Air conditioner

Abstract

To provide an air conditioner in which a heat-sensitive pipe can be easily attached to refrigerant piping.SOLUTION: An air conditioner comprises: refrigerant piping 13 which constitutes a part of a refrigerant channel of a heat exchanger or constitutes piping connected to the heat exchanger, and which uses aluminum or an aluminum alloy as a material; a temperature sensor 15 that detects a temperature of the refrigerant piping 13; and a heat-sensitive pipe 14 for attaching the temperature sensor 15 to the refrigerant piping 13. The heat-sensitive pipe 14 has a brazed stationary part of a contact part between the refrigerant piping 13 and the heat-sensitive pipe 14, and an unbrazed unstationary part 22.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an air conditioner. [Background technology]

[0002] In controlling the refrigeration cycle of the heat pump system, it is necessary to detect the temperature of the heat exchanger. Japanese Patent No. 6822547 (Patent Document 1) is a background art in this technical field. This publication describes a heat exchanger (10) comprising: an aluminum pipe (30) through which a refrigerant flows; a thermistor (12) for detecting the temperature of the refrigerant; and an attachment portion (13) for attaching the thermistor (12) to the pipe (30), wherein a sacrificial layer (14) having a lower potential than the aluminum constituting the pipe (30) is provided on a portion of the surface of the pipe (30), the attachment portion (13) having a higher potential than the sacrificial layer (14), at least a portion of the attachment portion (13) is attached to a surface of the pipe (30) not provided with the sacrificial layer (14), the attachment portion (13) has a brazed portion (132) having a higher potential than the sacrificial layer (14), and the thermistor (12) is attached to the pipe (30) via the brazed portion (132) (see claims). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6822547 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of Patent Document 1, the refrigerant pipe is made of copper, and the thermistor is attached to the refrigerant pipe using a stainless steel C-shaped leaf spring. However, if the refrigerant pipe is made of aluminum or an aluminum alloy, the refrigerant pipe is likely to be damaged when the leaf spring is used, and corrosion is likely to occur due to contact between dissimilar metals, which can lead to problems such as refrigerant leakage from the refrigerant pipe or thermistor detachment. On the other hand, when brazing a heat-sensitive tube to a refrigerant pipe, the melting points of the brazing material and aluminum are close, making the installation difficult.

[0005] Therefore, an object of the present invention is to provide an air conditioner in which a heat-sensitive tube can be easily attached to a refrigerant pipe. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides an air conditioner having a heat exchanger, comprising refrigerant piping made of aluminum or an aluminum alloy, which forms part of the refrigerant flow path of the heat exchanger or which forms piping connected to the heat exchanger, a temperature sensor which detects the temperature of the refrigerant piping, and a heat-sensitive tube which attaches the temperature sensor to the refrigerant piping, wherein the heat-sensitive tube has a brazed fixed portion and an unbrazed non-fixed portion at the contact point between the refrigerant piping and the heat-sensitive tube. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an air conditioner in which a heat-sensitive tube can be easily attached to a refrigerant pipe. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of an air conditioner according to an embodiment of the present invention. [Figure 2] FIG. 2 is a front view of a heat exchanger in the air conditioner of the present embodiment. [Figure 3] 3 is a vertical cross-sectional view of a refrigerant pipe and a heat-sensitive tube in the air conditioner of the present embodiment. FIG. [Figure 4]FIG. 2 is a front view illustrating the joining state of the refrigerant pipe and the heat-sensing tube in the air conditioner of the present embodiment. [Figure 5] FIG. 10 is a front view illustrating another example of the joining state of the refrigerant pipe and the heat-sensing tube in the air conditioner of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 is a schematic diagram of an air conditioner 100 according to the present embodiment. The air conditioner 100 according to the present embodiment comprises an outdoor unit 1 and an indoor unit 2. The outdoor unit 1 includes a compressor 3 that compresses the refrigerant, a four-way valve 4 that switches the direction of the refrigerant flow, an outdoor heat exchanger 5 that exchanges heat between the outdoor air and the refrigerant, a propeller fan 6 that takes the outdoor air into the outdoor unit 1, and an expansion valve 7 that expands the refrigerant.

