JP4225287B2 - Tube expansion apparatus and heat exchanger manufacturing method - Google Patents

Description

  The present invention relates to a pipe expansion device and a method for manufacturing a heat exchanger.

In manufacture of a heat exchanger, a heat exchanger tube is passed through the fins laminated with a predetermined fin pitch. Then, a mandrel is inserted into the heat transfer tube penetrating the fins, thereby expanding the diameter of the heat transfer tube and fixing the heat transfer tube and the fin (see Patent Document 1).
JP-A-6-65415

  When the above tube expansion process is started, the heat transfer tube in which the mandrel is inserted is expanded in the outer diameter direction. That is, when the mandrel is inserted from one end of the heat transfer tube, a difference occurs between the tube diameter of the portion where the mandrel has already passed and the tube diameter of the portion where the mandrel has not yet passed. And the fin located in the outer side of a heat exchanger tube is pressed to the direction in which the spreading deformation of the heat exchanger tube has not yet arisen, ie, the other end side of a heat exchanger tube. For this reason, the fin pitch of the fin located in the other end side of a heat exchanger tube is small, the fin density of the other end side becomes larger than the fin density of the one end side, and there exists a possibility that a deviation may arise in a fin pitch. As described above, in the conventional pipe expanding device, it is difficult to make the distribution of the fin pitch into a desired mode due to the influence of the deformation of the fin during the pipe expansion.

  The subject of this invention is providing the pipe expansion apparatus which can adjust a fin pitch to a desired state in a pipe expansion process.

A tube expansion device according to a first aspect of the present invention is a heat exchanger comprising a plurality of stacked fins provided with a plurality of holes and a plurality of heat transfer tubes inserted into the holes and penetrating the fins, and inserted into the fin holes. A tube expansion device that expands a heat transfer tube to fix a fin and a heat transfer tube, and includes a first mandrel group and a second mandrel group. The first mandrel group is composed of one or more mandrels that are inserted into the heat transfer tubes and expand the heat transfer tubes to fix the heat transfer tubes and the fins. The second mandrel group, by the pre-tacking is performed is inserted into the heat transfer tube first mandrel group precedes, after the movement of the fins is restricted, it is inserted into the remaining heat transfer tubes remaining heat It consists of a plurality of mandrels that fix the remaining heat transfer tubes and fins by expanding the heat tubes.

  In this pipe expansion device, before the second mandrel group is inserted into the heat transfer tube, the first mandrel group is inserted into the heat transfer tube in advance. Thereby, the heat transfer tube in which the first mandrel group is inserted is expanded, and a part of the heat transfer tubes and the fins are temporarily fixed. For this reason, even if the 2nd mandrel group is inserted in a heat exchanger tube after insertion of the 1st mandrel group, since temporary stop is performed beforehand, movement of a fin is controlled. Thereby, in this pipe expansion apparatus, the fin pitch can be adjusted to a desired state in the pipe expansion process.

  The tube expansion device according to the second invention is the tube expansion device according to the first invention, wherein the second mandrel group is inserted into the heat transfer tube from one end side of the heat transfer tube and reaches the other end side of the heat transfer tube. After that, it is inserted into the heat transfer tube.

  In this pipe expansion device, the second mandrel group is inserted into the heat transfer tube after the first mandrel group previously inserted into the heat transfer tube reaches the other end side of the heat transfer tube. Therefore, after the temporary fixing by the first mandrel group is completed, the second mandrel group is inserted into the heat transfer tube. Thereby, the movement of the fin when the second mandrel group is inserted can be more strongly regulated.

  A tube expansion device according to a third invention is the tube expansion device of the second invention, wherein the second mandrel group is inserted into the heat transfer tube from one end side of the heat transfer tube and reaches the other end side of the heat transfer tube. Is extracted from one end of the heat transfer tube and then inserted into the heat transfer tube.

  In this pipe expansion device, after the first mandrel group previously inserted into the heat transfer tube is extracted from the heat transfer tube, the second mandrel group is inserted into the heat transfer tube. That is, after the reciprocation of the first mandrel group is completed, the reciprocation of the second mandrel group is performed. Therefore, when the first mandrel group and the second mandrel group are operated with the same drive source, the first mandrel and the second mandrel can be operated with a simple mechanism.

  The tube expansion device according to the fourth invention is the tube expansion device of the second invention, wherein the second mandrel group is inserted into the heat transfer tube from one end side of the heat transfer tube and reaches the other end side of the heat transfer tube. After that, it is inserted into the heat transfer tube and extracted from one end side of the heat transfer tube together with the first mandrel group.

