JP2006218517A - Metallic draw pipe, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seamless integrated metallic draw pipe, and its manufacturing method. <P>SOLUTION: In the metallic draw pipe, a contracted pipe portion, an expanded pipe portion and a non-worked original pipe portion are continuously integrated in a seamless manner via a tapered portion through a plurality of drawing sets, and the metallic draw pipe comprises, from one end to the other, the contracted pipe portion, the tapered portion, the original pipe portion, the tapered portion, the contracted pipe portion, the tapered portion, and the expanded pipe portion. In the metallic draw pipe manufacturing method, a die having at least one groove in an inner circumferential surface of a through-hole is turned and pressed into an original pipe under pressure to perform contraction, and a boss having at least one flat portion in an outer circumferential surface is turned and pressed into the original pipe under pressure to perform the expansion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a metal throttle tube and a method of manufacturing the same, and more specifically, a die having a groove on the inner peripheral surface, or a boss having an R portion and a flat portion having a radius larger than the inner diameter to be expanded on the outer peripheral surface. The present invention relates to a copper tube or a brass tube which has been contracted or expanded by being pushed into the original tube while rotating, and a method for producing the same.

Recent air conditioners and refrigerators tend to use high-pressure carbon dioxide due to Freon regulations. For example, a heat pump water heater called Ecocute, which uses carbon dioxide (CO ₂ ) as a refrigerant, collects atmospheric heat with a heat exchanger for air, transfers it to the refrigerant, compresses it with a compressor, further increases the temperature, This is a system in which the heat of the refrigerant is transferred to water by a heat exchanger for water heating, and the refrigerant that has lost heat is sent again to the heat exchanger for air. Even if carbon dioxide is compressed, it does not become a liquid and remains a gas, so that efficient heat exchange is possible. Thereby, water can be boiled to about 90 degreeC. The pressure at the compressor of such a water heater is as high as 8 MPa to 15 MPa, for example. In addition, even if it compares with the pressure of tap water 0.7MPa, it is a large pressure.

  In heat pump water heaters and water heaters that are also expected to prevent global warming, in order to handle high-pressure gas instead of liquid, there is a need for seamlessly small-diameter piping parts. Moreover, cost reduction is essential for the spread of equipment. As part of this, the present invention aims at seamless integration of piping parts that handle high-pressure refrigerant, such as a heat pump type water heater, water heater, or cooler, and a reduction in processing costs.

  High-pressure copper pipes for refrigerants used in conventional refrigerators and air-conditioning equipment are copper pipes or aluminum pipes with relatively large diameters, and joining pipes of different thickness is done by narrowing one end of one pipe. A joining process was required. In addition, in order to improve the thermal efficiency of the heat exchanger, the outer diameter of the tube on the heat exchanger side tends to become narrow, for example, from 9.5 mm to 7.0 mm, and further to 6.3 mm. . This is because, generally, if the outer diameter of the tube is reduced, it can withstand high pressure even if the wall thickness is reduced. Even at the same high pressure, if the outer diameter of the tube is large, the wall thickness must be increased. Therefore, when connecting from the compressor side pipe to the heat exchanger side pipe, it is necessary to reduce the outer diameter of the pipe for connection. The present technology allows this to be done without coupling.

  FIG. 6 shows a joint portion of a conventional copper tube component. The end portion of the copper tube 40 is contracted to have a small diameter, and a small diameter copper tube 60 is inserted into the end portion and brazed. Therefore, it has been necessary to strictly check whether there is a leak or a slow leak due to a pinhole in the joint by a pressure test or the like. Therefore, it is desirable to make the parts as seamless as possible and to reduce the number of joints of the pipes by the joints.

  FIG. 7 is a process diagram in which a tube having an outer diameter of 12.7 mm (inner diameter is 11.1 mm) is reduced to an outer diameter of 5.5 mm (inner diameter is 3.1 mm) in a conventional manner. . As shown in FIG. 9, the conventional method is a method in which a die 5 for contraction is pressed and deformed by applying pressure to one end of the original tube 1. In this case, as shown in FIG. 7, the outer diameter of the tube is 12.7 mm → 9.7 mm → 8.2 mm → 6.3 mm → 5.5 mm, and the inner diameter of the tube is 3.1 mm. One process is required. In other words, a step is provided in which the outer diameter is reduced step by step while the die is changed, the diameter is reduced to 5.5 mm, and the inner diameter that is finally narrowed is increased to 3.1 mm. Note that if a large force is applied to complete the process in one step, the tube will buckle.

FIG. 8 is a process diagram for expanding a tube having an outer diameter of 12.7 mm (inner diameter is 11.1 mm) to an inner diameter of 20 mm in a conventional manner. As shown in FIG. 10, the conventional method is a method in which a boss 11 for pipe expansion is pressed and deformed by applying pressure to the original pipe 1. In this case, as shown in FIG. 8, the inner diameter is 11.1 mm → 12.7 mm → 15.0 mm → 17.0 mm → annealing → 20.0 mm. This is because if the tube is not annealed, the tube may not be soft and may break. As described above, since the contraction and expansion for connecting the pipes require man-hours, it is desired that the tube can be processed with fewer steps even when the contraction or expansion is necessary.
JP 2001-133169 A

  An object of the present invention is to provide a method of manufacturing a metal throttle tube that can integrate a metal throttle tube in a heat exchanger without a seam and can reduce and expand the tube with a small number of steps. The smaller number of steps means that a conventional process that requires five processes for contraction or expansion can be performed in one process.

  The metal drawn pipe according to the present invention is a metal pipe made of a copper pipe or a brass pipe, and a plurality of drawn parts are continuously connected without a seam through a tapered part through a tapered part, an expanded part and an unprocessed original pipe part. It is integrally formed, and is composed of a contraction tube portion, a taper portion, an original tube portion, a taper portion, a contraction tube portion, a taper portion, and a tube expansion portion sequentially from one end to the other end portion.

  The metal throttle tube manufacturing method according to the present invention is a molding method for forming a contraction tube portion or a tube expansion portion in a metal tube via a taper portion, and one or more are formed on the inner peripheral surface of a through hole provided in the center. A dice for contraction tube in which a groove is formed, and a boss for expansion of tube having an R portion and a flat portion formed on the outer peripheral surface, and when performing contraction, match the inner diameter of the tube obtained by molding The mandrel is inserted into the through hole or the original tube of the die and attached, and the metal original tube is fixed to an installation base, the rotating die is lowered, and the metal original tube is applied with pressure. When the metal original tube is contracted through the throttle hole and expanded, the metal original tube is fixed to an installation base, and the rotating boss is lowered. Press against the upper end of the metal pipe while applying pressure to the metal pipe. Push the nest, characterized in that the tube expansion.

  The die has an opening at one end larger than the outer diameter of the original tube and an opening at the other end having an inner diameter equal to the outer diameter of the tube after the diameter reduction, and the funnel-shaped taper portion connecting the openings. And a through hole made of a straight portion having a constant inner diameter is formed, and the groove has a predetermined width, and at least one of the grooves extends along the inner peripheral surface of the tapered portion and / or the straight portion along the axial direction. It is preferable to be formed.

  The boss has a cylindrical projection having an outer diameter smaller than the inner diameter of the original tube at the tip, a conical portion following the projection, and a cylindrical main body equal to the inner diameter of the tube after expansion, It is preferable that the R portion has a radius larger than an inner diameter to be expanded, and one or more flat portions are formed with a predetermined width.

  The metal throttle tube according to the present invention is subjected to tube expansion processing or tube contraction processing by the manufacturing method according to claim 2.

  According to the first aspect of the present invention, since the metal throttle tube according to the present invention is an integrally formed tube without a seam, it is possible to prevent a pinhole from being generated between the inlet and the outlet of the component and the refrigerant from leaking. In addition, a withstand voltage test as a part becomes unnecessary. Furthermore, since there is no seam, the inner circumference including the tapered portion is gentle, and there is no resistance to flow.

  According to the second aspect of the present invention, the metal throttle tube manufacturing method according to the present invention includes a die having a groove on the inner peripheral surface or a boss provided with an R portion and a flat portion on the outer peripheral surface when contracting or expanding the tube. Since this die or boss is rotated and pressed against the original pipe, the pressing force can be reduced to 1/10 of the conventional pressure. Therefore, it is not necessary to make the equipment large.

  Further, there is no need to process in stages while changing dies or bosses, and the process of contraction and expansion can be performed in one process, which conventionally required five processes. When the piping component performs two contraction pipes and one pipe expansion, the 15 steps are three steps. That is, the manufacturing cost can be reduced by reducing the number of processes.

  Further, since the dice having grooves and the bosses having the R part and the flat part are rotated and used, the wall thickness of the contracted tube part or the expanded tube part can be further reduced. This is because the conventional pressure method is processed only by a vertical force from the top to the bottom, but the present processing method including rotation can also add a horizontal direction. Furthermore, since the mandrel is attached to the die or the original tube at the time of contraction, the outer diameter of the mandrel can be formed to a desired inner diameter.

  According to claim 3, the groove of the die provided along the axial direction has irregularities on the inner peripheral surface of the through hole, and acts to concentrate and compress the original tube. Efficiency can be improved significantly. Further, since the processing by the conventional pressure method does not have a mandrel and the mandrel is inserted, the processing becomes impossible, so that the wall thickness after the contraction always increases. On the other hand, if the die is rotated and used, the mandrel can be processed with or without rotation, and the mandrel can be processed to a thinner wall thickness.

  According to the fourth aspect, the R portion and the flat portion having a radius larger than the inner diameter to be expanded are provided with irregularities on the outer peripheral surface of the boss, and act to concentrate and widen the inner periphery of the original tube. , Processing efficiency can be significantly improved. Moreover, it can be made thinner.

  According to the fifth aspect of the present invention, the metal throttle tube subjected to the contraction or expansion processing by the manufacturing method according to the second aspect is suitable for mass production since the manufacturing process is short.

  The metal throttle tube and its manufacturing method will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view of a metal throttle tube according to the present invention. The metal drawn tube 100 according to the present invention is made of a copper tube, and a plurality of drawing processes are performed so that the reduced tube portion, the expanded tube portion, and the unprocessed original tube portion are continuously and integrally formed through the taper portion without any joint. In order to the other end, the tube is composed of a contracted tube portion 20, a tapered portion 21, an original tube portion 22, a tapered portion 23, a contracted tube portion 24, a tapered portion 25, and a tube expanded portion 26. In the present embodiment, the total length is 175 mm, the first contracted tube portion 20 is 55 mm including the tapered portion 21, the original tube portion 22 following this is 20 mm, and the filter 17 is built therein. The second contracted tube portion 24 is 90 mm including the tapered portion 23. The tube expansion part 26 following this is 10 mm including the taper part 25. The filter 17 is inserted into the original pipe portion in advance, and then the front and rear thereof are contracted to integrally form the contracted tube and the expanded portion.

  The first contracted tube portion 20 has an outer diameter of 9.5 mm, an inner diameter of 6.1 mm, and a wall thickness of 1.7 mm. The original pipe part 22 has an outer diameter of 12.7 mm, an inner diameter of 8.1 mm, and a wall thickness of 2.3 mm. The second contracted tube portion 24 has an outer diameter of 6.3 mm, an inner diameter of 3.9 mm, and a wall thickness of 1.2 mm. The expanded pipe portion 26 has an outer diameter of 8 mm, an inner diameter of 6 mm, and a wall thickness of 1 mm. In addition, such a dimension is not restricted to this in one Example.

  FIG. 2 is a block diagram showing a reduced tube processing method among the methods for manufacturing a metal drawn tube according to the present invention. The original tube 1 is fixed to the mounting table 16 by applying pressure from the left and right. The die 5 is attached to a fixing jig 4 provided on the spindle 3. Next, the die 5 is lowered while rotating. Further, pressure is applied in the direction indicated by the arrow to push the die 5 into the original tube 1. The mandrel 2 having an outer diameter equal to the inner diameter of the tube after the diameter reduction is disposed in the through hole 18 of the die 5. The mandrel 2 may be mounted in the original tube 1.

  FIG. 3 shows the structure of the dice. (A) is a top view of the dice | dies 5, (b) is AA sectional drawing of (a). The die 5 is annular and has a through hole 18 in the center, and is made of cemented carbide. A through-hole 18 comprising a funnel-shaped tapered portion 28 and a straight portion 29 having a constant inner diameter is formed by connecting the opening 7 and the opening 8. The inner diameter of the through hole of the opening 7 is larger than the outer diameter of the original tube 1, and the inner diameter of the through hole of the opening 8 is made equal to the outer diameter of the tube after the reduction. The inner peripheral portion 6 has a mirror finish and is formed in a funnel shape. In addition, two grooves 9 having a predetermined width are provided on the inner peripheral surface of the through hole 18 along the shaft 27 of the die 5 and having an interval of 180 degrees around the shaft 27. One groove 9 may be provided. Moreover, you may provide 4-6. The groove 9 acts so that the outer peripheral portion of the original tube 1 can be grasped and intensively compressed during the contraction processing.

  Cemented carbide is a tungsten carbide ceramic powder baked and hardened using cobalt or nickel as a binder. Melting point is about 3000 degrees and it is strong at high temperature. Moreover, hardness is as hard as 80-94 by HRA, and intensity | strength is as large as 2 Gpa or more. Young's modulus is about three times that of iron. In other words, it is resistant to heat and does not wear, so it can be processed at room temperature. No cooling equipment is required. If the copper tube can be discolored and oxidized by heat, the die may be made of steel.

  In the tube shrinking process, the die 5 is attached to the fixing jig 10 with the end 7 larger than the outer diameter of the original tube 1 facing downward and is lowered while rotating, and then the die 5 is brought into contact with the original tube 1 and simultaneously downward. To reduce the diameter. When the length of the reduced diameter portion reaches a predetermined length, the processing is terminated, and the die 5 and the spindle 3 are pulled up and pulled out from the processed copper tube portion. After loosening the mounting table 16 that fixes the original pipe 1, the processed copper pipe is removed.

  In the present embodiment, the die 5 when forming the first contracted tube portion 20 of the metal throttle tube 100 has an inner diameter of the through hole of the end portion 7 of 12.7 mm and an inner diameter of the through hole of the end portion 8 of 9. .5 mm was used. The outer diameter of the mandrel 2 is 6.1 mm. The die 5 is fixed to the fixing jig 4 with the end 7 facing downward. The rotational speed of the die 5 was about 1500 rpm. The tube is contracted by applying a pressure of 500 kg while rotating. Similarly, the die 5 used for forming the second contracted tube portion 24 was one having an inner diameter of the through hole of the end portion 7 of 12.7 mm and an inner diameter of the through hole of the end portion 8 of 6.3 mm. At that time, the outer diameter of the mandrel 2 was 3.9 mm. Under such processing conditions, the material of the raw tube 1 is preferably copper or brass, and aluminum is not preferable because peeling occurs. The number of rotations varies depending on the shape of the metal tube and its application, and is not limited to 1500 rpm.

  FIG. 4 is a block diagram showing a tube expansion method among the methods for manufacturing a metal throttle tube according to the present invention. The original tube 1 is fixed to the mounting table 16 by applying pressure from the left and right. The boss 11 is attached to a fixing jig 10 provided on the spindle 3. Next, the boss 11 is lowered while rotating. Further, pressure is applied in the direction indicated by the arrow to push the boss 11 into the original tube 1.

  FIG. 5 shows the structure of the boss. (A) is a front view of the boss | hub 11, (b) is a bottom view. The boss 11 is composed of a protruding portion 12, a conical portion 13 following the protruding portion 12, and a main body portion 14, and is made of cemented carbide. The outer diameter of the boss 11 is formed equal to the inner diameter of the pipe after the expansion. The outer diameter of the protrusion 12 is equal to or smaller than the inner diameter of the original tube 1. The surface of the boss 11 is mirror finished. Further, on the outer peripheral surface of the boss, four flat portions 15 are provided along the shaft 30 in both the conical portion 13 and the main body portion 14. The R portion 31 following the flat portion 15 has a radius larger than the inner diameter to be expanded. One flat portion 15 may be provided. When the flat portion 15 is provided, as shown in FIG. 5 (b), the outer peripheral surface has a shape close to a square when viewed from the axial direction. Acts to spread intensively.

  In the pipe expansion process, the boss 11 is fixed to the fixing jig 10 and lowered while rotating, then the boss 11 is brought into contact with the original pipe 1, and pressure is further applied downward to reduce the diameter. The process ends when the length of the expanded portion reaches a predetermined length, and the boss 11 and the spindle 3 are pulled up. After loosening the mounting table 16 that fixes the original pipe 1, the processed copper pipe is removed.

  In this example, in the metal throttle tube 100, the second contracted tube portion 24 having an outer diameter of 6.3 mm and an inner diameter of 3.9 mm was expanded. The expanded pipe portion 26 has an outer diameter of 8 mm and an inner diameter of 6 mm. That is, the inner diameter of the tube was expanded from 3.9 mm to 6 mm. The outer diameter of the main body 14 of the boss 11 used for processing was therefore 6 mm. The tube can be expanded by a single process without an annealing process. The rotational speed of the boss 11 was about 1500 rpm. Tube expansion is performed by applying a pressure of 500 kg while rotating.

  The present invention provides a seamless metal throttle pipe, and is widely applicable not only to a heat exchanger but also to a high-pressure piping section.

It is sectional drawing of the metal throttle tube by this invention. It is a block diagram which shows the reduced tube processing method by this invention. FIG. 3 is a structural diagram of a die for reducing tube processing according to the present invention. (A) is a top view, (b) is AA sectional drawing of (a). It is a block diagram which shows the pipe expansion processing method by this invention. It is a structural diagram of the boss for pipe expansion processing by the present invention. (A) is a front view, (b) is a bottom view. It is a figure which shows the junction part of the conventional copper pipe components. It is process drawing of the conventional contraction tube. It is process drawing of the conventional pipe expansion. It is a figure which shows the processing method of the reduced tube using the conventional die. It is a figure which shows the processing method of the pipe expansion using the conventional boss | hub.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Original pipe 2 Mandrel 3 Spindle 4 Fixing jig 5 Dies 6 Inner peripheral part 7, 8 Opening part 9 Groove 10 Fixing jig 11 Boss 12 Protrusion part 13 Conical part 14 Body part 15 Flat part 16 Mounting base 17 Metal filter 18 Through Hole 19 Metal throttle tube shaft 20 First contraction tube portion 21 Taper portion 22 Original tube portion 23 Taper portion 24 Second contraction tube portion 25 Taper portion 26 Tube expansion portion 27 Die shaft 28 Tapered portion of die through hole 29 Straight part of die through hole 30 Boss shaft 31 R part 40, 60 Copper pipe 100 Metal throttle pipe

Claims (5)

  A metal tube composed of a copper tube or a brass tube, and a contracted tube portion, an expanded tube portion, and an unprocessed raw tube portion are continuously and integrally formed through a taper portion by a plurality of drawing processes, from one end to the other end. A metal throttle tube comprising a contraction tube portion, a taper portion, an original tube portion, a taper portion, a contraction tube portion, a taper portion, and a tube expansion portion sequentially. A forming method for forming a contracted tube portion or a expanded tube portion through a taper portion on a metal tube,
A die for contraction tube in which a groove is formed on the inner peripheral surface of a through hole provided in the center, and a boss for tube expansion in which an R portion and a flat portion are formed on the outer peripheral surface;
When contracting the tube, insert a mandrel that matches the inner diameter of the tube obtained by molding into the through hole of the die or the original tube, and fix the metal original tube to the mounting base. The rotating die is lowered, pressed against the upper end of the original metal pipe while applying pressure, and the original metal pipe is contracted through the through hole,
When expanding the pipe, the metal pipe is fixed to an installation base, the rotating boss is lowered, pressed against the upper end of the metal pipe while applying pressure, and the boss is pressed against the metal pipe. A method of manufacturing a metal throttle tube, wherein the tube is expanded by pushing in.   The die has an opening at one end larger than the outer diameter of the original tube and an opening at the other end having an inner diameter equal to the outer diameter of the tube after the diameter reduction, and the funnel-shaped taper portion connecting the openings. And a through hole made of a straight portion having a constant inner diameter is formed, and the groove has a predetermined width, and at least one of the grooves extends along the inner peripheral surface of the tapered portion and / or the straight portion along the axial direction. 3. The method for producing a metal throttle tube according to claim 2, wherein the metal throttle tube is formed.   The boss has a cylindrical projection having an outer diameter smaller than the inner diameter of the original tube at the tip, a conical portion following the projection, and a cylindrical main body equal to the inner diameter of the tube after expansion, 3. The method of manufacturing a metal throttle tube according to claim 2, wherein the R portion has a radius larger than an inner diameter to be expanded, and at least one flat portion is formed with a predetermined width.   A metal drawn pipe, which has been subjected to pipe expansion or contraction by the manufacturing method according to claim 2.

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