[0010] The indoor unit 2 is provided with an indoor heat exchanger 8 that exchanges heat between the indoor air and the refrigerant, and a cross-flow fan 9 that serves as a blower fan that takes the indoor air into the indoor unit 2. In the outdoor unit 1, the compressor 3, four-way valve 4, outdoor heat exchanger 5, expansion valve 7, and indoor heat exchanger 8 are connected by piping 10, and a refrigerant can circulate through each device via the piping 10. As the refrigerant, refrigerants such as R410A and R32 can be used. When the air conditioner 100 is in cooling operation, the four-way valve 4 is connected as shown by the solid lines in Fig. 1. In this case, the refrigerant discharged from the compressor 3 flows through the outdoor heat exchanger 5, the expansion valve 7, and the indoor heat exchanger 8 in this order, before circulating back to the compressor 3 (see the solid arrows in Fig. 1). On the other hand, when the air conditioner 100 is in heating operation, the four-way valve 4 is connected as shown by the dashed lines in Fig. 1. In this case, the refrigerant discharged from the compressor 3 flows through the indoor heat exchanger 8, the expansion valve 7, and the outdoor heat exchanger 5 in this order, before circulating back to the compressor 3 (see the dashed arrows in Fig. 1).

[0011] Inside the outdoor unit 1, outdoor air is drawn in by a propeller fan 6 and passes through an outdoor heat exchanger 5, thereby exchanging heat between the outdoor air and the refrigerant. Inside the indoor unit 2, indoor air is drawn in by a cross-flow fan 9 and passes through an indoor heat exchanger 8, thereby exchanging heat between the indoor air and the refrigerant. The air conditioner 100 then blows out conditioned air, which is indoor air that has been heated or cooled by exchanging heat with the refrigerant, to condition the room.

[0012] Fig. 2 is a plan view of the indoor heat exchanger. The indoor heat exchanger 8 (which may be the outdoor heat exchanger 5) includes a refrigerant pipe 11 through which a refrigerant flows and a plurality of fins 12 attached to the refrigerant pipe 11. Note that a large number of fins 12 are attached to the refrigerant pipe 11 in parallel in the horizontal direction with the length direction as the up-down direction, but Fig. 2 shows only some of them for convenience. The refrigerant pipe 11 is bent up and down at the left and right ends, so that a plurality of tubes are lined up above and below in a zigzag pattern. The refrigerant pipe 13 is a pipe that connects the refrigerant pipe 11 and the pipe 10. The refrigerant pipes 11 and 13 are made of aluminum or an aluminum alloy.

[0013] A heat-sensitive tube 14 is attached to the refrigerant pipe 13 (which may be the refrigerant pipe 11 that forms part of the refrigerant flow path of the indoor heat exchanger 8). A temperature sensor 15 (FIG. 3) (a thermistor in this example) is attached inside the heat-sensitive tube 14. The temperature sensor 15 is a sensor that detects the temperature of the refrigerant pipe 13. A wire 31 is a wire that connects the temperature sensor 15 to a predetermined circuit board (not shown). The wire 31 is connected from the lower end of the heat-sensitive tube 14 to the temperature sensor 15. The heat-sensitive tube 14 is made of aluminum or an aluminum alloy.

[0014] FIG. 3 is an enlarged longitudinal cross-sectional view of the refrigerant pipe and the heat-sensing tube. As described below, the heat-sensing tube 14 is brazed to the side of the refrigerant pipe 13, where the longitudinal direction of the refrigerant pipe 13 extends vertically and linearly, with its length parallel to the longitudinal direction of the refrigerant pipe 13. The heat-sensing tube 14 is a hollow container with upper and lower ends opening to the outside from the hollow portion 14a. One of the upper and lower ends of the heat-sensing tube 14 may be closed. Generally, it is easier to manufacture the heat-sensing tube 14 by making it a tube with a uniform cross-sectional size and shape at any position along its length. The diameter of the tube 14 may be circular or polygonal. However, the size and shape of the hollow portion 14a must be such that the temperature sensor 15 can be easily inserted through the opening 14b. In this embodiment, the temperature sensor 15 is inserted through the lower opening 14b. The temperature sensor 15 is biased within the hollow portion 14a by an elastic member such as a leaf spring 16, and is pressed against the inner circumferential surface of the hollow portion 14a on the refrigerant pipe 13 side, preventing it from falling out of the heat-sensing tube 14. The upper end 16a of the leaf spring 16 is bent into a U-shape and engages with the upper opening 14b to prevent it from falling out. The lower end 16b of the leaf spring 16 is bent into a hook shape and is engaged with the lower opening 14b.

