WO2024158023A1

WO2024158023A1 - Accumulator

Info

Publication number: WO2024158023A1
Application number: PCT/JP2024/002127
Authority: WO
Inventors: 侯史細川; 武治小澤; 真聖杉野; 晃平福山
Original assignee: 株式会社不二工機
Priority date: 2023-01-26
Filing date: 2024-01-25
Publication date: 2024-08-02

Abstract

Provided is an accumulator capable of holding a gas-liquid separating body and increasing an amount of refrigerant that passes through, while preventing an increase in the number of components. The accumulator comprises a body portion having an opening in at least one end, a header which has a refrigerant inflow hole and a refrigerant outflow hole and which blocks the opening in said one end of the body portion, a gas-liquid separating member disposed within the body portion and facing the refrigerant inflow hole and the refrigerant outflow hole, and an outflow pipe connected to the refrigerant outflow hole, wherein: the outflow pipe includes a small-diameter cylinder portion inserted into and fixed to the refrigerant outflow hole, and a large-diameter cylinder portion which has a larger diameter than the small-diameter cylinder portion and which is disposed within the body portion; the gas-liquid separating member is sandwiched between a stepped surface, which is an end surface of the large-diameter cylinder portion on the small-diameter cylinder portion side thereof, and the header; and the outflow pipe has a cylindrical inner circumferential surface formed within the small-diameter cylinder portion, and a tapered inner circumferential surface which is joined to the cylindrical inner circumferential surface and which contracts diametrically toward the refrigerant outflow hole.

Description

accumulator

The present invention relates to an accumulator.

Receiver tanks and accumulators are used to separate the refrigerant circulating through the refrigeration cycle into gas and liquid and store it.

Patent Document 1 discloses an example of an accumulator. In a refrigeration cycle, high-pressure gas-phase refrigerant discharged from a compressor flows into a condenser where it is cooled and condensed by heat exchange with outside air. The liquid refrigerant condensed in the condenser is then depressurized in a pressure reducing device to become mist-like gas-liquid phase. The low-pressure refrigerant after depressurization absorbs heat from the air blown by the air conditioner blower in the evaporator and evaporates. As is well known, the air cooled by the evaporator is temperature-adjusted in a heater core (not shown) before being blown into the passenger compartment, for example. The refrigerant that has passed through the evaporator is separated into gas and liquid in the accumulator before being drawn into the compressor.

For this purpose, the header of the accumulator is formed with a refrigerant inlet and a refrigerant outlet that communicate with the inside of the accumulator. The refrigerant inlet is connected to the evaporator via a pipe, and the refrigerant outlet is connected to the compressor via a pipe.
Also known is an accumulator having a gas-liquid separating member (cup) that separates the refrigerant flowing in from a refrigerant inlet into a liquid-phase refrigerant and a gas-phase refrigerant, as disclosed in Patent Document 1.

JP 2014-52139 A

In order to improve the performance of the refrigeration cycle, there is a demand to increase the amount of refrigerant passing through the accumulator. One idea for increasing the amount of refrigerant passing through the accumulator is to use an outlet pipe with a large inner diameter that is placed inside the accumulator and connected to the refrigerant outlet of the header.

However, the diameter of the refrigerant outlet formed in the header is determined according to the piping that constitutes the flow path downstream of the accumulator, and this piping is often designed by the manufacturer that assembles the refrigeration cycle. In this way, the specifications of the refrigerant outlet of the accumulator are determined by the size of the designed piping, which creates the problem that it is difficult to use an outlet pipe with a large inner diameter regardless of the size of the piping connected to it.

In response to this, it is possible to use an outflow pipe with a partially large diameter, but this has the following problems. For example, in the case of an accumulator having a gas-liquid separating member (cup) that separates the liquid phase refrigerant and gas phase refrigerant in the refrigerant introduced from the refrigerant inlet, as in Patent Document 1, in order to hold this gas-liquid separator in the accumulator, a flange is formed by bulging the end of the outflow pipe near the refrigerant outlet side, and the cup is held by gripping it between the flange and the header. Because of the bulging process, a pipe member is used as the outflow pipe, which makes it difficult to use an outflow pipe with a partially large diameter as the outflow pipe.

The present invention was made in consideration of these problems, and aims to provide an accumulator that can hold a gas-liquid separator and increase the amount of refrigerant passing through while preventing an increase in the number of parts.

