JP2010247181A - Method of manufacturing tube having groove on inside surface - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a tube having a groove on the inside surface, by which a tube having a double groove on the inside surface excellent in heat transfer performance is manufactured because defective shape is not generated, the breakage of the tube is not generated and the stable work of the tube having the double groove on the inside surface is performed. <P>SOLUTION: In the method of manufacturing the tube having the grooved inside surface in which a drawing stage where the tube stock is drawn to the drawing direction by a drawing means, a diameter reducing stage where the diameter of the tube stock is reduced, an auxiliary drawing stage where the drawing of the tube stock by the drawing means is assisted by an auxiliary drawing means and a grooving stage where a groove is formed on the inside surface of the tube stock by a grooving means are performed, and a load measuring stage where load which acts in the drawing direction is measured by a load measuring means and a controlling stage where the load is controlled so as to change periodically by controlling at least either of the drawing means and the auxiliary drawing means are also performed. In the controlling stage, the winding peripheral speed of at least either of the drawing means and the auxiliary drawing means is controlled. In the controlling stage, the pressing force to the tube stock of the auxiliary drawing means is controlled. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an internally grooved tube used as a heat transfer tube for a heat exchanger in a heat pump device such as an air conditioner, a water heater, a refrigerator, and floor heating, and a method for manufacturing the same.

  Heat transfer tubes used in heat exchangers of heat pump equipment such as air conditioners and water heaters are often used with grooved inner surfaces, for example, copper inner grooved tubes in order to improve heat exchange performance. .

  In recent years, in order to meet the demands for miniaturization and high efficiency of heat exchangers, the groove formed on the inner surface is deepened, the torsion angle (lead angle) of the groove is increased, the fin is sharpened, and the tube Internally grooved tubes with reduced wall thickness are manufactured.

  Furthermore, in order to improve the heat exchange performance of heat exchangers for heat pump equipment that uses chlorofluorocarbon refrigerant, an internally grooved tube (so-called cross-grooved tube) with discontinuous height fins formed on the inside surface was developed. (Patent Document 1). Furthermore, a manufacturing method for manufacturing the cross grooved tube by rolling is disclosed (Patent Documents 2 and 3).

JP-A-8-178574 JP-A-9-70612 JP-A-9-314264

  The inner grooved tube is grooved in such a way that the inner diameter of the tube immediately before grooving and the outer diameter of the grooved plug inserted in the tube are substantially equal, and the engagement between the tube and the grooved plug is improved. Applied. Similarly, in the manufacturing methods of Patent Documents 2 and 3, in the two grooving processes, the inner diameter of each of the immediately preceding tubes must be approximately equal to the outer diameter of the fluted plug.

  However, in the manufacturing methods of Patent Documents 2 and 3, it is difficult to control the inner diameter of the tube so as to match the outer diameter of the grooved plug. As a result, the meshing between the tube and the grooved plug deteriorates during processing, and a floating phenomenon occurs, so that a sufficient groove cannot be formed in some cases.

  Conversely, if the tip of the inner fin hits the grooved plug, it is processed while being crushed and expanded, increasing the resistance in the pulling direction and causing a problem of breakage.

  Therefore, the present invention is capable of processing a stable inner surface double-grooved tube without causing a defective shape or causing breakage of the tube as in the prior art, and an inner surface with excellent heat transfer performance. Provided is a method for producing an internally grooved tube capable of producing a double grooved tube.

The above-mentioned subject is achieved by the following means. That is, the present invention
(1) a drawing step of drawing the base tube in the drawing direction by a drawing means;
A diameter reducing step for reducing the diameter of the raw tube;
An auxiliary extraction step of assisting the extraction of the raw tube by the extraction means by the auxiliary extraction means;
A groove machining step of forming grooves on the inner surface of the raw tube by the groove machining means;
A method of manufacturing an internally grooved tube,
A load measuring step of measuring a load acting in the pulling direction by a load measuring means;
A control step of controlling at least one of the drawing means and the auxiliary drawing means based on the load measured by the load measuring means to control the load to change periodically is performed. Manufacturing method of internally grooved tube,
(2) A method for producing an internally grooved tube according to (1),
In the control step,
A method of manufacturing an internally grooved tube, characterized by controlling a winding peripheral speed of at least one of the drawing means and the auxiliary drawing means;
(3) A method for producing an internally grooved tube according to (1) or (2),
In the control step,
A method of manufacturing an internally grooved tube, wherein the pressing force of the raw tube of the auxiliary pulling means is controlled,
Is provided.