[0015] 4 and 5 are front views of the refrigerant pipe and the heat-sensing tube. The refrigerant pipe 13 and the heat-sensing tube 14 are joined by brazing in region 21. The brazing material used is preferably an aluminum alloy such as A4047 (aluminum-silicon alloy) that has a lower melting point than the aluminum material constituting the refrigerant pipe 13. In other words, the brazing material is preferably an aluminum alloy of a different type from the material used in the refrigerant pipe 13, and has a lower melting point than the material used in the refrigerant pipe 13. In addition, to prevent the thermal effects of brazing from affecting the temperature sensor 15, it is preferable to attach the temperature sensor 15 inside the heat-sensing tube 14 after brazing the heat-sensing tube 14.

[0016] 4 and 5, the heat-sensitive tube 14 is in contact with the side of the refrigerant pipe 13 from the upper end to the lower end in the longitudinal direction. Only a region 21, which is a part of the contact portion in the vertical direction, is brazed. Furthermore, the brazing may result in a small gap between the refrigerant pipe 13 and the heat-sensing tube 14. In the example of Figure 3, a small gap is shown between the refrigerant pipe 13 and the heat-sensing tube 14.

[0017] 3 to 5, the heat-sensitive tube 14 faces the refrigerant pipe 13 horizontally from its upper end to its lower end in the longitudinal direction (including the case where the heat-sensitive tube 14 and the refrigerant pipe 13 are in contact with each other). The brazed region 21 is the fixed portion where the heat-sensitive tube 14 is fixed to the refrigerant pipe 13.

[0018] The heat-sensitive tube 14 has an unbrazed portion (a portion other than the region 21) on at least one side in the direction (longitudinal direction). In the example of Fig. 5, at least one of the upper and lower portions of the region 21 (both in Fig. 5) is an unbrazed unfixed portion 22. In the example of Fig. 3, the heat-sensitive tube 14 has an unbrazed unfixed portion that is the same distance from the refrigerant pipe 13 as the brazed portion, as in the case of Fig. 5.

[0019] 4, the heat-sensitive tube 14 is brazed at a position corresponding to the surface (outer surface) of the temperature sensor 15 where the temperature detection portion 15a of the temperature sensor 15 is located when the temperature sensor 15 is attached. If the temperature sensor 15 is a thermistor, the temperature detection portion 15a is a semiconductor element that detects temperature. The heat-sensing tube 14 has one (the lower one in the example of FIG. 5) of the non-brazed portions (non-fixed portion 22 in the example of FIG. 5) at both ends in the longitudinal direction that are not brazed longer than the other. In the longitudinal direction of the heat-sensing tube 14, the fixed portion (region 21) is shorter than the temperature sensor 15 (FIG. 4). In the longitudinal direction of the heat-sensing tube 14, the fixed portion (region 21) is shorter than the non-fixed portion 22 (FIG. 5). In the longitudinal direction of the heat-sensing tube 14, the fixed portion (region 21) is longer than the temperature detection portion 15a of the temperature sensor 15. It is preferable that the wall thickness of the heat-sensing tube 14 is thicker than the wall thickness of the refrigerant pipe 13 (not shown).

[0020] Refrigerant pipe 13 has straight pipe and bent pipe (Fig. 2), and fixed portion (region 21) and non-fixed portion 22 are located at positions corresponding to the straight pipe (Figs. 3 to 5). The air conditioner 100 may be configured as follows. That is, the air conditioner 100 is equipped with an indoor unit 2 and an outdoor unit 1, but the heat exchanger is an indoor heat exchanger 8. That is, the heat-sensitive tube 14 attached to the refrigerant piping 13 arranged in the indoor unit 2 has a fixed portion (region 21) and a non-fixed portion 22. The heat-sensitive tube 14 attached to the refrigerant piping 13 arranged in the outdoor unit 1 has only the fixed portion (region 21) and does not have the non-fixed portion 22.

