Title of Invention

A HIGH-SPEED BENDING METHOD OF A TUBE AND A THREE DIMENSIONAL BENDING DIE OF A TUBE

Abstract A high speed bending method of a tube in which the proximal end of the front side of a tube P under a three-dimensionally bent state is set, as a machining reference point, at the origin of an orthogonal coordinate defined by X, Y and Z axes, the positions one each axis on the coordinate, and angles to two vertical planes (3) and an angle to a horizontal plane of the coordinate at each position are determined for a plurality of points including a bend from the proximal end to the distal end of the rear side of that tube, the bending path of the tube P is formed in a block-like die member as a path groove (1) of three-dimensional bend based on positional data and angular data thus obtaining a three-dimensionally bending die G, proximal end of the straight tube P is set at the starting end of the path groove (1) in the bending die G, and a horizontal roller (4) is moved from the proximal end toward the distal end of the tube P while copying the path groove (1) and then the tube P is pushed into the path groove (1) and bent three-dimensionally.
Full Text

SPECIFICATION
HIGH SPEED BENDING METHOD OF RESIN TUBE AND THREE-DIMENSIONAL BENDING DIE EMPLOYED IN THE METHOD
TECHNICAL FIELD [0001]
The present invention mainly relates to a tube bending method and three-dimensionally bending a synthetic resin tube at high speed and a three-dimensional bending die employed in the method. BACKGROUND TECHNIQUE [0002]
A process of three-dimensionally bending the tube is a process widely used especially in a field of fuel tube, brake tube, or the like which requires high precision or in an industrial field which requires manufacturing of a wide variety of products in small quantities by the three-dimensional bending process. [0003]
In three-dimensional bending of a tube by a prior-art bending method, it is necessary to pressurize a portion to be bent from the same direction as a bending direction, i.e., it is necessary to cause a bending force to act on the bend in the same plane including the bend. For example, in roll bending shown in FIG. 6 as an example, a plurality of sets of three bending mechanisms Bl to B3 need be disposed according to bend attitudes

of respective bends given to each tube T or a bending device itself need be controlled three-dimensionally by an industrial robot. Therefore, three-dimensional bending equipment is adapted to a specialized use or a complicated and elaborate device is necessary, which necessitates a considerable equipment investment. [0004]
On the other hand, as shown in FIG. 7 as an example, there is a widespread three-dimensional bending by an NC bender in which a bending mechanism B is disposed at only one position, a straight portion of a tube T is gripped by a chuck Ch, and the chuck Ch feeds the tube T while twisting it to thereby carry out bending . However, this bending method employs the mechanism in which operation combining feed (advancement) and rotation (twisting) of the tube T by the chuck Ch is repeated. Therefore, the operation is carried out intermittently and the bending operation takes a long time. Moreover, if a bending track curves so that two bends approach each other and are not in the same plane, for example, the method cannot be used due to its limitation of the principle. [0005]
As described above, application of a force according to a bending direction to each bend in its bending plane is indispensable to the prior-art three-dimensional bending technique, which is a main cause of the problems of the prior art.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
[0006]
With the above prior-art problems in view, it is an object of the present invention to provide a method of three-dimensionally bending a tube only by moving a bending head for applying a force in vertical and horizontal directions along a bending track. Means to solve the Problems
[0007]
To achieve the above object, according to the present invention, there is provided a three-dimensional bending method, the method comprising the steps of: placing an end on a front side (hereafter referred to as a front end) of a tube in a three-dimensionally bent form on an origin point of rectangular coordinates formed of X, Y, and Z axes and using it as a bending fiducial point; obtaining positions on respective axes of the coordinates of each of a plurality of points including bends in a region from the front end to an opposite end (hereafter referred to as a rear end) of the tube and angles of each position with respect to two vertical planes and a horizontal plane on the coordinates; forming a bending track of the tube as a three-dimensional bending track groove in a block-shaped die member based on the obtained position data and angle data to thereby form a three-dimensional bending die; setting the front end of the straight tube to be bent in a starting end portion

of the track groove in the bending die; and moving a horizontal roller from the front end toward the rear end of the tube along the track groove to thereby push the tube into the track groove to three-dimensionally bend the tube.
[0008]
In the method of the invention, the resin tube in the three-dimensionally bent form is rotated about a central axis of the tube at the origin point on the rectangular coordinates formed of the X, Y, and Z axes and rotated in increments of GXY degrees, GXZ degrees, 0YZ degrees (0>l°) with respect to an XY plane, an XZ plane, and a YZ plane on the coordinates, respectively to thereby express the bending track of the tube by the position data and the angle data in a three-dimensional space (on the rectangular coordinates) through 360° about the central axis of the resin tube. In this way, an attitude of the three-dimensionally bent tube is defined. [0009]
Next, with regard to all the data of the bending track through 360° about the central axis of the resin tube, an angle (hereafter referred to as θ1) that a directional vector at each point on the bending track of the resin tube including the bends forms with the X axis in a direction of the XZ plane and an angle (hereafter referred to as θ 2) that the directional vector forms with a straight line passing through a starting point of the directional vector in a direction of the XY plane and parallel to the X axis, the angle θ 2 sandwiched on a side on which a rear

