Accumulator

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

[0001] The present invention relates to an accumulator.

[0002] A receiver tank, an accumulator, or the like is used to separate the refrigerant circulating in the refrigeration cycle into gas and liquid and store the separated refrigerant.

[0003] 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 a mist of gas-liquid phase. The depressurized low-pressure refrigerant absorbs heat from air blown by an air conditioner blower in an evaporator and evaporates. As is well known, the air cooled by the evaporator is temperature-adjusted in a heater core (not shown) and then blown into, for example, a vehicle cabin. The refrigerant that passes through the evaporator is separated into gas and liquid in an accumulator and then drawn into the compressor.

[0004] For this reason, the header of the accumulator is formed with a refrigerant inlet and a refrigerant outlet that communicate with the interior 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 separator (cup) that separates the refrigerant flowing through the refrigerant inlet into liquid and gas phases, as disclosed in Patent Document 1.

[0005] JP 2014-52139 A

[0006] In order to improve the performance of the refrigeration cycle, there is a demand for increasing the amount of refrigerant passing through the accumulator. One idea for increasing the amount of refrigerant passing through the accumulator is to use an outflow pipe with a large inner diameter that is disposed inside the accumulator and connected to the refrigerant outlet of the header.

[0007] However, the diameter of the refrigerant outlet formed in the header is determined by the piping that forms the flow path downstream of the accumulator, and this piping is often designed by the manufacturer that assembles the refrigeration cycle. As such, the specifications of the refrigerant outlet of the accumulator are determined by the designed piping size, which makes it difficult to use an outflow pipe with a large inner diameter regardless of the size of the piping connected to it.

[0008] In response to this problem, it is possible to use an outflow pipe with a partially enlarged diameter, but this has the following problems. For example, as in Patent Document 1, in the case of an accumulator having a gas-liquid separator (cup) that separates the liquid refrigerant from the gas refrigerant inlet, 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 being gripped between the flange and the header. Because of this bulging, a pipe member is used as the outflow pipe, which makes it difficult to use an outflow pipe with a partially enlarged diameter.

[0009] The present invention has been made in consideration of such problems, and aims to provide an accumulator that can retain a gas-liquid separator and increase the amount of refrigerant passing through while preventing an increase in the number of parts.

[0010] In order to achieve the above object, the accumulator of the present invention comprises: a body portion having an opening at at least one end; a header having a refrigerant inlet hole and a refrigerant outlet hole and closing the opening at one end of the body portion; a gas-liquid separating member arranged within the body portion opposite the refrigerant inlet hole and the refrigerant outlet hole; and an outlet pipe connected to the refrigerant outlet hole, wherein the outlet pipe comprises a small-diameter cylindrical portion inserted into and fixed to the refrigerant outlet hole, and a large-diameter cylindrical portion having a diameter larger than that of the small-diameter cylindrical portion and arranged within the body portion, the gas-liquid separating member being sandwiched between a step surface that is an end face of the large-diameter cylindrical portion facing the small-diameter cylindrical portion and the header, and the outlet 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 decreases in diameter toward the refrigerant outlet hole.

[0011] According to the present invention, it is possible 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.

[0012] FIG. 1 is a longitudinal cross-sectional view of an accumulator according to a first embodiment. FIG. 2 is a cross-sectional view showing a header, a cup, and an inner pipe in an exploded state. FIG. 3 is a longitudinal cross-sectional view of an accumulator according to a second embodiment. FIG. 4 is a longitudinal cross-sectional view of an inner pipe according to the second embodiment. FIG. 5 is a cross-sectional view showing an enlarged view of the lower end of the inner pipe of this embodiment. FIG. 6 is a cross-sectional view showing an enlarged view of the lower end of an inner pipe according to a first modified example. FIG. 7 is a cross-sectional view showing an enlarged view of the lower end of an inner pipe according to a second modified example. FIG. 8 is a cross-sectional view showing an enlarged view of the lower end of an inner pipe according to a third modified example. FIG. 9 is a longitudinal cross-sectional view of an inner pipe according to a third embodiment. FIG. 10 is a longitudinal cross-sectional view of an inner pipe according to a fourth embodiment.

