Accumulator and method for manufacturing same

Abstract

Provided are an accumulator with which it is possible to increase an amount of refrigerant that passes through the accumulator, and a method for manufacturing the same.　In the accumulator, an outflow pipe includes a small cylindrical portion which is inserted into and fixed to a refrigerant outflow hole, a large cylindrical portion which is disposed within a body portion and which has a cross-sectional area greater than that of the small cylindrical portion, and a tapered cylindrical portion connecting the small cylindrical portion and the large cylindrical portion, wherein: an inner circumferential surface of the outflow pipe has, along a refrigerant flow direction, a large inner circumferential surface, an intermediate inner circumferential surface connected to the large inner circumferential surface, and a small inner circumferential surface which is connected to the intermediate inner circumferential surface and which has a cross-sectional area smaller than the cross-sectional area of the large inner circumferential surface; the intermediate inner circumferential surface has a shape having a cross-sectional area that gradually decreases toward the small inner circumferential surface side; a gas-liquid separating member includes a main body that has a communicating portion and that faces a header, and an extension portion that extends from the main body to the tapered cylindrical portion; and the extension portion is sandwiched between the header and the outflow pipe in a state in which the extension part is in contact with the tapered cylindrical portion.

Description

Accumulator and manufacturing method thereof

[0001] The present invention relates to an accumulator and a method for manufacturing the same.

[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] In the refrigeration cycle, high-pressure gas-phase refrigerant discharged from the compressor flows into the condenser, where it exchanges heat with outside air and is cooled and condensed. 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 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, for example, the passenger compartment. 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 purpose, 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.

[0005] 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.

[0006] JP 2014-52139 A

[0007] 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.

[0008] 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.

[0009] The present invention has been made in view of the above problems, and has an object to provide an accumulator that can increase the amount of refrigerant passing through, and a method for manufacturing the same.

[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 one end of the body portion; a gas-liquid separating member housed within the body portion, the gas-liquid separating member having a communication part formed in a part facing the refrigerant outlet hole that communicates the header side with the opposite side; and an outflow pipe housed within the body portion, a part of which is disposed in the communication part and connected to the refrigerant outlet hole, the outflow pipe having a small cylinder part inserted into and fixed in the refrigerant outlet hole, a large cylinder part disposed within the body portion and having a cross-sectional area larger than that of the small cylinder part, and a tapered cylinder part connecting the small cylinder part and the large cylinder part, The inner surface of the outflow pipe has, along the flow direction of the refrigerant, a large inner surface, an intermediate inner surface connected to the large inner surface, and a small inner surface connected to the intermediate inner surface and having a cross-sectional area smaller than that of the large inner surface, and the intermediate inner surface has a shape in which the cross-sectional area gradually decreases toward the small inner surface; and the gas-liquid separating member has the communicating portion, a main body facing the header, and an extension portion extending from the main body to the tapered cylindrical portion, and is clamped between the header and the outflow pipe with the extension portion abutting the tapered cylindrical portion.

[0011] In order to achieve the above object, the present invention provides a method for manufacturing an accumulator having: a header with a refrigerant outflow hole; an outflow pipe connected to the refrigerant outflow hole; and a gas-liquid separating member arranged opposite the header and having a communication portion through which a portion of the outflow pipe is arranged, the method comprising: forming the outflow pipe having a small cylindrical portion, a large cylindrical portion having a cross-sectional area larger than that of the small cylindrical portion, and a tapered cylindrical portion connecting the small cylindrical portion and the large cylindrical portion by applying a drawing or a tube expansion process to a pipe; forming an extension portion extending in a direction away from the main body portion of the gas-liquid separating member that is arranged opposite the header; with the small cylindrical portion of the outflow pipe arranged in the communication portion, bringing the extension portion and the tapered cylindrical portion close to each other so that the extension portion abuts against the tapered cylindrical portion; and sandwiching the gas-liquid separating member between the header and the outflow pipe by fixing the small cylindrical portion to the refrigerant outflow hole of the header and abutting the extension portion against the tapered cylindrical portion.

[0012] According to the present invention, it is possible to provide an accumulator that can increase the amount of refrigerant passing through, and a method for manufacturing the same.

[0013] FIG. 1 is a vertical 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 bottom view of the cup. FIG. 4 is a cross-sectional view showing an enlarged lower end of the inner pipe of this embodiment. FIG. 5 is a bottom view of a cup according to a first modified example. FIG. 6 is a vertical cross-sectional view of a cup according to the first modified example. FIG. 7 is a cross-sectional view showing an enlarged lower end of an inner pipe according to a second modified example. FIG. 8 is a cross-sectional view showing an enlarged lower end of an inner pipe according to a third modified example. FIG. 9 is a cross-sectional view showing an enlarged lower end of an inner pipe according to a fourth modified example. FIG. 10 is a vertical cross-sectional view of an accumulator according to a second embodiment. FIG. 11 is a vertical cross-sectional view of an accumulator according to a third embodiment. FIG. 12 is a vertical cross-sectional view of an accumulator according to a fourth embodiment.

[0014] Hereinafter, an accumulator according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0015] 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.

[0016] The tank body 2 includes a body 3 and a header 4. The body 3 is formed in a cylindrical shape with at least an opening at the top end, for example, a bottomed cylindrical shape, and is a body portion having an opening at at least one end. The header 4 closes the opening at one end of the body 3. The header 4 is joined to the body 3 by a circumferential joint, for example, via a weld 10, to close the opening of the body 3. The body 3 and the header 4 are both 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 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 closing the other opening of the body 3 is formed of a metal such as an aluminum alloy.

[0017] For example, the header 4 is formed in a substantially 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.

[0018] A cup 16 is provided below the header 4. The cup 16 separates the mixed refrigerant (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 is made of, for example, a resin. The cup 16 has, for example, a cylindrical shape with a top, and is disposed opposite the refrigerant inlet 8 and the refrigerant outlet 9.

[0019] The inner pipe 6 is made of, for example, metal, such as an aluminum alloy. The inner pipe 6 has an open lower end and, as will be described later, has an upper end that is press-fitted into 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 that protrude from the inner periphery of the outer pipe 7, thereby stably holding the inner pipe 6 within the outer pipe 7 with a gap therebetween.

[0020] The outer pipe 7 is made of, for example, 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 made of synthetic resin with a bottom, and a cylindrical mesh filter 22 integrated with the case 21 by insert molding or the like. The strainer 20 may be in contact with, for example, the bottom surface of the internal space of the body 3. When the strainer 20 is in contact with the bottom surface of the internal space of the body 3, the cup 16 is sandwiched between the body 3 and the header 4 via the inner pipe 6.

[0021] A bag 11 containing a desiccant DA is disposed between the outer pipe 7 and the inner periphery of the body 3.

[0022] Fig. 2 is a cross-sectional view showing an exploded state of the header 4, the cup 16, and the inner pipe 6. Fig. 3 is a bottom view of the cup 16. The axis of the inner pipe 6 is designated by L.