[0021] Next, the effects of this embodiment will be described. In this embodiment, brazing is used to join the refrigerant pipe 13 and the heat-sensing tube 14, and plate springs or the like are not used as in Patent Document 1, so the aluminum refrigerant pipe 13 is less likely to be damaged. Also, because both the refrigerant pipe 13 and the heat-sensing tube 14 are made of aluminum, corrosion due to contact between dissimilar metals is less likely to occur. This makes it less likely that refrigerant will leak from the refrigerant pipe 13 or that the temperature sensor 15 will fall off. This makes it possible to provide an air conditioner 100 in which the heat-sensing tube 14 can be easily attached to the refrigerant pipe 13.

[0022] Furthermore, since the brazing of the refrigerant pipe 13 and the heat-sensitive tube 14 is performed only partially, rather than entirely, as described above, the joining work of the refrigerant pipe 13 and the heat-sensitive tube 14 can be completed in a short time, and the refrigerant pipe 13 and the heat-sensitive tube 14 are less likely to be damaged. This increases the productivity of the air conditioner 100. At least one of the upper and lower ends of the heat-sensitive tube 14, in this example both, has an unbrazed portion. These ends are difficult to braze, and if brazing is attempted, the brazing material is likely to find its way inside the heat-sensitive tube 14. Therefore, by leaving at least one of the upper and lower ends of the heat-sensitive tube 14 unbrazed, the brazing work can be completed in a short time, and since the brazing material does not find its way inside the heat-sensitive tube 14, it is possible to easily store the temperature sensor 15 inside the heat-sensitive tube 14.

[0023] The heat-sensitive tube 14 is brazed at a position corresponding to the outer surface of the temperature sensor 15 where the temperature detection portion 15a of the temperature sensor 15 is located when the temperature sensor 15 is attached, thereby improving the accuracy of temperature detection by the temperature sensor 15. The heat-sensitive tube 14 has one of the non-brazed portions (non-fixed portions 22 in the example of FIG. 5) at both ends in the longitudinal direction that is longer than the other (the lower non-fixed portion 22 in the example of FIG. 5). In this embodiment, the temperature sensor 15 is inserted from the lower side of the heat-sensitive tube 14. This prevents the lower side of the heat-sensitive tube 14 from being thermally deformed by the brazing operation, making it difficult to insert the temperature sensor 15 from the lower side of the heat-sensitive tube 14.

[0024] In the longitudinal direction of the heat-sensing tube 14, the fixed portion (region 21) is shorter than the temperature sensor 15 (FIG. 4). Also, in the longitudinal direction of the heat-sensing tube 14, the fixed portion (region 21) is shorter than the non-fixed portion 22 (FIG. 5). Therefore, the range of the fixed portion (region 21) is limited, improving the workability of the brazing work. In the longitudinal direction of the heat-sensitive tube 14, the fixed portion (region 21) is longer than the temperature detection portion 15a of the temperature sensor 15. Therefore, the temperature on the refrigerant pipe 13 side is sufficiently transmitted to the temperature detection portion 15a via the fixed portion (region 21), ensuring the detection accuracy of the temperature sensor 15.

[0025] The thickness of the heat-sensitive tube 14 is preferably thicker than the thickness of the refrigerant pipe 13 (not shown), which makes it difficult for the heat-sensitive tube 14 to melt during brazing work. The brazing material used for brazing the fixed portion (region 21) is an aluminum alloy of a different type from the material used for the refrigerant pipe 13, and preferably has a melting point lower than that of the material used for the refrigerant pipe 13. In this way, an aluminum alloy is also used for the brazing material, which suppresses sacrificial corrosion protection, and by using different types of alloy for the brazing material and the refrigerant pipe 13, the melting point of the brazing material can be lowered, making it difficult for the refrigerant pipe 13 to melt during the brazing work.

[0026] Furthermore, if the heat-sensitive tube 14 attached to the refrigerant piping 13 arranged in the indoor unit 2 has a fixed portion (region 21) and a non-fixed portion 22, and the heat-sensitive tube 14 attached to the refrigerant piping 13 arranged in the outdoor unit 1 has only the fixed portion (region 21) and does not have the non-fixed portion 22, the following effects can be achieved. That is, the possibility of the heat-sensitive tube 14 coming off due to corrosion is higher in the outdoor unit 1 than in the outdoor unit 2. Therefore, by making the refrigerant piping 13 arranged in the outdoor unit 1 have only the fixed portion (region 21) and not the non-fixed portion 22, it becomes possible to braze the entire heat-sensitive tube 14 to the refrigerant piping 13, and the possibility of the heat-sensitive tube 14 coming off due to corrosion can be reduced.

