JP2882231B2 - Pipe bar bending equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tube rod bending apparatus for bending a tube rod to an arbitrary radius and angle without using a bending die.

[0002]

2. Description of the Related Art Tube rod bending apparatuses are roughly classified into die-type apparatuses using bending dies and dieless apparatuses using no bending dies. Untyped device is often markedly reduced equipment costs compared with the mold has devices also need to stock several kinds costly bending tool is universal type can be selected arbitrarily bending radius and bending angle be able to. However, when performing high-precision processing, a mold-type apparatus is used. In other words, high-precision bending was impossible unless a bending die was used.

A problem that occurs when a bending die is not used will be described with reference to a bending apparatus disclosed in Japanese Patent Application Laid-Open No. 50-29465.

In the bending apparatus disclosed in the above publication, FIG.
As shown in FIG.
The constraining roll 31 is provided, and the turning arm 30 is driven by sandwiching the material to be bent 33 between the constraining roll 31 and the second constraining roll 32 attached to the tip of the turning arm 30. With the rotation of the swivel arm 30, the second restraining roll 3
2 revolves around the first constraining roll 31, and the constraining rolls 31 and 32 rotate at a predetermined peripheral speed ratio in a direction in which the to-be-bent material 33 is sent to the rear end side. To a bending radius of.

[0005]

This bending apparatus is based on the premise that slip does not occur between the restraining rolls 31, 32 and the material 33 to be bent.
In fact, this slip cannot be avoided. Therefore, the revolving angle of the constraining roll 32 shifts, and an error occurs in the bending radius and the bending angle. When the material to be bent 33 is a tube, the axis l ₁ of the unbent portion is an axis l perpendicular to the revolving arm 30.
₂ and the contact point between the constraining roll 31 and the constraining roll 32 of the material to be bent 33 is displaced from the axis of the turning arm 30, and the bending process is performed while crushing the material to be bent 33. Therefore, it is unavoidable to make the bent material 33 elliptical. Therefore, as described at the beginning, a bending device that does not use a bending die cannot perform high-precision bending.

An object of the present invention is to provide a tube rod bending apparatus which can perform high-precision bending processing without using a bending die.

[0007]

SUMMARY OF THE INVENTION According to the present invention, there is provided a tube rod bending apparatus for bending a tube rod without using a bending die.
The bending device, wherein the bending target material is clamped by a chuck provided at a tip side of a rotation axis, and the rotation axis is centered.
With bending to be bent member by being forcibly rotated at a predetermined speed as said rotary shaft so as to change the bending radius is the bending material before bending is positioned
Move on a line perpendicular to the pass line, and
A swivel arm that changes the distance to the ramp, and has a hole corresponding to the outer surface shape on the outer peripheral surface that supports the bendable material and is located inside the bendable material that is bent by the swivel arm.
In addition, the inner restraining roll whose rotation center is located on the line, and the outer side of the material to be bent which is bent by the revolving arm.
To support the material to be bent in the pass line, and
Outside with a hole shape on the outer peripheral surface corresponding to the outer shape of the bent material
And the rear end of the material to be bent disposed in the pass line is clamped, and the material to be bent is translated in the direction in which the material to be moved moves along the path line during bending. A carriage for applying a controlled axial tensile or compressive force to the material being bent by controlling the translational drive speed with respect to the rotational drive speed of the revolving arm. .

[0008]

According to the tube rod bending apparatus of the present invention, the turning arm is
It is driven to rotate at a predetermined speed and
By controlling the translation drive speed of the carriage, an arbitrary tensile force or compressive force in the axial direction can be applied to the material to be bent during bending. Therefore, an axial stress (tensile or compressive) is generated in the material to be bent during the bending, and the bending can be performed with a small bending moment, so that the flatness caused by the bending itself can be reduced.

When an axial tensile force is applied to the material to be bent during bending, the contact portion of the material to be bent with the inner constraining roll is further strongly pressed by the constraining roll, and the hole of the constraining roll is pressed. As a result, the contact portion is prevented from rising from the mold, so that the hole shape prevents elliptical formation. On the other hand, when a compressive force is applied, the pressing force against the constraining roll inside the material to be bent is weakened, and the elliptic prevention effect by the hole shape is reduced. Can be prevented from being reduced in thickness.

