JPH09108759A - Automatic aligning device for metal tube internal working device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely align between the center of a metal tube to be worked and the center of a tool inserted. SOLUTION: When a cutting tool 3 is inserted into the inside of a metal tube 1 through a drive shaft 2 and the inner wall of the metal tube 1 is worked by mutually rotating the cutting tool 3 and metal tube 1, a steel shaft 11, which is provided with a tool mounting part 11a to mount a tool at its tip, a conical face 11c formed adjacent thereto and an engaging part 11b formed adjacent thereto, is arranged. A cylindrical ball holding tool 12 is externally fitted over the cutting tool mounting part 11a, conical face 11c and engaging part 11b, plural steel balls are locked to the ball holding tool 12 as rotatable and being in contact with the conical face 11c, the ball holding tool is energized in the working direction by a spring 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic metal pipe inner surface machining apparatus for aligning the center of rotation of a cutting tool, which is a tool for machining a spiral groove on the inner surface of a metal pipe, with the center of the metal pipe. The present invention relates to an aligning device.

[0002]

2. Description of the Related Art For example, when making a heat transfer tube having fins for heat exchange on the inner wall surface, a bit is inserted into the tube to form a spiral groove on the inner wall of the metal tube (for example, a spiral fin). Has been given. FIG. 4 is a cross-sectional view showing the configuration of an apparatus for forming a spiral groove on the inner wall of a metal tube. Here, an example is shown in which a spiral fin is formed on the inner wall of the metal tube while reducing its diameter.

A drive shaft 2 is inserted into a cylindrical metal tube 1, and a cutting tool 3 is attached to the tip of the drive shaft 2 rotated by a drive source (not shown). This byte 3 is shown in Figure 6.
It has two blades 3a and 3b. Further, a cylindrical hollow sleeve 4 is externally fitted near the cutting tool 3 and plays a role of supporting the drive shaft 2 around the shaft center. In order to prevent horizontal movement of the hollow sleeve 4, the drive shaft 2 is provided with stoppers 5a and 5b. In addition, a jig (drawing die) 6 is provided near the position where the cutting tool 3 is located so as to be fitted onto the metal tube 1. The inner diameter of the jig 6 is set to be slightly smaller than the outer diameter of the metal tube 1, and the metal tube 1 is narrowed down by pushing in (or pulling out) the metal tube 1.
Is processed to the inner diameter of.

At the time of processing, as shown in FIG. 4, the tip of the metal tube 1 is pressed against the jig 6 to reduce the outer diameter, and then the drive shaft 2 having the cutting tool 3 mounted therein is inserted into the metal tube 1. (Alternatively, the drive shaft 2 on which the bite 3 has been mounted is inserted into the metal tube 1). After that, as shown in FIG. 5, while rotating the drive shaft 2, the jig 6 is moved from the position of FIG. 4 to the cutting tool 3 side by the distance L, and the inner surface of the jig 6 is opposed to the blades 3a and 3b.
Ensure that cutting with the cutting tool 3 is performed stably. The drive shaft 2 is rotated while the jig 6 is fixed, and at the same time, the metal tube 1 is rotated.
Is moved in the direction of the arrow, the spiral fin 7 in the direction orthogonal to the axis is continuously lifted up on the inner wall of the metal tube 1.

FIG. 7 is a sectional view showing another conventional structure of an apparatus for forming a spiral groove on the inner wall of a metal tube. In FIG.
In addition to the jig 6, the jig 8 having a larger inner diameter than the jig 6 is provided. Along with this, the floating plug 9 is used, and the bite 3 is held at the axial center by the floating plug 9.

The floating plug 9 is arranged at a position facing the jig 8, and the bite 3 is arranged at a position facing the jig 6. And the floating plug 9
The outer diameter is configured in two steps, and the step portion has an inclined surface, and this inclined surface is set to an angle equal to the inclination angle of the entrance side inclined surface of the jig 8. Since the floating plug 9 has a step in the outer diameter, only one stopper 10 is provided on the rear end side to restrict this movement, and the tip side is restricted by the stepped portion. In the configuration of FIG. 7, since the metal tube 1 is processed while being held at two places, it is easy to keep the inner diameter and wall thickness of the tube accurately, and the processing can be performed stably.

