JPH0915062A - Thermistor type temperature detector and molding method therefor - Google Patents

Abstract

PURPOSE: To enhance the sealing performance between aN opening part of a metal case and the thick part of a resin body being fitted into the opening part. CONSTITUTION: A connector housing 9 has a double structure of first and second molded parts 9a, 9b and the thick part of connector housing comprises a combination of parts 91a, 92a. At the time of molding the parts 9a, 9b, shrinkage at each part 91a, 91b is suppressed as compared with conventional thick part of single layer structure. Since the shrinkage is also suppressed at a groove part 94b made in the part 91b, the gap between the groove part 94b and an O-ring 10 is reduced thus enhancing the sealing performance between the connector housing 9 and the sensor case 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature detector in which a resin body obtained by resin-molding a thermistor is fitted in a metal case.

[0002]

2. Description of the Related Art For example, in Japanese Utility Model Laid-Open No. 52-9479, an inner space of a metal case is covered with an insulating tube.
Suspend the first thermistor with a lead wire, and
A temperature detector in which a second thermistor is fixed to the bottom of the metal case is disclosed. In this conventional technique, when the first thermistor is assembled in a metal case, the first thermistor is inserted into the metal case, and in addition, an insulating tube is passed through the two lead wires. Since the process is also required, there was a problem that assembly workability was poor.

Therefore, the applicant of the present invention is an invention (Japanese Patent Application No. 6-
No. 201081) was filed first. An example of the invention described in this prior application will be briefly described with reference to FIG. 9. Connector terminals 6a, 6b and these terminals 6a, 6
The lead wires 7a and 7b electrically connected to b, the first thermistor 8 electrically connected to the lead wires 7a and 7b, and the connector terminal 6c are integrally resin-molded to form the thick portion 91 and The connector housing 9 including the thin portion 92 is molded.

Then, after other necessary members are incorporated in the metal sensor case 1 consisting of the small diameter portion 1a, the medium diameter portion 1b and the large diameter portion 1c, the resin-molded connector housing 9 is attached to the sensor case. 1 and then the caulking portion 1e formed on the large diameter portion 1c of the sensor case 1 is inserted downward in the drawing so as to sandwich the protruding portion 93 formed on the thick portion 91 of the connector housing 9. It is caulking. As a result, the connector housing 9 is fixed to the sensor case 1.

Further, the O-ring 10 is fitted into the groove portion 94 formed by forming the protruding portion 93, and the O-ring 10 is
Ring 10 for connector housing 9 and sensor case 1
The seal is between. As described above, in the above-mentioned prior application, the temperature detector can be molded by a simple operation of inserting the connector housing 9 into the sensor case 1 and caulking it.

[0006]

In the method of molding the connector housing 9, first of all, the connector terminals 6a to 6a are formed.
c, the lead wires 7a, 7b, and the first thermistor 8 are put into a predetermined mold, then a muddy resin is injected into this mold at a high temperature, and when the resin is hardened, the mold is removed. is there.

By the way, since the thick wall portion 91 of the connector housing 9 is thicker than the thin wall portion 92, immediately after the muddy resin is poured into the mold, the resin is placed outside the thick wall portion 91. (For example, the protruding portion 93) immediately hardens, but does not harden inside yet. When the connector housing 9 is removed from the mold in this state, the resin on the inner side gradually hardens, but along with this, the resin on the outer side which has already hardened is pulled inward, and as a result, A sink mark occurs in the resin on the outside.

The occurrence of sink marks in the resin on the outside as described above means that sink marks may also occur in the groove portions 94. In this case, the groove portions 94 in which the sink marks have occurred and the O-ring. There is a gap between the connector housing 9 and the sensor case 1, and as a result, there is a problem in that the connector housing 9 and the sensor case 1 cannot be sealed. In addition, this problem is, in essence, a temperature sensor formed by fitting a resin body integrally molded with a thermistor and a metal wire connected to the thermistor into an opening of a metal case, This occurs in a temperature detector in which a thick portion and a thin portion are formed in a resin body and a space between the thick portion of the resin body and the opening of the metal case is sealed by a sealing member such as an O-ring. It is a thing. Therefore, with such a temperature detector, the above-mentioned problem occurs even if the number of thermistors housed in the metal case is one or more.

