JPH0575631U - Temperature sensor - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a temperature sensor 1 having high reliability and excellent water resistance. According to the present invention, at least the thermistor 3 and the lead wire are provided in a temperature sensor 1 including a thermistor 3 for detecting a temperature of a heat source and a lead wire 4 in which a conductor portion 4a at a tip end is connected to the thermistor 3. 4 has a urethane resin 5 that covers the conductor portion 4a and an epoxy resin 6 that covers the urethane resin 5. With this configuration, the stress acting on the thermistor 3 at the time of temperature change can be relaxed, the reliability is enhanced, and the water resistance is also improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to improvement of a temperature sensor used for detecting various temperatures of an air conditioner, a vending machine, and the like.

[0002]

[Prior Art]

 A conventional example of this type of temperature sensor is shown in FIG.

The temperature sensor 20 shown in FIG. 1 includes a case 21 having a bottom, a thermistor 23 arranged in the case 21, and a lead wire connected to the thermistor 23 at the end of the lead wire and led out to the outside of the case 21. 24, a phenolic undercoat resin 25 applied around the ends of the thermistor 23 and the lead wire 24, an epoxy overcoat resin 26 applied around the undercoat resin 25, and the inside of the case 21. And a hard epoxy-based filling resin 27 filled in a space around the overcoat resin 26.

The results of the defroster energization test and the hot water boiling energization test of the temperature sensor shown in FIG. 8 are shown in FIGS. 9 and 10.

In the defroster energization test, when a current of 0.5 mA is applied to the temperature sensor 20 and a large number of samples are immersed in water of −40 ° C. and + 60 ° C. for 4 hours each, the cycle is repeated many times. The remaining rate of non-defective products is calculated.

The hot water boiling current test shows the relationship between the remaining rate of non-defective products and time when a large number of samples are immersed in 90 ° C. hot water and a current of 0.5 mA is applied to the temperature sensor 20. It is something.

As shown in FIGS. 9 and 10, the temperature sensor 20 has a good result in the hot water boiling energization test, but a poor result in the defroster energization test. It will be about 40%.

FIG. 11 shows another conventional temperature sensor 30.

The temperature sensor 30 has substantially the same structure as the temperature sensor 20, except that a silicon resin is used as the undercoat resin 25a, an epoxy resin is used as the topcoat resin 26a, and a soft epoxy resin is used as the filling resin 27. Is used.

The results of the defroster energization test and the hot water boiling energization test of the temperature sensor 30 are shown in FIGS. 12 and 13.

As is clear from FIGS. 12 and 13, the temperature sensor 30 shown in FIG. 11 has a good defroster energization test result, but does not have a hot water boiling energization test result, and is a non-defective product after 1,000 hours. The remaining rate of is about 20%.

[0012]

[Problems to be solved by the device]

 As described above, in the case of the conventional temperature sensor 20 filled with a hard epoxy resin, the water resistance is good, but since the undercoating resin 25 and the filling resin 27 are hard, the stress acting on the thermistor 23 at the time of temperature change is relaxed. However, there is a problem in terms of reliability (heat cycle property).

Further, the conventional temperature sensor 30 filled with a soft epoxy resin has a problem in water resistance.

Therefore, the present invention aims to provide a temperature sensor having high reliability and excellent water resistance.

[0015]

[Means for Solving the Problems]

 According to the present invention, in a temperature sensor including a thermistor for detecting the temperature of a heat source and a lead wire connecting a conductor portion at a tip end to the thermistor, at least the thermistor and the conductor portion of the lead wire are surrounded. It has a urethane resin for covering and an epoxy resin for covering this urethane resin.

[0016]

[Action]

 The operation of the temperature sensor will be described below.

According to this temperature sensor, since the circumference of the thermistor and the conductor portion of the lead wire is covered with the soft and water-resistant urethane resin, the stress acting on the thermistor when the temperature changes can be relaxed. Also, the water resistance becomes good, and it is possible to use a soft epoxy resin having poor water resistance as the filling resin.

[0018]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail.