end of the directional vector is the closest to the straight
line are calculated.
[0010]
The whole bending track of the resin tube obtained by rotating these two angles θ1,θ2 through 360° about the central axis is obtained and the maximum value is calculated. The maximum value in each attitude through 360° about the central axis is defined as a reference value and an attitude of the tube in which the value becomes the minimum, i.e., a rotation angle about the central axis of the tube is calculated to determined the attitude
(orientation) of the tube on the coordinates.
[0011]
In other words, in the invention, position data of the plurality of points of the tube including the bends on the rectangular coordinates and the angle data of each position with respect to the vertical planes and the horizontal plane are formed by rotating the tube with a pitch of a proper angle through 360° about a central axis of the tube at the fiducial point and an attitude of the tube is formed as the track groove in the die member at a rotation angle at which the sum of the angle data of a position at the angle with respect to the vertical planes and the horizontal plane is the minimum to thereby form the three-dimensional bending die of the tube. By using the bending die and the horizontal roller for applying a force for pushing the tube into the track groove in the bending die, the three-dimensional high-speed bending of the tube can be achieved.

EFFECTS OF THE INVENTION
[0012]
In the present invention the end on the front side
(hereafter referred to as the front end) of the tube in the three-dimensionally bent form is placed on the origin point of the rectangular coordinates formed of X, Y, and Z axes to use it as the bending fiducial point. The positions on the respective axes of the coordinates of each of the plurality of points including the bends in the region from the front end to the opposite end (hereafter referred to as the rear end) of the tube and the angles of each position with respect to the two vertical planes and the horizontal plane on the coordinates are obtained. The bending track of the tube as the track groove is formed in the block-shaped die member based on the obtained position data and angle data to thereby form the three-dimensional bending die. Therefore, by setting the front end of the straight tube to be bent in the starting end portion of the track groove in the bending die and moving the horizontal roller from the front end toward the rear end of the tube along the track groove, it is possible to push the tube into the track groove at high speed to three-dimensionally bend the tube.
BEST MODE FOR CARRYING OUT THE INVENTION [0013]
An example for carrying out the above present invention

will be described with reference to FIGS. 1 to 3 . In the following description, a direction in which a groove extends is an X axis, a direction orthogonal to the groove is Y axis, a vertical direction is a Z axis, and a starting point of the groove is an origin point in a block B of rectangular coordinates for convenience of description.
In FIG. 3, first, a track in a f orm of a three-dimensionally bent tube to be obtained is carved as a groove 1 in a block B made of material such as metal, resin, and ceramic adequate for a purpose. Next, track faces 2 (hereafter referred to as upper faces 2 of a die) passing through a center line of the groove 1, kept perpendicular to both a vertical downward direction and the center line of the groove, at equal distances from the center line of the groove, and having proper widths are formed. Moreover, a portion of the block B except the upper faces 2 of the die is cut downward in the vertical direction to thereby form vertical faces 3 (hereafter referred to as vertical faces 3 of the die) at equal distances from the bending track of the tube in the horizontal direction. The whole part formed out of the material block B and including the groove 1, the die upper faces 2, and vertical faces 3 is referred to as a bending die G. Functions of the bending die G of the invention relies on the above shape and therefore the die G can be formed by cast molding or beam shaping besides the above-described cutting, i.e., a manufacturing method of the die G is not limited. [0014]

In FIG. 3, a circular cylindrical horizontal roller 4 is disposed above the upper faces 2 of the die G and vertical rollers
5 having central axes extending vertically downward on an
extension of a central axis of the horizontal roller 4 are disposed
on opposite sides of the horizontal roller 4. The vertical
rollers 5 pinch the vertical faces 3 to thereby fix an attitude
and the vertical rollers 5 and the horizontal roller 4 are retained
by a roller support member 6 to thereby form a bending head H
in which the horizontal roller 4 and the vertical rollers 5 are
mounted to the support member 6. The bending head H has a rotary
shaft 7 at its vertical upper portion and the shaft 7 is retained
by a bearing 8a of a holder 8. A cylinder 9 for receiving a
depressing force from above is provided to a holder 9a of the
bending head H. The bending head H is supported by the support
member 6 while kept horizontal. By moving the support member
6 in the horizontal direction with a cylinder 10 and in the vertical
direction with the cylinder 9, the head H is moved along the
upper faces 2 of the die G while pressing a tube P against an
inside of the groove 1 from an upper face of the tube P with
the horizontal roller 4.
[0015]
As a method of controlling the cylinders 9, 10 for moving the bending head H in the horizontal and vertical directions in the three-dimensional bending of the tube, mechanical control of a cam mechanism, electrical NC driving control, control by a cylinder and a sequencer, and the like can be utilized and

