JPH0671623B2 - Method and apparatus for manufacturing pipe with internal groove having unprocessed portion - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for producing an ungrooved inner surface grooved pipe for a heat exchanger such as an air conditioner, a refrigerator, a boiler, etc. TECHNICAL FIELD The present invention relates to a method and an apparatus for manufacturing an inner grooved tube with an unprocessed part, which is capable of manufacturing an unprocessed part with various pitches and lengths.

[Background technology]

Conventionally, bare tubes of copper or copper alloy, low fin tubes, etc. have been used as heat transfer tubes for heat exchangers.
In this type of heat transfer tube, for example, as shown in FIGS. 4 (a) and 4 (b), a plurality of heat transfer tubes 15 are housed in a shell 16, and a fluid A ₁ , which flows on the inner and outer surfaces of the heat transfer tube 15. is heat exchanged between A _2,
It is industrially used in large quantities as a so-called shell and tube heat exchanger. In such a heat exchanger, when the heat transfer tube 15 is attached to the tube plate 16a integrated with the shell 16, the heat transfer tube 15 is inserted into the tube plate 16a as shown in FIG. The heat pipe 15 is generally fixed by applying a strong pipe expanding force from the inside of the heat pipe 15 with a small diameter roll or the like to engage the protrusion 15a with the recess 16b. This is technically easy when the inner surface of the heat transfer tube 15 is smooth.

On the other hand, as such a heat transfer tube for a shell-and-tube heat exchanger, an inner grooved tube having high heat transfer performance has recently been widely used even for a fluid such as CFCs that changes in phase. In this case as well, the tube is mounted to the tube 16a in the same way, but the tube with inner surface groove also has an inner surface groove in the tube mounting part, so when expanding the tube (in most cases, the so-called roller tube expansion method is used). The inner surface protrusions on both sides of the groove are stretched and folded, and flakes are generated, which may adversely affect the equipment constituting the refrigeration cycle.

In addition, the heat exchangers for room air conditioners that are currently being mass-produced are mainly fin-and-tube type heat exchangers as shown in FIGS. The inner grooved tube has fine spiral grooves 17a on the inner surface for improving thermal performance. The heat transfer tube 17 is bent into a hairpin shape as shown by B and C, and its end having a bell mouth expansion part 21 is connected to another heat transfer tube 17 adjacent to another via a U bend material 18 and a brazing filler metal 19. And is assembled with a heat exchange fin 20 that exchanges heat with the air. However, in general, this type of heat transfer tube 17 is provided with the groove 17a over the entire length, so that, for example, as shown in FIG.
When processing the bell mouth expanded portion 21 for inserting the bend material 18, cracks are likely to occur due to the notch effect of the inner surface groove 17a, and when brazing is performed by heating, the capillary force of the groove 17a is also added to the brazing material 19 There is a drawback that it becomes easy to flow into the pipe along the groove 17a, and a large amount of brazing material is required for reliable brazing. Furthermore, as shown in Fig. 5 (c), the outer wall 17A of the hairpin bent portion is thinned by the stretching of the tube wall, so the bottom wall thickness cannot be made thinner than a certain extent. Since the wall thickness must be increased, there is also the inconvenience that this causes a cost increase.

As a solution to this, a proposal has been made of a heat transfer tube having an unprocessed part without grooves of constant pitch in a part corresponding to the end and the bent part of the above-mentioned hairpin (inner grooved tube with unprocessed part), It has already been produced on an experimental scale (for example, JP-A-63-80915). Examples of the manufacturing apparatus for the inner grooved pipe with an unprocessed portion include, for example, a shrinking means for shrinking a metal tube from the outside and / or a groove working means for processing a groove from the inside of a reduced metal tube. There is one in which an ungrooved inner surface grooved pipe is continuously manufactured by providing an interrupting means for interrupting the operation of (1) at a predetermined timing. In mass production of such a heat transfer tube, a long coil tube is inevitably used as a raw tube, and after continuously performing internal groove processing, it is cut directly into a straight material on the same line, or once a coil strip is formed. After winding it up, it is straightened back on another line and cut into pieces.

