JP2014061810A - Heat pump-type cooling and heating air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat pump-type cooling and heating air conditioner excellent in durability.SOLUTION: Characteristically, a heat pump-type cooling and heating air conditioner includes heat medium piping 1 having a joint 4 formed by brazing, and a waterproof film 5 made of a silicone resin with a thickness of 1.0 mm or more is formed on a surface 400 of a fillet 40 formed in the joint 4. Preferably, the heat medium piping 1 is made of aluminum or an aluminum alloy. Preferably, a linear expansion coefficient of the silicone resin is in the range of 20×10to 100×10/K.

Description

  The present invention relates to a heat pump type air conditioning air conditioner.

  2. Description of the Related Art In recent years, heat pump air-conditioning air conditioners that are easy to save energy have been adopted as air conditioners installed in automobiles. The heat pump type air conditioning air conditioner is configured by connecting devices such as a heat exchanger (evaporator and condenser), a compressor, and an expansion valve to each other through a heat medium pipe.

  While the air conditioner is in operation, for example, the periphery of the evaporator is at a low temperature because it is absorbed by the heat medium. For this reason, moisture in the air may condense on the outer wall of the heat medium pipe, or the condensed moisture may freeze.

  By the way, there is one in which the connection between the heat medium pipe and each device and the connection between the heat medium pipes are performed by brazing. A void may be formed in the fillet of the joint portion by brazing. When the above-mentioned water enters the void, the water may repeat freezing and thawing according to changes in the operating state of the air conditioner. As a result, the voids are subjected to stress due to repeated expansion and contraction of moisture, and the fillet may be deteriorated.

  Therefore, as a method for preventing the deterioration of the fillet, Patent Document 1 discloses a method of applying a silicone rubber liquid to the surface of the fillet at the joint portion by brazing. In the invention disclosed in Patent Document 1, a silicone rubber coating film is formed on the fillet surface of the torch brazing portion of the evaporator, and the void formed on the fillet is closed with the silicone rubber coating film. Thereby, it is intended to prevent moisture from condensing inside the void.

JP 2000-158177 A

  However, the application of the silicone rubber coating described in Patent Document 1 to a fillet of a heat medium pipe in a heat pump type air conditioner has the following problems. The heat pump air-conditioning / air-conditioning apparatus is configured such that the evaporator and the condenser are switched during the cooling operation and the heating operation. That is, for example, a heat exchanger that functions as an evaporator during cooling operation is configured to function as a condenser during heating operation. Therefore, the temperature of the heat medium flowing through the heat medium pipe varies in a wide range from a low temperature to a high temperature.

  Therefore, the silicone rubber coating film formed with a thin film thickness of 10 to 70 μm as in Patent Document 1 cannot follow the expansion and contraction of the fillet due to the temperature change of the heating medium, and the silicone rubber coating film is broken or peeled off. Etc. may occur.

  The present invention has been made in view of the above background, and an object of the present invention is to provide a heat pump air-conditioning / air-conditioning apparatus having excellent durability.

One aspect of the present invention includes a heat medium pipe having a joint by brazing,
The heat pump air-conditioning / air-conditioning apparatus is characterized in that a waterproof film made of a silicone resin having a thickness of 1.0 mm or more is formed on the surface of the fillet formed at the joint.

  In the heat pump type air conditioning air conditioner, a waterproof film made of a silicone resin having a thickness of 1.0 mm or more is formed on the surface of the fillet. Therefore, even when a void is formed in the fillet, the waterproof film can prevent moisture from entering the void. As a result, it is possible to prevent the joint from deteriorating from the void.

  Moreover, since the said waterproof film is formed in the thickness of 1.0 mm or more, it becomes a sufficiently high intensity | strength. Therefore, the waterproof membrane is less likely to break or peel off when the fillet expands or contracts as the temperature of the heat medium changes, and has excellent durability. As a result, the durability of the fillet can be improved, and the durability of the heat pump type air conditioner can be improved.

  As mentioned above, according to the said aspect, the heat pump type air conditioning air conditioner excellent in durability can be provided.

The perspective view of the heat-medium piping in an Example. The perspective view of the service valve of heat-medium piping in an Example. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is a sectional view taken along line IV-IV in FIG. 2. The perspective view of the branch pipe of a heat-medium piping in an Example. The perspective view of the connection adapter of a heat medium piping in an Example.