the controlling method is not limited in the invention. As the bearing 8a of the holder 8, it is also possible to use a rotation control device for rotating the shaft 7. In this case, it is possible to omit the vertical rollers 5. Moreover, if the horizontal roller 4 itself has a driving force, a driving mechanism and a control mechanism for it can be simplified in some cases. An example of the bending device for carrying out the method of the invention is formed in this way and is used in the following manner. [0016]
A front end of the straight tube P before bending is inserted into a starting end of the track groove 1 in the die G, the head H is brought down onto the front end, and the cylinder 9 applies certain depressing pressure while bringing the horizontal roller 4 and the upper faces 2 of the die G in close contact with each other. In this state, the cylinder 10 is actuated to move the whole head H along the track groove 1 from the starting end portion toward a terminal end side of the groove 1. As a result, the horizontal roller 4 rolling along the groove 1 successively generates a force for pushing the tube P into the track groove 1- At a portion where the track groove 1 is straight, this force acts in such a manner as to directly depress the tube P right below to successively insert the tube P into the track groove 1. At a portion where the track groove 1 is not straight, the force of the horizontal roller 4 generates forces for pressing the tube P against opposite wall faces of the track groove 1

and stress against the forces successively bends and inserts the tube P into the bent track groove 1. By moving the head H along the track groove 1 in this manner, it is possible to bend the tube P along the arbitrary three-dimensional track groove 1 formed in the die G. [0017]
According to the method of the invention, it is possible to three-dimensionally bend the tube P in the above manner. In the invention, if the tube P is heated prior to bending to reduce a Young's module and a finite strain of the tube P, the tree-dimensional bending can be carried out at higher speed, which results in a remarkable effect as compared with the three-dimensional bending by the prior-art known technique. [0018]
Moreover, in the invention, it is also possible to heat the tube P in the track groove 1 during or after bending of the tube P that has not been heated and at room temperature besides a so-called preheating bending method for three-dimensionally bending the resin tube P by the above method, the tube P being preheated and made easy to plastically deform. As a heating method, there are heating by an electric resistance heater, a heat-exchange tube, a microwave, and the like, high-frequency heating, far-infrared heating, and the like and the heat source and the heating method are not limited. [0019]
On the other hand, the invention can adapt to physical

properties of the tube P. In other words, it is possible to adapt to the tube P having the large Young' s module by increasing mechanical strength of the bending device. It is effective for bending to form an indention 4a corresponding to a diameter of the tube P in the horizontal roller 4 as shown in FIG. 3 as an example. Furthermore, it is also effective to provide guide rollers to the head H. In other words, in FIG. 3, the guide rollers 12, 12 in the same orientation as the vertical rollers 5, 5 are provided on opposite sides of a roller holder 11 provided to an extension portion 8b of the holder 8 through a vertical shaft 8c to guide and support movement of the head H along the track groove 1 on a front end side of the movement. [0020]
In case of material such as the resin tube P with a large strain in elastic limits, three-dimensional bending can be carried out at extremely high speed by changing the physical properties by preliminary treatment such as heating. Moreover, the bending method of the invention is also effective for a tube P such as a multi layer tube made of composite material and for a resin tube P having a rubber protector attached to it. Especially in case of a tube P a surface of which is made of material of large frictional resistance, it is effective to subject an inner surface of the groove 1 in the bending jig G to a friction reducing treatment such as hard plating, resin coating, silicon coating, and the like. [0021]

The above description is for the example in which the track
groove 1 formed in the die G has a planar shape constantly displaced
(moving) in positive directions with respect to a direction of
travel (a moving direction, a direction of the X axis) of the
horizontal roller 4 (or the bending head H).
However, depending on a three-dimensionally bent form of the tube P, even if the tube P is placed on an origin point of the coordinates and rotated through 360° about a central axis, the track groove 1 may reverse (i.e., a moving direction of the horizontal roller 4 may be a backward direction (return in an opposite direction) with respect to a direction shown by a straight line AB as shown in solid lines in FIGS. 4 and 5) in some cases.
Because a moving force in a positive direction on the X axis (straight line AB) is applied to the head H, high-speed bending cannot be implemented if the track groove 1 reverses on the die G (see a portion C in FIG. 4). This point causes the similar problem in case of a large bending angle. [0022]
Therefore, in the invention, in the cases in which the track groove 1 reverses or the bending angle is large (e.g., about 90° or an angle close to it), the die G itself in which the groove 1 is formed is turned in the plane. In other words, as shown in phantom lines in FIGS. 4 and 5, the die G is rotated clockwise at the starting point of the groove 1 of the die G or a point PI in a vicinity of the starting point in case of

