JP2012040589A - Method and device for manufacturing deformed cross-section tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable forming at extremely low forming load by roll forming to make a facility compact and facilitate cost reduction and reduce surface roughness of a formed material since a contact area of a forming roll with the formed material is set smaller than a press die and higher contact pressure is applied, so as to obtain a deformed cross-section tube having better surface quality.SOLUTION: In this method for manufacturing the deformed cross-section tube, cold roll forming of a portion in the longitudinal direction of the formed material 100 made of a tube is performed by using upper, lower, right and left forming rolls 1, 2, 3, 4 arranged in a forming roll stand 10 to form a square-shaped cross section, so as to obtain the deformed cross-section tube. While movement 20 of the formed material 100 or the forming roll stand 10 is performed in the formed material longitudinal direction, a roll gap of the forming rolls 1, 2, 3, 4 is changed.

Description

  The present invention relates to a method and an apparatus for manufacturing a modified cross-section tube in which a part of a length of a tube (metal tube such as a steel tube) is formed into a square (square or rectangular) cross-sectional shape to form a modified cross-section tube.

  Tubes having different cross-sectional shapes in the tube length direction are referred to as irregular cross-section tubes. As a forming method from a tube (a circular tube or a tube having a uniform non-circular (elliptical, polygonal, etc.) cross-sectional shape in the longitudinal direction) to a deformed cross-section tube, the tube body is loaded with hydraulic pressure in the tube body. There is known a method of press-molding with a mold having a predetermined shape (Patent Documents 1 to 3). In addition, although the roll forming method which makes a pipe | tube full length a square tube (a fixed square cross-sectional shape) is well-known (for example, patent document 4), the example of manufacture of the irregular cross-section pipe which uses a part of pipe | tube as a square tube by roll forming method. Is not found.

JP 55-77934 A JP 55-55819 A Japanese Patent Laid-Open No. 8-90097 JP 2006-150377 A

  Conventionally, in order to obtain a modified cross-section tube from the tube, the tube was press-molded with a mold having a predetermined shape while applying a hydraulic pressure to the tube, but a press molding device and a hydraulic load device are required. There was a problem that it was difficult to reduce the cost because the equipment had to be large.

The present invention made to solve the above problems is as follows.
(1) An irregular cross section in which a part of the longitudinal direction of the material to be molded, which is a pipe, is cold and roll-formed into a square cross section with upper, lower, left and right molding rolls arranged on a molding roll stand. A method for manufacturing a modified cross-section pipe, wherein the roll gap of the forming roll is changed while moving the forming material or the forming roll stand in the longitudinal direction of the forming material.

(2) The method for manufacturing a modified cross-section pipe according to (1), wherein the movement of the molding material or the molding roll stand is a reciprocating movement.
(3) The deformed cross-section tube according to (1) or (2), wherein the roll forming is performed in a state in which a tube end deformation restraining cored bar is attached to both longitudinal ends of the molding material. Production method.

(4) Any of the above (1) to (3), wherein a steel pipe having a tensile strength of 980 MPa or more is used as the material, and a corner portion outer surface radius of curvature of the final molded product is 2.5 times or more of a wall thickness. The manufacturing method of the irregular cross-section pipe | tube as described in any one.
(5) An apparatus for manufacturing a deformed cross-section tube that forms a part of a longitudinal direction of a material to be formed of which a material is a tube into a square cross-sectional shape to form a deformed cross-section tube, and a support unit that supports the material to be formed; Forming roll stand with upper, lower, left and right forming rolls that roll-form a part in the longitudinal direction of the material to be formed into a square cross-sectional shape, and movement to reciprocate the material or forming roll stand in the length direction of the material to be formed An apparatus for manufacturing a modified cross-section pipe, comprising: a biasing means; a gap adjusting means for changing a roll gap of the forming roll; and a gap adjusting driving means for driving the gap adjusting means.

  (6) A passage sensor that detects a specific part passage time of the molding material or the molding roll stand, a gap sensor that measures a roll gap of the molding roll, and a control start point of the specific part passage time detected by the passage sensor As a control unit, which performs preset control of the processing position via the moving biasing means, and feedback-controls the roll gap at the processing position via the gap adjusting drive means using the measured value of the roll gap by the gap sensor. And the manufacturing apparatus of the irregular cross-section pipe as described in said (5) characterized by having.