Regarding this kind of technology, for example,
Japanese Examined Patent Publication No. 1-54135 discloses that a cylindrical guide portion and a fin-forming tool, a gear-shaped tool, a fin-forming portion, etc. are mounted on the tip of the guide portion in the metal pipe, and the metal pipe and the metal pipe are axially opposed to each other. The fins can be formed without moving and welding.

[0008]

However, in the above-mentioned prior art, it is necessary to match the pipe axis and the center of rotation of the cutting tool as accurately as possible. For this purpose, the outer diameter of the hollow sleeve and the inner diameter of the tube must be matched. The difference between and must be reduced.
However, a relatively large gap is required for insertion inside a long pipe, which exceeds the allowable limit of variation in the cutting depth of the cutting tool which is required in practice.

Further, the inner diameter of the metal tube to be processed varies depending on the manufacturing lot, and in order to deal with each, a large number of sleeves having slightly different outer diameters must be prepared and replaced each time. ,troublesome. Further, in the configuration of FIG. 7, it is easy to keep the inner diameter and wall thickness of the pipe accurately,
Although stable processing can be performed, there are the following problems.

A) Machining cannot be performed unless jigs are attached at two axial positions and three relative members in the axial direction are changed in cooperation with each other, and the mechanism of the apparatus and the machining operation become complicated. Become. b) The resistance force applied to the pipe at the floating plug portion becomes extremely large, which makes it difficult to process a thin-diameter or thin-walled pipe.

The present invention has been made in view of the above-mentioned prior art, and provides an automatic centering device for accurately centering the center of a metal tube to be machined and the center of an inserted working tool. It is intended to be provided.

[0012]

To achieve the above object, the present invention inserts a working tool into a metal tube, relatively rotates the working tool and the metal tube, and axially moves the tool. In a metal pipe inner surface processing apparatus for processing the inner wall of the metal pipe by relatively moving to, a large-diameter processing tool mounting portion on which the processing tool is mounted at the tip, a conical portion formed so as to contact this portion, And a plurality of metal spheres provided with a small diameter portion formed so as to be in contact with the conical portion, and in contact with the conical portion of the shaft and the inner surface of the metal tube and rotatably arranged. A tubular holder for holding the metal ball fitted to the narrow diameter portion and the processing tool mounting portion so as to maintain a substantially horizontal state, and the holder for processing the metal pipe. And a biasing means for biasing in the direction.

In this case, the shaft body may be provided in multiple stages in the axial direction, and the processing tool, the holder provided with the metal balls, and the biasing means may be provided in each stage. . According to the above-mentioned means, the plurality of metal balls arranged so as to be in contact with the conical portion formed in a part of the shaft body are urged toward the processing position by the holder for rotatably locking the metal balls. By contacting the inner wall surface of the metal tube with a predetermined pressure,
By functioning as a bearing, the center of the processing tool and the center of the metal tube can be aligned with each other, and the aligned state can be stably maintained. As a result, it becomes possible to perform centering easily and accurately.

Furthermore, by providing the holder provided with metal balls and the self-aligning mechanism having the urging means in multiple stages in the axial direction, the number of places where the metal tube is supported from the inside increases, and the length of the long metal tube is increased. It can also be processed.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. [Embodiment 1] FIG. 1 is a front sectional view showing an embodiment of an automatic centering device according to the present invention. FIG. 2 shows FIG.
2 is a sectional view taken along line AA of FIG.

The automatic centering device according to the present invention comprises a drive shaft 2
The steel shaft 11 (second shaft) mounted on the tip of the (first shaft) and having the bite 3 mounted on its tip is used as the shaft portion. The steel shaft 11 may be manufactured as a single component, or may be integrally formed on the tip of the drive shaft 2 by a lathe or the like. Steel shaft 11 is 3
A part, that is, a bite mounting portion 11a to which the bite 3 is mounted and has an outer diameter substantially equal to the outer diameter of the drive shaft 2, the drive shaft 2
Engaging portion 11b connected to the stopper 10 and having a smaller diameter than other portions, the engaging portion 11b and the bite mounting portion 1
It consists of three parts of the conical surface 11c formed between 1a.

