Chuck mechanism, tube expansion method, and heat exchanger manufacturing method

Abstract

This chuck mechanism (500) comprises: chuck claws (160) that are disposed separated in the circumferential direction on the outside of a hairpin tube (3) of a heat exchanger, and that grip the hairpin tube (3); a chuck claw sliding component (170) that is formed in a cylindrical shape and slidably holds the chuck claws (160) inside and outside in the radial direction; and a sleeve (110) that is formed in a cylindrical shape and slides the chuck claws (160) towards a refrigerant tube relative to the chuck claw sliding component (170).

Description

Chuck mechanism and tube expansion method

[0001] The present disclosure relates to a chuck mechanism and a tube expansion method.

[0002] One method for manufacturing a heat exchanger involves inserting multiple hairpin tubes through heat dissipation fins stacked at a predetermined interval, expanding the hairpin tubes, and then securing the hairpin tubes to the heat dissipation fins. This method has the problem that if the tube opening is not secured during expansion, the overall length of the expanded tube will be reduced. To address this issue, Patent Documents 1 and 2 propose a method in which the tube is gripped near the opening and secured in the direction of insertion of the expansion mandrel.

[0003] Patent No. 6124044 Patent No. 6191889

[0004] The methods described in Patent Documents 1 and 2 use a cylindrical chuck mechanism to grip the vicinity of the tube opening. The tube gripping portion of the chuck mechanism has slits spaced at regular intervals along the axial direction. The slit ends serve as fulcrums, causing the tip diameter of the chuck tip to shrink and grip the tube. However, with this method, when the tube diameter varies, for example, when gripping a tube with a smaller diameter, the tip diameter of the chuck mechanism shrinks more than usual. As a result, the chuck tip and the tube make point contact in the circumferential direction of the tube, and the stress at the contact point is greater than usual. This results in problems such as tube deformation, which can lead to cracking at the deformed portion of the tube. Similar problems also occur when gripping a tube with a larger diameter.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a chuck mechanism and a tube expansion method that can reduce tube deformation during tube expansion of a heat exchanger and expand the heat exchanger with high quality.

[0006] In order to achieve the above object, the chuck mechanism of the present disclosure includes a plurality of chuck claws arranged circumferentially spaced apart on the outside of a refrigerant pipe of a heat exchanger and gripping the refrigerant pipe, a tubular chuck claw sliding component that holds the chuck claws so that they can slide radially inward and outward, and a tubular sleeve that slides the chuck claws relative to the chuck claw sliding component toward the refrigerant pipe.

[0007] In the present disclosure, when the tube is first expanded, the chuck jaws come into line contact or surface contact with the tube, allowing the chuck jaws to grip the tube, thereby reducing deformation of the tube during expansion of the heat exchanger and enabling the heat exchanger to be expanded with high quality.

[0008] (a) Schematic diagram of fins and (b) schematic diagram of tubes of a heat exchanger according to embodiment 1 of the present disclosure. Schematic diagram of a manufacturing process for a heat exchanger according to embodiment 1 of the present disclosure. (a) to (d) schematic diagram of a tube expansion process for a heat exchanger according to embodiment 1 of the present disclosure. (a) to (c) structural diagram of a chuck mechanism according to embodiment 1 of the present disclosure. Perspective view of a chuck jaw sliding part according to embodiment 1 of the present disclosure. (a) to (d) structural diagram of a chuck jaw according to embodiment 1 of the present disclosure. Flowchart showing a primary tube expansion process for a heat exchanger according to embodiment 1 of the present disclosure. (a) to (c) structural diagram of a chuck mechanism according to embodiment 1 of the present disclosure. (a) to (c) Schematic diagrams of the primary tube expansion process of a heat exchanger. (a) to (c) Schematic diagrams showing the operation of a chuck mechanism in the primary tube expansion process of a heat exchanger according to embodiment 1 of the present disclosure. (a) to (c) Structural diagrams of a chuck mechanism according to embodiment 2 of the present disclosure. (a) to (d) Schematic diagrams of the process of inserting a hairpin tube into a chuck jaw sliding part of the chuck mechanism according to embodiment 2 of the present disclosure. (a) and (b) Structural diagrams of a chuck mechanism according to embodiment 3 of the present disclosure. (a) and (b) Structural diagrams of a chuck mechanism according to embodiment 4 of the present disclosure. (a) to (c) Structural diagrams of a chuck mechanism according to embodiment 5 of the present disclosure.

[0009] Hereinafter, specific embodiments of the chuck mechanism and the tube expanding method according to the present disclosure will be described with reference to the accompanying drawings. Note that the present disclosure is not limited to the following embodiments.

[0010] First Embodiment First, with reference to FIGS. 1( a ) and 1 ( b ), fins 1 and hairpin tubes 3 serving as refrigerant tubes of a heat exchanger according to a first embodiment of the present disclosure will be described.

[0011] The fin 1 shown in Fig. 1(a) has a plurality of burring holes 2 formed in a thin plate of an aluminum material containing pure aluminum and an aluminum alloy. The hairpin tube 3 shown in Fig. 1(b) is a circular tube made of pure copper, a copper material containing a copper alloy, or an aluminum material. The hairpin tube 3 has tube openings 31 at both ends and a bent hairpin portion 32.

