JP2007061889A - Tube expansion tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tube expansion tool capable of shortening tube expansion time by enhancing working efficiency. <P>SOLUTION: The tube expansion tool 1 comprises a plurality of rollers 4 having a tapered shape, a cylindrical frame 3 capable of rotatably holding the plurality of rollers 4 on a concentric circle, and a mandrel 5 which is slidably and rotatably inserted in the frame 3 and has a tapered shape corresponding to the tapered shape of the rollers 4. By making the mandrel 5 be advanced with respect to the frame 3, the tube expansion diameter constituted of circumscribing circles of the plurality of rollers 4 is increased, and a tube TU is expanded while the tube is mounted on a rotation-driving machine and the rollers 4 are rolled. The tube expansion tool has a shank 2 to be connected to the rotation-driving machine. The mandrel 5 is abutted on the front end of the shank 2 and rotatably arranged. The frame 3 is connected to the shank 2 slidably in the longitudinal direction, and integrally rotated with the shank 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tube expansion tool, and more particularly to a tube expansion tool that can shorten the tube expansion time.

In general, in the process of joining and fixing a tube to a tube plate in the manufacturing process of a heat exchanger such as a boiler, a condenser, and a radiator, various tube expansion tools are used to expand the tube from the inner diameter side and press-contact the tube plate. (Patent Document 1, Patent Document 2).
For example, in the tube expansion tool described in Patent Document 1, an operator can easily expand a tube by rotating the roller by connecting the tube expansion tool to a rotary drive and pressing the tube against the inner peripheral surface of the tube. It is configured to be able to. In addition, the expanded portion of the tube forms a smooth continuous surface with a small curvature, and can achieve a finish with a high expanded quality while maintaining a perfect circular shape.

The configuration of the tube expansion tool described in Patent Document 1 will be specifically described with reference to FIG. FIG. 5A is a cross-sectional view for explaining a conventional tube expansion tool, and FIG. 5B is a partial plan view showing a positional relationship between a roller and a mandrel.
As shown in FIG. 5 (a), a tube expanding tool 1 'described in Patent Document 1 includes a tapered taper-shaped mandrel 5' formed integrally with a connecting portion 51 'connected to a rotary drive (not shown). And a plurality of rollers 4 'having reverse tapered shapes corresponding to the tapered shape of the mandrel 5', and a frame 3 'for rotatably holding the plurality of rollers 4' on the outer peripheral surface of the mandrel 5 '. .
In general, the rotary drive machine to which the tube expansion tool 1 'is connected uses a hand-type tube expansion device in which an operator holds the tube in his hand and rotates by detecting the load torque at the time of tube expansion. -It has a controller that controls the stop.

In such a tube expanding tool, as shown in FIG. 5 (a), when the operator advances the mandrel 5 'connected to the rotary drive machine relative to the frame 3', the outside of the mandrel 5 'is gradually increased. Since the large diameter portion abuts on the roller 4 ', the roller 4' is pushed outward from the outer peripheral surface of the frame 3 'and pressed against the inner peripheral surface of the tube TU. In this state, when the mandrel 5 'is rotated forward (rotation in the A direction, right rotation as viewed from the rear of the tool) by the rotary drive, the roller 4' is rotated in the reverse direction (rotation in the R direction, left rotation as viewed from the rear of the tool). ) And revolve clockwise around the mandrel 5 '.
That is, by rotating the mandrel 5 ′ by a rotation driving machine (not shown), the roller 4 ′ is rotated, and the tube TU is rolled from the inner peripheral surface while revolving around the mandrel 5 ′ together with the frame 3 ′. The diameter is increased (this rotation method is called “mandrel rotation type”).