In order to achieve the above object, the accumulator according to the present invention comprises:
a body portion having an opening at at least one end;
a header having a refrigerant inlet and a refrigerant outlet, the header closing an opening at one end of the body;
a gas-liquid separating member disposed within the body portion and facing the refrigerant inlet and the refrigerant outlet;
an outflow pipe connected to the refrigerant outflow hole,
the outflow pipe includes a small diameter cylindrical portion that is inserted into and fixed to the refrigerant outflow hole, and a large diameter cylindrical portion that is larger in diameter than the small diameter cylindrical portion and that is disposed within the body portion, the gas-liquid separating member is sandwiched between the header and a step surface that is an end surface of the large diameter cylindrical portion on the side of the small diameter cylindrical portion,
The outflow pipe has a cylindrical inner circumferential surface formed within the small diameter cylindrical portion, and a tapered inner circumferential surface that is connected to the cylindrical inner circumferential surface and reduces in diameter toward the refrigerant outflow hole.

The present invention provides an accumulator that can hold a gas-liquid separator and increase the amount of refrigerant passing through it while preventing an increase in the number of parts.

FIG. 1 is a vertical cross-sectional view of an accumulator according to a first embodiment. FIG. 2 is a cross-sectional view showing the header, the cup, and the inner pipe in an exploded state. FIG. 3 is a vertical cross-sectional view of an accumulator according to the second embodiment. FIG. 4 is a vertical cross-sectional view of an inner pipe according to the second embodiment. FIG. 5 is an enlarged cross-sectional view showing the lower end of the inner pipe of this embodiment. FIG. 6 is an enlarged cross-sectional view showing a lower end of an inner pipe according to the first modified example. FIG. 7 is an enlarged cross-sectional view showing a lower end of an inner pipe according to the second modification. FIG. 8 is an enlarged cross-sectional view showing a lower end of an inner pipe according to a third modified example. FIG. 9 is a vertical cross-sectional view of an inner pipe according to the third embodiment. FIG. 10 is a vertical cross-sectional view of an inner pipe according to the fourth embodiment.

The accumulator 1 according to an embodiment of the present invention will now be described with reference to the attached drawings.

(First embodiment)
1 is a vertical cross-sectional view of an accumulator 1 according to a first embodiment, with only the left half of the strainer shown in cross section. The accumulator 1 has a tank body 2, a double pipe 5 arranged in the tank body 2, a bag 11 containing a desiccant (moisture absorbent) DA, a cup (also called a gas-liquid separating member) 16, and a strainer 20.

The tank body 2 is composed of a cylindrical body 3 with a bottom and an open top, and a header 4 that is joined to the body 3 by circumferential welding via a weld 10 and closes the opening of the body 3. The body 3 is a body portion having an opening at least at one end. The body 3 and the header 4 are both formed from a metal such as an aluminum alloy. In this specification, the header 4 side is referred to as the upper side, and the bottom side of the body 3 is referred to as the lower side. As another example of the body 3, the body 3 may be cylindrical with openings at both ends. In this configuration, one opening is closed by the header 4, and the other opening is closed by a member separate from the body 3. In this configuration, the member that closes the other opening of the body 3 is formed from a metal such as an aluminum alloy.

The header 4 is formed in a roughly disk shape, and has a refrigerant inlet hole 8 and a refrigerant outlet hole 9 formed vertically through it. An inner pipe (also called an outlet pipe) 6 that extends close to the inside bottom of the body 3 is connected to the refrigerant outlet hole 9. An outer pipe 7 is fitted around the outside of the inner pipe 6, forming a double pipe 5.

Below the header 4, a cup 16 is provided as a gas-liquid separating member that separates the mixed refrigerant (a mixture of gas and liquid phases) from the refrigerant inlet 8 into high density liquid phase refrigerant and compressor oil (hereinafter referred to as "oil") and low density gas phase refrigerant. The cup 16 has a cylindrical shape with a top, and is positioned opposite the refrigerant inlet 8 and the refrigerant outlet 9.

The inner pipe 6 is made of a metal such as an aluminum alloy, has an open lower end, and has an upper end connected to a refrigerant outlet hole 9 of the header 4, as described below. The outer periphery of the inner pipe 6 is fitted inside a number of pipe ribs 7a protruding from the inner periphery of the outer pipe 7, so that the inner pipe 6 is stably held within the outer pipe 7 with a gap therebetween.

The outer pipe 7 is made of synthetic resin and is attached inside the body 3 with its upper end open. A cylindrical strainer 20 is provided at the bottom of the outer pipe 7. The strainer 20 is composed of a cylindrical case 21 with a bottom made of synthetic resin, and a cylindrical mesh filter 22 that is integrated with the case 21 by insert molding or the like.

A bag 11 containing a desiccant DA is placed between the outer pipe 7 and the inner circumference of the body 3.

