JPS6411376B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pipe end processing device for a heat exchanger, and in particular, the present invention relates to a tube end processing device for a heat exchanger. The present invention relates to a device that performs high-quality processing without cracking or entrainment of the flare portion.

[Conventional technology]

In a conventional heat exchanger, a hairpin-shaped tube 11 made of a material with good thermal conductivity, such as copper or aluminum, is passed through a hole 12 in which strip-shaped thin plates 10, also made of copper or aluminum, called fins are stacked, and the tube is expanded. It has a fixed structure.

FIG. 3 shows a partial cross section of the heat exchanger, showing a state in which a hairpin-shaped tube 11 is passed through the hole of the fin 10 and fixed by tube expansion. Since the passage within the pipe 11 must run from the inlet 2 to the outlet 3, the ends of the pipe are connected by a bend pipe 13. For this reason, the tube end of the hairpin-shaped tube 11 is fixed by fins and tube expansion, and then flared and the bent pipe 13 is inserted and brazed.

Further, the flared shape of the tube end is required to have strict dimensional accuracy in order to ensure brazing strength and to facilitate the brazing work.

However, in conventional tube end flaring, a flaring device is installed in a machine that expands the hairpin-shaped tube and the fins, which are made by stacking strips of thin plates, and performs both tube expansion and flaring. Ta. The flaring process was performed by simply pressing a tool with a conical tip using a hydraulic cylinder or the like that is separate from the driving means for performing the tube expansion process. An overall view of the machine that performs this tube expansion and flaring process will be explained with reference to FIG. 4. Tube expansion head 1
A spherical bullet 16 is fixed to the tip of a mandrel 15 attached to the mandrel 4. The mandrel 1
5 is long and deflects due to its own weight and thrust, so it is supported by the support 17 and prevented from deflecting. The flare head 18 is located in the center of the machine, and the mandrel 15 passes through it, and a flare tool 19 is fixed concentrically therewith, and is operated by a flare head hydraulic drive means 20 consisting of a piston and a large diameter cylinder. It's summery. Fin 1 which is a processed product
0 and the heat exchanger 1 in which the tubes 11 are temporarily assembled are placed on the table 2.
1, receiver 22, side block 2
3, and is held down from above by a clamp cylinder 25 via a holding plate 24. Next, when the start button is pressed to operate this device, the tube expansion head 14 and flare head 18 move forward at the same time, and eventually the bridge 16 is pushed into the tube 11 to expand the tube, but the flare head 18 is under low hydraulic pressure. Flare tool 1 because the downward thrust is minimized.
When the tip of the tube 9 comes into contact with the tube 11, it is no longer possible to move forward, and the tube moves forward by the amount of contraction of the tube due to tube expansion. On the other hand, the mandrel 15 continues to move forward, and as shown in FIG.
The oil pressure of the flare head hydraulic drive means 20 is switched to a high pressure, and the flare head 18 is advanced to perform flare processing on multiple axes at the same time. By the way, as shown in FIG. 6, the tube expansion process for fixing the fin 10 to the tube 11 is performed using a spherical bullet 1 that is slightly larger than the inner diameter of the tube.
6, the length 27 of the tube after expansion is shorter than the length 26 of the tube before expansion, and this difference 28 is called the amount of contraction. The amount of shrinkage varies depending on the expansion allowance, the lubrication situation inside the pipe, etc. When expanding and flaring with conventional equipment, the total length of the pipe is different, as shown in Figure 7, and therefore the flaring is also difficult. Good molding 11a, insufficient molding 11b, 11c, excessive molding 11d, impossible molding 1
1e and 11f, which not only makes it impossible to keep the flare dimensions within the specified value, but also causes cracks 3 at the tip of the flare, as shown in b and c in Figure 8.
0 and 31 defects occurred, which caused problems in terms of accuracy and quality.

Although the tube shrinks over the entire length of the tube being expanded, the tube expansion process is performed simultaneously on multiple axes, so the fins are fixed at equal intervals while being shifted, so the joint between the tube and fins will not be broken. .

