JP2004012415A - Temperature sensor and manufacturing method of temperature sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature sensor capable of reducing the cost of the whole body furthermore by molding a sensor body and a sealing part integrally. <P>SOLUTION: In this temperature sensor 10, a temperature sensing element 17 is built in the sensor body 11, and the temperature sensing element side of the sensor body 11 is inserted into an attaching hole 8b formed on an attaching body 8, and the sensor body 11 and the attaching hole 8b of the attaching body 8 are attached in the airtight state through the sealing part 16 provided on the sensor body side. In the sensor 10, the sensor body 11 is molded by a resin, and an annular recessed part 13a is molded integrally on the position facing the attaching hole 8b of the sensor body 11, and the sealing part 16 is molded integrally so as to project to the outside with rubber in the annular recessed part 13a. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a temperature sensor such as a water temperature sensor suitable for measuring the temperature of engine cooling water of an automobile, for example, and a method of manufacturing the temperature sensor.
[0002]
[Prior art]
FIGS. 10 and 11 show such a temperature sensor. A water temperature sensor (temperature sensor) 1 shown in FIG. 10 has a substantially cylindrical metal case 2 containing a temperature sensing element 4 on the side of a closed portion 2a at the distal end, and a synthetic case integrally formed on the base end side of the metal case 2. And a box-shaped connector 3F made of resin. A male screw portion 2b is integrally formed at the center of the metal case 2, and a hexagonal portion 2c is integrally formed at a base portion of the metal case 2 so as to protrude. The bases of the pair of terminals are embedded in the connector 3F, and the bases of the terminals and the temperature sensing element 4 are connected by lead wires (both not shown).
[0003]
When the male screw portion 2b of the metal case 2 is screwed and fixed to, for example, a mounting screw hole (mounting hole) 8a formed in the engine outer wall (attached body) 8, the hexagonal portion 2c of the metal case 2 is fixed. An annular disk-shaped metal gasket 5 is interposed between the mounting screw hole 8a of the engine outer wall 8 and the surface around the mounting screw hole 8a to make the airtight state. The case 2 is prevented from leaking outside through the gap.
[0004]
A water temperature sensor (temperature sensor) 1 'shown in FIG. 11 includes a sensor body 3 made of synthetic resin. The sensor body 3 has a small-diameter cylindrical portion 3a having a temperature sensing element 4 built-in at the distal end, a large-diameter cylindrical portion 3b integrally formed with the small-diameter cylindrical portion 3a and having an annular concave portion 3c in the center, and a large-diameter cylindrical portion. A flange portion 3d integrally formed so as to extend at right angles to the cylindrical portion 3b, and a box-shaped connector portion 3f integrally formed at a position facing the large-diameter cylindrical portion 3b of the flange portion 3d are provided. ing. The bases of the pair of terminals are embedded in the connector 3f, and the bases of the terminals and the temperature sensing element 4 are connected by lead wires (both not shown).
[0005]
When the large-diameter cylindrical portion 3b of the sensor main body 3 is attached to, for example, a mounting hole 8b formed in the engine outer wall (the body to be mounted) 8, the large-diameter cylindrical portion 3b of the sensor main body 3 is assembled into the annular concave portion 3c. The rubber O-ring 6 is fitted into the mounting hole 8b, and the mounting screw 7 is screwed into the mounting screw hole 8c of the engine outer wall 8 through the screw insertion hole 3e of the flange 3d of the sensor body 3. As a result, the space between the mounting hole 8b of the engine outer wall 8 and the large-diameter cylindrical portion 3b of the sensor body 3 becomes airtight via the rubber O-ring 6, and the cooling water 9 in the engine outer wall 8 is connected to the mounting hole 8b. The sensor body 3 is prevented from leaking outside through a gap between the large-diameter cylindrical portions 3b.
[0006]
Incidentally, a similar technique relating to the temperature sensor 1 is disclosed in Japanese Patent Application Laid-Open No. 9-264795. A similar technique relating to the temperature sensor 1 'is disclosed in Japanese Patent Application Laid-Open No. 9-50830.
