JPH09303905A - Insulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce passing sound of refrigerant and prevent dew formation by an insulator having a superior fixing workability. SOLUTION: This is an insulator which is inserted from outside into an outlet pipe in an expansion valve, wherein this is formed into a cylindrical shape in such a way that an outer circumferential part 112 shows a lower foaming efficiency than that of an inner circumferential part 11. With such an arrangement as above, it is possible to attain a higher sound-preventing effect by the outer circumferential part 12 having a higher specific weight than that of the inner circumferential part 11, resulting in that it is possible to prevent a dew formation at the surface of the outlet pipe by the inner circumferential part 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulator externally attached to a refrigerant pipe, and is particularly suitable for use in an air conditioning refrigeration cycle device.

[0002]

2. Description of the Related Art Conventionally, in an air conditioner constructed by sequentially connecting a compressor, a condenser, an expansion valve, and an evaporator, EPDM having a foaming ratio of about 5 is installed in a refrigerant pipe of the air conditioner.
By inserting a tubular insulator made of (ethylene propylene copolymer) foam, condensation on the surface of the refrigerant pipe is prevented and the refrigerant pipe is protected from external impact and static pressure such as assembly parts. There was something.

Further, the refrigerant pipe of the air conditioner is made of a mixture of hydrophobic urethane and bituminous foam (trade name: Super Seal A).
In some cases, the vibration noise of the refrigerant pipe is reduced by covering the two with a long plate member made of S Nippon Seijo Co., Ltd., in a middle position.

[0004]

By the way, in the pipe through which the refrigerant flows, this refrigerant hits the inner wall of the pipe, so that the pipe vibrates and is connected to the expansion valve due to vibration of the expansion valve during operation of the expansion valve. The piping vibrates. Then, the vibration sound of the refrigerant pipe is generated by the vibration of the pipe being spread in the air.

It is generally known that the heavier the soundproofing material, the more excellent the soundproofing effect is. The EPDM foam can be used as a soundproof material, but the cylindrical insulator for preventing dew condensation has a thin thickness of about 10 mm, and has a specific gravity (hereinafter referred to as a specific gravity) of about 0. Since it is as small as about 25, the vibration noise cannot be sufficiently reduced.

Further, the two long plate members for soundproofing are
Since it was necessary to attach it to the pipe with an adhesive, etc., the workability of mounting was poor. The present invention has been made in view of the above problems, and it is an object of the present invention to reduce vibration noise of a refrigerant pipe and prevent dew condensation by an insulator having a good mounting workability.

[0007]

In order to achieve the above object, in the invention described in claims 1 to 4, the refrigerant is externally inserted into the refrigerant pipe (52) through which the refrigerant is formed and is made of a single foamable material. Is an insulator, and the expansion ratio is
When expressed by the volume of the material after foaming / the volume of the material in an unfoamed state, the outer peripheral portion (12) has a lower foaming ratio than the inner peripheral portion (11), and is formed in a tubular shape. It is characterized by that.

According to this structure, the inner peripheral portion (11)
Has a high expansion ratio and contains a large amount of bubbles, so the specific gravity is small, and the outer peripheral part (12) has a low expansion ratio and contains a small amount of bubbles, and thus has a large specific gravity. Further, since the outer peripheral part (12) having a large specific gravity can obtain a high soundproofing effect, the vibration noise of the refrigerant pipe (52) can be reduced. Also,
The insulator (10) can be made thinner as compared with the case where the soundproofing effect is obtained only by the member having a high expansion ratio.

Also, since the insulator (10) can be attached to the refrigerant pipe (52) by a simple operation of externally inserting the tubular insulator (10) into the refrigerant pipe (52), an adhesive or the like can be used. Thus, the mounting workability can be improved as compared with the case where two long plate members are bonded together. Further, since the inner peripheral portion (11) containing a large amount of bubbles is relatively excellent in flexibility, the workability of attaching the insulator (10) can be further improved.