Therefore, in order to perform high-quality machining with high dimensional accuracy and without flaring defects, it is necessary to always use the flaring tool 19 during tube expansion, even if the cut length of the tube or the length difference due to tube expansion is different. The tip of each flare tool 19 must be brought into contact with the pipe end, but in conventional machines, the flare head moves all the flare tools together by the same amount without individually controlling the amount of movement of the multiple flare tools. Therefore, the tip of the flare tool does not come into contact with the tube end in the same way.

In addition, related to these
No. 34839, Japanese Unexamined Patent Publication No. 57-56122, Utility Model Application No. 57-76934
There are numbers, etc.

[Problem to be solved by the invention]

The above conventional technology does not take into consideration irregularities in the tube ends, and when flaring the tube ends of a heat exchanger is performed using multi-axis simultaneous machining, this may occur due to variations in dimensions when cutting the tubes or when the tubes shrink during expansion. It was not possible to accurately follow the flare tool. Therefore, since the length of each tube end is different during flaring, it is not possible to obtain a flare shape with a predetermined size, and moreover, many defects such as cracking and curling of the flare portion occur.

An object of the present invention is to provide a heat exchanger that can form a predetermined flare shape without defects such as cracking or entrainment of the flare portion even if the length of the tube end of the heat exchanger varies and becomes irregular. The purpose of this invention is to provide processing equipment.

[Means to solve the problem]

In order to achieve the above object, after inserting tubes into the through holes of a plurality of overlapping fins, the plurality of tubes are expanded and fixed tightly to the fins. a mandrel, a plurality of flaring tools for flaring the end of the tube provided concentrically with the mandrel, a flaring head to which the plurality of flaring tools are mounted and movable in the axial direction of the tube on a bed, a flaring head driving means, and A heat exchanger processing device comprising: a mandrel drive means; a flare tool hydraulic drive means for moving the plurality of flare tools independently and separately from movement of the flare head; and pressure receiving pressure for each of the flare tools. A hydraulic chamber provided in the section, an oil passage communicating the respective hydraulic chambers, and a hydraulic passage guiding output pressure oil of the hydraulic drive means for the flare tool to the hydraulic chamber of the respective flare tool. This is achieved by

[Effect]

The tip of the flaring tool guide is pressed with pressure increased by a hydraulic pump so that all tube ends are evenly contacted against irregularities in the tube ends prior to tube expansion and flaring.

Next, as the mandrel advances, the bullet at the tip of the mandrel is pushed into the tube from the tube end and begins to expand the tube, and immediately following this, the guide portion at the tip of the flare tool advances into the tube by hydraulic pressure.

This pressing force is not a pressing force for flaring, but is a low pressure that supports the tube end until the mandrel finishes expanding the tube and does not separate the tube from the flaring tool. After the pipe expansion is completed, the hydraulic pump circuit is shut off, the pressure in each hydraulic chamber is maintained at a low pressure, and the chambers are communicated with each other through the oil passages, and then even higher pressure oil is pumped to the entire flare head by the flare head hydraulic drive means. multiple flaring tools are advanced at the same time to flare the tube end. During this flaring process, each hydraulic chamber is communicated through an oil passage, so a uniform pressing force can be obtained.

Therefore, even if the tube ends are uneven, the flare tool moves and follows the length of each tube end and brings the tip of the guide part into contact with the tube ends, so that all tube ends are uniform. It can be processed into a flared shape without cracking or curling.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. In the figures, parts that are the same as those of the conventional one are represented by the same reference numerals, and their explanations are omitted.

Reference numeral 33 denotes an improved flare head, which in the figure has cylinder holes 33a arranged horizontally in a row into which three flare tools 32 can be movably inserted. The flare tool 32 also serves as a piston, and the diameter of the rear part (on the right side in the figure) of the flare tool 32 is narrowed so as to form a hydraulic chamber 34 when inserted into the cylinder hole 33a. 43a is an O-ring provided on the piston portion (large diameter portion), and 43b is an O-ring provided on the small diameter portion to prevent oil leakage in the hydraulic chamber 34. 35 is a clip and flare tool 3
This is provided to prevent the spread of No. 2. Further, the tip of the flare tool 32 has a guide portion 32a and a guide portion 32a.
It is composed of a secondary tube expansion section 32b and a flared section 32c, and these parts are the same as the conventional one.

