JPH08128900A - Liquid temperature sensor and mounting device therefor - Google Patents

Abstract

PURPOSE: To prevent deterioration and life shortening of a thermistor due to liquid entered. CONSTITUTION: In a liquid temperature sensor, the tip of a metal tube 1 is closed, a thermistor 2 is inserted in the tip of the tube 1, the thermistor 2 is connected to a terminal 4 through a lead wire 3, and the open base of the tube 1 and terminal 4 are embedded in a body 7 of synthetic resin. A flange 20 is formed in the base of the tube 1, having a number of jogs 21 and 21' on the surfaces on both sides.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid temperature sensor for measuring the temperature of liquid such as cooling water of a water-cooled engine and a mounting device for the same.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional liquid temperature sensor and its mounting device (for example, see Japanese Utility Model Laid-Open No. 58-72635).
The cylindrical tube 41 made of synthetic resin is closed at its tip (bottom end in FIG. 3) to be airtight, and its base end (FIG. 3).
The upper end is opened with a larger radius. A thermistor 2, which is a semiconductor heat sensitive element, is inserted so as to contact the tip of the tube 41, two lead wires 3 are drawn out from the thermistor 2, and the lead wire 3 is covered for insulation. . The base ends of the two lead wires 3 are tubes.
It is in the opening of 41 and is connected to the two rod-shaped terminals 4 by soldering or the like. The vicinity of the opening on the outer periphery of the tube 41 is fitted into the central hole 43 of the plate-shaped metal mounting member 42, and the synthetic resin connector 5 is provided at the open end of the tube 41 and the large diameter portion of the central hole 43 of the mounting member 42. It is fixed by outsert molding. The open end of the tube 41 is hermetically closed by the connector 5, and the terminal 4 is fixed to the connector 5. A plurality of screw insertion holes 44 are formed in the mounting member 42.

For example, an insertion hole 14 is formed in a water outlet (wall) 13 of a cooling water container (attached member) 8 of a water-cooled engine, a tube 41 is inserted in the insertion hole 14, and a mounting member is attached.
42 abuts the outer surface 19 of the water outlet 13. The screw 45 is inserted into the insertion hole 10 and screwed into the screw hole 46 of the water outlet 13, and the liquid temperature sensor is attached to the cooling water container 8. An annular O-ring groove 17 is formed in the flange surface 15 of the mounting member 42 facing the water outlet 13 and surrounding the tube 41, and an O-ring 18 is mounted in the O-ring groove 17. The tip of the tube 41 located inside the water outlet 13 and the like come into contact with the cooling water, and the leakage of the cooling water from the space between the insertion hole 14 and the outer peripheral surface of the tube 41 to the outside of the O-ring 18 is caused by the O-ring groove. Bottom of 17 (top in Figure 3)
It is prevented by sealing between the outer surface 19 and the outer surface 19 of the water outlet 13. The temperature of the cooling water is transmitted to the thermistor 2 via the tip of the tube 41, and the measurement output by the thermistor 2 is transmitted to the outside through the lead wire 3 and the terminal 4.

In the liquid temperature sensor of FIG.
There is a considerable difference in coefficient of thermal expansion between the synthetic resin portion of the connector 5 and the metal portion of the mounting member 42, and the temperature of the cooling water changes considerably. In the conventional liquid temperature sensor, if such a state continues, a minute gap (gap, crack) is generated in the tube 41 / connector 5 portion contacting the inner surface of the mounting member 42. This gap opens on the surface of the connector 5 in the vicinity of the contact portion with the mounting member 42, and on the surface of the tube 41 in the O-ring groove 17
The opening will be formed in the portion adjacent to. Then, pressure acts on the cooling water container 8 to allow the cooling water to pass through the insertion hole 14 and the tube.
Through the outer surface of the tube 41, between the inner surface of the O-ring 18 and the outer surface of the tube 41, and further along the gap between the surface of the tube 41 and the central hole 43 of the mounting member 42, It penetrates into the contact portion between the surface of the tube 41 and the lower end of the connector 5. In addition, the water in the engine room above the cooling water container 8 comes into contact with the inner surface of the mounting member 42 through the opening on the surface of the connector 5 near the contact portion with the mounting member 42, and the minute portion of the connector 5 that contacts the inner surface of the mounting member 42. It penetrates into the contact portion between the surface of the tube 41 and the lower end of the connector 5 through the gap. Tube 41
Since there is also a minute gap between the connector 5 and the connector 5, the cooling water and the water from the engine room reach the thermistor 2 through the gap and the tube 41 and the lead wire 3.