[0023] 2, the header 4 is formed by stacking a large cylindrical portion 4a and a thin-walled annular portion 4b having a smaller diameter than the large cylindrical portion 4a, and a step 4c is formed between the large cylindrical portion 4a and the thin-walled annular portion 4b, 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.

[0024] 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 L of the inner pipe 6.

[0025] The refrigerant outlet hole 9 has a large diameter hole 9a formed in an upper portion and a small diameter hole 9b formed in a lower portion. The inner diameter of the large diameter hole 9a is larger than the inner diameter of the small diameter hole 9b.

[0026] The cup 16 has a cup main body (also simply referred to as the main body) 16e and an extension 16d. The cup main body 16e faces the header 4 within the body 3. The cup main body 16e is formed by connecting a side wall 16a and a top wall 16b. A through hole 16c is formed in the top wall 16b. The through hole 16c is an example of a communication portion through which a portion of the inner pipe 6 is disposed. The communication portion is formed in a shape that communicates the header 4 side with the opposite side of the cup main body 16e, in other words, the bottom side of the body 3. The communication portion is not limited to a through hole. In another example, the communication portion may be a notch that penetrates the cup main body 16e and opens to the side of the cup main body 16e. For example, one or more ribs 16b1 are formed on the upper surface of the top wall 16b so as to protrude upward. The ribs 16b1 constitute part of the upper surface of the top wall.

[0027] On the underside of the top wall 16b, extension portions 16d are formed around the through hole 16c, for example, on the edge of the through hole 16c. The extension portions 16d are formed in a shape that extends from the cup body 16e to the tapered cylindrical portion 6c and abuts against the tapered cylindrical portion 6c of the inner pipe 6. Multiple extension portions 16d, for example, four extension portions 16d, are formed. As an example, the extension portions 16d are formed in a wall shape. In this embodiment, the extension portions 16d will be described as retaining walls 16d. The four retaining walls 16d are arranged, for example, at equal intervals on the edge of the through hole 16c. The retaining walls 16d are formed to be continuous with the cup body 16e. The underside of the top wall 16b, excluding the retaining walls 16d, is flat.

[0028] 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.

[0029] The retaining wall 16d has, for example, a shape corresponding to the inner pipe 6. Here, the corresponding shape means a shape that follows the outer peripheral surface of the inner pipe 6, that is, the surface of the retaining wall 16d that faces and abuts against the inner pipe 6 is formed to have the same shape as or approximately the same shape as the outer peripheral surface of the inner pipe 6.

[0030] The retaining wall 16d has a shape that is point-symmetrical with respect to the axis of the through hole 16c (which coincides with the axis L when assembled), and specifically consists of a rectangular plate-shaped base 16d1 on the top wall 16b side, a rectangular plate-shaped tip 16d2 on the lower end side, and a right-angled trapezoidal plate-shaped intermediate portion 16d3 that connects the base 16d1 and the tip 16d2.

[0031] In a cross section passing through the axis of the through hole 16c, the outer surfaces of the base portion 16d1, the intermediate portion 16d3, and the tip portion 16d2 away from the axis of the through hole 16c are, for example, parallel to the axis of the through hole 16c.

[0032] The distances between the inner surfaces of the base 16d1 and tip 16d2 near the axis of the through hole 16c and the axis of the through hole 16c are R1 and R2, respectively, where R1 < R2. That is, the inner surface of the base 16d1 has the same shape or approximately the same shape as a portion of the outer surface of a cylinder with a radius R1. The inner surface of the tip 16d2 has the same shape or approximately the same shape as a portion of the outer surface of a cylinder with a radius R2. Therefore, the inner surface of the intermediate portion 16d3 near the axis of the through hole 16c is inclined at an angle θ1 with respect to the axis of the through hole 16c. The inner surface of the intermediate portion 16d3 has the same shape or approximately the same shape as a portion of the outer surface of a truncated cone with a radius R2 at the bottom and a radius R1 at the top. The inner diameters of the small-diameter hole 9b and the through hole 16c are 2 × R1.

[0033] The area of ​​the upper surface of the top wall 16b of the cup 16 that comes into contact with the lower surface of the boss 4d of the header 4 is formed as a plane that comes into 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 comes into contact with 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, for example. Alternatively, a portion of the rib 16b1 may be formed on the upper surface of the top wall 16b of the cup 16 in the area that comes into contact with 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 a portion of the rib 16b1. This recess has a shape that allows the rib 16b1 to fit into, for example.

[0034] The inner pipe 6 is composed of a small-diameter cylindrical portion (also called a small cylinder portion) 6a that is inserted into and fixed in the small-diameter hole 9b of the refrigerant outflow hole 9, and a large-diameter cylindrical portion (also called a large cylinder portion) 6b that is larger in diameter than the small-diameter cylindrical portion 6a and is placed inside the body 3, and these are connected by a tapered cylindrical portion 6c.

[0035] The inner pipe 6 is formed by drawing a pipe made of, for example, metal, such as aluminum. The outer diameter of the small-diameter cylindrical portion 6a is smaller than the outer diameter of the large-diameter cylindrical portion 6b, but by drawing the pipe, the fiber flow in the metal structure of the inner pipe 6 is continuous from the small-diameter cylindrical portion 6a to the tapered tubular portion 6c and the large-diameter cylindrical portion 6b. This continuous fiber flow can be visually confirmed by cutting the inner pipe 6 in the axial direction, and is therefore so-called visible.

[0036] The outer circumferential radii of the small-diameter cylindrical portion 6a and the large-diameter cylindrical portion 6b are r1 and r2, respectively. r1 is equal to R1, or approximately equal to R1. "R1 is approximately equal to R1" includes cases where r1 is smaller than R1 and cases where r1 is larger than R1. r2 is equal to R2, or approximately equal to R2. "R2 is approximately equal to R2" includes cases where r2 is smaller than R2 and cases where r2 is larger than R2.

[0037] The outer peripheral surface of the tapered cylindrical portion 6c is a truncated cone outer peripheral surface with a radius of r2 at the lower end and a radius of r1 at the upper end, or a curved surface substantially similar to the truncated cone outer peripheral surface with a radius of r2 at the lower end and a radius of r1 at the upper end.

[0038] Furthermore, the inner pipe 6 has a small-diameter inner circumferential surface (small inner circumferential surface) 6e extending within the small-diameter cylindrical portion 6a, a tapered inner circumferential surface (intermediate inner circumferential surface) 6f extending within the tapered tubular portion 6c, and a large-diameter inner circumferential surface (large inner circumferential surface) 6g extending within the large-diameter cylindrical portion 6b. Because the refrigerant flows from the lower end to the upper end within the inner pipe 6, the large-diameter inner circumferential surface 6g, the tapered inner circumferential surface 6f, and the small-diameter inner circumferential surface 6e are arranged in this order along the refrigerant flow direction. Because the inner pipe 6 is formed by drawing, the small-diameter inner circumferential surface 6e, the tapered inner circumferential surface 6f, and the large-diameter inner circumferential surface 6g are smoothly connected to one another.

