JP3192502B2 - Internal grooved pipe processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an internal grooved tube processing apparatus used for a heat transfer tube such as a heat exchanger.

[0002]

2. Description of the Related Art Internally grooved tubes are widely used as heat transfer tubes for heat exchangers and the like. As a method of manufacturing this inner grooved tube, a plurality of balls or rollers that rotate planetarily outside the tube are attached to the tip of the spindle, the spindle is rotated, and the inner surface is pressed by pressing the grooved plug inserted into the tube. A method of forming a groove has been performed.
17827 and the like.

[0003] Higher performance of the heat exchanger is always strongly desired, and it is desired to improve the performance of the heat transfer tube and to reduce the diameter of the tube, and that the outer diameter is 7 mm or less. By the way, in order to manufacture such a small-diameter pipe, a processing apparatus having a smaller size than before is required, and in order to perform processing with high productivity, it is necessary to increase the rolling speed. However, conventional processing equipment incorporates a rolled ball, a retainer that holds balls at equal intervals, and outer races and stoppers that receive radial and thrust forces acting on the balls. However, it is not possible to obtain sufficient strength just by changing the thickness. In addition, there is a problem that parts interfere with each other when downsizing.

[0004] When the rolling speed is further increased, a torsion force acts greatly on the pipe, and the pipe is easily broken at the start of processing or during processing. In addition, there is a problem that lubrication between the outer race and the metal tube with which the ball comes into contact becomes insufficient, which causes tool friction and adversely affects the surface and groove shape of the tube.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made as a result of studying the above problems, and enables a small-diameter inner grooved pipe to be stably processed at a high speed without breaking during processing. We have developed a processing equipment that can maintain the strength of equipment parts at the same level as before.

[0006]

According to the present invention, a predetermined grooved plug is placed in a metal tube to be drawn and held at a fixed position in the tube, and a position outside the tube corresponding to the grooved plug is set to a hollow shaft. In a processing apparatus for forming a groove in a metal tube by pressing with a plurality of balls revolving attached to a shaft end of a motor or a spindle, a diameter reducing die for reducing the diameter of the metal tube on the entrance side of the hollow shaft. Through the hollow shaft, and into the shaft on the outlet side of the hollow shaft, an empty die for reducing the diameter of the tube along the tube withdrawing direction, an outer race that expands in the withdrawal direction and determines the rotation trajectory of the ball, and a ball. A ball retainer that holds the ball at equal intervals and has an opening on the tube withdrawal side of the part that holds the ball, and a ball retainer that is located on the ball withdrawal side and is supported from outside the rotating shaft and receives a thrust force acting on the ball Having a stopper The inner race grooved pipe processing device according to claim 1, wherein the stopper is rotatably supported, and the inner grooved tube processing device according to claim 1, wherein the outer race is formed. An inner ring grooved pipe processing apparatus according to claim 1, further comprising an adjusting ring movable in a pipe drawing direction, wherein the ball is in contact with a metal pipe and an outer race. A lubricating oil supply hole for supplying lubricating oil is provided.

[0007]

According to the processing apparatus of the present invention, since the ball retainer has an opening, the strength is maintained even if each component is downsized, and a small-diameter inner grooved pipe is manufactured without interfering with each other. be able to. Further, since the diameter is reduced by the die immediately before the groove processing, the processing speed can be improved in order to prevent the pipe from being twisted due to high-speed rotation. The apparatus of the present invention can produce a grooved tube having a triangular groove, a trapezoidal groove, or other shapes.

[0008]

An embodiment of the present invention will be described below.
FIG. 1 is a cross-sectional view of the inner grooved pipe processing apparatus of the present invention, and FIG. 2 is an enlarged cross-sectional view of the vicinity of a grooved portion in FIG. In the figure, reference numeral 1 denotes a metal pipe to be processed, and a connecting rod 5 is provided in the pipe.
The grooved plug 7 connected to the floating plug 3 is inserted, and is held at a fixed position by the reduced-diameter die 4 and the floating plug. Then, the ball 6 presses the metal tube while revolving around the outside of the tube corresponding to the grooved plug, and a groove is formed on the inner surface.

The balls are held at equal intervals on the circumference of the tube by a ball retainer 9 having an opening in a part of the hole. The inner race is formed by an outer race 8 having a tapered surface diverging in the traveling direction of the metal tube. Its radial position is determined.

Further, regarding the thrust force acting on the ball at the time of groove processing, the ball travel direction side (pipe drawing direction)
The ball is supported by a stopper 10 having a plane perpendicular to the tube axis to position the ball. The stopper is housed in a non-rotating head cover 19 and is rotatably supported by bearings or the like. The stopper does not need to be rotatable, but may be fixed directly to the case to support the ball.

