JP2002168700A - Temperature sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a temperature sensor, comprising a case having a hole for introducing an exhaust gas, and a resistor for detecting the temperature of exhaust gas introduced into the case through a hole, in which foreign matters, e.g. soot, in the exhaust gas introduced into the case are prevented from adhering to the resistor. SOLUTION: A case 10 has a double structure of first outer cylindrical case 10a and a second cylindrical case 10b, located on the inside of the first case 10a via a gap. Holes 11a and 11b are made, respectively, in the first and second cases, while being shifted in the circumferential direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a case having a hole for introducing a measuring medium, and a temperature-sensitive element which is housed in the case and detects the temperature of the measuring medium introduced from the hole. The present invention relates to a temperature sensor provided.

[0002]

2. Description of the Related Art An example of such a temperature sensor is an exhaust gas temperature sensor for detecting the temperature of exhaust gas in an exhaust pipe of an engine. FIG. 7 shows a conventional general cross-sectional configuration of the exhaust gas temperature sensor. This device has a metal cylindrical case 10 having a hole 11 for introducing a measurement medium on one end side, and a resistor 21 made of platinum or the like as a temperature sensing element, which is housed in the case 10 and mounted therein. And a ceramic substrate 20.

FIG. 3A shows a detailed configuration of the ceramic substrate 20 in FIG. 7, and FIG. 3B shows a plan configuration of FIG. A resistor 21 is formed on the ceramic substrate 20 by printing or the like, and a wiring layer 22 for extracting a signal from the resistor 21 is formed using a platinum paste. The wiring layer 22 further includes a case 10
Lead wire 41 of sheath wiring 40 inserted from the other end side of
Are electrically connected via a metal terminal 30.

The lead wire 41 of the sheath wiring 40 is
Outside the case 10, it is electrically connected to a wiring member 200 for communicating with an external circuit via a terminal 210, and the connection portion is covered and protected by a mold resin 220.

[0005] Such a temperature sensor is screwed to the exhaust pipe via a screw member (nibble) 70 held on the outer periphery of the case 10 so that one end of the case 10 is located within the exhaust pipe with respect to the screw member 70. Be combined.

The exhaust gas in the exhaust pipe is supplied to the case 1
The resistor 21 outputs a signal in accordance with the temperature of the exhaust gas. This signal is output from the wiring layer 2
2, the signal is output from the wiring member 200 to the external circuit via the sheath wiring 40.

[0007]

The hole 11 formed at one end of the case 10 is for introducing a measuring medium in order to improve the responsiveness. However, according to the study by the present inventors, in the above-described conventional exhaust gas temperature sensor, foreign matter (soot or the like) in the exhaust gas (measurement medium) enters through the hole portion 11 and the resistor (temperature-sensitive element) When the resistor 21 is attached, the volume of the resistor 21 increases,
The heat dissipation of the resistor 21 deteriorates, and as a result, the resistor 2
It was found that the characteristics of No. 1 deteriorated.

In view of the above problems, the present invention provides a case having a hole for introducing a measurement medium, and a temperature-sensitive element which is housed in the case and detects the temperature of the measurement medium introduced from the hole. It is an object of the present invention to prevent a foreign substance in a measurement medium introduced into a case from adhering to a temperature-sensitive element in a temperature sensor comprising:

[0009]

In order to achieve the above object, each of the inventions according to the first to fourth aspects of the present invention is directed to a hole (11a, 11b, 11c, 11c) for introducing a measurement medium.
d) a temperature sensor having a case (10) and a temperature sensor (21) housed in the case and detecting the temperature of the measurement medium introduced through the hole, each having the following characteristics: It is.

First, in the temperature sensor according to the first aspect, the case (10) is connected to the outer first case (10).
a) and the first case has a double structure consisting of a second case (10b) located inside the first case via a gap, and both the first and second cases have a double structure. A hole is formed, and a hole (11
a) and the hole (11b) of the second case are shifted from each other.

