JPH0270317A - Manufacturing method and device for internally grooved tube with unprocessed part - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method and apparatus for manufacturing internally grooved tubes with unprocessed parts for heat exchangers such as air conditioners, refrigerators, boilers, etc. The present invention relates to a method for manufacturing an internally grooved tube with an unprocessed part, which can produce an unprocessed part with a pinch and length, and an apparatus therefor.

[Background technology]

Conventionally, copper or copper alloy bare tubes, loaf-in tubes, and the like have been used as heat transfer tubes for heat exchangers. This type of transfer tube, for example, as shown in FIGS. It is widely used industrially as a so-called shell-and-tube heat exchanger that exchanges heat between two heat exchangers.
6a, as shown in FIG. 4 (bl), insert the heat transfer tube 15 into the tube plate 16a, and apply strong tube expansion force from the inside of the heat transfer tube 15 using a small diameter roll or the like to form the protrusion 15a in the recess 16b. It is common to fix by engaging.

This can be done technically easily if the inner surface of the heat exchanger tube 15 is smooth.

On the other hand, as heat transfer tubes for such shell-and-tube heat exchangers, internally grooved tubes that have high heat transfer performance even for phase-changing fluids such as fluorocarbons have recently come to be used frequently. In this case as well, the installation to the tube body 16a is done by expanding the tube in the same way, but since the inner grooved tube also has an inner groove at the expansion attachment part, when expanding the tube (in most cases, the so-called roller tube expansion method is adopted). The inner protrusions on both sides of the groove were stretched and folded, creating flakes that could have a negative impact on the equipment that makes up the refrigeration cycle.

Furthermore, the heat exchangers for room air conditioners that are currently being produced in large quantities are mainly those shown in FIG. 5(a).

(It is a fin-and-tube type as shown in BL and TC+, and the heat exchanger tube 17 is an inner grooved tube with fine spiral grooves 17a on the inner surface to improve heat transfer performance.The heat exchanger tube 17 is As shown in B and C, the end thereof, which is bent into a hairpin shape and has a bell mouth expanded tube portion 21, is interconnected with other adjacent heat transfer tubes 17 via the U-pend material 18 and hard solder 19, and is connected to the air. However, since this type of heat exchanger tube 17 generally has grooves 17a over its entire length, for example, as shown in FIG. , U-bend material 1
When machining the bell mouth expanded tube portion 21 into which the bell mouth 8 is inserted, cracks are likely to occur due to the notch effect of the inner groove 17a, and when brazing by heating, the capillary force of the groove 17a is also applied, causing the hard solder 19 to break into the groove 17a. This has the disadvantage that a large amount of brazing material is required to ensure reliable brazing because it tends to flow into the pipe along the curve. Furthermore, as shown in FIG. 5 (TC), the tube wall of the outer portion 178 of the hairpin bend is stretched and thinned, so the bottom wall thickness cannot be made thinner than a certain level, and therefore the entire tube becomes thinner. There is also the disadvantage that the wall thickness must be made thicker, which increases the cost.

As a solution to this problem, a heat exchanger tube (tube with internal structure with unfinished part) has been proposed that has an unprocessed part without grooves at a constant pitch in the portion corresponding to the end and bending part of the hairpin described above. It has already been produced on an experimental scale (for example, JP-A-63-80915). The manufacturing device for this internally grooved tube with an unprocessed portion may include, for example, a pipe shrinking means for shrinking a metal pipe from the outside, and a grooving means for forming grooves from the inside of the shrunk metal pipe, or either one of them. There is a method for continuously manufacturing internally grooved tubes with unprocessed parts by providing an interrupting means for interrupting the operation at a predetermined timing. In the mass production of such heat transfer tubes, it is necessary to use a long coiled tube as the original tube, to process the internal grooves continuously, and then directly cut it into straight pieces on the same line, or to cut it directly into straight pieces on the same line. After winding it into a coil, it is returned straight on a separate line and cut.

[Problems to be Solved by the Invention] However, according to the conventional manufacturing apparatus for internally grooved pipes with unprocessed parts, the operation of the tube shrinking means or the grooving means is interrupted at a predetermined timing. However, it cannot be said that sufficient accuracy is necessarily achieved; for example, when cutting a long material into a certain length, even slight pinch errors accumulate, leading to misalignment of the cutting position, which reduces yield and This causes the inconvenience of reduced machining efficiency.