FIG. 4 and the die G is rotated clockwise at a center of the die G or a point P2 in a vicinity of the center in case of FIG. 5 to thereby resolve the reverse. In the invention, it is essential only that the reverse and the large bending angle be resolved and therefore the rotating direction at the point P1 and P2 may be any of clockwise and counterclockwise directions. [0023]
(Example)
A straight nylon fuel tube having an outside shape of 8 mm, an internal diameter of 6 mm, and a length of 270 mm was bent under conditions in Table 1.
A device that was used was a tree-dimensional bending device for carrying out the method of the invention described based on FIGS. 1 to 3.
A tube to be bent was heated to about 150°C to 160°C as an example from a room temperature in advance. A front end of the tube was set in a groove 1 in the bending device and the bending head H was moved from a starting end portion toward a terminal end portion of the groove 1 in three seconds. After the movement of the head H, an inside of the tube was cooled for about 15 seconds to the room temperature.
A cycle time required for the bending of the tube was about 20 seconds excluding the preheating time. [0024]
[Table 1]


POSSIBILITIES OF INDUSTRIAL APPLICATION [0025]
The present invention is as described above. The end on the front side (hereafter referred to as the front end) of the tube in the three-dimensionally bent form is placed on the origin point of the rectangular coordinates formed of X, Y, and Z axes to use it as the bending fiducial point. The positions on the respective axes of the coordinates of each of the plurality of points including the bends in the region from the front end to the opposite end (hereafter referred to as the rear end) of the tube and the angles of each position with respect to the two vertical planes and the horizontal plane on the coordinates are obtained. The bending track of the tube as the track groove is formed in the block-shaped die member based on the obtained position data and angle data to thereby form the three-dimensional bending die. The front end of the straight tube to be bent is set in the starting end portion of the track groove in the bending die and the horizontal roller is moved from the front end toward the rear end of the tube along the

track groove to thereby push the tube into the track groove. Therefore, it is possible to three-dimensionally bend the synthetic resin tube or the metal tube easily and at low cost. [0026]
Because the method of the invention is as described above, it can be applied to a tube made of metal such as aluminum that regains its shape little after bending. Especially, it is extremely effective to apply the method to bending of a resin tube involving softening by heating.
BRIEF DESCRIPTION OF THE DRAWINGS [0027]
[FIG. 1]
A plan view of an example of a bending device for carrying out a method of the present invention.
[FIG. 2]
A front view of the bending device in FIG. 1.
[FIG. 3]
A perspective view showing an overview of a bending mechanism for explaining the method of the invention.
[FIG. 4]
A plan view of an example in which a bending die G used for the method of the invention is rotated in a horizontal plane.
[FIG. 5]
A plan view of another example in which a bending die G used for the method of the invention is rotated in a horizontal plane.

[FIG. 6]
A perspective view for explaining a prior-art roll bending device.
[FIG. 7] A perspective view for explaining a prior-art NC bender.
EXPLANATION OF REFERENCE NUMERALS [0028] G bending die
1 track groove
2 upper face
3 vertical face
4 horizontal roller
5 vertical roller
6 retaining member
7 rotary shaft

8, 9 holder 8a bearing
9, 10 cylinder H head
P tube


SPECIFICATION
HIGH SPEED BENDING METHOD OF RESIN TUBE AND THREE-DIMENSIONAL BENDING DIE EMPLOYED IN THE METHOD
TECHNICAL FIELD [0001]
The present invention mainly relates to a tube bending method and three-dimensionally bending a synthetic resin tube at high speed and a three-dimensional bending die employed in the method. BACKGROUND TECHNIQUE [0002]
A process of three-dimensionally bending the tube is a process widely used especially in a field of fuel tube, brake tube, or the like which requires high precision or in an industrial field which requires manufacturing of a wide variety of products in small quantities by the three-dimensional bending process. [0003]
In three-dimensional bending of a tube by a prior-art bending method, it is necessary to pressurize a portion to be bent from the same direction as a bending direction, i.e., it is necessary to cause a bending force to act on the bend in the same plane including the bend. For example, in roll bending shown in FIG. 6 as an example, a plurality of sets of three bending mechanisms Bl to B3 need be disposed according to bend attitudes

