JPS6247090B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus in which a large number of grooves are formed on the inner surface of a tube such as a heat exchange tube.

When forming grooves on the inner surface of a heat exchange tube to improve heat exchange efficiency, conventional groove processing equipment creates grooves over the entire inner surface of the tube, including the cut end. However, when connecting another pipe to the cut end of the tube, there is a drawback that fluid tends to leak at the cut end.
For this purpose, a method has been used in which the heat exchange tube is first expanded at the cut portion, and grooves are formed only in other portions so that grooves are not formed in that portion.

FIG. 1 shows an example of a conventional apparatus in which a plurality of rolling rollers b simultaneously form a plurality of grooves c on the inner surface of an unprocessed metal tube a as a heat exchange tube. As shown in Fig. 2, the rolling roller b is a rolling wheel d in the form of a rhombic rotating body with a shaft e protruding from the center of both sides, and is coaxial with the roller case f inserted into the pipe a. The core metal g moving on a line causes it to protrude slightly from the surface of the roller case f, and the rolling ring d cuts grooves c on the inner surface of the tube a.

Therefore, a groove c is formed on the inner surface of the pipe a, including the cut part thereof, and even if a U-bent pipe is connected to the open end, pinholes will not be formed in the brazed part of the connection surface. This was a major cause of loss of sealing performance.

The present invention has been made in view of the above-mentioned drawbacks, and it is possible to start forming grooves on the inner surface of the tube at an arbitrary distance from the cut end of the heat exchange tube, and to facilitate the processing operation. An object of the present invention is to provide an apparatus for forming grooves on the inner surface of a pipe.

An embodiment of the present invention shown in FIGS. 3 to 7 will be described below.

Reference numeral 1 denotes a cylindrical roller holding cylinder, and a hollow part 2 extending in the axial direction is formed in the center of the cylinder. A plurality of rectangular storage holes 3 are bored in the outer circumferential surface of the roller holding cylinder 1, the positions of which are shifted in stages in the axial direction and the circumferential direction, and each of which is inclined laterally with respect to the axis. It is set up. In this embodiment, there are 7
The arrangement is such that four storage holes 3 are located at 90° intervals from each other in the same cross section in the circumferential direction, but the number and arrangement may be changed as necessary. be able to.

As clearly shown in FIG. 7, each storage hole 3 has an elongated hole portion 3a formed with a slight lateral inclination angle with respect to the axial direction, and a substantially central portion in the longitudinal direction of the elongated hole portion 3a. It consists of recesses 3b, 3b formed on both side walls. On the side of the hollow part 2 of each recess 3b, there is a tongue-shaped bearing part 3c extending from the rear to approximately the center.
is installed protrudingly.

The rolling roller 4 includes a rolling ring 4a shaped like a diamond-shaped rotating body that comes into contact with the inner surface of a pipe to roll grooves, and a rotating shaft 4 of a slightly smaller diameter that is integrally provided on both sides of the rolling ring 4a.
b, and the rolling wheel 4a is the long hole part 3 of the storage hole 3.
The rotary shaft 4b is housed so as to be movable in the front and rear directions within the recess 3b, and can ride on or fall off the bearing 3c within the recess 3b.

As shown in FIGS. 5 and 6, the rolling wheel 4a of the rolling roller 4 sinks into the outer circumferential surface of the roller holding cylinder 1 when the rotating shaft 4b leaves the bearing portion 3c within the storage hole 3. At the same time, when the rotating shaft 4b rides on the bearing portion 3c, it protrudes from the outer circumferential surface of the roller holding cylinder 1.

The outer periphery of the roller holding cylinder 1 is covered by an outer cylinder 5 in which a window 5a corresponding to the storage hole 3 is formed, so that the rolling roller 4 does not fall out from the storage hole 3. Further, a diameter-reducing stepped portion 1a is connected to the rear end of the roller holding tube 1, and a cylindrical push tube 6 having the same diameter as the roller holding tube 1 is fitted and fixed to this diameter-reducing stepped portion 1a. .

Reference numeral 7 denotes a rod that penetrates the inside of the push tube 6 and is inserted into the hollow part 2 of the roller holding cylinder 1 so as to be slidable in the axial direction.
An enlarged head portion 7a having approximately the same diameter as the head portion 7a and gently sloped portions 7b and 7c at the front and rear portions thereof are connected to each other.

Thus, when the expanded head 7a of the rod 7 is out of each storage hole 3, the rolling roller 4 sinks into the storage hole 3, aligning the expanded head 7a of the rod 7 with each storage hole 3, thereby expanding the head. Each rolling roller 4 can be pushed outward in the radial direction at the portion 7a, and the rotating shaft 4b of the rolling roller 4 can ride on the bearing portion 3c.

The groove forming device configured in this manner can form a large number of grooves in a spiral shape from any location on the end of the tube by being inserted into the inner surface of a tube such as a heat exchange tube. Can be done. An example of a groove processing method will be described below with reference to FIGS. 8 and 9.