[0039] In a cross section passing through the axis of the through hole 16c, the outer peripheral surface of the tapered cylindrical portion 6c is inclined at an angle θ2 with respect to the axis L of the inner pipe 6. θ2 is equal to θ1 or approximately equal to θ1. The angles θ1 and θ2 are preferably, for example, 40 degrees ± 10 degrees.

[0040] The tapered cylindrical portion 6c abuts against the intermediate portion 16d3 of the retaining wall 16. The outer peripheral surface of the tapered cylindrical portion 6c and the inner peripheral surface of the intermediate portion 16d3 may be formed as curved surfaces that are in surface contact with each other. For example, when r1 is equal to R1 and r2 is equal to R2, the outer peripheral surface of the tapered cylindrical portion 6c is a curved surface that is in surface contact with the inner peripheral surface of the intermediate portion 16d3.

[0041] The tapered cylindrical portion 6c abuts against the intermediate portion 16d3 and the large diameter cylindrical portion 6b abuts against the tip portion 16d2, thereby improving the accuracy of positioning the cup 16 with respect to the inner pipe 6. In other words, the retaining wall 16d is not shaped to abut against the inner pipe 6 at only a single plane, but rather the boundary portions (corners or corners) between the base portion 16d1, the intermediate portion 16d3, and the tip portion 16d2 fit into the boundary portions (corners or corners) between the small diameter cylindrical portion 6e, the tapered cylindrical portion 6c, and the large diameter cylindrical portion 6b of the inner pipe 6, thereby improving the accuracy of positioning the cup 16 with respect to the inner pipe 6.

[0042] Furthermore, if the shape of the tapered tubular portion 6c is not identical to the shape of the inner pipe 6 but is approximately identical, for example if the dimensions are different, it may be the case that the boundary portion between the base 16d1 and intermediate portion 16d3 of the retaining wall 16d does not match the boundary portion between the small diameter cylindrical portion 6e and the tapered tubular portion 6c of the inner pipe 6, or the boundary portion between the intermediate portion 16d3 and tip portion 16d2 of the retaining wall 16d does not match the boundary portion between the tapered tubular portion 6c and the large diameter cylindrical portion 6b of the inner pipe 6. However, even in such cases, the intermediate portion 16d3 of the retaining wall 16d abuts against the tapered tubular portion 6c of the inner pipe 6, and the tip portion 16d2 of the retaining wall 16d abuts against the large diameter cylindrical portion 6b of the inner pipe 6, thereby improving the accuracy of positioning the cup 16 relative to the inner pipe portion 6. Furthermore, the middle portion 16d3 and the tip portion 16d2 of the retaining wall 16d function as a guide when inserting the inner pipe 6 into the refrigerant outlet hole 9 of the header 4, making it easier to fix the inner pipe 6 to the refrigerant outlet hole 9.

[0043] 4 is an enlarged cross-sectional view of the lower end of the inner pipe 6 of this embodiment. The large-diameter inner circumferential surface 6g maintains a cylindrical shape up to the lower end 6h of the inner pipe 6, and the outer circumferential surface of the large-diameter cylindrical portion 6b also maintains a cylindrical shape. Furthermore, the lower end 6h is an end face perpendicular to the axis L.

[0044] 2, a pressure equalizing hole 6q is formed in the tapered cylindrical portion 6c of the inner pipe 6. The pressure equalizing hole 6q penetrates the inside and outside of the inner pipe 6. The pressure equalizing hole 6q is a hole that prevents 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 6q allows not only the liquid-phase refrigerant inside 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.

[0045] (Accumulator Assembly Process) An example of the process for assembling the header 4 formed by cutting or the like, the cup 16 formed from a resin material, and the inner pipe 6 formed by drawing will be described. 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, and the small-diameter hole 9b and the through-hole 16c are aligned approximately coaxially. Note that, on the upper surface of the top wall 16b, the rib 16b1 is formed, for example, in a position that avoids the area where the boss 4d abuts. Therefore, in this embodiment, the lower end of the boss 4d is in surface contact with the flat portion of the upper surface of the top wall 16b.

[0046] Next, the inner pipe 6 is brought close to 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 press-fit into the small-diameter hole 9b of the header 4. The retaining wall 16d also functions to guide the small-diameter cylindrical portion 6a as it enters the small-diameter hole 9b.

[0047] As the small-diameter cylindrical portion 6a is pushed toward the small-diameter hole 9b, the outer peripheral surface of the tapered cylindrical portion 6c abuts and engages with the inner surface of the intermediate portion 16d3 of the retaining wall 16d, locking the inner pipe 6 and preventing it from advancing further toward the header 4. In this state, the tapered cylindrical portion 6c abuts against the intermediate portion 16d3 and the large-diameter cylindrical portion 6b abuts against the tip portion 16d2, improving the accuracy of positioning the cup 16 relative to the inner pipe 6. This allows the cup 16 to be held in an appropriate posture.

[0048] 1, the small-diameter cylindrical portion 6a is supported by abutting against the inner surfaces of the base portions 16d1 of the four retaining walls 16d except for the portion press-fitted into the small-diameter hole 9b. The outer peripheral surface of the tapered tubular portion 6c is supported by abutting against the inner surfaces of the intermediate portions 16d3 of the four retaining walls 16d. Furthermore, the outer peripheral surface of the upper end of the large-diameter cylindrical portion 6b is supported by abutting against the inner surfaces of the tip portions 16d2 of the four retaining walls 16d. This allows the inner pipe 6 to be firmly held against the header 4 and the cup 16, thereby suppressing vibrations and the like.

[0049] The outer pipe 7 and strainer 20 are attached to the inner pipe 6 of the assembly formed in this manner, and the assembly is then installed inside the body 3 in which the bag 11 is disposed, and then welded to the header 4 to complete the accumulator 1. Unless otherwise specified, the order of the above steps is not limited to the order described.

[0050] In the above example, the small diameter cylindrical portion 6a of the inner pipe 6 is inserted into the small diameter hole 9b of the header 4, while the tapered cylindrical portion 6c of the inner pipe 6 and the intermediate portion 16d3 of the retaining wall 16d are brought closer together, so that the small diameter cylindrical portion 6a of the inner pipe 6 is fixed to the small diameter hole 9b of the header 4 and the tapered cylindrical portion 6c of the inner pipe 6 is brought into contact with the intermediate portion 16d3 of the retaining wall 16d, thereby sandwiching the cup 16 between the inner pipe 6 and the header 4. In this way, the operation of bringing the tapered cylindrical portion 6c of the inner pipe 6 and the intermediate portion 16d3 of the retaining wall 16d closer together and the operation of inserting the small diameter cylindrical portion 6a of the inner pipe 6 into the small diameter hole 9b of the header 4 and fixing the small diameter cylindrical portion 6a to the small diameter hole 9b do not necessarily have to be performed simultaneously. In another example, the cup 16 may be clamped between the inner pipe 6 and the header 4 by inserting the small diameter cylindrical portion 6a of the inner pipe 6 into the through hole 16c, bringing the tapered cylindrical portion 6c and the intermediate portion 16d3 closer together and abutting the tapered cylindrical portion 6c and the intermediate portion 16d3, and then, while maintaining this abutting state, inserting the small diameter cylindrical portion 6a into the small diameter hole 9b and fixing the small diameter cylindrical portion 6a to the small diameter hole 9b.