As shown in FIG. 5B, the roller 4 ′ is held by the frame 3 ′ (see FIG. 5A) with a so-called feed angle θ with respect to the mandrel 5 ′. When 4 'rotates in the reverse direction (R direction), the mandrel 5' generates a propulsive force in the forward direction (mandrel self-propulsion function), and the roller 4 'automatically moves with the forward movement of the mandrel 5'. The frame 3 'is pushed out from the outer peripheral surface of the frame 3'.
Japanese Utility Model Publication No. 7-15128 JP-A-7-290171

However, in the conventional mandrel rotating type tube expansion tool 1 ', the mandrel 5' is rotated by the rotation drive machine, the roller 4 'is rotated by the rotation of the mandrel 5', and the roller 4 'is revolved around the mandrel 5'. Since the frame 3 'is rotated while being rotated, the roller 4' performs a so-called planetary motion between the inner peripheral surface of the tube TU and the mandrel 5 '.
Therefore, according to the principle of planetary gear motion, the rotational speed of the frame 3 'is reduced to about 1/3 to 1/5 of the rotational speed of the mandrel 5', depending on the mandrel and roller diameter. Therefore, since the rotation speed of the roller 4 '(frame 3') does not increase, it takes time for the tube expansion work, and there is a problem from the viewpoint of work efficiency.

However, in the mandrel rotating type tube expansion tool 1 ′, when the rotational speed of the rotary drive is increased to increase the rotational speed of the roller 4 ′, vibration occurs and induces vibration. In addition, the burden on the operator increases and becomes a problem from the viewpoint of workability. When the rotational speed of the rotary driving machine is increased, the braking reaction force increases when the rotary driving machine is stopped after the end of the pipe expansion work, resulting in poor workability and handling.
On the other hand, if the feed angle θ is increased to shorten the tube expansion time, the angle at which the rotation axis of the roller 4 ′ intersects the axis of the tube TU increases. It tends to be a concave drum. For this reason, there exists a possibility that a problem may arise in the intensity | strength at the time of joining and fixing tube TU to a tube sheet, and confidentiality.
In addition, if the taper angle of the tapered shape of the mandrel 5 ′ is increased to shorten the tube expansion time, the mandrel 5 ′ must be pushed in as much as the forward stroke of the mandrel 5 ′ decreases, so that the burden on each member Increases, which in turn leads to a shortened life of the tube expansion tool.

  Accordingly, an object of the present invention is to provide a tube expansion tool that can improve the working efficiency and shorten the tube expansion time in order to solve the above-described problems. Another object of the present invention is to provide an easy-to-handle tube expansion tool with improved workability.

  In order to solve the above problems, a tube expansion tool according to the present invention includes a plurality of rollers having a tapered shape with a large diameter on the front side, a cylindrical frame that rotatably holds the plurality of rollers on a concentric circle, A mandrel that is slidably and rotatably inserted into the frame and has a tapered shape with a small diameter on the front side so as to correspond to the tapered shape of the roller, and the mandrel with respect to the frame This is a tube expansion tool that expands the diameter of the tube formed by the circumscribed circles of the plurality of rollers by advancing, and is attached to a rotary drive machine and rolls the roller while rolling the roller. A shank coupled to the rotary drive device, wherein the mandrel is rotatably disposed in contact with a front end portion of the shank, and the frame is in contact with the shank. While being slidably connected in the longitudinal direction, characterized in that it is configured to rotate integrally with the shank.

As described above, the present invention includes a cylindrical frame that rotatably holds a roller having a tapered shape whose front side has a large diameter, and a tapered shape whose front side has a small diameter so as to correspond to the tapered shape of the roller. Since the mandrel is slidably inserted, the mandrel is moved forward relative to the frame, so that the mandrel pushes the roller outward from the outer peripheral surface of the frame to form a circumscribed circle of the roller ( Hereinafter, it is referred to as “tool diameter”).
And since the frame is slidably connected to the shank in the front-rear direction, the mandrel disposed in contact with the front end of the shank is advanced relative to the frame by advancing the shank. Can do.
In addition, since the frame is configured to rotate integrally with the shank, the rotation of the shank is directly transmitted to the frame by connecting the shank to the rotation driving device and rotating the shank. That is, the rotation of the shank is transmitted to the frame without being decelerated, and the frame can be rotated at high speed.
And since the mandrel is rotatably inserted with respect to the frame, when the frame is rotated, the mandrel is rotated via the roller.

