High temperature sensor with a moulded protective tube

Abstract

The invention relates to a method for producing a high temperature sensor, in particular a high temperature sensor for measuring the exhaust gas temperature of motor vehicles, comprising a sensor element and a protective tube which at least partially surrounds the sensor element. Said protective tube is closed on the hot side of the high temperature sensor by a shaping method, in particular molding.

Claims

1. A method for producing a high-temperature sensor (10) for measuring the exhaust gas temperature of motor vehicles, comprising a sensor element (2) and a protective tube (5) surrounding the sensor element (2) at least partially, wherein the protective tube (5) is closed on a hot side of the high-temperature sensor (10) by a pressing process and the protective tube (5) is pressed such that the protective tube (5) has two tip-shaped sections (11a) after the pressing, and wherein the two tip-shaped sections (11a) are thin tips projecting axially from a pressing section (11) and together defining a constricted region (11b) therebetween.

2. The method according to claim 1, characterized in that the pressing process is carried out, at least partially, elastically.

3. The method according to claim 2, characterized in that the the protective tube (5) is pressed such that the protective tube (5) has two tip-shaped sections (11a; 11b) after the pressing.

4. The method according to claim 2, characterized in that the pressing process realizes a compaction of a material arranged in the protective tube.

5. The method according to claim 1, characterized in that the pressing process is a pressing process and in that the protective tube (5) is pressed radially homogeneously.

6. The method according to claim 5, characterized in that the pressing process realizes a compaction of a material arranged in the protective tube.

7. The method according to claim 1, characterized in that the protective tube (5) is welded after the pressing process.

8. The method according to claim 7, characterized in that the pressing process realizes a compaction of a material arranged in the protective tube.

9. The method according to claim 1, characterized in that the pressing process realizes a compaction of a material arranged in the protective tube.

10. The method according to claim 1, characterized in that the sensor element (2) is not in contact with the protective tube (5).

11. The method according to claim 1, characterized in that a filling material (9b) containing boron nitride particles, is arranged in the protective tube (5) around the measuring section (3) of the sensor element prior to the pressing process.

12. The method according to claim 1, characterized in that the protective tube (5) is thermally conditioned during at least one of prior to, during, and after the pressing process.

13. The method according to claim 12, characterized in that the thermal conditioning is carried out by means of at least one of laser light, microwave radiation, and inductive heating.

14. The method according to claim 12, characterized in that the thermal conditioning is carried out by means of ultrasonic energy.

15. The method according to claim 12, characterized in that prior to and/or during the pressing process an electric current flows through the protective tube (5) and the thermal conditioning is realized by electrical resistance heating.

16. A high-temperature sensor (10), for measuring the exhaust gas temperature of motor vehicles, comprising: a sensor element (2); and a protective tube (5) surrounding the sensor element (2) at least partially, wherein the protective tube (5) is closed on a hot side of the high-temperature sensor by a pressing process, and the protective tube (5) is pressed such that the protective tube (5) has two tip-shaped sections (11a) after the pressing, and wherein the two tip-shaped sections (11a) are thin tips projecting axially from a pressing section (11) and together defining a constricted region (11b) therebetween.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1a shows a lateral view of a first high-temperature sensor;

(3) FIG. 1b shows a cross-sectional view of the high-temperature sensor of FIG. 1a;

(4) FIG. 1c shows a detailed view of region B of FIG. 1b;

(5) FIG. 2a shows a lateral view of a second high-temperature sensor;

(6) FIG. 2b shows a cross-sectional view of the high-temperature sensor of FIG. 2a;

(7) FIG. 2c shows a detailed view of region B of FIG. 2a; and

(8) FIG. 2d shows a detailed view of region C of FIG. 2b.

DETAILED DESCRIPTION

(9) FIG. 1a shows a high-temperature sensor 10 whose protective tube 5 was pressed radially homogeneously in a pressing section 11. The protective tube thus has a reduced diameter in pressing section 11. The tip of the high-temperature sensor 10 has, in this case, a flat design.

(10) FIG. 1b shows a cross-sectional view of the high-temperature sensor 10 of FIG. 1a. The cutting plane extends along the sensor element 2. Electrical connections 2a; 2b are located at the cold end of the high-temperature sensor 10, the pressing section 11 is located at the hot end.

(11) FIG. 1c shows a detailed view of region B of FIG. 1b. In particular, it can be seen that the sensor element 2 and the measuring section 3 thereof are not in contact with the protective tube 5, not even in the pressing section 11 in which the protective tube 5 has a reduced diameter.

(12) During the pressing of the protective tube 5 the material 9b arranged around the measuring section 3 and having good heat-conducting properties was compacted, respectively, compressed in the pressing section 11, so that the heat conduction from the outside of the high-temperature sensor to the measuring section 3 is improved.

(13) In the axial section of the protective tube 5, outside the pressing section 11, a filling material 9a is provided around the sensor element 2, which is different from the filling material 9b having good heat-conducting properties.

(14) Another exemplary embodiment of a high-temperature sensor 10 according to the invention is shown in FIGS. 2a to 2d. The configuration thereof is substantially comparable with that of the high-temperature sensor shown in FIGS. 1a to 1c. In this embodiment the pressing is not carried out homogeneously radially, however, but inside the cutting plane illustrated in FIG. 2b. Thus, the reduction of the diameter of protective tube 5 in pressing section 11 is not uniform, but a laterally shaped contour of the pressing section 11 with two tips 11a and a constricted region 11b is formed. The thin tips made of the material of the protective tube, with good heat-conducting properties, allow a particularly good heat transfer to the measuring section 3.