  According to the method for manufacturing an internally grooved tube of the present invention, it is possible to stably process an internally double-grooved tube without causing a defective shape or breaking the tube as in the prior art. It is possible to manufacture an internally double-grooved tube having excellent heat transfer performance.

It is sectional drawing which shows the manufacturing apparatus of the inner surface grooved pipe | tube of this embodiment. It is sectional drawing which shows a part which cut | disconnected the inner surface grooved pipe | tube of this embodiment diagonally with respect to the pipe axis. It is sectional drawing in the surface which passes along the pipe axis of the internally grooved pipe | tube of this embodiment. It is a graph which shows the control method of the processing load of the internally grooved pipe of this embodiment.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view of a manufacturing apparatus 12 for an internally grooved tube 11 according to this embodiment. The internally grooved tube 11 in the present embodiment can be manufactured using a manufacturing apparatus 12.

  The manufacturing apparatus 12 has a reduced diameter portion 13, an auxiliary drawing device 17, a grooving portion 14, and a finishing portion 15 in order from the upstream side to the downstream side in the drawing direction (drawing direction) (X direction in FIG. 1). The drawing device 16 is further provided on the downstream side, and the inner tube 11a is manufactured by continuously processing the raw tube 11a with these configurations.

  Specifically, the manufacturing apparatus 12 includes a diameter-reduced portion 13 that draws and reduces the diameter of the raw tube 11 a, a groove processed portion 14 that forms a large number of grooves on the inner surface of the raw tube 11 a, and a downstream side of the groove processed portion 14. A drawing device 16 that winds up the processed inner grooved tube 11 and an auxiliary drawing device 17 that draws the raw tube 11 a between the reduced diameter portion 13 and the groove processing portion 14 are configured. The drawing device 16 has a winding drum 36 and a motor M1.

  Further, the manufacturing device 12 is movable in the drawing direction X with respect to the fixed base 50, the reduced diameter portion 13, the auxiliary drawing device 17, the groove processing portion 14, the finishing processing portion 15, and a box 32 for housing them. A movable base 33 that supports the load base 35, a load cell 35 that detects a processing load P that acts in accordance with the movement of the movable base 33 relative to the fixed base 50, and an auxiliary pull-out based on the processing load P detected by the load cell 35. It is comprised with the control apparatus 45 which controls the apparatus 17. FIG.

Hereinafter, the structure of each part mentioned above is demonstrated.
The reduced diameter portion 13 constitutes a cylindrical die 22 for reducing the diameter of the passing raw tube 11a. The die 22 has a die hole 22a that opens toward the upstream side.

  Further, the reduced diameter portion 13 includes a floating plug 23 inside the raw tube 11a. The floating plug 23 is formed so that a part of the outer peripheral surface in the axial direction is formed in a truncated cone shape so as to be engageable with the die 22 through the raw tube 11a. Thereby, the floating plug 23 is rotatably engaged in the die 22 portion.

  In addition, the groove processing portion 14 includes a grooved plug 24 in which a plurality of spiral grooves are formed on the outer periphery inside the raw tube 11a.

  The grooved plug 24 and the floating plug 23 are rotatably connected to each other via a connecting rod 25. Further, the groove processing portion 14 includes a plurality of balls 26, and the plurality of balls 26 are disposed around the tube axis while being pressed against the tube 11a outside the tube 11a. .

  The grooved portion 14 is configured such that the grooved plug 24 abuts on the inner peripheral surface of the raw tube 11 a, the raw tube 11 a is pulled in the pulling direction while rotating around the axis, and pressed by the plurality of balls 26, thereby being pressed. A large number of parallel spiral grooves can be formed on the inner peripheral surface of the substrate. That is, the internally grooved tube 11 can be obtained by passing the groove processing portion 14.

  The finishing portion 15 is provided with a diameter adjusting die 27, and the inner grooved tube 11 passes through the die hole 27 a of the diameter adjusting die 27, for example, by pressing the ball 26 in the groove processing portion 14. Processing to smooth the diameter of the tube surface distortion is performed.

  The drawing device 16 includes a take-up drum 36 and a take-up motor M1, and winds around the take-up drum 36 while pulling the inner grooved tube 11 by the rotational drive of the motor M1.