  In this pipe expansion device, the first mandrel group is first inserted into the heat transfer tube first, then the second mandrel group is inserted into the heat transfer tube, and both the first mandrel group and the second mandrel group are extracted from the heat transfer tube. It is. For this reason, in this pipe expansion apparatus, the time required for the cycle from the insertion of the first mandrel group and the second mandrel group to the completion of the extraction can be shortened.

  A tube expansion device according to a fifth aspect of the present invention is the tube expansion device of the first aspect, wherein the second mandrel group is such that the first mandrel group inserted into the heat transfer tube from one end side of the heat transfer tube reaches the other end side of the heat transfer tube. Before being inserted into the heat transfer tube.

  In this pipe expansion device, the second mandrel group is inserted into the heat transfer tube in succession before the first mandrel group previously inserted into the heat transfer tube reaches the other end side. That is, the second mandrel group is inserted into the heat transfer tube in the middle of the first mandrel group being inserted from one end side toward the other end side. For this reason, in this pipe expansion apparatus, the time required for the cycle from the insertion of the first mandrel group and the second mandrel group to the completion of the extraction can be shortened.

  A tube expansion device according to a sixth aspect of the present invention is the tube expansion device according to any one of the first to fifth aspects, wherein the drive unit drives the first mandrel group and the second mandrel group, and the control unit controls the drive unit. And further comprising.

  In this tube expansion device, the operation of the first mandrel group and the second mandrel group is controlled by the control unit. Thereby, the operation of inserting the first mandrel group and the second mandrel group into the heat transfer tube can be performed with higher accuracy.

According to a seventh aspect of the present invention, there is provided a heat exchanger manufacturing method comprising: a plurality of fins that are provided with a plurality of holes and stacked; and a plurality of heat transfer tubes that are inserted into the holes and penetrate the fins. Is a method of manufacturing a heat exchanger in which a heat transfer tube is inserted to expand the heat transfer tube to fix the heat transfer tube and the fin, and includes a first step and a second step. In the first step, a part of the plurality of mandrels is inserted into the heat transfer tube in advance to temporarily fix the heat transfer tube and the fin, thereby restricting the movement of the fin . In the second step, after the first step, the remaining mandrels are respectively inserted into the remaining heat transfer tubes to fix the remaining heat transfer tubes and the fins.

  In this heat exchanger manufacturing method, a part of the mandrel group is inserted into the heat transfer tube in advance, and then the remaining mandrels are inserted into the heat transfer tube. Thereby, a part of the heat transfer tubes and the fins are temporarily fixed, and then the remaining heat transfer tubes are expanded. Therefore, when the remaining mandrels are inserted into the heat transfer tubes, the temporary movement is performed in advance, so that the movement of the fins is restricted. Thereby, in this heat exchanger manufacturing method, the fin pitch can be adjusted to a desired state in the pipe expansion process.

  In the tube expansion device according to the first aspect of the present invention, the movement of the fins is regulated by temporary fixing by the first mandrel group in advance, so that the fin pitch can be adjusted to a desired state in the tube expansion process.

  In the tube expansion device according to the second aspect of the present invention, after the temporary fixing by the first mandrel group is completed, the second mandrel group is inserted into the heat transfer tube, so that the movement of the fin when the second mandrel group is inserted is more strongly Can be regulated.

  In the tube expansion device according to the third aspect of the invention, since the reciprocating motion of the second mandrel group is performed after the reciprocating motion of the first mandrel group is completed, the first mandrel group and the second mandrel group are operated by the same drive source. In this case, the first mandrel and the second mandrel can be operated with a simple mechanism.

  In the tube expansion device according to the fourth aspect of the present invention, the time required for the cycle from the insertion of the first mandrel group and the second mandrel group to the completion of the extraction can be shortened.

  In the tube expansion device according to the fifth aspect of the present invention, the time required for the cycle from the insertion of the first mandrel group and the second mandrel group to the completion of the extraction can be shortened.

  In the tube expansion device according to the sixth aspect of the invention, the operation of inserting the first mandrel group and the second mandrel group into the heat transfer tube can be performed with higher accuracy.

  In the heat exchanger manufacturing method according to the seventh aspect of the invention, first, a part of the heat transfer tubes and the fins are temporarily fixed, and then the remaining heat transfer tubes are expanded, thereby restricting the movement of the fins. Therefore, the fin pitch can be adjusted to a desired state in the pipe expansion process.