[0051] 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, the cup 16 can be fixed to the header 4 using the inner pipe 6. Therefore, 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.

[0052] According to this embodiment, the inner pipe 6 is fixed to the header 4 by press-fitting the small-diameter cylindrical portion 6a into the small-diameter hole 9b, which eliminates the need for crimping the inner pipe 6, for example (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 a step inside the refrigerant outflow hole 9. This allows the inner diameter of the small-diameter cylindrical portion 6a to be expanded regardless of the inner diameter of the refrigerant outflow hole 9, reducing pressure loss inside the inner pipe 6 and ensuring smooth refrigerant flow.

[0053] Furthermore, according to this embodiment, the cup 16 is attached to the header 4 by sandwiching it between the tapered cylindrical portion 6c 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.

[0054] Alternatively, a female thread may be formed on the inner periphery of the small-diameter hole 9b, a male thread may be formed on the outer periphery of the small-diameter cylindrical portion 6a, and the inner pipe 6 may be fixed to the header 4 by threading the female thread and the male thread together. The male thread of the small-diameter cylindrical portion 6a is preferably formed by rolling, but may also be formed by cutting. In particular, it is preferable to increase the thickness of the small-diameter cylindrical portion 6a by plastic processing such as drawing so that it becomes a thickness suitable for forming the male thread. In such a case, the thickness of the small-diameter cylindrical portion 6a will be thicker than the thickness of the large-diameter cylindrical portion 6b. Furthermore, the tapered inner periphery 6f and the outer periphery of the tapered tubular portion 6c of the inner pipe 6 are not limited to shapes with a uniform inclination angle with respect to the axis, and any shape that decreases in diameter toward the header 4 will suffice.

[0055] (Operation of Accumulator) 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.

[0056] 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).

[0057] 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.

[0058] 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.

[0059] In this case, 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 small-diameter inner circumferential surface 6e on the refrigerant outlet side, thereby reducing pressure loss and ensuring an even smoother flow of the refrigerant.

[0060] 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).

[0061] (First Modification) Fig. 5 is a bottom view of a cup 16A according to a first modification. Fig. 6 is a longitudinal cross-sectional view of a cup 16A according to the first modification. This modification differs from the above-described embodiment in that, instead of a configuration in which multiple extensions (retaining walls) are provided, the extensions are formed in a cylindrical shape. More specifically, as an extension, a retaining cylinder 16Ad is formed on the underside of the top wall 16b around the through-hole 16c, for example, on the edge of the through-hole 16c. The rest of the configuration is the same as in the above-described embodiment, so a repeated description will be omitted.

[0062] The retaining cylinder 16Ad has a shape that is coaxial or approximately coaxial with the axis L of the through hole 16c, and specifically consists of a cylindrical base portion 16Ad1 on the top wall 16b side, a tip cylindrical portion 16Ad2 on the lower end side, and an intermediate cylindrical portion 16Ad3 that connects the cylindrical base portion 16Ad1 and the tip cylindrical portion 16Ad2.

[0063] The outer diameter of the holding cylinder 16Ad is uniform. The inner radii of the cylindrical base 16Ad1 and the tip cylindrical portion 16Ad2 are R1 and R2, respectively, where R1<R2. The inner periphery of the intermediate cylindrical portion 16Ad3 is inclined at an angle θ1 with respect to the axis of the through hole 16c.

[0064] According to this modification, the entire circumference of the retaining cylinder 16Ad of the cup 16A abuts against the outer peripheral surface of the inner pipe 6. Specifically, the entire circumference of the retaining cylinder 16Ad, except for the portion of the small-diameter cylindrical portion 6a of the inner pipe 6 press-fitted into the small-diameter hole 9b, is supported by abutting against the inner peripheral surface of the cylindrical base portion 16Ad1 of the retaining cylinder 16Ad. The outer peripheral surface of the tapered cylindrical portion 6c is supported by abutting against the inner peripheral surface of the intermediate cylindrical portion 16Ad3. Furthermore, the outer peripheral surface of the upper end of the large-diameter cylindrical portion 6b is supported by abutting against the inner peripheral surface of the tip cylindrical portion 16Ad2. Therefore, the cup 16A is sandwiched between the lower surface of the boss 4d of the header 4 and the outer peripheral surface of the tapered cylindrical portion 6c of the inner pipe 6, providing even more stable support. This allows the cup 16A to be held in an appropriate position. As shown by the dotted line in Figure 6, the outer periphery of the retaining cylinder 16Ad is shaped so that its diameter gradually increases as it approaches the top wall 16b (cross-sectional R-shape), which makes it possible to smooth the flow of refrigerant toward the upper end of the outer pipe 7.

[0065] (Second Modification) Figure 7 is an enlarged cross-sectional view showing the lower end of an inner pipe 6B according to a second modification. In this modification, 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 large-diameter 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 Figure 7, the large-diameter inner circumferential surface 6Bg near the lower end 6Bh preferably has an arc shape.

[0066] 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 gradually expanding large-diameter inner surface 6Bg, thereby ensuring a smooth flow of the refrigerant.

[0067] (Third Modification) Figure 8 is an enlarged cross-sectional view showing the lower end of an inner pipe 6C according to a third modification. In this modification, the large-diameter 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 large-diameter inner circumferential surface 6Cg at the lower end 6Ch. In the cross section shown in Figure 8, the outer circumferential surface of the large-diameter cylindrical portion 6Cb near the lower end 6Ch preferably has an arc shape.

[0068] 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.

[0069] (Fourth Modification) Figure 9 is an enlarged cross-sectional view showing the lower end of an inner pipe 6D according to a fourth modification. In this modification, the large-diameter 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 large-diameter inner circumferential surface 6Dg 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 9, the lower end wall of the large-diameter cylindrical portion 6Cb near the lower end 6Dh preferably has a semicircular arc shape.

[0070] 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 widened large-diameter inner surface 6Dg, thereby ensuring a smooth flow of the refrigerant.

[0071] Second Embodiment Fig. 10 is a longitudinal cross-sectional view of an accumulator 1F according to a second embodiment. In the accumulator 1F of this embodiment, the outflow pipe 6F is U-shaped and does not have an outer pipe. Note that Fig. 10 omits the strainer, the bag containing the desiccant, and the like. In this embodiment, the configuration of the outflow pipe 6F is different from that of the above-described embodiment, but the other configurations are the same as those of the above-described embodiment, so a duplicated description will be omitted.

[0072] The outflow pipe 6F of this embodiment is composed of a small-diameter cylindrical portion 6Fa and a large-diameter U-shaped cylindrical portion 6Fb bent into a U shape, connected by a tapered cylindrical portion 6Fc. The outer diameter of the small-diameter cylindrical portion 6Fa is approximately equal to the inner diameter of the small-diameter hole 9b. The small-diameter cylindrical portion 6Fa, the tapered cylindrical portion 6Fc, and the upper end of the large-diameter U-shaped cylindrical portion 6Fb have the same shapes as in the above-described embodiment. The outflow pipe 6F can be formed by drawing the end of a U-shaped pipe.

