JPS5816748A - Narrow groove working method on inside surface of pipe - Google Patents

Abstract

PURPOSE:To work a groove which leaves no original cylindrical surface on the inside surface of a pipe, by constituting so that a groove working part of a rolling wheel provided with plural groove working parts at a necessary pitch is guided by a groove cut in advance. CONSTITUTION:To the front half of a cylindrical holder 4, a rolling wheel is installed, and the half number of grooves are worked at a pitch of 2 times of its finally necessary groove pitch. Subsequently, to the rear half of the holder 4, a rolling wheel 5 having a wheel tread is installed in such relation as a groove forming part 6a and 6b coincide with a groove 3a and a groove 3b, respectively, so that the forming part 6a and 6b are guided by 3a and 3b, respectively, from the time when a tool is pushed into a pipe. In this way, a pipe which is suitable for condensing heat transfer can be manufactured, and it is also possible to manufacture a pipe having a large effect for both boiling heat transfer and condensing heat transfer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a large number of narrow grooves on the inner surface of a tube, and particularly for forming a groove shape that is effective for condensing heat transfer on the inner surface of a tube. A preferred method.

The conventional method of machining a large number of narrow grooves on the inner surface of a pipe is to place a rolling wheel with a tread of the same shape as the groove in a cylindrical holder, and when viewed in the projection view in the axial direction of the cylinder, each of the rolling wheels There is a method of machining a large number of narrow grooves on the inner surface of a pipe using a rolling tool installed in the same number of grooves so that the position of the rolled part matches the required shape pitch of the grooves. According to this method, the narrow grooves 6 can be easily formed on the inner surface 2 of the tube 1 as shown in FIG. This method was effective in manufacturing tubes like the one shown in the figure. However, when used as a heat transfer tube, it was found that although the tube shown in Figure 4 had excellent heat transfer performance in boiling heat transfer, it was less effective in condensing heat transfer. In the case of condensation heat transfer, a pointed part 7 like the number 7 in Fig. 5 is required, but in the conventional processing method,
If the groove shape is not such that the original cylindrical surface 2 remains on the inner diameter of the pipe, the rolling wheel that attempts to roll the groove later into the adjacent groove will derail and fall, making it impossible to machine the required number of grooves at the required pitch. there were.

An object of the present invention is to provide a technique that makes it possible to process grooves that do not leave the original cylindrical surface on the inner diameter of a tube using tools similar to those used in conventional methods.

In the conventional method, the rolling wheel falls into an already machined groove only when adjacent grooves are machined. One or more of the machined parts runs inside the already machined groove and guides it, so that the newly formed part to be grooved will not derail even if the original cylindrical surface is narrow. This is what I did.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

When machining a tube with a groove shape that does not leave the original cylindrical surface on the inner surface of the tube as shown in FIG. 5, first attach a rolling ring as shown in FIG. As shown in Figure 6, half of the grooves are machined at a pitch that is twice the final groove pitch. Next, in the latter half of the holder 4, a rolling wheel having a tread surface as shown in FIG. 7 is arranged so that the groove forming part 6a in FIG. 7 matches the groove 6a in FIG. 6, and the groove 6b matches the groove 6b in FIG. When the molded parts 6a are picked up and pushed into the tool or tube, the molded parts 6a are guided by 6a, and the molded parts 6b are guided by 6b.

As a result of the above, even if the cylindrical portion 2 of A-C in FIG. 6 is widened, 6c will not derail into 6a or 6b,
In addition, in this embodiment, the molded parts 6a and 6b are
Since the cross section is larger than the guide groove of 5b, 7.
The a and 7b portions can be raised higher inward than the 2nd surface. Of course, it is also possible to match the shapes of 6a, 6b and 6a, 6b, and 6c without any problem.

Also, only 6a and 6b may be made to match the shape of 38 and 3b, and only 6c may be made to have a wide bottom shape,
The opposite may be true.

When using a rolling ring with a plurality of grooved parts as in the present invention, the force with which one rolling wheel pushes the tube in the radial direction becomes large, so the outer diameter of the tube is clamped as shown at 8 in Fig. 8. It is common practice to process the material in the same state.

As described above, according to the present invention, in the conventional method, I? ,
4 Although only tubes that can improve boiling heat transfer as shown in Figure 1c and 7'c could be obtained, it is also possible to produce tubes that are suitable for condensing heat transfer as shown in Figure 5). ,
It is also possible to manufacture a tube that is highly effective in both boiling heat transfer and condensation heat transfer, as shown in FIG.

In addition, if the tube is thin or the groove is deep, use the holder 4 in Figure 2.
However, even if the cylindrical surface 2 remains due to twisting during processing due to the thinness of the cylindrical surface 2, derailment may occur, but this can be prevented by the method of the present invention.

According to the present invention, it is now possible to process internally grooved tubes with a groove shape that leaves no original cylindrical surface on the inner surface, which was impossible with conventional processing methods. We can process transmission pipes and pipes that combine both functions without any restrictions. In addition, it has become easier to process thin tubes and tubes made of materials with high deformation resistance, which were previously fixed points. As a result of the above, the performance of the heat exchanger has been improved.

It is possible to reduce the size and provide an effective means for saving energy and resources.

[Brief explanation of the drawing]

Figure 1 is an external view of an internally grooved tube, and Figure 2 shows the conventional groove processing method. frlfr diagram, Figure 6 is a front view of the rolling wheel, Figure 4 is a cross-sectional view of an internally grooved tube suitable for boiling and seepage heat transfer, and Figure 5 is a front view of the rolling wheel.
The figure is a cross-sectional view of an internally grooved tube suitable for condensation heat transfer, Figure 6 is a cross-sectional view of the first half of processing in an embodiment of the present invention, and Figure 7 is a front view of a rolling wheel in an embodiment of the present invention. FIG. 8 is a sectional view showing a groove processing method according to an embodiment of the present invention, and FIG. 9 is a sectional view of an internally grooved tube suitable for both boiling and condensing heat transfer states. 1...Inner grooved tube, 2...Remaining circular part on the inner surface of the raw tube,
5... Groove, 4... Holder, 5... Rolling wheel, 6...
...Rolling ring groove forming part, 7...Groove raised part, 8...
Pipe outer diameter restraint clamp. '#15a

Claims (1)

[Claims] 1. A rolling wheel having a tread having the same shape as the groove is mounted on a cylindrical holder, and when viewed in a projected view in the axial direction of the cylinder, the position of each groove rolling portion of the rolling wheel is In this method, many narrow grooves are machined on the inner surface of the pipe using a rolling tool to match the required pitch of the grooves, and when machining adjacent grooves, the required pitch is A tube inner surface characterized by using a rolling ring having a plurality of grooved parts, and arranging the rolling ring so that one or more of the grooved parts is guided by an already cut groove. Fine groove processing method. 2. The method for forming narrow grooves on the inner surface of a tube according to claim 1, wherein the remaining grooves are formed using a rolling wheel having a processing section and using the groove formed in the first half as a guide. 6. The groove shape of the first half with twice the pitch is different from the groove shape of the second half, so that when the rolling wheel for forming the groove in the second half is guided, it is guided while correcting the groove shape cut in the first half. A method for forming narrow grooves on the inner surface of a tube according to claim 2.