[0012] Next, a manufacturing process for the heat exchanger according to the first embodiment of the present disclosure will be described with reference to FIG.

[0013] First, in Step 1, fins 1 are formed by press working, and multiple formed fins 1 are stacked to form stacked fins 4. Additionally, multiple hairpin tubes 3 are manufactured in a process separate from the process for stacked fins 4. Tube openings 31 at both ends of the hairpin tube 3 face upward.

[0014] Next, in Step 2, the stacked fin 4 and the hairpin tube 3 are assembled together. As a result, the tube opening 31 of the hairpin tube 3 protrudes from the upper end of the stacked fin 4, and the hairpin portion 32 protrudes from the lower end of the stacked fin 4.

[0015] Next, in Step 3, the hairpin tubes 3 are expanded at the tube openings 31 of the hairpin tubes 3 attached to the stacked fins 4 using a tube expansion component to form the piping attachment shape 5. Thereafter, the stacked fins 4 and the hairpin tubes 3 are fixed together, and the tube openings 31 of the hairpin tubes 3 are further expanded. The tube expansion continues until the piping attachment shape 5 is formed, a shape to which the piping can be attached.

[0016] Next, in Step 4, with the stacked fins 4 and hairpin tubes 3 fixed together, the refrigerant pipes 6 are attached to the pipe attachment shapes 5 of the hairpin tubes 3. In this embodiment, the refrigerant pipes 6 have a U-bent shape. After the refrigerant pipes 6 are attached to the hairpin tubes 3, the connection points between the hairpin tubes 3 and the refrigerant pipes 6 are fixed by brazing.

[0017] The above is an outline of the manufacturing process for a heat exchanger. After Step 4, other parts (not shown) are assembled to form a finished heat exchanger. If necessary, a bending step for the hairpin tube 3 or the refrigerant pipe 6 may be added to the manufacturing process for the heat exchanger.

[0018] Next, the tube expansion step of Step 3 in FIG. 2 will be described in detail with reference to the partially enlarged views of FIGS.

[0019] FIG. 3(a) shows a state in which one of the tube openings 31 of the hairpin tube 3 is set in the tube expanding device.

[0020] Next, as shown in Figure 3(b), the primary expansion part 7 is inserted into the opening 31 of the hairpin tube 3, and is inserted up to the vicinity of the hairpin portion 32 of the hairpin tube 3 to expand the tube. The primary expansion part 7 is a jig with a long, thin rod whose tip is inflated into the shape of an oval sphere. After the primary expansion part 7 reaches the vicinity of the hairpin portion of the hairpin tube 3, the primary expansion part 7 is then pulled out from the opening 31 of the hairpin tube 3. The hairpin tube 3 is expanded into a primarily expanded hairpin tube 3A. This process is called the primary expansion process.

[0021] Next, as shown in Figure 3(c), a secondary expansion part 8 is inserted into the opening of the primarily expanded hairpin tube 3A, which is the hairpin tube 3 expanded and formed in Figure 3(b). The secondary expansion part 8 is a jig that integrates a small-diameter cylindrical portion, a truncated cone portion, and a large-diameter cylindrical portion from the bottom as shown. When the secondary expansion part 8 is then pulled out of the opening of the primarily expanded hairpin tube 3A, a secondary expanded portion 3B is formed at the opening of the hairpin tube 3. This is the secondary expansion process.

[0022] Next, as shown in Figure 3(d), a flare expansion part 9 is inserted through the secondary expansion part 3B formed at the opening of the hairpin tube 3 in Figure 3(c). The flare expansion part 9 is a jig that integrates, from the bottom as shown, a small-diameter truncated cone part, a small-diameter cylindrical part, a large-diameter truncated cone part, and a large-diameter cylindrical part. When the flare expansion part 9 is then pulled out of the opening, a flare expansion part 3C is formed at the opening of the hairpin tube 3. This is referred to as the flaring process. The secondary expansion part 3B and the flare expansion part 3C expanded and formed in Figures 3(c) and 3(d) form the pipe mounting shape 5 described above.

[0023] Next, the primary tube expanding step will be described in more detail. First, the configuration of the chuck mechanism 500 used in the primary tube expanding step will be described with reference to FIGS.

[0024] 4(a), 4(b), and 4(c), which is a cross-sectional view taken along line A-A in FIG. 4(a), show the chuck mechanism 500. The chuck mechanism 500 is a mechanism for gripping the hairpin tube 3, and includes a chuck fixing and operating mechanism 100, a sleeve 110, and a chuck 120.

[0025] The chuck fixing / operating mechanism 100 includes a sleeve holding mechanism 101 and a chuck holding mechanism 102. The sleeve holding mechanism 101 holds the upper end of the sleeve 110. The chuck holding mechanism 102 holds the upper end of the chuck claw sliding part 170 of the chuck 120. The sleeve holding mechanism 101 is movable up and down relative to the chuck holding mechanism 102. The sleeve holding mechanism 101 grips the hairpin tube 3 by moving downward, and releases the grip by moving upward.

[0026] The sleeve 110 is a hollow cylindrical member. The outer periphery of the upper end of the sleeve 110 is fixed to the sleeve holding mechanism 101 by a method selected from fitting, adhesive, set screws, etc. The inner periphery of the lower end of the sleeve 110 is formed with a guide surface 111 having a tapered cross section as shown in FIG. 4( a).