[0007]
[Problems to be solved by the invention]
However, in each of the conventional water temperature sensors 1 and 1 ', the metal gasket 5 and the rubber O-ring 6 are indispensable to prevent the cooling water 9 from leaking to the outside. Got higher. Further, in the conventional water temperature sensor 1, since there is no mechanism for fixing the metal gasket 5 to be attached to the metal case 2 side, it is necessary to separately manage the water temperature sensor 1 and the metal gasket 5 before assembling to the engine outer wall 8. Therefore, the number of man-hours for management increased and the cost increased. Further, in the conventional water temperature sensor 1 ', when the rubber O-ring 6 is assembled in the annular concave portion 3c of the large-diameter cylindrical portion 3b, whether the annular concave portion 3c has no scratches or burrs, or In addition, it is necessary to control the product, such as whether or not foreign matter is attached, and the number of man-hours for management is increased accordingly, resulting in high cost. In particular, the finished surface of the annular concave portion 3c of the large-diameter cylindrical portion 3b to which the rubber O-ring 6 is assembled is required to have a certain degree of accuracy in order to secure the sealing property. High manufacturing technology is required, and high-priced equipment and management man-hours increase.
[0008]
Therefore, the present invention has been made to solve the above-described problems, and a temperature sensor capable of further reducing the overall cost by integrally molding a sensor body and a seal portion, and a method of manufacturing the temperature sensor. The aim is to provide a method.
[0009]
[Means for Solving the Problems]
According to a first aspect of the present invention, a temperature sensing element is incorporated in a sensor main body, and the temperature sensing element side of the sensor main body is inserted into a mounting hole formed in a mounting body, and the sensor main body and the mounting body are mounted on the mounting body. A temperature sensor in which a body is hermetically mounted via a seal portion provided on the sensor main body side, wherein the seal portion is formed integrally with the sensor main body using an elastic material.
[0010]
In this temperature sensor, since a seal portion made of an elastic material is integrally formed on the sensor main body, retrofit parts such as a gasket and an O-ring which are indispensable in the past are not required. This reduces the number of components, eliminates the need for management of additional components, and reduces costs.
[0011]
The invention according to claim 2 is the sensor main body according to claim 1, wherein the sensor main body is formed of resin, and an annular concave portion is formed at a position of the sensor main body facing a mounting hole of the mounted body, It is characterized in that the seal portion is integrally formed in the annular concave portion so as to protrude outward.
[0012]
In this temperature sensor, since the sensor main body is formed of resin and the seal portion is integrally formed, an airtight state between the sensor main body and the mounting hole of the mounted body can be reliably obtained at a very low cost.
[0013]
According to a third aspect of the present invention, a temperature sensing element is built in the sensor main body, and the temperature sensing element side of the sensor main body is inserted into a mounting hole formed in the mounted body, and the sensor main body and the mounted body are mounted. A method for manufacturing a temperature sensor in which a body and a body are hermetically mounted via a seal portion provided on the sensor body side, wherein the temperature sensing element is set in a cavity formed in a primary molding die. In addition, in a state where the gate pin for forming the seal portion provided in the mold is set in the cavity, the cavity is filled with a molten material to fill the gate for forming the seal portion and an annular concave portion communicating with the gate. Then, the sensor body having primary sealing is formed in a cavity formed between a mold for secondary molding and an annular recess of the sensor body which has been primary molded. It is filled with a molten material, characterized in that the sealing portion is post-formed in the annular recess.
[0014]
In this method of manufacturing a temperature sensor, the sensor body and the seal portion are integrally formed in a short time by a small number of molding dies including a primary molding die and a secondary molding die, and a high-precision temperature is obtained. Sensors are mass-produced.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0016]
FIG. 1 is a sectional view showing a temperature sensor according to an embodiment of the present invention, FIG. 2 is a front view showing an attached state of the temperature sensor, and FIG. 3A is a front view of a sensor main body after primary molding of the temperature sensor. FIG. 3B is a sectional view of the sensor main body, and FIGS. 4 to 9 are sectional views sequentially showing an injection molding process of the temperature sensor.
[0017]
As shown in FIGS. 1 and 2, the water temperature sensor (temperature sensor) 10 includes a sensor body 11 made of synthetic resin. The sensor main body 11 has a small-diameter cylindrical portion 12 having a built-in thermistor (temperature sensing element) 17 for converting a change in the temperature of the engine cooling water 9 of an automobile into a change in electrical resistance at the distal end side, and the small-diameter cylindrical portion. 12, a large-diameter cylindrical portion 13 having an annular concave portion 13a formed at the center thereof, a mounting flange portion 14 integrally formed so as to extend at right angles to the large-diameter cylindrical portion 13, and A box-shaped connector portion 15 integrally formed at a position facing the large-diameter cylindrical portion 13 of the mounting flange portion 14 is provided.