Further, since the insulator (10) is provided with the inner peripheral portion (11) containing a large amount of bubbles, the insulator (10) has poor thermal conductivity, and the refrigerant pipe (5).
2) Dew condensation on the surface can be prevented. Further, the refrigerant pipe (52) can be protected from external impact and pressure by the inner peripheral portion (11) having excellent flexibility. Further, the inner peripheral portion (1) of the insulator (10) can be changed only by changing the foaming ratio of the insulator (10) made of a single material.
Since the specific gravities of 1) and the outer peripheral part (12) can be changed, the insulator (10) can be produced at a lower cost than in the case where two tubular members having different specific gravities are stacked to form an insulator.

According to the second aspect of the invention, since the outer peripheral portion (12) is made of an unfoamed material, the outer peripheral portion (12) does not contain bubbles. Therefore, the vibration sound of the pipe can be reflected by the outer peripheral portion (12), and in addition to the above-described soundproof effect, a sound insulation effect that prevents the sound from being transmitted to the outside can be obtained. Here, it is generally known that the more the air layer is interposed between the sound source and the sound insulation wall, the greater the sound insulation effect of the sound insulation wall becomes. And according to the present invention, the outer peripheral portion (12) which is a sound insulation wall,
Since the inner peripheral portion (11) containing a large amount of air bubbles is interposed between the refrigerant pipe (52) which is a sound source, the sound insulating effect by the outer peripheral portion (12) can be effectively exhibited.

In the invention according to claim 3, the insulator (1) is made of an ethylene-propylene copolymer which is cheaper than the above-mentioned mixed foam of hydrophobic urethane and bituminous material.
Since 0) is formed, the cost can be reduced. In the invention according to claim 4, the compressor (2)
In the air conditioning refrigeration cycle apparatus (1) including a condenser (3), an expansion valve (5), and an evaporator (6), the low pressure side refrigerant pipe (52) is provided with the insulator (10) outside. Since it is inserted, the vibration noise of the refrigerant pipe of the air conditioning refrigeration cycle apparatus (1) can be reduced.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, the outlet pipe 5 of the expansion valve 5 in the refrigeration cycle apparatus 1 for vehicle air conditioning shown in FIG.
2, the insulator 10 of the present invention is extrapolated. The refrigeration cycle apparatus 1 includes a compressor 2, a condenser 3, a liquid receiver 4,
The expansion valve 5 and the evaporator 6 are sequentially connected by a refrigerant pipe. It should be noted that FIG. 2 illustrates only the inlet pipe 51, the outlet pipe 52 of the expansion valve 5, and the low-pressure pipes 61 and 62 connecting the expansion valve 5 and the evaporator 6, and omits the other pipes. It is indicated by an arrow. The dash panel 7 divides the vehicle compartment R from the engine room E, and an expansion valve 5 and an evaporator 6 are provided in an air conditioning case 8 for vehicle air conditioning arranged in the vehicle compartment R. .

The expansion valve 5 and the evaporator 6 are provided at positions facing the engine 9 via the dash panel 7 and are located in the vicinity of the central portion C in the passenger compartment R. The compressor 2, the condenser 3, and the liquid receiver 4 are arranged around the engine 9 in the engine room E. Then, one end 51 of the inlet and outlet pipes 51, 52 of the expansion valve 5
Reference numerals 1 and 521 are connected to a refrigerant inlet and outlet (not shown) of the expansion valve 5, respectively, and the other ends 512 and 522 are connected to a joint portion 70 fixed to the dash panel 7. The inlet and outlet pipes 51 and 52 pass through a through hole 81 formed in the air conditioning case 8 on the way.

A communication passage (not shown) that connects the other end 512 of the inlet pipe 51 and the refrigerant outlet side of the liquid receiver 4 to the joint portion 70, the other end 522 of the outlet pipe 52 and the refrigerant inlet of the compressor 2. A communication passage (not shown) that communicates with the side is formed. Since there is no space between the engine 9 and the dash panel 7, the inlet and outlet pipes 5 of the expansion valve 5
Regarding 1, 52, from the portion penetrating the through hole 81 of the air conditioning case 8 to the other end 512 of the inlet and outlet pipes 51, 52,
Up to 522 is exposed in the vehicle interior R. And FIG.
As also shown, the insulator 10 is externally fitted so as to surely cover the outlet pipe 52 exposed in the vehicle interior R.