In processing the metal pipe, first, the diameter is reduced by the diameter reducing die 4 and the floating plug 3, and then, the hollow die 14 is first passed through the hollow shaft 14 and the other end shaft. To slightly reduce the diameter. Since the idle die is housed in the shaft via a bearing, the die does not rotate even if the hollow shaft rotates. The diameter reduction is performed in order to prevent the pipe from being twisted and broken at the time of processing at a high speed rotation, and a large diameter reduction rate is not required. Has a sufficient effect. The reduced diameter metal tube is reduced in diameter by a ball 6 pressing the outer surface of the tube while revolving around the outside of the tube, and the material is pressed against the surface of the grooved plug inserted into the tube to form an inner surface groove. The ball is revolved by rotating the outer race 8 at a high speed, but since the outer race has a tapered surface on the inner surface, the radial position of the ball can be changed by changing the thickness of the adjusting ring 15.

In the figure, when the outer race is moved in the direction of travel of the metal tube, the revolving radius of the ball becomes smaller, and the amount of pressing the tube becomes larger. As a method of driving the rotating shaft, a method incorporating a motor as shown in this figure may be used, or a method of rotating the rotating shaft of the spindle from outside via a coupling or a belt may be used. . During processing, the thrust force acting on the ball is supported by the stopper 10 so as to be rotatable and rotatable outside the rotation axis as described above, but even if the contact surface with the ball is perpendicular to the tube axis, A stopper with an inclination of may be used.

Since the ball retainer 9 partially has the opening 18 as shown in FIG. 3, the ball retainer 9 can provide sufficient strength even if it is miniaturized without interference with a stopper, and it can be used for a processing part. A lot of space can be obtained so that lubrication can be easily performed. That is, in the high-speed rotation, not only the heat generated by the plastic working but also the heat generated by the rotation itself is large.
It can be provided in at least two directions, and sufficient lubrication can be performed not only at the contact position between the metal tube and the ball but also at the contact portion between the ball and the outer race, facilitating high-speed rotation.

Further, the fine metal powder generated at the time of processing can be easily discharged together with the lubricating oil through the oil discharge hole 17. Numeral 12 is a diameter adjusting soy provided for adjusting the outer diameter of the grooved metal pipe. Since the diameter adjusting soy is arranged on the head cover 19 integrated with the motor while maintaining the concentric accuracy, only the dimensional accuracy is high. However, since it is near the grooved portion, it is useful for preventing the pipe from being twisted.
Using the above apparatus, an inner grooved tube with an outer diameter of 4 mm was machined at a revolution speed of 35,000 rpm.
It was possible to stably manufacture a tube having the same quality as that of a conventional grooved tube with an inner surface, and it was possible to improve the processing speed by about twice.

[0015]

According to the present invention as described above,
A small-diameter inner grooved pipe can be manufactured at a high speed without breaking, and has a remarkable industrial effect.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an internal grooved pipe processing apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of the vicinity of a grooved portion in FIG.

FIG. 3 is a perspective view of a ball retainer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal tube 2 Inner surface grooved tube 3 Floating plug 4 Reduced diameter die 5 Connecting rod 6 Ball 7 Groove plug 8 Outer race 9 Ball retainer 10 Stopper 11 Emptying die 12 Diametering die 13 Motor 14 Hollow shaft 15 Adjustment ring 16 Lubricating oil supply hole 17 Oil discharge hole 18 Opening 19 Head cover

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-3-281013 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21C 1/22 B21C 3/08

Claims (4)

(57) [Claims] 1. A predetermined grooved plug is placed in a metal tube to be drawn and held at a fixed position in the tube, and a position outside the tube corresponding to the grooved plug is set to a motor or spindle shaft having a hollow shaft. In a processing device that is pressed by a plurality of revolving balls attached to the end to form a groove in a metal pipe,
An emptying die for reducing the diameter of the tube along the pipe drawing direction in the shaft on the outlet side of the hollow shaft through a reduced diameter die for reducing the diameter of the metal tube on the entrance side of the hollow shaft and the hollow shaft; An outer race that spreads in the direction and determines the rotation trajectory of the ball,
A ball retainer that holds the ball at equal intervals and has an opening on the tube withdrawal side of the part that holds the ball, and a thrust force that is located on the ball withdrawal side of the ball and is supported from outside the rotating shaft and acts on the ball An inner grooved pipe processing device characterized by having a stopper for receiving the groove. 2. The apparatus according to claim 1, wherein said stopper is rotatably supported. 3. The outer race is provided with an adjusting ring movable in a pipe drawing direction.
An inner grooved pipe processing apparatus as described in the above. 4. The internal grooved pipe processing apparatus according to claim 1, wherein a lubricating oil supply hole for supplying lubricating oil is provided at a portion of the metal tube in contact with the ball and an outer race.