[0073] The outflow pipe 6F has a small-diameter inner circumferential surface 6Fe extending within the small-diameter cylindrical portion 6Fa, a tapered inner circumferential surface 6Ff extending within the tapered tubular portion 6Fc, and a large-diameter inner circumferential surface 6Fg extending within the large-diameter U-shaped tubular portion 6Fb. The outflow pipe 6F has a pressure equalizing hole 6Fq in the tapered inner circumferential surface 6Ff, as in the above-described embodiment.

[0074] In this embodiment, after the cup 16 is placed between the header 4 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 press-fitted and fixed into the small-diameter hole 9b of the header 4. As a result, the cup 16 is sandwiched and fixed between the retaining wall 16d and the lower end of the boss 4d.

[0075] According to this embodiment, even if the outflow pipe 6F is U-shaped, the outflow pipe 6F can be attached by moving it linearly without rotating it relative to the header 4, so that in the assembly position shown in Figure 10, the free end of the outflow pipe 6F can be positioned within the cup 16.

[0076] 11 is a longitudinal cross-sectional view of an accumulator 1G according to a third embodiment. The accumulator 1G of this embodiment differs from the accumulator 1F of the second embodiment in the shape of the outflow pipe 6G. Specifically, the bending radius of the bent portion of the large-diameter U-shaped tubular 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 that of the above-described embodiment.

[0077] The small-diameter cylindrical portion 6Ga, the tapered tubular portion 6Gc, and the upper end of the large-diameter U-shaped tubular portion 6Gb have the same shapes as those in the first embodiment. The outflow pipe 6G can be formed by drawing the end of a U-shaped pipe.

[0078] The outflow pipe 6G has a small-diameter inner circumferential surface 6Ge extending within the small-diameter cylindrical portion 6Ga, a tapered inner circumferential surface 6Gf extending within the tapered tubular portion 6Gc, and a large-diameter inner circumferential surface 6Gg extending within the large-diameter U-shaped tubular portion 6Gb. The outflow pipe 6G has a pressure equalizing hole 6Gq in the tapered inner circumferential surface 6Gf, as in the above-described embodiment.

[0079] 12 is a vertical cross-sectional view of an accumulator 101 according to a fourth embodiment, with only the left half of the strainer shown in cross section. The accumulator 101 includes a tank body 102, a double pipe 105 disposed within the tank body 102, a bag 111 containing a desiccant (moisture absorbent) DA, a cup 116, and a strainer 120. The axis of the inner pipe 106 is designated L.

[0080] The tank main body 102 includes a body 103 and a header 104. The body 103 is formed in a cylindrical shape with at least an open upper end, and as an example, is formed in a cylindrical shape with an open upper end and a bottom. The header 104 closes the opening at one end of the body 103. The header 104 is joined to the body 103 by circumferential welding, for example, via a weld 110, and closes the opening of the body 103. The body 103 and the header 104 are both formed of a metal such as an aluminum alloy. In this specification, the header 104 side is referred to as the upper side, and the bottom side of the body 103 is referred to as the lower side.

[0081] For example, a header 104 formed in a substantially disk shape has a refrigerant inlet hole 108 and a refrigerant outlet hole 109 formed therethrough from top to bottom. An inner pipe (also called an outlet pipe) 106 extending to near the inside bottom of the body 3 is connected to the refrigerant outlet hole 109. An outer pipe 107 is fitted around the outside of the inner pipe 106, thereby forming a double pipe 105.

[0082] A cup 116 is provided below the header 104 as a gas-liquid separator that separates the mixed refrigerant (a refrigerant containing both gas and liquid phases) from the refrigerant inlet 108 into a high-density liquid-phase refrigerant and compressor oil (hereinafter referred to as "oil"), and a low-density gas-phase refrigerant. The cup 116 is made of, for example, a resin. The cup 116 has, for example, a cylindrical shape with a top, and is disposed opposite the refrigerant inlet 108 and the refrigerant outlet 109.

[0083] The inner pipe 106 is made of, for example, a metal, such as an aluminum alloy. The inner pipe 106 has an open lower end and, as will be described later, an upper end that is screwed into a refrigerant outlet hole 109 of the header 104. The outer periphery of the inner pipe 106 is fitted into a plurality of pipe ribs 107a that protrude from the inner periphery of the outer pipe 107, thereby stably holding the inner pipe 106 within the outer pipe 107 with a gap therebetween.

[0084] The outer pipe 107 is made of, for example, synthetic resin, and is attached to the inside of the body 3 with its upper end open. A cylindrical strainer 120 is provided at the bottom of the outer pipe 107. The strainer 120 is composed of a cylindrical case 121 made of synthetic resin and having a bottom, and a cylindrical mesh filter 122 that is integrated with the case 121 by insert molding or the like.

[0085] A bag 111 containing a desiccant DA is disposed between the outer pipe 107 and the inner periphery of the body 103 .

[0086] The header 104 is formed by stacking a large cylindrical portion 104a and a thin-walled annular portion 104b having a smaller diameter than the large cylindrical portion 104a, and a step portion 104c is formed between the large cylindrical portion 104a and the thin-walled annular portion 104b, with which the outer periphery of the upper end of the body 103 engages. The upper surface of the large cylindrical portion 104a is formed, for example, as a plane perpendicular to the up-down direction.

[0087] A cylindrical boss 104d is formed on the underside of the header 104, protruding downward from the large cylindrical portion 104a. A refrigerant outlet hole 109 is formed through the boss 104d, vertically penetrating the header 104, and a refrigerant inlet hole 108 is formed adjacent to the boss 104d, vertically penetrating the header 104. The underside of the boss 104d is formed, for example, as a flat surface that is in surface contact with the bottom surface of a cylindrical recess (also referred to as a recess) 116c of a cup 116, which will be described later. The underside of the boss 104d is formed, for example, as a flat surface that is perpendicular to the axis L of the inner pipe 106.

[0088] The refrigerant outlet hole 109 has a large diameter hole 109a formed in an upper part and a small diameter hole 109b formed in a lower part, and a female screw 109c is formed in the small diameter hole 109b. The inner diameter of the large diameter hole 109a is larger than the thread diameter of the female screw 109c.

[0089] The cup 116 of this embodiment can be formed, for example, by press-forming a metal plate. The cup 116 is composed of a side wall 116a and a top wall 116b connected together. A portion of the top wall 116b is plastically deformed so as to shift downward to correspond to the boss 104d, thereby forming a cylindrical recess 116c. The inner diameter of the cylindrical recess 116c is approximately equal to the outer diameter of the boss 104d. For example, one or more ribs may be formed on the upper surface of the top wall 116b.

[0090] A circular hole 116d is formed through the bottom wall of the cylindrical recess 116c. The inner diameter of the circular hole 116d is slightly larger than the inner diameter of the small diameter hole 109b.

