JPH0199712A - Apparatus for manufacturing internally grooved pipe - Google Patents

Abstract

PURPOSE:To improve productivity and to simplify the installation by providing preceding and succeeding rotary heads having plural rolling rolls respectively and by rotating reversely in synchronization with each other, and by interposing a grooving plug in the metallic pipe to perform the rolling. CONSTITUTION:The preceding rotary head 2 having plural rolling rolls 22 is provided and the succeeding rotary head 4 equipped with the plural rolling rolls 42 is disposed. When a driving shaft 30 is rotatively driven, the preceding and succeeding rotary heads 2, 4 are rotated synchronously and reversely each other through a pinion gear 30a and rotated around the metallic pipe 5. At this time, the rolling roll 22 performs the grooving by cooperating with the grooving plug 51, while reducing the diameter of the metallic pipe 5. The rolling roll 42 crashes the top of the grooved projecting part cooperating with a smoothing plug 52, while eliminating the tortional force of the roll 22. Because the drawing and rolling are performed at one time, the productivity is improved and the installation is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an apparatus for manufacturing internally grooved tubes used for heat exchanger tubes such as heat exchangers.

(Prior art and its problems) A heat transfer tube for an air conditioner that exchanges heat by evaporating or condensing a refrigerant such as Freon has a large number of protrusions, grooves, etc. formed axially or spirally on the inner circumferential wall of the tube. Internally grooved tubes with improved thermal properties are known. Various methods have been proposed for manufacturing these inner-grooved tubes, but the method shown in FIG. 8 is one that involves rolling.
This is known from Japanese Utility Model Publication No. 62-22246. In this method, two sets of tube shrinking heads C and C each having a plurality of planetary rollers b that press the outer periphery of a metal tube a are arranged in series facing each other, and are rotatably held at the tip of a mandrel d. Insert the long grooved plug e into the inside of the metal tube a at the portion facing each planetary roll b of the two sets of tube shrinking heads C, C, and while rotating each tube shrinking head C in opposite directions, Multiple grooves or protrusions are formed on the inner surface of the tube, and by rotating the tube shrinking heads c and c in opposite directions, it cancels out the tearing force of the tube during rolling and enables deeper grooves to be formed. ing.

However, if two sets of tube shrinking heads c and c are arranged and driven individually, the configuration becomes complicated and large-scale, equipment costs increase, and the processing cost of the internally grooved tube increases. Also, using two sets of constricting heads C with one grooved plug e is
As mentioned above, although it has the advantage of being able to increase the depth of the groove that can be machined by grooving, the 21Jfi shrinking head C
In addition, there is a problem that centering is difficult, and the contact area between the grooved pipe material and the grooved plug e becomes large, increasing frictional resistance when drawing the pipe, making it impossible to increase the processing speed.

The present invention has been made to solve these problems, and is capable of reducing the tearing force of the pipe during rolling processing, increasing the processing speed of internal grooves, and, in addition, having a simple configuration and requiring no large-scale equipment. The purpose of the present invention is to provide an apparatus for manufacturing internally grooved tubes, which is suitable for heat exchanger tubes for evaporating a heat medium, and which therefore requires low manufacturing equipment costs and does not cause an increase in tube processing costs. do.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the internally grooved tube manufacturing apparatus of the present invention includes a drawing die for drawing out a metal tube, and a drawing die that rotates planetarily around the outer periphery of the metal tube to be drawn. A first rotating head that has a plurality of rolling rolls that press the outer circumferential wall of the metal tube, and a second rotating head that has at least a plurality of rolling rolls that rotate planetarily around the outer periphery of the metal tube to be drawn and press the outer circumferential wall of the metal tube. They are disposed in series on the same axis in the drawing direction and incorporated into the housing, and a head rotation drive device synchronizes the rotation of the front and rear rotary heads, and rotates them together in opposite directions, and the front and rear rotary heads are rotated integrally in opposite directions. A floating plug is inserted into the metal tube facing the drawing die of the rotary head, and a floating plug is rotatably disposed in the metal tube facing the rolling roll of the preceding stage rotary head at the rear of the floating plug, and the metal tube to be drawn is inserted. a grooved plug forming a large number of protrusions on the inner circumferential wall surface; and a smoothing plug disposed in a metal tube facing the rolling roll of the rear rotary head to crush the tops of the protrusions formed by the grooved plug. It is characterized in that the plug and the plug are sequentially connected via a rond.