[0027] The chuck 120 includes a chuck jaw sliding part 170 and a chuck jaw 160 .

[0028] The chuck jaw sliding part 170 is a hollow cylindrical part and is disposed inside the sleeve 110. The outer periphery of the upper end of the chuck jaw sliding part 170 is fixed to the chuck holding mechanism 102 by a method selected from fitting, adhesive, set screws, etc. As shown in FIG. 5 , the chuck jaw sliding part 170 has slits 171 formed on its cylindrical side surface through which the chuck jaws 160 slide. Six slits 171 are disposed radially and equidistantly around the circumferential direction of the chuck jaw sliding part 170. In addition, a tapered surface 172 having a tapered cross section as shown in FIG. 4( a) is formed on the inner periphery of the lower end of the chuck jaw sliding part 170.

[0029] The chuck jaws 160 are arranged in slits 171 of the chuck jaw sliding part 170 so as to be slidable in the radial direction of the chuck jaw sliding part 170. The chuck jaws 160 have a rectangular block shape with a notch added to form a tapered surface 162.

[0030] Each chuck jaw 160 includes a gripping portion 161 having a surface for gripping the hairpin tube 3, and a tapered surface 162 guided by the guide surface 111 of the sleeve 110. The gripping portion 161 has a surface for gripping the hairpin tube 3. The tapered surface 162 faces upward from the radially outer side when six chuck jaws 160 are arranged, and is disposed to face the guide surface 111 of the sleeve 110. The tapered surface 162 is guided by the guide surface 111 of the sleeve 110. As shown in FIG. 4A , the upper portion of the tapered surface 162 of each chuck jaw 160 and the lower portion of the tapered guide surface 111 of the sleeve 110 overlap in the height direction. This prevents each chuck jaw 160 from coming off the chuck jaw sliding part 170.

[0031] The gripping portion 161 of the chuck jaw 160 can have various shapes, as shown in Figures 6(a) to 6(c) for example. The linear chuck jaw 160A, V-shaped chuck jaw 160B, convex chuck jaw 160C, and concave chuck jaw 160D shown in Figures 6(a) to 6(d) each include a gripping portion 161. The gripping portion 161 of the linear chuck jaw 160A has a linear flat surface when viewed in the axial direction of the gripped hairpin tube 3. The gripping portion 161 of the V-shaped chuck jaw 160B has a V-shaped groove surface that opens toward the hairpin tube 3 when viewed in the axial direction of the gripped hairpin tube 3. The gripping portion 161 of the convex chuck jaw 160 has a convex surface that is circumferentially convex toward the hairpin tube 3 when viewed in the axial direction of the gripped hairpin tube 3. The gripping portion 161 of the concave chuck jaw 160D has a concave surface that is circumferentially convex toward the hairpin tube 3 when viewed in the axial direction of the gripped hairpin tube 3.

[0032] In the first to fourth embodiments for gripping the hairpin tube 3 having a circular cross section, the guide surface of the sleeve and the tapered surface of the chuck jaw sliding part are truncated cone-shaped surfaces with a tapered cross section along the axial direction. Also, the tapered surface of the chuck jaw that contacts the guide surface is tapered in cross section along the axial direction, but is a rounded surface that fits the guide surface.

[0033] Next, the primary tube expansion process of the heat exchanger according to the first embodiment of the present disclosure will be described with reference to the flowchart of Figure 7, Figures 8(a) to 8(c), and Figures 9(a) to 9(c). In the following description, it is assumed that the tube opening 31 of the hairpin tube 3 opens upward.

[0034] First, as shown in Fig. 8(a), the laminated fin 4 and the hairpin tube 3 before the primary expansion are set in an assembled state on a pallet 15 (step S10). The "work" in Fig. 7 indicates the combination of the laminated fin 4 and the hairpin tube 3. At this time, the laminated fin 4 before the primary expansion and the hairpin tube 3 are fixed in their assembled state in the depth direction and lateral direction as shown using a heat exchanger fixing part 13. Next, the hairpin fixing part 14 is set on the hairpin portion 32 of the hairpin tube 3 (step S20).

[0035] Prior to step S30, the required number of primary tube expansion parts 7 are set above the fixed hairpin tube 3 and coaxially with the hairpin tube 3. Similarly, the sleeve 110 and chuck 120 of the chuck mechanism 500 are set above the fixed hairpin tube 3 and coaxially with the hairpin tube 3. The sleeve 110 and chuck 120 for fixing the tube opening 31 of the hairpin tube 3 are attached to the chuck fixing and operating mechanism 100.

[0036] Next, as shown in Figure 8(b), the chuck mechanism 500 descends from its initial position to a predetermined position (step S30). At this time, as shown in Figure 9(a), even if the position of the hairpin tube 3 varies due to the taper of the tapered surface 172, the hairpin tube 3 is guided into the chuck jaw sliding component 170. The tube opening 31 of the hairpin tube 3 then protrudes from the upper end of the chuck jaws 160. This allows the chuck 120 to grip and fix the tube opening 31 of the hairpin tube 3. The primary tube expansion component 7 then descends to near the tube opening 31 of the hairpin tube 3.