Further, the bending of the material to be bent is performed not by the roll but by the chuck, so that the slip of the material to be bent can be eliminated. Therefore, the bending radius and the bending angle are also accurate.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a plan view showing an example of the bending apparatus of the present invention, FIG. 2 is a view taken along line AA of FIG. 1, FIG. 3 is a view taken along line BB of FIG. 1, and FIG. FIG. 5 is a view taken on line C of FIG.
FIG.

This bending apparatus bends a pipe bar set on a horizontal pass line using a horizontal swivel arm 1. The swivel arm 1 is slidably supported on a rotary table 2 in the longitudinal direction, and is fixed to an arbitrary slide position by bolts 3, 3. The rotary table 2 has a vertical output shaft 4 of a variable speed reducer 4 (hereinafter simply referred to as a speed reducer 4).
Rotated by a. The speed reducer 4 is driven by a belt 6 using a motor 5 as a power source. When the rotary table 2 rotates, the turning arm 1 rotates about the rotation axis. Therefore, the output shaft 4a of the speed reducer 4 becomes the rotation shaft of the turning arm 1. Also, the state perpendicular to the pass line is the initial position of the turning arm 1, in which the tip of the turning arm 1 intersects the pass line. The rotation angle of the swing arm 1 from the initial position is detected by a pulse encoder 10 attached to the input shaft of the speed reducer 4.

A speed reducer 4 and a motor 5 for driving the turning arm 1 are mounted on a slide table 7. The slide base 7 is movable on a fixed base 8 in a direction perpendicular to the pass line, and is fixed to an arbitrary moving position by bolts 9, 9. By moving the slide table 7, the output shaft 4a of the speed reducer 4, which is the rotation axis thereof, moves in the longitudinal direction of the turning arm 1 without moving the turning arm 1 in the longitudinal direction, and the turning radius of the turning arm 1 is adjusted. Is done. The rotary table 2 is provided with a scale 11 for measuring the relative position between the swivel arm 1 and the rotary table 2, and the fixed base 8 is a scale for measuring the relative position between the slide base 7 and the fixed base 8. 12 are attached.

A chuck 13 for clamping a material to be bent is attached to the tip of the swing arm 1. The chuck 13 is located in the pass line with the turning arm 1 stopped at the initial position. The chuck 13 is a half-split type which is divided in the longitudinal direction of the revolving arm 1 and is united by bolts, and a hole corresponding to the outer shape of the material to be bent is provided on the opposing surface. . The material to be bent set on the pass line is clamped by the chuck 13, and the turning arm 1 is rotated in this state, so that it is bent toward the center of the turning arm 1 while moving toward the distal end.

A restraining roll 14 for restraining the material to be bent from the inside is provided inside the pass line. The restraining roll 14 is a non-driven free roller,
Its center is located on a line (reference line) perpendicular to the pass line passing through the center of rotation of the swivel arm 1 and is fixed on the fixed base 8. On the outer peripheral surface of the constraining roll 14, a hole corresponding to the outer shape of the material to be bent is provided over the entire circumference. Outside the pass line, two restraining rolls 15 and 16 for restraining the material to be bent from the outside are provided along the pass line. The constraining rolls 15 and 16 are also free rollers, each center of which is located downstream of the reference line in the material moving direction, that is, on the rear end side of the material to be bent, and is fixed on the fixed base 8. Similar to the inner constraining roll 14, a hole shape corresponding to the outer surface shape of the material to be bent is provided on the outer peripheral surfaces of the constraining rolls 15, 16 over the entire circumference.

The tip of the revolving arm 1 and the chuck 13
Are deflected downstream of the reference line to avoid interference with the restraining rolls 14, 15 and 16.

A carriage 17 is provided upstream of the constraining rolls 14, 15 and 16. Carriage 1
Reference numeral 7 denotes a vertically divided chuck 17a which clamps the rear end of the material to be bent in the pass line. Chuck 1
7a is mounted on the chuck base 17b. The chuck base 17b is guided by a linear way 18 provided immediately below the pass line and freely moves in the pass line direction, and is connected to the female screw member 17d via a connecting member 17c. The female screw member 17d is externally fitted to a male screw feed shaft 19 provided along the pass line. Feed shaft 1
9 is driven to rotate in both forward and reverse directions by a belt 21 using a variable speed motor 20 provided on the fixed base 8 as a power source. As a result, the carriage 17 moves forward and backward in the pass line direction, and is driven to translate with respect to the material to be bent during the bending by the advance.