  In the heat pump type air conditioner, the thickness of the waterproof film is 1.0 mm or more, preferably 1.5 mm or more. As the film thickness increases, the waterproof film is less likely to be broken or peeled off, and is excellent in durability. Although the upper limit of the film thickness of the waterproof film is not particularly limited, if the amount of the silicone resin applied is increased in order to increase the film thickness, the applied silicone resin hangs down by its own weight before curing, and the desired film thickness May not be obtained. The coating amount at which such a phenomenon occurs varies depending on the viscosity of the silicone resin used, and the larger the viscosity, the larger the coating amount.

  Moreover, as said silicone resin, what has favorable adhesiveness between the said junction parts can be used. As the silicone resin, various types such as RTV (Room Temperature Vulcanization) rubber, adhesive, sealant and the like can be adopted.

  The heating medium pipe is preferably made of aluminum or an aluminum alloy. In this case, it is easy to reduce the weight of the heat medium pipe.

The linear expansion coefficient of the silicone resin is preferably 20 × 10 ^{−6 to} 100 × 10 ⁻⁶ / K (Claim 3). In this case, the linear expansion coefficient of the silicone resin is relatively close to the linear expansion coefficient of aluminum or aluminum alloy. Therefore, it becomes easier to follow the expansion and contraction of the waterproof film with respect to the expansion and contraction of the joint portion accompanying the temperature change. As a result, the waterproof membrane becomes more difficult to break when the temperature of the joint portion changes, and the durability can be further improved.

  Moreover, the minimum temperature which the said junction part reaches | attains during use is lower than -20 degreeC, and the maximum temperature may exceed 80 degreeC (Claim 4). That is, since the waterproof membrane made of the silicone resin has excellent durability as described above, it can be suitably used in a wide temperature range. Therefore, the said junction part in which the said waterproofing membrane was formed can be used conveniently also when the lowest temperature in use is lower than -20 degreeC and the highest temperature exceeds 80 degreeC. In addition, although the minimum of the said minimum temperature is not specifically limited, The minimum value in normal use environment is -40 degreeC. Similarly, the upper limit of the maximum temperature is not particularly limited, but the upper limit in a normal use environment is 130 ° C.

(Example)
The Example of the said heat pump type | formula air conditioning air conditioner is demonstrated using FIGS. As shown in FIG. 1, the heat pump type air conditioning air conditioner includes a heat medium pipe 1 having a joint 4 by brazing. As shown in FIGS. 3 and 4, a waterproof film 5 made of a silicone resin having a thickness of 1.0 mm or more is formed on the surface 400 of the fillet 40 formed in the joint portion 4.

  As shown in FIG. 1, the heat medium pipe 1 includes a main pipe 10, a service valve 2, a branch pipe 11, and a connection adapter 3 joined to the main pipe 10 by brazing. The main pipe 10 is made of a round pipe made of aluminum alloy (A3003 material, outer diameter 1/2 inch), and is appropriately bent so as to be suitable for an arrangement space such as an engine room.

  The service valve 2 is a valve that functions as a lead-out port that supplies a heat medium into the air conditioner or discharges the heat medium in the air conditioner. The service valve 2 is made of age-hardened high-strength aluminum or aluminum alloy, and one end of the service valve 2 is inserted into a through hole 100 formed in the outer wall of the main pipe 10 as shown in FIGS. The service valve 2 and the main pipe 10 are brazed with a brazing material made of BA4047 material. As a result, as shown in FIGS. 3 and 4, a brazed joint 4 is formed at the base of the service valve 2, and the service valve 2 is substantially orthogonal to the axial direction of the main pipe 10 as shown in FIG. 2. Protrudes in the direction.

  As with the main pipe 10, the branch pipe 11 is formed by appropriately bending a 1/2 inch diameter round pipe made of A3003 material. As shown in FIGS. 1 and 5, the branch pipe 11 is arranged so that one end thereof is in contact with the outer wall surface of the main pipe 10, and a merging hole portion (not shown) formed through the outer wall surface. The heat medium is configured to be branched into the branch pipe 11.

  The opening end of the branch pipe 11 on the side in contact with the main pipe 10 is formed in a shape along the outer wall surface of the main pipe 10 and has a flare portion 110 shown in FIG. The flare portion 110 is formed to extend outward in the radial direction with the opening end of the branch pipe 11 as a base end. The flare portion 110 and the outer wall surface of the main pipe 10 are arranged so as to be in surface contact with each other, and are brazed to each other by a brazing material made of BA4047 material. Thereby, the junction part 4 by brazing is formed at the base of the branch pipe 11.