In the above-described invention, it is desirable that the mandrel is biased to the front end portion of the shank by the biasing means.
According to such a configuration, at the end of the pipe expanding operation, the tool diameter can be minimized by reliably retracting the mandrel until it abuts against the shank, so that the workability is good and the handling is easy.
Further, by biasing the mandrel to the shank, it is possible to prevent the mandrel from coming off from the frame. For example, it is not necessary to provide a special stopper such as a cap nut at the tip of the mandrel. For this reason, there is no possibility that the cap nut interferes with the tube during the tube expansion operation, so there is no risk of scratching the inner surface of the tube, and the workability is good and the handling is easy.

In the above-described invention, it is desirable to interpose a lubricating member between the mandrel and the front end portion of the shank.
According to this configuration, the frictional resistance due to the rotation difference between the mandrel and the shank generated at the contact portion can be reduced by interposing the lubricating member at the contact portion between the mandrel and the front end portion of the shank.

In the above-described invention, it is preferable that the feed angle is formed so that the rotation axis of the mandrel and the rotation axis of the roller intersect, and the roller is rotatably held on the frame.
According to this configuration, by rotating the roller, in addition to the rotational force component, the forward force component due to the feed angle is generated in the mandrel, and the forward thrust force is applied (mandrel self-propelling function).
For this reason, even if an operator does not advance the shank while holding the rotary drive machine, the mandrel naturally moves forward and expands the tool diameter, so that mandrel operation is unnecessary. Therefore, it is easy to handle the tool and is suitable for automating the pipe expansion work. In addition, by appropriately setting the self-propelling force of the mandrel, the load torque at the time of pipe expansion can be appropriately set without being affected by the force of the operator, so that the pipe expansion quality can be stabilized.
On the other hand, when the diameter of the tube is expanded and the diameter expansion operation is completed, the reverse rotation of the rotary drive machine can apply a thrust in the backward direction to the mandrel. The tool diameter can be reduced by retreating. For this reason, the operator does not need to perform an operation of retracting the mandrel, the handling of the tube expansion tool is easy, and it is suitable for automation of the tube expansion operation.

  According to the tube expansion tool which concerns on this invention, the tube expansion tool which can improve work efficiency and can shorten tube expansion time can be provided. Moreover, according to the pipe expansion tool which concerns on this invention, the easy-to-handle pipe expansion tool which improved workability | operativity can be provided.

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
In the drawings to be referred to, FIG. 1 is a cross-sectional view for explaining the configuration of a tube expanding tool according to an embodiment of the present invention, and FIG. 2 is a view for explaining the positional relationship between a roller and a mandrel. ) Is a plan view, and (b) is a schematic cross-sectional view. FIG. 3 is a cross-sectional view showing a state when the mandrel of the tube expansion tool according to the embodiment of the present invention is advanced, and FIG. 4 is a cross-sectional view taken along the line XX of FIG.

  As shown in FIG. 1, a tube expansion tool 1 according to an embodiment of the present invention includes a shank 2, a cylindrical frame 3 that rotates integrally with the shank 2, and a roller 4 that is rotatably held by the frame 3. A ball roller 6 provided at the front end portion 23 of the shank 2, a mandrel 5 that is slidably and rotatably inserted in contact with the ball roller 6, and a mandrel 5 is attached to the front end portion 23 of the shank 2. A coil spring 8 is provided, and a bearing collar 9 mounted on the outer peripheral surface of the frame 3 is provided.

The shank 2 includes a connecting portion 21 connected to a rotary drive machine (not shown) and a body portion 22 connected to the frame 3.
As an example, the connecting portion 21 adopts a square shape, but may be a tapered shape. It can also be connected to a rotary drive through various attachments.
The body portion 22 has a cylindrical shape slightly larger in diameter than the connecting portion 21, and a bottomed mounting hole 24 for fitting a ball roller 6 to be described later is formed in the front end portion 23. In addition, a key 25 is embedded in the front side of the outer peripheral surface of the body portion 22 so as to rotate integrally with the frame 3 while sliding.