In view of the above problems, the present invention provides a temperature detector formed by fitting a resin body integrally molded with a thermistor and a metal wire connected thereto with an opening of a metal case. A temperature detector in which a thick portion and a thin portion are further formed in the resin body, and a space between the thick portion of the resin body and the opening of the metal case is sealed by a seal member, An object of the present invention is to improve the sealing property between the thick portion of the resin body and the opening of the metal case.

[0010]

In order to achieve the above object, in the invention according to claim 1, a metal having a space inside and further having an opening (1a) for communicating this space with the outside is formed. The case (1), the thermistor (8), and metal wires (7a, 7a) electrically connected to the thermistor (8).
b) is integrally resin-molded and molded,
A resin body (9) in which a thick portion (91a, 91b) and a thin portion (92a) are formed, and the thick portion (91a, 91b) is fitted into the opening (1c) of the metal case (1). )When,
A seal member (10) for sealing the opening (1c) of the metal case and the thick portion (91a, 91b) of the resin body.
A thermistor-type temperature detector comprising: a resin body (9), the first thermistor (8) and the metal wires (7a, 7b) being resin-molded in a first mold part (9).
a) and a part (91a) of this first mold part (9a)
A second mold part (91b) formed on the outer surface of the first mold part, and the thick part (91a, 91b) of the resin body is a part of the first mold part (91a) and the second mold part. A thermistor type temperature detector configured by a combination with (91b).

According to a second aspect of the invention, in the thermistor type temperature detector according to the first aspect, a part (91a) of the first mold portion and the second mold portion (91b).
Is characterized by being molded with resin of the same material.
According to a third aspect of the invention, in the thermistor type temperature detector according to the first or second aspect, the seal member (1
0) is the second resin body (91b) of the thick portions (91a, 91b) and the opening (1c) of the metal case.
It is characterized in that it is provided at a position to seal and.

According to a fourth aspect of the present invention, in the thermistor type temperature detector according to any one of the first to third aspects, another thermistor different from the thermistor (8) is provided in the metal case (1). (3) is stored. In the invention according to claim 5, a metal case (1) having a space inside and further having an opening (1c) communicating with the space, a thermistor (8) and this thermistor (8). The metal wires (7a, 7b) electrically connected to each other are integrally resin-molded and molded, and the thick portions (91a, 91b) and the thin portion (92a) are formed. 91a, 91
b) seals the resin body (9) fitted in the opening (1c) of the metal case, the opening (1c) of the metal case and the thick portion (91a, 91b) of the resin body. A method for molding a thermistor type temperature detector including a seal member (10), comprising: forming a resin body (9), the thermistor (9) and the metal wires (7a, 7b) in a first molding die (101). 10 to 103), and the first mold (10
1 to 103), a first mold part molding step of molding a first mold part (9a) by injecting and solidifying a resin into the first mold part and a second part of the first mold part (91a).
The second mold (201-205) is put into a mold (201-205), a resin is injected into the second mold (201-205) to be solidified, and a second mold is formed on an outer surface of a part (91a) of the first mold part. A second mold part forming step of forming the part (91b), and a part (91a) of the first mold part.
And the second mold part (91b), the second mold part (91b) of the thick parts (91a, 91b) and the opening (1) of the metal case.
c) and the sealing member (10) so as to sandwich it,
A method for forming a thermistor type temperature detector, which is formed by inserting the thick portions (91a, 91b) into the opening (1c), is characterized.

The reference numerals in parentheses of the above-mentioned means indicate the correspondence with the concrete means of the embodiments described later.

[0014]

According to the present invention, the resin body formed by integrally resin-molding the thermistor and the metal wire has a structure in which a thick portion and a thin portion are formed. Further, the thick portion is configured by a combination of a part of the first mold portion and the second mold portion. In this case, the wall thickness of each of the mold parts is smaller than the wall thickness of the thick part formed of a single molded body as in the conventional case.