<First Embodiment>
<Structure of tube expansion device>
A tube expansion device 1 according to a first embodiment of the present invention is shown in FIG. The tube expansion device 1 is a device that expands a heat transfer tube penetrating a fin and fixes the heat transfer tube and the fin in the manufacturing process of the heat exchanger, and the heat exchanger so that the heat transfer tube is parallel to the vertical direction. 2 is a so-called vertical tube expansion device. As shown in FIG. 2, the heat exchanger 2 expanded by the tube expansion device 1 includes two fixing plates 21 and 22, a plurality of fins 23, and a plurality of heat transfer tubes 24. The two fixed plates 21 and 22 are provided in parallel with each other in the vicinity of the end of the heat exchanger 2, and a hole through which the heat transfer tube 24 passes is provided. The plurality of fins 23 are stacked in parallel between the two fixing plates 21 and 22, and a plurality of holes through which the heat transfer tubes 24 pass are provided. The plurality of fins 23 each have a rectangular shape having a long end portion of two sides and a short end portion of two sides. In the tube expansion device 1, the fins 23 are arranged so that the long end portions of the two sides are aligned in the front-rear direction and the short end portions of the two sides are aligned in the left-right direction in front view. The heat transfer tube 24 passes through the fixing plates 21 and 22 and the fins 23 perpendicular to the fixing plates 21 and 22 and the fins 23. The lower ends of the heat transfer tubes 24 are connected to each other by a U-shaped tube 25, and the upper ends are open ends. Moreover, the heat exchanger 2 which is the target of the pipe expansion process by the pipe expansion device 1 is a so-called two-row heat exchanger, and the heat transfer tubes 24 are arranged in two rows as shown in FIG. That is, the heat exchanger 2 is parallel to the first straight line L1 in the first row heat transfer tube group G1 having a plurality of heat transfer tubes 24 arranged so as to be arranged at equal intervals on the first straight line L1 in the axial cross section. A second row heat transfer tube group G2 having a plurality of heat transfer tubes 24 arranged at equal intervals on the second straight line L2 and a plurality of pipes connecting the lower ends of the plurality of heat transfer tubes 24 of the first row heat transfer tube group G1 to each other. The first U-shaped tube U1, the plurality of second U-tubes U2 connecting the lower ends of the plurality of heat transfer tubes 24 of the second row heat transfer tube group G2, the lower end of the heat transfer tubes 24 of the first row heat transfer tube group G1, and the second A plurality of third U-shaped tubes U3 are connected to the lower ends of the heat transfer tubes 24 of the row heat transfer tube group G2. In addition, the diameter of the heat transfer tube 24 before the pipe expansion process is slightly smaller than the holes provided in the fins 23 and the fixing plates 21 and 22, and the heat transfer pipe 24 and the fins 23 are fixed to each other when the heat transfer pipe 24 is subjected to the pipe expansion process. The

  Returning to FIG. 1, the tube expansion device 1 includes a frame 3, a plurality of mandrels 4, a mandrel driving unit 5, a first fixing unit 6, a second fixing unit 7, and a control unit 8 (see FIG. 5).

[flame]
The frame 3 includes a base 31, a guide post 32, a mandrel guide body 33, an upper frame 34, intermediate plates 35 and 36, a rod 37, and the like. The base 31 constitutes the bottom of the frame 3, and four guide posts 32 are erected at four corners of the base 31. The guide post 32 is a columnar member extending in the vertical direction. The mandrel guide 33 is a member that guides the mandrel 4 described later, and is provided at an intermediate portion of the guide post 32. The intermediate plates 35 and 36 are members that guide the mandrel 4 in the same manner as the mandrel guide body 33, and have a first intermediate plate 35 and a second intermediate plate 36 that are arranged separately in the vertical direction. The intermediate plates 35 and 36 are provided between the mandrel guide body 33 and the upper frame 34 so as to be slidable with respect to the guide post 32, and are connected to each other by a rod 37. The mandrel guide body 33 and the intermediate plates 35 and 36 are provided with a hole through which the mandrel 4 passes at a position corresponding to the mandrel 4, and the mandrel 4 inserted into the hole is restricted from moving in the horizontal direction. 4 is supported. The upper frame 34 constitutes the top of the frame 3 and the upper end of the guide post 32 is connected and fixed.

[Mandrel]
The mandrels 4 are members inserted into the heat transfer tubes 24, and a plurality of mandrels 4 are provided corresponding to the number of the plurality of heat transfer tubes 24. Each of the plurality of mandrels 4 has a bar shape parallel to the vertical direction, and is provided so as to be movable in the vertical direction. A head portion 41 to be inserted into the heat transfer tube 24 is provided at the lower end of the mandrel 4, and the head portion 41 has a spherical shape with a larger diameter than other portions.