  (7) The apparatus for manufacturing a modified cross-section pipe according to (5) or (6), further including a tube end deformation constraining metal core attached to both longitudinal ends of the molding material.

  According to the present invention, since it is formed by roll forming, it can be formed with a forming load that is remarkably low (for example, about 1/10) as compared with conventional press forming, so that the equipment can be made compact and cost reduction is easy. It is. In addition, since the forming roll has a smaller contact area with the material to be molded and higher surface pressure acts, the surface roughness of the material to be molded can be reduced, and a deformed cross-section tube with better surface quality can be obtained. can get.

(A) schematic overall view and (b) partial sectional view showing an example of an embodiment of the present invention Front view showing the forming roll stand of FIG. 1A is a schematic plan view of a molding process, and FIG. 1B is a schematic diagram of a predetermined pass schedule example used in the embodiment. Fig. 3 (b) shows the details of the first step. (A) Transition diagram of upper and lower roll gaps and (b) Cross-sectional view of vertical forming process The top view which shows one example (different from the example of the above-mentioned figure) of embodiment of this invention The top view which shows one example (different from the example of the above-mentioned figure) of embodiment of this invention The top view which shows one example (different from the example of the above-mentioned figure) of embodiment of this invention

  Hereinafter, the present invention will be described with reference to FIGS. In the present invention, as shown in FIG. 1, upper and lower, left and right forming rolls 1, 2, 3, 4 is a method of manufacturing a modified cross-section tube that is formed into a cross-section tube by roll forming into a square cross-sectional shape, and the forming rolls 1, 2, 3, and 4 are moved while moving the forming material 100 in the longitudinal direction of the forming material 100. The roll gap is changed. Further, instead of moving the molding material 100, the molding roll stand 10 may be moved 20.

  The reason why roll forming is performed cold (from room temperature to about 100 ° C.) is that there is a problem when performing hot forming. ・ Water cooling is required for forming stand durability (shaft, bearing, etc.). This is because it is necessary to deal with the thermal shock of the forming roll, and to cope with a change in the forming gap due to thermal expansion, and the equipment becomes large. Furthermore, it is for avoiding the deterioration of the surface property due to scale generation.

  Thereby, a part of the longitudinal direction of the material to be molded 100 (for example, a part excluding both ends in the longitudinal direction) can be formed into a square cross-sectional shape. However, if the molding is to be completed during only one-way (= 0.5 reciprocation) movement, depending on the strength of the material and the required molding amount, the material to be molded 100 will buckle during roll forming and the target shape will be Since the movement may not be obtained, the movement 20 is preferably a reciprocating movement of one or more reciprocations.

As a supporting means for supporting the material to be molded 100, a tube bottom guide roll 30 (FIGS. 3 and 5) for supporting the tube bottom, a fixed tube end guide 40 (FIG. 6) for supporting both ends of the tube, or a movable tube. An end guide 40A (FIG. 7) or the like can be used. The tube bottom guide roll 30 and the movable tube end guide 40A may be used in combination (FIG. 5).
The forming roll stand 10 holds upper, lower, left and right forming rolls 1, 2, 3, and 4. The roll rotation axes of the forming rolls 1, 2, 3, and 4 are arranged in the same plane orthogonal to the longitudinal direction of the molding material 100 (FIG. 2). The forming roll stand 10 includes, for example, screw-type gap adjusting means 1A, 2A, 3A, 4A for changing the roll gap of the forming rolls 1, 2, 3, and 4 (FIG. 2). The gap adjusting means 1A, 2A, 3A, 4A may be driven by a motor-type gap adjusting driving means 18, for example.

Examples of the moving urging means 16 for moving 20 the molding material 100 in the longitudinal direction of the molding material include a drive cylinder 70 using a movable tube end guide 40A as a cylinder rod (FIGS. 5 and 7).
Further, when the molding material stand 100 is fixed and the molding roll stand 10 is moved 20, both the tube ends of the molding material 100 are supported by a fixed-type tube end guide 40, while the molding roll stand 10 is The movement 20 may be urged by the drive cylinder 70 as supported by the guide rail 60 (FIG. 6).