[0091] The bottom surface of the cylindrical recess 116c of the cup 116 is formed as a plane that is in surface contact with the lower surface of the boss 104d of the header 104. The bottom surface of the cylindrical recess 116c of the cup 116 is formed as a plane that is perpendicular to the axis of the inner pipe 106, for example, in the range where the lower surface of the boss 104d of the header 104 abuts.

[0092] The inner pipe 106 is made of a metal pipe with a uniform diameter, and the inner pipe 106 is expanded in diameter and compressed in the axial direction by bulging near the upper end thereof, thereby forming a flange 106a that protrudes radially outward from the entire outer periphery. A male thread 106b is also formed on the outer periphery of the upper end of the inner pipe 106. Note that the method for forming the flange 106a is not limited to bulging. As another example, the flange 106a may be formed by beading (threading).

[0093] A pressure equalizing hole 106q is formed below the flange 106a. The pressure equalizing hole 106q penetrates the inside and outside of the inner pipe 106. The pressure equalizing hole 106q is a hole that prevents liquid-phase refrigerant accumulated in the inner pipe 106 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 106q allows not only the liquid-phase refrigerant inside the inner pipe 106 but also the gas-phase refrigerant outside the inner pipe 106 to be sucked up by the compressor, thereby preventing the liquid-phase refrigerant from being sucked up.

[0094] The lower end of the inner pipe 106 may be a flat surface perpendicular to the axis L, as in the embodiment shown in FIG. 4 , or the inner diameter surface may increase as it approaches the lower end, as in the embodiment shown in FIG. 7 , or the outer diameter surface may decrease as it approaches the lower end, as in the embodiment shown in FIG. 8 , or the inner diameter surface may increase and the outer diameter surface may decrease as it approaches the lower end, as in the embodiment shown in FIG. 9 .

[0095] An example of the process of assembling the header 104, cup 116, and inner pipe 106 will now be described. First, the boss 104d of the header 104 is inserted into the cylindrical recess 116c of the cup 116, and the lower end of the boss 104d is brought into contact with the bottom surface of the cylindrical recess 116c. This causes the small diameter hole 109b and the circular hole 116d to be coaxially aligned.

[0096] Next, the inner pipe 106 is brought close to the cup 116 from below. The upper end of the inner pipe 106 is then inserted into the circular hole 116d, and the male thread 106b is screwed into the female thread 109c of the small diameter hole 109b of the header 104.

[0097] As the male thread 106b is threaded into the female thread 109c, the flange 106a approaches the header 104 and abuts against the underside of the cylindrical recess 116c. At this time, the inner pipe 106 is locked with the cup 116 sandwiched between them, and does not move any closer to the header 104. In this state, the cup 116 is sandwiched between the underside of the boss 104d of the header 104 and the flange 106a of the inner pipe 106, and is stably held. This allows the cup 116 to be held in an appropriate position.

[0098] The assembly thus formed is fitted with the outer pipe 107 and strainer 120 in the inner pipe 106, and is then installed inside the body 103 in which the bag 111 is arranged, and then welded to the header 104 to complete the accumulator 101.

[0099] According to this embodiment, the inner pipe 106 is fixed to the header 104 by threading the male thread 106a into the female thread 109c of the small-diameter hole 109b, which eliminates the need for, for example, crimping the inner pipe 106 (no crimped portion is provided inside the refrigerant outflow hole 109). This eliminates the need to insert a crimping tool into the refrigerant outflow hole 109, and also eliminates the need to expand the diameter of the end of the inner pipe 106 by plastic deformation to engage with a step inside the refrigerant outflow hole 109.

[0100] (Operation of Accumulator) The operation of the accumulator 101 configured as above will be described with reference to Fig. 12. In the following description, an example will be described in which the accumulator 101 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.

[0101] When the refrigerant is discharged from the evaporator, it is transported to the accumulator 101 through a connecting pipe (not shown). The refrigerant that reaches the accumulator 101 flows into the body 103 through the refrigerant inlet hole 108, and then collides with the upper surface of the cup 116, where it is separated into high-density liquid-phase refrigerant and oil, and low-density vapor-phase refrigerant (gas refrigerant).

[0102] After gas-liquid separation, the liquid refrigerant and oil are stored in the body 103 due to their own weight. During this process, the liquid refrigerant and oil are further separated, 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 111 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.

[0103] On the other hand, the gas-phase refrigerant after gas-liquid separation flows into the outer pipe 107 from the upper end opening, and flows downward inside the outer pipe 107. Thereafter, the refrigerant turns back at the bottom of the outer pipe 107, passes over the lower end of the inner pipe 106, flows inside, and then rises inside the inner pipe 106 to be guided to the refrigerant outlet hole 109.

[0104] The oil that accumulates in the lower part of the body 103 together with the liquid refrigerant moves toward the bottom of the body 103 due to differences in specific gravity and properties compared to the liquid refrigerant, and is sucked into the gas refrigerant that is drawn into the compressor suction side. The oil passes through the mesh filter 122 of the strainer 120, the oil return hole 107e, and the inner space of the inner pipe 106, in that order, and is returned to the compressor suction side together with the gas refrigerant and circulated. As the oil passes through the mesh filter 122, foreign matter such as sludge is captured and removed from the circulating refrigerant (including oil).

[0105] 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 embodiment, the upper end of the inner pipe 6 is fixed to the small diameter hole 9c by press-fitting, but the upper end of the inner pipe 6 may be expanded relative to the small diameter hole 9c and fixed thereto.

[0106] In the above-described embodiment, the inner pipe 6 and the outflow pipes 6F, 6G are cylindrically shaped, with a circular cross section perpendicular to their respective axes. However, the cross section may have a shape other than a circle. Other examples will be described using the inner pipe 6 as a specific example. The inner pipe 6 has a large-diameter cylindrical portion 6b, a small-diameter cylindrical portion 6a, and a tapered cylindrical portion 6c, each of which has a circular cross section. The large-diameter cylindrical portion 6b, the small-diameter cylindrical portion 6a, and the tapered cylindrical portion 6c of the inner pipe 6 are not limited to having a circular cross section. It is sufficient that the cross-sectional area of ​​the small-diameter cylindrical portion 6a is smaller than that of the large-diameter cylindrical portion, and that the cross-sectional area of ​​the tapered cylindrical portion 6c gradually decreases toward the small-diameter cylindrical portion 6a. For example, it is preferable that the cross-sectional shapes of the small-diameter cylindrical portion 6a, the tapered cylindrical portion 6c, and the large-diameter cylindrical portion 6b are similar to each other. As another example, the large diameter cylindrical portion 6b, the small diameter cylindrical portion 6a, and the tapered tubular portion 6c may be cylindrical with a rectangular cross section. The same applies to the outflow pipes 6F and 6G.

[0107] Furthermore, in the above-described embodiment and modified example, the extending portion is described as the retaining wall 16 and the retaining cylinder 16A formed in a shape corresponding to the outer shape of the inner pipe 6. In another example, the extending portion may be shaped so that at least the intermediate portions 16d3, 16Ad3 abut against the tapered cylindrical portion 6c of the inner pipe 6. In a preferred embodiment, the extending portion is formed in a shape that abuts against at least one of the small cylindrical portion 6e and the large-diameter cylindrical portion 6b in addition to the tapered cylindrical portion 6c. In an even more preferred embodiment, the extending portion has a shape corresponding to the outer shape of the inner pipe 6, like the retaining wall 16 and the retaining cylinder 16A.