[0013] Hereinafter, an accumulator 1 according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0014] 1 is a longitudinal 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 includes a tank body 2, a double pipe 5 disposed within the tank body 2, a bag 11 containing a desiccant (moisture absorbent) DA, a cup (also referred to as a gas-liquid separating member) 16, and a strainer 20.

[0015] The tank body 2 is composed of a cylindrical body 3 having an open top end and a bottom, and a header 4 joined to the body 3 by a circumferential weld 10 to close the opening of the body 3. The body 3 is a barrel portion having an opening at at least one end. Both the body 3 and the header 4 are formed of 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 and open 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 closing the other opening of the body 3 is formed of a metal such as an aluminum alloy.

[0016] The header 4 is formed in a roughly disk shape and has a refrigerant inlet hole 8 and a refrigerant outlet hole 9 formed therethrough from top to bottom. An inner pipe (also called an outlet pipe) 6 extending to near 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, thereby forming a double pipe 5.

[0017] A cup 16 is provided below the header 4 as a gas-liquid separator that separates the mixed refrigerant (a refrigerant containing a mixture of gas and liquid phases) from the refrigerant inlet 8 into a high-density liquid-phase refrigerant and compressor oil (hereinafter referred to as "oil"), and a low-density gas-phase refrigerant. The cup 16 has a cylindrical shape with a top and is disposed opposite the refrigerant inlet 8 and the refrigerant outlet 9.

[0018] The inner pipe 6 is made of a metal such as an aluminum alloy, has an open lower end, and, as will be described later, has an upper end connected to a refrigerant outlet hole 9 of the header 4. The outer periphery of the inner pipe 6 is fitted into a plurality 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.

[0019] The outer pipe 7 is made of synthetic resin and is attached to the inside of 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 made of synthetic resin and having a bottom, and a cylindrical mesh filter 22 that is integrated with the case 21 by insert molding or the like.

[0020] A bag 11 containing a desiccant DA is disposed between the outer pipe 7 and the inner periphery of the body 3.

[0021] 2 is a cross-sectional view showing the header 4, cup 16, and inner pipe 6 in an exploded state. The header 4 has a large cylindrical portion 4a and a step portion 4c 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, as a plane perpendicular to the up-down direction.

[0022] 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, vertically penetrating the header 4, and a refrigerant inlet hole 8 is formed adjacent to the boss 4d, vertically penetrating the header 4. The underside of the boss 4d is formed, for example, as a flat surface that is in surface contact with the upper surface of a top wall 16b of a cup 16, which will be described later. The underside of the boss 4d is formed, for example, as a flat surface that is perpendicular to the axis of the inner pipe 6.

[0023] The refrigerant outlet hole 9 has a large diameter hole 9a formed in an upper portion and a female thread 9b formed in a lower portion. The inner diameter of the large diameter hole 9a is larger than the root diameter of the female thread 9b.

[0024] 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 an upwardly protruding shape. The ribs 16b1 constitute part of the upper surface of the top wall. The area of ​​the upper surface of the top wall 16b of the cup 16 that abuts against the lower surface of the boss 4d of the header 4 is formed as a plane that makes surface contact with the lower surface of the boss 4d. The area of ​​the upper surface of the top wall 16b of the cup 16 that abuts against the lower surface of the boss 4d of the header 4 is formed as a plane that is perpendicular to the axis of the inner pipe 6. Alternatively, a portion of the rib 16b1 may be formed on the upper surface of the top wall 16b of the cup 16 that abuts against the lower surface of the boss 4d of the header 4. In this configuration, a recess is formed in the lower surface of the boss 4d of the header 4 to accommodate part of the rib 16b1. The recess has a shape that allows the rib 16b1 to fit in. The lower surface of the top wall 16b is formed as a flat surface that comes into surface contact with a stepped surface 6d of the inner pipe (described later), and is formed as a flat surface that is perpendicular to the axis of the inner pipe.