A set collar 26 for restricting the amount of pushing of the shank 2 is attached to the body portion 22 of the shank 2.
As shown in FIG. 1, the set collar 26 is configured so that a screw hole 26 a is formed in the split ring and can be fixed to a predetermined position of the body portion 22 of the shank 2 by tightening a bolt (not shown). With this configuration, by adjusting the mounting position of the set collar 26, when the shank 2 is pushed into the frame 3, the stroke S until the set collar 26 comes into contact with a frame nut 38 to be described later is set. The maximum push amount of 2 is regulated.

The frame 3 is formed in a stepped cylindrical shape having a reduced diameter part 34 on the front side and an enlarged diameter part 35 on the rear side. A roller 4 is held in the reduced diameter portion 34 of the frame 3 so as to protrude from the outer peripheral surface of the frame 3 and rotate freely. Further, a screw portion 31 and a flat portion 32 for mounting and fixing a bearing collar 9 which will be described later are provided on the outer peripheral surface of the front portion of the enlarged diameter portion 35 located behind the roller 4.
At the rear part of the frame 3, a male screw 37 is formed at the edge of the outer peripheral surface, and a cap-shaped frame nut 38 having a function of preventing the shank 2 from being detached is screwed over the shank 2.
A key groove 33 is formed on the inner peripheral surface of the rear portion of the frame 3, and the key 25 of the shank 2 is fitted into the key groove 33. With this configuration, the shank 2 slides in the front-rear direction along the key groove 33 with respect to the frame 3, and the shank 2 and the frame 3 rotate as a unit.
As will be described later, a coil spring 8 as a biasing means for biasing the mandrel 5 toward the shank 2 is mounted on the inner peripheral surface of the enlarged diameter portion 35 of the frame 3.

As shown in FIG. 1, the roller 4 has a tapered shape with a large diameter on the front side and a small diameter on the rear side (see FIG. 2B), and a large R chamfer 41 (see FIG. 2A) )) Is formed.
Further, as shown in FIG. 2A, the rotation axis of the roller 4 and the rotation axis of the mandrel 5 are arranged so as to form a predetermined feed angle θ. The feed angle θ is set so that the mandrel 5 moves forward when the shank 2 (see FIG. 1) is rotated forward (rotation in the direction A), and the angle is appropriately determined in consideration of the load torque required for pipe expansion. Is set.
As shown in FIG. 4, the rollers 4 are arranged in three equal circles on the circumference of the frame 3 and are rotatably held, and the expanded diameter (tool diameter φD) formed by the circumscribed circle of the three rollers is set. The central axis of the roller 4 is disposed so that the front side is inclined toward the center so that the axial direction of the roller 4 is the same (see FIG. 2B).
In this embodiment, as an example, the rollers 4 are arranged in three equal positions on the circumference of the frame 3, but the present invention is not limited to this, and depends on conditions such as the diameter and strength of the tube TU. The number and sequence are determined as appropriate.

As shown in FIG. 1, the mandrel 5 is formed in a columnar shape and is slidably and rotatably inserted into the frame 3. The front surface of the mandrel 5 is in contact with the roller 4 at the outer peripheral surface (see also FIG. 4), and the rear end surface is in contact with the front end portion 23 of the shank 2 with the ball roller 6 interposed therebetween.
Specifically, the front portion of the mandrel 5 has a tapered shape in which the front side corresponding to the tapered shape of the roller 4 has a small diameter and the rear side has a large diameter. That is, the taper shape formed by the outer peripheral surface of the mandrel 5 and the taper shape formed by the inscribed circles of the three rollers 4 are configured so that the mandrel 5 is inserted into the frame 3. . With this configuration, the front side of the mandrel 5 is held by the frame 3 via the roller 4.
On the other hand, the outer peripheral surface of the rear part of the mandrel 5 has a cylindrical shape having an outer diameter equal to the axial direction, not a tapered shape, and a rear thrust bearing 13 to be described later is mounted on the outer peripheral surface. With this configuration, the outer peripheral surface on the rear side of the mandrel 5 is held by the frame 3 via the thrust bearing 13. Further, a conical recess 51 for engaging the ball roller 6 is provided on the rear end face of the mandrel 5 so as to perform an alignment function for supporting the shank 2 and the mandrel 5 coaxially. Yes.
The mandrel 5 is heat-treated or surface-treated to improve sliding characteristics and durability.