Therefore, it is an object of the present invention to provide a method and apparatus for manufacturing an internally grooved tube with an unprocessed part, which improves the precision of the length and pitch of the unprocessed part and the grooved part.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention is arranged such that when groove formation is resumed after forming a non-grooved portion by interrupting groove formation, a position having a predetermined distance from the position where the groove is to be formed is formed. Provided is a method for manufacturing an internally grooved tube with an unprocessed portion, in which groove formation is interrupted again when a non-grooved portion is detected.

In addition, in order to achieve the above object, unprocessed part detection means for detecting the unprocessed part of the metal tube is arranged at a distance corresponding to the interval between the unprocessed parts of the metal tube from the groove processing means, and Provided is an apparatus for manufacturing an internally grooved pipe with an unprocessed part, in which the operation of an interruption means is controlled by a control means based on detection of an unprocessed part by a part detection means.

That is, in the apparatus for manufacturing an internally grooved tube with an unprocessed part of the present invention, the unprocessed part detection means is arranged at a distance corresponding to the interval between the unprocessed parts of the metal tube from the grooving means, and When the unprocessed part is detected by the part detection means, the interruption means is operated to generate the next unprocessed part, so that the unprocessed part is always formed with a constant pinch, and This results in the formation of a grooved portion and a non-grooved portion of constant length. The apparatus for manufacturing an internally grooved tube with an unprocessed portion according to the present invention includes the following means.

fll Pipe shrinking means Shrinks a metal pipe with a predetermined outer diameter. For example, the tube may be contracted by rotating a plurality of rolls or balls in a planetary manner.

(2) Groove forming means A groove is formed on the inner surface of the metal tube in the pipe shrinking means. for example,
A groove is formed by rotatably inserting a floating grooved plug into the metal tube and contracting it by the tube contracting means.

(3) Interrupting means Interrupting the operation of both or one of the pipe contraction means and the groove processing means to form an unprocessed portion.

Specifically, the pipe shrinking diameter of the pipe shrinking means (for example, the diameter of the inscribed circle of a roll or sphere that rotates planetarily around the metal pipe) is increased to allow the pipe to pass through the metal pipe without performing pipe shrinking work. Alternatively, the grooving means, such as a grooved plug, is moved away from the pipe shrinking means and the grooving is interrupted. For this purpose, one or both of the above-mentioned parts are displaced in the axial direction by a motor or the like.

(4) Unmachined part detection means Disposed on the same axis as the grooving means such as a grooved plug and at a distance corresponding to the unmachined part interval in the direction of movement of the metal tube, and interrupting the grooving by the interruption means. Detects the unprocessed part formed by the process and outputs an unprocessed part detection signal.

(5) Control means controls the interrupting means based on the unprocessed portion detection signal. Specifically, the unprocessed part detection signal that detects the tip of the unprocessed part operates the interrupting means to form the unprocessed part, and the unprocessed part detection signal that detects the end of the unprocessed part operates the interrupting means. The operation of the groove is stopped and the formation of the grooved portion is started.

〔Example〕

The method and apparatus for manufacturing an internally grooved tube with an unprocessed portion according to the present invention will be explained in detail below.

FIG. 1 shows an embodiment of the present invention, in which a floating plug 2a and a grooved plug 2b with fine grooves for forming internal grooves on the surface are installed inside a long bare metal tube 1, which is the original tube. Insert the rotatably attached plug unit 2 via 2C. The plug unit 2 is held in place by the engagement of the floating plug 2a with the drawing die 3. The drawing die 3 is attached to a moving device 5 for axial movement via a die holder 4 provided with a stopper 4a whose axial position can be finely adjusted. The metal tube 1 is contracted by a plurality of planetary rotating balls 6 at the position of the grooved plug 2b to form a groove on the inner surface, and is continuously grooved by being pulled out in the axial direction. The ball 6 is rotated in a star shape around the outer periphery of the metal tube 1 by a rotary head 8 attached to a shaft 7 which is rotatably fixed to a pedestal 7a via a bearing 7b and rotated by a rotary drive device 7C.

