JP4107058B2 - Temperature sensor for heat exchanger - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a temperature sensor for a heat exchanger that detects the temperature of fins in a heat exchanger.
[0002]
[Prior art]
For example, a cooling device in an air conditioner such as an automobile is composed of an evaporator, a compressor, etc., and the evaporator as a heat exchanger exchanges heat between the refrigerant pumped by the compressor and the air in the vehicle interior, etc. It has a function of cooling air.
[0003]
An evaporator temperature sensor that detects the temperature of air after passing through the evaporator is installed on the leeward side of the evaporator. Based on the temperature detected by the sensor, the evaporator fins are prevented from freezing. ON / OFF control is performed to control the pumping amount of the refrigerant.
[0004]
Thus, the evaporator temperature sensor plays an important role for preventing the evaporator from freezing, and various devices have been devised to detect the temperature with higher accuracy.
[0005]
For example, in the technique disclosed in Patent Document 1, a holder is integrally provided on the refrigerant passage plate of the evaporator, and the temperature sensor for the evaporator is fixed by the holder, so that the temperature detection element is firmly attached to the leeward side of the evaporator. It is intended to fix the temperature detection accuracy.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 6-48164
[Problems to be solved by the invention]
However, the temperature detection sensor for an evaporator disclosed in Patent Document 1 measures the temperature of the heat-exchanged air instead of the temperature of the evaporator fin in order to prevent the evaporator fin from freezing. Accordingly, there is a problem that when the air volume is reduced due to frost on the fins or filter clogging installed before the evaporator, accurate detection cannot be performed due to the influence.
[0008]
An object of this invention is to provide the temperature sensor for heat exchangers which improved the temperature detection precision in view of the said problem.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the temperature sensor for a heat exchanger according to claim 1 includes a sensor part including a temperature detection element, a lead part electrically connected to the temperature detection element, and a case for housing the sensor part. The case is smaller than the air passage between the housing portion for housing the sensor portion and the fins of the heat exchanger, and is housed at an angle of approximately 90 degrees with respect to the longitudinal direction of the housing portion. It has the extension part integrally formed in the part. And in the state fixed to the heat exchanger, the extending part is in contact with the fin while being inserted into the air passage , and a part of the storage part is in contact with the end face of the fin .
[0010]
As described above, in the temperature sensor for the heat exchanger , the extending portion smaller than the air passage between the fins is formed integrally with the storage unit at an angle of about 90 degrees with respect to the longitudinal direction of the storage unit. Has been. And the extension part in a case and a part of accommodating part are contacted with a fin in the fixed state to a heat exchanger. Therefore, the temperature detection element of the sensor unit can accurately detect the temperature of the fin of the heat exchanger itself through the case having the extending part. Moreover, since the case is brought into contact with the fin at two locations including the extending portion, the heat exchanger temperature sensor can be fixed to the heat exchanger in a more stable state. Furthermore, since the sensor itself can be arranged substantially parallel to the surface of the heat exchanger, the installation space can be reduced.
[0011]
According to a second aspect of the present invention, at least a part of the sensor unit may be in contact with the inner wall of the storage unit in the case . Thereby, the thermal conductivity from the case to the sensor unit is improved, and the temperature detection accuracy of the temperature detection element is improved.
[0012]
According to a third aspect of the present invention, it is preferable that a resin is filled between the sensor unit stored in the case and the inner wall of the storage unit in the case . By filling the resin, the sensor unit is protected and the sensor unit is fixed in the case (in the storage unit ) . In addition, heat is preferably transmitted from the case to the sensor unit via the resin.
[0013]
As described in claim 4, the case is preferably made of metal. If the case is formed of a metal having excellent thermal conductivity, the temperature of the fins of the heat exchanger is efficiently transmitted to the temperature detection element, and as a result, the temperature can be detected with higher accuracy.
[0015]
According to a fifth aspect of the present invention, it is preferable that the extending portion is provided with a drop-off preventing means on at least a surface in contact with the fin. By providing a drop prevention means on at least the surface of the extending portion that contacts the fin, the heat exchanger temperature sensor can be firmly fixed to the fin surface of the heat exchanger.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
The temperature sensor for a heat exchanger in the present embodiment is suitable for measuring the temperature of the fins of the heat exchanger, and is particularly an evaporator used for an air conditioner such as a vehicle and a consumer air conditioner or other cooling equipment. Can be suitably used as a temperature sensor for preventing freezing of fins. In the present embodiment, an evaporator temperature sensor is shown as an example of a heat exchanger temperature sensor, FIG. 1A is a cross-sectional view, and FIG. 1B is a perspective view.
[0017]
As shown in FIG. 1A, an evaporator temperature sensor 1 according to the present embodiment includes a sensor unit 3 including a temperature detection element 2 that detects temperature, and a lead unit 4 that is conductively connected to the temperature detection element 2. The case 5 accommodates the sensor unit 3.
