JPH09103825A - Die turning mechanism in pushing through bending device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably execute bending with a smaller bending radius in high precision in a pushing through bending device of a tube stock, etc. SOLUTION: The bending device is provided with a guide cylinder 3 to make a tube stock 60 inserted therein, a die 1 having spherically shaped peripheral side face and to clamp part of the tube stock 60 piercing through the guide cylinder 3 with a bearing part 1b and a die holder 2 to hold the die 1 turnably, in the pushing through bending device to push through the tube stock 60 while imparting offset U to the die 1, the bearing part 1b of the die 1 is positioned more to the delivery side of the tube stock 60 than the turning center C1 of the die 1, a spherical curved part 3a formed at the surrounding of delivery outlet of the guide cylinder 3 is internally fitted/abutted to an annular projecting part la of cylindrical inner face arranged to the die 1. When imparting the offset U, the internally fitted abutted state is constantly maintained, unstable turning of the die 1 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die rotating mechanism in a press-through bending apparatus for a pipe material or the like, and in a special bending process, a die inclination angle required to configure more ideal bending conditions. And a mechanism for automatically and stably setting the.

[0002]

2. Description of the Related Art As a means for bending pipes, profiles, or solid materials (hereinafter referred to as "tubes, etc.") with high accuracy using a simple apparatus, the present applicant has adopted a "press-through bending method and the same method". Bending device '' (Japanese Patent Publication No. 5-12047, Patent No. 1804036)
Has been proposed.

[0003] This processing method is composed of a guide cylinder that allows a tube or the like to be inserted while being held, and a die that holds a part of the tube or the like penetrating the guide cylinder by a bearing portion. A bending method characterized in that a pipe or the like is pushed through a guide cylinder and a die while the center of the bearing portion of the die is relatively offset. According to the method, the offset U between the guide cylinder and the die is determined. Only by controlling, it is possible to perform continuous bending processing having a bending radius Rp corresponding to the offset U, and to realize processing in which cross-sectional deformation of a pipe or the like is suppressed. That is, by setting the offset U, for a tube or the like that is continuously pushed by the action of a bending moment M corresponding to the product of the force of the bearing unit pressing the tube or the like and the approach (the interval between the bearing unit and the guide cylinder) V by the setting of the offset U The bearing section restrains the periphery of the tube material or the like, thereby correcting the flattening of the tube material or the like and preventing the cross section from being deformed.

[0004] However, the above-mentioned method and its apparatus also have limitations on the bending conditions. That is, when the offset U is set to be large, the bending moment M becomes large, and the bending radius Rp of the pipe material or the like can be made small. However, when the offset U becomes a certain value or more, the inclination angle of the die is correspondingly increased. Otherwise, the sliding contact force between the pipe and the like and the bearing portion is abnormally increased, and normal bending cannot be performed. In addition, if the inclination angle of the die is not provided, there is a problem that flattening occurs in the pipe material and the like, and processing accuracy is reduced.

[0005] In order to solve the problem, the present applicant has proposed a die mechanism capable of setting the inclination angle of the die to the optimum angle with respect to the basic invention described above (Japanese Patent Laid-Open No. 4-197528). ). FIG. 4 shows a specific configuration of a push-through bending apparatus based on the proposal. In the figure, 51 is a die, 52 is a die holder, 53 is a guide cylinder, the guide cylinder 53 is inserted while holding the tube 60, and the tube 60 penetrating the guide cylinder 53 is a bearing 51b of the die 51. Have been detained by The die holder 52 is fixed to the drive base 70, and the die 51 can be offset relative to the guide cylinder 53 by forcibly moving the drive base 70 in a vertical plane. ing.

FIG. 5 shows the details and interrelationships of the mechanical elements in the above-mentioned apparatus. First, the die 51 is formed such that the peripheral side surface is formed into a spherical curved surface (radius of curvature Rd) having the center C1 on the insertion port side of the tube member 60 with respect to the center C2 of the bearing portion 51b, And an annular protruding portion 51a having a tapered inner surface formed at the bottom. On the other hand, the die holder 52 has a curved surface that holds the spherical curved surface of the die 51, and holds the die 51 so as to face the guide cylinder 53. Further, an annular protrusion 51a of a die 51 is provided around the guide cylinder 53 on the side of the outlet of the tube material 60.
Is formed with a control curved surface 53a.