A ball holder 12 (holder) having a cylindrical shape and a ring-shaped collar 12a at one end (on the side of the engaging portion 11b) is fitted so as to straddle the bite mounting portion 11a and the engaging portion 11b. ing. As shown in FIG. 2, a plurality of metal balls (steel balls 13 are used in the present embodiment) are radially fitted to the shaft center of the ball holder 12 facing the conical surface 11c. Has been. The steel ball 13 functions as a ball bearing. Further, a spring 14 is externally fitted to the steel shaft 11 in the portion between the stopper 10 and the ball holder 12 in order to constantly urge the ball holder 12 in the direction of the cutting tool 3.

The operation during processing in the configuration shown in FIG. 1 will be described. As described with reference to FIG.
After pressing against (the die in this embodiment) to reduce the outer diameter, the drive shaft 2 having the bite 3 and the self-centering device mounted therein is inserted into the metal tube 1. After that, as described above, the jig 6 is moved to the cutting tool 3 side by the distance L so that the inner surface of the jig 6 faces the blades 3a and 3b, so that the cutting by the cutting tool 3 is performed stably. Then, the drive shaft 2 is rotated while the jig 6 is fixed, and at the same time, the metal tube 1 is moved in the direction of arrow C, and the spiral fin 7 in the direction orthogonal to the axis is continuously formed on the inner wall of the metal tube 1. It is plowed and processed.

During processing, the ball holder 12 is constantly urged by the spring 14, and the steel ball 13 is constantly in contact with the inner surface of the metal tube 1. The initial circumscribed circle diameter is larger than the inner diameter of the tube, but the steel ball 13 was moved to the lower end side of the conical surface 11c while pressing the steel shaft 11 against the spring 14 when inserting it into the metal tube 1. If it is fed into the metal tube 1 in this state, it can be easily inserted into the tube. After insertion,
Each of the steel balls 13 is pressed against the gap between the inner wall surface of the metal tube 1 and the conical surface 11c.

Each of the steel balls 13 is always perpendicular to the tube axis 1
Are in one plane. The axial position thereof is determined by the inner wall surface of the metal tube 1, the spherical surface, the friction coefficient of the conical surface 11c and the pressure received by the steel ball 13, and the conical surface 11c.
It will be in a position where it balances with the reaction force generated in. When the inner diameter of the pipe fluctuates, the rolling surface position of the steel balls 13 fluctuates, the balance is automatically maintained, and the pressure applied to the steel balls located in the opposite direction with respect to the axial center from the inner wall of the pipe increases. As a result,
The frictional force increases, the steel balls 13 are dragged in a narrower direction, and an automatic centering function is generated, so that the change in the cutting depth of the cutting tool 3 is automatically corrected. As a result, the rotary shaft of the cutting tool 3 is maintained in a state of being accurately aligned with the axial center of the metal tube 1 without play.

[Embodiment 2] FIG. 3 is a front sectional view showing another embodiment of the present invention. The present embodiment is intended to deal with the case where the metal pipe 1 to be processed is long. As the metal tube 1 becomes longer, the drive shaft 2 also becomes longer accordingly. If the drive shaft 2 becomes long, the drive shaft 2 may touch and rotate during rotation, and the cutting depth of the cutting tool 3 may fluctuate. To solve this, the drive shaft 2 may be supported at a plurality of points. As one of the means, the automatic alignment mechanism may be multi-staged. This embodiment is embodied in this idea, and has a configuration in which the automatic centering mechanism shown in FIG. 1 is arranged in two stages in cascade. Along with this, the steel shaft 11 is also 2
It has a stepped structure, and the first step has a bite mounting portion 11a and an engaging portion 1
1b, a conical surface 11c, a ball holder 12, a steel ball 13 and a spring 14, and the second stage is a bite mounting portion 11
d, the engaging portion 11e, the conical surface 11f, the ball holder 15, the steel ball 16 and the spring 17. The members in the second stage having the same names as those in the first stage have the same function or the same operation. Therefore, the description of the mechanism and operation is omitted here.