  The connection adapter 3 is made of age-hardened high-strength aluminum or aluminum alloy, and as shown in FIG. 6, a pipe insertion port 30 into which the opening end of the heat medium pipe 1 is inserted, and a heat medium conduction exhaust port such as a heat exchanger. And a fastening hole 32 into which a bolt for fastening the connection adapter 3 and the device is inserted. The connection adapter 3 is a device such as the heat medium pipe 1 and the heat exchanger connected to the pipe insertion port 30 by inserting the device connection portion 31 into the heat medium conduction outlet and being fastened to the heat exchanger or the like. The heat medium can be distributed between the two. In the connection adapter 3 of this example, the O-ring 310 is disposed on the outer peripheral portion of the device connecting portion 31, and the outer peripheral surface of the O-ring 310 is inserted when the device connecting portion 31 is inserted into the heat transfer port. Is in close contact with the inner peripheral surface of the heat medium conduction outlet, and is configured to prevent leakage of the heat medium.

  For example, as shown in FIGS. 1 and 6, the opening end of the main pipe 10 is inserted into the pipe insertion port 30 of the connection adapter 3. The pipe insertion port 30 and the main pipe 10 are brazed with a brazing material made of BA4047 material. Thereby, the joining part 4 by brazing is formed in the pipe insertion port 30.

  For example, as shown in FIGS. 3 and 4, a braze fillet 40 is formed in the joint portion 4 by brazing described above. A waterproof film 5 made of silicone resin is formed on the surface 400 of the fillet 40.

In this example, the waterproof membrane 5 has a thickness of 1.0 mm. The thickness of the waterproof membrane 5 is an average thickness of the entire waterproof membrane 5 that can be approximately calculated by the following formula (1). In the following formula (1), t (mm) is the thickness of the waterproof film 5, m (g) is the weight of the applied waterproof film 5, and d (g / cm ³ ) is the density of the waterproof film 5. It is. W (cm) is the application width of the waterproof film 5. L (cm) is the application length of the waterproof film 5.

          t = m / (d × W × L) × 10 (1)

  Therefore, the thickness t of the waterproof film 5 can be managed by managing the values of the weight m, the density d, the coating width W, and the coating length L of the waterproof film 5 based on the above formula (1). . In addition, the value calculated by an appropriate method according to the shape of the fillet 40 can be used as the value of the coating width W and the coating length L. For example, in the case of the fillet 40 formed at the base of the service valve 2, the coating width W is a value obtained by averaging the width x on the surface 500 of the waterproof film 5 shown in FIGS. 3 and 4 over the entire waterproof film 5. Can do. As shown in FIG. 3, the coating length L can be the circumference length calculated from the outer diameter R of the portion of the service valve 2 that is inserted and arranged in the main pipe 10.

  Next, the effect of the heat pump type air conditioning air conditioner of this example will be described. In the heat pump air-conditioning / air conditioning apparatus, a waterproof film 5 made of a silicone resin having a thickness of 1.0 mm or more is formed on the surface 400 of the fillet 40 formed at the joint 4 of the heat medium pipe 1. Therefore, even when a void is formed in the fillet 40, the waterproof film 5 can prevent moisture from entering the void. As a result, it is possible to prevent the joint 4 from deteriorating from the void.

  Moreover, since the waterproof film 5 is formed with a thickness of 1.0 mm or more, it has a sufficiently high strength. Therefore, the waterproof membrane 5 is not easily broken when the joint portion 4 expands or contracts with a temperature change, and has excellent durability. As a result, the durability of the fillet 40 is improved, and the durability of the heat pump air-conditioning / air conditioning apparatus can be improved.

  The heat medium pipe 1 is made of aluminum or an aluminum alloy. Therefore, it becomes easy to reduce the weight of the heat medium pipe 1. When the heat pump air-conditioning / air-conditioning apparatus thus reduced in weight is mounted on, for example, an automobile, an effect of improving fuel efficiency can be expected.

  As described above, the heat pump type air conditioning air conditioner is excellent in durability.

(Experimental example)
This example is an example in which the material and thickness of the waterproof film in the heat pump air-conditioning and air-conditioning apparatus of the above-described embodiment were examined. In this example, a simulated sample simulating the peripheral part of the service valve in the above example was produced. Thereafter, waterproof membranes having various materials and thicknesses were formed on the fillets formed on the simulated sample, and various test specimens shown in Table 1 were produced. And the heat-and-heat durability test was done using each test body produced in this way, and the durability of a waterproof membrane was evaluated. Details of this experimental example will be described below.

<Simulated sample>
As described above, the simulated sample was prepared by simulating the service valve periphery in Example 1. That is, a through hole was formed in the outer wall of a 1/2 inch diameter round pipe made of A3003 material, and one end of the service valve used in the above example was inserted into the through hole. Thereafter, the round pipe and the base of the service valve were joined by brazing using a paste-like brazing material made of BA4047 material. As a result, a simulated sample having a fillet at the base of the service valve was obtained.