[0108] In the second embodiment, the annular holding cylinder 16A is described as an example of an extension portion, but the holding cylinder 16A is not limited to being formed in a continuous annular shape. For example, the holding cylinder 16A may be formed in a C-shape in a plan view. Furthermore, although the holding cylinder 16A has a cylindrical outer shape, the shape is not limited to a cylindrical shape. In another example, the outer shape may be a polygonal prism, such as a square prism.

[0109] In the above-described embodiment, the inner circumferential surfaces of the inner pipe 6 and the outflow pipes 6F, 6G have circular cross sections perpendicular to their respective axes. However, the cross sections of the inner circumferential surfaces may be other than circular. Other examples will be described using the inner pipe 6 as a specific example. The inner pipe 6 has a large-diameter inner circumferential surface 6g, a small-diameter inner circumferential surface 6e, and a tapered inner circumferential surface 6f, each of which has a circular cross section perpendicular to its axis. However, this is not limited to this. The inner circumferential surface of the inner pipe 6 may have any shape as long as the cross-sectional area perpendicular to the axis of the small-diameter inner circumferential surface 6e is smaller than the cross-sectional area perpendicular to the axis of the large-diameter inner circumferential surface 6g, and the cross-sectional area perpendicular to the axis of the tapered inner circumferential surface 6f gradually decreases toward the small-diameter inner circumferential surface 6e. For example, it is preferable that the cross-sectional shapes perpendicular to the axis of the small-diameter inner circumferential surface 6e, the tapered circumferential surface 6f, and the large-diameter inner circumferential surface 6g are similar to each other. In another example, the inner peripheral surface of the inner pipe 6 may have a rectangular cross section perpendicular to the axis. The same applies to the outflow pipes 6F, 6G.

[0110] In the above embodiment, the inner pipe 6 and the outflow pipes 6F, 6G are formed by drawing, but they may be formed by a process other than drawing. In another example, the inner pipe 6 and the outflow pipes 6F, 6G may be formed by expanding the pipes.

[0111] In addition, in the above-described embodiment, an example in which the inner surface of the retaining wall 16d is formed into a curved surface has been described, but in other examples, it may be formed into a flat surface. Even when the inner surface of the intermediate portion 16d3 is formed into a flat surface, the intermediate portion 16d3 abuts against the tapered cylindrical portions of the inner pipe 6 and the outflow pipes 6F, 6G, thereby achieving the same effect as described above. When the inner surface of the tip portion 16d2 is formed into a flat surface, the inner surface of the tip portion 16d2 is formed into a flat surface that abuts against the large-diameter cylindrical portion 6b of the inner pipe 6 and the large-diameter U-shaped cylindrical portion 6Fb of the outflow pipes 6F, 6G, thereby achieving the same effect as described above.

[0112] In the above-described embodiment and modified examples, the cup 16, 116 is an example of a gas-liquid separating member. The gas-liquid separating member faces both the refrigerant inlet hole 8, 108 and the refrigerant outlet hole 9, 109. The gas-liquid separating member has a portion against which the refrigerant flowing in through the refrigerant inlet hole 8, 108 impinges. The gas-liquid separating member preferably faces the entire refrigerant inlet hole 8, 108. The facing direction is the axial direction of the refrigerant inlet hole 8, 108. The gas-liquid separating member preferably has a top wall facing both the entire refrigerant inlet hole 8, 108 and the refrigerant outlet hole 9, 109, and a cylindrical side wall facing the inner circumferential surface of the body 3, 103. Preferably, the gap between the header 4, 104 and the top wall and the gap between the inner circumferential surface of the body 3, 103 and the side wall are substantially the same. Here, "substantially the same" means that in addition to being completely the same, there may be some error. That is, when the refrigerant flowing in through the refrigerant inlet holes 8, 108 hits the top wall and flows downstream, it flows through the gap between the top wall and the header 4, 104 and the gap between the inner circumferential surface of the body 3, 103 and the side wall. If 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. Thus, the error is 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 member with a constant thickness. Furthermore, another example of a gas-liquid separating member has a structure without side walls.

[0113] This specification includes the disclosure of the following inventions. a refrigerant inlet port and a refrigerant outlet port, the refrigerant outlet port being formed in a portion opposite the refrigerant outlet port, the refrigerant outlet pipe having a small cylindrical portion inserted into and fixed to the refrigerant outlet port, a large cylindrical portion disposed within the body and having a cross-sectional area larger than that of the small cylindrical portion, and a tapered cylindrical portion connecting the small cylindrical portion and the large cylindrical portion; and an inner circumferential surface of the outlet pipe having, in the refrigerant flow direction, a large inner circumferential surface, an intermediate inner circumferential surface connected to the large inner circumferential surface, and a small inner circumferential surface connected to the intermediate inner circumferential surface and having a cross-sectional area smaller than that of the large inner circumferential surface, the intermediate inner circumferential surface having a cross-sectional area that gradually decreases toward the small inner circumferential surface. the gas-liquid separating member has the communicating portion, a main body facing the header, and an extension portion extending from the main body to the tapered cylindrical portion, and is sandwiched between the header and the outflow pipe with the extension portion abutting the tapered cylindrical portion.

[0114] (Second Aspect) The accumulator according to the first aspect, wherein the outflow pipe is formed in a cylindrical shape having a circular cross section.

[0115] (Third Aspect) The accumulator according to the first or second aspect, wherein the extension portion abuts against an outer peripheral surface of the large cylindrical portion.

[0116] (Fourth Aspect) The accumulator according to any one of the first to third aspects, wherein a plurality of the extension portions are provided in the circumferential direction of the outflow pipe.

[0117] (Fifth Aspect) The accumulator according to any one of the first to fourth aspects, wherein the extension portion is formed in a cylindrical shape that abuts against the tapered cylindrical portion over the entire circumference.

[0118] (Sixth Aspect) The accumulator of the fifth aspect, characterized in that it has an outer pipe that is housed within the body portion and formed in a cylindrical shape with the outflow pipe disposed inside, and that has an open end on the gas-liquid separating member side, and the extension portion has a guide portion that guides the refrigerant outside the outer pipe to the opening of the outer pipe on the gas-liquid separating member side, and the guide portion is formed by the outer peripheral surface of the extension portion and has a shape that expands in diameter as it approaches the gas-liquid separating member side.

[0119] (Seventh Aspect) The accumulator according to the second aspect, wherein the outflow pipe is formed by drawing or expanding a pipe.

[0120] (Eighth Aspect) The accumulator according to any one of the first to seventh aspects, wherein the outflow pipe is press-fitted into the refrigerant outflow hole.

[0121] (Ninth Aspect) The accumulator according to any one of the first to eighth aspects, wherein a male thread formed on the outflow pipe and a female thread formed on the refrigerant outflow hole are threadedly engaged with each other.