[Mandrel drive]
The mandrel driving unit 5 is a mechanism that moves the mandrel 4 in the vertical direction. In addition to moving all of the mandrels 4 at the same time, it is also possible to move each mandrel 4 separately. The mandrel driving unit 5 includes a main cylinder 51, a transmission mechanism 52, a plurality of pressing members 53, and the like.

  The main cylinder 51 is fixed to the upper frame 34 and has a cylinder body 54 that can be driven in the vertical direction.

  The transmission mechanism 52 transmits the movement of the cylinder body 54 to the pressing member 53. The transmission mechanism 52 is controlled by the control unit 8 and can select a part of the pressing members 53 from the plurality of pressing members 53 and transmit the movement of the cylinder body 54.

  The plurality of pressing members 53 are transmitted with the movement of the cylinder body 54 by the transmission mechanism 52 and can independently reciprocate in the vertical direction. The plurality of pressing members 53 are provided corresponding to the plurality of mandrels, and the mandrel 4 is attached downward on the lower surface of the pressing member 53. When the cylinder body 54 of the main cylinder 51 is driven up and down, the transmission mechanism 52 transmits the movement of the cylinder body 54 to all or some of the pressing members 53. For this reason, the pressing member 53 moves up and down, and the mandrel 4 attached to the pressing member 53 moves up and down.

[First fixed part]
The first fixing portion 6 is a portion that holds and fixes the upper end of the heat transfer tube 24, below the mandrel guide body 33, and in the vicinity of the upper end of the heat transfer tube 24 of the heat exchanger 2 installed in the tube expansion device 1. Is provided. As shown in FIG. 2, the first fixing portion 6 is configured by a clamp body that is provided so that the upper end of the heat transfer tube 24 can be clamped from a direction perpendicular to the axis, that is, from the horizontal direction. The heat transfer tube 24 is held by sandwiching the upper end from the horizontal direction.

[Second fixing part]
Returning to FIG. 1, the second fixing portion 7 is a portion that is locked and held by the U-shaped tube 25 that connects the lower end of the heat transfer tube 24, and is installed in the tube expansion device 1 above the base 31. It is provided in the vicinity of the U-shaped tube 25 of the heat exchanger 2. The 2nd fixing | fixed part 7 has the receiving stand 71, the latching pin 72 (refer FIG. 3), and the latching pin receiving member 73 (refer FIG. 3).

  The cradle 71 is provided on the base 31, and the heat exchanger 2 installed in the pipe expansion device 1 is placed thereon. A plurality of recesses into which the U-shaped tube 25 is fitted are provided on the upper surface of the cradle 71.

  As shown in FIG. 3, the plurality of locking pins 72 are rod-like members arranged in parallel to each other and have a semicircular cross section (see FIG. 2). The plurality of locking pins 72 are provided so as to be movable at least in the horizontal direction, are respectively inserted inside the plurality of U-shaped tubes 25, and are respectively locked to the plurality of U-shaped tubes 25 to lock the U-shaped tube 25. Support each from the inside. The plurality of locking pins 72 are inserted into the U-shaped tube 25 from a direction inclined with respect to a direction perpendicular to the U-shaped tube 25. Hereinafter, a part of the plurality of locking pins 72 will be described in detail with reference to FIG. 4 which is an enlarged view of the vicinity of the U-shaped tube 25 to which the locking pins 72 are locked.