[Problems to be Solved by the Invention]

However, according to the conventional apparatus for manufacturing an ungrooved inner surface grooved pipe, the operation of the contracting means or the groove processing means is interrupted at a predetermined timing for manufacturing, so that sufficient accuracy is not always obtained. However, when cutting a long material into a certain length, for example, even a slight pitch error is accumulated, which leads to a deviation of the cutting position, resulting in the inconvenience that the yield and the processing efficiency decrease. To do.

Therefore, it is an object of the present invention to provide a method and an apparatus for manufacturing an ungrooved inner surface grooved pipe in which the accuracy of the length and pitch of the unmachined portion is improved.

[Means for Solving the Problems]

In order to achieve the object described above, the present invention interrupts the formation of a groove to form an unprocessed portion, and then resumes the formation of the groove. Provided is a method for manufacturing an inner grooved pipe with an unmachined portion, which interrupts the formation of the groove again when the processed portion is detected.

Further, in order to achieve the above-mentioned object, unprocessed part detection means for detecting an unprocessed part of the metal pipe is arranged at a position separated from the groove processing means by a distance corresponding to an interval of the unprocessed part of the metal pipe, Provided is an apparatus for manufacturing an inner grooved pipe with a non-machined portion, wherein the control means controls the operation of the interrupting means based on the detection of the non-machined portion by the machine part detecting means.

That is, the manufacturing apparatus for an ungrooved inner surface grooved pipe of the present invention arranges the unprocessed portion detection means at a position separated from the groove processing means by a distance corresponding to the unprocessed portion interval of the metal pipe, When the unprocessed part is detected by the part detecting means, the interrupting means is operated to generate the next unprocessed part so that the unprocessed part is always formed at a constant pitch. As a result, the grooved portion and the unmachined portion having a constant length are always formed. The manufacturing apparatus of the inner grooved pipe with the unprocessed portion of the present invention includes the following means.

(1) Condensing tube means A metal tube having a predetermined outer diameter is contracted. For example, a configuration is adopted in which a plurality of rolls or spheres are rotated in a planetary shape and are contracted.

(2) Groove processing means A groove is formed on the inner surface of the metal pipe in the contracting pipe means. For example,
A groove is formed by inserting a floating grooved plug into a metal tube in a freely rotatable state and contracting it by the contracting means.

(3) Discontinuation means The operation of both or one of the shrinking tube means and the groove processing means is interrupted to form an unprocessed portion. Specifically, increase the contracted tube diameter of the contracted tube means (for example, the diameter of the inscribed circle of a roll or a sphere that rotates around the metal tube in a planetary manner) to pass through the metal tube without performing the tube contraction work. Alternatively, the groove processing means such as the grooved plug is moved to move away from the contracting tube means to interrupt the groove processing. Therefore, both or one of them is axially displaced by a motor or the like.

(4) Unmachined part detection means The groove machining means such as a grooved plug is arranged on the same axis as the metal pipe in a direction corresponding to the distance between the unmachined parts in the traveling direction of the metal pipe, and the interruption means interrupts the groove machining. The unprocessed part formed by is detected and an unprocessed part detection signal is output.

(5) Control means The interruption means is controlled based on the unprocessed portion detection signal. Specifically, the interrupting means is operated by the unprocessed portion detection signal that detects the tip of the unprocessed portion to form the unprocessed portion, and the interrupting means is detected by the unprocessed portion detection signal that detects the end of the unprocessed portion. And the formation of the grooved portion is started.

〔Example〕

Hereinafter, a method for manufacturing an inner surface grooved tube with an unprocessed portion and an apparatus therefor according to the present invention will be described in detail.