The mandrel 5 is urged to the front end 23 of the shank 2 via the ball roller 6 by a coil spring 8 as urging means.
Specifically, the front thrust bearing 12 is disposed on the side wall 36 formed in the enlarged diameter portion 35 on the inner peripheral surface of the frame 3, and is locked to the rear portion of the outer peripheral surface of the mandrel 5 by the retaining ring 14. A rear thrust bearing 13 is disposed, and a coil spring 8 is mounted between the two thrust bearings 12 and 13. For this reason, the urging force that the coil spring 8 tends to extend acts on the mandrel 5 in the direction of the shank 2, and the mandrel 5 is urged in the direction of the shank 2. The urging force of the coil spring 8 is appropriately set in consideration of the mandrel 5 moving toward the shank 2 and being stably held, that is, taking into account the weight of the mandrel 5.
In the present embodiment, the thrust bearings 12 and 13 are used as an example. However, the present invention is not limited to this, and a sliding member such as a thrust ring can be appropriately applied according to the use conditions. . Further, the outer peripheral surface of the rear part of the mandrel 5 can be directly fitted and guided to the inner peripheral surface of the frame 3 without interposing a sliding member.

As shown in FIG. 1, the bearing collar 9 is provided on the outer peripheral surface of the enlarged diameter portion 35 located behind the roller 4 held by the frame 3, and includes a rotation-side collar rear wheel 91 and a fixed-side collar front wheel. 92 and a ball bearing 93 interposed between the two.
The collar rear wheel 91 is formed in a cylindrical shape having a flange 91a. An internal thread is formed on the inner peripheral surface of the collar rear wheel 91 and is screwed into the thread portion 31 on the outer peripheral surface of the frame 3 with the flange 91a on the front side, and is fixed to the outer peripheral surface of the frame 3 with a set screw 91b. . On the other hand, the collar front wheel 92 is formed in a stepped cylindrical shape, and has a stepped bottom 92a on the inner peripheral surface.
Then, the collar front wheel 92 is connected to the flange 91a of the collar rear wheel 91 so that the flange 91a of the collar rear wheel 91 and the bottom 92a of the collar front wheel 92 face each other, and the retaining ring 94 prevents the collar 91 from coming off. Yes.
The ball bearing 93 is inserted between the bottom portion 92 a of the collar front wheel 92 and the flange 91 a of the collar rear wheel 91 that face each other, and the rotational force of the collar rear wheel 91 that rotates integrally with the frame 3 is not transmitted to the collar front wheel 92. It is configured as follows. With such a configuration, the end surface 92b of the collar front wheel 92 is brought into contact with the end surface of the tube TU to perform the tube expansion operation, thereby appropriately setting the effective length and reach of the roller, and the length of the tube expansion portion EX (see FIG. 3). Can be adjusted.

Subsequently, the operation of the pipe expanding tool according to the embodiment of the present invention will be described with reference to FIGS.
The tube expansion tool 1 according to the embodiment of the present invention performs tube expansion work while rotating the shank 2 by connecting the connecting portion 21 of the shank 2 to a rotary drive machine (not shown). Note that there are various types of rotary drive machines such as an electric type and a hydraulic drive type depending on applications, and the rotation / stop can be controlled by detecting the load torque at the time of pipe expansion.