As a result, the amount of sink mark generated in each mold portion during molding of the resin body is smaller than the amount of sink mark generated in the conventional thick portion. In other words, the amount of sink mark generated in the thick part composed of the combination of these mold parts is
The amount is smaller than the amount of sink marks generated in the conventional thick portion. In the temperature detector of the present invention, the thick portion is fitted into the opening of the metal case, and the thick portion and the opening are formed by sealing with the sealing member. Since the amount of sink marks generated in the thick portion formed by the combination of the mold portions is small, it is difficult to form a gap between the thick portion and the seal member. Therefore, it is possible to sufficiently secure the sealing property between the thick portion of the resin body and the opening of the metal case.

In particular, according to the second aspect of the invention, since a part of the first mold part and the second mold part are molded with the resin of the same material, mutual adhesion of these mold parts is improved. In the molding method as claimed in claim 5, the first mold part is first molded in the first mold part molding step, and then the second mold part molding step is performed.
The resin body is molded in the order of molding the second mold part on the outer surface of a part of the first mold part.

In this case, even if some sink marks are generated on the surface of the part of the first mold part, the surface of this part is
Resin molding is performed in the second molding part molding step.
Therefore, finally, only the sink mark generated on the surface of the second mold portion affects the sealing property between the second mold portion and the metal case opening. Here, as described above, since the amount of sink mark generated in the second mold portion is smaller than that in the conventional one, a gap is less likely to be formed between the second mold portion and the seal member, and as a result, The sufficient sealability between the two-molded portion and the metal case can be ensured.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 is a cross-sectional view showing the overall structure of the temperature detector of this embodiment, which is a vertical cross-sectional view of FIG. 2 is a front view of the temperature detector, and FIG. 3 is a top view of the temperature detector. As shown in FIG. 1, the temperature detector in this embodiment includes a sensor case 1 made of metal (brass in this embodiment) and a resin (specifically, nylon) attached to the base end side of the sensor case 1. It is mainly composed of a connector housing 9 made of resin.

The sensor case 1 has a cylindrical small-diameter portion 1a formed on the bottom side, a cylindrical medium-diameter portion 1b formed above the small-diameter portion 1a in the drawing, and a middle-diameter portion 1b of the cylindrical shape in the drawing. It is composed of a cylindrical large-diameter portion 1c formed above. The threaded portion 1d formed on the medium diameter portion 1b is engaged with a pipe passage for engine cooling water (not shown), so that the medium diameter portion 1b and the small diameter portion 1a are immersed in the engine cooling water. There is.

Further, the sensor case 1 is provided on the large diameter portion 1c.
An opening is formed that communicates the internal space of the device with the outside.
Further, a caulking portion 1e is formed on the large diameter portion 1c over the entire circumference. The caulking portion 1e has a shape in which a part of the entire circumference is different from the other portion, and the other portion prevents the connector terminal 9 from rotating.

The connector housing 9 includes a first mold portion 9a and an upper portion 91 of the first mold portion 9a in the figure.
A second molded portion 9 formed by resin-molding the outer peripheral portion of a.
b) and both are made of the same resin material. As described above, since the connector housing 9 has the second mold portion 9b molded around the portion 91a, the combination of the portion 91a and the second mold portion 91b around the portion 91a has a thick portion. The remaining first mold portion 92a is a thin portion.

The first mold portion 9a has connector terminals 6a, 6b made of metal, and these terminals 6 are provided.
metal lead wires 7a, 7 electrically connected to a, 6b
b, the first thermistor 8 electrically connected to these lead wires 7a and 7b by soldering, and the metal connector terminal 6c are integrally resin-molded. The lead wires 7a and 7b are covered with an insulating tube. In addition, the above-mentioned connector terminal 6
The lower end portion of c in the drawing is bent toward the front side of the drawing and reaches the ring-shaped lower end portion 12 made of metal.

The second mold portion 9b has the portion 91
b, and a portion 92b formed on the upper side of the portion 91b in the drawing. Of these, the part 91
A projecting portion 93b projecting over the entire circumference is formed on b. Further, a groove portion 94b is formed on the entire lower surface of the protruding portion 93b, and an elastic body (specifically, an O ring) 10 made of resin is fitted into the groove portion 94b.