FIG. 2 is a cross-sectional view showing the header 4, cup 16, and inner pipe 6 in an exploded state. The header 4 is made up of a large cylindrical portion 4a and a step portion 4c that are stacked and connected together, and the step portion 4c is formed on the outer periphery of the lower end of the large cylindrical portion 4a with which the outer periphery of the upper end of the body 3 engages. The upper surface of the large cylindrical portion 4a is formed, for example, on a plane that is perpendicular to the vertical direction.

A cylindrical boss 4d is formed on the underside of the header 4, protruding downward from the large cylindrical portion 4a. A refrigerant outlet hole 9 is formed through the boss 4d, penetrating the header 4 from top to bottom, and a refrigerant inlet hole 8 is formed adjacent to the boss 4d, penetrating the header 4 from top to bottom. The underside of the boss 4d is formed, for example, on a plane that is in surface contact with the upper surface of the top wall 16b of the cup 16, which will be described later. The underside of the boss 4d is formed, for example, on a plane that is perpendicular to the axis of the inner pipe 6.

The refrigerant outlet hole 9 has a large diameter hole 9a formed at the top and a female thread 9b formed at the bottom. The inner diameter of the large diameter hole 9a is larger than the root diameter of the female thread 9b.

The cup 16 is formed by connecting a side wall 16a and a top wall 16b. A through hole 16c is formed in the top wall 16b. For example, one or more ribs 16b1 are formed on the upper surface of the top wall 16b. The ribs 16b1 are formed in a shape that protrudes upward. The ribs 16b1 constitute a part of the upper surface of the top wall. The upper surface of the top wall 16b of the cup 16, in a range where the lower surface of the boss 4d of the header 4 abuts, is formed in a plane that is in surface contact with the lower surface of the boss 4d. The upper surface of the top wall 16b of the cup 16, in a range where the lower surface of the boss 4d of the header 4 abuts, is formed in a plane that is perpendicular to the axis of the inner pipe 6. Alternatively, a part of the rib 16b1 may be formed in the upper surface of the top wall 16b of the cup 16, in a range where the lower surface of the boss 4d of the header 4 abuts. In this configuration, a recess is formed in the lower surface of the boss 4d of the header 4 to arrange a part of the rib 16b1. This recess has, for example, a shape into which the rib 16b1 fits.
The lower surface of the top wall 16b is formed, for example, as a plane that comes into surface contact with a step surface 6d of the inner pipe, which will be described later, and is formed, for example, as a plane that is perpendicular to the axis of the inner pipe.

Top wall 16b faces both refrigerant inlet hole 8 and refrigerant outlet hole 9. Furthermore, top wall 16b is a portion against which the refrigerant flowing in from refrigerant inlet hole 8 collides. Furthermore, top wall 16b faces the entire refrigerant inlet hole 8. The facing direction is the axial direction of refrigerant inlet hole 8.
Furthermore, the gap between the header 4 and the top wall 16b and the gap between the side wall 16a and the inner circumferential surface of the body 3 are approximately the same. Here, "approximately the same" may include an error in addition to being completely the same. That is, when the refrigerant flowing in from the refrigerant inlet hole 8 collides with the top wall 16b and flows downstream, it flows through the gap between the top wall 16b and the header 4 and the gap between the inner circumferential surface of the body 3 and the side wall 16a. If these gaps are "the same", the smooth flow of the refrigerant is maintained. In addition, if there is a small error in these gaps, the state in which the refrigerant flows smoothly can be maintained. The error is an error that can maintain the flow of the refrigerant smoothly in this way.

The inner pipe 6 is formed, for example, by cutting an aluminum material, and is made up of a small diameter cylindrical portion (also called a small diameter cylindrical portion) 6a that is inserted and fixed into the refrigerant outflow hole 9, and a large diameter cylindrical portion (also called a large diameter cylindrical portion) 6b that is larger in diameter than the small diameter cylindrical portion 6a and is placed inside the body 3. A male thread 6c is formed on the outer periphery of the small diameter cylindrical portion 6a, which has a diameter smaller than the through hole 16c.

The outer diameter of the small diameter cylindrical portion 6a is smaller than the outer diameter of the large diameter cylindrical portion 6b, so that an annular step surface 6d facing the refrigerant outlet hole 9 is formed between the small diameter cylindrical portion 6a and the large diameter cylindrical portion 6b. The step surface 6d, which is the end surface of the large diameter cylindrical portion 6b on the small diameter cylindrical portion 6a side, is perpendicular to the axis L of the inner pipe 6.