[0025] The top wall 16b faces both the refrigerant inlet 8 and the refrigerant outlet 9. The top wall 16b is the area where the refrigerant flowing through the refrigerant inlet 8 collides. The top wall 16b faces the entire refrigerant inlet 8. The opposing direction is the axial direction of the refrigerant inlet 8. 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 substantially the same. Here, "substantially the same" does not necessarily mean "completely the same" but may also include a margin of error. That is, when the refrigerant flowing through the refrigerant inlet 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. Having these gaps "the same" maintains a smooth refrigerant flow. Even if there is a small margin of error in these gaps, the refrigerant can still flow smoothly. The margin of error is thus sufficient to maintain a smooth refrigerant flow.

[0026] The inner pipe 6 is formed, for example, by cutting an aluminum material, and comprises a small-diameter cylindrical portion (also referred to as the small-diameter cylindrical portion) 6a that is inserted into and fixed in the refrigerant outflow hole 9, and a large-diameter cylindrical portion (also referred to as the large-diameter cylindrical portion) 6b that has a larger diameter than the small-diameter cylindrical portion 6a and is disposed 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 that of the through-hole 16c.

[0027] 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 is formed between the small-diameter cylindrical portion 6a and the large-diameter cylindrical portion 6b, facing the refrigerant outflow hole 9. 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.

[0028] Furthermore, the inner pipe 6 has a cylindrical inner circumferential surface 6e extending within the small-diameter cylindrical portion 6a, and a tapered inner circumferential surface 6f on the lower end side that connects to the cylindrical inner circumferential surface 6e near the step surface 6d. The tapered inner circumferential surface 6f, which decreases in diameter toward the cylindrical inner circumferential surface 6e (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 circumferential surface 6f extends to the vicinity of the lower end of the inner pipe, the tapered inner circumferential surface 6f and the lower end can be connected by another cylindrical inner circumferential surface. It is preferable that the taper angle θ of the tapered inner circumferential surface 6f is uniform and is equal to or greater than 10 degrees.

[0029] 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 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.

[0030] 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, around the through-hole 16c. Note that, for example, the rib 16b1 is formed on the upper surface of the top wall 16b 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 into contact with the cup 16 from below. The small-diameter cylindrical portion 6a of the inner pipe 6 is then inserted into the through-hole 16c, and the male thread 6c is screwed into the female thread 9b of the header 4.

[0031] Thereafter, when the male thread 6c is threaded onto the female thread 9b, the inner pipe 6 approaches the header 4, and the stepped surface 6d abuts against the underside of the cup 16 around the through-hole 16c. The underside of the top wall 16b of the cup 16 makes surface contact with the stepped surface 6d. At this time, the cup 16 is sandwiched and fixed between the lower end of the boss 4d and the stepped surface 6d. Compared to bulging, the flatness of the stepped surface 6d is ensured to be higher. Therefore, even if the area of ​​the stepped surface 6d is small, the cup 16 can be held in an appropriate position by making surface contact with the underside of the cup 16. The outer pipe 7 and strainer 20 are assembled to the inner pipe 6, and the assembly is installed in the body 3 in which the bag 11 is disposed, and then welded to the header 4 to complete the accumulator 1.

[0032] According to this embodiment, the small-diameter cylindrical portion 6a is formed to fit the refrigerant outflow hole 9 of the header 4, and the 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 sandwich 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.

[0033] According to this embodiment, the inner pipe 6 is fastened to the header 4 by threading the female threads 9b into the male threads 6c, eliminating the need for crimping the inner pipe 6 as was conventionally done (no crimped 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 a 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 refrigerant.