[0018]
As shown in FIGS. 1 and 2, a rubber O-ring-shaped elastic seal portion (seal portion) 16 protrudes in an arc shape outside the annular concave portion 13 a of the large-diameter cylindrical portion 13 of the sensor main body 11. It is integrally formed as follows. Further, a thermistor 17 and a pair of lead wires 18 connected to the thermistor 17 and a pair of terminals 19 connected to the pair of lead wires 18 from the small-diameter cylindrical portion 12 to the connector portion 15 of the sensor body 11. , 19 are insert-molded.
[0019]
Then, as shown in FIG. 2, when the large-diameter cylindrical portion 13 of the sensor main body 11 is attached to, for example, a round mounting hole 8b formed in the engine outer wall (attached body) 8, an annular concave portion 13a of the sensor main body 11 is formed. The elastic seal portion 16 integrally formed therein is pressed against the inner surface of the mounting hole 8b, and the mounting screw 7 is screwed into the mounting screw hole 8c of the engine outer wall 8 through the screw insertion hole 14a of the mounting flange portion 14 of the sensor body 11. As a result, the space between the mounting hole 8b of the engine outer wall 8 and the large-diameter cylindrical portion 13 of the sensor main body 11 becomes airtight via the elastic seal portion 16, and the cooling water 9 in the engine outer wall 8 is separated from the mounting hole 8b and the sensor main body. 11 to prevent leakage to the outside. Since the elastic seal portion 16 is simply inserted into the mounting hole 8b and is not screwed, the outer surface of the elastic seal portion 16 is less likely to be damaged by rubbing against the inner surface of the mounting hole 8b, and the sealing property is sufficiently secured. Is done.
[0020]
Next, a method of manufacturing the water temperature sensor 10 of the embodiment will be described in order with reference to FIGS. 3 (a) and 3 (b) and FIGS. The injection mold 20 for two-color molding of the water temperature sensor 10 includes a fixed lower mold 22 and a pair of movable lower dies 23 and 23 serving as a lower mold 21 used for primary molding and secondary molding. The mold 25 includes a movable upper mold 26 for primary molding and a movable upper mold 28 for secondary molding. At the center of the upper surface of the fixed lower mold 22, a block 22c having a concave portion 22d for holding the pair of terminals 19, 19 is protruded. Further, a gate pin 24 for forming a seal portion is provided between the cavity 23a of the movable lower die 23 and the pair of slide cores 27 of the movable upper die 26 for primary molding so as to be movable forward and backward.
[0021]
As shown in FIG. 4, the lower mold 21 composed of the fixed lower mold 22 and the pair of movable lower molds 23, 23, the movable upper mold 26 for primary molding, and the upper mold 25 composed of the pair of slide cores 27, 27 are closed. To form the cavities 23a and 26a for molding the sensor body 11 of the water temperature sensor 10. Immediately before this closing, a pair of terminals 19, 19 connected to the thermistor 17 via a pair of lead wires 18, 18 are held in a pair of recesses 22d, 22d of a block 22c of the fixed lower mold 22, and the cavities 23a, The thermistor 17 and the like are set in 26a. Further, a gate pin 24 for forming a seal portion, which is provided on the lower mold 21 so as to be able to move forward and backward, is set in the cavities 23a and 26a.
[0022]
Then, in this state, when the molten resin P is filled into the cavities 23a and 26a from the gate 22a of the fixed lower mold 22, as shown in FIG. 3A, the sensor body 11 made of resin, the annular recess 13a and the From the mounting flange portion 14 of the sensor main body 11 to the large-diameter cylindrical portion 13, a gate 14b for forming a seal portion and an internal path 13b communicating from the gate 14b to the annular concave portion 13a are respectively primary molded.
[0023]
Next, as shown in FIG. 5, an upper mold 25 including a movable upper mold 26 for primary molding and a pair of slide cores 27, 27 is opened, and a gate pin 24 for forming a seal portion is retracted to lower the lower mold 21. Pull out from the movable lower mold 23. Then, as shown in FIG. 6, the lower mold 21 is moved from the station where the movable upper mold 26 for primary molding is provided to the station where the movable upper mold 28 for secondary molding is provided. Next, the upper mold 25 including the movable upper mold 28 for molding and a pair of slide cores 29, 29 is replaced.