As shown in FIG. 1, the operator retreats the shank 2 most with respect to the frame 3 (the tool diameter φD is minimum, FIG. As shown in b), the tube expansion tool 1 is inserted into the tube TU and moved forward until the end surface 92b of the collar front wheel 92 comes into contact with the end surface 92b of the collar front wheel 92 while rotating forward (A direction).
The rotary drive machine may be moved forward until the end face 92b of the collar front wheel 92 comes into contact with the end face 92b of the tube TU, and then the rotary drive machine may be rotated forward. It may be brought into contact with the end face of the TU or may be simultaneous.

Then, after the end surface 92b of the collar front wheel 92 comes into contact with the end surface of the tube TU, the forward movement of the frame 3 is restricted. Therefore, when the operator further advances the rotary drive machine, the shank 2 moves relative to the frame 3. Pushed in. For this reason, the mandrel 5 that is in contact with the front end 23 of the shank 2 via the ball roller 6 also moves forward relative to the frame 3.
In this state, the shank 2 is in contact with the mandrel 5 while rotating, but the frictional resistance due to the rotation of the shank 2 is reduced by the ball roller 6 interposed between the shank 2 and the mandrel 5.
Further, when the shank 2 rotates, the frame 3 integrally coupled through the key 25 embedded in the shank 2 also rotates. At this time, the bearing collar 9 mounted on the outer peripheral surface of the frame 3 rotates with the collar rear wheel 91 integrally with the frame 3, but since the ball bearing 93 is interposed, the collar front wheel 92 is made of the tube TU. The rotation is stopped in contact with the end face.

  When the operator advances the shank 2 and pushes the mandrel 5 in the forward direction, the tapered portion having a large outer diameter formed on the front portion of the mandrel 5 gradually contacts the roller 4, and the roller 4 And the tool diameter φD (see FIG. 2B) is expanded. In this way, the tool diameter φD is increased, and eventually the roller 4 comes into contact with the inner peripheral surface of the tube TU and presses the inner peripheral surface of the tube TU. Then, due to the reaction, the roller 4 and the mandrel 5 are pressed against each other, and the mandrel 5 follows the roller 4 and rotates.

  That is, as shown in FIG. 4, when the frame 3 is rotated forward (rotated in the direction A) integrally with the shank 2 (see FIG. 1), the roller 4 rotates clockwise along the inner peripheral surface of the tube TU ( The mandrel 5 rotates to the right (rotates in the A direction) because it rotates to the left (rotates in the R direction) while rolling in the A direction).

  Here, looking at the relationship between the rotation axis of the roller 4 and the rotation axis of the mandrel 5, as shown in FIG. 2 (a), the roller 4 and the mandrel 5 form a feed angle θ and rotate both. The axes are arranged to cross each other. Therefore, the rotational force F of the roller 4 generates the forward thrust F2 of the mandrel 5 in addition to the rotational force F1 of the mandrel 5. For this reason, the mandrel 5 is moved forward by being given forward thrust by the roller 4 (mandrel self-propelling force), and as the mandrel 5 moves forward, the roller 4 is further pushed outward and the tool diameter φD (see FIG. 2 (b)) is expanded, and the tube TU expansion operation proceeds.

Therefore, as long as the operator holds the rotary drive during the tube expansion operation, the mandrel 5 is automatically advanced by the self-propelling force of the mandrel 5 as shown in FIG. Tube expansion work proceeds. That is, the operator pushes the shank 2 until the tool diameter φD (see FIG. 2B) is increased, the roller 4 and the mandrel 5 are pressed, and the self-propulsive force of the mandrel 5 is generated. Thereafter, the tube expansion work automatically proceeds by the self-propulsion force of the mandrel 5.
Of course, during tube expansion work, the operator always pushes the rotary drive machine to the tube TU side in many cases, so that the shank 2 moves forward as the mandrel 5 moves forward. Is much smaller than the self-propelling force of the mandrel 5 and is normally negligible. Therefore, the load torque at the time of tube expansion is determined by the self-propelling force of the mandrel 5. When the operator pushes the shank 2 too much, the set collar 26 regulates the push amount S of the shank 2 (see FIG. 1).