Specifically, the length of the insulator 10 is
In addition to the portion of the outlet pipe 52 exposed in the vehicle interior R, the length of the outlet pipe 52 that can be reliably extrapolated up to the portion arranged in the air conditioning case 8 rather than the through hole 81 of the air conditioning case 8, In this embodiment, it is 430 mm. 3 (a) and 3 (b), the inner peripheral portion 11 of the insulator 10 has an expansion ratio of 5 EPD.
The outer peripheral portion 12 is made of EPDM in an unfoamed state, and the inner peripheral portion 11 and the outer peripheral portion 12 are integrally formed. EPDM is a foamable material, and is expressed by expansion ratio = volume of EPDM after foaming / volume of EPDM in an unfoamed state. The unfoamed EPDM is EPDM that does not contain bubbles. It should be noted that in the unfoamed EPDM, there may be residual bubbles that are inevitably formed during manufacture, but this is not included in the bubbles in the present embodiment.

Then, the inner peripheral portion 11 and the outer peripheral portion 12 are each made to have the expansion ratio as described above, whereby the inner peripheral portion 11 is formed.
Has a specific gravity of about 0.25, and the outer peripheral portion 12 has a specific gravity of about 1.21.
Becomes Further, the inner peripheral portion 11 containing bubbles is relatively excellent in flexibility, and the outer peripheral portion 12 not containing bubbles is relatively inferior in flexibility. Here, the outer diameter is, for example, 1 so that the insulator 10 can be smoothly inserted into the outlet pipe 52 of the expansion valve 5.
The inner diameter of the inner peripheral portion 11 is, for example, 16.0 mm with respect to the outlet pipe 52 of 5.9 mm. Further, if the thickness of the insulator 10 is too large, the insulator 10 cannot be extrapolated to the outlet pipe 52 in terms of space, so the thickness of the insulator 10 is set to 5 mm, for example.

If the inner peripheral portion 11 having a small specific gravity is large and the outer peripheral portion 12 having a large specific gravity is too small,
If the inner peripheral portion 11 having excellent flexibility is made small and the outer peripheral portion 12 having inferior flexibility is made too large, the sound insulating effect described later may not be effectively obtained, and the insulator 10 is smoothly connected to the outlet pipe 52. May not be extrapolated to.
Considering these, the thickness of the inner peripheral portion 11 is set to, for example, 4.0 m.
The wall thickness of the outer peripheral portion 12 is, for example, 1 mm. Thereby, the tubular insulator 10 that can be externally inserted into the outlet pipe 52 can be configured.

Here, in the refrigerant pipe of the vehicle refrigeration cycle 1 shown in FIG. 2, the refrigerant hits the inner wall of the refrigerant pipe, so that the refrigerant pipe vibrates or expands due to the vibration of the expansion valve during the operation of the expansion valve. The refrigerant pipe connected to the valve vibrates. The vibration of the refrigerant pipe causes vibration noise of the refrigerant pipe. By the way, since this vibration sound is perceived as a noise (noise) that is harsh to the occupant only when it is transmitted to the vehicle interior R, the vibration sound of the low-pressure pipes 61 and 62 incorporated in the air conditioning case 8 is Since the sound is shielded by the air-conditioning case 8, the noise is not a serious problem.

Further, it has been confirmed by the experiments of the inventors that the vibration noise of the outlet pipe 52 on the low pressure side is very large, and the vibration noise of the inlet pipe 53 on the high pressure side is not a serious problem. Therefore, in the present embodiment, the insulator 10 is externally attached only to the outlet pipe 52 exposed in the vehicle interior R. Below, the mounting method of the insulator 10 is shown.