In each of the above-described embodiments, the example in which the cutting tool 3 is used to form the spiral fin is shown, but the present invention is not limited to this, and a metal pipe and this It can be applied to all that performs cutting by relatively rotating the processing tool inserted inside. Further, the processing tool is not limited to the bite. Further, in each of the above-described embodiments, the jig 6 is used to perform processing for changing the outer diameter, but this jig is not always necessary, and processing with a processing tool may be performed without changing the pipe diameter. It is possible. In this case, it is necessary to make the diameter of the cutting tool 3 which is a processing tool larger than the inner diameter of the metal tube 1 (or to provide a means for changing the cutting edge position of the cutting tool in the radial direction of the tube).

Further, in each of the above-mentioned embodiments, the ball holder 12 (or the ball holder 15) is biased by using the spring, but a cylinder mechanism using hydraulic pressure or air pressure, or an electromagnetic solenoid is used. Alternatively, the plunger mechanism or the clutch mechanism may be used. Furthermore, in the embodiment of FIG. 3, the automatic alignment mechanism is provided in two stages, but it is possible to further increase it according to the length of the metal tube.

In addition to the above, in the above-mentioned embodiment, the contact portion between the ball holder 12 and the steel shaft 11 is shown as a plane contact. However, if a point contact structure using a ball bearing or the like is used, the driving can be performed. The shaft 2 can be rotated more smoothly.

[0025]

As described above, according to the present invention, the processing tool mounting portion having the processing tool mounted on the tip thereof, the conical portion formed so as to contact this portion, and the processing so as to contact the conical portion. A shaft body having a small diameter portion is provided, and a cylindrical holder is externally fitted to the shaft body so as to maintain a substantially horizontal state, so that the shaft body is rotatable and is in contact with the conical portion of the shaft body. Since a plurality of metal balls are held by the holding tool and the holding tool is further urged in the processing position direction by the urging means, it is possible to center the processing tool easily and accurately. become.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing an embodiment of an automatic centering device according to the present invention.

FIG. 2 shows a sectional view taken along the line AA of FIG.

FIG. 3 is a front sectional view showing another embodiment of the present invention.

FIG. 4 is a front cross-sectional view showing the configuration of an apparatus for forming a spiral groove on the inner wall of a metal tube.

FIG. 5 is a front cross-sectional view showing a state where the state of FIG. 4 is changed to processing.

6 is a sectional view taken along line AA of FIG.

FIG. 7 is a cross-sectional view showing another conventional configuration of an apparatus for forming a groove on the inner wall of a metal tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal tube 2 Drive shaft 3 Tool 6 Jig 7 Spiral fin 11 Steel shaft 11a, 11d Tool mounting part 11b, 11e Engagement part 11c, 11f Conical surface 12,15 Ball holder 13,16 Steel ball 14,17 spring

Claims (2)

[Claims] 1. An inner surface of a metal pipe, wherein a working tool is inserted into a metal pipe, and the working tool and the metal pipe are relatively rotated and axially relatively moved to process the inner wall of the metal pipe. In the processing device, a large-diameter processing tool mounting portion on which the processing tool is mounted at the tip,
A shaft body having a conical portion formed so as to contact this portion, and a small-diameter portion formed so as to contact the conical portion; and contacting the conical portion of the shaft body and the inner surface of the metal pipe, And a plurality of metal balls that are rotatably arranged, and a tubular holder that holds the metal balls that are externally fitted so as to maintain a substantially horizontal state with respect to the small-diameter portion and the processing tool mounting portion. And an urging means for urging the holder in the processing position direction of the metal pipe, an automatic centering device for a metal pipe inner surface machining device. 2. The shaft body is provided in multiple stages in the axial direction,
The automatic centering device for a metal pipe inner surface processing apparatus according to claim 1, wherein the processing tool, the holding tool provided with the metal balls, and the urging means are provided in each step thereof.