[0034] 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 bulging or other processes on the inner pipe 6. This reduces the resistance of the refrigerant flowing through the inner pipe 6, suppresses the occurrence of turbulence, and ensures a smooth flow of the refrigerant.

[0035] In addition, according to this embodiment, the inner pipe 6 is formed with a tapered inner circumferential surface 6f, and the inner diameter is gradually reduced 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.

[0036] The operation of the accumulator 1 configured as above will be described with reference to Fig. 1. In the following description, an example will be described in which the accumulator 1 is disposed between the evaporator and compressor of a refrigeration cycle, and moisture contained in the refrigerant from the evaporator is removed to generate gas refrigerant, which is then returned to the compressor.

[0037] 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 vapor-phase refrigerant (gas refrigerant).

[0038] 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 where a portion of the desiccant-containing bag 11 is immersed. Therefore, both the water content in the liquid refrigerant and the moisture content in the gas refrigerant are absorbed by the desiccant DA.

[0039] On the other hand, the gas-phase refrigerant after gas-liquid separation flows in from the upper end opening of the outer pipe 7 and flows down inside the outer pipe 7. Then, the refrigerant turns back at the bottom of the outer pipe 7, flows over the lower end of the inner pipe 6, and then rises inside the inner pipe 6 to be guided to the refrigerant outlet hole 9.

[0040] The oil that accumulates in the lower part of the body 3 together with the liquid refrigerant moves toward the bottom 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 drawn into the compressor suction side. It passes through the mesh filter 22 of the strainer 20, the oil return hole 7e, and the inner space of the inner pipe 6, in that order, and is 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).

[0041] Second Embodiment Fig. 3 is a vertical cross-sectional view of an accumulator 1A according to a second embodiment, but similar to Fig. 1, only the left half of the strainer is shown in cross section. 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.

[0042] In this embodiment, only the inner pipe 6A is different from the first embodiment, and the other configurations are the same as those in the first embodiment, so the same reference numerals are used for the common configurations and redundant explanations will be omitted.

[0043] The inner pipe 6A of this embodiment is formed by forging an aluminum material, for example, and comprises 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.

[0044] 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 near the step surface 6Ad. The step surface 6Ad is perpendicular to the axis L of the inner pipe 6A.

[0045] The inner pipe 6A has a first cylindrical inner circumferential surface 6Ae at its upper end, a tapered inner circumferential surface 6Af at its lower end 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 greater when formed by forging.

[0046] In this embodiment, the second cylindrical inner circumferential surface 6Ag maintains a cylindrical shape up to the lower end 6Ah of the inner pipe 6A, and the outer circumferential surface of the large-diameter cylindrical portion 6Ab also maintains a cylindrical shape. Furthermore, the lower end 6Ah is an end face perpendicular to the axis L (see FIG. 5).

[0047] In this embodiment, too, 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, thereby assembling the cup 16, which is clamped and fixed between the lower end of the boss 4d and the step surface 6Ad.

[0048] (Variation 1) Figure 6 is an enlarged cross-sectional view showing the lower end of the inner pipe 6B according to Variation 1. In this variation, the outer peripheral 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 peripheral surface 6Bg gradually increases in diameter from the vicinity of the lower end 6Bh toward the lower end 6Bh and intersects with the outer peripheral surface of the large-diameter cylindrical portion 6Bb at the lower end 6Bh. In the cross section shown in Figure 6, the second cylindrical inner peripheral surface 6Bg near the lower end 6Bh preferably has an arc shape.

[0049] Referring to Figure 1, according to this modified example, when the gas-liquid separated gas-phase refrigerant turns back 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 second cylindrical inner surface 6Bg, which gradually expands in diameter, thereby ensuring a smooth flow of the refrigerant.

[0050] (Variation 2) Figure 7 is an enlarged cross-sectional view showing the lower end of an inner pipe 6C according to Variation 2. In this variation, 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 Figure 7, the outer circumferential surface of the large-diameter cylindrical portion 6Cb near the lower end 6Ch preferably has an arc shape.