  As described above, the plurality of heat transfer tubes 24 are arranged in two rows of the first row heat transfer tube group G1 and the second row heat transfer tube group G2, and the first row heat transfer tube group G1 is arranged in the axial cross-sectional view. It has the 1st heat exchanger tube P1, the 2nd heat exchanger tube P2, the 3rd heat exchanger tube P3, and the 4th heat exchanger tube P4 arranged in order on the 1 straight line L1 at predetermined intervals. The second row heat transfer tube group G2 includes a fifth heat transfer tube P5, a sixth heat transfer tube P6, a seventh heat transfer tube P7, and an eighth heat transfer tube P8 that are arranged in order on the second straight line L2 with a predetermined interval in the axial sectional view. And have. The fifth heat transfer tube P5 is disposed away from the first heat transfer tube P1 in a direction that forms an angle α with the first straight line L1. The angle α is an angle in a range of 0 <α <90, and is about 60 degrees in FIG. The sixth heat transfer tube P6 is disposed away from the second heat transfer tube P2 in a direction that forms an angle α with the first straight line L1. The seventh heat transfer tube P7 is arranged away from the third heat transfer tube P3 in a direction that forms an angle α with the first straight line L1. The eighth heat transfer tube P8 is arranged away from the fourth heat transfer tube P4 in a direction that forms an angle α with the first straight line L1. Further, the first row heat transfer tube group G1 and the second row heat transfer tube group G2 are alternately arranged as viewed from the direction perpendicular to the first straight line L1 and the second straight line L2 (see solid arrow A1 in the figure). That is, when viewed from the direction perpendicular to the first straight line L1 and the second straight line L2, the sixth heat transfer pipe P6 is located between the first heat transfer pipe P1 and the second heat transfer pipe P2, and the seventh heat transfer pipe P7. Is located between the second heat transfer tube P2 and the third heat transfer tube P3, and the eighth heat transfer tube P8 is located between the third heat transfer tube P3 and the fourth heat transfer tube P4. In other words, the first heat transfer pipe P1 is located between the fifth heat transfer pipe P5 and the sixth heat transfer pipe P6 when viewed from the direction perpendicular to the first straight line L1 and the second straight line L2, The heat transfer tube P2 is located between the sixth heat transfer tube P6 and the seventh heat transfer tube P7, and the third heat transfer tube P3 is located between the seventh heat transfer tube P7 and the eighth heat transfer tube P8. Moreover, the 1st heat exchanger tube P1 and the 2nd heat exchanger tube P2 are connected by the 1st U-shaped tube U1. The sixth heat transfer tube P6 and the seventh heat transfer tube P7 are connected by a second U-shaped tube U2. The third heat transfer pipe P3 and the eighth heat transfer pipe P8 are connected by a third U-shaped pipe U3. Accordingly, the first U-shaped tube U1 is disposed along the first straight line L1, the second U-shaped tube U2 is disposed along the second straight line L2, whereas the third U-shaped tube U3 is disposed along the first straight line L1. And they are arranged obliquely across the second straight line L2. The plurality of locking pins 72 pass between the fifth heat transfer tube P5 and the sixth heat transfer tube P6 and are inserted into the first U-shaped tube U1 and the inner side of the second U-shaped tube U2. Is inserted into the second heat transfer pipe P2 and the third heat transfer pipe P3, passes between the seventh heat transfer pipe P7 and the eighth heat transfer pipe P8, and inside the third U-shaped pipe U3. And a third locking pin 83 that passes between the third heat transfer tube P3 and the fourth heat transfer tube P4. The plurality of locking pins 81-83 are respectively arranged at an angle α with respect to the first straight line L1, and the first locking pin 81, the second locking pin 82, and the third locking pin 83 are The first straight line L1 is inserted into the first U-shaped tube U1, the second U-shaped tube U2, and the third U-shaped tube U3 from the direction that forms an angle α. The locking pins 81-83 are inserted inside the U-shaped tube U1-U3 until the tip protrudes on the opposite side of the U-shaped tube U1-U3.

  Returning to FIG. 3, the locking pin receiving member 73 is a member that receives the tip of the locking pin 72 inserted inside the U-shaped tube 25. The locking pin receiving member 73 is provided with a plurality of holes into which the tips of the plurality of locking pins 72 inserted inside the plurality of U-shaped tubes 25 are respectively inserted. Supports the tip of the locking pin 72 inserted into the hole and restricts the movement of the locking pin 72.

[Control unit]
The control unit 8 shown in FIG. 5 can control the operation of the mandrel 4 by controlling the main cylinder 51 and the transmission mechanism 52 of the mandrel driving unit 5. The contents of control by the control unit 8 will be described in detail in the following <Operation in tube expansion processing>.

<Operation in tube expansion processing>
The operation when the tube expansion process is performed by the tube expansion device 1 according to the present embodiment will be described mainly based on FIG.

  First, in 1st step S1, the heat exchanger 2 in which the pipe expansion process is not performed is installed in the pipe expansion apparatus 1. FIG. At this time, the heat exchanger 2 is placed on the cradle 71 with the open end of the heat transfer tube 24 facing upward. In this state, the heat transfer tube 24 is positioned on the axial extension of the mandrel 4. The upper end of the heat transfer tube 24 is fixed by the clamp body of the first fixing portion 6, and the locking pin 72 of the second fixing portion 7 is fixed until the tip is inserted into the hole of the locking pin receiving base 71. Insert inside the tube 25. Thereby, installation of the heat exchanger 2 is completed. In addition, the several fin 23 is arrange | positioned so that a fin pitch may become equal over the whole perpendicular direction of the heat exchanger 2 here (refer Fig.7 (a)).