At this time, the plurality of balls 6 are placed between them and are kept from contacting each other by a retainer 9. In addition, the diameter of the tube when the tube is contracted by rotating the ball 6 is determined by a transfer surface 8a provided on the rotating head 8 whose inner diameter gradually changes in the axial direction, and a rotatably attached to the die holder 4 via a bearing 10. It is adjusted by the pusher 11 which is attached. The axial pressing force of the bushing 11 against the ball 6 for the tube shrinking process is the same as that of the metal tube 1.
is given by the plastic deformation resistance and frictional force when passing through the drawing die 3. When the pusher 11 and the grooved plug 2b are moved backward (in the direction of the solid line arrow) by operating the moving device 5 and retracting the drawing die 3 while processing the inner surface groove of the metal tube l, as shown in FIG. 2(a), An unprocessed portion 1a having a slightly larger outer diameter and no groove on the inner surface is formed.

A detection sensor (for example, an eddy current detection coil, etc.) that detects this unprocessed portion 1a and outputs a detection signal 12 is placed on the same straight line as the inner grooved portion at a predetermined distance 1lII from the ball 6! .

(corresponding to the length of the grooved part), and based on the detection signal detected by the control unit 13 from the tip of the unprocessed part 1a, the moving device 5 is operated to move the pusher 11.
Then, the grooved plug 2b is moved backward, and based on the detection signal that detects the rear end of the unprocessed part 1a, the operation of the moving device 5 is reversed, and the plug 11 and the grooved plug 2b are moved forward (in the direction of the dotted arrow). ) to return it to its original position. Thereby, it is possible to repeatedly form the unprocessed portions 1a with an accurate pitch 10 and an accurate length, and there is no possibility that errors will accumulate in the pitch and length. Furthermore, a finishing die 14 is arranged behind the detection sensor 12, and a second
The unprocessed portion 1a having a large outer diameter as shown in FIG.

At this time, the length L2 of the unprocessed portion 1a becomes slightly longer due to reduction (L2 > Ll).

In addition, while the unprocessed part 1a is being contracted by the finishing die 14, the conveyance speed of the material before entering the finishing die 14 will be slightly slower, so for example, if the internal grooves are continued to be processed at this time, unnecessary grooves will be formed on the surface. Inconveniences such as curling marks appearing or the inner groove being disturbed may occur. Therefore, the unprocessed part 1a
It is desirable to interrupt the internal groove machining while the pipe is being reduced by the finishing die 14. In this embodiment, by arranging the detection sensor 12 in front of the finishing die 14, while the unprocessed part 1a is being pulled out by the finishing die 14, the internal groove machining can be reliably interrupted by the above-mentioned control. , generation of unnecessary ring marks etc. can be avoided. Therefore, the detection sensor 12 and the finishing die 14
The distance X between the detection sensor 12. Control unit 13. This distance takes into consideration the absorption of electromechanical time lag between the moving position 5 and the moving position 5. That is, finishing die 1
If the speed of the metal tube 1 when it is being pulled out at step 4 is V, then the above-mentioned time lag (and distance M ttr is ff, = V/l.Furthermore, if the delay time T is actively set, , Il, = V/ can be set to 10 V/T. In this embodiment, in order to leave the unprocessed part 1a, the revolution inscribed inner diameter (reduced tube diameter) of the sphere 6 is changed using the transfer surface 8a. I applied the method of increasing the size (Figure 3 (a)), but
For example, as shown in FIG. 3(b), a method of retracting the grooved plug 2b may also be used. However, the method of retracting the grooved plug 2b requires a movement stroke and length control is impaired. On the other hand, in the method of this embodiment, the retraction ffix + of the bushing 11 required by the method of this embodiment is, for example, when the slope of the transfer surface 8a is 4.
5 degrees, the movement stroke X1 of the pusher 11 corresponds to the change R1 in the inscribed radius of the ball 6, as shown in FIG. 3(C).
Since it is equal to (X + = Rt), the depth of the inner groove can be approximately the same (approximately 0.2 fins for air conditioners), so very quick and accurate control is possible. As a method of changing the diameter of the contracted tube, the tube may be contracted using a plurality of shafted rolls, and the diameter may be changed using a link mechanism. Further, as shown in FIG. 3 (dl), the surface of the pusher 11 in contact with the ball 6 may be made a slope. In this case, the reaction force received from the metal tube l of the ball 6 during tube contraction is transferred to the transfer surface 8a and the pusher 1.
It can be received on both sides of the slope of 1. pusher 11
It is necessary to rotate in synchronization with the revolution of the ball 6, and in order to keep the speed difference at the time of re-contact small, it is desirable to have a large moment of inertia and a small resistance of the bearing IO. The inner surface of the metal tube l is lubricated by sealing lubricating oil behind (upstream side) of the floating plug 2a inside the tube, and the outer surface is lubricated and cooled by the port 4 provided in the die holder 4.
This is done by supplying emulsion lubricating oil from a.