[0005]

In the conventional liquid temperature sensor and its mounting device, the infiltration of cooling water or the like causes deterioration due to corrosion of the thermistor, which lowers the durability of the liquid temperature sensor and shortens its service life. To do. SUMMARY OF THE INVENTION It is an object of the present invention to prevent deterioration of a thermistor and shortening of its life due to infiltration of liquid in a liquid temperature sensor and its mounting device.

[0006]

According to the present invention, the tip of the metal tube (1) is closed, the thermistor (2) is inserted into the tip of the tube (1), and the thermistor (2) is connected to the lead wire (3). )
In the liquid temperature sensor, the tube (1) is connected to the terminal (4) through the open base end of the tube (1) and the terminal (4) embedded in the synthetic resin body (7) and connected. The flange portion (20) is formed at the base end portion of the, and a large number of uneven portions are formed on both surfaces of the flange portion (20). And, the flange portion (20) at the base end portion is wide and can be formed substantially perpendicular to the axis of the tube (1), and substantially concentric convex portions and concave portions are formed on both surfaces of the flange portion (20). Rippled concavo-convex parts (21), (2
1 ') can be formed and the body (7) has a flange (6)
Are integrally formed, and the flange (6) has multiple through holes.
(10) can be formed, and a metal reinforcing ring (11) can be fitted into each insertion hole. Further, according to the present invention, the tip of the metal tube (1) of the liquid temperature sensor is closed, the thermistor (2) is inserted into the tip of the tube (1), and the open base end of the tube (1) is removed. In the mounting device of the liquid temperature sensor, which is embedded in the synthetic resin body (7) and is joined, and the tube (1) of the liquid temperature sensor is inserted into the insertion hole (14) of the mounted member (8), A tapered part (29) is formed in the outer opening of (14), and it is between the tapered part (29) of the insertion hole (14), the outer peripheral surface of the tube (1) and the flange surface (15) of the body (7). Is an O-ring
It is configured to be sealed by (18). The annular groove surrounded by the tapered portion (29) of the insertion hole (14), the outer peripheral surface of the tube (1), and the flange surface (15) of the body (7) has a substantially triangular cross section. A ring can be attached, and a wide flange (20) is formed at the base end of the tube (1) and is substantially perpendicular to the axis of the tube (1). Rippled concavo-convex portions (21) and (21 ') in which concentric convex portions and concave portions are alternately arranged in sequence can be formed.

[0007]

[Function] The tip of the metal tube (1) is closed, the thermistor (2) is inserted into the tip of the tube (1), the liquid temperature is measured by the thermistor (2), and the measurement output is taken out from the liquid temperature sensor. Be done. The open base end of the tube (1) is embedded and connected to the synthetic resin body (7), and the tube (1) of the liquid temperature sensor is inserted into the insertion hole (14) of the mounted member, Temperature is transmitted to the thermistor (2) through the tip of the tube (1). Since the flange (20) was formed on the base end of the tube (1) and many irregularities were formed on both sides of the flange (20), the surface area of the flange (20) of the tube (1) was large. Therefore, the distance from the tubular portion on the surface of the tube (1) to the tubular portion on the inner surface becomes long. A taper part (29) is formed in the outer opening of the insertion hole (14) to connect the taper part (29) of the insertion hole (14), the outer peripheral surface of the tube (1) and the flange surface (15) of the liquid temperature sensor. The space is sealed by the O-ring (18), and the liquid can be prevented from leaking and entering.