  Next, in the second step S <b> 2, the first mandrel group 11 is inserted into the heat transfer tube 24 prior to the second mandrel group 12. Here, the main cylinder 51 is driven, and the transmission mechanism 52 transmits the downward movement of the main cylinder 51 to the pressing member 53. At this time, the transmission mechanism 52 is controlled by the control unit 8 to transmit the movement of the main cylinder 51 only to some of the pressing members 53 among the plurality of pressing members 53. As a result, the first mandrel group 11 including a part of the mandrels 4 among the plurality of mandrels 4 is lowered, and the head portion 41 of the first mandrel group 11 is inserted into the heat transfer tube 24 from the upper end (FIG. 7 ( b)). At this time, the pressing member 53 to which the movement of the main cylinder 51 is transmitted is the pressing member 53 that is positioned above the first mandrel group 11 in the axial direction corresponding to the first mandrel group 11. As the first mandrel group 11, for example, several mandrels 4 inserted into the heat transfer tubes 24 located near the side of the heat exchanger 2 are selected. The number of mandrels 4 belonging to the first mandrel group 11 is much smaller than the number of mandrels 4 in the second mandrel group 12 to be inserted into the heat transfer tube 24 later. For this reason, the pressing force to the fins 23 due to the insertion of the first mandrel group 11 into the heat transfer tube 24 is much smaller than the pressing force when all the mandrels 4 are simultaneously inserted into the heat transfer tube 24. ing. For this reason, when the first mandrel group 11 is inserted, the fins 23 hardly move and the fin pitch hardly varies. The first mandrel group 11 descends to a lower limit position near the lower end of the heat transfer tube 24 and stops. Thereby, some heat transfer tubes 24 among the plurality of heat transfer tubes 24 are fixed to the plurality of fins 23, and the heat transfer tubes 24 and the fins 23 are temporarily fixed.

  Next, in the third step S <b> 3, the first mandrel group 11 is extracted from the heat transfer tube 24. Here, the main cylinder 51 is driven upward, contrary to the second step S2. The transmission mechanism 52 transmits the movement of the main cylinder 51 to the pressing member 53 corresponding to the first mandrel group 11, and the first mandrel group 11 moves upward. Thereby, the first mandrel group 11 is extracted from the upper end of the heat transfer tube 24.

  Next, in the fourth step S <b> 4, the remaining second mandrel group 12 is inserted into the heat transfer tube 24. Here, the downward movement of the main cylinder 51 is transmitted to the pressing member 53 corresponding to the second mandrel group 12 by the transmission mechanism 52. At this time, the movement of the main cylinder 51 is transmitted to all the pressing members 53. For this reason, the first mandrel group 11 as well as the second mandrel group 12 are again inserted into the heat transfer tubes 24 from the upper end, and the mandrels 4 are simultaneously inserted into all the heat transfer tubes 24. Thereafter, the plurality of mandrels 4 are inserted into the heat transfer tube 24 to the lower limit position and stopped (see FIG. 7C).

  In the fifth step S <b> 5, the second mandrel group 12 is extracted from the heat transfer tube 24. Here, the main cylinder 51 is driven upward, contrary to the third step S3, and the transmission mechanism 52 transmits the movement of the main cylinder 51 to the pressing member 53 corresponding to the second mandrel group 12, and the second The mandrel group 12 moves upward. Thereby, the second mandrel group 12 is extracted from the upper end of the heat transfer tube 24. At this time, the movement of the main cylinder 51 is transmitted to all the pressing members 53. As a result, the first mandrel group 11 is also extracted from the heat transfer tube 24 together with the second mandrel group 12, and the mandrels 4 are simultaneously extracted from all the heat transfer tubes 24.

  With the above operation, the tube expansion process is completed. When the pipe expansion process is finished, in the sixth step S6, the first fixing part 6 and the second fixing part 7 are opened, and the heat exchanger 2 is removed from the pipe expanding device 1.

  While the heat transfer tube 24 is expanded by the mandrel 4, a compressive force is applied to the heat transfer tube 24 to contract in the axial direction, that is, in the vertical direction, but the heat transfer tube is formed by the first fixing portion 6 and the second fixing portion 7. Since both ends of 24 are fixed, contraction of the heat transfer tube 24 is prevented.