As the tool diameter φD is increased in this way, the load torque at the time of pipe expansion gradually increases, and the controller is controlled so that the rotation of the spindle of the rotary drive stops when a preset threshold value is reached. ing.
Therefore, when the tube TU is expanded to a predetermined diameter, the maximum load torque is detected and the rotary driving machine automatically stops. Since the roller 4 and the tube TU are pressed when the rotary drive is stopped, it is necessary to reduce the tool diameter φD and open the tube TU.

In order to reduce the tool diameter φD, the rotary driving machine is reversely rotated to perform an operation opposite to the diameter expanding operation. When the rotary drive is rotated in the reverse direction, the frame 3 is rotated in the reverse direction via the shank 2. Therefore, the mandrel 5 is automatically retracted by the reverse operation to the above-described operation, and the roller 4 is moved from the outer peripheral surface of the frame 3. It is buried and the tool diameter φD (see FIG. 2B) is reduced.
When the tool diameter φD is reduced and the roller 4 moves away from the inner peripheral surface of the tube TU, the mandrel 5 is reliably retracted by the biasing force of the coil spring 8 until it abuts against the shank 2, and the tool diameter φD is minimized. Become. In this way, when the tool diameter φD is minimized, the operator stops the rotary drive machine, extracts the tube expansion tool 1 from the tube TU, and ends the tube expansion operation.

Since the tube expansion tool 1 according to the embodiment of the present invention operates as described above, the following effects are produced.
In the tube expansion tool 1, since the frame 3 rotates integrally with the shank 2, the number of rotations of the frame 3 and the rotation number of the rotary drive machine are the same, and the roller 4 is compared with the conventional tube expansion tool 1 '(see FIG. 5). Can be rotated at high speed. Therefore, according to the tube expansion tool 1, work efficiency can be improved and tube expansion time can be shortened. Further, since the frame 3 is directly rotated, even if the frame 3 is rotated at a high speed, vibration is hardly generated, the burden on the operator is reduced, and safety can be improved.

  In this regard, in the conventional tube expanding tool 1 ', the mandrel 5' is rotated by the rotation drive machine, the roller 4 'is rotated by the rotation of the mandrel 5', and the roller 4 'is rotated by the rotation of the roller 4'. Since the frame 3 'is rotated by revolving around, the frame 3' performs a so-called planetary motion. For this reason, the rotational speed of the frame 3 'is reduced to about 1/3 to 1/5 of the rotational speed of the mandrel 5' due to the principle of planetary gear motion, and the tube expansion time increases accordingly.

Table 1 shows a comparison of the expansion speed and the expansion time between the tube expansion tool 1 according to the present embodiment and the conventional tube expansion tool 1 ′ (see FIG. 5). As shown in Table 1, in the conventional mandrel rotary tube expansion tool 1 ′, the rotational speed of the rotary drive machine is equal to the rotational speed of the mandrel 5 ′ and is 820 min ⁻¹ , whereas the frame rotation according to this embodiment is performed. In the tube expansion tool 1 of the type, the rotation speed of the rotary drive machine is equal to the rotation speed 820 min ⁻¹ of the frame 3. For this reason, in the conventional mandrel rotation type tube expansion tool 1 ′, the rotation speed of the frame 3 ′ is 210 min ⁻¹ , which is reduced to about ¼ compared with the frame rotation type tube expansion tool 1 according to the present embodiment. Yes.
Therefore, when the tube TU has an outer diameter of 25.4 mm and a wall thickness of 2 mm and is mounted on the same rotary drive machine, the tube rotation type tube expansion tool 1 according to this embodiment performs the conventional mandrel rotation. Compared with the tube expansion tool 1 'of the formula, the tube expansion time was shortened to about 1 / 3.89.
Table 1 shows a proportional conversion of the conventional mandrel rotary tube expansion tool 1 'with the tube expansion time of the frame rotation tube expansion tool 1 according to the present embodiment as 1 second. The tube expansion time in the frame rotation type tube expansion tool 1 according to the embodiment was actually about 1 second.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be implemented with appropriate modifications.
For example, in the present embodiment, the frame 3 and the mandrel 5 are coupled with the key 25 and are configured to rotate together while being slidable. However, the present invention is not limited to this. Can also be configured. It is also possible to form a long hole in one of the frame 3 or the mandrel 5 and provide a pin in the other so that the pin can be fitted into the long hole and rotated as a unit while being slidable. is there.