[0008]

1 (a) and 1 (b) show a first embodiment of a liquid temperature sensor and its mounting device according to the present invention. In the description of the first embodiment of FIGS. 1 (a) and 1 (b), the same components as those of the conventional example of FIG. 3 are designated by the same reference numerals and the description thereof will be omitted in principle. In the first embodiment of the present invention, the tube 1 is formed by deep drawing a stainless steel plate material, and the tube 1 has a large diameter portion 25 and an outer step portion 22 (a portion substantially perpendicular to the axis of the tube 1). ), Medium diameter part 26, gentle step part 2
3, the small diameter portion 27 is formed continuously. When the tube 1 is joined to the body 7, the outer step portion 22 is located at a portion slightly away from the flange surface 15 of the body 7, and the thermistor 2 is inserted into the closed tip of the small diameter portion 27. The tube 1 becomes a large-diameter portion 25 from the outer step portion 22 toward the base end, and a wide flange portion 20 that is substantially perpendicular to the axis of the tube 1 is formed at the base end portion, as shown in FIG. 1 (b). As described above, the concavo-convex portion 21 in which substantially concentric convex portions and concave portions are alternately arranged on both surfaces of the flange portion 20,
21 'is formed. The synthetic resin in the tube 1 is integral with the body 7 including the connector 5 and the flange 6, and when the body 7 is molded, half of the large diameter portion 25 of the tube 1, the thermistor 2, the lead wire 3, the insert of the terminal 4, etc. Are embedded and combined. In addition, in the liquid temperature sensor of the first embodiment of the present invention, a minute gap (gap, crack) is formed between the inner and outer surfaces of the stainless steel tube 1 and the synthetic resin body 7 that comes into contact therewith, and The gap is the surface of the flange surface 15 and opens near the tube 1. A plurality of insertion holes 10 are formed in the flange 6, and a reinforcing ring (color) 11 made of metal is fitted into the insertion holes 10 by insert molding if desired to secure the strength of the mounting portion.

The water outlet 13 of the cooling water container (attached member) 8 has a through hole 14 having a large diameter portion 30 in order from the outer surface.
Step portion 33 (a portion substantially perpendicular to the center line of the insertion hole 14),
The middle-diameter portion 31 is continuously formed, and the step portion 33 is located at a position about half the depth of the insertion hole 14. The O-ring 18 is fitted to the tip of the tube 1 and then moved toward the base end of the tube 1 to bring the O-ring 18 into contact with the outer step 22 of the tube 1 to prepare for mounting the liquid temperature sensor. . When the liquid temperature sensor is attached to the cooling water container 8, the tube 1 is inserted from the tip into the insertion hole 14 of the water outlet 13. The flange surface 15 of the liquid temperature sensor abuts the outer surface 19 of the water outlet 13 at the mounting position shown in FIG. In the state shown in FIG. 1 (a), the outer O-ring mounting groove 34 is formed by the outer surface 22 of the tube 1 and the outer surface of the medium diameter portion 26 and the surface 33 of the water outlet 13 and the inner surface of the large diameter portion 30.
Is configured. The outer surface of the O-ring 18 mounted in the O-ring mounting groove 34 is in close contact with the outer surface of the outer stepped portion 22 and the middle diameter portion 26 of the tube 1 and the inner surface of the large diameter portion 30 of the water outlet 13. ing.

The tip of the tube 1 located inside the water outlet 13, the small diameter portion 27, the step portion 23 and a part of the middle diameter portion 26 are in contact with the cooling water 38. Regarding the cooling water which is about to leak from the inner surface of the middle diameter portion 31 of the insertion hole 14 and the outer surface of the middle diameter portion 26 of the tube 1, the O ring 18 has an inner peripheral surface of the O ring mounting groove 34 (of the tube 1). Outer surface of medium diameter part 26) / Outer step 22
This is prevented by sealing between the outer peripheral surface (the large diameter portion 30 of the water outlet 13) and the outer peripheral surface. Even when the O-ring 18 is separated from the outer step portion 22 of the tube 1, the cooling water is prevented by the O-ring 18 sealing the inner peripheral surface and the outer peripheral surface of the O-ring mounting groove 34. It The sealing not only prevents the cooling water from leaking to the outside of the cooling water container 8, but also allows the cooling water to enter the inside of the liquid temperature sensor, that is, the surface of the flange surface 15 and the tube 1.
It is also prevented that the cooling water enters from the gap that opens in the vicinity of the above, and that the cooling water passes through the inside of the tube 1 and enters the thermistor 2.