[0018]
The sensor unit 3 includes a temperature detection element 2 and, for example, an epoxy resin that covers and protects the periphery of the temperature detection element 2. As the temperature detection element 2, an element such as a thermistor or a temperature-sensitive semiconductor whose resistance value changes according to the temperature is used. In the present embodiment, for example, an NTC thermistor having a negative temperature coefficient is used. The temperature detection element 2 is conductively connected to a lead wire (not shown), and the resistance value of the temperature detection element 2 is shown as an electrical signal through the lead portion 4 communicating with the lead wire. Is not output to the control unit. As a result, the compressor (not shown) is controlled, and the amount of refrigerant that is pumped from the compressor to the evaporator (not shown) is adjusted, thereby adjusting the heat exchange amount (cooling degree) of air in the evaporator.
[0019]
The sensor unit 3 is housed in a case 5 made of a metal having excellent conductivity, such as Al or Cu. The case 5 has, for example, an opening 5b for inserting the sensor unit 3 at one end of the cylindrical part 5a, and is connected to the cylindrical part 5a at the other end, and the other end of the contact part with the cylindrical part 5a is closed. And an extended portion 5d that is communicated with the throttle portion 5c, has an angle of approximately 90 degrees with respect to the longitudinal direction of the case 5, and is formed integrally with the case 5. . FIG. 1B is a perspective view thereof. The extending portion 5d is flattened, for example, by press working, and will be described later in detail, but is formed smaller than the air passage between the fins of the evaporator.
[0020]
The inner wall of the case 5 is in contact with at least a part of the sensor unit 3, and the sensor unit 3 is protected, fixed, and cased in a gap between the case 5 and the sensor unit 3 other than the contact portion. In order to improve the thermal conductivity from 5 to the sensor unit 3, for example, a sealing resin 6 such as an epoxy resin is filled. In the present embodiment, the shape of the case 5 is an example of the cylindrical portion 5a. However, the sensor portion 3 can be accommodated in the case 5, and preferably, the inner wall thereof is at least part of the sensor portion 3. It only needs to have a shape that can be contacted. FIG. 1A shows an example in which up to a part of the lead part 4 connected to the sensor part 3 is housed in the case 5, but at least the place where the temperature detection element 2 of the sensor part 3 is arranged is shown. It only has to be stored in the case 5. However, when the entire sensor unit 3 is housed in the case 5, the temperature distribution difference in the sensor unit 3 can be reduced, and the temperature detection accuracy can be further improved.
[0021]
Next, FIG. 2 shows a schematic diagram when the evaporator temperature sensor 1 having the above structure is installed in the evaporator of the air conditioner. 2A is an enlarged plan view seen from the leeward side of the evaporator, and FIG. 2B is a cross-sectional view taken along the line AA of FIG.
[0022]
As shown in FIG. 2A, the evaporator 7 includes a plurality of refrigerant passage plates 8 and, for example, bellows-like fins 9 disposed between the refrigerant passage plates 8. When the air passes between the fins 9 and the air passage 10 including the refrigerant passage plate 8, the air comes into contact with the fins 9 and the refrigerant passage plate 8 and heat is taken away so that the air is cooled. The Then, the extending portion 5 d of the evaporator temperature sensor 1 is inserted into the air passage 10 from the wind surface side of the evaporator 7. In addition, since the said extension part 5d is formed smaller than the air path 10 previously, it can insert easily, without damaging the fin 9 and the plate 8 for refrigerant paths.
[0023]
At this time, as shown in FIG. 2 (b), the temperature detecting sensor 1 for the evaporator is such that the extending portion 5d inserted into the air passage 10 contacts the fin 9 (in FIG. 2 (b), the extending portion 5d (The lower surface is in contact with the fins 9). That is, the heat of the fin 9 is transmitted from the case 5 to the temperature detection element 2 of the sensor unit 3 through the extending portion 5d. Therefore, the temperature detection element 2 in the present embodiment can detect the temperature of the air after heat exchange in the evaporator 7 and can detect the temperature of the fin 9 itself via the extending portion 5d. The temperature can be detected with higher accuracy in order to prevent the fin 9 from freezing.
[0024]
In the present embodiment, the extending portion 5 d of the evaporator temperature sensor 1 is bent so as to have an angle of approximately 90 degrees with respect to the longitudinal direction of the case 5. When the extending portion 5 d is inserted into the air passage 10 between the fins 9 of the evaporator 7, a part of the cylindrical portion 5 a of the case 5 of the evaporator temperature sensor 1 is disposed so as to contact the end of the fin 9. can do. Therefore, the heat of the fin 9 of the evaporator 7 is transmitted to the temperature detection element 2 of the sensor unit 3 even through the cylindrical part 5a of the case 5, and the heat transfer path from the fin 9 to the temperature detection element 2 increases. Therefore, the temperature of the fin 9 can be detected by the temperature detection element 2 with higher accuracy. Further, since the two points of the extending portion 5d and the cylindrical portion 5a of the evaporator temperature sensor 1 are in contact with the fin 9 of the evaporator 7 at an angle of approximately 90 degrees, the evaporator temperature sensor 1 is more stably attached to the evaporator 7. Can be fixed.