First, in FIG. 2, the joint portion 70 is removed from the dash panel 7, the inlet portion of the expansion valve 5 and the other ends 512 and 522 of the outlet pipes 51 and 52 are removed from the joint portion 70, and then the outlet pipe is formed. The insulator 10 is extrapolated from the other end 522 side of 52. Then, after the insulator 10 is extrapolated as shown in FIG. 1, the other ends 512 and 522 of the inlet and outlet pipes 51 and 52 are connected to the joint portion 7 shown in FIG.
0 and the joint 70 is fixed to the dash panel 7.

Further, according to the present embodiment, since the outer peripheral portion 12 having a large specific gravity in the insulator 10 can provide a high soundproofing effect, it can be made thinner than the case where the soundproofing effect is obtained only by a member having a high expansion ratio. Insulator 10 can be used. In addition, the insulator 10 can be attached to the outlet pipe 52 by a simple operation of externally inserting the tubular insulator 10 into the outlet pipe 52, and compared to a case where two long plate members are bonded with an adhesive. The workability of mounting the insulator 10 can be improved. Moreover, since the inner peripheral portion 11 containing a large amount of bubbles is relatively excellent in flexibility, the workability of attaching the insulator 10 can be further improved.

Further, since the inner peripheral portion 11 containing a large amount of air bubbles has poor thermal conductivity, the inner peripheral portion 11 functions as a heat buffering material between the outlet pipe 52 and the outside, and it is possible to prevent dew condensation on the surface of the outlet pipe 52. . Further, the outlet pipe 52 can be protected from external impact and pressure by the inner peripheral portion 11 having excellent flexibility. In addition, the vibration sound of the outlet pipe 52 can be reflected at the outer peripheral portion 12 that does not include bubbles, and in addition to the above-described soundproof effect, a sound insulation effect that prevents sound from being transmitted to the outside can be obtained. Here, it is generally known that the more the soundproof layer (for example, the air layer) is interposed between the sound source and the sound insulation wall, the greater the sound insulation effect by the sound insulation wall becomes. Further, according to the present embodiment, since the inner peripheral portion 11 containing many bubbles is interposed between the outer peripheral portion 12 which is the sound insulating wall and the outlet pipe 52 which is the sound source, the sound insulating effect by the outer peripheral portion 12 is effective. You can get it.

An experiment for evaluating the soundproofing effect when the insulator 10 of the present invention is adopted in an actual vehicle having an outside air of 35 ° C. will be described below. First, in an actual vehicle in which the insulator 10 is externally inserted into the outlet pipe 52, a sound collecting microphone is attached to the central portion C in the vehicle compartment R so that the noise level in the vehicle compartment R of the actual vehicle can be measured. The noise level when the ignition switch is turned on and the air conditioner switch is off (shown by the dotted line in FIG. 4) and the noise level when the ignition switch is turned on and the air conditioner switch is turned on (shown by the solid line in FIG. 4) Were measured by the sound collecting microphone, and the results are shown in FIG. The number of rotations of the compressor 2 was 900 rpm.

Further, the insulator 10 is connected to the outlet pipe 52.
For actual vehicles that do not have the
The noise level (dB) was measured in the same manner as the above measurement, and the result is shown in FIG. In the comparative product shown in FIG.
The difference between the overall values when the air conditioner switch was on and when it was off was 4.2 dB. And according to the graph of FIG. 5, when the air conditioner switch is turned on, about 2K
It can be seen that the noise in the high frequency region above Hz becomes extremely large. Therefore, the vibration noise of the outlet pipe 52 is about 2 KHz.
It can be confirmed that the noise occurs in the above high frequency range. The overall value is an average noise level of 0 to 12 KHz.