FIG. 2 shows a second embodiment of the liquid temperature sensor and its mounting device of the present invention. In the description of the second embodiment of FIG. 2, the same components as those of the first embodiment of FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted in principle. In the first embodiment of the present invention, the large diameter portion 25 and the outer step portion 22 are formed in the tube 1, and the large diameter portion 30 and the step portion 33 are formed in the insertion hole 14, but in the second embodiment, the large diameter portion 25 is formed.・ Outer step 22,
The large-diameter portion 30 and the step portion 33 are omitted, and instead, the tapered portion 29 is cut out at the outer opening of the insertion hole 14. In the insertion hole 14 of the water outlet 13 of the cooling water container 8, a taper portion 29 is formed at the outer opening, and then a medium diameter portion 31 is continuously formed. The tube 1 has a medium-diameter portion 26, a gentle step portion 23, and a small-diameter portion 27 that are continuously formed. The medium-diameter portion 26 has a wide flange portion 20 formed at the base end thereof.
The structure of 20 is the same as that of the first embodiment.

Fit the O-ring 18 to the tip of the tube 1,
Next, the tube 1 is moved in the proximal direction, the O-ring 18 is brought into contact with the flange surface 15 of the flange 6, and the mounting of the liquid temperature sensor is prepared. Liquid temperature sensor for cooling water container 8
When the tube 1 is attached to the water outlet 13, the tube 1 is inserted through the insertion hole 14 of the water outlet 13 so that the flange surface 15 of the body 7 of the liquid temperature sensor abuts the outer surface 19 of the water outlet 13 at the attachment position shown in FIG. In the state shown in FIG. 2, the outer surface of the medium diameter portion 26 of the tube 1, the taper portion 29 of the water outlet 13 and the flange surface 15 of the flange 6 of the body 7 constitute an annular groove 36 having an annular and substantially triangular cross section. . The outer surface of the O-ring 18 mounted in the annular groove 36 in a compressed state is in close contact with the outer surface of the medium diameter portion 26 of the tube 1, the taper 29 of the water outlet 13 and the flange surface 15 of the flange 6. are doing.

In the liquid temperature sensors of the first and second embodiments, the wide flange portion is provided at the base end portion of the tube 1.
20 is formed, and the concavo-convex portions 21 and 2 in which substantially concentric convex portions and concave portions are alternately arranged in sequence on both surfaces of the flange portion 20.
1'is formed. Therefore, the flange portion 20 of the tube 1
Surface area of the tube 1 increases, the distance from the cylindrical portion on the surface of the tube 1 to the cylindrical portion on the inner surface increases, the infiltration route of the liquid along the surface of the tube 1 increases, and the time for the liquid to reach the thermistor 2 increases. Becomes longer. Further, since the connector 5 and the flange 6 are integrally formed, there is no gap (water gap between the metal and the synthetic resin in FIG. 3) into which water in the engine room should enter, so that the engine room Water cannot enter the surface of the liquid temperature sensor.

In the liquid temperature sensor mounting device of the second embodiment, the fact that the cooling water in the cooling water container 8 tends to leak between the inner surface of the insertion hole 14 and the outer peripheral surface of the tube 1, It can be prevented by an O-ring 18 that seals between the tapered portion 29 of the insertion hole 14 and the outer peripheral surface of the tube 1.
Also, the water in the engine room is the flange surface of the liquid temperature sensor.
The O-ring 18 that seals between the taper portion 29 of the insertion hole 14 and the flange surface 15 of the liquid temperature sensor prevents an attempt to penetrate through between the cooling water container 8 and the outer surface 19 of the cooling water container 8. You can

[0015]