According to the method, the measuring medium passes through the gap between the first and second cases from the hole (11a) of the first case (10a) and passes through the gap (11b) of the second case (10b). Introduced into element (21). At this time, since the hole of the first case and the hole of the second case are shifted from each other, it is difficult for foreign substances such as soot to reach the temperature-sensitive element. Therefore, it is possible to prevent foreign matter in the measurement medium introduced into the case from attaching to the temperature-sensitive element.

Here, when both the first and second cases have a cylindrical shape, as in the temperature sensor according to the second aspect, the hole (11) of the first case (10a) is formed.
a) and the hole 11b of the second case (10b) can be displaced in the circumferential direction of both cases.

The temperature sensor according to the third aspect is characterized in that the hole (11c) comprises a plurality of holes with a louver in the shape of a door.

According to this, since the opening facing the outside in the hole (11c) is blindfolded from the outside by the louver, it is difficult for foreign substances such as soot to enter the hole. Can be. Therefore, it is possible to prevent foreign matter in the measurement medium introduced into the case from attaching to the temperature-sensitive element.

Further, in the temperature sensor according to the fourth aspect, a mesh-like opening is formed between the hole (11d) and the temperature sensing element (21) in the case (10). Are characterized by interposing a mesh member (13) smaller than the opening area of the hole.

According to this, when the measurement medium is introduced from the hole (11d), foreign substances in the measurement medium are filtered by the mesh member (13). Therefore, it is possible to adopt a configuration in which foreign matter such as soot does not easily enter the hole, and it is possible to prevent foreign matter in the measurement medium introduced into the case from adhering to the temperature-sensitive element.

The reference numerals in parentheses of the above means are examples showing the correspondence with specific means described in the embodiments described later.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. Although not limited, the present embodiment will be described as a case where the temperature sensor of the present invention is embodied as an exhaust gas temperature sensor that detects the temperature of exhaust gas in an exhaust pipe of an engine. In the following embodiments, the same parts are denoted by the same reference numerals in the drawings for simplification of description.

(First Embodiment) FIG. 1 shows a schematic sectional configuration of a temperature sensor according to a first embodiment of the present invention. Also,
FIG. 2 is a sectional view taken along the line AA in FIG. Note that the detailed configuration of the ceramic substrate 20 in FIG. 1 can adopt the same configuration as the temperature sensor shown in FIG. 7, that is, the configuration shown in FIG.

In FIG. 1, reference numeral 10 denotes a cylindrical case which partitions the main body of the temperature sensor, and is made of a heat-resistant metal such as a Ni (nickel) base alloy. A plurality of holes 11 a and 11 b communicating with the inside and outside of the case 10 are formed on one end side (left side in the figure) of the case 10.
Exhaust gas as a measurement medium can be introduced from a and 11b.

Here, the portion (hole forming portion) H where the holes 11a and 11b on one end side of the case 10 are formed is:
An outer first case 10a, and the first case 10a
Has a double structure composed of the second case 10b located inside the first case 10a via a gap. The holes 11a and 11b are formed in the first and second cases 10a and 10b, and the holes 11a of the first case 10a and the holes 11a of the second case 10b are formed.
The position is shifted from b (see FIG. 2).

In this example, as shown in FIG.
Are formed in a cylindrical shape, and the position of the hole 11a of the first case 10a and the position of the hole 11b of the second case 10b in the circumferential direction of the two cases 10a and 10b are changed. It is assumed that it is shifted. The cases 10a and 10b may be displaced in the axial direction.

In the case 10, a rectangular ceramic substrate 20 extending along the longitudinal direction of the case 10 is housed. The ceramic substrate 20 is made of alumina or the like.
A resistor 2 made of a thermistor material such as a platinum-based material as a temperature sensing element for temperature detection
1 is formed by printing or the like. Note that the resistor 21
Is covered with a protective film (not shown) made of glass or the like.