〔Effect of the invention〕

As explained above, according to the method and apparatus for manufacturing an internally grooved tube with an unprocessed portion of the present invention, the metal tube is placed at a position away from the groove processing means by a distance corresponding to the interval between the unprocessed portions of the metal tube. Since the unprocessed part detection means for detecting the unprocessed part is arranged and the operation of the interruption means is controlled based on the detection of the unprocessed part by the unprocessed part detection means, the length of the unprocessed part and the grooved part is It was possible to improve the accuracy of the width and pitch, and the yield and processing efficiency were also improved.

[Brief explanation of the drawing]

FIG. 1 and FIGS. 2(a) and 2(b) are explanatory diagrams showing one embodiment of the present invention. Figures 3 (a) to (di are explanatory diagrams showing tube shrinking means. Figures 4 (al, (bl) are explanatory diagrams showing conventional heat transfer tubes. Figure 5 (al to (C1) are explanatory diagrams showing conventional heat exchanger tubes. Explanatory diagram showing the pipes. Explanation of symbols 1 - Metal pipe 2 - Plug unit 2 a - - - 1 - Floating plug 2 b...
-1-------Grooved plug 2C3-1・-1-
--Drawing die 4--Dice holder 5---Moving device 7--Shaft 7b---Bearing 8-- One---
-Rotating head 9-1--Retainer 11--Button 13--Control section 15--1--Heat transfer tube 16 ----Shell 1'l-111---Heat transfer tube 17 18---IJ bend material 20---Fin 21--- ...-- Bell mouth to pipe part AI, A2'--'--Fluid a 6-... a 7cm-- a O 5a 6a 17a-1... 19-----... Rondo. - Stopper ball - - Frame rotation drive device transfer surface / Bearing - - Detection sensor - - Finishing die - - Projection tube plate groove hard solder

Claims (2)

[Claims] (1) In a method for manufacturing internally grooved tubes for heat exchangers such as air conditioners, refrigerators, boilers, etc., grooves are formed on the inner peripheral surface of the metal tube, and the formation of the grooves is interrupted to form non-grooved portions. After forming the groove and restarting the formation of the groove, when the non-grooved portion is detected at a subsequent position having a predetermined distance from the position where the groove is formed, the restarted formation of the groove is interrupted and another groove is formed. A method for manufacturing an internally grooved tube with an unprocessed portion, the method comprising forming a non-grooved portion. (2) A manufacturing device for internally grooved tubes for heat exchangers such as air conditioners, refrigerators, boilers, etc., comprising a pipe shrinking means for shrinking a metal pipe of a predetermined outer diameter, and a metal pipe in the pipe shrinking means. a groove processing means such as a grooved plug that forms a groove on the inner surface of the tube; and an interruption that forms an unprocessed portion without the groove by interrupting the operation of at least one of the tube contraction means and the groove processing means. means, an unprocessed part detection means provided at a position having a predetermined distance from the groove processing means, and detects the unprocessed part and outputs an unprocessed part detection signal, based on the unprocessed part detection signal, It has a control section that controls the interrupting operation of the interrupting means, and the control means operates the interrupting means when the tip of the unprocessed part is detected by the unprocessed part detection means, An internally grooved pipe with unfinished parts, characterized in that when the rear end is detected, the unfinished parts are formed at intervals equal to the predetermined distance by controlling the operation of the interruption means to stop. manufacturing equipment.