(Function) Since the front rotary head and the rear rotary head are built into the same housing and arranged in series and coaxially in the metal tube drawing direction, the drawing dies, rolling rolls, and rear rotary head of the front rotary head are At least the rolling rolls of the head are less likely to be misaligned with each other.

Since the front rotary head and the rear rotary head are synchronized and rotated together in opposite directions by the head rotation drive device, the torsional forces generated during the rolling process of the metal tube are canceled out, and the above-mentioned misalignment is avoided. Coupled with the fact that this is unlikely to occur, it is possible to rotate each head at high speed. Further, by sequentially connecting a grooved plug and a smooth plug to the rear part of the floating plug via a rond, a process of forming a large number of protrusions on the inner circumferential surface of the metal pipe in one drawing and rolling process; A step of crushing the top of this protrusion is performed at the same time.

(Example) An example of the present invention will be described in detail below based on the drawings.

FIG. 1 shows a schematic configuration of an apparatus for manufacturing an internally grooved pipe according to the present invention, in which two sets of rotating rads 2 and 4 are incorporated inside a split casing 1, and these rotating rads 2 and 4 are installed inside a split casing 1. 4
are synchronously rotated together in opposite directions by the head rotation drive device 3, and while drawing the raw tube (metal tube) 5, grooves are formed on the inner circumferential wall thereof by rolling.

More specifically, the rotary heads 2.4 are arranged coaxially and in series in the drawing direction of the metal tube 5, and are configured in a substantially symmetrical shape with respect to the axis of a drive shaft 30, which will be described later. That is, the rotating rad 2 in the previous stage is a drawing die (drawing die) 21
, three rolling rolls 22, and an annular helad body 20 that supports these. head body 20
at a predetermined depth in the axial direction from the front side surface (the side surface on the insertion side of the metal tube 5) 20a toward the rear side surface 20d, and
Grooves 200 with a rectangular cross section (see Fig. 2) are bored at three equal positions in the circumferential direction, and the groove depth becomes shallower as the groove bottom 20b approaches the rear surface 20d in the radial direction. A roll holder 22a that pivotally supports the rolling roll 22 and a divided block 23 that supports a bearing 10 (to be described later) are fitted in order into each groove 20c, and these roll holders 22a and divided block 23 are attached to the front side of the helad body 20. A ring-shaped retainer 24 screwed onto 20a prevents it from falling off.

The kJ roll 22 is rotatably supported by a roll holder 22a via a spindle and a bearing, and the center of each rolling roll 22 is a metal tube 5 on which a protrusion, which will be described later, is rolled by the rolling roll 22. The centers are adjusted so that they are on the same circumference with the center on the central axis of. Each rolling roll 22
The centering is adjusted by interposing a shim or the like between the groove 20C and each side wall of the roll holder 22a, and moving the roll holder 22a back and forth in the axial direction of the metal tube 5 with the inclined groove bottom 20b.

The drawing die 21 has a bearing 10 and the aforementioned split block 23 in front of the rolling roll 22 (on the insertion side of the metal tube 5).
is supported by the head body 20 in alignment with the centered rolling roll 22, and is fixed so as not to rotate as the metal tube 5 passes.

A helical face gear 20e that meshes with pinyon gears 30a and 31a, which will be described later, is formed on the periphery of the rear side surface 20d of the head body 20. And head body 20
The outer peripheral surface of the housing 1 is connected to the housing 1 through bearings 12 and 12.
is rotatably supported on the cylindrical inner circumferential surface of the front side surface 2Oa.
The side is supported with a thrust bearing 13 interposed between the end plate la of the housing 1 and the retainer 24.

The rear rotary head 4 has a drawing die (drawing die) 41
It is composed of three rolling rolls 42 and an annular helad body 40 that supports them, and each of these components, except for the roll shape of the rolling roll 42 and the die shape of the drawing die 41, It is disposed at a symmetrical position with respect to the central axis of a drive shaft 30, which will be described later, with corresponding components of the helad 2, and has a symmetrical shape.