On the other hand, a ring-shaped second thermistor 3 is provided on the upper surface of the bottom portion 1f of the intermediate diameter portion 1b and around the first mold portion 9a, and further on the upper surface of the second thermistor 3 and A ring-shaped conducting member 4 made of metal (specifically, brass whose surface is plated with nickel) is provided around the mold portion 9a.
An elastic body (specifically, a coil spring) 13 made of metal is provided between the conductive member 4 and the lower end portion 12 and around the first mold portion 9a, and the medium diameter portion 1b. An insulating cylinder 5 made of an insulating material (for example, nylon) is fitted on the inner peripheral surface of the.

The thick portion, that is, the portion 9
When the combination of 1a and 91b is fitted in the opening formed in the large diameter portion 1c of the sensor case 1, the caulking portion 1e is caulked downward in the drawing, so that the connector terminal 9 is moved to the sensor. It is fixed to the case 1. As a result, the O-ring 10 reliably seals between the groove portion 94b and the large diameter portion 1c.

At this time, the lower end 12 presses the coil spring 13 downward in the drawing, whereby the conducting member 4
And the second thermistor 3 comes into close contact with the bottom portion 1f. The thickness of the protrusion 93b in the vertical direction in the figure is
It goes without saying that the caulking portion 1e is thick enough to withstand the stress when caulking. Further, 15 is an O-ring.

Next, the first thermistor 8 and the second thermistor 3 will be described in detail. The first thermistor 8 is used as a thermistor for electronically controlled fuel injection control. More specifically, the connector terminal 6
a and 6b are connected to a circuit (not shown) for electronically controlled fuel injection control. Here, since the resistance value of the first thermistor 8 changes depending on the temperature, the potential difference across the first thermistor 8 changes according to the temperature of the first thermistor 8 when a constant current flows from the circuit. Therefore, in the present embodiment, the above circuit is configured to input the potential difference between both ends of the first thermistor 8, calculate the water temperature backward from this potential difference, and perform fuel injection control using this detected water temperature.

The second thermistor 3 is used as a thermistor for a water temperature gauge provided on an instrument panel of a car. More specifically, the connector terminal 6c is connected to the battery via a water temperature gauge display portion (not shown), and the sensor case 1 is connected to the engine cooling water pipe. Therefore, the current from the battery is indicated by the water temperature indicator → connector terminal 6c → lower end 1
The current flows in the order of 2 → coil spring 13 → conductive member 4 → second thermistor 3 → sensor case 1 → engine cooling water piping → engine → ground.

Since the resistance value of the second thermistor 3 changes depending on the temperature, the amount of the current changes according to the temperature of the second thermistor 3 when a constant voltage is applied from the battery. Therefore, the amount of current flowing through the water thermometer display portion changes, which changes the amount of deflection of the pointer of the water thermometer. Next, a method for molding the connector housing 9 will be described with reference to FIGS.

FIG. 4 is a vertical sectional view showing a state where the first mold portion 9a is molded by the molding dies 101 to 103.
FIG. 5 is a vertical cross-sectional view of the first mold portion 9a, and FIG. 6 shows a state in which the connector housing 9 including the first mold portion 9a and the second mold portion 9b is molded by the molding dies 201 to 205. FIG. 7 is a vertical sectional view and FIG. 7 is a vertical sectional view of the connector housing 9.

First, the first mold part molding step of molding the first mold part 9a using the first molds 101 to 103 will be described with reference to FIG. First, by fitting the connector terminals 6 a to 6 c into the first molding die 101, the connector terminals 6 a are formed in the first molding die 101.
6c, lead wires 7a and 7b, and first thermistor 8
To grip. After that, from the both sides in the figure, the first mold 102,
Match 103. Then, a thick resin (nylon) is injected at a high temperature (about 280 ° C.) from a resin injection port (not shown). And once this resin has set,
The molds 10 to 103 are removed to mold the first mold portion 9a.

Next, a second mold for molding the connector housing 9 by molding the second mold portion 9b on the outer surface of the portion 91a of the first mold portion 9a using the second molding dies 201-205. The part forming step will be described with reference to FIG. First, the molded first mold portion 9a is sandwiched between the second molding dies 201 and 202. Then, align the second molding dies 203 and 204 from both sides in the figure,
Finally, the second molding die 205 is fitted from above in the figure.