of respective bends given to each tube T or a bending device itself need be controlled three-dimensionally by an industrial robot. Therefore, three-dimensional bending equipment is adapted to a specialized use or a complicated and elaborate device is necessary, which necessitates a considerable equipment investment. [0004]
On the other hand, as shown in FIG. 7 as an example, there is a widespread three-dimensional bending by an NC bender in which a bending mechanism B is disposed at only one position, a straight portion of a tube T is gripped by a chuck Ch, and the chuck Ch feeds the tube T while twisting it to thereby carry out bending . However, this bending method employs the mechanism in which operation combining feed (advancement) and rotation (twisting) of the tube T by the chuck Ch is repeated. Therefore, the operation is carried out intermittently and the bending operation takes a long time. Moreover, if a bending track curves so that two bends approach each other and are not in the same plane, for example, the method cannot be used due to its limitation of the principle. [0005]
As described above, application of a force according to a bending direction to each bend in its bending plane is indispensable to the prior-art three-dimensional bending technique, which is a main cause of the problems of the prior art.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
[0006]
With the above prior-art problems in view, it is an object of the present invention to provide a method of three-dimensionally bending a tube only by moving a bending head for applying a force in vertical and horizontal directions along a bending track. Means to solve the Problems
[0007]
To achieve the above object, according to the present invention, there is provided a three-dimensional bending method, the method comprising the steps of: placing an end on a front side (hereafter referred to as a front end) of a tube in a three-dimensionally bent form on an origin point of rectangular coordinates formed of X, Y, and Z axes and using it as a bending fiducial point; obtaining positions on respective axes of the coordinates of each of a plurality of points including bends in a region from the front end to an opposite end (hereafter referred to as a rear end) of the tube and angles of each position with respect to two vertical planes and a horizontal plane on the coordinates; forming a bending track of the tube as a three-dimensional bending track groove in a block-shaped die member based on the obtained position data and angle data to thereby form a three-dimensional bending die; setting the front end of the straight tube to be bent in a starting end portion

of the track groove in the bending die; and moving a horizontal roller from the front end toward the rear end of the tube along the track groove to thereby push the tube into the track groove to three-dimensionally bend the tube.
[0008]
In the method of the invention, the resin tube in the three-dimensionally bent form is rotated about a central axis of the tube at the origin point on the rectangular coordinates formed of the X, Y, and Z axes and rotated in increments of GXY degrees, GXZ degrees, 0YZ degrees (0>l°) with respect to an XY plane, an XZ plane, and a YZ plane on the coordinates, respectively to thereby express the bending track of the tube by the position data and the angle data in a three-dimensional space (on the rectangular coordinates) through 360° about the central axis of the resin tube. In this way, an attitude of the three-dimensionally bent tube is defined. [0009]
Next, with regard to all the data of the bending track through 360° about the central axis of the resin tube, an angle (hereafter referred to as θ1) that a directional vector at each point on the bending track of the resin tube including the bends forms with the X axis in a direction of the XZ plane and an angle (hereafter referred to as θ 2) that the directional vector forms with a straight line passing through a starting point of the directional vector in a direction of the XY plane and parallel to the X axis, the angle θ 2 sandwiched on a side on which a rear

end of the directional vector is the closest to the straight
line are calculated.
[0010]
The whole bending track of the resin tube obtained by rotating these two angles θ1,θ2 through 360° about the central axis is obtained and the maximum value is calculated. The maximum value in each attitude through 360° about the central axis is defined as a reference value and an attitude of the tube in which the value becomes the minimum, i.e., a rotation angle about the central axis of the tube is calculated to determined the attitude
(orientation) of the tube on the coordinates.
[0011]
In other words, in the invention, position data of the plurality of points of the tube including the bends on the rectangular coordinates and the angle data of each position with respect to the vertical planes and the horizontal plane are formed by rotating the tube with a pitch of a proper angle through 360° about a central axis of the tube at the fiducial point and an attitude of the tube is formed as the track groove in the die member at a rotation angle at which the sum of the angle data of a position at the angle with respect to the vertical planes and the horizontal plane is the minimum to thereby form the three-dimensional bending die of the tube. By using the bending die and the horizontal roller for applying a force for pushing the tube into the track groove in the bending die, the three-dimensional high-speed bending of the tube can be achieved.

EFFECTS OF THE INVENTION
[0012]
In the present invention the end on the front side
(hereafter referred to as the front end) of the tube in the three-dimensionally bent form is placed on the origin point of the rectangular coordinates formed of X, Y, and Z axes to use it as the bending fiducial point. The positions on the respective axes of the coordinates of each of the plurality of points including the bends in the region from the front end to the opposite end (hereafter referred to as the rear end) of the tube and the angles of each position with respect to the two vertical planes and the horizontal plane on the coordinates are obtained. The bending track of the tube as the track groove is formed in the block-shaped die member based on the obtained position data and angle data to thereby form the three-dimensional bending die. Therefore, by setting the front end of the straight tube to be bent in the starting end portion of the track groove in the bending die and moving the horizontal roller from the front end toward the rear end of the tube along the track groove, it is possible to push the tube into the track groove at high speed to three-dimensionally bend the tube.
BEST MODE FOR CARRYING OUT THE INVENTION [0013]
An example for carrying out the above present invention

will be described with reference to FIGS. 1 to 3 . In the following description, a direction in which a groove extends is an X axis, a direction orthogonal to the groove is Y axis, a vertical direction is a Z axis, and a starting point of the groove is an origin point in a block B of rectangular coordinates for convenience of description.
In FIG. 3, first, a track in a f orm of a three-dimensionally bent tube to be obtained is carved as a groove 1 in a block B made of material such as metal, resin, and ceramic adequate for a purpose. Next, track faces 2 (hereafter referred to as upper faces 2 of a die) passing through a center line of the groove 1, kept perpendicular to both a vertical downward direction and the center line of the groove, at equal distances from the center line of the groove, and having proper widths are formed. Moreover, a portion of the block B except the upper faces 2 of the die is cut downward in the vertical direction to thereby form vertical faces 3 (hereafter referred to as vertical faces 3 of the die) at equal distances from the bending track of the tube in the horizontal direction. The whole part formed out of the material block B and including the groove 1, the die upper faces 2, and vertical faces 3 is referred to as a bending die G. Functions of the bending die G of the invention relies on the above shape and therefore the die G can be formed by cast molding or beam shaping besides the above-described cutting, i.e., a manufacturing method of the die G is not limited. [0014]

