers the connection side end region 22 of the sensor element 14. In the present embodiment, four wires 30, 30b are guided from the outside through the protective sleeve 18 to the connection side end region 22 of the sensor element 14. Two of the wires 30, 30b are located Figure 1 within the cutting plane shown in .

[0016] The protective sleeve 18 is closed on the connection side 22 by an elastic plug 36 (for example made of fluororubber (FKM), silicone or a similar material).

[0017] Furthermore, on the exhaust side 20 of the elastic plug 36 a ceramic insulating collar 34 is received in the protective sleeve 18 , the function of which is to electrically insulate and mechanically fix the electrical line 30 relative to the housing 12 or the protective sleeve 18 and also to thermally shield the connection side region 22 of the exhaust gas sensor 10 as viewed from the insulating collar.

[0018] The insulating collar 34 also has the function of isolating tensile loads (e.g., those acting on the connection-side portion 22 of the exhaust gas sensor 10 during handling and assembly) Figure 1 The protective sleeve 18 is led out (from left to right in the figure).

[0019] The insulating collar 34 is supported on the exhaust side 20 on an exhaust side constriction 181 of the protective sleeve 18, which is produced as a conical surface by crimping. The insulating collar 34 is supported on the connection side on a connection side constriction 182 of the protective sleeve 18, which has been produced as a conical surface within the framework of a deep drawing process when producing the protective sleeve 18.

[0020] An insulating collar 34 (also see Figure 3 The connection side 22 is not supported over the entire circumference on the connection side constriction 182 or the exhaust side conical surface of the constriction 182, but only along a plurality of partial circumferences 34.1, 34.2, 34.3 spaced apart from one another in the circumferential direction, which in this embodiment are located at Figure 1 On the exhaust side 20 , in contrast, the insulating collar 34 is supported over the entire circumference on the exhaust-side constriction 181 .

[0021] The insulating collar 34 has a disk-shaped end region 34.5 on the exhaust side, which abuts against the exhaust-side constriction 181 of the protective sleeve 18. More precisely, the exhaust-side outer edge of the disk-shaped end region 34.5 has a chamfer 34.6, with which the insulating collar 34 abuts against the exhaust-side constriction 181 of the protective sleeve 18.

[0022] The insulating collar 34 has a plurality of regions 34a, 34b, 34c which are spaced apart from one another in the circumferential direction, extend in the longitudinal direction and are configured as webs. These regions 34a, 34b, 34c or webs have an outer edge with a chamfer 34.6 on the connection side 22, which abuts against the connection-side constriction 182 of the protective sleeve 18.

[0023] The recess 34 . 7 (starting from the cylindrical part) is located between these regions or webs.

[0024] The insulating collar 34 has a through hole 34.8 in the longitudinal direction for receiving the electric wire 30. The through hole 34.8 is located radially inside the recess 34.7.

[0025] As shown in the figures, the disk-shaped end region 34.5 can have a disk-shaped recessed region 1 which is surrounded by an annular border 2, wherein the through-hole 34.8 opens into the disk-shaped recessed region, wherein the annular border extends in the axial direction on the exhaust side beyond the recessed region 1. This is advantageous because a more stable fastening can be achieved by means of the recessed region.

[0026] It is conceivable that the regions 34a, 34b, 34c, 34d extending in the longitudinal direction respectively have a first partial region 3 extending in the axial direction away from the disc-shaped end region 34.5 and respectively have a second partial region 4 extending in the axial direction facing the disc-shaped end region 34.5, wherein the first partial region 3 tapers in the radial direction with respect to the second partial region 4. Accordingly, the first partial region is radially retracted inwardly with respect to the second partial region. In other words, the regions 34a, 34b, 34c, 34d extending in the longitudinal direction respectively have a first partial region 3 extending in the axial direction away from the disc-shaped end region 34.5 and respectively have a second partial region 4 extending in the axial direction facing the disc-shaped end region 34.5, wherein the disc-shaped end region 34.5 protrudes in the radial direction beyond the first partial region 3. Thereby, it is possible to reduce the material required for manufacturing. This is advantageous because thereby the total weight of the exhaust gas sensor can be reduced, so that the exhaust gas sensor can be fastened more stably and simply in the exhaust system.

