JPH0899206A - Removal of inner fin from heat exchanger tube with inner fin - Google Patents

Abstract

PURPOSE: To get rid of the occurring of burrs and the remaining of chips, to very smoothly carry out partial removal of an inner fin, and to prevent aluminum chips from mixing with fluid, as oil, in a method in which a part of an inner fin is cut and removed by a drill from an end part of a heat exchanger tube having inner tubes made of extruded aluminum material. CONSTITUTION: A cutting work assisting block 11, which has a recessed groove 12 in its peripheral surface, is inserted into the inside of an end part 1a of a heat exchanger tube 1 made of extruded aluminum material in such a manner that an inner fin 2 is fitted into the recessed groove 12. A part of inner fin 2, which is located in this side than the cutting work assisting block 11, is removed by a drill 10, which is inserted from the end part 1a on the same side of the heat exchanger tube 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing inner fins in a heat exchange tube with inner fins used in, for example, an oil cooler for power steering.

[0002]

2. Description of the Related Art Conventionally, a heat exchange tube made of an extruded aluminum material having an inner fin therein has been used as a heat exchange tube used in an oil cooler for power steering. This is to increase the surface area inside the tube and to increase the heat transfer to the outside or the inside with respect to the fluid passing therethrough. Since this heat exchange tube with inner fins is required to have high heat exchange performance, outer fins are further brazed or mechanically attached, and both ends of the heat exchange tube are narrowed to a small diameter. Each inlet and outlet pipe was attached by welding, and the hose connecting to the pump system was connected. Further, in order to prevent the hose from coming off, a beading process was applied to the end of the inlet / outlet pipe to form a hose removal preventing convex portion in an annular shape.

[0003]

However, in the case of a heat exchange tube with an inner fin made of aluminum extruded profile as described above, both ends of the tube itself are narrowed to a small diameter and beading to these ends. When it was attempted to form an annular hose disconnection preventing convex portion by processing, such processing was difficult unless the inner fin was removed inside the end portion of the heat exchange tube.

Therefore, as a method of removing the inner fin from the end of the heat exchange tube, cutting with a drill can be considered. However, when the inner fin is removed from the inside of the end of the heat exchange tube using the drill, the inner fin is removed. There is a problem that burrs may occur at the boundary between the removed portion and the residual portion, or cutting powder may remain inside the pipe, causing the aluminum cutting powder to be mixed with the oil when the oil is circulated. It was

The object of the present invention is to solve the above-mentioned problems of the prior art, and to remove the inner fin even if a part of the inner fin is cut and removed from the end of the heat exchange tube made of aluminum extruded profile with a drill. No burr is generated at the boundary between the remaining part and the remaining part, and the cutting powder does not remain inside the pipe, and there is no mixing of aluminum cutting powder into the fluid such as oil, and the partial removal of the inner fin is extremely smooth. In addition, both ends of the heat exchange tube itself after removing the inner fins can be swaged to reduce the diameter to a small diameter, and it is not necessary to attach a conventional inlet / outlet pipe to the end of the heat exchange tube. Inner fin removal method for heat exchange tubes with inner fins, which can reduce the manufacturing cost of the heat exchange tubes with fins and does not worry about leakage of fluid such as oil In the attempt to provide.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a large number of inner fins, which are provided on the inner surface of a heat exchange tube made of an extruded aluminum profile and extend in the longitudinal direction, of the heat exchange tube. A method of cutting and removing from one end with a drill, wherein a cutting assistance block having a groove for fitting an inner fin on the outer peripheral surface is provided inside the one end of the heat exchange tube, and the inner fin is fitted in the groove. An inner fin for a heat exchange tube with an inner fin, characterized in that the inner fin portion before the cutting assistance block is cut and removed by a drill inserted so that it fits together and inserted from the same end of the heat exchange tube. The removal method is the main point.

Block for cutting assistance (that is, core)
Is approximately equal to the inner diameter of the heat exchange tube with inner fins,
Alternatively, it has a slightly smaller outer diameter and at least the same number as the inner fins of the heat exchange tube and the inner fin fitting recessed grooves extending in the longitudinal direction on the outer peripheral surface.

Here, when the cutting assistance block is inserted into the heat exchange tube with the inner fin, the clearance between the peripheral wall of the cutting assistance block and the tube wall, and both side walls of the concave groove of the block and the inner fin is set. , 0.3 mm or less, preferably 0.01 mm to 0.3 mm, desirably 0.05 mm to 0.
It is 2 mm or less.

If the gap exceeds 0.3 mm, it is impossible to prevent the inner fins contained in the concave grooves of the cutting assistance block from collapsing when the inner fins are cut and removed by a drill, and the inner fins are prevented from falling. Burrs are generated at the boundary between the removed portion of the fin and the remaining portion, and cutting powder remains inside the pipe, which is not preferable. However, if the gap is too small, not only is it difficult to manufacture the cutting assistance block, but also it becomes difficult to insert the cutting assistance block inside the heat exchange tube with inner fins.