In FIG. 3, a circular cylindrical horizontal roller 4 is disposed above the upper faces 2 of the die G and vertical rollers
5 having central axes extending vertically downward on an
extension of a central axis of the horizontal roller 4 are disposed
on opposite sides of the horizontal roller 4. The vertical
rollers 5 pinch the vertical faces 3 to thereby fix an attitude
and the vertical rollers 5 and the horizontal roller 4 are retained
by a roller support member 6 to thereby form a bending head H
in which the horizontal roller 4 and the vertical rollers 5 are
mounted to the support member 6. The bending head H has a rotary
shaft 7 at its vertical upper portion and the shaft 7 is retained
by a bearing 8a of a holder 8. A cylinder 9 for receiving a
depressing force from above is provided to a holder 9a of the
bending head H. The bending head H is supported by the support
member 6 while kept horizontal. By moving the support member
6 in the horizontal direction with a cylinder 10 and in the vertical
direction with the cylinder 9, the head H is moved along the
upper faces 2 of the die G while pressing a tube P against an
inside of the groove 1 from an upper face of the tube P with
the horizontal roller 4.
[0015]
As a method of controlling the cylinders 9, 10 for moving the bending head H in the horizontal and vertical directions in the three-dimensional bending of the tube, mechanical control of a cam mechanism, electrical NC driving control, control by a cylinder and a sequencer, and the like can be utilized and

the controlling method is not limited in the invention. As the bearing 8a of the holder 8, it is also possible to use a rotation control device for rotating the shaft 7. In this case, it is possible to omit the vertical rollers 5. Moreover, if the horizontal roller 4 itself has a driving force, a driving mechanism and a control mechanism for it can be simplified in some cases. An example of the bending device for carrying out the method of the invention is formed in this way and is used in the following manner. [0016]
A front end of the straight tube P before bending is inserted into a starting end of the track groove 1 in the die G, the head H is brought down onto the front end, and the cylinder 9 applies certain depressing pressure while bringing the horizontal roller 4 and the upper faces 2 of the die G in close contact with each other. In this state, the cylinder 10 is actuated to move the whole head H along the track groove 1 from the starting end portion toward a terminal end side of the groove 1. As a result, the horizontal roller 4 rolling along the groove 1 successively generates a force for pushing the tube P into the track groove 1- At a portion where the track groove 1 is straight, this force acts in such a manner as to directly depress the tube P right below to successively insert the tube P into the track groove 1. At a portion where the track groove 1 is not straight, the force of the horizontal roller 4 generates forces for pressing the tube P against opposite wall faces of the track groove 1

and stress against the forces successively bends and inserts the tube P into the bent track groove 1. By moving the head H along the track groove 1 in this manner, it is possible to bend the tube P along the arbitrary three-dimensional track groove 1 formed in the die G. [0017]
According to the method of the invention, it is possible to three-dimensionally bend the tube P in the above manner. In the invention, if the tube P is heated prior to bending to reduce a Young's module and a finite strain of the tube P, the tree-dimensional bending can be carried out at higher speed, which results in a remarkable effect as compared with the three-dimensional bending by the prior-art known technique. [0018]
Moreover, in the invention, it is also possible to heat the tube P in the track groove 1 during or after bending of the tube P that has not been heated and at room temperature besides a so-called preheating bending method for three-dimensionally bending the resin tube P by the above method, the tube P being preheated and made easy to plastically deform. As a heating method, there are heating by an electric resistance heater, a heat-exchange tube, a microwave, and the like, high-frequency heating, far-infrared heating, and the like and the heat source and the heating method are not limited. [0019]
On the other hand, the invention can adapt to physical

properties of the tube P. In other words, it is possible to adapt to the tube P having the large Young' s module by increasing mechanical strength of the bending device. It is effective for bending to form an indention 4a corresponding to a diameter of the tube P in the horizontal roller 4 as shown in FIG. 3 as an example. Furthermore, it is also effective to provide guide rollers to the head H. In other words, in FIG. 3, the guide rollers 12, 12 in the same orientation as the vertical rollers 5, 5 are provided on opposite sides of a roller holder 11 provided to an extension portion 8b of the holder 8 through a vertical shaft 8c to guide and support movement of the head H along the track groove 1 on a front end side of the movement. [0020]
In case of material such as the resin tube P with a large strain in elastic limits, three-dimensional bending can be carried out at extremely high speed by changing the physical properties by preliminary treatment such as heating. Moreover, the bending method of the invention is also effective for a tube P such as a multi layer tube made of composite material and for a resin tube P having a rubber protector attached to it. Especially in case of a tube P a surface of which is made of material of large frictional resistance, it is effective to subject an inner surface of the groove 1 in the bending jig G to a friction reducing treatment such as hard plating, resin coating, silicon coating, and the like. [0021]