The translation speed of the carriage 17 is variable,
It is controlled by a control device (not shown). Carriage 1
The pulse encoder 22 is connected to the tip of the feed shaft 19 in order to detect the translation speed 7. Further, in order to detect the axial stress applied to the material to be bent during the bending process, a load cell is interposed in the mounting portion of the chuck 13 and the mounting portion of the chuck 17a in the carriage 17.

Resins such as MC nylon are sufficient materials for the chucks 13 and 17 in terms of holding power, strength, durability and the like.

Next, the operation procedure and operation of the bending apparatus will be described.

The bolts 3, 3 and 9, 9 are loosened so that the swing arm 1 and the slide base 7 can be moved. With the revolving arm 1 fixed at the initial position and the chuck 13 fixed in the pass line, only the slide table 7 is moved. Thereby, the reduction gear 4 which is the rotation axis of the swing arm 1
Is moved in a direction perpendicular to the pass line, and the turning radius of the swing arm 1 is adjusted.

Swivel arm 1 according to the bending radius of the material to be bent
Are adjusted, the bolts 3, 3 and 9, 9
To fix the turning arm 1 and the slide table 7.
Chuck 1 in chuck 13 and carriage 17
In the state where 7a is opened, the material to be bent is passed from the rear end to between the inner restraining roll 14 and the outer restraining rolls 15 and 16, and the bent material is passed until the bending start point coincides with the reference line. Insert into line. The chuck 13 is closed to clamp the vicinity of the bending start point of the material to be bent, and the rear end is clamped by the chuck 17a.

When the setting of the material to be bent is completed, the motor 5 is operated to rotate the turning arm 1 forward. By the rotation of the turning arm 1, the chuck 13 turns and the material to be bent is bent inward while moving forward. The turning speed of the chuck 13, that is, the peripheral speed of the turning arm 1 is
It is obtained from the rotation angle of the swing arm 1 measured by the pulse encoder 10. The inner constraining roll 14 supports the material to be bent from the inside, and its hole shape suppresses the bending of the material to be bent. Outer restraining rolls 15, 16
Guides the material to be bent and makes it enter at right angles to the reference line.

When the material to be bent is bent, the variable speed motor 20 is operated to translate and drive the carriage 17 in the moving direction of the material to be bent. The translation speed of the carriage 17 is slower and faster than the peripheral speed of the revolving arm 1 to apply an axial tensile force or a compressive force to the material to be bent during bending.

FIG. 8 is a stress distribution diagram for explaining the reason why the tensile force and the compressive force contribute to the suppression of flattening.
Shows the case of bending only, (b) shows the case of bending + tension, and (C) shows the case of bending + compression.

In the case of bending only, the stress due to the bending moment has a distribution of tension on the outer side and a distribution of compression on the inner side. The absolute values are equal and the maximum values are at the outer surface and the inner surface.
When this stress exceeds the yield stress σy, it elongates at the outer part,
Since the plastic deformation occurs on both the inside and the outside such that the inside part shrinks, the flatness caused by bending is large. The bending moment Ma at this time is Ma = Z · σy, where Z is the section modulus of the material to be bent.

In the case of bending + tensile, since a tensile force Ft is applied, a tensile stress .sigma.t acts, and when a bending moment is applied, the stress on the outer surface reaches a maximum value. When this stress exceeds the yield stress σy, plastic deformation (elongation) starts on the outside, but the inside is within the elastic range. The bending moment Mb at this time is represented by Mb =
Z (σy−σt).

In the case of bending + compression, since compression Mc is applied, a compression stress σc is acting, and when a bending moment is applied, the stress on the inner surface reaches a maximum value. When this stress exceeds the yield stress σy, plastic deformation (shrinkage) starts on the inside, but the outside is within the elastic range. The bending moment Mc at this time is Mb = Z, where Z is the section modulus of the material to be bent.
(Σy-σc).