In addition, it is preferable to perform the roll forming in a state where the pipe end deformation restraining core 50 is attached to both ends so that the both ends in the longitudinal direction of the material to be molded 100 are not deformed by any moment. (FIG. 7).
In order to carry out the present invention more efficiently and with higher accuracy, an apparatus for manufacturing a modified cross-section tube according to the present invention is, for example, as shown in FIG. (For convenience, these generic names are referred to as objects to be moved.) Are detected by a passage sensor 14 that detects the passage time of a specific part, a gap sensor 12 that measures the roll gap of the forming rolls 1, 2, 3, and 4, and the passage sensor 14. The processing position is preset via the movement urging means 16 with the movement target passing through a specific part as a control starting point, and the measured value of the roll gap by the gap sensor 12 is used to drive the gap adjustment drive means 18. It is preferable that the apparatus has a control unit 22 that feedback-controls the roll gap at the processing position.

Examples of the specific part of the moving object include a pipe end part when the moving object is a molding material, and a part near the roll axis position when the moving object is a forming roll stand. In order to facilitate the passage time detection of the specific part by the passage sensor 14, an appropriate marker may be fixed to the specific part.
In the preset control via the movement urging means 16, the movement urging means 16 (for example, the drive cylinder 70 in FIG. 5) to be operated is operated along a predetermined reciprocating motion sequence, and the material to be molded is controlled. The processing position which is the forming roll position point on the longitudinal position coordinate axis is associated with the time point on the time coordinate axis from the control starting point.

  The predetermined reciprocating motion sequence is information that prescribes the relationship between the speed and time of the forward / backward movement of the piston rod of the drive cylinder 70, which is created in advance based on a molding processing plan from the material shape to the target molding shape, They are stored in the control unit 22 in the form of mathematical expressions or tables. The control unit 22 generates a control signal for operating the drive cylinder 70 in accordance with the predetermined reciprocating operation sequence, and transmits the control signal to the drive cylinder 70 to operate the control cylinder 22 so that the machining position is on the time coordinate axis from the control start point. Move with.

  In the feedback control via the gap adjusting drive means 18, the gap adjusting drive means 18 to be operated (for example, a screw drive motor for driving the screw type gap adjusting means 1A, 2A, 3A, 4A in FIG. 2). Is operated so that the roll gap at the machining position does not deviate from the predetermined pass schedule. At this time, the measured value of the roll gap by the gap sensor 12 is used, and this measured value is added to the predetermined pass schedule. Compare the target value of the corresponding roll gap with, calculate the amount of deviation of the measured value relative to the target value, and operate the screw drive motor 18 so that the amount of deviation becomes zero. Control the gap.

  The predetermined pass schedule is information preliminarily created based on a forming process plan from a raw material shape to a target forming shape, and prescribing a transition (time-dependent change) of a roll gap at a processing position. It is stored in the control unit 22. The processing position can be moved on the time coordinate axis from the control starting point by preset control as described above. The control unit 22 generates an operation signal in which the deviation amount becomes zero, transmits the operation signal to the screw driving motor 18, and operates this to increase or decrease the roll gap at the machining position. If the amount of deviation is zero, nothing is done.

It should be noted that the same preset control as that for the processing position is performed on the roll gap when the actual forming process deviates from the predetermined pass schedule due to disturbance or the like. Although molding defects will be caused, according to the feedback control, occurrence of such molding defects can be suppressed.
As the gap sensor 12, for example, a linear encoder, a laser distance meter, or the like can be preferably used. As the passage sensor 14, for example, a laser-Doppler type, an ultrasonic type or the like can be preferably used. The control unit 22 can be configured using a normal personal computer.

  The example of the predetermined forming pass schedule shown in the schematic diagram of FIG. 3B is an example of forming a material circular tube into a deformed cross-sectional tube having a rectangular cross-sectional shape, and a roll gap (abbreviated in the processing position). The gap) is indicated by a solid line between the top and bottom and a dotted line between the left and right. Here, the object to be moved is the material 100 (FIG. 3 (a)). The reciprocation at the movement 20 is 1.5 reciprocations, with 1 reciprocation at the 1st step (forward rotation) and 2nd step (reverse rotation), and the remaining 0.5 reciprocation at the 3rd step (forward rotation). Here, forward rotation and reverse rotation indicate the direction of rotation of the forming roll (forward rotation, reverse rotation). In addition, in the movement 20 of FIG. 3 (a), apart from acceleration / deceleration, the movement speed at constant speed is substantially constant over the entire region from the first step to the third step.