Furthermore, the inner pipe 6 has a cylindrical inner peripheral surface 6e extending inside the small diameter cylindrical portion 6a, and a tapered inner peripheral surface 6f on the lower end side that connects to the cylindrical inner peripheral surface 6e near the step surface 6d. The tapered inner peripheral surface 6f, which reduces in diameter toward the cylindrical inner peripheral surface 6e side (upper end side), may extend to the lower end of the inner pipe 6, or may extend to the vicinity of the lower end of the inner pipe 6. When the tapered inner peripheral surface 6f extends to the vicinity of the lower end of the inner pipe, the tapered inner peripheral surface 6f and the lower end can be connected by another cylindrical inner peripheral surface. The taper angle θ of the tapered inner peripheral surface 6f is uniform and is preferably 10 degrees or more.

A pressure equalizing hole 6g is formed near the step surface 6d of the inner pipe 6. The pressure equalizing hole 6g penetrates the inner pipe 6. The pressure equalizing hole 6g is a hole that prevents the liquid phase refrigerant that has accumulated in the inner pipe 6 from being sucked up by the compressor when the compressor is started again after the refrigeration cycle has stopped (after the compressor has stopped operating). In other words, the pressure equalizing hole 6g allows not only the liquid phase refrigerant in the inner pipe 6 but also the gas phase refrigerant outside the inner pipe 6 to be sucked up by the compressor, thereby preventing the liquid phase refrigerant from being sucked up.

When assembling the header 4, cup 16, and inner pipe 6, first, the lower end of the boss 4d of the header 4 is brought into contact with the upper surface of the cup 16 and the periphery of the through hole 16c. Note that, on the upper surface of the top wall 16b, the rib 16b1 is formed, for example, at a position that avoids the area where the boss 4d comes into contact. Therefore, in this embodiment, the lower end of the boss 4d comes into surface contact with the flat portion of the upper surface of the top wall 16b.
Next, the inner pipe 6 is brought close to the cup 16 from below. Further, the small diameter cylindrical portion 6a of the inner pipe 6 is inserted into the through hole 16c, and the male thread 6c is screwed into the female thread 9b of the header 4.

Then, when the male thread 6c is screwed into the female thread 9b, the inner pipe 6 approaches the header 4, and the step surface 6d comes into contact with the bottom surface of the cup 16 around the through hole 16c. The bottom surface of the top wall 16b of the cup 16 comes into surface contact with the step surface 6d. At this time, the cup 16 is clamped and fixed between the bottom end of the boss 4d and the step surface 6d. Compared to bulge processing, the flatness of the step surface 6d is ensured to be high, so even if the area of the step surface 6d is small, the cup 16 can be held in an appropriate position by coming into surface contact with the bottom surface of the cup 16. The outer pipe 7 and strainer 20 are assembled into the inner pipe 6, and the assembly formed in this way is installed in the body 3 in which the bag 11 is arranged, and welded to the header 4 to complete the accumulator 1.

According to this embodiment, a small diameter cylindrical portion 6a is formed to match the refrigerant outflow hole 9 of the header 4, and a large diameter cylindrical portion 6b is formed to obtain a flow rate according to the performance required of the accumulator 1, and further, a stepped surface 6d is formed to clamp the cup 16 against the header 4, thereby fixing the cup 16. In this way, it is possible to provide an accumulator 1 that can hold the gas-liquid separator and increase the amount of refrigerant passing through, while preventing an increase in the number of parts.

In this embodiment, the inner pipe 6 is fastened to the header 4 by screwing the female thread 9b into the male thread 6c, eliminating the need for the conventional crimping process of the inner pipe 6 (no crimping portion is provided inside the refrigerant outflow hole 9). This eliminates the need to insert a crimping tool into the refrigerant outflow hole 9, and also eliminates the need to expand the diameter of the end of the inner pipe 6 by plastic deformation to engage with the step inside the refrigerant outflow hole 9. As a result, the inner diameter of the small diameter cylindrical portion 6a can be expanded regardless of the inner diameter of the refrigerant outflow hole 9, reducing pressure loss inside the inner pipe 6 and ensuring a smooth flow of the refrigerant.

Furthermore, according to this embodiment, the cup 16 is attached to the header 4 by being sandwiched between the step surface 6d formed on the inner pipe 6 and the boss 4d of the header 4, eliminating the need for bulge processing of the inner pipe 6. This reduces the resistance of the refrigerant flowing through the inner pipe 6 and suppresses the occurrence of turbulence, ensuring a smooth flow of the refrigerant.