FIGS. 8A and 8B in which an axial stress exists.
In the case of, bending moments Mb and Mc at which plastic deformation starts
Is smaller than the bending moment Ma in the case of FIG. 8A where no axial stress exists. As described above, when the bending moment is small, the stress difference between the outside and the inside becomes small, and the bending is performed in a state where either the outside or the inside is within the elastic range, and the bending itself is performed. The degree of flattening caused by this is small.

Therefore, when the translation speed of the carriage 17 is made lower than the peripheral speed of the revolving arm 1 and an axial tensile force is applied to the material to be bent during bending, the degree of flatness caused by the bending itself becomes smaller. . Moreover, since the material to be bent is strongly pushed into the hole shape of the inner restraining roll 14,
Ovalization of the material to be bent is reliably prevented by the hole shape of the constraint roll 14.

On the other hand, if the translation speed of the carriage 17 is made higher than the peripheral speed of the revolving arm 1 and an axial compressive force is applied to the material to be bent during bending, the flatness caused by the bending itself is small. In addition, the material to be bent floats up from the bottom of the groove of the constraining roll 14 on the inner side, and the ovalization preventing effect by the hole shape of the constraining roll 14 decreases. However, since bending is performed by compressive deformation inside the bend, when the material to be bent is a pipe, a decrease in the outside thickness is prevented.

As described above, depending on whether priority is given to prevention of ellipticality or to prevention of wall thinning outside the bending of the pipe,
The translation speed of the carriage 17 with respect to the peripheral speed of the turning arm 1 is determined to be slow.

Further, since the material to be bent is clamped by the chuck 13 and the slip between the material to be bent and the chuck 13 can be eliminated, no error occurs in the bending radius and the bending angle.

When the material to be bent is bent to a predetermined radius and angle, the rotation of the swing arm 1 and the carriage 17
Is stopped, and the chuck 13a of the carriage 13 and the chuck 13 are released. Then, the unprocessed portion of the material to be bent is drawn out of the pass line through the constraining roll 14 and the constraining rolls 15 and 16.

Since the rotation speed, the rotation radius and the rotation angle of the revolving arm 1 can be arbitrarily adjusted, it is possible to perform bending at different bending radii and bending angles at required speeds.

In order to increase the bending accuracy, the swing arm 1
The rotation axis moves on a reference line perpendicular to the pass line
The bending radius is changed by the
Is located on this reference line. The outer diameter of the inner constraining roll 14 is preferably as large as possible within a range of less than twice the minimum bending radius in order to increase the contact surface with the material to be bent and enhance its flattening prevention effect.

In order to enhance the guiding effect on the material to be bent, a plurality of the outer constraining rolls 15 and 16 are preferably arranged along the pass line as shown in the figure and close to the reference line. Although there is no particular geometrical constraint on the outer constraining rolls 15 and 16, as described above, since the guide effect is enhanced by bringing the center of the downstream constraining roll 15 closer to the reference line, the outer diameter is extremely large. You should avoid doing it.
When the center of the constraining roll 15 departs from the reference line, the bent material bends at this portion.

As shown in FIG. 6, the hole shape of the constraining rolls 14, 15, and 16 accommodates the material to be bent in a rolled shape so as to more effectively suppress the flattening of the material to be bent. It is better to have the above depth.

Next, test results of the present bending apparatus will be described.
Table 1 shows the specifications and test conditions of the test apparatus.

[0040]

[Table 1]

The material to be bent is a high precision tube used for a steam generator tube of a pressurized water reactor. The diameter of the hole shape in the constraining roll is slightly larger than the outer diameter of the material to be bent. The translation speed of the carriage is the peripheral speed of the swing arm 47, 1 m
47.1 to 46.1 m below the same for m / sec (constant)
m / sec. As a result, the feed amount of the carriage becomes 0 to 20 from the operating circumference of the turning arm of 1600 mm (constant).
mm. After bending was investigated outer diameter D ₁ of the major axis direction of the bent portion shown in FIG. 6, the outer diameter D ₂ of the minor axis, and the ellipse amount (D ₁ -D _2). FIG. 7 shows the result.

An elliptical amount of 0.2 mm is inevitable due to the diameter of the groove in the constraining roll being larger than the outer diameter of the material to be bent. That is, in the case of the present test apparatus, 0.2 mm is the limit of the ovalization.