  The auxiliary drawing device 17 assists the drawing by the drawing device 16 by drawing the raw tube 11a in the drawing direction between the reduced diameter portion 13 and the groove processing portion 14. That is, the grooving by the grooving section 14 becomes resistance when the raw tube 11a is pulled out, and the drawing load at the time of grooving increases, but the drawing load applied to the raw tube 11a by the auxiliary drawing device 17 is increased. Can be dispersed.

  The auxiliary pulling device 17 includes a pair of belts 42a and 42b arranged on the upper and lower sides or the left and right sides of the raw tube 11a. Each of the belts 42a and 42b is formed in a loop shape (endless shape), and is stretched around the pulley 43 so as to be rotatable by the rotational drive of the motor M2. The belts 42a and 42b are configured in a caterpillar type in which a plurality of pads 44 are continuously provided along the length direction on the outer peripheral surface.

  The pair of belts 42a and 42b in the auxiliary pulling device 17 is desired to have a pressing force of the raw tube 11a by the pad 44 of, for example, 0.3 MPa from the viewpoint of obtaining a sufficient pulling force and preventing deformation of the raw tube 11a. It is provided on each of the upper and lower sides with respect to the elementary tube 11a so as to be kept at the pressing force of.

  Although not shown, the pad 44 is formed with a pad groove in which the cut surface with respect to the connecting direction of the plurality of pads 44 has an arc shape at the contact portion with the outer surface of the base tube 11a after being reduced in diameter by the reduced diameter portion 13. is doing. In addition, you may provide the wiper for removing the oil film and foreign material adhering to the outer surface of the raw | natural pipe | tube 11a in the upstream of the said auxiliary extraction apparatus 17 (not shown).

  The movable table 33 is installed on the fixed table 50 via a plurality of wheels 33a so as to be movable in the drawing direction X or the opposite direction with respect to the fixed table 50. The processing unit 14, the finishing processing unit 15, and the auxiliary drawing device 17 are installed in a state where they are accommodated in a box 32.

  The load cell 35 is provided on the fixed base 50 at the downstream end portion in the drawing direction X of the movable table 33 so that the processing load P received from the movable table 33 according to the pulling force of the raw tube 11a can be detected.

  The control device 45 receives a load detection signal Sin obtained by converting the machining load P detected by the load cell 35 into an electrical signal, and outputs a control signal Sout for controlling the driving of the motor M2 of the auxiliary drawing device 17 in accordance with a control program.

  Furthermore, although not shown, the control device 45 temporarily stores an arithmetic unit (CPU) for executing signal analysis processing and arithmetic processing, a hard disk for storing necessary control programs, and the load detection signal Sin. In addition to this, an input unit such as a keyboard for inputting control parameters and a display unit such as a monitor can be appropriately provided.

  The inner grooved tube 11 in the present embodiment controls the speed of the motor M1 and the speed of the motor M2 to change the speed ratio, or controls the pressing force of the raw tube 11a by the pad 44 of the auxiliary drawing device 17. Thus, the processing load P can be controlled to manufacture the inner grooved tube 11 having a desired groove shape.

  As shown in FIGS. 2 and 3, the inner grooved tube 11 in which the height of the fins 1 is not constant, that is, a so-called cross grooved tube can be manufactured by the method of manufacturing the inner grooved tube 11 in this embodiment. .

  FIG. 2 is a cross-sectional view showing a part of the internally grooved tube of the present embodiment cut obliquely with respect to the tube axis. There are fins 1 and grooves 2 on the inner surface of the inner grooved tube 11. The difference in height between the top of the fin 1 and the groove 2 is referred to as the height of the fin 1. The fin 1 has the 1st fin 61 and the 2nd fin 71, and these are provided periodically periodically.

  FIG. 3 is a cross-sectional view of a surface passing through the tube axis of the internally grooved tube 11 of the present embodiment. The fins 1 and the grooves 2 are arranged with a twist angle β with respect to the central axis (vertical direction in FIG. 3) of the tube. The fin 1 is periodically provided with a first fin 61 and a second fin height 71 with a length L with respect to the central axis of the tube. The first fin 61 has a length L1 in the tube axis direction. The second fin 71 has a length L2 in the tube axis direction.

  A method for manufacturing the inner grooved tube 11 of the present embodiment will be described. First, as a preliminary test for manufacturing the inner surface grooved tube 11 of the present embodiment, using the above-described inner surface grooved tube manufacturing apparatus 12 for a tube of a desired material (a tube having a smooth inner surface before being grooved), The relationship between the machining load and the groove depth is measured in advance. That is, the machining loads P1 and P2 for obtaining the first fin height H1 and the second fin height H2 are calculated by changing the machining load P. The processing load P can be measured by the load cell 35.