[0027] If the disc-shaped end region 34.5 does not have the disc-shaped recessed region 1, an "axial gate mark" is generally provided. The "gate mark" is used to center the components and prevent the components from being overly twisted relative to each other to prevent damage to the pipelines passing through these parts. If the disc-shaped end region 34.5 has the disc-shaped recessed region 1, there is no longer sufficient space for the "axial gate mark". In this case, it is conceivable to provide a "radial gate mark" instead of the "axial gate mark". Here, the regions 34a, 34b, 34c, 34d extending in the longitudinal direction are constructed wider in the circumferential direction in the embodiment having the disc-shaped recessed region than in the embodiment without the disc-shaped recessed region 1.

[0028] As shown in the drawings, the second partial region 4 may have a ramp, and the disc-shaped end region 34.5 and the first partial region 3 are connected to each other in the axial direction through this ramp. A more stable fastening can be achieved through this ramp, for example, a form-fitting fastening.

[0029] In the present embodiment, it is provided that the electric wires 30 respectively have contact springs 30a (see Figure 1 ), the contact springs are pressed against the contact surface 14a of the ceramic sensor element 14 on the exhaust side and have a bent region on the connection side, the bent region fixing the exhaust-side end of the cable 30b, wherein the bent region is received in the through hole 34.8 of the insulating collar 34.

[0030] The exemplary insulating collar 34 is made of aluminum oxide and manufactured by means of CIM (ceramic injection molding). This results in a very smooth surface and rounding or chamfering of the edges of the insulating collar, or completely eliminates the sharp-edged transition. Thus, damage to the cable 30b, in particular the plastic sheath of the cable 30b, when inserted into the through-hole 34.8 can always be reliably excluded.

[0031] Figure 4 and Figure 5 show other insulating collars 34, which are Figure 3 alternative solutions according to the invention of the insulating collar 34 shown in []. They differ in terms of size and the number of tabs. In all embodiments, the weight saving compared to a cylindrical part of the same length and the same maximum diameter is at least 29%.

[0032] Advantageously, the injection molding is not carried out axially as usual, but radially. This can be achieved by a new advantageous design (see Figure 6 , 34a, 34b, 34c, 34d) and simplifies the manufacturing process and the arrangement in the tool.

[0033] Compared with the traditional design, Figure 6 and Figure 7 the embodiments shown in [] enable maximum weight saving.

Claims

1. An exhaust gas sensor (10) having a sleeve-shaped housing (12) extending in a longitudinal direction and a ceramic sensor element (14) which is fixed in the housing (12) and projects out of the housing (12) on the exhaust gas side (20) and on the connection side (22) in the longitudinal direction, wherein, The protective tube (16) is fastened to the housing (12) on the exhaust side (20). The protective tube has an opening (161) through which the exhaust can reach the exhaust-side end region (20) of the sensor element (14). A protective sleeve (18) is assembled to the housing (12) on the connection side (22), and the protective sleeve covers the connection-side (22) end region of the sensor element (14). A wire (30) is guided from the outside through the protective sleeve (18) to the connection-side end region (22) of the sensor element (14). The protective sleeve (18) is closed on the connection side (22) by an elastic plug (36). A ceramic insulating collar (34) is received in the protective sleeve (18) on the exhaust side (20) of the elastic plug (36). The insulating collar is supported in the longitudinal direction on the exhaust-side constriction (181) of the protective sleeve (18) on the exhaust side (20) and on the connection-side constriction (182) of the protective sleeve (18) on the connection side (22). It is characterized in that the insulating collar (34) is supported on the connection-side constriction (182) not over its entire circumference, but only along a plurality of partial circumferences (34.1, 34.2, 34.3, 34.4) that are spaced apart from each other in the circumferential direction.