In addition, according to this embodiment, the inner pipe 6 is formed with a tapered inner circumferential surface 6f, so that the inner diameter gradually decreases toward the cylindrical inner circumferential surface 6e, which is the refrigerant outlet side, thereby reducing pressure loss and ensuring an even smoother flow of the refrigerant.

The operation of the accumulator 1 configured as above will be explained with reference to Figure 1. In the following explanation, an example will be given in which the accumulator 1 is placed between the evaporator and compressor of the refrigeration cycle, and the moisture contained in the refrigerant from the evaporator is removed to generate gas refrigerant, which is then returned to the compressor.

When the refrigerant is discharged from the evaporator, it is transported to the accumulator 1 through a connecting pipe (not shown). After reaching the accumulator 1, the refrigerant flows into the body 3 through the refrigerant inlet 8, and then collides with the upper surface of the cup 16, where it is separated into high-density liquid-phase refrigerant and oil, and low-density gas-phase refrigerant (gas refrigerant).

After gas-liquid separation, the liquid refrigerant and oil are stored in the body 3 due to their own weight. During this process, the liquid refrigerant and oil continue to separate, and the oil accumulates below the liquid refrigerant. At this time, the liquid level of the liquid refrigerant reaches a height position where part of the desiccant-containing bag 11 is immersed. Therefore, both the moisture contained in the liquid refrigerant and the humidity contained in the gas refrigerant are absorbed by the desiccant DA.

Meanwhile, the gas-phase refrigerant that has been separated into gas and liquid flows in from the upper opening of the outer pipe 7 and descends inside the outer pipe 7. It then turns around at the bottom of the outer pipe 7, passes over the lower end of the inner pipe 6, and flows inside, then rises inside the inner pipe 6 and is led to the refrigerant outlet hole 9.

The oil that accumulates at the bottom of the body 3 together with the liquid refrigerant moves to the bottom side of the body 3 due to differences in specific gravity and properties compared to the liquid refrigerant, and is sucked into the gas refrigerant being sucked into the compressor suction side, passing through the mesh filter 22 of the strainer 20, the oil return hole 7e, and the internal space of the inner pipe 6, in that order, before being returned to the compressor suction side together with the gas refrigerant and circulated. As it passes through the mesh filter 22, foreign matter such as sludge is captured and removed from the circulating refrigerant (including oil).

Second Embodiment
Fig. 3 is a vertical cross-sectional view of an accumulator 1A according to a second embodiment, but only the left half of the strainer is shown in cross section as in Fig. 1. Fig. 4 is a vertical cross-sectional view of an inner pipe 6A according to the second embodiment. Fig. 5 is an enlarged cross-sectional view of the lower end of the inner pipe 6A.

In this embodiment, only the inner pipe 6A is different from the first embodiment, and the other configuration is the same as the first embodiment, so the same symbols are used for the common configuration and duplicate explanations are omitted.

The inner pipe 6A in this embodiment is formed, for example, by forging an aluminum material, and is composed of a small diameter cylindrical portion 6Aa and a large diameter cylindrical portion 6Ab connected together. A male thread 6Ac is formed on the outer periphery of the small diameter cylindrical portion 6Aa.

The outer diameter of the small diameter cylindrical portion 6Aa is smaller than the outer diameter of the large diameter cylindrical portion 6Ab, so that a step surface 6Ad is formed between the small diameter cylindrical portion 6Aa and the large diameter cylindrical portion 6Ab, and a pressure equalizing hole 6Ag1 is formed in the vicinity of the step surface 6Ad. The step surface 6Ad is perpendicular to the axis L of the inner pipe 6A.

Furthermore, the inner pipe 6A has a first cylindrical inner circumferential surface 6Ae on the upper end side, a tapered inner circumferential surface 6Af on the lower end side that connects to the first cylindrical inner circumferential surface 6Ae near the step surface 6Ad, and a second cylindrical inner circumferential surface 6Ag that connects to the tapered inner circumferential surface 6Af. The taper angle θ of the tapered inner circumferential surface 6Af is uniform, and is preferably 60 degrees or more when formed by forging.

In this embodiment, the second cylindrical inner surface 6Ag maintains a cylindrical shape up to the lower end 6Ah of the inner pipe 6A, and the outer surface of the large diameter cylindrical portion 6Ab maintains a cylindrical shape. Furthermore, the lower end 6Ah is an end surface perpendicular to the axis L (see FIG. 5).

In this embodiment, the cup 16 is placed between the header 4 and the inner pipe 6A, and then the small diameter cylindrical portion 6Aa of the inner pipe 6A is inserted into the through hole 16c, and the male thread 6Ac is screwed into the female thread 9b of the header 4 to assemble the cup 16. As a result, the cup 16 is clamped and fixed between the lower end of the boss 4d and the step surface 6Ad.