The gap between the left and right shifts from the state of wide opening to the state where the molding rolls 3 and 4 are in light contact with the molding material 100 at the pipe setting stage, and then maintains the same state throughout the entire area from the 1st step to the 3rd step. Next, in the pipe take-out stage, the state returns to the wide open state.
The gap between the upper and lower sides shifts from the wide open state to the state where the forming rolls 1 and 2 are in light contact with the material to be formed 100 at the pipe setting stage. Next, from the 1st step to the 3rd step, every step changes along the reverse hat-shaped fold line, and the bottom of the reverse hat-type changes so as to have a smaller gap than the same part of the previous step, then pipe removal At the stage, it returns to the state of wide open.

4A shows the details of the first step of FIG. 3 as (a), and FIG. 4B shows a cross-sectional view of the molding process corresponding to points A, B, C, and D of (a).
The left horizontal portion of the inverted hat-shaped broken line in FIG. 4A is a region where the gap does not change, and the processing position is within the end non-forming region on the forming processing start end side. At point A in this region, as shown in the corresponding cross-sectional view of FIG. 4B, the molding rolls 1 and 2 are in light contact with the molding processing start end side of the molding material 100 being stopped.

The left oblique line connected to the left horizontal portion is a region where the gap is gradually narrowed, and the processing position is in the gradually changing region where the cross-sectional shape gradually changes from the material cross-section side to the deformed cross-section side. At point B in this region, as shown in the corresponding cross-sectional view of FIG. 4B, the molding material 100 moving in the forward rotation direction is gradually pressed by the molding rolls 1 and 2.
The central horizontal portion connected to the left oblique line portion is a region where the gap does not change, and the processing position is in a regular rectangular cross section (in this example, a rectangular cross section) forming region. At point C in this region, as shown in the corresponding cross-sectional view of FIG. 4 (b), the molding material 100 moving in the forward rotation direction is pressed by the molding rolls 1 and 2 with the gap fixed. It is in.

The right oblique line connected to the central horizontal portion is a region where the gap gradually widens, and the processing position is in the gradually changing portion region where the cross-sectional shape gradually changes from the deformed cross section side to the material cross section side.
The right horizontal portion connected to the right oblique line portion is a region where the gap does not change, and the processing position is within the end non-forming region on the forming processing end side. At point D in this region, as shown in the corresponding cross-sectional view of FIG. 4 (b), it is in a state immediately before releasing the pressing of the forming rolls 1 and 2 against the forming material 100 moving in the forward rotation direction.

By using the above manufacturing apparatus, it is possible to control the processing position of the material to be molded and the roll gap therewith with high accuracy, and it is possible to manufacture the irregular cross-section tube with high efficiency and high dimensional accuracy.
The moving speed at a constant speed of the moving object is preferably set to 10 m / min or less because if the speed is too high, molding defects such as dimensional shape defects due to roll slip or the like easily occur in the gradually changing portion region. Also, when the roll gap is gradually narrowed, if the gap reduction rate is too high, it is likely to cause molding failure such as roll slip or dimensional shape failure due to gap control failure in the corresponding gradual change region. The following is preferable. Also, if the gap change amount in one step (= the left horizontal portion gap value-the central horizontal portion gap value in the inverted hat-shaped polygonal line) is too large, molding defects such as buckling will occur in the gradually changing portion region. Since it is easy to occur, it is preferable to be 20 mm or less.

  By the way, when a steel pipe having a tensile strength of 980 MPa or more is used as the material, if the corner portion outer surface radius of curvature of the final molded product is less than 2.5 times the wall thickness, processing cracks, bending inside bending, delayed fracture, etc. The molding defect is likely to occur. Therefore, in the present invention, when a steel pipe having a tensile strength of 980 MPa or more is used as the material, it is preferable that the corner portion outer surface radius of curvature of the final molded product is 2.5 times or more the wall thickness.