Then, in the above-mentioned prior art, EPDM
Since the insulator made of the foam has a small specific gravity and a small thickness, the soundproofing effect cannot be expected, and the noise level tends to be similar to the noise level of the comparative product shown in FIG.
On the other hand, according to the product of the present invention shown in FIG. 4, the difference in overall value is 2.9 dB, and it is possible to achieve noise reduction of 1.3 dB in overall value as compared with the comparative product. Then, focusing on the high frequency region of about 2 KHz or more, by mounting the insulator 10, the vehicle interior R
The vibration noise of the outlet pipe 52 transmitted inside can be effectively prevented,
Noise that reaches the ears of passengers can be prevented.

Although the insulator 10 is formed of EPDM in the above embodiment, other materials may be used. Here, as the material of the insulator 10, the foaming ratio can be changed, and the insulator 10 is flexible enough to be externally inserted into the outlet pipe 52,
In addition, it may be formed in a tubular shape and has a rigidity that allows it to be inserted into the outlet pipe 52.

Further, in the above embodiment, the foaming ratio of the inner peripheral portion 11 of the insulator 10 is set to 5 and the outer peripheral portion 12 is not foamed. The expansion ratios of the peripheral portion 11 and the outer peripheral portion 12 may be changed. Further, in the above-described embodiment, as shown in FIG. 2, the evaporator 6 and the expansion valve 5 are arranged in the vicinity of the central portion C in the vehicle compartment R, but the invention is not limited to this, and the evaporator is not limited to this. The expansion valve 6 and the expansion valve 5 may be arranged laterally in the vehicle compartment R.

Further, in the above embodiment, the inner diameter of the insulator 10 is substantially the same as the outer diameter of the outlet pipe 52, but the present invention is not limited to this, and the insulator 10 is not limited to this.
The inner diameter may be larger than the outer diameter of the outlet pipe 52. Further, in the above embodiment, the present invention is applied to the low-pressure side outlet pipe 52 of the refrigeration cycle 1 for vehicle air conditioning, but the present invention may be applied to various other refrigerant pipes.

Further, in the above embodiment, the present invention is applied only to the outlet pipe 52. However, even if the present invention is applied to another refrigerant pipe portion, for example, the inlet pipe 51, the noise reduction effect is obtained. Obtainable.

[Brief description of drawings]

FIG. 1 is a front view showing a mounted state of an insulator according to an embodiment of the present invention.

FIG. 2 is a partial schematic configuration diagram of an automobile air conditioner using the insulator of the present invention.

3A is a side view of the insulator, and FIG. 3B is a sectional view taken along line AA of FIG.

FIG. 4 is a graph showing a noise level of an actual vehicle equipped with the insulator of the present invention.

FIG. 5 is a graph showing a noise level of an actual vehicle in which the insulator of the present invention is not mounted.

[Explanation of symbols]

10 ... Insulator, 11 ... Inner peripheral part, 12 ... Outer peripheral part,
52 ... Outlet pipe (low-pressure refrigerant pipe).

Claims (4)

[Claims] 1. An insulator, which is formed of a single material capable of being foamed by being inserted into a refrigerant pipe (52) through which a refrigerant flows, wherein the expansion ratio = the volume of the material after foaming / the material in an unfoamed state. The insulator is formed in a tubular shape so that the foaming ratio of the outer peripheral portion (12) is lower than that of the inner peripheral portion (11) when expressed by the volume. 2. The insulator according to claim 1, wherein the outer peripheral portion (12) is made of an unfoamed material. 3. The insulator according to claim 1, wherein the foamable single material is an ethylene-propylene copolymer. 4. A compressor (2) for compressing and discharging a refrigerant.
A condenser (3) for cooling and condensing the gas refrigerant discharged from the compressor (2); an expansion valve (5) for decompressing and expanding the refrigerant flowing from the condenser (3); An evaporator (6) for evaporating the expanded refrigerant decompressed by the valve (5), the compressor (2), the condenser (3), the expansion valve (5), and the evaporator (6). The refrigerant | coolant piping (51, 52, 61, 62) which connects in order is provided, The insulator (10) according to any one of claims 1 to 3 is extrapolated to the low-pressure side low-pressure refrigerant piping (52). A refrigeration cycle device for air conditioning, which is characterized in that