[0051] Referring to FIG. 1, according to this modified example, when the gas-liquid separated gas-phase refrigerant is turned back 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, thereby ensuring a smooth flow of the refrigerant.

[0052] (Variation 3) Figure 8 is an enlarged cross-sectional view showing the lower end of an inner pipe 6D according to Variation 3. In this variation, the second cylindrical inner circumferential surface 6Dg gradually increases 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, so that 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 Figure 8, it is preferable that the lower end wall of the large-diameter cylindrical portion 6Cb near the lower end 6Ch has a semicircular arc shape.

[0053] Referring to Figure 1, according to this modified example, when the gas-liquid separated gas-phase refrigerant turns back at the bottom of the outer pipe 7 and heads toward the lower end 6Dh of the inner pipe 6D, it flows along the outer surface of the gradually narrowed large-diameter cylindrical portion 6Db, and when it passes the lower end 6Dh of the inner pipe 6D and flows inward, it flows along the gradually enlarged second cylindrical inner surface 6Dg, thereby ensuring a smooth flow of the refrigerant.

[0054] Modifications 1 to 3 are similarly applicable to the inner pipe 6 in the first embodiment.

[0055] Third Embodiment Fig. 9 is a longitudinal cross-sectional view of an accumulator 1F according to a third embodiment. The accumulator 1F of this embodiment has a U-shaped outflow pipe 6F and does not have an outer pipe. Note that Fig. 9 omits the strainer, the bag containing the desiccant, and the like. In this embodiment, the configuration of the header 4F and the outflow pipe 6F differs from that of the above-described embodiment, but the other configuration is the same as that of the above-described embodiment. Therefore, the same reference numerals are used to designate common components, and redundant description will be omitted.

[0056] In the header 4F of this embodiment, the refrigerant outlet holes 9F do not have female threads, but have large diameter holes 9Fa and small diameter holes 9Fb. The rest of the configuration is the same as in the above-described embodiment.

[0057] The outflow pipe 6F of this embodiment is formed by connecting a small-diameter cylindrical portion 6Fa and a large-diameter U-shaped cylindrical portion 6Fb that is bent into a U. The small-diameter cylindrical portion 6Fa does not have a male thread on its outer peripheral surface 6Fc, and has an outer diameter that is approximately the same as the inner diameter of the small-diameter hole 9Fb.

[0058] 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, thereby forming a step surface 6Fd 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, similar to the above-described embodiment.

[0059] In this embodiment, after the cup 16 is placed 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 sandwiched and fixed between the lower end of the boss 4Fd and the stepped surface 6Fd.

[0060] According to this embodiment, the outflow pipe 6F can be attached by moving it linearly relative to the header 4 without rotating it, so that the free end of the outflow pipe 6F can be positioned within the cup 16 in the assembly position shown in Figure 9.

[0061] (Fourth embodiment) Figure 10 is a longitudinal cross-sectional view of an accumulator 1G according to a fourth embodiment. The accumulator 1G of this embodiment differs 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 remaining configuration is the same as in the above-described embodiments. Furthermore, the outflow pipe 6G has a pressure equalizing hole 6Gg, as in the above-described embodiments.

[0062] In the above-described embodiment and modified examples, the cup 16 is an example of a gas-liquid separating member. The gas-liquid separating member faces both the refrigerant inlet 8 and the refrigerant outlet 9. The gas-liquid separating member has a portion against which the refrigerant flowing in through the refrigerant inlet 8 impinges. The gas-liquid separating member preferably faces the entire refrigerant inlet 8. The opposing direction is the axial direction of the refrigerant inlet 8. The gas-liquid separating member preferably has a top wall facing both the entire refrigerant inlet 8 and the refrigerant outlet 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 substantially the same. Here, "substantially the same" means that they are completely the same, but may also include some error. In other words, when the refrigerant flowing in through the refrigerant inlet 8 impinges on 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. When these gaps are "equal," the smooth flow of the refrigerant is maintained. In addition, even if there is a slight error in these gaps, the smooth flow of the refrigerant can be maintained. The error is thus an error that can maintain the smooth flow of the refrigerant. The top wall of the gas-liquid separating member is not limited to a plate-like shape with a constant thickness. Furthermore, another example of a gas-liquid separating member has a structure that does not have a side wall.