Then, a high temperature (about 2
Inject a thick resin (nylon) at 90 ° C. Then, when this resin is solidified, each second molding die 20
1 to 205 are removed to form the second mold portion 9b. As a result, the first mold portion 9a and the second mold portion 9b
The connector housing 9 consisting of and is molded. Next, a method of forming the temperature detector will be described.

The insulating cylinder 5 is fitted into the inside of the sensor case 1 formed by cutting the surface and the inside of the hexagonal brass, and then the second thermistor 3, the conducting member 4, and the coil spring 13 are placed inside the sensor case 1. To insert. Then, after fitting the O-ring 10 into the groove portion 94b of the connector housing 9 molded by the above-described molding method, the thin portion of the connector housing 9 is inserted into the coil spring 13 so that the thickness of the connector housing 9 is increased. The meat portion is fitted into the opening of the large diameter portion 1c, and the caulking portion 1d is caulked. The temperature detector is molded by the above method.

As described above, in this embodiment, the thick portion of the connector housing 9 is formed of a combination of the portion 91a of the first mold portion 9a and the portion 91b of the second mold portion 9b. That is, the thick portion of this embodiment is composed of a portion 91a and a portion 91b having a smaller thickness than the thick portion of the connector housing 9 shown in FIG.

Therefore, both the amount of sink marks generated in the portion 91a in the first molding portion molding step and the amount of sink marks generated in the portion 91b in the second molding portion molding step, the thickness of the connector housing 9 in FIG. It is less than the amount of sink marks generated in the meat. That is, the respective portions 91a of the present embodiment,
The amount of sink mark generated in the thick portion made of the combination of 91b is smaller than the amount of sink mark generated in the thick portion in the example of FIG.

Therefore, the amount of sink mark generated in the portion contacting the O-ring 10 in the thick portion of this embodiment, that is, the groove portion 94b is smaller than the amount of sink mark generated in the groove portion 94 of the example of FIG. Therefore, as compared with the example of FIG. 9, a gap is less likely to be formed between the groove portion 94b and the O-ring 10. Therefore,
As compared with the example of FIG. 9, the sealing property between the groove portion 94b and the large diameter portion 1c can be improved.

Further, in this embodiment, when the first mold portion 9a is molded in the first mold portion molding step, even if the surface of the portion 91a is slightly jagged due to sink marks, the second mold portion 9a In the molding process, the notched surface is resin-molded. Therefore, the problem of the gap between the thick portion and the O-ring 10 caused by the sink mark is related only to the amount of the sink mark generated in the portion 91b of the second mold portion 9b. As described above, since the thickness of the portion 91b is smaller than the thickness of the thick portion of FIG. 9, the gap between the portion 91b and the O-ring 10 should be smaller than that of the example of FIG. You can

Further, in this embodiment, since the first mold portion 9a and the second mold portion 9b are molded with the resin of the same material, compared with the case where these mold portions 9a, 9b are molded with the resin of different materials, respectively. Each mold part 9a,
It is possible to improve the mutual adhesiveness of 9b. Next, a second embodiment of the present invention will be described.

As shown in FIG. 8, a projecting portion 93a that projects over the entire circumference is formed at a portion 91a of the first mold portion 9a, and this projecting portion 93a cuts into the middle of the projecting portion 93b of the second mold portion 9b. The shape may be good. In this case, since the second mold portion 9b becomes more uniform in thickness,
The amount of sink marks generated in the mold portion 9b is reduced. That is, a gap between the second mold portion 9b and the O-ring 10 is less likely to occur.

(Modification) In each of the above examples, the sensor case 1
An example in which the second thermistor 3 is provided inside the resin in addition to the resin-molded first thermistor 8 has been described.
The second thermistor 3 and members associated therewith (conduction member 4, coil spring 13, connector terminal 6)
You may lose c). On the contrary, three or more thermistors may be provided in the sensor case 1.