  As an example, the apparatus shown in FIG. 1 is used, and the material steel pipe (element tube) shown in Table 1 is used as a material to be molded, and roll forming is performed according to the reciprocation pass schedule shown in Table 1, and the final forming shape shown in Table 1 An irregular cross-section tube was manufactured. Some of the molding materials were fitted with pipe end deformation restraining cores at both ends. The moving object was a material to be molded, the moving speed at a constant speed was 3 m / min, the gap reduction speed was 10 mm / sec, and the gap change amount in one step was 10 mm.

  Table 1 shows the results of examining the presence or absence of molding defects at this time. It can be seen that a modified cross-section tube could be manufactured according to the present invention. However, when one-way movement (No. 4) or when using a pipe with a tensile strength (TS) of 980 MPa or more and the corner part outer surface radius of curvature of the final molded product is less than 2.5 times the wall thickness ( In No.8 and No.9), molding defects occurred.

  As a comparative example, when forming the same raw tube as No. 1 in the example into a deformed cross-section tube having the same shape, the tube is press-molded with a mold having a predetermined shape while applying a hydraulic pressure to the tube. Tried how to do. In the comparative example, although a desired product shape was obtained, the facilities became large, and the cost was twice or more that of the example.

1,2,3,4 Forming rolls (1,2: top and bottom, 3,4: left and right)
1A, 2A, 3A, 4A Gap adjustment means (screw type)
10 Forming roll stand
12 Gap sensor
14 Pass sensor
16 Movement biasing means
18 Gap adjustment drive means (screw drive motor)
20 Movement (Movement of molding material or molding stand along the longitudinal direction of the molding material)
22 Control unit
30 Tube bottom guide roll
40 Pipe end guide (fixed type)
40A Pipe end guide (movable)
60 guide rail
70 Drive cylinder
100 Molded material

Claims (7)

  Manufacture of odd-shaped cross-section pipes that are partly formed in the longitudinal direction of the material to be molded, which is a pipe, and are formed into a square cross-section by roll forming into a square cross-sectional shape with upper, lower, left and right molding rolls arranged on a molding roll stand A method for producing a modified cross-section tube, wherein the roll gap of the molding roll is changed while moving the molding material or the molding roll stand in the longitudinal direction of the molding material.   The method for manufacturing a modified cross-section tube according to claim 1, wherein the movement of the molding material or the molding roll stand is a reciprocating movement.   The method for producing a modified cross-section pipe according to claim 1 or 2, wherein the roll molding is performed in a state in which a tube end deformation restraining metal core is attached to both longitudinal ends of the material to be molded.   The steel pipe having a tensile strength of 980 MPa or more is used as the material, and the corner portion outer surface radius of curvature of the final molded product is set to be 2.5 times or more of the wall thickness. Manufacturing method of irregular cross-section tube.   An apparatus for manufacturing a deformed cross-section tube that forms a part of a longitudinal direction of a material to be formed of which a material is a tube into a square cross-sectional shape into a deformed cross-section tube, and a support means for supporting the material to be formed, and the material to be formed A forming roll stand provided with upper, lower, left and right forming rolls that roll-form a part of the longitudinal direction into a square cross-sectional shape, and a moving urging means for reciprocating the molding material or the molding roll stand in the molding material length direction An apparatus for manufacturing a modified cross-section pipe, comprising: a gap adjusting unit that changes a roll gap of the forming roll; and a gap adjusting driving unit that drives the gap adjusting unit.   With a passage sensor that detects a specific part passage time of the molding material or a molding roll stand, a gap sensor that measures a roll gap of the molding roll, and a specific part passage time detected by the passage sensor as a control starting point, A control unit that performs preset control of the processing position via the moving biasing means, and feedback-controls the roll gap at the processing position via the gap adjusting drive means using the measured value of the roll gap by the gap sensor. An apparatus for manufacturing a modified cross-section tube according to claim 5, comprising:   The apparatus for manufacturing a modified cross-section pipe according to claim 5 or 6, further comprising a pipe end deformation restraining core metal attached to both ends of the molding material in the longitudinal direction.

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