8 and 9 are explanatory views of the operation, and the rolling roller 4 and the storage hole 3 are inclined laterally by a small angle with respect to the axial direction of the roller holding cylinder 1, and are inclined in the circumferential direction. Although the positions are shifted in stages, for convenience, the rolling roller 3 is shown in the same cross section from the tip to the third row. Therefore, in FIG. 8, although the rolling rollers 3 in the first and second rows are shown to form the same groove 8a on the inner surface of the tube 8, in reality, As mentioned above, each row of rolling rollers 4 forms spiral grooves on the inner surface of the tube 8 that are sequentially shifted by 2π/28 in the circumferential direction.

First, with the roller pushing rod 7 protruding from the tip of the roller holding cylinder 1, move it from the open end (right side in FIG. 8) of the pipe 8 to be processed to the center of the sloped part 7c on the rear side of the rod 7. The grooving device is inserted into the tube 8 until it reaches the place where the inner surface of the tube 8 is to be machined. At this time, all of the rolling rollers 4 are recessed into the roller holding cylinder 1.

Next, fix the rod 7, and then
When the rolling rollers 4 of the first and second rows are moved forward by the outer cylinder 5, the expanded head 7a of the rod 7
are pushed out one after another from the outer peripheral surface of the roller holding cylinder 1, and the rolling ring 4a abuts against the inner wall of the tube 8 and retreats within the storage hole 3 of the roller holding cylinder 1.
The rotating shaft 4b rides on the bearing portion 3c (this state is shown in FIG. 8). As the roller holding tube 1 moves forward, the rolling roller 4 continues to rotate while riding on the bearing portion 3c, thereby forming a groove 8a on the inner wall of the tube 8.

As long as the roller holding cylinder 1 moves forward in the tube 8, the rolling roller 4 engaged with the bearing part 3c is subjected to a force that presses the inside of each storage hole 3 backward, so that the rotating shaft 4b is moved to the bearing part. There is no risk of it leaving 3c.

In FIG. 9, when the formation of the groove 8a is stopped at a predetermined distance from the terminal end of the pipe 8, when the roller holding cylinder 1 is moved backward, the rolling roller 4 is moved around the pipe 8.
The bearing part 3 moves forward in the storage hole 3 under the force of rotation in the opposite direction from the inner wall of the bearing part 3.
The rolling wheels 4a are separated from the rollers 4a and 4a respectively and immerse into the roller holding cylinder 1. The rolling roller 4 inserted into the roller holding cylinder 1 connects this groove processing device to the pipe 8.
When pulling it out from inside, there is no risk of damaging the grooves that have already been formed.

As described above, according to the present invention, when forming grooves on the inner surface of a tube such as a heat exchange tube, processing can be started at an arbitrary distance from the cut end.
A reliable connection is possible to prevent the fluid flowing through the heat exchange tube from leaking at the joint, and there is no need to expand the open end of the heat exchange tube and then process grooves on the inner surface, as was done in the past. The processing process becomes easier. In particular, when attaching a heat sink to multiple hairpin-shaped heat exchange tubes, the conventional method is to expand the tubes when processing the inner grooves, return them to their original state when attaching the heat sink, and then connect the multiple heat exchange tubes with U-bent tubes. However, the groove processing device of the present invention simply simplifies the process. The strength of the joint is maintained without compromising the sealing performance.

Furthermore, according to the apparatus of the present invention, the grooves on the inner surface of the tube can be formed only at desired locations, so it is also possible to create a heat exchange tube in which grooves are continuously carved. In the above embodiment, a spiral groove is formed on the inner surface of the tube, but in order to form a groove parallel to the axis of the tube, the roller holding cylinder 1 is rotated in the same direction as the axis. It is sufficient to provide a storage hole for the forming roller.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing a conventional device for forming grooves on the inner surface of a pipe, FIG. 2 is a front view showing a rolling roller of the conventional device, and FIG. 3 is a diagram showing an embodiment of the present invention. The perspective view, FIG. 4 is also an exploded perspective view,
Figure 5 is a vertical side view of the main part, and Figure 6 is
Fig. 5 is a vertical cross-sectional view taken along the - line, Fig. 7 is a slope view showing the shape of the rolling roller housing hole of the same embodiment, and Fig. 8 is an initial state of the groove forming process according to the same embodiment. The conceptual vertical side view, FIG. 9, is also a conceptual vertical side view showing the final state of the groove forming process. 1...Roller holding tube, 3...Storage hole, 4...
Rolling roller, 5... Outer cylinder, 6... Push pipe, 7...
Rod, 7a... Enlarged head, 7b, 7c... Inclined part, 8... Pipe, 8a... Groove.

Claims (1)

[Scope of Claims] 1. A rolling roller that is formed by integrally protruding small-diameter rotating shafts on both sides of a rolling wheel that rolls grooves by coming into contact with the inner surface of a pipe; A suitable number of rolling roller storage holes are drilled that penetrate to the side hollow part, and the rolling wheel is protruded from the cylindrical peripheral surface by engaging with the rotating shaft of the rolling roller stored in each of these storage holes. A roller holding cylinder is provided with a protruding bearing portion to allow the rolling ring to slide freely in the axial direction within the hollow part on the shaft side of the roller holding cylinder, and the rolling ring is recessed into the circumferential surface of the roller holding cylinder. A device for machining grooves on the inner surface of a pipe, comprising: a rod for pushing up the roller to a state where the rotating shaft of the roller is engaged with the bearing part.