(Variation 1)
Fig. 6 is an enlarged cross-sectional view of the lower end of the inner pipe 6B according to the first modified example. In this modified example, the outer circumferential surface of the large-diameter cylindrical portion 6Bb has a cylindrical shape up to the lower end 6Bh of the inner pipe 6B, but the second cylindrical inner circumferential surface 6Bg gradually expands in diameter from the vicinity of the lower end 6Bh toward the lower end 6Bh, and intersects with the outer circumferential surface of the large-diameter cylindrical portion 6Bb at the lower end 6Bh. In the cross section shown in Fig. 6, the second cylindrical inner circumferential surface 6Bg in the vicinity of the lower end 6Bh preferably has an arc shape.

Referring to FIG. 1, according to this modified example, when the gas-liquid separated gas-phase refrigerant turns around at the bottom of the outer pipe 7 and flows inward beyond the lower end 6Bh of the inner pipe 6B, it flows along the gradually enlarging second cylindrical inner surface 6Bg, ensuring a smooth flow of the refrigerant.

(Variation 2)
Fig. 7 is an enlarged cross-sectional view of the lower end of the inner pipe 6C according to the second modification. In this modification, the second cylindrical inner circumferential surface 6Cg has a cylindrical shape up to the lower end 6Ch of the inner pipe 6C, but the outer circumferential surface of the large diameter cylindrical portion 6Cb gradually decreases in diameter from the vicinity of the lower end 6Ch toward the lower end 6Ch, and intersects with the second cylindrical inner circumferential surface 6Cg at the lower end 6Ch. In the cross section shown in Fig. 7, the outer circumferential surface of the large diameter cylindrical portion 6Cb in the vicinity of the lower end 6Ch preferably has an arc shape.

Referring to FIG. 1, in this modified example, when the gas-liquid separated gas-phase refrigerant is turned around at the bottom of the outer pipe 7 and flows toward the lower end 6Ch of the inner pipe 6C, it flows along the outer peripheral surface of the gradually reduced diameter large-diameter cylindrical portion 6Cb, ensuring a smooth flow of the refrigerant.

(Variation 3)
Fig. 8 is an enlarged cross-sectional view of the lower end of the inner pipe 6D according to the third modification. In this modification, the second cylindrical inner circumferential surface 6Dg gradually expands in diameter from the vicinity of the lower end 6Dh of the inner pipe 6D toward the lower end 6Dh, and the outer circumferential surface of the large diameter cylindrical portion 6Db gradually decreases in diameter from the vicinity of the lower end 6Dh toward the lower end 6Dh, and the second cylindrical inner circumferential surface 6Cg and the outer circumferential surface of the large diameter cylindrical portion 6Db intersect at the lower end 6Dh. In the cross section shown in Fig. 8, the lower end wall of the large diameter cylindrical portion 6Cb near the lower end 6Ch preferably has a semicircular arc shape.

Referring to FIG. 1, according to this modified example, when the gas-liquid separated gas-phase refrigerant turns around at the bottom of the outer pipe 7 and flows toward the lower end 6Dh of the inner pipe 6D, it flows along the outer peripheral surface of the gradually narrowing large diameter cylindrical section 6Db, and when it passes the lower end 6Dh of the inner pipe 6D and flows inward, it flows along the gradually expanding second cylindrical inner peripheral surface 6Dg, ensuring a smooth flow of the refrigerant.

Modifications 1 to 3 can also be applied to the inner pipe 6 in the first embodiment.

Third Embodiment
Fig. 9 is a vertical cross-sectional view of an accumulator 1F according to a third embodiment. In the accumulator 1F of this embodiment, the outflow pipe 6F is U-shaped and does not have an outer pipe. In Fig. 9, a strainer and a bag containing a desiccant are omitted. In this embodiment, the configurations of the header 4F and the outflow pipe 6F are different from those of the above-mentioned embodiment, and other configurations are the same as those of the above-mentioned embodiment. Therefore, the same reference numerals are used for the common configurations and a duplicated description will be omitted.

In this embodiment, the header 4F has a refrigerant outlet hole 9F that does not have a female thread, and has a large diameter hole 9Fa and a small diameter hole 9Fb. The rest of the configuration is the same as in the above-mentioned embodiment.