FIG. 1 shows an embodiment of the present invention, which is a groove processing device provided with a contracting means, a groove processing means and an interrupting means,
A detection sensor 12 as an unprocessed portion detection means, a control portion 13 for controlling the moving device 5 which is an interruption means of the groove processing device based on a signal from the detection sensor 12, and an outer diameter of the inner grooved pipe. It consists of 14 finishing dies.

Then, the plurality of spheres 6 that rotate in a planetary shape, which are the contraction means of the groove processing device, are attached to the shaft 7 that is rotated by the rotation drive device 7c that is rotationally fixed to the mount 7a through the bearing 7b. It is housed in the rotary head 8. The plurality of balls 6 are kept from contacting each other by a retainer 9 arranged therebetween. The rotary head 8 has a rolling surface 8a whose inner diameter gradually decreases toward the rear (upstream side), and the plurality of balls 6 are pressed by a pusher 11 rotatably attached to the die holder 4 via bearings 10. Then, the rolling surface 8a is brought into contact with the rolling surface 8a, and the inscribed circle diameter thereof has a predetermined dimension.

The grooved plug 2b, which is groove processing means and has a plurality of fine grooves formed on the outer periphery, is rotatably attached to the floating plug 2a via the rod 2c to form the plug unit 2. This plug unit 2 has a drawing die 3 with a floating plug 2a attached to a die holder 4.
By engaging with the grooved plug 2b, the grooved plug 2b can be held at a predetermined position (position where a plurality of balls 6 are arranged).

The die holder 4 is attached to a moving device 5 for axial movement, and is moved in the axial direction by the operation of the moving device 5 so that the grooved plug 2b and the ball 6 can be moved to a predetermined position. There is. In this case, the fine adjustment of the axial position can be performed by the stopper 4a. Therefore, while moving the metal tube 1 from the right side to the left side in the drawing with the plug unit 2 inserted in the metal tube 1, the moving device 5 is operated to move the grooved plug 2b and the ball 6 to predetermined positions. Thus, the metal tube 1 is contracted by a plurality of spheres 6 that rotate like a planet at the position of the grooved plug 2b, and the grooved plaque is
It is pressed against 2b and a groove is continuously formed on the inner surface.

On the other hand, the detection sensor 12 is composed of, for example, an eddy current type detection coil or the like, and is capable of detecting a change in the outer diameter of the passing metal tube 1 and outputting a signal thereof to be input to the control unit 13. Therefore, the detection sensor 12 has a certain distance l ₀ (from the position where the groove is formed by the grooved plug 2b and the ball 6 on the axis connecting the groove processing device and the finishing die 14 to the grooved portion). Corresponding) is located at a position away only. Therefore,
The unprocessed part 1a exists in the passing metal tube 1, and the detection sensor
If 12 detects the front end of the unprocessed portion 1a, the control unit 13 is operated by the detection signal to operate the moving device 5 to retract the die holder 4, and if the rear end of the unprocessed portion 1a is detected, Based on the detection signal, the controller 13 and the moving device 5 can be used to move the die holder 4 forward and return it to the original position.

In order to manufacture an ungrooved inner surface grooved tube with the apparatus having the above-described structure, the moving device 5 is operated to retract the grooved plug 2a from a predetermined position, and the metal tube 1 is moved in that state. At the same time, after rotating the rotary head 8, the moving device 5 is operated to move the die holder 4 forward to a predetermined position. As a result, the grooved plug 2b moves forward to a predetermined position, and the balls 6 are moved forward by the pusher 11 while the rolling surface 8a reduces the diameter of the inscribed circle. The tube 1 is contracted, and the inner surface of the tube 1 is continuously grooved.

Then, when the moving device 5 is operated during this inner surface groove machining to temporarily retract the die holder 4 (in the direction of the solid line arrow) and return it (in the direction of the dotted line arrow), the floating plug 2a is removed as the die holder 4 retracts. Then, the grooved plug 2b is retracted, and the pusher 11 is used to reduce the pressing force on the plurality of balls 6 to increase the inscribed circle diameter of the plurality of balls 6, so that the metal pipe 1 passing therethrough is temporarily As a result, the restriction by the grooved plug 2b and the plurality of balls 6 is released and the inner surface groove machining is interrupted. As shown in FIG. 2 (a), the outer diameter is slightly larger and the inner surface has a predetermined length with no groove. The unprocessed portion 1a having L ₁ is formed.

When the inner surface groove processing progresses and the unprocessed portion 1a reaches the position of the detection sensor 12, the detection sensor 12 detects the tip of the unprocessed portion 1a. Operates to retract the die holder 4.
As a result, similarly to the above, the constraint by the grooved plug 2b and the plurality of balls 6 is released, and the inner surface groove machining for the metal pipe 1 passing therethrough is interrupted. Then, when the detection sensor 12 detects the rear end of the unprocessed portion 1a, the control signal is detected by the detection signal.
13. The moving device 5 is used to move the die holder 4 forward and return it, and the inner surface groove machining by the grooved plug 2b and the plurality of balls 6 is restarted. Therefore, by repeating this operation, it is possible to obtain the inner grooved pipe in which the unprocessed portion 1a having the predetermined pitch (distance) l ₀ and the predetermined length L ₁ is formed, and further, l ₀ and L ₁
There is no fear of error accumulating.

The metal tube 1 having the inner surface grooved therein is then drawn out through the finishing die 14 so that the unprocessed portion 1a is contracted, and the tube has the same outer diameter as shown in FIG. 2 (b). At this time, the length L ₂ of the unprocessed portion 1a becomes slightly longer than the initial length L _{1 due} to reduction (L ₂ > L ₁ ). Further, while the unprocessed portion 1a is being pulled out by the finishing die 14, the conveying speed of the material before entering the finishing die 14 becomes slightly slower, so that the finishing die 14
If the inner surface groove processing is continued when the drawing process is continued, there may occur inconveniences such as an unnecessary ring mark appearing on the surface or the inner surface groove is disturbed. Therefore, when continuing the drawing process with the finishing die 14,
It is desirable to interrupt the inner surface groove machining while the 1a is being drawn by the finishing die 14. In that sense, the control method described above is an appropriate means.

The distance between the detection sensor 12 and the finishing die 14
_1, the detection sensor 12, it becomes necessary to the absorption level allowing the time lag of the electro mechanical system between the control unit 13 and the mobile device 5. That is, when the speed of the metal tube 1 when it is drawn out by the finishing die 14 is V, the above-mentioned time lag t and the distance l ₁ are l ₁ = V / t. Furthermore, if the delay time T is positively set, then l ₁ = V / t + V / T can be satisfied. In this embodiment, the rolling surface 8a is used to leave the unprocessed portion 1a, and the diameter of the circle inscribed on the revolution of the ball 6 (the diameter of the reduced pipe)
The method (FIG. 3 (a)) for increasing the value is applied. However, for example, as shown in FIG. 3 (b), a method of retracting only the grooved plug 2b may be used. However, the method of retracting only the grooved plug 2b is to move the travel stroke X ₂ by several mm.
In the case where the line speed is high, for example, when machining the inner surface of a small-diameter thin-walled copper pipe for an air conditioner, the control of the pitch and the length is hindered. On the other hand, in the method of this embodiment, the amount of retraction of the pusher 11 required
If X ₁ is, for example, 45 ° of inclination of the rolling surface 8 a, as shown in FIG. 3 (c), the movement stroke X ₁ of the pusher 11
Becomes equal to the change of the inscribed radius of the sphere R ₁ (X ₁ = R ₁ ).
Since the depth is about the same as the inner groove depth (about 0.2 mm for air conditioners), quick and accurate control is possible. As a method for changing the diameter of the contracted pipe, the contracted pipe may be changed by using a plurality of axial rolls and a link mechanism. Further, as shown in FIG. 3 (d), the surface of the pusher 11 in contact with the ball 6 may be an inclined surface. In this case, the ball 6
The reaction force received from the metal tube 1 of the rolling surface 8a and the pusher
Can be received on both sides of 11 slopes. The pusher 11 needs 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, the moment of inertia is large,
Moreover, it is desirable to reduce the resistance of the bearing 10. Lubrication of the inner surface of the metal tube 1 is performed by sealing the lubricating oil in the rear (upstream side) of the floating plug 2a in the tube. Lubrication and cooling of the outer surface are performed by supplying emulsion lubricating oil from the port 4b provided in the die holder 4. .