Reference numeral 36 is an oil passage that communicates each hydraulic chamber 34 with each other.
The oil passage 6 may be an external pipe. 37 is an oil pump, and its discharge side is connected to a pressure oil throttle valve 3 by piping.
8 to a pressure reducing valve 39. The pressure reducing valve 39 is set to a small pressure that does not apply unreasonable force to the tube 11, so that the end of the tube 11 and the tip of the guide portion 32a of the flare tool 32 can come into contact with each other before starting the tube expansion process. Reference numeral 40 denotes a low pressure regulating valve, which is connected to the discharge side piping of the pressure reducing valve 39. 4
1 is an on-off valve, which includes a pressure reducing valve 39 and a low pressure regulating valve 40.
is arranged on the inlet side and connected to a hydraulic passage 44 that communicates with each hydraulic chamber 34 provided in the flare head 33. The hydraulic passage 44 first communicates with one hydraulic chamber 34 .

Next, each of the other hydraulic chambers 34 is sequentially communicated with the oil passage 36.

Reference numeral 42 denotes a high pressure regulating valve, which is provided to prevent damage to workpieces, tools, etc. when abnormally high pressure occurs during the process of pressing the flare head 33 with a large pressure by the flare head hydraulic drive means 20. . In this way, the hydraulic drive means 5 for the flare tool
0 is the above-mentioned hydraulic pump 37 and pressure oil throttle valve 3.
8, pressure reducing valve 39, low pressure and high pressure pressure regulating valve 40,
42 and a switching valve 41. T is an oil tank, and M is an oil pump motor. Reference numeral 47 indicates the rear end surface of the flare head 33.

Next, its effect will be explained.

Multiple fins 1 overlapped as shown in Figure 4
After inserting the pipe 11 into the through hole 0 and setting it in the processing device 1, the flare tool hydraulic drive means 50, the flare head hydraulic drive means 20, and the tube expansion head hydraulic drive means (not shown) are operated to operate the flare head. 33 and tube expansion head 14 to beds 60 and 70.
is used as a guide to move it toward the end of the tube. At this time, since the hydraulic pressure of the flare head hydraulic drive means 20 is sufficiently low to move the flare head 33, the hydraulic circuit is switched so that low pressure is supplied.

In this manner, each of the flare tools 32 advances following the progress of the mandrel 15, and moves by an amount corresponding to the unevenness of the tube ends until the tip of the guide portion 32a of each flare tool 32 comes into contact with the tube end. Eventually, the bullet 16 of the mandrel 15 is pushed into the tube 11 and a portion of the tube is expanded, and the flare tool 32 is immediately inserted into the expanded portion.
The guide portion 32a is inserted, and the flare tool 32 is further moved according to the amount of contraction of the tube.

The movement of the flare tool 32 is performed by pressurized oil pressurized by a hydraulic pump 37. That is, the pressure oil raised by the oil pump 37 is sent to the pressure reducing valve 39 through the throttle valve 38 through piping, and is used together with the pressure adjustment of the low pressure adjustment valve 40 to adjust the oil pressure to an appropriate level. will be pumped to. Since each hydraulic chamber 34 is communicated with each other through an oil passage 36, each hydraulic chamber 34 is maintained at the same pressure, and the pressure acting on the pressure receiving surface 45 of each piston is equal.

The state shown in FIG. 1 shows a state in which the mandrel 15 has advanced to partially expand the pipe, and the guide portion 32a has been pushed in immediately after the pipe expansion, and the flare tool 32 remains in this position to show the expanded pipe. It is in a state where the edges are supported. Next, when the pipe expansion is completed (see FIG. 4), the on-off valve 41 is controlled to close, cutting off the hydraulic circuit and maintaining each hydraulic chamber 34 filled with pressure oil. This state is maintained, and then the flare head hydraulic drive means 20
is controlled so that a low pressure is generated to a high pressure, and the entire flare head 33 is pressed and moved with a large force. Then, each flare tool 32
The tube advances and is pushed into the tube until it reaches the secondary tube expansion section 32b and then the flare forming section 32c, where flaring processing (see Fig. 4) is performed. If the pressure in the sealed hydraulic chamber 34 rises abnormally during flaring, the high-pressure pressure regulating valve 42 opens to discharge oil and lower the pressure.