Further, a cutting assistance block may be attached to the tip of the drill in advance, and the drill with the cutting assistance block may be inserted from the end of the heat exchange tube with the inner fin. May be separated from each other, and the tip of the drill may be inserted after the cutting assisting block is inserted before the end of the heat exchange tube with inner fins. Insert the cutting aid block held at the end of the horizontal bar from the end on the opposite side of the heat exchange tube with inner fins, while inserting the tip of the drill from one end of the heat exchange tube. Alternatively, the inner fin may be removed by cutting while hitting the block.

[0011]

According to the above method, the cutting aid block having the inner fin fitting concave groove on the outer peripheral surface is provided inside one end of the heat exchange tube with the inner fin, and the inner fin is fitted in the concave groove. The inner fin portion in front of the cutting assistance block is cut and removed by a drill inserted so that it fits and inserted from the same end of the heat exchange tube.

When the inner fin portion is cut and removed by this drill, the inner fins housed in the concave groove of the cutting assistance block are held by the side walls of the concave groove so that the inner fin is prevented from falling. Therefore, the inner fin portion in front of the cutting assistance block can be removed extremely smoothly, and burrs are generated at the boundary between the removed portion of the inner fin and the remaining portion, and cutting powder remains inside the pipe. There is nothing to do.

Therefore, even when the heat exchanger tube with inner fins, from which the inner fins are removed by a predetermined length from the inside of both ends in this way, is used as, for example, an oil cooler, the aluminum cutting powder becomes oily as in the conventional case. There is nothing that gets mixed in.

After further removing the inner fin portion of the required length, both ends of the heat exchange tube with aluminum fin made of extruded aluminum shape itself are swaged to reduce the diameter to a small diameter, and beading to these ends. Since the annular hose disconnection prevention convex portion can be formed by processing, it is not necessary to attach a conventional inlet / outlet pipe to both ends of the heat exchange pipe by welding, and the manufacturing cost of the heat exchange pipe with inner fins can be reduced. It is a thing.
Further, since it is not necessary to attach an inlet / outlet pipe as a separate article to both ends of the heat exchange pipe, there is no fear of fluid leakage at the inlet / outlet pipe connecting portion.

[0015]

Embodiments of the present invention will now be described with reference to the drawings.

1 to 6 show a first embodiment of the present invention.

First, in FIGS. 1 to 4, a heat exchange tube (1) made of extruded aluminum is provided with inner fins (2) extending in the longitudinal direction, six inner fins (2) alternately and radially. Is equipped with.

On the other hand, the cutting assisting block (11) is provided with inner fin fitting recessed grooves (12) each having a U-shaped cross section, each of which has a size of 6 and a size in which the inner fins (2) are fitted on the outer peripheral surface thereof. Has been. Further, a through hole (13) for inserting a drill tip is formed in the center of the block (11).

In this embodiment, the tip (10) of the drill (10) is
a) has a small diameter, and the drill tip (10a) is inserted into the through hole (13) in the central part of the cutting assistance block (11),
A nut (15) is screwed onto a male screw portion (14) projecting forward from the block (11), and the cutting assistance block (11) is attached to the tip portion (10a) of the drill (10).

In the above, in order to partially remove the inner fin (2) of the heat exchange tube (1) from the end of the tube, as shown in FIG. 1, a drill with a cutting assistance block (11) ( 1
Insert the tip (10a) of (0) into the inside of one end (1a) of the heat exchange tube (1), and insert it into the groove (12) on the outer peripheral surface of the block (11).
Insert the inner fin (2) on the (1) side. In this state, the drill (10) is rotated to partially cut and remove the inner fin (2).

A gap between the inner wall of the heat exchange tube (1) and the cutting assistance block (11) and between both side walls of the groove (12) of the block (11) and the inner fin (2). Is 0.1 mm,
A trial test was conducted by setting three levels of 0.2 mm and 0.3 mm.

In any of the above cases, the inner fin housed in the concave groove (12) of the cutting assistance block (11).
(2) is held so that it will not fall over by the side walls of the groove (12), so the inner fin (2) part in front of the cutting aid block (11) can be cut off very smoothly. As a result, no burr was generated at the boundary between the removed portion and the remaining portion of the inner fin (2), and no cutting powder remained inside the pipe.

Next, as shown in FIGS. 5 and 6, the heat exchange tube in which the inner fins (2) are partially removed as described above.
Both ends (1a) and (1a) of (1) are pressed from the outside by swaging to reduce the diameter, and the part of the reduced pipe end (1a) near the tip is beaded. An annular hose disconnection preventing protrusion (3) was formed.

The heat exchange pipe (1) shown in the figure has a substantially U-shape which is bent when viewed from the front, and is provided with intermediate straight pipe portions (1b) (1b) excluding both end portions (1a) (1a) thereof. Install the outer fins (4) to fit the inner fins (2) and outer fins (4).
A heat exchange tube (1) having a

When the heat exchange tube (1) having the inner fins (2) and the outer fins (4) is used as an oil cooler, aluminum cutting powder may be mixed with oil as in the conventional case. There was none. Further, since it is not necessary to attach an inlet / outlet pipe as a separate article to both ends (1a) (1a) of the heat exchange pipe (1), there is no fear of fluid leakage at the inlet / outlet pipe connecting portion.