The control curved surface 53a formed on the guide cylinder 53 is a die holder 5 as shown in FIG.
2 moves relative to the guide cylinder 51 to give an offset, and the die 51 is
The surface including the bearing portion 51b of the die 51 is formed as a curved surface that is set to be substantially vertical when viewed from the center of the outlet of the guide cylinder 51 when the annular protrusion 51a of the die 51 abuts and rotates. Have been.

Therefore, when the pipe 60 is pushed through in the offset state shown in FIG. 6, the die 51 rotates and tilts due to the application of the offset U. However, the center C1 relating to the spherical curved surface on the peripheral side surface of the die 51 becomes the center C2 of the bearing portion 51b. And the offset distance side (the lower side in the figure) of the bearing portion 51b becomes a strong sliding contact area with the pipe material 60, so that the die
51 will be rotated in the direction of further inclination. In other words, a rotational moment M is generated in the die 51 itself due to the displacement (Δy) of the center C2 of the bearing part 51b due to the sliding joining force between the die 51 and the tube member 60 and the rotation of the die 51, and the rotational moment M causes the inclination of the die 51 Increase further.

In this case, the ideal condition for performing bending with a lighter sliding contact force without causing flattening of the pipe material 60 is that the surface S including the bearing portion 51b of the die 51 has the same bearing. That is, it is perpendicular to the central axis of the pipe material 60 passing through the portion 51b. Therefore, in the die mechanism according to this proposal, the inclination angle of the die 51 due to the rotational moment M is controlled by the contact relationship between the annular projection 51a of the die 51 and the control curved surface 53a of the guide cylinder 53, and the ideal I am trying to get the conditions. Specifically, when the offset U is given to the die 51, a rotational moment M is inevitably generated, and the annular protrusion 51 of the die 51 is formed.
The inner peripheral surface of a is in contact with the surface of the control curved surface 53a of the guide cylinder 53. However, since the control curved surface 53a of the guide cylinder 53 is formed as a curved surface as described above, the die 51 is Can be constrained to an ideal angle.

[0010]

By applying the "die mechanism" of JP-A-4-197528 to the "press-through bending method and apparatus" of the basic invention, seemingly ideal bending can be achieved. Although it seems to be feasible, the following problems arise with respect to the actual bending process and the manufacture of mechanical elements. (1) Since the center C2 of the bearing portion 51b is located rearward of the center C1 of the spherical curved surface of the peripheral side surface of the die 51, when the offset U is increased and the bending radius of the pipe material 60 is reduced, The pipe material 60 sent out after processing comes into contact with the die holder 52. That is, a large distance between the bearing portion 51b and the front surface of the die holder 52 is a factor that hinders a reduction in bending radius. (2) The displacement (Δy) of the center C2 of the bearing portion 51b due to the rotation of the die 51 is a distance factor that generates the bending moment M. Since the displacement (Δy) is a minute distance, the bending moment M is not so large. Not a large value. Also, as is apparent from FIG.
The annular protruding portion 51a is in contact with the control curved surface 53a of the guide cylinder 53 on one side (upper side), but is separated on the other side (lower side). Is in a free state. Therefore, a force other than the acting force related to the rotational moment M (for example, the tube material 60) is applied to the die 51.
If a force or the like induced when “wrinkles” occur in the tube material 60 acts, the die 51 enters an unstable rotation state and the machining accuracy decreases. Further, such an unstable state is likely to occur when the offset U is increased and the bending radius is reduced, so that it becomes a serious obstacle in reducing the bending radius. (3) The control curved surface 53a of the guide cylinder 53 has to form a complicated curved surface in a relatively small area with high precision, and the machining is very troublesome.

Therefore, the present invention has been made in view of the above problems,
It was created with the aim of providing a die turning mechanism capable of realizing stable and accurate push-through bending even when the bending radius is reduced by increasing the offset U.