[0037] 9(b), the primary tube expansion part 7 descends from the lower end of the chuck jaws 160 (step S40). At this time, the primary tube expansion part 7 performs primary tube expansion from the direction of the tube opening 31 of the hairpin tube 3.

[0038] 9(c), the sleeve 110 of the chuck fixing / operating mechanism 100 of the chuck mechanism 500 is lowered, and the chuck claws 160 grip the hairpin tube 3 (step S50). As the sleeve 110 is lowered, the tapered surfaces 162 of the chuck claws 160 held by the chuck claw sliding parts 170 come into contact with the guide surfaces 111 of the sleeve 110. As the sleeve 110 is further lowered, the chuck claws 160 slide relative to the chuck claw sliding parts 170, guided by the guide surfaces 111, toward the hairpin tube 3. The chuck claws 160, pressed against the outer peripheral surface of the hairpin tube 3, grip the tube opening 31 of the hairpin tube 3.

[0039] Next, the primary tube expansion part 7 is lowered to the hairpin portion 32 (step S60). At this time, the primary tube expansion part 7 further expands the tube to the hairpin portion 32, and reaches the position shown in FIG.

[0040] After the tube has been expanded to the end position, the sleeve 110 rises, and the chuck claws 160 release their grip, releasing the hairpin tube 3 (step S70).

[0041] Next, as shown in Figure 8(c), the primary tube expansion part 7 is raised to a predetermined position and pulled out from the hairpin tube 3 (step S80). At this time, a force that moves the hairpin tube 3 upward is generated due to friction between the hairpin tube 3 and the primary tube expansion part 7. The hairpin fixing part 14 prevents the hairpin tube 3 from moving upward against this force. In the first embodiment, the hairpin fixing part 14 is depicted as a circle. Alternatively, the hairpin fixing part 14 may have a shape that grips the hairpin portion of the hairpin tube 3 in order to prevent the hairpin tube 3 from moving upward. Alternatively, the hairpin fixing part 14 may have a shape that grips the hairpin portion of the hairpin tube 3 with a force greater than the force that moves the hairpin tube 3 upward, generating a frictional force.

[0042] 8(c), the chuck mechanism 500 is raised to its initial position (step S90). The hairpin fixing part 14 is then removed from the hairpin portion 32 (step S100). The workpiece is then removed from the pallet 15 of the tube expanding device (step S110), thereby completing the primary tube expanding process.

[0043] According to the configuration of this embodiment, when the hairpin tube 3 is first expanded, the chuck claws 160 can grip the hairpin tube 3 by making line contact or surface contact with the hairpin tube 3. This reduces deformation of the tube during expansion of the heat exchanger, allowing the heat exchanger to be expanded with high quality.

[0044] Second Embodiment In a second embodiment, as shown in FIGS. 10(a) to 10(c), a chuck 120 is provided with drop prevention chuck claws 180 instead of the chuck claws described above.

[0045] 10(a) to 10(c) are arranged in six pieces in slits 171 of the chuck jaw sliding part 170 so as to be slidable in the radial direction of the chuck jaw sliding part 170. The fall prevention chuck jaws 180 include a gripping part 181, a tapered surface 182, protrusions 183 and 184, and a jaw taper 185.

[0046] The fall prevention chuck claw 180 has a shape of a rectangular parallelepiped block with notches or protrusions added thereto to form a tapered surface 182 , protrusions 183 , protrusions 184 and a claw taper 185 .

[0047] The gripping portion 181 has a surface that grips the hairpin tube 3. The tapered surface 182 faces upward from the radially outer side when six fall prevention chuck jaws 180 are arranged, and is arranged to face the guide surface 111 of the sleeve 110. The tapered surface 182 is guided by the guide surface 111 of the sleeve 110. The protrusion 183 includes a part of the tapered surface 182 and protrudes above the fall prevention chuck jaws 180. The protrusion 184 protrudes downward from the radially outer side when six fall prevention chuck jaws 180 are arranged. The jaw taper 185 is a taper that faces downward from the radially inner side when six fall prevention chuck jaws 180 are arranged.

[0048] 10(a), the sleeve 110 moves axially downward relative to the fall prevention chuck claws 180. At this time, the fall prevention chuck claws 180 slide radially inward of the chuck claw sliding parts 170 and grip the hairpin tube 3 as shown in FIG.

[0049] In the configuration of this embodiment, the fall prevention chuck claws 180 are slid radially inward of the chuck claw sliding part 170. At this time, the cylindrical outer surface of the chuck claw sliding part 170 and the protrusions 183, 184 of the fall prevention chuck claws 180 interfere with each other, preventing the fall prevention chuck claws 180 from sliding any further inward. This makes it possible to prevent the fall prevention chuck claws 180 from falling into the cylindrical inner surface of the chuck claw sliding part 170.

[0050] Furthermore, even if the thickness of the chuck jaw sliding part 170 is thin, even if the fall prevention chuck jaws 180 are tilted, the fall prevention chuck jaws 180 are prevented from dropping into the cylindrical inner side of the chuck jaw sliding part 170. The protrusions 183, 184 of the fall prevention chuck jaws 180 prevent the fall.