As shown in FIG. 3B, a wiring layer 2 made of platinum paste or the like is formed on one surface of the ceramic substrate 20 so as to face the other end of the case 10 (the right side in the figure).
2 are formed. One end of the wiring layer 22 is electrically connected to the resistor 21, and the other end is connected to the case 1 via a terminal (element terminal) 30 made of a heat-resistant metal such as a Ni alloy.
0 is electrically connected to a lead wire 41 exposed from one end of the sheath wiring 40 inserted from the other end.

The wiring layer 22, the terminal portion 30, and the lead wire 41 are, for example, overlapped with the terminal portion 30 on the wiring layer 22 and laser-welded from the terminal portion 30 side. Can be connected to each other by performing laser welding or caulking and fixing. FIG. 3B shows a fusion part 31 formed by laser welding.

The sheath wiring (seespin) 40 is
Tube (seespin protection tube) 42 that partitions the main body
A lead wire (see-spin lead wire) 41 is disposed inside the tube, and a gap between the lead wire 41 and the tube 42 is filled with an insulating powder such as magnesia to form the tube 4.
2 is formed by holding the lead wire 41 insulated. Note that both the lead wire 41 and the tube 42 are made of, for example, Ni
It can be made of a heat-resistant metal such as a (nickel) -based alloy.

Although not shown in FIG. 1, the sheath wiring 4
On the other end side of 0, as in FIG. 7 described above, a wiring member for communicating with an external circuit is electrically connected to the outside of the case 10 via a terminal. Note that the connection portion may be covered and protected by a mold resin as in FIG.

As shown in FIG. 1, the ceramic substrate 20 is inserted into the case 10, and the ceramic substrate 20 is held by an inner wall of the case 10 by a holding member 50 interposed between the case 10 and the ceramic substrate 20. Is held in. The holding member 50 is made of a wire mesh made of a heat-resistant metal such as a Ni alloy.

The holding member 50 is used for the ceramic substrate 20.
And is arranged so as to contact the inner wall of the case 10. Then, the ceramic substrate 20 is elastically supported by the case 10 by the elastic force of the wire mesh acting so that the holding member 50 itself spreads outward (ie, presses the inner wall of the case 10).

On the other hand, the sheath wiring 40 connected to the wiring layer 22 of the ceramic substrate 20 is connected to the other end of the case 10 via an annular spacer 60 made of a heat-resistant metal such as a Ni alloy. It is fixedly supported. The other end of the case 10 is sealed by the sheath wiring 40 and the spacer 60. Here, the spacer 60
Is fixed to the sheath wiring 40 by caulking and fixed to the case 10 by welding, for example.

In the middle of the outer peripheral surface of the case 10,
A rib 12 protruding from the outer peripheral surface is formed integrally with the case 10, and a screw member (nibble) 70 for attaching a temperature sensor to the exhaust pipe is held on the rib 12. The screw member 70 is made of a metal such as stainless steel, and has a screw that can be screw-coupled to a mounting screw portion (not shown) formed on the exhaust pipe.

Such a temperature sensor can be assembled, for example, as follows. The spacer 60 is caulked and fixed to the sheath wiring 40, and the lead wire 41 of the sheath wiring 40 is fixed.
And the wiring layer 22 of the ceramic substrate 20 are connected via the terminal portion 30.

The holding member 50 may be formed by winding a wire mesh forming the holding member 50 around the outer periphery of the ceramic substrate 20 or forming the wire mesh into a cylindrical shape having a hole through which the ceramic substrate 20 can be inserted. The ceramic substrate 20 is attached to the body by, for example, inserting the ceramic substrate 20 into the body.

The case 10 is formed by pressing the first and second cases 10a and 10b formed by pressing or the like while positioning the holes 11a and 11b of the first case 10 and the second case 10b. Remaining part 10c (see FIG. 1)
Can be formed by welding to the end of the.