[0012]

SUMMARY OF THE INVENTION According to the present invention, there is provided a guide cylinder which allows a tubular member, a shaped member or a solid member to be inserted while being held, and a part of the tubular member penetrating the guide cylinder is held by a bearing portion. An apparatus for performing bending by pushing a pipe or the like through the guide cylinder and the die in a state where the center axis of the guide cylinder and the center of the bearing portion of the die are relatively offset from each other. Is formed as a spherical curved surface having a center on the insertion port side of the pipe material etc. from the center of the bearing part, and passes through the center of the bearing part and is perpendicular to the surface containing the bearing part on the insertion port side of the pipe material etc. And a curved surface that embraces a spherical curved surface of the die, and a die in which an annular protrusion having a cylindrical inner peripheral surface having a straight line as a central axis is integrally formed. A die holder for holding the die in opposition to the guide cylinder, and a periphery of the outlet of the pipe, etc., having a center on the central axis of the through hole of the pipe, etc., and having a maximum diameter portion with respect to the annular protrusion of the die. And a guide cylinder provided with a spherically curved surface portion that abuts and fits inside.

In the present invention, since the center of the spherical curved surface on the peripheral side surface of the die is closer to the insertion opening of the tube material or the like than the center of the bearing portion, the die and the tube material or the like are subjected to the offset bending work. Considering the sliding contact condition and the deviation position of the center of the bearing portion, almost no rotational moment is generated in the die. On the other hand, the annular protrusion of the die
Irrespective of the offset, it always fits inside the spherical curved surface of the guide cylinder over the entire circumference. Therefore, even if a rotational moment in any direction is generated in the die due to various acting forces generated in a continuous bending state of a pipe material or the like, the die is completely constrained to a tilt angle corresponding to the offset. , Stable and accurate bending can be realized. Further, since the center of the bearing portion of the die is located closer to the delivery side of the tube material and the like than the center of the spherical curved surface of the peripheral side surface of the die, the bent portion is located on the front side of the die holder (tube material etc.) as shown in FIG. Outgoing side). As a result, it is possible to configure an advantageous condition for avoiding that the pipe material or the like after the bending process comes into contact with the die holder,
Factors that hindered the reduction of the bending radius can be reduced.

By the way, in the configuration of the present invention, there is no guarantee that the surface including the bearing portion of the die is perpendicular to the axis of the pipe or the like passing through the portion in the state where the offset is given. In that case, if the distance between the die holder and the guide cylinder is made adjustable by providing a moving means for moving the die holder or / and the guide cylinder in the insertion direction of the pipe material or the like, and if the distance is adjusted corresponding to the offset, Can be obtained.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the "die rotating mechanism in a push-through bending apparatus" of the present invention will be described below in detail with reference to FIGS. First, FIG. 1 is a cross-sectional view showing the configuration of the die rotating mechanism in the state where the offset is 0, 1 is a die, 2 is a die holder, and 3 is a guide cylinder. As in the case of FIG. While the guide cylinder 3 is inserted while holding the tube material 60,
The pipe material 60 penetrating the guide cylinder 3 is held by the bearing 1b of the die 1.

The die 1 has a spherical curved surface (radius of curvature Rd) formed on the peripheral side surface thereof, and the die holder 2 has a curved surface for holding the spherical curved surface of the die 5. And an annular protruding portion 1a is formed on the die 1 at the insertion port side of the tube member 60, and the annular protruding portion 1a internally fits the distal end portion of the guide cylinder 3. This is the same as the conventional dice mechanism shown in FIGS. 4 to 6, but the dice turning mechanism of the present embodiment has the following features. The center C1 of the spherical curved surface of the peripheral side surface of the die 1 is located closer to the insertion port side of the pipe member 60 than the center C2 of the bearing portion 1b. In the conventional die mechanism (FIG. 5), the annular projection 5 of the die 51 is used.
Although the inner peripheral surface of 1a is formed in a tapered shape, the annular projection 1a of the die 1 of the present embodiment has a bearing 1b.
And a cylindrical inner peripheral surface 1c having a central axis defined by a straight line perpendicular to the surface S including the bearing portion 1b. A spherical curved surface portion 3a is formed around the outlet of the tube material 60 in the guide cylinder 3, and the curved surface portion 3a is
The through-hole is a spherical surface having a center on the central axis of the through hole, and the largest diameter portion of the spherical surface is in-fitted in contact with the cylindrical inner peripheral surface 1c of the annular projecting portion 1a of the die 1.