[0122] (Tenth aspect) A method for manufacturing an accumulator having: a header with a refrigerant outflow hole; an outflow pipe connected to the refrigerant outflow hole; and a gas-liquid separating member arranged opposite the header and having a communication portion through which a portion of the outflow pipe is arranged, the method comprising: forming the outflow pipe having a small cylindrical portion, a large cylindrical portion having a cross-sectional area larger than that of the small cylindrical portion, and a tapered cylindrical portion connecting the small cylindrical portion and the large cylindrical portion by applying a drawing or expansion process to a pipe; forming an extension portion extending in a direction away from the main body portion of the gas-liquid separating member which is arranged opposite the header; with the small cylindrical portion of the outflow pipe arranged in the communication portion, bringing the extension portion and the tapered cylindrical portion close to each other so that the extension portion abuts against the tapered cylindrical portion; fixing the small cylindrical portion to the refrigerant outflow hole of the header and bringing the extension portion abutting against the tapered cylindrical portion, the method for manufacturing an accumulator

[0123] (Eleventh 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 one end of the body portion; and an outflow pipe housed within the body portion and connected to the refrigerant outlet hole, wherein the outflow pipe has a male thread formed on an end thereof, the refrigerant outlet hole has a female thread, and the outflow pipe is attached to the header by screwing the male thread into the female thread.

[0124] (12th Aspect) The accumulator of the 11th aspect, characterized in that the accumulator has a gas-liquid separating member housed within the body portion, the gas-liquid separating member having a communication portion formed in a portion facing the refrigerant outflow hole that communicates the header side with the opposite side, the outflow pipe having a flange portion protruding radially outward from the outer peripheral surface near the male thread, a portion of the outflow pipe being disposed in the communication portion, and the gas-liquid separating member being held between the flange portion and the header when the outflow pipe is attached to the header.

[0125] (13th Aspect) The accumulator of the 11th or 12th aspect, characterized in that the header has a boss portion around the refrigerant outflow hole, the gas-liquid separation member has a recess that fits into the boss portion, and when the outflow pipe is attached to the header, a bottom wall of the recess is held between the flange portion and the boss portion.

[0126] (14th Aspect) The accumulator according to any one of the 11th to 13th aspects, wherein the gas-liquid separating member is formed by press-forming a metal plate material.

[0127] DESCRIPTION OF SYMBOLS 1, 101 Accumulator 2, 102 Tank body 3, 103 Body 4, 104 Header 5, 105 Double pipe 6, 6B, 6C, 6D, 106 Inner pipe (outlet pipe) 6F, 6G U-shaped outlet pipe 6a, 6Fa, 6Ga Small diameter cylindrical portion 6b Large diameter cylindrical portion 6c, 6Fc, 6Gc Tapered cylindrical portion 106a Flange portion 7, 107 Outer pipe 8, 108 Refrigerant inlet hole 9, 109 Refrigerant outlet hole 11, 111 Bag 20, 120 Strainer 21, 121 Case 22, 122 Mesh filter

Claims

1. a body having an opening at at least one end; a header provided with a refrigerant inlet hole and a refrigerant outlet hole, closing one end of the body; a gas-liquid separation member accommodated in the body, having a communication portion formed at a portion facing the refrigerant outlet hole for communicating the header side and the opposite side thereof; an outflow pipe accommodated in the body with a part thereof disposed in the communication portion and connected to the refrigerant outlet hole; the outflow pipe; a small cylindrical portion inserted into and fixed to the refrigerant outlet hole; a large cylindrical portion disposed in the body and having a larger cross-sectional area than the small cylindrical portion; a tapered cylindrical portion connecting the small cylindrical portion and the large cylindrical portion; the inner peripheral surface of the outflow pipe has, along the flow direction of the refrigerant, a large inner peripheral surface, an intermediate inner peripheral surface connected to the large inner peripheral surface, and a small inner peripheral surface connected to the intermediate inner peripheral surface and having a cross-sectional area smaller than that of the large inner peripheral surface, and the intermediate inner peripheral surface has a shape in which the cross-sectional area gradually decreases toward the small inner peripheral surface side; the gas-liquid separation member has the communication portion, a main body facing the header, and an extending portion extending from the main body to the tapered cylindrical portion, and is sandwiched between the header and the outflow pipe in a state where the extending portion abuts against the tapered cylindrical portion; an accumulator characterized by the above.

2. the outflow pipe is formed in a cylindrical shape with a circular cross-sectional shape; the accumulator according to claim 1, characterized by the above.

3. the extending portion abuts against the outer peripheral surface of the large cylindrical portion; the accumulator according to claim 1, characterized by the above.

4. a plurality of the extending portions are provided in the circumferential direction of the outflow pipe; the accumulator according to claim 1, characterized by the above.

5. the extending portion is formed in a cylindrical shape that abuts against the tapered cylindrical portion over the entire circumference; the accumulator according to claim 1, characterized by the above.

6. an outer pipe accommodated in the body, formed in a cylindrical shape with the outflow pipe disposed inside, and having an opening at an end on the gas-liquid separation member side; the extending portion has a guide portion for guiding the refrigerant outside the outer pipe to the opening on the gas-liquid separation member side of the outer pipe, the guide portion is constituted by the outer peripheral surface of the extending portion, and has a shape in which the diameter expands toward the gas-liquid separation member side; the accumulator according to claim 5, characterized by the above.

7. the outflow pipe is formed by performing a pipe throttling process or a pipe expanding process; The accumulator according to claim 2, characterized in that...

8. The outflow pipe is press-fitted into the refrigerant outflow hole. The accumulator according to claim 1, characterized in that...

9. The male thread formed on the outflow pipe and the female thread formed on the refrigerant outflow hole are screwed together. The accumulator according to claim 1, characterized in that...

10. The extension part abuts against the tapered cylinder part from the end on the small cylinder part side to the end on the large cylinder part side of the tapered cylinder part. The accumulator according to claim 1, characterized in that...

11. A header having a refrigerant outflow hole, An outflow pipe connected to the refrigerant outflow hole, A gas-liquid separation member disposed opposite to the header and having a communication portion for disposing a part of the outflow pipe, A method for manufacturing an accumulator having the above components, comprising: By performing a necking process or an expanding process on a pipe, an outflow pipe having a small cylinder part, a large cylinder part having a larger cross-sectional area than the small cylinder part, and a tapered cylinder part connecting the small cylinder part and the large cylinder part is formed. An extension part extending in a direction away from the main body part is formed on the main body part of the gas-liquid separation member that becomes the part disposed opposite to the header. With the small cylinder part of the outflow pipe disposed in the communication portion, the extension part and the tapered cylinder part are brought closer to each other so that the extension part abuts against the tapered cylinder part. The gas-liquid separation member is sandwiched between the header and the outflow pipe by fixing the small cylinder part to the refrigerant outflow hole of the header and bringing the extension part into contact with the tapered cylinder part. A method for manufacturing an accumulator, characterized by the above.

12. The extension part abuts against the tapered cylinder part from the end on the small cylinder part side to the end on the large cylinder part side of the tapered cylinder part. The method for manufacturing an accumulator according to claim 11, characterized in that...