[0027] It should be noted that the present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to an embodiment having all of the described configurations. [Explanation of symbols]

[0028] 1 Outdoor unit 2 Indoor unit 5 Indoor heat exchanger (heat exchanger) 8 Outdoor heat exchanger (heat exchanger) 11 Refrigerant piping (piping) 13 Refrigerant piping (piping) 14 Heat sensitive tube 15 Temperature Sensor 15a Temperature detection unit 21 area (fixed part) 22 Non-fixed part 31 Wiring 100 Air conditioner

Claims

1. An air conditioner having a heat exchanger, a refrigerant pipe made of aluminum or an aluminum alloy, which constitutes a part of a refrigerant flow path of the heat exchanger or constitutes a pipe connected to the heat exchanger; a temperature sensor for detecting the temperature of the refrigerant pipe; a heat-sensitive tube for attaching the temperature sensor to the refrigerant pipe; The heat-sensitive tube has a brazed fixed portion and an unbrazed non-fixed portion at the contact portion between the refrigerant pipe and the heat-sensitive tube.

2. An air conditioner having a heat exchanger, a refrigerant pipe made of aluminum or an aluminum alloy, which constitutes a part of a refrigerant flow path of the heat exchanger or constitutes a pipe connected to the heat exchanger; a temperature sensor for detecting the temperature of the refrigerant pipe; a heat-sensitive tube for attaching the temperature sensor to the refrigerant pipe; The heat-sensitive tube is a fixed portion fixed to the refrigerant pipe by brazing; an unfixed portion that is not brazed and is spaced apart from the refrigerant pipe by the same distance as the distance between the fixed portion and the refrigerant pipe.

3. The air conditioner according to claim 1 or 2, wherein the heat-sensitive tube has the non-fixed portion on at least one of both ends in a direction.

4. The air conditioner according to claim 1 or 2, wherein the heat-sensitive tube has the fixed portion at a position corresponding to an outer surface of a portion where a temperature detecting portion of the temperature sensor is located when the temperature sensor is attached.

5. a wiring for connecting the temperature sensor to a circuit board; The wiring is connected from the lower end of the heat-sensitive tube to the temperature sensor, The air conditioner according to claim 4, wherein the heat-sensitive tube has the non-fixed portion at both ends in the longitudinal direction, and the non-fixed portion located at the upper end is longer than the non-fixed portion located at the lower end.

6. 3. The air conditioner according to claim 1, wherein the fixed portion is shorter than the temperature sensor in the longitudinal direction of the heat-sensitive tube.

7. The air conditioner according to claim 1 or 2, wherein the fixed portion is shorter than the non-fixed portion in the longitudinal direction of the heat-sensitive tube.

8. 3. The air conditioner according to claim 1, wherein the fixed portion is longer than the temperature detecting portion of the temperature sensor in the longitudinal direction of the heat-sensitive tube.

9. 3. The air conditioner according to claim 1, wherein the heat-sensitive tube is made of aluminum or an aluminum alloy.

10. The air conditioner according to claim 9, wherein the heat-sensitive tube has a wall thickness greater than that of the refrigerant pipe.

11. The refrigerant pipe has a straight pipe and a bent pipe, The air conditioner according to claim 1 or 2, wherein the fixed portion and the non-fixed portion are located at positions corresponding to the straight pipe.

12. 3. The air conditioner according to claim 1, wherein the brazing material used for brazing the fixed portion is an aluminum alloy of a different type from the material used for the refrigerant piping, and has a melting point lower than that of the material used for the refrigerant piping.

13. Equipped with an indoor unit and an outdoor unit, the heat exchanger is an indoor heat exchanger, the heat-sensing tube attached to the refrigerant pipe arranged in the indoor unit has the fixed portion and the non-fixed portion, 3. The air conditioner according to claim 1, wherein the heat-sensitive tube attached to the refrigerant pipe arranged in the outdoor unit has only the fixed portion and does not have the non-fixed portion.

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