In the die rotating mechanism having the above characteristics, when the die 1 is moved vertically to give an offset U as shown in FIG. 2, the spherical curved surface portion 3a of the guide cylinder 3 and the annular shape of the die 1 are formed. The die 1 is forcibly rotated in the die holder 2 and inclined by the engagement relationship of the protrusions 1a. When the tube 60 is pushed through in the offset state, a stronger sliding contact condition is formed below the bearing portion 1b of the die 1 and the center C2 of the bearing portion 1b is slightly smaller than the center C1 of the spherical curved surface of the die 1. In this case, the deviation (Δy ′) is shifted with respect to the rotation center C1 in FIG.
Therefore, the rotational moment acting on the die 1 is extremely small. In any case, die 1
Is a tube member whose inclination angle is uniquely set based on the above-described engagement relationship, and in which state, the pipe member is pushed through in the same manner as in FIG.
A bending moment always acts on 60, and the tube material 60 is sent out from the bearing portion 1b of the die 1 while being continuously bent.

According to this die mechanism, the spherical curved surface portion 3a having a center on the center axis of the through hole of the pipe member 60 of the guide cylinder 3 is formed on the cylindrical inner peripheral surface 1c of the annular projecting portion 1a of the die 1. Irrespective of the size of the offset U, the spherical curved surface portion 3a and the cylindrical inner peripheral surface 1c are always in contact with each other over the entire circumference. That is, no matter what rotational moment acts on the die 1 during the bending process of the tube material 60, the die 1 is compulsorily set to the inclined state determined by the offset U. As a result, the dice
Since the bending process of the tube material 60 by the bearing portion 1b is continuously performed in a stable state and the inclination angle of the die 1 changes smoothly even when the offset U is changed over time, extremely high precision is achieved. Continuous bending can be realized.

When the continuous bending is performed, the tube material 60 is sent out from the bearing portion 1b of the die 1 and is curved toward the die holder 2 side.
If the bend radius is set to a small value by setting a large value, the gap between the part of the pipe material 60 that returns to the die holder 2 side after bending and the die holder 2 becomes a problem, and the bend radius is set only in the range where the return part does not contact the die holder 2. It cannot be made smaller. However, in this embodiment, the center C2 of the bearing portion 1b of the die 1 is the center C1 of the spherical curved surface.
Since it is located closer to the sending side, it is possible to allow a margin for obtaining the above-mentioned interval. That is, the conventional die mechanism
It becomes possible to bend the tube 60 with a smaller bending radius than in the case of FIG. 6.

Next, as described in the conventional die mechanism, in order to perform an ideal bending process in which the pushing force is small and the flattening of the pipe member 60 is not caused, the surface S including the bearing portion 1b of the die 1 is required. Must be perpendicular to the axial direction of the tube material 60 passing through the bearing portion 1b. Then, only the configuration of the present embodiment can stabilize the bending process and increase the precision, but cannot guarantee the ideal condition of the bending mechanism. That is, when the offset U is small, the inclination angle of the die 1 is small, so that there is not much problem. However, when the offset U is large, the pushing force increases and the flattening rate increases.

However, it is easy to satisfy the ideal condition of the bending process in the configuration of the present embodiment. This is because it is possible to secure the above ideal condition by adjusting the approach V corresponding to the bearing portion 1b of the die 1 and the end portion of the guide cylinder 3. Specifically, a drive mechanism is provided not only for moving the drive base 70 fixing the die holder 2 in a vertical plane, but also for moving and adjusting the drive base 70 in the front-rear direction corresponding to the offset U set by the movement. The bearing part 1b of the die 1
It is sufficient to obtain a vertical relationship in the axial direction between the surface S including the above and the tube material 60 passing through the bearing portion 1b. However, the tube material, offset U, approach V, and bending radius R of the tube material are determined in advance.
The relationship of p is determined empirically, and the approach V corresponding to the offset U is selected and adjusted so that optimum bending conditions are obtained when a certain bending radius Rp is obtained. Such control is performed by storing data relating to the above-described optimum bending conditions in a memory or the like in advance, and a microcomputer that moves the drive base 70 vertically and horizontally and back and forth based on the stored data. It can be easily realized by configuring a system that controls a motor or the like.

Although the present embodiment has been described with respect to the bending of the pipe member 60, it is needless to say that the above-described die rotating mechanism can be applied to the press-through bending of a shape member or a solid member. In the case of a section having no circular cross section, such as a profile, the bearing portion of the die may be formed in a shape corresponding thereto. Further, in the present embodiment, the offset U and the approach V are given by moving the die 1 side, but the same condition can be relatively configured by moving the guide cylinder 3 side.