In the liquid temperature sensor of the present invention, the open base end of the tube and the terminal are embedded and joined in the body made of synthetic resin, and the flange is formed at the base end of the tube. A large number of concave and convex portions are formed on both surfaces of the. Therefore, the surface area of the flange portion of the tube becomes large, the infiltration route of the liquid along the outer surface of the tube becomes long, and the time for the liquid to reach the thermistor becomes long. In addition, since the connector and the flange are integrally formed, and there is no gap (the gap between the metal and the synthetic resin in the conventional example) in which water in the engine room should enter on the surface of the liquid temperature sensor, Water cannot enter the surface of the liquid temperature sensor. Further, in the liquid temperature sensor mounting device of the present invention, a taper portion is formed at the outer opening of the insertion hole of the mounted member, and the space between the taper portion of the insertion hole, the outer peripheral surface of the tube and the flange surface of the body is O. It is sealed by a ring. Therefore, when the liquid (for example, cooling water) in the mounted member tries to penetrate or leak between the inner surface of the insertion hole and the outer peripheral surface of the tube, the tapered portion of the insertion hole and the outer peripheral surface of the tube are prevented. This can be prevented by an O-ring that seals the space between the mounted members, and liquid outside the mounted member (for example, water in the engine room) will penetrate between the flange surface of the body of the liquid temperature sensor and the outer surface of the mounted member. This can be prevented by an O-ring that seals between the tapered portion of the insertion hole and the flange surface of the body of the liquid temperature sensor. As described above, the liquid temperature sensor itself has a structure for delaying the infiltration of the liquid, and the mounting device of the liquid temperature sensor is provided with the O-ring for preventing the infiltration of two kinds of liquids, so that the thermistor is deteriorated due to the infiltration of the liquid. Also, it is possible to prevent shortening of life.

[Brief description of drawings]

FIG. 1 (a) is a sectional view of a first embodiment.
(b) is a partially enlarged view of FIG. 1.

FIG. 2 is a sectional view of a second embodiment.

FIG. 3 is a cross-sectional view of a conventional liquid temperature sensor and its mounting device.

[Explanation of symbols]

 1 Tube 2 Thermistor 3 Lead wire 4 Terminal 6 Flange 7 Body 8 Cooling water container 10 Insertion hole 14 Insertion hole 15 Flange surface 18 O-ring 20 Flange portion 21 Rippled uneven portion 21 'Rippled uneven portion 22 Outside step 29 Tapered portion

Claims (7)

[Claims] 1. A body made of a synthetic resin, wherein the tip of a metal tube is closed, a thermistor is inserted into the tip of the tube, the thermistor is connected to a terminal through a lead wire, and the base end portion of the tube and the terminal are open. A liquid temperature sensor having a flange portion formed at a base end portion of a tube and a large number of concave and convex portions formed on both surfaces of the flange portion in a liquid temperature sensor embedded in and joined to a liquid temperature sensor. 2. The liquid temperature sensor according to claim 1, wherein the flange portion of the base end portion is wide and is formed substantially perpendicular to the axis of the tube. 3. The liquid temperature sensor according to claim 1, wherein a ripple-shaped concavo-convex portion in which substantially concentric convex portions and concave portions are alternately arranged is formed on both surfaces of the flange portion. 4. The liquid temperature according to claim 1, wherein a flange is integrally formed on the body, a plurality of insertion holes are formed in the flange, and a metal reinforcing ring is fitted in each insertion hole. Sensor. 5. The liquid temperature sensor has a metal tube with a closed tip, a thermistor inserted into the tip of the tube, and an open base end of the tube embedded in a synthetic resin body to be bonded to the body. In a liquid temperature sensor mounting device in which a tube of a liquid temperature sensor is inserted through an insertion hole of a mounting member, a taper portion is formed at an outer opening of the insertion hole, and a taper portion of the insertion hole, an outer peripheral surface of the tube, and a body A device for mounting a liquid temperature sensor, characterized in that an O-ring is sealed between the flange surface and the liquid temperature sensor. 6. An annular groove surrounded by the tapered portion of the insertion hole, the outer peripheral surface of the tube and the flange surface of the body has a substantially triangular cross section, and an O-ring is attached to the annular groove.
Mounting device for the liquid temperature sensor described. 7. A ripple in which a wide flange is formed at the base end of the tube and is substantially perpendicular to the axis of the tube, and substantially concentric convex portions and concave portions are alternately arranged on both surfaces of the flange portion. The device for mounting a liquid temperature sensor according to claim 5, wherein a concave-convex portion is formed.