The head body 40 has a groove bottom 40b with a predetermined depth in the axial direction from the rear side surface (the side surface on the drawing side of the metal tube 5) 40a toward the front side surface (the side surface of the two examples of the rotating heads in the previous stage) 40d. Grooves 40c each having a rectangular cross-section and sloping so that the groove depth becomes shallower toward the front side surface 40d in the radial direction are bored at three equal positions in the circumferential direction, and a rolling roll 42 is formed in each of these grooves 40c. A roll holder 42a that pivots and a split block 43 that supports a bearing 15 (described later) are fitted in order, and these roll holders 42a and split block 43 are a ring-shaped retainer that is screwed onto the rear side 40a of the helad body 40. 44 prevents it from falling off.

The rolling rolls 42 are rotatably supported by a roll holder 42a via a support shaft and a bearing, and the centers of each rolling roll 42 are on the same circumference centered on the central axis of the metal tube 5. The centering is adjusted so that each rolling roll 42
The centering of the drawing die 41 is adjusted by interposing a shim or the like between the groove 40c and each side wall of the roll holder 42a, and moving the roll holder 42a back and forth in the axial direction of the metal tube 5 with the inclined groove bottom 40b. A bearing 15 and the aforementioned split block 4 are placed behind the rolling roll 42 (on the drawing side of the metal tube 5).
3, it is supported by the head body 40 in alignment with the centered rolling roll 42, and is fixed so as not to rotate when the metal tube 5 passes.

A helical face gear 40e that meshes with binon gears 30a and 31a, which will be described later, is formed on the periphery of the front side surface 40d of the head body 40. And head body 40
The outer peripheral surface of the housing 1 supports the head body 20 of the rotating RAD 2 in the previous stage via bearings 16.16.
is rotatably supported on the same cylindrical inner circumferential surface of the rear side surface 4.
The Oa side is supported with a thrust bearing 17 interposed between the end plate 1b of the housing 1 and the retainer 44.

In this way, the front rotating head 2 and the rear rotating head 4 are drawn and rolled with the rear side 20d where the face gear 20e is formed and the front side 40d where the face gear 40e is formed facing each other. The metal tubes 5 are arranged in series on the central axis of the metal tube 5.

The head rotation drive device 3 consists of a drive shaft 30 and an idler shaft 31, which are rotatably supported on the hanging 1 so as to face each other, and the shaft end side of the drive shaft 30 extending outward from the housing 1 is It is connected to a drive motor (not shown) via a power transmission means such as a belt, and the above-mentioned pinion gear 30a is fixed to the inner shaft end of the hanging 1. As mentioned above, this pinion gear 30a is formed on the helad bodies 20 and 40. , face gears 20e facing each other.

It meshes with 40e. On the other hand, the above-mentioned pinion gear (idler gear) 31a is fixed to the inner shaft end of the hanging 1 of the idler shaft 31, and as mentioned above, this pinion gear 3
1a also meshes with face gears 20e and 40e formed on the head bodies 20 and 40.

A floating plug 50 is inserted into the metal tube 5 to be drawn and rolled at a position opposite to the drawing die 21 of the pre-stage rotary head 2, and a rod (connection) extending in the drawing direction is inserted at the rear end of the floating plug 50. A cylindrical nib lug 51 having a predetermined outer diameter is rotatably attached to the rod 53 at a position opposite to the rolling roll 22 of the front-stage rotary head 2 . Rolling roll 42
A cylindrical smooth plug 52 having a slightly smaller diameter than the nib plug 51 is fixed at a position opposite to the nib plug 51 .

Incidentally, grooves for forming a number of protrusions described later on the inner circumferential wall of the metal tube 5 are cut on the outer circumferential surface of the nib lug 51.

In addition, the reference numeral 8 in FIG. 1 is a lubricating oil supply device that lubricates the outer peripheral surface of the metal tube 5, especially the rolling surfaces of the rolling rolls 22 and 42. A large number of nozzles are installed toward the rolling surfaces of the rolling rolls 22 and 42, and lubricating oil is sprayed and supplied from the nozzles.

Next, the operation of the manufacturing apparatus configured as described above will be explained.

When the drive shaft 30 is rotationally driven by the drive motor,
The front and rear rotary heads 2.4 meshing with the pinion gear 30a are driven to rotate around the metal tube 5 in synchronization with each other in opposite directions. The rolling rolls 22 and 42 are used to roll the metal tube 5 during the rolling process in which the metal tube 5 passes through the rolling rolls 22 and 42.
The planets rotate in opposite directions while pressing against the outer circumferential walls of the two planets.