Then, the ceramic substrate 20, the terminal portion 3
0, the one in which the sheath wiring 40, the holding member 50, and the spacer 60 are integrated are inserted from the other end side of the case 10,
By welding the spacer 60 and the case 10, the temperature sensor shown in FIG. 1 is completed.

The temperature sensor thus assembled is:
The case 10 is screw-coupled to the exhaust pipe via the screw member 70, and is attached so that one end side of the case 10 is located in the exhaust pipe with respect to the screw member 70. Here, one end side of the case 10 projects from the inner wall of the exhaust pipe into the exhaust pipe,
The exhaust gas flows, for example, from top to bottom in FIG.

The temperature detection is performed as follows. The exhaust gas (measurement medium) in the exhaust pipe is introduced from the holes 11a and 11b of the case 10, and a signal corresponding to the temperature of the exhaust gas is output by the resistor 21. This signal is output from the wiring layer 22 to the outside via the sheath wiring 40.

By the way, according to the present embodiment, the exhaust gas passes through the gap between the first and second cases 10a and 10b from the hole 11a of the first case 10a, and passes from the hole 11b of the second case 10b to the resistor body. (Temperature sensing element) 21. At this time, the hole 11a of the first case and the hole 1 of the second case
1b are shifted from each other, it is necessary for exhaust gas to flow from the hole 11a of the first case to the hole 11b of the second case.

Therefore, foreign substances such as soot contained in the exhaust gas hardly reach the resistor 21. Therefore, according to the first embodiment, it is possible to prevent foreign matter (soot or the like) in the exhaust gas (measurement medium) introduced into the case 10 from adhering to the resistor (temperature-sensitive element) 21. As a result, deterioration of the characteristics of the resistor 21 can be prevented.

(Second Embodiment) The second embodiment is a modification of the first embodiment, except that the configuration of the hole forming portion H at one end of the case 10 is modified. The difference from the embodiment will be described with reference to FIG. FIGS. 4A and 4B are diagrams showing a main part configuration of the present embodiment, in which FIG. 4A is a half sectional view along the sensor axis direction, and FIG.
FIG. 3A is a sectional view taken along line BB of FIG.

A plurality of holes 11c communicating between the inside and the outside of the case 10 are formed in the hole forming portion H at one end of the case 10 of the present embodiment.
Exhaust gas as a measurement medium can be introduced. Here, the hole forming portion H in the case 10 of the present embodiment.
Is a single structure different from the first embodiment. The hole 11c is formed of a plurality of holes with a louver in the shape of a door.

Such a hole forming portion H can be formed by press working or the like. In FIG. 4B, the direction of the louver is inward of the case 10, but as shown in FIG.
The direction of the louver may be outward of the case 10.

According to the second embodiment, since the opening facing the outside in the hole 11c is hidden from the outside by the louver, the exhaust gas (measurement medium)
It is possible to adopt a configuration in which foreign substances such as soot in the inside are hard to enter the hole portion 11c. Therefore, also in the present embodiment, it is possible to prevent foreign matters in the exhaust gas introduced into the case 10 from adhering to the resistor 21, and consequently, the resistor 2
1 can be prevented from deteriorating.

(Third Embodiment) The third embodiment is a modification of the first embodiment, in which the configuration of the hole forming portion H at one end of the case 10 is modified. The difference from the embodiment will be described with reference to FIG. 6A and 6B are diagrams showing a main part configuration of the present embodiment, and FIG. 6A is a schematic cross-sectional view along a sensor axis direction.
(B) is CC sectional drawing of (a).

A plurality of holes 11d communicating between the inside and outside of the case 10 are formed in the hole forming portion H at one end of the case 10 according to the present embodiment.
Exhaust gas as a measurement medium can be introduced.

Here, the hole forming portion H in the case 10 of the present embodiment has a single structure. In the case 10, between the hole 11 d and the resistor (temperature sensing element) 21, a mesh-like opening is formed in each of the holes 11 d.
A mesh member 13 smaller than the opening area of d is provided in a cylindrical shape so as to surround the ceramic substrate 20.
The mesh member 13 can be made of, for example, a metal wire net made of a metal such as a Ni alloy and having excellent heat resistance and corrosion resistance.