  In this embodiment, the coil spring 8 is used as the biasing means for biasing the mandrel 5 to the shank 2, but the present invention is not limited to this, and a torsion spring, a disc spring, or the like may be used. Various springs may be combined. Further, an elastic member such as rubber may be used, or a fluid pressure such as air or hydraulic pressure may be used.

In the present embodiment, the ball roller 6 is interposed as a lubrication member between the mandrel 5 and the shank 2, and the mandrel 5 and the front end 23 of the shank 2 are indirectly brought into contact with each other. The mandrel 5 and the shank 2 may be brought into direct contact with each other without the ball roller 6 interposed therebetween. When the mandrel 5 and the shank 2 are caused to directly contact and slide, the sliding characteristics of the sliding surface can be improved by heat treatment or coating. Further, instead of the ball roller 6, a rolling bearing such as a thrust bearing or a sliding bearing such as a thrust ring may be interposed.
In the present embodiment, the bearing collar 9 and the set collar 26 are mounted. However, the bearing collar 9 and the set collar 26 may be mounted according to the application, and the present invention is not limited to this. For example, when the fin tube of an air conditioner or the like is expanded over the entire length, it is possible to expand the tube 3 while advancing the frame 3 using the self-propulsion function without attaching the bearing collar 9.

It is sectional drawing for demonstrating the structure of the pipe expansion tool which concerns on embodiment of this invention. It is a figure for demonstrating the positional relationship of the roller and mandrel in the pipe expansion tool which concerns on embodiment of this invention, (a) is a top view, (b) is sectional drawing shown typically. It is sectional drawing which shows a mode when the mandrel in the pipe expansion tool which concerns on embodiment of this invention advances. It is sectional drawing of the XX line of FIG. 3 which shows the arrangement | sequence of the roller in the pipe expansion tool which concerns on embodiment of this invention. It is a figure for demonstrating the structure of the conventional pipe expansion tool, (a) is sectional drawing, (b) is a fragmentary top view which shows the positional relationship of a roller and a mandrel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tube expansion tool 2 Shank 21 Connection part 22 Body part 23 Front end part 25 Key 26 Set collar 3 Frame 33 Keyway 4 Roller 5 Mandrel 6 Ball roller (lubricating member)
8 Coil spring (biasing means)
9 Bearing collar EX Expanded part S Stroke TU tube φD Tool diameter (expanded pipe diameter)
θ Feed angle

Claims (4)

A plurality of rollers having a tapered shape with a large front side;
A cylindrical frame that rotatably holds the plurality of rollers on a concentric circle;
A mandrel having a tapered shape that is slidably and rotatably inserted into the frame and has a small diameter on the front side so as to correspond to the tapered shape of the roller;
By advancing the mandrel with respect to the frame, the diameter of the expanded pipe formed by the circumscribed circle of the plurality of rollers is increased, and
A tube expansion tool that is attached to a rotary drive and rolls the roller while expanding the tube,
Comprising a shank coupled to the rotary drive;
The mandrel is disposed in contact with the front end of the shank;
The tube expansion tool according to claim 1, wherein the frame is slidably connected to the shank in the front-rear direction and is configured to rotate integrally with the shank.   The tube expansion tool according to claim 1, wherein the mandrel is urged to a front end portion of the shank by an urging means.   The tube expansion tool according to claim 1 or 2, wherein a lubricating member is interposed between the mandrel and the front end of the shank.   The feed roller is formed so that the rotating shaft of the mandrel and the rotating shaft of the roller intersect each other, and the roller is held. Tube expansion tool.

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