〔The invention's effect〕

As described above, according to the manufacturing method of the ungrooved inner surface grooved pipe of the present invention and the apparatus thereof, the metal pipe of the metal pipe is located at a position separated from the groove machining means by a distance corresponding to the unmachined portion of the metal pipe. 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 and pitch of the unprocessed part can be controlled. The precision can be improved, and the yield and the processing efficiency can be improved.

[Brief description of drawings]

1 and 2 (a) and (b) are explanatory views showing an embodiment of the present invention. FIGS. 3 (a) to 3 (d) are explanatory views showing a contracting means. 4 (a) and 4 (b) are explanatory views showing a conventional heat transfer tube. FIGS. 5A to 5C are explanatory views showing a conventional inner grooved tube. Explanation of code 1 …… Metal tube 2 …… Plug unit 2a …… Floating plug 2b …… Groove plug, 2c …… Rod 3 …… Drawing die 4 …… Die holder, 4a …… Stopper 5 …… Movement device, 6 ...... Ball 7 ...... Shaft, 7a ...... Stand 7b ...... Bearing, 7c ...... Rotation drive device 8 ...... Rotating head, 8a ...... Rolling surface 9 ...... Retainer, 10 ...... Bearing 11 ...... Pusher, 12 ...... Detection sensor 13 ...... Control section, 14 ...... Finishing die 15 ...... Heat transfer tube, 15a …… Projection section 16 …… Shell, 16a …… Tube sheet 17 …… Heat transfer tube 17, 17a …… Groove 18 …… U vent material, 19 …… Hard solder 20 …… Fin 21 …… Bell mouth expansion part A ₁ , A ₂ …… Fluid

Claims (2)

[Claims] 1. A method of manufacturing an inner grooved tube for a heat exchanger such as an air conditioner, a refrigerator, a boiler, etc., wherein a groove is formed at a predetermined position on an inner peripheral surface of a moving metal tube, and the groove is formed. And a method for forming an unprocessed part by disposing the unprocessed part, wherein the unprocessed part detecting means is arranged at a position at a rear stage having a predetermined distance from the position where the groove is formed, and the unprocessed part detecting means precedes. A method for manufacturing an inner grooved pipe with an unprocessed part, characterized in that, when an unprocessed part is detected, the formation of the groove is interrupted to form another unprocessed part. 2. In a manufacturing apparatus for an inner grooved pipe for a heat exchanger such as an air conditioner, a refrigerator, a boiler, etc., a contracting means for contracting a metal tube having a predetermined outer diameter, and the contracting means. At least one of groove processing means such as a grooved plug for forming a groove on the inner surface of a metal tube, and the contracting tube means and the groove processing means.
Interruption means for forming an unprocessed portion having no groove by interrupting the operation of the two means, and a position provided at a predetermined distance from the groove processing means, detecting the unprocessed portion and detecting the unprocessed portion A non-machined portion detection unit that outputs a signal, and a control unit that controls the suspending operation of the suspending unit based on the non-machined portion detection signal, wherein the control unit detects the tip of the non-machined portion. When the rear end of the unprocessed part is detected, the uninterrupted part is controlled to stop the operation of the uninterruptible part when the rear end of the unprocessed part is detected. An apparatus for manufacturing an inner grooved tube with an unprocessed portion, which is characterized by being formed.