[0051] 11( a ) to 11 ( d ) show diagrams of inserting the hairpin tube 3 into the chuck jaw sliding component 170. The chuck jaw sliding component 170 has a tapered surface 172. As shown in FIG. 11( a ), even if the position of the hairpin tube 3 varies due to the taper of the tapered surface 172, the hairpin tube 3 is guided to the axial center of the chuck jaw sliding component 170. Then, as shown in FIG. 11( b ), the hairpin tube 3 is inserted into the chuck jaw sliding component 170. At this time, even if the gripping portion 181, which has a surface for gripping the hairpin tube 3, is located inside the chuck jaw sliding component 170, the claw taper 185 comes into contact with the tube end of the hairpin tube 3. Due to contact with the inserted hairpin tube 3, the gripping portion 181 slides radially outward. Furthermore, as shown in FIG. 11( c ), the hairpin tube 3 moves closer to the axial center of the chuck jaw sliding component 170. Thereafter, as shown in FIG. 11( d ), the hairpin tube 3 can be inserted into the inside of the chuck jaw sliding part 170 without deforming the tube end of the hairpin tube 3 .

[0052] Therefore, according to this embodiment, the fall prevention chuck jaws 180 are prevented from dropping, making assembly easier. In addition, a large gap can be secured between the hole on the side of the chuck jaw sliding part 170 and the fall prevention chuck jaws 180, that is, tolerances can be relaxed. This makes it possible to manufacture chuck parts that can be manufactured at low cost.

[0053] 12(a) and 12(b), in the third embodiment, a chuck mechanism 500 includes a forced sliding sleeve 200 instead of the above-described sleeve, and a chuck 120 includes forced sliding chuck jaws 190 instead of the above-described chuck jaws.

[0054] The inner periphery of the forced sliding sleeve 200 is formed with an upper guide surface 201, a lower guide surface 202, and a circumferential locking surface 203. The guide surfaces 201 and 202 each have a tapered cross-sectional shape. The guide surfaces 201 and 202 each extend upward toward the radially inward direction of the forced sliding sleeve 200. This creates a circumferential groove in the forced sliding sleeve 200 that opens obliquely upward toward the radially inward direction. The circumferential locking surface 203 connects the edges of the guide surfaces 201 and 202 vertically.

[0055] The forced sliding sleeve 200 is configured to be divided into two or more parts in the axial direction, which makes it easier to assemble the forced sliding chuck jaws 190 and the chuck jaw sliding parts 170.

[0056] Six forced sliding chuck jaws 190 are arranged in slits 171 of chuck jaw sliding component 170 so as to be slidable in the radial direction of chuck jaw sliding component 170. Each forced sliding chuck jaw 190 includes a gripping portion 191 having a surface for gripping hairpin tube 3, a tapered surface 192, protrusions 193 and 194, and a tapered surface 195.

[0057] The forced sliding chuck jaws 190 have a rectangular block shape with notches or protrusions added to form a tapered surface 192 and protrusions 193 and 194. When six forced sliding chuck jaws 190 are arranged, the tapered surface 192 faces upward from the radially outer side and is guided by facing a guide surface 201 above the forced sliding sleeve 200. The protrusion 193 includes a part of the tapered surface 192 and protrudes above the forced sliding chuck jaws 190. When six forced sliding chuck jaws 190 are arranged, the protrusion 194 protrudes downward from the radially outer side.

[0058] When six forcible sliding chuck jaws 190 are arranged, the tapered surface 195 faces downward from the radially outer side and is guided by facing the guide surface 202 below the forcible sliding sleeve 200 .

[0059] Furthermore, when the forcible sliding chuck jaws 190 move radially outward of the forcible sliding sleeve 200 , they are locked by the locking surfaces 203 of the forcible sliding sleeve 200 .

[0060] 12(a), the forced sliding sleeve 200 moves downward in the axial direction relative to the forced sliding chuck jaws 190. At this time, the forced sliding chuck jaws 190 slide radially inward of the chuck jaw sliding parts 170 and grip the hairpin tube 3 as shown in FIG.

[0061] Furthermore, the forced sliding sleeve 200 moves axially upward relative to the forced sliding chuck jaws 190. At this time, the forced sliding chuck jaws 190 slide radially outward of the chuck jaw sliding parts 170, releasing the hairpin tube 3.

[0062] According to this embodiment, it is possible to control the sliding of the forced sliding chuck jaws 190, and stabilize the state of the contact points between the forced sliding chuck jaws 190 and the hairpin tube 3. This makes it possible to manufacture high-quality heat exchangers.

[0063] 13A and 13B, in the fourth embodiment, a chuck mechanism 500 includes a ball sleeve 220 instead of the above-described sleeve. Also, a chuck 120 includes ball chuck jaws 210 and ball chuck jaw sliding parts 230 instead of the above-described chuck jaws and sliding parts.

[0064] The ball sleeve 220 is formed in a hollow cylindrical shape. A guide surface 221, a guide surface 222, and a locking surface 223 are formed on the inner periphery of the ball sleeve 220. The guide surface 221 has a tapered cross-sectional shape extending upward toward the axial center of the ball sleeve 220. The guide surface 222 is a circumferential surface extending upward from the upper edge of the guide surface 221. The locking surface 223 is a circumferential surface extending downward from the lower edge of the guide surface 221.