[0023]

FIG. 3 is a graph showing the change in the bending radius Rp with respect to the offset U when the pipe material is bent by the die rotating mechanism of the present embodiment and the conventional die mechanism.
In this embodiment, the material is STKM11A, an outer diameter of 25.4 mm and an inner diameter of 22.2 mm are to be bent, and both mechanisms have an inner diameter of a bearing portion of the die of 25.6 mm and a radius of curvature of a peripheral surface of the die. Was set to 30 mm, and approach V was set to 30 mm, and bending was performed.

As is apparent from FIG. 3, according to the die turning mechanism of the present embodiment, a small bending radius can be realized while setting an offset U smaller than that of the conventional die mechanism. Further, when comparing the surface of the processed tube material, even if the offset U becomes large, the rate of occurrence of “wrinkles” is smaller in the die rotating mechanism of the present embodiment, and the difference increases as the pushing speed of the tube material increases. It was remarkable.
That is, a smaller bending radius can be obtained with an offset U smaller than that of the conventional die mechanism, and stable and highly accurate bending can be realized.

[0025]

According to the present invention, the "die turning mechanism in the push-through bending apparatus" has the following effects by having the above-described structure. The invention of claim 1 comprises a guide cylinder through which a tube material or the like is inserted while being held, and a die which holds a part of the tube material or the like penetrating the guide cylinder by a bearing portion. In a device that performs bending by pushing pipes etc. through a guide cylinder and a die with the center of the bearing part relatively offset, the die is held rotatably by a die holder and the bearing part of the die is Bending with a bending radius smaller than that of the conventional die mechanism by positioning the annular projecting part provided on the die and the sending-out portion of the guide cylinder by positioning Processing can be performed stably and with high accuracy. The invention of claim 2 is
In the invention of claim 1, the condition that the surface of the die including the bearing portion is perpendicular to the axial direction of the pipe material passing through the bearing portion is realized by a simple means, and an ideal bending condition by the die is constituted.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a die rotating mechanism according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the die rotating mechanism in a state where an offset is set and bending of a tube is being performed.

FIG. 3 is a graph showing a change in a bending radius with respect to an offset when a pipe material is bent under substantially the same conditions by the die rotating mechanism of the embodiment and a conventional die mechanism.

FIG. 4 is a sectional view (A) of a conventional die mechanism applied to a press-through bending apparatus, and a front view (B) of a die side.

FIG. 5 is a cross-sectional view showing details of a configuration of a die mechanism.

FIG. 6 is a cross-sectional view of the die mechanism in a state where an offset is set and bending of a tube is being performed.

[Explanation of symbols]

1,51: die, 1a, 51a: annular projection, 1b, 51b: bearing, 1c: cylindrical inner peripheral surface, 2,52: die holder, 3,53
... Guide cylinder, 3a ... Spherical curved surface, 53a ... Control curved surface, 60 ... Tube, 70 ... Drive base, C1 ... Center of spherical curved surface of die, C2 ... Center of bearing part of die, Rp ...
Bending radius of tube material, S ... surface including bearing part of die,
U: offset, V: approach, Δy, Δy ': deviation of the center of the bearing part due to rotation of the die.

Claims (2)

[Claims] 1. A guide cylinder through which a tube, a shaped member or a solid material (hereinafter referred to as a "tube") is inserted while being held, and a part of the tube, etc. penetrating the guide cylinder is held by a bearing portion. A device for performing bending by pushing a tube or the like through the guide cylinder and the die in a state where the center axis of the guide cylinder and the center of the bearing portion of the die are relatively offset from each other. Bending device ''), the peripheral side surface is formed as a spherical curved surface having a center on the insertion port side of the pipe material etc. from the center of the bearing part, and passes through the center of the bearing part on the insertion port side of the pipe material etc. A die having an annular projection integrally formed with a cylindrical inner peripheral surface having a central axis defined by a straight line perpendicular to a surface including the bearing portion, and a spherical curved surface of the die. And a die holder for holding the die in opposition to the guide cylinder, and having a center on the center axis of a through-hole such as a pipe material around a delivery port for the pipe material and a maximum diameter. A die rotating mechanism in a push-through bending apparatus, wherein a portion is constituted by a guide cylinder provided with a spherical curved surface portion which abuts against an annular protrusion of the die. 2. A die according to claim 1, wherein a moving means is provided for moving the die holder and / or the guide cylinder in a direction in which the tube material is inserted, so that the distance between the die holder and the guide cylinder can be adjusted. Rotating mechanism.