A temperature sensor 1 shown in FIG. 1 has a case 2 having a bottom, a thermistor 3 arranged in the case 2, and a conductor portion 4 a at the end of the lead wire connected to the thermistor 3 and a case 2 The lead wire 4 led out to the outside, the thermistor 3 and the conductor portion 4a of the lead wire 4, and a soft and water-resistant polybutadiene-based urethane resin 5 applied to the surrounding area of the urethane resin 5. It is equipped with an epoxy-based coating resin 6 and an epoxy-based filling resin 7 filled in the area surrounding the epoxy-based coating resin 6.

FIG. 2 shows another embodiment of the present invention.

The temperature sensor 1A shown in FIG. 2 is one in which the epoxy-based coating resin 6 of the temperature sensor 1 shown in FIG. 1 is deleted and the amount of the urethane resin 5 applied is increased instead.

FIG. 4 shows the results of the defroster energization test of the temperature sensor 1 shown in FIG. 1, and FIG. 5 shows the results of the hot water boiling energization test. The defroster energization test and the hot water boiling energization test were performed in the same manner as in the conventional example.

FIG. 6 shows the results of the defroster energization test of the temperature sensor 1A shown in FIG. 2, and FIG. 7 shows the results of the hot water boiling energization test.

As is apparent from FIGS. 4, 5 and 6 and 7, in the case of the temperature sensors 1 and 1A shown in FIGS. 1 and 2, the results of the defroster energization test and the hot water boiling energization test are both Good, the remaining rate of non-defective products remains 100% for up to 300 cycles and 3000 hours, extremely high reliability and good water resistance.

That is, in the case of the temperature sensor 1 shown in FIG. 1, since the urethane resin 5 which is soft and has good water resistance is used as the undercoat resin, both heat cycle characteristics and water resistance characteristics are good.

The case of the temperature sensor 1A shown in FIG. 2 is similar to that of the temperature sensor 1 shown in FIG.

FIG. 3 shows still another embodiment of the present invention.

The temperature sensor 1B shown in FIG. 3 is obtained by removing the case 2 and the filling resin 7 of the temperature sensor 1 shown in FIG.

Also in the case of such a temperature sensor 1B, it is possible to exhibit the same operation as in the case of each of the temperature sensors 1 and 1A shown in FIGS.

The present invention can be modified in various ways within the scope of the invention in addition to the detailed embodiment.

[0031]

According to the present invention described above, since it has the above-mentioned configuration, it is possible to provide a temperature sensor having excellent reliability and excellent water resistance.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing another embodiment of the present invention.

FIG. 3 is a sectional view showing still another embodiment of the present invention.

FIG. 4 is a graph showing the results of a defroster electrification test of the temperature sensor shown in FIG.

5 is a graph showing the results of a hot water boiling current test of the temperature sensor shown in FIG.

6 is a graph showing the results of a defroster electrification test of the temperature sensor shown in FIG.

7 is a graph showing the results of a hot water boiling current test of the temperature sensor shown in FIG.

FIG. 8 is a sectional view of a conventional temperature sensor.

9 is a graph showing the results of a defroster electrification test of the temperature sensor shown in FIG.

10 is a graph showing the results of a hot water boiling current test of the temperature sensor shown in FIG.

FIG. 11 is a sectional view showing another example of a conventional temperature sensor.

12 is a graph showing the results of a defroster electrification test of the temperature sensor shown in FIG.

13 is a graph showing the results of a hot water boiling current test of the temperature sensor shown in FIG.

[Explanation of symbols]

 1 Temperature Sensor 2 Case 3 Thermistor 4 Lead Wire 4a Conductor 5 Urethane Resin 6 Epoxy Resin

Claims (1)

[Scope of utility model registration request] 1. A temperature sensor comprising a thermistor for detecting various temperatures of a heat source and a lead wire connecting a conductor portion at a tip portion to the thermistor, at least around the thermistor and the conductor portion of the lead wire. A temperature sensor comprising: a urethane resin covering the epoxy resin; and an epoxy resin covering the urethane resin.