This rolling roll 22 serves as a tool for grooving the inner circumferential wall surface of the metal tube 5, and the roll surface is formed into an arc-shaped cross section (R-shape) or a tapered R-shape as shown in FIG. This reduces the rolling force when grooving is performed while reducing the diameter of the metal tube 5, and facilitates the flow of material into the nib lug 51, which will be described later. On the other hand, although the roll surface of the rolling roll 42 has eight chamfered corners as shown in FIG. The diameter of the metal tube 5 is reduced while crushing the top of the protrusion formed by the rolling roll 22 as will be described later.
Finish the outer surface smooth.

At this time, the rolling roll 42 rotates in the opposite direction to the rolling roll 22, thereby generating a torsional force in the opposite direction to the torsional force generated during the grooving process by the rolling roll 22, and these tearing forces cancel each other out. This relieves the torsional stress of the metal tube 5 and prevents the metal tube 5 from breaking. Further, the rolling roll 42 having a flat shape prevents the metal tube 5 from wobbling.

Furthermore, the pressing force on the tube material by the rolling rolls 42 is relatively small, the above-mentioned torsional force is alleviated, and the front rotation gear 2 and the rear rotation head 4 are configured symmetrically with respect to the axis of the drive shaft 30. Together with this, the drawing speed can be significantly increased compared to conventional devices.

To perform groove processing, first, lubricant oil is injected into the metal tube 5 in advance, and the floating plug 50, the nib plug 51, and the smooth plug 52, which are integrally connected by a rod 53, are inserted into the metal tube 5. After charging, cut the end of the metal tube 5 to the required length (
For example, about 500 mm), the pipe end is passed through the drawing die 21, the rolling rolls 22, 42, and the drawing die 41.
are sequentially communicated, and drawing is started after winding by a winding drum (not shown). Simultaneously with the start of this drawing, the aforementioned drive motor is activated to rotate the drive shaft 30 at high speed, thereby rotating the rads 2 and 4 in two rotations in opposite directions.

The floating plug 50 inserted into the metal tube 5 is moved to a predetermined position facing the drawing die 21 and positioned, and accordingly, the floating plug 50 is moved to a predetermined position facing the drawing die 21 and the drawing is about to start. It will be positioned at a predetermined position facing each other. (Thus, after the diameter of the metal pipe 5 is reduced by the floating plug 50 and the drawing die 21, the inner wall of the pipe is reduced by the full nib plug 51 and the rolling roll 22 as shown by the solid line in FIG. 5 and the broken line in FIG. A large number of protrusions 5a are formed in the groove.The tops of the protrusions 5a are crushed by the smooth plug 52 and the rolling roll 42 as shown by solid lines in FIG. At the same time, the irregularities on the outer surface of the tube caused by the groove processing using the nib lug 51 and the rolling roll 22 are finished to a smooth state.In this way, by forming voids in the groove, the shape is suitable for boiling and evaporating the refrigerant. is realized.

The drawing die 41 is connected to the drawing die 21 and the rolling roll 22.4.
2, and by slightly reducing the diameter of the metal tube 5, the outer surface is finished smooth, and furthermore, the lubricating oil supplied by the lubricating oil supply device 8 is prevented from leaking outside the device. At the same time, the pipe deflection of the metal pipe 5 being drawn and rolled is also prevented.

The shape and pitch of the protrusion 5a to be grooved in the above embodiment,
The inclination with respect to the tube axis, etc. can be changed in various ways by forming grooves or protrusions carved into the outer surface of the Mangan Nib Lug 51 in a desired shape. If a large number of grooves extending linearly in the axial direction are formed on the outer surface of the nib lug 51, a large number of protrusions parallel to the pipe axis will be formed on the inner circumferential wall of the metal tube.

Further, when the smooth plug 52 is rotatably supported on the rod 53 and the protrusion formed by the nib plug 51 and the rolling roll 22 is crushed, the top of the protrusion is crushed as shown in FIG. It is also possible to manufacture a 5° internally grooved tube in which the tube is crushed in one direction and a gap with an inverted cross section is formed in the groove.