[0063] While the present invention has been described above with reference to the embodiments, 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 threading together, but as in the third and fourth embodiments, the header and inner pipe may be fixed by press-fitting, brazing, welding, or the like.

[0064] This specification includes the following disclosure: (First Aspect) An accumulator comprising: a body portion having an opening at at least one end; a header having a refrigerant inlet hole and a refrigerant outlet hole and closing the opening at one end of the body portion; a gas-liquid separating member disposed within the body portion facing the refrigerant inlet hole and the refrigerant outlet hole; and an outflow pipe connected to the refrigerant outlet hole, wherein the outflow pipe has a small-diameter cylindrical portion inserted into and fixed to the refrigerant outlet hole, and a large-diameter cylindrical portion having a diameter larger than that of the small-diameter cylindrical portion and disposed within the body portion, the gas-liquid separating member being sandwiched between the header and a stepped surface that is an end face of the large-diameter cylindrical portion facing the small-diameter cylindrical portion, and 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 that reduces in diameter toward the refrigerant outlet hole.

[0065] (Second Mode) The accumulator according to the first mode, wherein the tapered inner peripheral surface extends to an end of the large-diameter cylindrical portion on the opposite side to the small-diameter cylindrical portion.

[0066] (Third Mode) The accumulator of the second mode, characterized in that the small-diameter cylindrical portion is formed in a cylindrical shape and has a male thread on its outer circumferential surface, the refrigerant outflow hole has a female thread, and the outflow pipe is fixed to the header by screwing the male thread into the female thread.

[0067] (Fourth Mode) The accumulator according to any one of the first to third modes, wherein the small-diameter cylindrical portion is fixed to the refrigerant outlet hole of the header by press-fitting, brazing, or welding.

[0068] (Fifth Mode) The accumulator according to any one of the first to fourth modes, wherein 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.

[0069] (Sixth Mode) The accumulator according to any one of the first to fourth modes, wherein the outer peripheral surface of the outflow pipe gradually reduces in diameter from a vicinity of an end of the outflow pipe away from the refrigerant outflow hole toward the end.

[0070] (Seventh Mode) The accumulator according to any one of the first to fourth modes, wherein the inner circumferential surface of the outflow pipe gradually increases in diameter from a vicinity of an end of the outflow pipe away from the refrigerant outflow hole toward the end, and the outer circumferential surface of the outflow pipe gradually decreases in diameter from a vicinity of the end toward the end.

[0071] REFERENCE SIGNS LIST 1 accumulator 2 tank body 3 trunk 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 circumferential 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

1. 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 has a cylindrical structure including a small-diameter cylindrical portion inserted and fixed in the refrigerant outflow hole, a large-diameter cylindrical portion having a diameter larger than that of the small-diameter cylindrical portion and disposed within the body portion, and at least one stepped surface extending in a radial direction, the gas-liquid separating member being sandwiched between the stepped surface, which is an end surface of the large-diameter cylindrical portion on the side of the small-diameter cylindrical portion, and the header; 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:

2. 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 .

3. 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 a female thread, The outflow pipe is fixed to the header by threading the male thread into the female thread.

2. The accumulator of claim 1 .

4. 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 .

5. 5. The accumulator according to claim 1, wherein an inner circumferential surface of the outflow pipe is gradually enlarged in diameter from a vicinity of an end of the outflow pipe away from the refrigerant outflow hole toward the end.

6. 5. The accumulator according to claim 1, 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.

7. 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.