Further, in each of the above examples, the connector terminal having a double structure of the first mold portion 9b and the second mold portion 9b is molded by the first mold portion molding step and the second mold portion molding step. The connector terminal 9 having a triple structure may be formed by the step of forming the mold portion. In addition, a substance having electrical insulation and good thermal conductivity (for example, silicon oil) may be injected into the middle diameter portion 1b. By doing so, the second thermistor 3
The thermal response of is improved. Further, at this time, as the amount of the silicone oil, it is more preferable to always inject the silicone oil so that the periphery of the second thermistor 3 is immersed in the silicone oil regardless of the posture of the temperature detector.

In each of the above examples, the lead wires 7a and 7b and the first thermistor 8 are both resin-molded, but only the lead wires 7a and 7b are resin-molded to expose the first thermistor 8. May be.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing the overall configuration of a temperature detector according to a first embodiment of the present invention.

FIG. 2 is a front view of the temperature detector.

FIG. 3 is a top view of the temperature detector.

FIG. 4 shows the first mold portion 9a of the above-described embodiment with the molding die 10
It is a longitudinal cross-sectional view showing a state of being molded by 1 to 103.

FIG. 5 is a vertical sectional view of the first mold portion 9a.

FIG. 6 is a view showing a molding die 2 in which the connector housing 9 of the above embodiment is used.
It is a longitudinal cross-sectional view showing a state of being molded by 01 to 205.

FIG. 7 is a vertical cross-sectional view of the connector housing 9.

FIG. 8 is a vertical sectional view showing the overall configuration of a temperature detector according to a second embodiment of the present invention.

FIG. 9 is a vertical cross-sectional view showing the overall configuration of an embodiment of the temperature detector in the prior application (Japanese Patent Application No. 6-201081).

[Explanation of symbols]

1 ... Sensor case, 3 ... 2nd thermistor, 6a-6c ...
Connector terminal, 7a, b ... Lead wire, 8 ... First thermistor, 9 ... Connector housing, 9a ... First mold part, 9b ... Second mold part, 10 ... O-ring, 101
103 ... 1st shaping | molding die, 201-205 ... 2nd shaping | molding die.

Claims (5)

[Claims] 1. A metal case having a space inside and further having an opening for communicating the space with the outside, a thermistor and a metal wire electrically connected to the thermistor are integrally resin-molded. As it is molded,
A resin body in which a thick portion and a thin portion are formed, and the thick portion is fitted into the opening of the metal case, and a seal for sealing the opening of the metal case and the thick portion of the resin body A thermistor type temperature detector including a member, wherein the resin body is molded on a first mold part obtained by resin-molding the thermistor and the metal wire, and a part of an outer surface of the first mold part. Second
A thermistor type temperature detector, comprising: a mold part, wherein the thick part of the resin body is a combination of a part of the first mold part and the second mold part. 2. The thermistor type temperature detector according to claim 1, wherein a part of the first mold part and the second mold part are molded of resin of the same material. 3. The seal member is provided at a position that seals the second resin body and the opening of the metal case in the thick portion.
The thermistor type temperature detector described. 4. The thermistor type temperature detector according to claim 1, wherein another thermistor different from the thermistor is housed in the metal case. 5. A metal case having a space inside and further having an opening formed therein for communicating the space with the outside, a thermistor and a metal wire electrically connected to the thermistor are integrally resin-molded. As it is molded,
A resin body in which a thick portion and a thin portion are formed, and the thick portion is fitted into the opening of the metal case, and a seal for sealing the opening of the metal case and the thick portion of the resin body A method for molding a thermistor type temperature detector including a member, wherein the resin body is placed in a first molding die with the thermistor and the metal wire, and resin is injected into the first molding die. A first mold part forming step of forming a first mold part by solidifying; a part of the first mold part is put into a second mold; and a resin is injected into the second mold to solidify. And a second mold part forming step of forming a second mold part on the outer surface of a part of the first mold part, and a combination of a part of the first mold part and the second mold part. The second part of the thick part composed of In the Rudo portion and the opening of the metal case, so as to sandwich the sealing member, a molding method of a thermistor type temperature detector, characterized in that it is formed by inserting the thick portion in the opening.