[0025]
Further, when the extending portion 5 d is bent at an angle of approximately 90 degrees with respect to the case 5, the longitudinal direction of the evaporator temperature sensor 1 other than the extending portion 5 d is substantially parallel to the wind surface of the evaporator 7. Be placed. Therefore, the evaporator temperature sensor 1 does not protrude significantly in the direction perpendicular to the wind surface of the evaporator 7, and the arrangement space can be reduced.
[0026]
Further, the location of the evaporator temperature sensor 1 in the evaporator 7 is determined after performing a bench test that changes the outside air temperature, humidity, and the like. The evaporator temperature sensor 1 according to the present embodiment includes an extending portion 5 d integrated with the case 5. Since this extending portion 5 d is smaller than the air passage 10 between the fins 9 of the evaporator 7, it can be easily inserted between the fins 9 of the evaporator 7. Therefore, since positioning can be performed freely, it is suitable for changing the location of the evaporator 7 at the time of the bench test and for the location after the bench test.
[0027]
As shown in FIG. 3, a wedge-shaped protrusion 11 may be provided on the extending portion 5 d of the case 5 as a means for preventing the falling from the evaporator 7. The protruding portion 11 is formed at least on the contact surface side with the fin 9 in the extending portion 5d. The shape of the arrow shown in FIG. 3 is the direction in which the evaporator 7 is inserted into the air passage 10, and the opposite direction of the arrow, that is, the direction in which the extending portion 5 d is pulled out from the air passage 10, It is preferable to form in such a shape that the friction between the fin 9 and the protrusion 11 is increased. In this way, by forming the protrusion 11 on the extending portion 5d as a drop-off preventing means, the evaporator temperature sensor 1 is prevented from falling off from the evaporator 7, and there is no need to separately provide a fixing jig such as a clip. Therefore, the number of parts can be reduced.
[0028]
The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made.
[0029]
In the present embodiment, the case has the throttle portion between the cylindrical portion and the extending portion, but it is not always necessary to have the throttle portion. Moreover, in this Embodiment, although the extension part was provided in the other end with respect to the opening end of a case, you may provide an extension part on the surface of a cylindrical part.
[0030]
In the present embodiment, the example in which the angle of the extending portion of the case is bent at approximately 90 degrees with respect to the longitudinal direction of the case has been described, but is not limited to approximately 90 degrees. Therefore, the extending part may be formed along the longitudinal direction of the case.
[0031]
Further, in the present embodiment, an example in which the shape of the extending portion of the case is flat has been shown, but it is smaller than the air passage between the fins of the evaporator, and at least a part of the shape can be in contact with the fin. It ’s fine.
[0032]
Further, in the present embodiment, an example has been shown in which two portions of the extended portion and the cylindrical portion bent at approximately 90 degrees are brought into contact with the fins of the evaporator, but only the extended portion may be brought into contact with the fins. Needless to say. However, as the distance between the fins and the cylindrical part increases, the temperature measurement error increases due to the influence of the wind. It is preferable to arrange them so that the heat conduction efficiency is good.
[0033]
Moreover, in this Embodiment, the example which uses a metal for a case was shown. However, the case may be formed using a material such as a resin other than metal.
[Brief description of the drawings]
1A and 1B show an evaporator temperature detection sensor according to a first embodiment of the present invention, in which FIG. 1A is a cross-sectional view and FIG. 1B is a perspective view.
FIGS. 2A and 2B are diagrams for explaining the installation of an evaporator temperature detection sensor on an evaporator, FIG. 2A is a plan view, and FIG. 2B is a cross-sectional view taken along a line AA in FIG.
FIG. 3 is a cross-sectional view showing a modification of an evaporator temperature detection sensor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Evaporator temperature detection sensor, 2 ... Temperature detection element, 3 ... Sensor part, 5 ... Case, 5d ... Extension part, 7 ... Evaporator, 9 ... Fin 10 ... Air passage

Claims (5)

A temperature sensor for a heat exchanger, comprising: a sensor unit including a temperature detection element; a lead part electrically connected to the temperature detection element; and a case for housing the sensor part,
The case is smaller than the air passage between the storage portion for storing the sensor portion and the fins of the heat exchanger, and is integrated with the storage portion at an angle of approximately 90 degrees with respect to the longitudinal direction of the storage portion. Having a formed extension,
The extension part is in contact with the fin while being inserted into the air passage , and a part of the storage part is in contact with an end surface of the fin . The temperature sensor for a heat exchanger according to claim 1, wherein at least a part of the sensor unit is in contact with an inner wall of the storage unit in the case. The temperature sensor for a heat exchanger according to claim 1 or 2, wherein a gap between the sensor part and an inner wall of the storage part in the case is filled with resin.   The temperature sensor for a heat exchanger according to any one of claims 1 to 3, wherein the case is made of metal. The temperature sensor for a heat exchanger according to any one of claims 1 to 4 , wherein the extension part includes a drop-off prevention unit on at least a surface that contacts the fin .

Images