That is, the flare head hydraulic drive means 20 moves the flare head 33 to bring the entire flare tool closer to the pipe end, and the flare tool hydraulic drive means 50 moves the flare head 33 to bring the entire flare tool closer to the pipe end.
Then, the movement of each flare tool is adjusted to accommodate the unevenness of the tube ends. Therefore, even if there are irregularities in the tube ends, complete flare forming can be achieved, and defective processing as shown in FIGS. 7 and 8 b and c will not occur.

When the pipe expansion and flaring are completed, each hydraulic circuit is released and the machine is controlled to return to its original state and stand by in order to move on to processing the next product.

〔Effect of the invention〕

Since the present invention is configured as described above, even if the tube ends are uneven, the flare tools can be positioned at appropriate positions for flaring by moving the respective flare tools. Flare molding can be processed without causing defects such as cracking or entrainment.

[Brief explanation of the drawing]

FIG. 1 is a plan sectional view and hydraulic circuit diagram of the flare tool of the present invention, FIG. 4 is an external perspective view of a conventional heat exchanger tube expansion and flaring machine; Figure 5 is a sectional view of a conventional heat exchanger with tube expansion and flaring completed; Figure 6 is an explanatory diagram of the contracted state of the pipe due to conventional pipe expansion, Fig. 7 is a diagram of the state after flaring processing due to the difference in the individual pipe lengths, and Fig. 8 is:
FIG. 7 is a diagram showing the state of flaring due to the difference in the contact state of the tip of the flaring tool during conventional pipe expansion. 10...Fin, 11...Pipe, 12...Fin hole, 13...Bend pipe, 14...Pipe expansion head, 15...Mandrel, 16...Brid, 1
7...Support, 18...Flare head, 19...
... Flare tool, 20 ... Hydraulic drive means for flare head, 21 ... Table, 22 ... Receiver, 2
3...Side block, 24...Press plate, 25...
...Clamp cylinder, 26...Pipe length before tube expansion, 27
... Pipe length after expansion, 28 ... Shrinkage amount, 29 ... Overall length, 30 ... Tube end flare section crack, 31 ... Tube end flare section roll-up, 32 ... Flare tool, 33 ... Flare head, 33a ... Cylinder hole, 34... Hydraulic chamber, 35... Clip, 36... Oil passage, 37
... Hydraulic pump, 38 ... Throttle valve, 39 ... Pressure reducing valve, 40 ... Low pressure adjustment valve, 41 ... Opening/closing valve,
42...High pressure pressure regulating valve, 43...O ring, 4
4...Hydraulic passage.

Claims (1)

[Claims] 1. A plurality of elongated mandrels having blits at the tips for inserting tubes into each of the through holes of a plurality of stacked fins, and then expanding the tubes and fixing the tubes in close contact with the fins; and a plurality of long mandrels concentric with the mandrels. a plurality of flaring tools for flaring the ends of the pipes provided on the pipe; a flaring head to which the plurality of flaring tools are mounted and movable in the axial direction of the pipe on the bed; a hydraulic drive means for the flare head and a hydraulic drive means for the mandrel; In a heat exchanger processing device equipped with,
A flare tool hydraulic drive means 50 that moves the plurality of flare tools independently and separately from the movement of the flare head, a hydraulic section 34 provided in a pressure receiving part of each of the flare tools, and a hydraulic chamber of each of the flare tools. A processing device for a heat exchanger, characterized in that it is provided with an oil passage 36 that communicates with the oil passage 36, and a hydraulic passage 44 that guides the output pressure oil of the hydraulic drive means for the flare tool to the hydraulic chambers of the respective flare tools.