[0024]
Next, as shown in FIG. 7, the upper mold 25 composed of the movable upper mold 28 for secondary molding and the pair of slide cores 29, 29 is closed, and the pair of slide cores 29, 29 and the annular shape of the sensor body 11 are closed. The molten rubber (elastic material) R is filled into the cavity 29 a formed between the recess 13 a and the sealing portion forming gate 22 b of the fixed lower mold 22. At this time, as shown by an arrow in FIG. 3B, the molten rubber R is transferred from the sealing portion forming gate 14b of the mounting flange portion 14 of the sensor body 11 to the annular concave portion 13a via the internal path 13b of the large-diameter cylindrical portion 13. Then, the elastic seal portion 16 is formed into the annular concave portion 13a so as to protrude outward in an arc shape.
[0025]
Then, as shown in FIG. 8, the upper mold 25 including the movable upper mold 28 for secondary molding and the pair of slide cores 29, 29 is opened, and as shown in FIG. When the lower dies 23, 23 are opened (molded), as shown in FIGS. 1 and 9, a water temperature sensor 10 formed by integrally molding a resin center body 11 and a rubber elastic seal portion 16 in two colors. Is completed.
[0026]
As described above, the annular concave portion 13a of the large-diameter cylindrical portion 13 of the resin-made sensor main body 11 primarily formed by the lower die 21 and the movable upper die 26 for primary molding, and the pair of slide cores 29, 29 are formed. The cavity 29a formed therebetween is filled with molten rubber R from the sealing portion forming gate 14b formed in the sensor main body 11 by the primary molding, so that the elastic sealing portion 16 is formed into an arc shape outward in the annular concave portion 13a. Since the secondary molding is performed so as to protrude, the sensor main body is formed by a small number of molding dies 20 including the movable upper mold 26 for primary molding, the movable upper mold 28 and the lower mold 21 for secondary molding. The two-color molding of the elastic seal part 11 and the elastic seal part 16 can be performed in a short time, and the high-precision temperature sensor 10 can be mass-produced.
[0027]
In addition, the sensor body 11 having the annular concave portion 13a formed in the center of the large-diameter cylindrical portion 13 is molded of resin, and the elastic seal portion 16 is integrally molded in the annular concave portion 13a so as to protrude outward with rubber. Retrofit parts, such as gaskets and O-rings, which have been indispensable in the past, become unnecessary, so that the number of parts can be reduced correspondingly, and the management of the retrofit parts becomes unnecessary, so that the cost can be reduced. In particular, as compared with the conventional O-ring assembly, maintenance and management of the processing accuracy of the finished surface of the O-ring mounting portion is not required, and the number of man-hours required for the maintenance can be significantly reduced, and the manufacturing cost of the water temperature sensor 10 can be reduced. Further lowering can be achieved. Thus, as shown in FIG. 2, when the large-diameter cylindrical portion 13 of the sensor body 11 is fitted into the mounting hole 8b of the engine outer wall 8 and attached, the large-diameter cylindrical portion 13 of the sensor body 10 and the engine outer wall 8 are attached. The airtight state with the mounting hole 8b can be reliably obtained at extremely low cost.
[0028]
According to the above-described embodiment, the sensor body integrally formed of a synthetic resin is used. However, a sensor body made of die-cast aluminum or magnesium may be used. Further, the seal portion is not limited to rubber, but may be made of a flexible resin such as an elastomer. Further, a gate pin for forming a seal portion is provided on the lower mold. However, when the temperature sensor is mounted, the gate is located on the outside of the body to be mounted, for example, on the engine cooling water 9 side inside the body to be mounted 8. Since the gate is not located at the position, no passage is formed between the inside and outside of the attached body 8 via the gate, which is preferable in terms of watertightness. Depending on the environment inside the attached body 8, the gate pin may be provided in the upper mold. good. Further, the secondary molded portion for integrally molding the seal portion is an annular concave portion molded at the center of the large-diameter cylindrical portion of the sensor body, but the shape of the secondary molded portion is not limited to the annular concave portion. In the case of a type without a mounting flange that forms an external thread on the large-diameter cylindrical part of the main body, the corner part at the boundary between the large-diameter cylindrical part of the sensor main body and the connector part (part facing the conventional gasket) May be used as a secondary molded portion of the seal portion. Further, although a thermistor is used as the temperature sensing element, another temperature sensing element such as a thermocouple may be used. Needless to say, the embodiment can be applied to an oil temperature sensor or the like that measures the oil temperature.