When the feed amount of the carriage is equal to the working circumference of the swing arm, that is, when the translation speed of the carriage and the circumferential speed of the swing arm are the same and no tensile force is applied to the material to be bent, Due to the large bending moment and the fact that the material to be bent during the bending process lifts up from the groove bottom of the inner constraining roll, an elliptical amount of 0.4 mm, which is much larger than the regulation limit, was generated.

When an axial tensile force is applied to the material to be bent by making the feed amount of the carriage smaller than the working circumference of the revolving arm, elliptical bending of the bent portion is suppressed, and the feed amount and the working circumference are reduced. When the difference in tension is 5 mm, the difference is slightly less than 0.3 mm and 1
At 0 mm or more, the elliptical amount was reduced to the regulation limit of 0.2 mm, and at 10 mm or more, the roundness required for the required specifications of the steam generator tube was secured.

The steam generator tube has a bending radius of 4
34 types of U-shaped bending from 46.18 mm to 1520.00 mm are required, but by using this bending apparatus, all bending can be performed without requiring replacement of parts.

In the above test example, a tensile force is applied to the material to be bent. However, even if a compressive force is applied, the ellipticity of the material to be bent can be suppressed as compared with a case where no tensile or compressive force is applied. It is possible to reduce the thickness reduction outside the bending.

[0047]

As is apparent from the above description, the bending apparatus for a tube rod according to the present invention does not use a bending die, but can change the bending radius and the bending angle by changing the turning radius and the turning angle of the swing arm. Because it is a universal type that can be adjusted to a wide range, the equipment is remarkably cheaper than a mold-type device that needs to stock many bending dies. Despite being a universal type that does not use a mold, the material to be bent is clamped with a slip-free chuck, and a controlled axial stress is intentionally applied to the material being bent.
The ability, it is possible to secure a high processing accuracy comparable to mold located device. Therefore, it has been applied to the bending of high-precision multi-product pipes, such as steam generator tubes for pressurized water reactors, which used to be able to bend only with a die-forming device and required several dozen types of bending dies. Thus, a great cost reduction effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a bending device of the present invention.

FIG. 2 is a view taken along the line AA of FIG. 1;

FIG. 3 is a view taken in the direction of arrows BB in FIG. 1;

FIG. 4 is a view taken along line CC of FIG. 1;

FIG. 5 is a view taken along line DD in FIG. 1;

FIG. 6 is an enlarged view showing a groove type of a constraining roll.

FIG. 7 is a graph showing the results of investigating the effect of tensile force on ellipticality.

FIG. 8 is a stress distribution diagram for explaining the reason why tensile force and compressive force contribute to suppression of flattening.

FIG. 9 is an explanatory view of a bending process in a conventional dieless apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotating arm 2 Rotary table 4 Reduction gear 5 Motor 7 Slide base 8 Fixed base 13 Chuck 14 Inner constraining roll 15, 16 Outer constraining roll 17 Carriage 18 Linear way 19 Feed shaft 20 Motor

Claims (1)

(57) [Claims] 1. A tube rod is bent without using a bending die.
A bending device for bending a tube rod material , wherein the material to be bent is clamped by a chuck provided at a distal end side of a rotating shaft, and is forced at a predetermined speed around the rotating shaft.
Bending to be bent material by being rotated drive
At the same time , the rotating shaft is bent to change the bending radius.
Line perpendicular to the path line where the material to be bent is placed
Move up to change the distance from the rotation axis to the clamp.
A turning arm to be bent, which is positioned inside the material to be bent to be bent by the turning arm, supports the material to be bent, has a hole shape corresponding to the outer surface shape on the outer peripheral surface, and the rotation center is located on the line. Inside
And constraining rolls, positioned outside of the bending member is bent by the turning arm
To support the material to be bent in the pass line,
Outer Constraint with Hole on Outer Peripheral Surface Corresponding to External Shape
The roll and the rear end of the material to be bent disposed in the pass line are clamped, and the material to be bent is translated in the direction in which the material to be bent moves along the path line during bending, and the translation drive speed is rotated.
A carriage that applies controlled axial tension or compression to the material being bent by being controlled with respect to the rotational drive speed of the rotating arm. apparatus.