The outflow pipe 6F in this embodiment is formed by connecting a small diameter cylindrical section 6Fa and a large diameter U-shaped tubular section 6Fb that is bent into a U shape. The outer peripheral surface 6Fc of the small diameter cylindrical section 6Fa does not have a male thread, and has an outer diameter that is approximately the same as the inner diameter of the small diameter hole 9Fb.

The outer diameter of the small diameter cylindrical portion 6Fa is smaller than the outer diameter of the large diameter U-shaped cylindrical portion 6Fb, so that a step surface 6Fd is formed between the small diameter cylindrical portion 6Fa and the large diameter U-shaped cylindrical portion 6Fb. Furthermore, the outflow pipe 6F has a tapered inner circumferential surface 6Ff near the step surface 6Fd. The outflow pipe 6F also has a pressure equalizing hole 6Fg, as in the above-mentioned embodiment.

In this embodiment, after placing the cup 16 between the header 4F and the outflow pipe 6F, the small diameter cylindrical portion 6Fa of the outflow pipe 6F is inserted into the through hole 16c, and then the small diameter cylindrical portion 6Fa is fixed to the small diameter hole 9Fb of the header 4 by press fitting, brazing, welding, or the like. As a result, the cup 16 is clamped and fixed between the lower end of the boss 4Fd and the step surface 6Fd.

In this embodiment, the outflow pipe 6F can be attached by moving it linearly without rotating it relative to the header 4, so that the free end of the outflow pipe 6F can be positioned inside the cup 16 in the assembly position shown in Figure 9.

Fourth Embodiment
10 is a vertical cross-sectional view of an accumulator 1G according to the fourth embodiment. The accumulator 1G of this embodiment is different from the accumulator 1F of the third embodiment in the shape of the outflow pipe 6G. Specifically, the bending radius of the bent portion of the large-diameter U-shaped cylindrical portion 6Gb of the outflow pipe 6G is larger than the bending radius of the corresponding portion of the outflow pipe 6F of the third embodiment. The rest of the configuration is the same as in the above-mentioned embodiment. Also, the outflow pipe 6G has a pressure equalizing hole 6Gg as in the above-mentioned embodiment.

In the above-described embodiment and modified examples, the cup 16 is one example of a gas-liquid separating member. The gas-liquid separating member faces both the refrigerant inlet hole 8 and the refrigerant outlet hole 9. The gas-liquid separating member has a portion with which the refrigerant that flows in from the refrigerant inlet hole 8 collides. The gas-liquid separating member preferably faces the entire refrigerant inlet hole 8. The facing direction is the axial direction of the refrigerant inlet hole 8.
The gas-liquid separating member preferably has a top wall facing both the entire refrigerant inlet hole 8 and the refrigerant outlet hole 9 , and a cylindrical side wall facing the inner circumferential surface of the body 3 .
Preferably, the gap between the header 4 and the top wall and the gap between the inner circumferential surface of the body 3 and the side wall are approximately the same. Here, approximately the same means that in addition to being completely the same, it may include an error. That is, when the refrigerant that flows in from the refrigerant inlet hole 8 collides with the top wall and flows downstream, it flows through the gap between the top wall and the header 4 and the gap between the inner circumferential surface of the body 3 and the side wall. If these gaps are "the same", the smooth flow of the refrigerant is maintained. In addition, even if there is a small error in these gaps, the state in which the refrigerant flows smoothly can be maintained. The error is an error that can maintain the flow of the refrigerant smoothly in this way.
The top wall of the gas-liquid separating member is not limited to being in the form of a plate having a constant thickness.
Furthermore, another example of the gas-liquid separating member has a structure that does not include a side wall.

The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments, and various modifications are possible within the scope of the present invention. For example, in the first and second embodiments, the header and inner pipe are assembled by screwing together the threads, but as in the third and fourth embodiments, the header and inner pipe may be fixed by press fitting, brazing, welding, or the like.

This specification includes the disclosure of the following inventions.
(First aspect)
a body portion having an opening at at least one end;
a header having a refrigerant inlet and a refrigerant outlet, the header closing an opening at one end of the body;
a gas-liquid separating member disposed within the body portion and facing the refrigerant inlet and the refrigerant outlet;
an outflow pipe connected to the refrigerant outflow hole,
the outflow pipe includes a small diameter cylindrical portion that is inserted into and fixed to the refrigerant outflow hole, and a large diameter cylindrical portion that is larger in diameter than the small diameter cylindrical portion and that is disposed within the body portion, and the gas-liquid separating member is sandwiched between the header and a step surface that is an end surface of the large diameter cylindrical portion on the side of the small diameter cylindrical portion,
The outflow pipe has a cylindrical inner circumferential surface formed in the small diameter cylindrical portion, and a tapered inner circumferential surface that is connected to the cylindrical inner circumferential surface and that decreases in diameter toward the refrigerant outflow hole.
1. An accumulator comprising:

(Second embodiment)
The tapered inner peripheral surface extends to an end of the large diameter cylindrical portion on an opposite side to the small diameter cylindrical portion.
10. The accumulator of claim 1,

(Third Form)
The small diameter cylindrical portion is formed in a cylindrical shape and has a male thread on its outer circumferential surface,
The refrigerant outlet hole has an internal thread,
The outflow pipe is fixed to the header by threading the male thread into the female thread.
2. The accumulator according to claim 1,

(Fourth Form)
The small diameter cylindrical portion is fixed to the refrigerant outlet hole of the header by press-fitting, brazing, or welding.
The accumulator according to any one of the first to third aspects,

(Fifth Form)
The accumulator according to any one of the first to fourth forms, characterized in that the inner circumferential surface of the outflow pipe gradually expands in diameter from the vicinity of the end of the outflow pipe away from the refrigerant outflow hole toward the end.

(Sixth Form)
The accumulator according to any one of the first to fourth forms, wherein an outer circumferential surface of the outflow pipe is gradually tapered from a vicinity of an end of the outflow pipe away from the refrigerant outflow hole toward the end.

(Seventh Form)
The accumulator according to any one of the first to fourth forms, wherein an inner circumferential surface of the outflow pipe gradually expands in diameter from the vicinity of the end of the outflow pipe away from the refrigerant outflow hole toward the end, and an outer circumferential surface of the outflow pipe gradually contracts in diameter from the vicinity of the end toward the end.

1 Accumulator 2 Tank body 3 Body 4 Header 5

Double pipe

6, 6A, 6B, 6C, 6D, 6E Inner pipe (outlet pipe)
6F, 6G Outlet pipe 6a, 6Aa Small diameter cylindrical portion 6b, 6Ab Large diameter cylindrical portion 6d, 6Ad Step surface 6f, 6Af Tapered inner peripheral surface 6g, 6Ag1, 6Fg, 6Gg Pressure equalizing hole 7 Outer pipe 8 Refrigerant inlet hole 9 Refrigerant outlet hole 11 Bag 20 Strainer 21 Case 22 Mesh filter

Claims

a body portion having an opening at at least one end;
a header having a refrigerant inlet and a refrigerant outlet, the header closing an opening at one end of the body;
a gas-liquid separating member disposed within the body portion and facing the refrigerant inlet and the refrigerant outlet;
an outflow pipe connected to the refrigerant outflow hole,
the outflow pipe includes a small diameter cylindrical portion that is inserted into and fixed to the refrigerant outflow hole, and a large diameter cylindrical portion that is larger in diameter than the small diameter cylindrical portion and that is disposed within the body portion, the gas-liquid separating member is sandwiched between the header and a step surface that is an end surface of the large diameter cylindrical portion on the side of the small diameter cylindrical portion,
The outflow pipe has a cylindrical inner circumferential surface formed in the small diameter cylindrical portion, and a tapered inner circumferential surface that is connected to the cylindrical inner circumferential surface and that decreases in diameter toward the refrigerant outflow hole.
1. An accumulator comprising:
The tapered inner peripheral surface extends to an end of the large diameter cylindrical portion on an opposite side to the small diameter cylindrical portion.
2. The accumulator of claim 1 .
The small diameter cylindrical portion is formed in a cylindrical shape and has a male thread on its outer circumferential surface,
The refrigerant outlet hole has an internal thread,
The outflow pipe is fixed to the header by threading the male thread into the female thread.
2. The accumulator of claim 1 .
The small diameter cylindrical portion is fixed to the refrigerant outlet hole of the header by press-fitting, brazing, or welding.
2. The accumulator of claim 1 .
An accumulator according to any one of claims 1 to 4, characterized in that the inner circumferential surface of the outflow pipe gradually expands in diameter from the vicinity of the end of the outflow pipe away from the refrigerant outflow hole toward the end.
An accumulator according to any one of claims 1 to 4, characterized in that the outer circumferential surface of the outflow pipe gradually narrows in diameter from the vicinity of the end of the outflow pipe away from the refrigerant outflow hole toward the end.
The accumulator according to any one of claims 1 to 4, characterized in that an inner circumferential surface of the outflow pipe gradually expands in diameter from a vicinity of an end of the outflow pipe away from the refrigerant outflow hole toward the end, and an outer circumferential surface of the outflow pipe gradually contracts in diameter from a vicinity of the end toward the end.