  Next, the raw tube 11a is applied to the inner grooved tube manufacturing apparatus 12, and the inner grooved tube 11 is manufactured. The winding peripheral speed of the motor M1 and the winding peripheral speed of the motor M2 are set so that the processing load P becomes the processing loads P1 and P2 for obtaining the first fin height H1 and the second fin height H2. Or the pressing force of the raw tube 11a by the pad 44 of the auxiliary drawing device 17 is controlled.

  At this time, in order to periodically obtain the first fin height H1 and the second fin height H2, it is necessary to periodically change the speed ratio or the pressing force. FIG. 4 is a graph showing the relationship between the machining load and the fin height H of the internally grooved tube of this embodiment. The horizontal axis is the machining time t. The upper graph shows changes in the processing load P. The lower graph shows changes in the fin height H. That is, by controlling the machining load P as in the upper graph, the fin height H changes as in the lower graph. Here, by controlling the machining load P to be alternately P1 and P2, the depth of the groove 2 is alternately the height H1 and the height H2.

  When the control interval of the machining load P is a period S, a groove having a period L made of the first fin height H1 and the second fin height H2 is formed in the tube axis direction. At this time, if the winding circumferential speed of the motor M1 is V, the relationship is L = V × S. Therefore, L, V, and S should be set so as to obtain the inner grooved tube 11 having a desired shape.

In the above-described embodiment, the method of controlling the winding circumferential speed of the motor M1 and the winding circumferential speed of the motor M2 has been described. However, the motor M1, M2 is not limited to controlling the winding circumferential speed as a control parameter. The acceleration, torque, rotation angle, or a plurality of these may be controlled as control parameters.
Furthermore, although the height of the fin 1 was made into two types in embodiment mentioned above, you may form two or more types of several height.

  Moreover, although the example which attached the motor M2 to the drive of the said auxiliary | assistant extraction apparatus 17 is shown in FIG. 1, you may make it operate | move by attaching a motor to each right and left. In such a case, by using a motor that can follow the target operation control value such as a servo mechanism, the machining load P at the time of machining an internally grooved tube having a difficultly machined shape as in the present invention is easily obtained. This makes it possible to control in more detail and is effective in stabilizing the operation of the equipment.

In the correspondence between the above-described embodiment and the configuration of the present invention, the diameter-reduced portion 13 of this embodiment corresponds to the diameter-reducing means of the present invention.
The groove processing section 14 corresponds to the groove processing means,
The drawing device 16 corresponds to a drawing means,
The auxiliary extraction device 17 corresponds to auxiliary extraction means,
The movable part 33 corresponds to the movable means,
The load cell 35 corresponds to the load detection means,
The control device 45 corresponds to the control means,
The fixed base 50 corresponds to an installation part.
The present invention is not limited to the configuration of the embodiment described above, and many embodiments can be obtained.

DESCRIPTION OF SYMBOLS 11 ... Internal grooved pipe 12 ... Manufacturing apparatus 13 ... Diameter reduction part 14 ... Groove processing part 16 ... Extraction apparatus 17 ... Auxiliary extraction apparatus 33 ... Movable stand 35 ... Load cell 45 ... Control apparatus 50 ... Fixed stand 61 ... First fin 71: Second fin P: Processing load L: Length in the pipe axis direction H: Fin height H1: First fin height H2: Second fin height t: Processing time

Claims (3)

A drawing step of drawing the raw tube in the drawing direction by a drawing means;
A diameter reducing step for reducing the diameter of the raw tube;
An auxiliary extraction step of assisting the extraction of the raw tube by the extraction means by the auxiliary extraction means;
A groove machining step of forming grooves on the inner surface of the raw tube by the groove machining means;
A method of manufacturing an internally grooved tube,
A load measuring step of measuring a load acting in the pulling direction by a load measuring means;
A control step of controlling at least one of the drawing means and the auxiliary drawing means based on the load measured by the load measuring means to control the load to change periodically is performed. Manufacturing method of internally grooved tube. A method for producing an internally grooved tube according to claim 1,
In the control step,
A method for producing an internally grooved tube, wherein a winding peripheral speed of at least one of the drawing means and the auxiliary drawing means is controlled. A method for producing an internally grooved tube according to any one of claims 1 or 2,
In the control step,
A method for manufacturing an internally grooved pipe, wherein the pressing force of the raw pipe of the auxiliary pulling means is controlled.

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