[0029]
【The invention's effect】
As described above, according to the temperature sensor of the first aspect of the present invention, since the seal portion is integrally formed of the elastic material with the sensor main body, retrofitting parts such as gaskets and O-rings which are conventionally indispensable become unnecessary. Accordingly, the number of parts can be reduced, and the management of post-installed parts becomes unnecessary, so that the cost can be reduced.
[0030]
According to the temperature sensor of the second aspect of the present invention, the sensor main body is formed of resin, and an annular concave portion is formed at a position facing the mounting hole of the attached body of the sensor main body, and a seal portion is formed in the annular concave portion. Since it is integrally formed so as to protrude outward, an airtight state between the sensor main body and the mounting hole of the mounted body can be reliably obtained at extremely low cost.
[0031]
According to the temperature sensor manufacturing method of the invention of claim 3, the cavity formed between the annular concave portion of the resin-made sensor main body primarily molded by the primary molding die and the secondary molding die. Since the molten material is filled from the seal forming gate formed on the sensor body by the primary molding to form the seal portion in the annular concave portion, the mold for the primary molding and the mold for the secondary molding are used. The sensor body and the seal portion can be integrally formed in a short time by using a small number of molding dies, and high-precision temperature sensors can be mass-produced.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a temperature sensor according to an embodiment of the present invention.
FIG. 2 is a front view showing a mounting state of the temperature sensor.
3A is a front view of the sensor main body after primary molding of the temperature sensor, and FIG. 3B is a cross-sectional view of the sensor main body.
FIG. 4 is a cross-sectional view of a molding die showing a closed state before the sensor body is primarily molded.
FIG. 5 is a cross-sectional view of a molding die showing an opened state of the sensor main body after primary molding.
FIG. 6 is a cross-sectional view of a molding die showing an open state of the sensor main body before secondary molding.
FIG. 7 is a cross-sectional view of a molding die showing a closed state when the sensor body is subjected to secondary molding.
FIG. 8 is a cross-sectional view of a molding die showing an opened state of the sensor main body after secondary molding.
FIG. 9 is a cross-sectional view of a molding die showing a mold split state of a lower die after the above-mentioned sensor main body is secondarily molded.
FIG. 10 is an explanatory diagram showing a mounting state of a conventional temperature sensor.
FIG. 11 is an explanatory view showing a mounting state of another conventional temperature sensor.
[Explanation of symbols]
8. Engine outer wall (attached body)
8b Mounting hole 10 Water temperature sensor (temperature sensor)
11 Sensor main body 13a Annular concave portion (secondary molded portion)
16 Elastic seal part (seal part)
17 Thermistor (temperature sensing element)
21 Lower mold 23a Cavity 24 Seal pin forming gate pin 25 Upper mold 26 Movable upper mold 26a for primary molding Cavity 28 Movable upper mold 28a for secondary molding Cavity P Molten resin (resin)
R molten rubber (elastic material)

Claims (3)

A temperature sensing element is built in the sensor body, the temperature sensing element side of the sensor body is inserted into a mounting hole formed in the body to be mounted, and the sensor body and the body to be mounted are connected to the sensor body side. A temperature sensor attached in an airtight state via a seal portion provided in
A temperature sensor, wherein the seal portion is integrally formed with an elastic material on the sensor main body. The sensor body according to claim 1, wherein
The sensor main body was formed of resin, and an annular concave portion was formed at a position of the sensor main body opposite to the mounting hole of the mounted body, and the seal portion was integrally formed in the annular concave portion so as to protrude outward. A temperature sensor, characterized in that: A temperature sensing element is built in the sensor body, the temperature sensing element side of the sensor body is inserted into a mounting hole formed in the body to be mounted, and the sensor body and the body to be mounted are connected to the sensor body side. A method for manufacturing a temperature sensor attached in an airtight state via a seal portion provided in
The temperature sensing element is set in a cavity formed in a mold for primary molding, and the gate pin for forming a seal portion provided in the mold is set in the cavity. The sensor body having a sealing portion forming gate and an annular concave portion communicating with the gate by filling a material is primarily molded, and then a secondary molding die and an annular concave portion of the primary molded sensor body are formed. A method for manufacturing a temperature sensor, comprising: filling a molten material from a gate for forming a seal portion into a cavity formed between the seal portions; and forming the seal portion in the annular recessed portion.

Images