2. The exhaust gas sensor according to claim 1, wherein, The insulating collar (34) is supported on the exhaust-side constriction (181) over its entire circumference on the exhaust side (20).

3. The exhaust gas sensor according to claim 1 or 2, wherein, The insulating collar (34) has a disc-shaped end region (34.5) on the exhaust side, and the disc-shaped end region abuts against the exhaust-side constriction (181) of the protective sleeve (18).

4. The exhaust gas sensor according to claim 3, wherein, The disc-shaped end region (34.5) extends in the longitudinal direction by no more than 50% of the longitudinal extension of the insulating collar (34).

5. The exhaust gas sensor according to claim 3 or 4, wherein, The outer edge of the disc-shaped end region (34.5) on the exhaust side has a chamfer (34.6), and the insulating collar (34) abuts against the exhaust-side constriction (181) of the protective sleeve (18) with the chamfer.

6. The exhaust gas sensor according to any one of claims 1 to 5, wherein, The insulating collar (34) has a plurality of regions (34a, 34b, 34c, 34d), in particular tabs, that are spaced apart from each other in the circumferential direction and extend in the longitudinal direction, and the regions abut against the connection-side constriction (182) of the protective sleeve (18).

7. The exhaust gas sensor according to claim 6, wherein, The outer edges of the connection sides of the regions (34a, 34b, 34c, 34d) each have a chamfer (34.6), and the insulating collar (34) abuts against the connection-side constriction (182) of the protective sleeve (18) with the chamfer.

8. The exhaust gas sensor according to claim 6 or 7, wherein, The insulating collar (34) has recesses (34.7) between the regions (34a, 34b, 34c, 34d) starting from a substantially cylindrical part.

9. The exhaust gas sensor according to any one of the preceding claims, wherein, The insulating collar (34) has a through-hole (34.8) in the longitudinal direction for receiving the wire (30).

10. The exhaust gas sensor according to any one of the preceding claims, wherein, The disc-shaped end region (34.5) has a disc-shaped recessed region (1) surrounded by an annular boundary (2), wherein the through hole (34.8) opens into the disc-shaped recessed region, and wherein the annular boundary extends axially beyond the recessed region (1) on the exhaust side.

11. The exhaust gas sensor according to any one of the preceding claims, wherein, The regions (34a, 34b, 34c, 34d) extending in the longitudinal direction each have a first partial region (3) facing away from the disc-shaped end region (34.5) in the axial direction and each have a second partial region (4) facing the disc-shaped end region (34.5) in the axial direction, wherein the first partial region (3) tapers in the radial direction with respect to the second partial region (4).

12. The exhaust gas sensor according to any one of the preceding claims, wherein, The second partial region (4) has a ramp, and the disc-shaped end region (34.5) and the first partial region (3) are connected to each other in the axial direction by means of the ramp.

13. The exhaust gas sensor according to claim 9, wherein, The electric wires (30) each have a contact spring (30a) which is pressed against the contact surface (14a) of the ceramic sensor element (14) on the exhaust side and has a bent region on the connection side which fixes the exhaust-side end of the cable (30b), wherein the bent region is received in the through hole (34.8) of the insulating collar (34).

14. The exhaust gas sensor according to claim 8 and additionally according to claim 9 or claim 10, wherein, The through hole (34.8) is arranged radially inside the recess (34.7).

15. The exhaust gas sensor according to any one of the preceding claims, wherein, The insulating collar (34) is made of alumina.

16. The exhaust gas sensor according to any one of the preceding claims, wherein, The insulating collar (34) is manufactured by means of CIM (ceramic injection moulding).

17. An exhaust system for an internal combustion engine of a two-wheeler, having an exhaust gas sensor (10) according to any one of the preceding claims.

18. A two-wheeler having an internal combustion engine, having an exhaust system according to the previous claim.

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