The above description is for the example in which the track
groove 1 formed in the die G has a planar shape constantly displaced
(moving) in positive directions with respect to a direction of
travel (a moving direction, a direction of the X axis) of the
horizontal roller 4 (or the bending head H).
However, depending on a three-dimensionally bent form of the tube P, even if the tube P is placed on an origin point of the coordinates and rotated through 360° about a central axis, the track groove 1 may reverse (i.e., a moving direction of the horizontal roller 4 may be a backward direction (return in an opposite direction) with respect to a direction shown by a straight line AB as shown in solid lines in FIGS. 4 and 5) in some cases.
Because a moving force in a positive direction on the X axis (straight line AB) is applied to the head H, high-speed bending cannot be implemented if the track groove 1 reverses on the die G (see a portion C in FIG. 4). This point causes the similar problem in case of a large bending angle. [0022]
Therefore, in the invention, in the cases in which the track groove 1 reverses or the bending angle is large (e.g., about 90° or an angle close to it), the die G itself in which the groove 1 is formed is turned in the plane. In other words, as shown in phantom lines in FIGS. 4 and 5, the die G is rotated clockwise at the starting point of the groove 1 of the die G or a point PI in a vicinity of the starting point in case of

FIG. 4 and the die G is rotated clockwise at a center of the die G or a point P2 in a vicinity of the center in case of FIG. 5 to thereby resolve the reverse. In the invention, it is essential only that the reverse and the large bending angle be resolved and therefore the rotating direction at the point P1 and P2 may be any of clockwise and counterclockwise directions. [0023]
(Example)
A straight nylon fuel tube having an outside shape of 8 mm, an internal diameter of 6 mm, and a length of 270 mm was bent under conditions in Table 1.
A device that was used was a tree-dimensional bending device for carrying out the method of the invention described based on FIGS. 1 to 3.
A tube to be bent was heated to about 150°C to 160°C as an example from a room temperature in advance. A front end of the tube was set in a groove 1 in the bending device and the bending head H was moved from a starting end portion toward a terminal end portion of the groove 1 in three seconds. After the movement of the head H, an inside of the tube was cooled for about 15 seconds to the room temperature.
A cycle time required for the bending of the tube was about 20 seconds excluding the preheating time. [0024]
[Table 1]


POSSIBILITIES OF INDUSTRIAL APPLICATION [0025]
The present invention is as described above. The end on the front side (hereafter referred to as the front end) of the tube in the three-dimensionally bent form is placed on the origin point of the rectangular coordinates formed of X, Y, and Z axes to use it as the bending fiducial point. The positions on the respective axes of the coordinates of each of the plurality of points including the bends in the region from the front end to the opposite end (hereafter referred to as the rear end) of the tube and the angles of each position with respect to the two vertical planes and the horizontal plane on the coordinates are obtained. The bending track of the tube as the track groove is formed in the block-shaped die member based on the obtained position data and angle data to thereby form the three-dimensional bending die. The front end of the straight tube to be bent is set in the starting end portion of the track groove in the bending die and the horizontal roller is moved from the front end toward the rear end of the tube along the

track groove to thereby push the tube into the track groove. Therefore, it is possible to three-dimensionally bend the synthetic resin tube or the metal tube easily and at low cost. [0026]
Because the method of the invention is as described above, it can be applied to a tube made of metal such as aluminum that regains its shape little after bending. Especially, it is extremely effective to apply the method to bending of a resin tube involving softening by heating.
BRIEF DESCRIPTION OF THE DRAWINGS [0027]
[FIG. 1]
A plan view of an example of a bending device for carrying out a method of the present invention.
[FIG. 2]
A front view of the bending device in FIG. 1.
[FIG. 3]
A perspective view showing an overview of a bending mechanism for explaining the method of the invention.
[FIG. 4]
A plan view of an example in which a bending die G used for the method of the invention is rotated in a horizontal plane.
[FIG. 5]
A plan view of another example in which a bending die G used for the method of the invention is rotated in a horizontal plane.