[0065] The ball chuck jaw sliding component 230 is formed in a hollow cylindrical shape. Holes 231 through which the ball chuck jaws 210 slide are formed on the cylindrical side surface of the ball chuck jaw sliding component 230. Six holes 231 are arranged radially at equal intervals in the circumferential direction of the ball chuck jaw sliding component 230. The holes 231 are formed in a truncated cone shape with a large opening diameter on the outer peripheral surface side of the cylinder and a small opening diameter on the inner peripheral surface side.

[0066] The ball chuck jaws 210 are spherical members, and six of them are arranged in the holes 231 of the ball chuck jaw sliding part 230 .

[0067] Next, the operations of the ball chuck jaws 210, the ball sleeve 220, and the ball chuck jaw sliding parts 230 will be described.

[0068] 13(a), the hairpin tube 3 processed to the piping mounting shape 5 is placed coaxially on the chuck mechanism 500. Thereafter, the ball chuck jaws 210, the ball sleeve 220, and the ball chuck jaw sliding parts 230 are synchronously lowered in the axial downward direction.

[0069] Next, when the ball chuck jaws 210 reach the secondary tube expansion portion 3B, the ball chuck jaws 210, the ball sleeve 220, and the ball chuck jaw sliding parts 230 stop. After that, the ball sleeve 220 further descends in the axial downward direction. At this time, the ball chuck jaws 210 are guided from the guide surface 221 to the guide surface 222, and slide radially inward of the ball chuck jaw sliding parts 230, thereby gripping the tube as shown in FIG. 13(b).

[0070] According to this embodiment, the part shape is simpler, and the parts of the chuck mechanism 500 can be manufactured at low cost.

[0071] 14(a), 14(b), and 14(c), which is a cross-sectional view taken along the line B-B of FIG. 14(a), a chuck mechanism 500 includes a flat tube sleeve 250 in place of the sleeve described above to chuck the flat tube 27. Furthermore, the chuck 120 includes flat tube chuck claws 240 and flat tube chuck claw sliding parts 260 in place of the chuck claws and sliding parts described above. Furthermore, the flat tube chuck claws 240 are arranged with different sizes on the long axis portion and the short axis portion of the flat tube 27.

[0072] The flat pipe sleeve 250 is formed in a hollow cylindrical shape with a rectangular cross section. A guide surface 251 with a tapered cross section is formed on the inner periphery of the lower end of the flat pipe sleeve 250. Note that the guide surface 251 of the flat pipe sleeve 250 has four sides that are inclined flat surfaces when viewed from below.

[0073] The flat tube chuck jaw sliding component 260 is a hollow cylinder with a rectangular cross section, and is disposed inside the flat tube sleeve 250. A slit 261 is formed in the flat tube chuck jaw sliding component 260 midway along its length, allowing the flat tube chuck jaws 240 to slide along it. Four slits 261 are disposed in the center of each side surface of the flat tube chuck jaw sliding component 260. In addition, a tapered surface 262 having a tapered cross section as shown in FIG. 14( a) is formed on the inner periphery of the lower end of the flat tube chuck jaw sliding component 260.

[0074] Four flat tube chuck claws 240 are arranged in slits 261 of the flat tube chuck claw sliding part 260. The flat tube chuck claws 240 are slidable inward and outward on each side of the flat tube chuck claw sliding part 260. The flat tube chuck claws 240 have a rectangular block shape with notches added to form tapered surfaces 242. Each flat tube chuck claw 240 has a gripping portion 241 and a tapered surface 242. The gripping portion 241 has a surface that grips the flat tube 27. The tapered surface 242 is guided by a guide surface 251 of the flat tube sleeve 250.

[0075] When the four flat tube chuck jaws 240 are arranged, the tapered surface 242 faces upward from the radially outer side and is arranged to face the guide surface 251 of the flat tube sleeve 250.

[0076] As shown in FIG. 14( c ), the flat tube chuck jaws 240 are arranged with two wide flat tube chuck jaws 240A and two narrow flat tube chuck jaws 240B.

[0077] The widths of flat tube chuck claws 240A and 240B correspond to the widths of the side surfaces of flat tube sleeve 250 and flat tube chuck claw sliding part 260, respectively. Flat tube chuck claws 240A grip the outer surface of the long axis portion of flat tube 27. Flat tube chuck claws 240B grip the outer surface of the short axis portion of flat tube 27. Accordingly, flat tube chuck claw sliding part 260 has two wide slits 261 and two narrow slits 261 corresponding to flat tube chuck claws 240.

[0078] The operation of the chuck mechanism 500 according to the fifth embodiment is similar to the operation of gripping the hairpin tube 3 according to the first embodiment.

[0079] According to this embodiment, it is possible to grip the flat tubes 27 in the same way as the hairpin tubes 3, and a heat exchanger with higher performance can also be manufactured.

[0080] Although the present disclosure has been described above based on the embodiments, the present disclosure is not limited to the above-described embodiments and modifications, and various modifications and applications are possible.

[0081] In the above embodiment, the U-bent refrigerant pipe 6 is attached to the pipe attachment shape 5 of the hairpin tube 3. However, the refrigerant pipe 6 is not limited to a U-bent, and may be of other shapes and types.

[0082] In the above embodiment, the forced sliding sleeve 200 is of a divided structure. Alternatively, the forced sliding sleeve 200 may be formed as a single component.

[0083] In the above embodiment, the flat tube chuck jaw 240A of the long shaft portion is a single wide part. Alternatively, the flat tube chuck jaw 240A may be divided into two or more parts.

[0084] In the above embodiment, the guide surface is formed as a tapered surface around the entire circumference of the sleeve. Alternatively, for example, a groove corresponding to the width of the chuck jaws may be formed in the sleeve, and a flat or curved tapered surface may be formed within the groove.

[0085] In the above embodiment, the number of chuck jaws of each type for the hairpin tube 3 is six. Alternatively, the number of chuck jaws may be three or more, for example, eight. Furthermore, the arrangement of the chuck jaws does not need to be evenly spaced as long as they can secure the tube opening.

[0086] The configuration of the chuck mechanism 500 applied to the hairpin tube 3 may be combined and applied to the flat tube 27 .

[0087] In the above embodiment, a tapered surface is formed as a guide surface inside the lower side of the sleeve. Alternatively, if the chuck diameter of the chuck jaws can be reduced by moving the sleeve downward, the tapered surface may not be formed. Conversely, if the chuck diameter of the chuck jaws can be reduced by moving the sleeve downward, the tapered surface may not be formed.

[0088] In the above embodiment, the chuck jaws are provided with the protrusions in the vertical direction to prevent the chuck jaws from falling. Alternatively, the chuck jaws may be provided with protrusions in the circumferential direction, for example.

[0089] The chuck mechanism and the tube expanding method described above are not limited to the above-described embodiment, and various modifications and substitutions can be made. Various embodiments of the present disclosure will be described below as appendices.

[0090] (Note) (Note 1) A chuck mechanism comprising: a plurality of chuck jaws arranged circumferentially spaced apart on the outside of a refrigerant pipe of a heat exchanger and gripping the refrigerant pipe; a chuck jaw sliding part formed in a cylindrical shape and holding the chuck jaws so that they can slide inward and outward in the radial direction; and a sleeve formed in a cylindrical shape and sliding the chuck jaws toward the refrigerant pipe relative to the chuck jaw sliding part.

[0091] (Supplementary Note 2) The chuck mechanism according to Supplementary Note 1, wherein the chuck jaws have protrusions that prevent the chuck jaws from falling inward of the chuck jaw sliding part when sliding against the chuck jaw sliding part.

[0092] (Supplementary Note 3) The chuck mechanism according to Supplementary Note 1 or 2, wherein the chuck jaws and the sleeve each have a tapered surface that is inclined with respect to the axial direction of the refrigerant pipe and that contacts and slides against each other.

[0093] (Supplementary Note 4) The chuck mechanism according to any one of Supplementary Notes 1 to 3, wherein the chuck jaws have a spherical shape.

[0094] (Supplementary Note 5) The chuck mechanism according to any one of Supplementary Notes 1 to 4, wherein the refrigerant pipe is a flat pipe, and the chuck jaws are arranged with different sizes on a major axis portion and a minor axis portion of the flat pipe.

[0095] (Supplementary Note 6) A tube expansion method using a chuck mechanism according to any one of Supplementary Notes 1 to 5, comprising the steps of opening the refrigerant tube upward and fixing it; lowering the chuck mechanism towards the opening of the refrigerant tube; causing a tube expansion component to protrude from the lower end of the chuck mechanism and inserting the tube expansion component into the refrigerant tube from the opening to expand a portion of the refrigerant tube; lowering the sleeve of the chuck mechanism to grip the refrigerant tube with the chuck jaws; and inserting the tube expansion component further into the refrigerant tube to expand the refrigerant tube.

[0096] The present invention allows various embodiments and modifications without departing from the broad spirit and scope of the present invention. Furthermore, the above-described embodiments are intended to explain the present invention and do not limit the scope of the present invention. That is, the scope of the present invention is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of the invention equivalent thereto are considered to be within the scope of the present invention.

[0097] This application is based on Japanese Patent Application No. 2023-115510, filed on July 13, 2023. The entire specification, claims, and drawings of Japanese Patent Application No. 2023-115510 are incorporated herein by reference.

[0098] The present invention can be suitably employed in the manufacture of heat exchangers, for example.

[0099] 1 Fin, 2 Burring hole, 3 Hairpin tube, 3A Primary expanded hairpin tube, 3B Secondary expanded section, 3C Flare expanded section, 4 Stacked fin, 5 Pipe mounting shape, 6 Refrigerant pipe, 7 Primary expansion part, 8 Secondary expansion part, 9 Flare expansion part, 13 Heat exchanger fixing part, 14 Hairpin fixing part, 15 Pallet, 27 Flat tube, 31 Pipe opening, 32 Hairpin part, 100 Chuck fixing / operating mechanism, 101 Sleeve holding mechanism, 102 Chuck holding mechanism, 110 Sleeve, 111 Guide surface, 120 Chuck, 160 Chuck jaw, 160A Linear shaped chuck jaw, 160B V-shaped chuck jaw, 160C Convex shaped chuck jaw, 160D Concave shaped chuck jaw, 161 Grip part, 162 Tapered surface, 170: Chuck jaw sliding part, 171: Slit, 172: Tapered surface, 180: Fall prevention chuck jaw, 181: Grip part, 182: Tapered surface, 183: Protrusion, 184: Protrusion, 185: Tapered jaw, 190: Forced sliding chuck jaw, 191: Grip part, 192: Tapered surface, 193: Protrusion, 194: Protrusion, 195: Tapered surface, 200: Forced sliding sleeve, 201: Guide surface, 202: Guide surface, 203: Locking surface, 210: Ball chuck jaw, 220: Ball sleeve, 221, 222: Guide surface, 223: Locking surface, 230: Ball chuck jaw sliding part, 231: Hole, 240, 240A, 240B: Flat tube chuck jaw, 241: Grip part, 242 Tapered surface, 250 flat tube sleeve, 251 guide surface, 260 flat tube chuck jaw sliding part, 261 slit, 262 tapered surface, 500 chuck mechanism.

Claims

1. a plurality of chuck jaws arranged at intervals in a circumferential direction on the outer side of the refrigerant pipe of the heat exchanger, the chuck jaws gripping the refrigerant pipe; a chuck jaw sliding component formed in a cylindrical shape and configured to hold the chuck jaws so that they can slide radially inward and outward; a sleeve formed in a cylindrical shape and sliding the chuck jaws toward the refrigerant pipe relative to the chuck jaw sliding component, After inserting the pipe expansion part into the refrigerant pipe to expand the pipe, the expanded part is gripped by the chuck jaws. Chuck mechanism.

2. The chuck jaws are provided with protrusions that prevent the chuck jaws from falling inward of the chuck jaw sliding parts when sliding against the chuck jaw sliding parts. The chuck mechanism according to claim 1 .

3. The chuck jaws and the sleeve are each provided with a tapered surface that is inclined with respect to the axial direction of the refrigerant pipe and that contacts and slides against each other. The chuck mechanism according to claim 1 or 2.

4. The chuck jaws have a spherical shape. The chuck mechanism according to claim 1 or 2.

5. The refrigerant pipe is a flat pipe, The chuck jaws are arranged with different sizes at the long axis portion and the short axis portion of the flat tube. The chuck mechanism according to claim 1 or 2.

6. The chuck claw has a flat surface with a linear shape that comes into contact with the refrigerant pipe. The chuck mechanism according to claim 1 or 2.

7. The chuck claw has a V-shaped groove surface on the surface that contacts the refrigerant pipe. The chuck mechanism according to claim 1 or 2.

8. The chuck jaws have a circumferentially convex surface that contacts the refrigerant pipe, The chuck mechanism according to claim 1 or 2.

9. The chuck jaws have a circumferentially convex concave surface that contacts the refrigerant pipe, The chuck mechanism according to claim 1 or 2.

10. The chuck claws. a first tapered surface that grips the refrigerant pipe and a second tapered surface that releases the refrigerant pipe; The chuck mechanism according to claim 1 or 2.

11. A plurality of chuck jaws are arranged circumferentially spaced apart on the outside of the refrigerant pipe of the heat exchanger, and grip the refrigerant pipe; a chuck jaw sliding component formed in a cylindrical shape and configured to hold the chuck jaws so that they can slide radially inward and outward; a sleeve formed in a cylindrical shape and causing the chuck jaws to slide relative to the chuck jaw sliding component toward the refrigerant pipe, fixing the refrigerant pipe so that it opens upward; lowering the chuck mechanism toward an opening of the refrigerant pipe; a step of projecting a tube expansion part from a lower end of the chuck mechanism and inserting the tube expansion part into the refrigerant pipe through the opening to expand a portion of the refrigerant pipe; lowering the sleeve of the chuck mechanism to allow the chuck claws to grip the refrigerant pipe, the portion of which has been expanded; and further inserting the tube expansion component into the refrigerant tube after the chuck jaws have gripped the refrigerant tube to expand the refrigerant tube. Tube expansion method.

12. The chuck claws grip the expanded portion of the tube closer to the opening than the portion into which the tube expansion part is inserted. The pipe expansion method according to claim 11.

13. A plurality of chuck jaws are arranged circumferentially spaced apart on the outside of the refrigerant pipe of the heat exchanger, and grip the refrigerant pipe; a chuck jaw sliding component formed in a cylindrical shape and configured to hold the chuck jaws so that they can slide radially inward and outward; a sleeve formed in a cylindrical shape and causing the chuck jaws to slide relative to the chuck jaw sliding component toward the refrigerant pipe, fixing the refrigerant pipe so that it opens upward; lowering the chuck mechanism toward an opening of the refrigerant pipe; a step of projecting a tube expansion part from a lower end of the chuck mechanism and inserting the tube expansion part into the refrigerant pipe through the opening to expand a portion of the refrigerant pipe; lowering the sleeve of the chuck mechanism to allow the chuck claws to grip the refrigerant pipe, the portion of which has been expanded; and further inserting the tube expansion component into the refrigerant tube after the chuck jaws have gripped the refrigerant tube to expand the refrigerant tube. A method for manufacturing a heat exchanger.

14. The chuck claws grip the expanded portion of the tube closer to the opening than the portion into which the tube expansion part is inserted. A method for manufacturing the heat exchanger according to claim 13.