<Silicone resin>
As the silicone resin, the following two types of resins were used.

・ Resin A
Product name: SX720BH (Cemedine)
Main component: Acrylic modified silicone resin Density: 1.57 g / cm ³
Linear expansion coefficient: 81 × 10 ⁻⁶ / K
Viscosity before curing: 85 Pa · s

・ Resin B
Product name: SX720W (Cemedine)
Main component: Acrylic modified silicone resin Density: 1.56 g / cm ³
Linear expansion coefficient: 110 × 10 ⁻⁶ / K
Viscosity before curing: 45 Pa · s

  In addition, the said viscosity before hardening is a typical value of the viscosity measured at 23 degreeC.

  The above two types of silicone resins were applied to the surface of the fillet of the simulated sample with various application amounts, and then the silicone resin was cured to form a waterproof film. Thereby, as shown in Table 1, the test bodies (Test body 1 to Test body 32) in which the thickness of the waterproof film was changed to various values were obtained.

  The thickness of the waterproof film is a value calculated from the values of the weight m, the density d, the coating width W, and the coating length L of the waterproof film based on the above formula (1). As the calculation method of the coating width W and the coating length L, the method described in the above embodiment was used.

<Cooling durability test>
A cycle in which each specimen shown in Table 1 was placed in an atmosphere of −40 ° C. for 20 minutes and then placed in an atmosphere of 130 ° C. for 20 minutes was defined as one cycle, and this cycle was repeated 1500 times. And after completion | finish of the last cycle, each test body was left to stand in room temperature environment, and the temperature of the test body was returned to room temperature. Thereafter, the waterproof membrane was visually observed in a state where the temperature of the test body was returned to room temperature, and whether the waterproof membrane was broken or peeled off was confirmed. Table 1 shows the results of visual observation.

  As can be seen from Table 1, the test specimen having a waterproof film thickness of 1.0 mm or more is ruptured or peeled off by a thermal endurance test when either silicone resin A or resin B is used. Was not recognized.

  Further, the waterproof film made of resin A did not break after the cold endurance test even when the film thickness was 1.0 mm or less, whereas the waterproof film made of resin B might break after the cold endurance test. (Test body 31). That is, the waterproof film made of resin A may be more durable than the waterproof film made of resin B.

This is considered because the linear expansion coefficient of the resin A is in the range of 20 × 10 ^{−6 to} 100 × 10 ⁻⁶ / K. In other words, when the linear expansion coefficient of the silicone resin is within the above specific range, the linear expansion coefficient of the silicone resin is relatively close to the linear expansion coefficient of aluminum or aluminum alloy. This makes it easier to follow the expansion and contraction of the waterproof membrane with respect to the expansion and contraction. As a result, it is considered that the waterproof film is more difficult to break when the temperature of the joint changes, and the durability can be further improved.

  Moreover, the fillet in the simulation sample of this example had a minimum temperature of −40 ° C. and a maximum temperature of 130 ° C. in the cold endurance test. Therefore, the waterproof film formed as in this example can be suitably used in an environment where the minimum temperature reached during use is lower than −20 ° C. and the maximum temperature exceeds 80 ° C.

  In addition, the joint part by brazing is not limited to the connection part of the service valve, the branch pipe, the connection adapter, and the heat medium pipe shown in Example 1, and the joint part by brazing is formed in the heat medium pipe. If it is, the waterproof membrane can be applied.

DESCRIPTION OF SYMBOLS 1 Heat-medium piping 4 Junction part 40 Fillet 400 Surface 5 Waterproof membrane

Claims (4)

It has a heat medium pipe (1, 10, 11) having a joint (4) by brazing,
A heat pump type characterized in that a waterproof film (5) made of a silicone resin having a thickness of 1.0 mm or more is formed on the surface (400) of the fillet (40) formed in the joint (4). Air conditioning unit.   2. The heat pump air conditioner according to claim 1, wherein the heat medium pipe (1, 10, 11) is made of aluminum or an aluminum alloy. The heat pump air-conditioning / air-conditioning apparatus according to claim 2, wherein the silicone resin has a linear expansion coefficient of 20 × 10 ^{−6 to} 100 × 10 ⁻⁶ / K.   4. The heat pump air-conditioning / air-conditioning apparatus according to claim 1, wherein the joint (4) has a minimum temperature that is lower than −20 ° C. and a maximum temperature that exceeds 80 ° C. during use. The heat pump type air conditioning air conditioner characterized by this.

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