That is, in this embodiment, a mesh filter is attached to the opening of the hole 11d for introducing exhaust gas (measurement medium). In addition, the hole forming portion H in the case 10 has a case remaining portion 10c.
And can be formed by welding together with the mesh member 13 to the end of the case remaining portion 10c.

According to the third embodiment, the hole 1
When the exhaust gas (measurement medium) is introduced from 1d, foreign substances (soot and the like) in the exhaust gas are filtered by the mesh member 13. In this way, foreign substances such as soot
d, it is possible to prevent foreign substances in the exhaust gas introduced into the case 10 from adhering to the resistor 21, and as a result, to prevent deterioration of the characteristics of the resistor 21. can do.

(Other Embodiments) When the measurement medium is the exhaust gas of the engine as in the above embodiments, a catalyst for burning the soot in the exhaust gas is provided on the outer peripheral surface of the case 10. May be provided. According to this, by the heat of the exhaust gas, on the outer peripheral surface of the case 10,
Since soot burns, intrusion of soot into the case 10 can be reduced, which is preferable.

As described above, the present invention relates to a temperature control device including a case having a hole for introducing a measurement medium, and a temperature sensing element housed in the case and detecting the temperature of the measurement medium introduced from the hole. In the sensor, in the hole configuration of the case,
The above-described features are provided, and the design of other components can be changed as appropriate.

Further, the present invention provides an exhaust gas temperature sensor,
For example, it can be used as a temperature sensor for measuring the intake air temperature of an engine, the temperature of air inside and outside the room, and the like.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a temperature sensor according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is a diagram showing a detailed configuration of a ceramic substrate.

4A and 4B are diagrams illustrating a main part of a temperature sensor according to a second embodiment of the present invention, wherein FIG. 4A is a half-sectional view along the sensor axis direction, and FIG. FIG.

FIG. 5 is a diagram showing a modification of the second embodiment.

6A and 6B are diagrams illustrating a main part of a temperature sensor according to a third embodiment of the present invention, wherein FIG. 6A is a half-sectional view along the sensor axis direction, and FIG. FIG.

FIG. 7 is a diagram showing a general cross-sectional configuration of a conventional temperature sensor.

[Explanation of symbols]

Reference numeral 10: case, 10a: first case, 10b: second case, 11a: hole of the first case, 11b: hole of the second case, 11c, 11d: hole, 13: mesh member, 21: resistor (temperature-sensitive element).

Claims (4)

[Claims] A hole (11) for introducing a measuring medium.
a, a temperature sensor comprising: a case (10) having a, 11b); and a temperature sensing element (21) housed in the case and detecting the temperature of the measurement medium introduced from the hole. The first case (10a) on the outside has a double structure including a second case (10b) located inside the first case via a gap between the first case (10a) and the first case. The hole is formed in both the first case and the second case, and the hole (11a) of the first case and the hole (11b) of the second case are misaligned. Temperature sensor. 2. The first and second cases (10a, 1a).
0b) are both cylindrical, and the positions of the hole (11a) of the first case and the hole (11b) of the second case are shifted in the circumferential direction of the two cases. The temperature sensor according to claim 1, wherein 3. A hole (11) for introducing a measuring medium.
c) and a temperature sensor (21) housed in the case and detecting the temperature of the measurement medium introduced through the hole, wherein the hole is a door. A temperature sensor comprising a plurality of holes each having a louver. 4. A hole (11) for introducing a measuring medium.
d) and a temperature sensor (21) housed in the case and detecting the temperature of the measurement medium introduced through the hole, wherein the temperature sensor comprises: A temperature sensor characterized in that a mesh member (13) is formed between the hole and the temperature-sensitive element, the mesh being formed in a mesh shape, and each mesh opening is smaller than the opening area of the hole. .