<Characteristic>
(1)
In this pipe expansion apparatus 1, several heat exchanger tubes 24 and fins 23 are temporarily fixed in the pipe expansion process. For this reason, the downward movement of the fins 23 due to the deformation of the heat transfer tubes 24 is restricted by temporary fixing of some of the heat transfer tubes 24 and the fins 23. Therefore, in the pipe expansion process, the fin pitch set before the insertion of the mandrel 4 is maintained after the pipe expansion process. For this reason, when the fin pitch is set evenly before the mandrel 4 is inserted, the fin pitch can be made to approach evenly in the vertical direction in the heat exchanger 2 after the pipe expansion process. Thereby, the abnormal noise produced at the time of ventilation can be reduced. Further, the appearance quality of the heat exchanger 2 is improved.

(2)
In this pipe expansion device 1, after the first mandrel group 11 is inserted into the heat transfer tube 24 and extracted from the heat transfer tube 24, all the mandrels 4 are inserted into the heat transfer tube 24 and simultaneously extracted from the heat transfer tube 24. For this reason, the main cylinder 51 as a power source only needs to perform a monotonous reciprocating motion, and the operation of the mandrel 4 can be controlled by a simple configuration of the transmission mechanism 52.

Second Embodiment
In the first embodiment, the second mandrel group 12 is inserted after the first mandrel group 11 is extracted, but the second mandrel group 12 is the upper end of the heat transfer tube 24. After being inserted into the heat transfer tube 24 from the side and reaching the lower limit position, the first mandrel group 11 may be inserted into the heat transfer tube 24 before moving upward. Thereafter, the second mandrel group 12 is extracted from one end side of the heat transfer tube 24 together with the first mandrel group 11. About another structure, it is the same as that of 1st Embodiment.

  Even if such control is performed, the fin pitch before insertion into the heat transfer tube 24 can be maintained because the heat transfer tube 24 and the fins 23 are temporarily fixed in the same manner as described above. Moreover, in the control in this embodiment, the extraction step of the first mandrel group 11 can be omitted as compared with the first embodiment. For this reason, the time required in the cycle of the tube expansion process can be shortened.

<Third Embodiment>
In the first embodiment, the second mandrel group 12 is inserted after the first mandrel group 11 is extracted. However, the second mandrel group 12 is connected to the heat transfer tube 24 from the upper end side of the heat transfer tube 24. The inserted first mandrel group 11 may be inserted into the heat transfer tube 24 before reaching the lower limit position. Thereafter, the extraction of the first mandrel group 11 and the second mandrel group 12 may be performed separately, or the first mandrel group 11 that has reached the lower limit position first is the second mandrel group 12 is the lower limit position. The first mandrel group 11 and the second mandrel group 12 may be withdrawn from the heat transfer tube 24 at the same time. Other configurations are the same as those in the first embodiment.

  Even if such control is performed, the fin pitch before insertion into the heat transfer tube 24 can be maintained because the heat transfer tube 24 and the fins 23 are temporarily fixed in the same manner as described above. Further, in the control in the present embodiment, the time during which one of the first mandrel group 11 and the second mandrel group 12 is at rest is shorter than in the first embodiment. For this reason, the time required in the cycle of the tube expansion process can be shortened.

<Other embodiments>
(1)
In the first embodiment, the fin pitch is set to be equal before the tube expansion process in order to make the fin pitch close to each other. However, the fin pitch is not limited to the case where the fin pitch is equalized. It may be set differently. For example, before the pipe expansion process, the fins 23 are arranged densely in the upper part of the heat exchanger 2, and the fins 23 are arranged sparsely in the lower part of the heat exchanger 2. In this state, temporary fixing by the first mandrel group 11 is performed, and tube expansion processing is performed. Thereby, the fin pitch before the pipe expansion process is maintained after the pipe expansion process, and the heat exchanger 2 in which the upper fins 23 are dense and the lower fins 23 are sparse is manufactured. Thus, by adjusting the setting of the fin pitch before the tube expansion process, the distribution of the fin pitch can be adjusted to a desired mode.

(2)
In the above-described embodiment, the mandrel 4 located near the both side ends of the heat exchanger 2 is used as the first mandrel group 11, but the mandrel 4 located near the center of the heat exchanger 2 may be used. Good. Moreover, both the mandrel 4 located near the both ends of the heat exchanger 2 and the mandrel 4 located near the center of the heat exchanger 2 may be used as the first mandrel group 11.

(3)
Although the vertical tube expansion device 1 is shown in the above embodiment, the present invention can also be applied to a horizontal tube expansion device in which the heat transfer tubes 24 are arranged in parallel in the horizontal direction.

(4)
In the above embodiment, the locking pin 72 has a semicircular cross-sectional shape, but may have a circular cross section.