Further, in this embodiment, since the inner fins (2) inside the heat exchange tube (1) are formed in a radial shape, the heat transfer area is very large, and thus the obtained heat transfer area is obtained. The heat exchange tube (1) had excellent heat exchange performance.

FIG. 7 shows a second embodiment of the present invention. Here, the difference from the case of the first embodiment is that
Insert the cutting aid block (11) held at the end of the horizontal bar (16) with the handle (17) from the end on the opposite side of the heat exchange tube (1) with the inner fin (2). The point is that the tip of the drill (10) is inserted from one end of the heat exchange tube (1) and the inner fin (2) is removed by cutting while abutting against the block (11).

In the first embodiment, the cutting assistance block (11) is previously attached to the tip portion (10a) of the drill (10), and the drill (10) with the cutting assistance block (11) is attached to the inner fin. (2) It is inserted from the end of the heat exchange pipe (1) with a drill, but in some cases, the drill (10) and cutting aid block
(11) should be separated from each other, and the cutting aid block (11) should be placed before the end of the heat exchange tube (1) with inner fin (2).
After inserting, the tip of the drill (10) may be inserted and the inner fin (2) may be removed by cutting while pushing the block for cutting assistance (11).

The heat exchange pipe (1) having the inner fins (2) produced by the method of the present invention is used not only for the oil cooler but also for other radiators and car cooler evaporators and condensers. Is.

[0030]

As described above, according to the present invention, a large number of inner fins provided on the inner surface of a heat exchange tube made of extruded aluminum and extending in the longitudinal direction are removed by cutting from one end of the heat exchange tube with a drill. In the method, a cutting assistance block having an inner fin fitting concave groove on the outer peripheral surface is inserted inside one end of the heat exchange tube so that the inner fin fits into the concave groove, With the drill inserted from the same end of the exchange pipe, the inner fin portion before the cutting assistance block is cut and removed. According to the present invention, the inner fin is drilled from one end of the heat exchange pipe with inner fin. When removed by cutting using, the inner fins housed in the groove of the cutting aid block are held by both side walls of the groove so that they do not fall down. The inner fin portion in front of the auxiliary block can be cut and removed very smoothly, and burrs are generated at the boundary between the removed portion of the inner fin and the remaining portion, and cutting powder remains inside the pipe. There is no such thing.

Therefore, even when the heat exchange tube with inner fins whose inner fins are removed from the inside of both ends by a predetermined length in this way is used as, for example, an oil cooler, the aluminum cutting powder becomes oily as in the conventional case. There is nothing that gets mixed in.

After removing the inner fin portion having the required length, both ends of the heat exchange tube with an inner fin made of extruded aluminum are squeezed to a small diameter by swaging, and beading to these ends. Since the annular hose disconnection prevention convex portion can be formed by processing, it is not necessary to attach a conventional inlet / outlet pipe to both ends of the heat exchange pipe by welding, and the manufacturing cost of the heat exchange pipe with inner fins can be reduced. It is a thing.

Further, since it is not necessary to attach an inlet / outlet pipe as a separate article to both ends of the heat exchange pipe, there is no fear of fluid leakage at the inlet / outlet pipe connecting portion.
As a result, it is possible to easily and inexpensively manufacture a heat exchange tube with an inner fin having excellent heat exchange performance.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a process of a first embodiment for removing inner fins by the method of the present invention.

FIG. 2 is a side view of a disassembled state of a drill and a cutting assistance block.

FIG. 3 is an enlarged cross-sectional view taken along the line AA of FIG.

FIG. 4 is a front view of only a cutting assistance block.

FIG. 5 is a front view of a heat exchange tube having inner fins and outer fins.

FIG. 6 is a partially cutaway front view showing an enlarged main part of the heat exchange tube of FIG.

FIG. 7 is a schematic cross-sectional view showing the steps of the second embodiment of removing the inner fins by the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat exchange tube made of extruded aluminum material 1a One end of heat exchange tube 2 Inner fin 10 Drill 11 Cutting aid block 12 Inner fin fitting concave groove

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Shida 6-224, Kaiyama-cho, Sakai City, Showa Aluminum Co., Ltd. (72) Inventor Watabe Ho, 6-224, Kaiyama-cho, Sakai City

Claims (1)

[Claims] 1. A large number of inner fins (2) provided on the inner surface of an aluminum extruded shape heat exchange tube (1) and extending in the longitudinal direction are drilled from one end (1a) of the heat exchange tube (1). Ten)
It is a method of cutting and removing with an inner fin fitting concave groove on the outer peripheral surface inside the one end (1a) of the heat exchange tube (1).
A block (11) for cutting assistance having (12) is provided with a groove (1
Insert the inner fin (2) so that it fits into 2), and insert it from the same side end (1a) of the heat exchange tube (1) with the drill (10) that is in front of the cutting assistance block (11). A method for removing inner fins in a heat exchange tube with inner fins, which comprises removing the inner fins (2) by cutting.