Furthermore, a drawing die 41 incorporated in the rotating head 4 at the rear stage
This may be omitted depending on the case, and in that case, the smooth plug 52 and the rolling roll 42 will be responsible for preventing pipe deflection, centering, and finishing the outer surface of the metal tube 5. .

(Effects of the Invention) As described in detail above, according to the internally grooved tube manufacturing apparatus of the present invention, the front stage rotary head having a drawing die and a rolling roll and the rear stage rotary head having at least a rolling roll can be combined into one. By incorporating them into the housing, synchronizing them with a head rotation drive device, and rotating them together in opposite directions, it is easy to balance the rotating bodies, and it is also easy to center the drawing dies and rolling rolls of each head. At the same time, pipe runout can be prevented, and the torsional force due to groove machining can be reduced, so the machining speed can be increased. Moreover, the manufacturing apparatus can be constructed compactly without complicating it, and the internally grooved tube can be manufactured at low cost without requiring equipment costs. Furthermore, a grooved plug that forms a large number of protrusions on the inner circumferential wall surface of the metal tube and a smooth plug that crushes the tops of the protrusions formed by the grooved plug are sequentially attached to the rear part of the floating plug via a rod. Since they are connected, a gap with a bag-like or inverted cross-section is formed in the groove,
An internally grooved tube suitable for boiling evaporation of refrigerant, etc. can be manufactured by a single drawing and rolling process. FIG. 1 is a block diagram of an apparatus for manufacturing an internally grooved tube according to the present invention, and FIG. , FIG. 3 is a partial sectional view of the rolling roll 22 shown in FIG. 1, and FIG. 4 is a sectional view of the rolling roll 42 shown in FIG. 1. 5 is a partial sectional view showing the inner circumferential wall of the metal tube 5 which has been grooved by rolling, and FIG. 6 is a partial sectional view showing the groove shape formed in the inner circumferential wall of the metal tube 5.
7 is a sectional view taken along the line l-Vl, FIG. 7 is a sectional view similar to FIG. 6 showing another form of groove shape formed on the inner circumferential wall of a metal tube, and FIG. 8 is a conventional internally grooved tube. FIG. 2 is a configuration diagram of a manufacturing apparatus.

1...Housing, 2...Pre-stage rotating head, 3...
・Head rotation drive device, 4... Post-stage rotation head, 5.
...metal tube, 21...drawing die, 22...rolling roll, 30...drive shaft, 30a...pinyon gear,
41...drawing die, 42...rolling roll, 50...
... Floating plug, 51 ... Grooved plug, 52 ...
Smooth plug, 53...rod (connecting rod).

Claims (4)

[Claims] (1) A pre-stage rotary head having a drawing die for drawing out a metal tube, and a plurality of rolling rolls for planetary rotation around the outer periphery of the metal tube to be drawn and pressing the outer peripheral wall;
A rear rotary head having a plurality of rolling rolls that planetarily rotates the outer circumference of the metal tube to be drawn and presses the outer peripheral wall of the metal tube is disposed coaxially and in series in the metal tube drawing direction, and these are assembled in the housing. A head rotation drive device synchronizes the rotations of the front and rear rotary heads, and rotates them together in opposite directions, and inserts a float plug into a metal tube facing the drawing die of the front rotary head, and At the rear of the plug, a grooved plug is rotatably disposed in a metal tube facing the rolling roll of the former rotating head and forms a number of protrusions on the inner circumferential wall surface of the metal tube to be pulled out; An internally grooved pipe characterized in that a smooth plug is arranged in a metal pipe facing a rolling roll of a head and is connected in sequence via a rod to a smooth plug that crushes the top of the protrusion formed by the grooved plug. manufacturing equipment. (2) The second stage rotary head has a drawing die, and the first stage rotary head and the second stage rotary head each have the drawing dies and rolling rolls disposed at symmetrical positions. An apparatus for manufacturing an internally grooved tube according to scope 1. (3) The internally grooved tube according to claim 1 or 2, wherein the rolling roll of the first stage rotary head has a roll surface formed into an R surface or a tapered R surface shape. manufacturing equipment. (4) Manufacturing the internally grooved tube according to claim 1 or 2, wherein the rolling roll of the latter rotary head has a roll surface formed into a substantially flat surface shape. Device.