(5)
In the operation in the above tube expansion process, when the pressure frame 52 rises to the upper limit position and the first fixing portion 6 is opened, the first fixing portion 6 operates integrally with the mandrel guide body 33 and moves upward. Accordingly, the first fixing unit 6 may be temporarily retracted. In this case, the first fixing portion 6 moves downward together with the mandrel guide 33 to sandwich the heat transfer tube 24.

  INDUSTRIAL APPLICABILITY The present invention has an effect that the fin pitch can be adjusted to a desired state in tube expansion processing, and is useful as a method for manufacturing a tube expansion device and a heat exchanger.

The front view of a pipe expansion apparatus. The heat exchanger which receives a pipe expansion process, and its surrounding block diagram. The bottom view of a heat exchanger and a 2nd fixing | fixed part. The enlarged view near the 2nd fixed part. The control block diagram of a pipe expansion apparatus. The flowchart of a pipe expansion process. The schematic diagram which shows the operation | movement of the mandrel in a pipe expansion process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tube expansion apparatus 2 Heat exchanger 4 Mandrel 5 Mandrel drive part (drive part)
8 Control Unit 11 First Mandrel Group 12 Second Mandrel Group 23 Fin 24 Heat Transfer Tube S2 Second Step (First Step)
S4 4th step (2nd process)

Claims (7)

In the heat exchanger (2) including a plurality of fins (23) provided with a plurality of holes and stacked, and a plurality of heat transfer tubes (24) inserted into the holes and penetrating the fins (23), the fins ( 23) a tube expansion device for expanding the heat transfer tube (24) inserted in the hole of 23) and fixing the fin (23) and the heat transfer tube (24),
A first mandrel composed of the one or more mandrels (4) that is inserted into the heat transfer tube (24) and fixes the heat transfer tube (24) and the fins (23) by expanding the heat transfer tube (24). A group (G1);
By the first mandrel group (G1) inserted beforehand temporarily fixed to the heat transfer tube preceded by (24) is performed, after the movement of the fins (23) is restricted, the remaining of the heat transfer tube ( the remaining of the heat transfer tube by being inserted into the 24) to be expanded pipe rest of the heat transfer tube (24) (24) and the fins (23) and the second mandrel group composed of a plurality of mandrels (4) for securing the (G2),
A tube expansion device (1). In the second mandrel group (G2), the first mandrel group (G1) is inserted into the heat transfer tube (24) from one end side of the heat transfer tube (24) to the other end side of the heat transfer tube (24). After reaching the heat transfer tube (24),
The tube expansion device (1) according to claim 1. The second mandrel group (G2) is inserted into the heat transfer tube (24) from one end side of the heat transfer tube (24) and reaches the other end side of the heat transfer tube (24) (G1). ) Is extracted from one end of the heat transfer tube (24) and then inserted into the heat transfer tube (24).
The tube expansion device (1) according to claim 2. In the second mandrel group (G2), the first mandrel group (G1) is inserted into the heat transfer tube (24) from one end side of the heat transfer tube (24) to the other end side of the heat transfer tube (24). After reaching, it is inserted into the heat transfer tube (24) and extracted from one end side of the heat transfer tube (24) together with the first mandrel group (G1).
The tube expansion device (1) according to claim 2. In the second mandrel group (G2), the first mandrel group (G1) inserted into the heat transfer tube (24) from one end side of the heat transfer tube (24) is connected to the other end side of the heat transfer tube (24). Before reaching the heat transfer tube (24),
The tube expansion device (1) according to claim 1. A drive unit (5) for driving the first mandrel group (G1) and the second mandrel group (G2);
A control unit (8) for controlling the drive unit (5);
The tube expansion device (1) according to any one of claims 1 to 5, further comprising: In a heat exchanger (2) comprising a plurality of fins (23) provided with a plurality of holes and stacked, and a plurality of heat transfer tubes (24) inserted into the holes and passing through the fins (23), a plurality of mandrels ( 4) is a method of manufacturing a heat exchanger (2) in which the heat transfer tube (24) is expanded by inserting the heat transfer tube (24) into the heat transfer tube (24) to fix the heat transfer tube (24) and the fin (23). And
Temporarily fixing the heat transfer tube (24) and the fin (23) by inserting a part of the mandrels (4) among the plurality of mandrels (4) into the heat transfer tube (24) in advance. A first step (S2) for restricting movement of the fin (23) ;
After the first step (S2), the remaining mandrel (4) is inserted into the remaining heat transfer tube (24) to fix the remaining heat transfer tube (24) and the fin (23). A second step (S4);
The manufacturing method of a heat exchanger (2) provided with.

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