[FIG. 6]
A perspective view for explaining a prior-art roll bending device.
[FIG. 7] A perspective view for explaining a prior-art NC bender.
EXPLANATION OF REFERENCE NUMERALS [0028] G bending die
1 track groove
2 upper face
3 vertical face
4 horizontal roller
5 vertical roller
6 retaining member
7 rotary shaft

8, 9 holder 8a bearing
9, 10 cylinder H head
P tube



WHAT IS CLAIMED IS:
1. A high-speed bending method of a tube, the method comprising the steps of: placing an end on a front side (hereafter referred to as a front end) of a tube in a three-dimensionally bent form on an origin point of rectangular coordinates formed of X, Y, and Z axes and using it as a bending fiducial point; obtaining positions on respective axes of the coordinates of each of a plurality of points including bends in a region from the front end to an opposite end (hereafter referred to as a rear end) of the tube and angles of each position with respect to two vertical planes and a horizontal plane on the coordinates; forming a bending track of the tube as a three-dimensional bending track groove in a block-shaped die member based on the obtained position data and angle data to thereby form a three-dimensional bending die; setting the front end of the straight tube to be bent in a starting end portion of the track groove in the bending die; and moving a horizontal roller from the front end toward the rear end of the tube along the track groove to thereby push the tube into the track groove to three-dimensionally bend the tube.
2. The high-speed bending method of a tube according to claim 1, wherein position data of the plurality of points of the tube including the bends on the rectangular coordinates and the angle data of each position with respect to the vertical planes and the horizontal plane are formed at each rotation angle

through which the tube is rotated with a pitch of a proper angle about a central axis of the tube at the fiducial point and an attitude of the tube is formed as the track groove in the die member at a rotation angle at which the sum of the angle data of a position at the angle with respect to the vertical planes and the horizontal plane is the minimum.
3. The high-speed bending method of a tube according to claim 1 or 2, wherein, if the track groove reverses or has a large bending angle in a moving direction of the horizontal roller, the reverse is resolved or the large bending angle is made small in appearance by angular rotation of the three-dimensional bending die provided with the track groove.
4. The high-speed bending method of a tube according to any one of claims 1 to 3, wherein the horizontal roller formed with an indention corresponding to a diameter of the tube is used.
5. The high-speed bending method of a tube according to any one of claims 1 to 4, wherein vertical rollers are provided on opposite sides of the moving direction of the horizontal roller and the bending is carried out with the vertical rollers along outer wall faces of the track groove.
6. The high-speed bending method of a tube according to any one of claims 1 to 5, wherein a surface of the track groove is subjected to a friction reducing treatment.
7. The high-speed bending method of a tube according to any one of claims 1 to 6, wherein the tube is a resin tube, a

resin tube attached with a rubber protector, or a metal tube. 8. A three-dimensional bending die of a tube, wherein position data of a plurality of points of a tube including bends on rectangular coordinates and angle data of each position with respect to vertical planes and horizontal plane are formed at each rotation angle through which the tube is rotated with a pitch of a proper angle about a central axis of the tube at a fiducial point and an attitude of the tube is formed as a track groove in a die member at a rotation angle at which the sum of angle data of a position at the angle with respect to the vertical planes and the horizontal plane is the smallest.








Documents:

1598-CHENP-2007 AMENDED CLAIMS 04-11-2013.pdf

1598-CHENP-2007 AMENDED PAGES OF SPECIFICATION 04-11-2013.pdf

1598-CHENP-2007 CORRESPONDENCE OTHERS 08-04-2013.pdf

1598-CHENP-2007 EXAMINATION REPORT REPLY RECEIVED 04-11-2013.pdf

1598-CHENP-2007 FORM-1 04-11-2013.pdf

1598-CHENP-2007 FORM-3 04-11-2013.pdf

1598-CHENP-2007 OTHER PATENT DOCUMENT 04-11-2013.pdf

1598-CHENP-2007 OTHER PATENT DOCUMENT 1 04-11-2013.pdf

1598-CHENP-2007 POWER OF ATTORNEY 04-11-2013.pdf

1598-chenp-2007-abstract.pdf

1598-chenp-2007-claims.pdf

1598-chenp-2007-correspondnece-others.pdf

1598-chenp-2007-description(complete).pdf

1598-chenp-2007-drawings.pdf

1598-chenp-2007-form 1.pdf

1598-chenp-2007-form 3.pdf

1598-chenp-2007-form 5.pdf

1598-chenp-2007-pct.pdf


Patent Number 258026
Indian Patent Application Number 1598/CHENP/2007
PG Journal Number 48/2013
Publication Date 29-Nov-2013
Grant Date 27-Nov-2013
Date of Filing 19-Apr-2007
Name of Patentee HAYAKAWA SEISAKUSHO CO., LTD
Applicant Address 6-24, EDO 1-CHOME , KAWAGUCHI-SHI , SAITAMA 334-0074, JAPAN
Inventors:
# Inventor's Name Inventor's Address
1 KOBAYASHI, TAKESHI C/O HAYAKAWA SEISAKUSHO CO.,LTD., KOUMI FACTORY, 2117-1, OHAZATOYOSATO , KOUMIMACHI, MINAMISAKU-GUN, NAGANO 384-1103, JAPAN
PCT International Classification Number B29C 53/08
PCT International Application Number PCT/JP04/15492
PCT International Filing date 2004-10-20
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA