WO2011055408A1

WO2011055408A1 - Pipe bending device with assist function and bending method

Info

Publication number: WO2011055408A1
Application number: PCT/JP2009/005864
Authority: WO
Inventors: 齋藤幸司; 藍原武夫; 佐藤博之
Original assignee: 株式会社太洋
Priority date: 2009-11-05
Filing date: 2009-11-05
Publication date: 2011-05-12
Also published as: JPWO2011055408A1; CN102596442B; CN102596442A; JP5044045B2

Abstract

Disclosed are a pipe bending device and bending method, which are capable of executing the bending method of any of a pressing force applying system, a tensile resistance force applying system, and a no-load tracking system. Specifically disclosed is a pipe bending device (1) which is configured by a bending die (2) for winding a pipe (9) around the outer peripheral surface thereof to perform bending, a chuck (7) configured in such a manner as to grip a rear end section (9d) of the pipe, a feed positioning device (8) configured in such a manner as to allow movement in the axial direction of the rear end side section of the pipe (9) that holds the chuck (7) and is gripped by the chuck (7), a feed servo motor, a bending servo motor for supplying rotational driving force to the bending die (2), a ball screw (5) configured in such a manner as to be able to move the feed positioning device (8) and the chuck (7) in a predetermined direction by converting the output torque of the feed servo motor into the thrust of a slider (5b), and a control device for controlling the output torque of the feed servo motor.

Description

Pipe bending apparatus with assist function and processing method

TECHNICAL FIELD The present invention relates to a rotating and bending apparatus and a processing method for a metal pipe, and in particular, an assist capable of performing a rotating and bending process while pressing or pulling a rear end portion of a grasped metal pipe in an axial direction. The present invention relates to a pipe bending apparatus and a processing method with added functions.

As a metal pipe bending apparatus, a pipe bending apparatus 51 (rotary pull bending apparatus) as shown in FIG. 6 is widely used. The pipe bending apparatus 51 includes a rotatable bending mold 52, a clamp 53 that clamps and fixes the distal end portion 9a of the pipe 9 between the bending mold 52, and a portion of the pipe 9 that is bent. A pressure die 54 that presses the bending portion 9b against the bending die 52 and a chuck 57 that holds the rear end portion 9d of the pipe 9 are provided. The bending die 52 and the clamp 53 are moved in a predetermined direction (clockwise direction in FIG. 6). ), The pipe 9 is bent along the outer peripheral surface of the bending die 52 while pulling the tip end portion 9a of the sandwiched pipe 9.

In addition, in the conventional pipe bending apparatus 51 as shown in FIG. 6, the fracture | rupture by thinning will arise in the outer part of the bending part 9b of the pipe 9, or a wrinkle will arise in the inner part of the bending part 9b. In addition, there is a problem that the bent portion 9b is flattened.

Therefore, as a countermeasure for avoiding such a problem, when the bending die 52 is rotated, a pressing force applying means 55 (bending portion) that pushes the rear end side portion 9c of the pipe 9 forward (in the direction of the bending die 52). Pipe bending apparatus (Japanese Patent Application Laid-Open No. 2008-302377, Japanese Patent Application Laid-Open No. 2006-315077, Japanese Patent Application Laid-Open No. 2003-290839, Japanese Patent Application Laid-Open No. 2003-290839, Japanese Patent Application Laid-Open No. 2003-290839) -9080838 etc.) or, conversely, the tensile resistance applying means 56 (the direction opposite to the bending die 52) for pulling the rear end side portion 9c of the pipe 9 backward (the direction opposite to the bending die 52) acts. Pipe bending apparatus (means for sending in the direction of the bending die 52 while applying a load) (JP 2009-106965, JP 11-267765, etc.) There has been an existence.

JP 2009-106965 A JP 2009-045631 A JP2009-012068 JP2009-012067 JP 2009-012022 A JP2008-302380 JP2008-302377 JP2008-229643 JP 2008-126268 A JP2007-319916 JP2007-090422 JP 2006-326637 A JP 2006-315077 A JP 2006-289488 A JP 2006-116586 A JP 2006-088178 A JP 2006-043765 A JP-A-2005-161342 JP-A-2005-161332 JP-A-2005-161331 JP-A-2005-161325 JP-A-2005-161324 JP 2003-290839 A JP 2003-290838 A JP 2001-047141 A JP-A-11-267765 JP 09-239450 A Actual opening 07-009518 Actual opening 07-009517

The conventional pipe bending apparatus 51 includes the pipe bending apparatus provided with the pressing force applying means 55 (which can perform the bending process of the pressing force applying method) and the tensile resistance adding means 56 as described above. There is a pipe bending apparatus (which can implement a bending method of adding a tensile resistance force type), and the bending is performed by rotating the bending die 2 without pushing or pulling the rear end side portion 9c of the pipe 9. There is known a pipe bending apparatus that can perform a method of performing rotary pull bending by simply causing the chuck 7 to follow the rear end side portion 9c pulled in the direction of the mold 52 (unloading following bending method). ing.

Currently, the pipe bending equipment supplied to the market is a “dedicated machine” specialized for only one of the above methods. There is no pipe bending apparatus that can implement any bending method of the no-load following method. This is considered due to the following reasons.

The pressing force applying means 55 employed in the conventional pipe bending apparatus uses a hydraulic mechanism, and controls the flow rate of oil (the speed of the pushed-out plunger) flowing into the hydraulic cylinder (specifically, In this case, by controlling the plunger speed so as to be the moving speed of the rear end side portion 9c of the pipe 9 × coefficient e (e> 1)), a bending process using a pressing force is realized. On the other hand, when the bending process of the tensile resistance addition method is performed, the value of the coefficient e by which the moving speed of the rear end portion 9c of the pipe 9 is multiplied is made smaller than 1 (e <1). Even if such control is performed by a mechanism, a tensile resistance force cannot be added. Further, the tensile resistance applying means 56 employed in the conventional pipe bending apparatus can add a tensile resistance but cannot control the size thereof. From such circumstances, it is considered that the pipe bending apparatus provided with both the pressing force applying means 55 and the tensile resistance applying means 56 has not yet been put into practical use.

Also, the pipe bending apparatus that can perform the no-load following bending method has the following problems. In the case where the rotary bending process is performed by the pipe bending apparatus 51 as shown in FIG. 6, when the bending mold 52 is rotated, the rear end side portion 9 c and the rear end portion 9 d of the pipe 9 are bent. Accordingly, the chuck 57 (and a device for supporting the rear end portion 9d) that holds the rear end portion 9d also moves in accordance with the movement of the rear end portion 9d. It is necessary to feed forward and follow the rear end 9d.

At this time, in order to send the chuck 57 in accordance with the movement of the rear end portion 9d without applying a load to the pipe 9, the rear end portion 9d (or the chuck 57 or the same) generated in one bending process is performed. It is necessary to accurately grasp the movement amount (or stop position) of the device that supports the device.

However, since the amount of movement of the rear end 9d and the like that occurs in one bending process depends on the amount of elongation of the pipe that occurs in one bending process, it is impossible to obtain an accurate value only by calculation. . Therefore, in the conventional pipe bending apparatus 51, when the movement amount (or stop position) of the rear end portion 9d (or the chuck 57 or a device supporting the same) is to be grasped, the rear end portion 9d is chucked. In a state where the pipe 9 is not gripped by 57, trial bending is performed on the pipe 9 under predetermined conditions (for example, trial bending angle: 90 °, number of times of bending: 1 time), and the movement amount of the rear end 9d at that time (trial The amount of bending movement) is measured, the elongation (elongation per 1 degree of bending) is calculated from the measured value of the trial bending movement, and the amount of movement at the actual bending angle is calculated from the calculated elongation rate. (Actual movement amount) and stop positions of the rear end 9d and the like are calculated.

However, if it is necessary to perform a series of preparatory operations (trial bending, measurement of trial bending movement amount, calculation of actual movement amount) as described above before actual bending, it is very complicated and time-consuming. There is a problem.

The present invention has been made to solve the above-described problems, and includes an element that functions as a pressing force adding means and a tensile resistance adding means. In a single bending apparatus, It is possible to execute any bending method of pressing force application method, pulling resistance force addition method, and no-load following method. An object of the present invention is to provide a pipe bending apparatus and a processing method capable of omitting preparatory work such as bending, measurement of a test bending movement amount, and calculation of an actual movement amount.

A pipe bending apparatus according to the present invention includes a bending die that performs bending by winding a pipe to be processed around an outer peripheral surface, a chuck configured to hold a rear end portion of the pipe, and a chuck, A feed positioning device configured to be movable in the axial direction of the rear end side portion of the pipe held by the chuck, a feed servo motor, a bending servo motor for supplying a rotational driving force to the bending die, and a feed positioning device A ball screw configured to be able to move the feed positioning device and the chuck in a predetermined direction by converting the output torque of the feed servo motor into the thrust of the slider in the axial direction of the shaft; And a control device for controlling the output torque of the feed servo motor.

In the pipe bending method of the no-load following method according to the present invention, when the chuck is in a free state, the minimum torque required to move the feed positioning device and the chuck in the direction of the bending die is It is characterized in that bending is performed by outputting from a feed servo motor to a ball screw. In this method, after the rotation of the bending mold is stopped, the output torque of the feed servo motor is limited to 0 by the torque limiting function and attenuated to 0, and after a predetermined time, the accumulated pulses of the feed servo motor It is preferable to cancel the accumulated pulse by issuing a feed backward / reverse command comprising the same number of pulses from the control device.

In the pipe bending method of the pressing force application method according to the present invention, when the chuck is in a free state, the minimum torque required to move the feed positioning device and the chuck in the direction of the bending die is The bending is performed by adding torque corresponding to the pressing force to be applied to the pipe during bending and outputting torque from the feed servo motor to the ball screw. In this method as well, after the rotation of the bending mold is stopped, the output torque of the feed servo motor is limited to 0 by the torque limiting function and attenuated to 0, and after a predetermined time, the accumulation of the feed servo motor is stopped. It is preferable to read the pulses and issue a feed backward / reverse command comprising the same number of pulses from the control device to eliminate the accumulated pulses. Further, when the output torque of the feed servo motor is limited and attenuated to 0, it is preferable to divide the required time into at least two stages and drop the output torque in stages.

According to the pipe bending method of the tensile resistance addition method according to the present invention, the feed stop target position of the chuck is set behind the feed start position, and when the controller issues a forward bending command to the bending servo motor, the feed servo It is characterized in that bending is performed by issuing a feed backward command to the motor. In this method, after the rotation of the bending mold is stopped, the output torque of the feed servo motor is limited to 0 by the torque limiting function and attenuated to 0, and after a predetermined time, the accumulated pulses of the feed servo motor It is preferable to cancel the accumulated pulses by issuing a feed forward command consisting of the same number of pulses from the control device. Further, when the output torque of the feed servo motor is limited and attenuated to 0, it is preferable to divide the required time into at least two stages and drop the output torque step by step.

The pipe bending apparatus according to the present invention includes a ball screw that can function as both a pressing force applying unit and a tensile resistance adding unit. Any of the bending method of the resistance force addition method and the no-load following method can be executed. Further, in the case of carrying out a no-load following type bending method, it is possible to omit preparation work such as trial bending, measurement of trial bending movement, calculation of actual movement, and the like.

In addition, according to the pipe bending method according to the present invention, it is possible to suitably control the pressing force applied to the pipe during bending or the magnitude of the tensile resistance, and the outer portion of the pipe bending portion. It is possible to suitably avoid the problem of breakage due to thinning that is likely to occur in the case of, and generation of wrinkles in the inner part of the bent part and flattening of the bent part. Furthermore, the impact that can occur when releasing torque can be reduced, problems such as damage to the components can be avoided, precise positioning can be performed, and bending accuracy can be improved.

FIG. 1 is a diagram illustrating main components of a pipe bending apparatus 1 according to the first embodiment. FIG. 2 is an explanatory diagram of a processing method using the pipe bending apparatus 1 according to the first embodiment. FIG. 3 is an explanatory diagram of a bending method using a no-load following method according to the second embodiment. FIG. 4 is an explanatory diagram of a no-load following type bending method using a conventional pipe bending device 51. FIG. 5 is an explanatory diagram of a bending method of a tensile resistance addition method according to the fourth embodiment. FIG. 6 is a diagram showing the main components of a conventional pipe bending apparatus 51.

Hereinafter, embodiments of the “pipe bending apparatus” and the “pipe bending method” of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram showing main components of a pipe bending apparatus 1 according to the first embodiment of the present invention. In this figure, 2 is a bending die, 3 is a clamp, 4 is a pressure die, 5 is a ball screw, 7 is a chuck, and 8 is a feed positioning device.

The bending die 2 is formed with a round groove 2a having a shape corresponding to the diameter of the pipe 9 to be processed on the outer peripheral surface, and a round portion 2a extending in a circle and a straight portion 2b extending in a straight line. And is configured to be rotatable around the central axis of the round portion 2a by a driving force of a bending servo motor (not shown).

The clamp 3 is disposed at a position facing the straight portion 2b of the bending die 2 and presses the tip side portion 9a of the pipe 9 held between the straight portion 2b of the bending die 2 in the direction of the bending die 2. It is configured to sandwich and rotate integrally with the bending die 2.

The pressure die 4 is pulled and slid in accordance with the rotation of the bending die 2 while pressing the portion (bending portion 9 b) of the pipe 9 to be bent from the side of the pipe 9 toward the bending die 2. In accordance with the movement of the pipe 9, it is configured to move in the axial direction (the direction of arrow D in FIG. 1) of the rear end side portion 9 c (unprocessed portion) of the pipe 9.

The ball screw 5 includes a shaft 5a having a spiral groove (not shown) on the outer peripheral surface, and a slider 5b that has a key that engages in the spiral groove formed on the inner peripheral surface and is held so as not to rotate. By rotating the shaft 5a by applying a rotational driving force from a feed servo motor (rotational driving force source) (not shown), the slider 5b moves in the axial direction of the shaft 5a according to the amount of rotation. The output torque of the feed servo motor can be converted into the thrust of the slider 5b (thrust in the axial direction of the shaft 5a). In addition, the shaft 5a is supported in a direction in which the axis thereof coincides with the axial direction of the rear end side portion 9c of the pipe 9.

The chuck 7 is configured to hold the rear end portion 9 d of the pipe 9 and is held by the feed positioning device 8.

The feed positioning device 8 is connected to the slider 5b of the ball screw 5 and is configured to be movable in the axial direction of the rear end side portion 9c of the pipe 9. Therefore, by operating the ball screw 5 (by rotating the shaft 5a and moving the slider 5b in the axial direction of the shaft 5a), the feed positioning device 8 and the chuck 7 are connected to the rear end side portion 9c of the pipe 9. It is designed to move in the axial direction. Incidentally, the position control of the chuck 7 and the feed positioning device 8 by the operation of the ball screw 5 (movement start and stop positions, or movement amount control) is accurately performed by a control device (not shown). It has come to be. In addition, this control device has a function (torque limiting function) for limiting the output torque of the feed servo motor that applies rotational driving force to the ball screw 5 to a desired value (or within a range). The output torque can be suitably controlled.

The pipe bending apparatus 1 shown in FIG. 1 has the above-described configuration. When the bending die 2 is rotated, the rear end side portion 9c of the pipe 9 is moved by the feed positioning device 8 (and the chuck 7). A method of performing rotational pulling while pushing in the direction of the bending die 2 (pressing force-added bending method) and a rear end side portion 9c of the pipe 9 with the bending die 2 by the feed positioning device 8 (and chuck 7). Is a method of performing rotational pulling while pulling in the opposite direction (bending method of applying a tensile resistance force method), and rotating the bending die 2 without pushing or pulling the rear end side portion 9c of the pipe 9. A method of performing rotary pull bending by simply causing the chuck 7 and the feed positioning device 8 to follow the rear end side portion 9c pulled in the direction of the bending die 2 (bending method of no load following method) It is possible to carry out the door.

Also, there is a processing method for changing the amount of pressing force or tensile resistance force during one bending process (from the start to the end of a single pipe bending process). It can also be implemented. In addition, when a plurality of bending processes are performed on a plurality of portions of a single pipe, different processing methods are applied to the respective processing portions (for example, a certain portion of a bending method using a pressing force application method). It is also possible to implement a processing method, and to perform a bending resistance-added bending method or a no-load follow-up bending method in other portions).

Here, among the above-described processing methods using the pipe bending apparatus 1 of FIG. 1, a no-load following type bending method will be described as a second embodiment of the present invention. When performing the no-load following type bending method using the pipe bending apparatus 1 of FIG. 1, first, the clamp 3 and the chuck 7 are opened, and the bending die 2 and the pressure die 4 are respectively set to the starting positions. set. Specifically, as shown in FIG. 1, the bending die 2 is set so that the straight portion 2b coincides with the axial direction of the pipe 9, and the pressure die 4 is closer to the rear end 9d side of the pipe 9. Set to position.

Next, the pipe 9 is fed between the bending die 2, the clamp 3 and the pressure die 4, and sent until the rear end 9 d enters the innermost part in the chuck 7. When the rear end portion 9d hits the innermost portion of the chuck 7, the chuck 7 is tightened to firmly hold the rear end portion 9d.

Subsequently, the chuck 7 is moved to a feed start position S (a position where the bending portion 9b of the pipe 9 held by the chuck 7 comes into contact with an appropriate position of the bending die 2). The movement of the chuck 7 to the feed start position S is executed by operations of a control device, a servo amplifier (not shown), a feed servo motor, and the ball screw 5.

Specifically, a movement command (a number of movement command pulses proportional to the distance from the current position to the feed start position S) for moving the chuck 7 from the current position to the feed start position S is output from the control device to the servo amplifier. Then, the movement command pulse is integrated in the deviation counter of the servo amplifier. The servo amplifier supplies drive power to the feed servomotor in accordance with the movement command pulse accumulated in the deviation counter. The feed servo motor rotates by receiving driving power, and the ball screw 5 operates to move the chuck 7.

At this time, the number of feedback pulses proportional to the rotation speed of the feed servo motor is output from the encoder attached to the feed servo motor and input to the deviation counter of the servo amplifier. The feedback pulse input to the deviation counter subtracts the accumulation pulse (movement command pulse) of the deviation counter. When the accumulated pulse of the deviation counter becomes “0”, the power supply from the servo amplifier to the feed servo motor is stopped, and the feed servo motor and the ball screw 5 are stopped. As a result, the chuck 7 stops at the feed start position S.

In this embodiment, information on the current position of the chuck 7 (distance from the machine origin B to the current position of the chuck 7) is the rotation angle of the feed servo motor from the machine origin B to the current position (output from the encoder). Number of pulses) and the amount of movement per revolution of the feed servo motor.

When the movement of the chuck 7 to the feed start position S is completed, the clamp 3 is tightened, and the tip end portion 9a of the pipe 9 is clamped between the bending die 2 and fixed. When the pipe 9 is fixed, before the bending die 2 is rotated, the torque adjusted to a predetermined magnitude by the torque limiting function is output from the feed servo motor. The torque output here is such that when the chuck 7 is in a free state where the pipe 9 is not gripped, the feed positioning device 8 and the chuck 7 are moved in the direction of the bending die 2 by operating the ball screw 5. The minimum output (t1) required for this is set. Even if torque is output at this time, the bending die 2 is not rotating and the rear end 9d of the pipe 9 is not displaced, so the slider 5b, the feed positioning device 8 and the chuck 7 do not move.

The control device grasps the torque output of the feed servo motor from the current value output from the servo amplifier to the feed servo motor, and the output value of the torque of the feed servo motor is “t1” (or When it is confirmed in the control device that the tolerance has been reached, an angle from the control device to the servo amplifier of the bending servo motor is sent to the servo amplifier of the bending servo motor (the angle from the start position of the bending die 2 to the position when the bending is completed). Is sent to the servo amplifier of the feed servomotor, and the feed forward command pulse is proportional to the distance from the feed start position S of the chuck 7 to the feed stop target position K. ) Is issued.

In the present embodiment, information on the feed stop target position K of the chuck 7 (distance k from the machine origin B of the chuck 7; see FIG. 3) is obtained from the feed start position S (distance s from the machine origin B by the controller). ), A bending radius r, a set bending angle q, and a coefficient c. The coefficient c used here is “> 1”.

(Formula 1)
k = s− (2πr (q / 360)) c

When the bending forward rotation command and feed forward command are issued from the control device, the drive power is supplied from the servo amplifier of the bending servo motor, the bending servo motor rotates, and the drive power is supplied from the servo amplifier of the feed servo motor to feed. Servo motor rotates. Then, the bending mold 2 rotates in a predetermined direction as shown in FIG. As the bending mold 2 rotates, the pipe 9 sandwiched between the bending mold 2 and the clamp 3 is pulled in the rotation direction of the bending mold 2, and the bending portion 9 b extends along the outer peripheral surface of the round portion 2 a of the bending mold 2. The pipe 9 is wound and bent.

At this time, the rear end side portion 9c and the rear end portion 9d of the pipe 9 gradually move in the direction of the bending die 2 as the bending die 2 rotates, and the chuck 7 grips the rear end portion 9d. The feed positioning device 8 that holds this also gradually moves in the direction of the bending die 2 together with the rear end portion 9d. However, the feed positioning device 8 and the chuck 7 are connected to the bending die 2 by the ball screw 5. Since the minimum output torque t1 required for moving in the direction is applied, the feed positioning device 8 and the chuck 7 follow in a state in which almost no load is applied to the pipe 9.

When the rotation angle of the bending die 2 reaches the set angle (set bending angle q), the rotation of the bending die 2 is stopped and the bending process is completed. More specifically, when the bending servo motor that operates the bending die 2 rotates, the encoder attached to the bending servo motor outputs a number of feedback pulses proportional to the number of rotations of the bending servo motor, and the bending servo motor Input to the deviation counter of the servo amplifier. The feedback pulse input to the deviation counter subtracts the deviation counter accumulation pulse (bending command pulse). When the accumulated pulse of the deviation counter becomes “0”, the power supply from the servo amplifier to the bending servo motor is stopped and the bending servo motor is stopped.

When the bending servo motor stops and the bending die 2 stops rotating, the rear end side portion 9c, the rear end portion 9d of the pipe 9, the chuck 7, the feed positioning device 8, and the ball screw 5 are also stopped. However, at this time, the chuck 7 has not moved to the feed stop target position K (see FIG. 3), and the current position of the chuck 7 (first stop position F) is displayed in the deviation counter of the servo amplifier of the feed servo motor. 3 (2)) to the feed stop target position K, the number (α) of feed advance command pulses proportional to the distance f is accumulated. Therefore, due to these accumulated pulses (α), electric power is still supplied from the servo amplifier to the feed servomotor, and torque t1 is output from the feed servomotor. Therefore, in the present embodiment, after the bending servo motor is stopped, the output torque of the feed servo motor is limited and attenuated to “0” by the torque limiting function.

When the output torque of the feed servo motor becomes “0”, the thrust of the ball screw 5 acting on the chuck 7 and the feed positioning device 8 is lost, and the bending occurring in the pipe 9, the chuck 7, the feed positioning device 8 and the like is lost. Since the chuck 7 is opened, the chuck 7 slightly moves backward (in the direction opposite to the bending die 2) (final stop position G, see FIG. 3 (3)). For this reason, feed forward command pulses of a number (β) proportional to the amount of movement (distance g from the first stop position F to the final stop position G) are accumulated in the servo amplifier of the feed servo motor. Will be stacked on top.

Therefore, in the present embodiment, after the output torque of the feed servo motor is set to “0”, a predetermined time is set by the timer count up, and then the accumulated pulses (α + β) of the servo amplifier are read and are composed of the same number of pulses. A feed backward command (number of feed backward command pulses proportional to the distance (f + g) from the final stop position G of the chuck 7 to the feed stop target position K (α + β)) is issued from the control device, and is sent to the servo amplifier of the feed servo motor. It is designed to be entered.

The feed forward command pulse accumulated in the deviation counter of the servo amplifier and the input feed backward command pulse are opposite in the feed direction of the chuck 7, so the feed forward command pulse accumulated in the deviation counter is Subtracted by command pulse. Since the numbers of pulses coincide with each other, all the accumulated feed forward command pulses are subtracted (cancelled), and the accumulated pulses become “0”. As a result, power supply from the servo amplifier to the feed servo motor is stopped, and the feed servo motor is stopped. When the feed servo motor is stopped, the torque limit is released, the clamp 3 and the chuck 7 are opened, the pipe 9 is removed from the pipe bending apparatus 1, or only the clamp 3 is opened, and the next bending process is performed. Therefore, the pipe 9 is moved (positioning to the next feed start position is performed).

The no-load following type bending method in the present embodiment is executed in the above-described procedure, and is required in the no-load following type bending method using the conventional pipe bending apparatus 51 (see FIG. 6). A series of preparatory work (trial bending performed prior to actual bending, measurement of trial bending movement amount, calculation of actual movement amount, etc.) can be omitted.

This point will be described in detail. In the conventional no-load following type bending method using the pipe bending device 51, the pipe gradually moves in the direction of the bending die 52 as the bending die 52 rotates. As a method for causing the chuck 57 to follow the rear end portion 9d of the motor 9 without load, position control of the chuck 57 is performed. Accordingly, the amount of movement y of the rear end portion 9d of the pipe 9 that is moved by being pulled by the bending die 52 (stop position J of the rear end portion 9d when the bending die 52 is stopped, see FIG. 4) is accurately determined in advance. It is necessary to know.

The amount of movement y of the rear end portion 9d of the pipe 9 that is moved by being pulled by the bending die 52 is simply “2πr (q / 360)” (r: bending radius, q: set bending angle). Become. However, since the pipe 9 is pulled by the bending die 52 when bending is performed, “elongation” occurs, and therefore, the movement amount y of the rear end portion 9d is extended from “2πr (q / 360)”. The value is obtained by subtracting w. (The value used for actual control is the stop position J (distance j from the machine origin B) of the rear end portion 9d when the bending die 52 is stopped. This value is “j = sy”. (S is determined from the distance from the machine origin B of the chuck 7 to the feed start position S).

However, since the value of the amount of elongation w generated at the time of bending changes depending on the material, diameter, thickness, bending radius, mold adjustment, etc. of the pipe 9, the amount of elongation w (and hence the amount of movement y) is calculated. It is impossible to determine accurately only by Thus, as described above, when the conventional pipe bending apparatus 51 is used to perform the no-load following bending method, the movement amount y of the rear end portion 9d of the pipe 9 or the stop position J (distance j). In order to grasp the above, a series of preparatory work such as trial bending, measurement of trial bending movement amount, calculation of actual movement amount and the like is required prior to actual bending.

In the present embodiment, the position of the chuck 7 is not controlled, but the torque applied to the ball screw 5 to move the chuck 7 and the feed positioning device 8 is controlled. By setting “t1” (minimum output required to move the chuck 7 and the feed positioning device 8 in the free state not holding the pipe 9 in the direction of the bending die 2), the rear end 9d Therefore, it is not necessary to accurately grasp the extension amount w of the pipe 9, the movement amount y of the rear end portion 9d, and the stop position J (distance j). A series of preparatory work such as measurement of the bending movement amount and calculation of the actual movement amount can be omitted.

However, when a feed forward command is issued to the feed servo motor that supplies driving force to the chuck 7, any position is designated, and this is designated as a feed stop target position K (distance from the machine origin B) of the chuck 7. k). At this time, if the stop target position K is set to a position closer to the feed start position S than the actual stop position J (for example, the position of K ′ shown in FIG. 4), the actual stop is started from that position. In the section U to the position J, the chuck 7 and the feed positioning device 8 cannot follow the rear end portion 9d of the pipe 9 without load. Therefore, the target stop position K must be set closer to the bending die 2 than the actual stop position J.

In the present embodiment, the target stop position K (machine position) according to Equation 1 is set so that the target stop position K (distance k from the machine origin B) is set closer to the bending die 2 than the actual stop position J. The distance k) from the origin B is calculated.

However, in this case, a corresponding “deviation” occurs between the actual stop position J and the target stop position K. That is, when the rotation angle of the bending die 2 reaches a predetermined angle (set bending angle q) and the rotation of the bending die 2 stops, the chuck 7 also stops, and the stop position (first stop position F, The feed forward command pulses of a number (α) proportional to the distance f from the stop target position K to the stop target position K are accumulated in the servo amplifier, and then the output torque of the feed servo motor is increased. When “0” is set and the bending occurring in the pipe 9, the chuck 7, the feed positioning device 8, etc. is released, the chuck 7 slightly moves backward to move the movement amount (from the first stop position F). A number (β) of forward feed command pulses proportional to the distance g to the final stop position G (see FIG. 3 (3)) will accumulate in the servo amplifier.

Therefore, in the present embodiment, as described above, the feed backward command (the number of feed backward command pulses proportional to the distance (f + g) from the final stop position G of the chuck 7 to the feed stop target position K (α + β)) is the control device. These accumulated pulses are canceled out.

In this embodiment, since the machine origin B of the chuck 7 is set in front of the feed stop target position K (in the direction of the bending die 2), information on the feed stop target position K of the chuck 7 (distance k). ) Is obtained by the above equation 1, but when the machine origin B of the chuck 7 is set behind the feed start position S (the direction opposite to the bending die 2), the feed stop target of the chuck 7 is set. Information on the position K (distance k) is obtained by the following equation.

(Formula 2)
k = s + (2πr (q / 360)) c

Next, of the above-described processing methods using the pipe bending apparatus 1 of FIG. 1, a bending method using a pressing force method will be described as a third embodiment of the present invention. The bending method of the pressing force application method of the present embodiment is performed by the same procedure as the bending method of the no-load following method described as the second embodiment, except for two points described below.

In the second embodiment (the no-load following bending method), after the movement of the chuck 7 to the feed start position S is completed, the torque output from the feed servo motor to the ball screw 5 is “t1” (chuck 7 is In the free state where the pipe 9 is not gripped, the minimum output required for moving the feed positioning device 8 and the chuck 7 in the direction of the bending die 2 by operating the ball screw 5. However, in this embodiment, a torque obtained by adding “t2” to “t1” corresponding to the pressing force to be applied to the pipe 9 during bending is output. As a result, the pipe 9 can be bent while applying a pressing force by the torque t2.

Further, after the bending servo motor is stopped, when the torque limit function is used to limit the output torque of the feed servo motor and attenuate it to “0”, in the present embodiment, the torque output is gradually reduced. Is executed. Specifically, when the torque output from the feed servomotor is suddenly changed from “t1 + t2” to “0”, the force is released in the ball screw 5 and the feed positioning device 8 on which the torque is applied. The shock (shock) generated during the transmission is transmitted, and the ball screw 5, the feed positioning device 8, or their components are directly damaged by the impact itself, or the mounting bolt is caused by the vibration of the impact. There is a problem that slack occurs in the feed positioning device 8 and the like.

Therefore, in the present embodiment, a required time until the output is attenuated from “t1 + t2” to “0” is set, for example, this required time is divided into ten, that is, divided into ten stages, and output in the first stage. Is gradually attenuated to 90% and 80% in the second stage, and 0% in the tenth stage, that is, the output is set to "0". By reducing the torque output stepwise in this way, the shock when the force is released can be reduced and the above-mentioned problems can be preferably avoided.

Finally, among the above-described processing methods using the pipe bending device 1 of FIG. 1, a bending resistance-added bending method will be described as a fourth embodiment of the present invention. Except for the points described below, the pulling force addition method bending method of the present embodiment is performed by the same procedure as the pressing force addition method bending method described as the third embodiment.

In the third embodiment (pressing force addition type bending method), the feed stop target position K of the chuck 7 is set in front of the feed start position S (in the direction of the bending die 2), and the position information (machine) The distance k) from the origin B can be obtained by the above formula 1. In this embodiment, as shown in FIG. 5A, the feed stop target position K of the chuck 7 is behind the feed start position S ( The position information (distance k from the machine origin B) is set to the following formula using the feed start position S (distance s from the machine origin B) and a constant v: Is calculated by

(Formula 3)
k = s + v

In the present embodiment, the feed stop target position K of the chuck 7 is set at a position opposite to the advancing direction of the rear end portion 9d of the pipe 9, so that the bending is performed from the control device to the servo amplifier of the bending servo motor. When a forward rotation command is issued, a feed backward command (a number of feed backward command pulses proportional to the distance v from the feed start position S of the chuck 7 to the feed stop target position K) is sent to the servo amplifier of the feed servo motor. Will be emitted.

When a forward bending command and feed backward command are issued from the control device, drive power is supplied from the servo amplifier of the bending servo motor to rotate the bending servo motor, and drive power is supplied from the servo amplifier of the feed servo motor to feed. Torque is output from the servo motor. Then, the bending mold 2 rotates in a predetermined direction as shown in FIG. As the bending mold 2 rotates, the pipe 9 sandwiched between the bending mold 2 and the clamp 3 is pulled in the rotation direction of the bending mold 2, and the bending portion 9 b extends along the outer peripheral surface of the round portion 2 a of the bending mold 2. The pipe 9 is wound and bent.

At this time, the rear end side portion 9c and the rear end portion 9d of the pipe 9 gradually move in the direction of the bending die 2 as the bending die 2 rotates, and the chuck 7 grips the rear end portion 9d. The feed positioning device 8 that holds this also gradually moves in the direction of the bending die 2 together with the rear end portion 9d. However, the feed positioning device 8 and the chuck 7 are provided with a feed servo motor and a ball screw 5. A resistance force that pulls in the direction opposite to that of the bending die 2 is added.

When the rotation angle of the bending die 2 reaches a predetermined angle (set bending angle q), the rotation of the bending die 2 is stopped and the bending process is finished. When the rotation of the bending mold 2 (bending servo motor) stops, the rear end side portion 9c, the rear end portion 9d of the pipe 9, the chuck 7, the feed positioning device 8, and the ball screw 5 also stop. At this time, as shown in FIG. 5B, the chuck 7 is further away from the feed stop target position K than the feed start position S. The number of feed advance command pulses proportional to the distance f from the current position (first stop position F) of the chuck 7 to the feed stop target position K is accumulated in the deviation counter of the servo amplifier of the feed servo motor. It will be. Accordingly, the electric power is still supplied from the servo amplifier to the feed servomotor by these accumulated pulses (α), and torque is output from the feed servomotor. Therefore, also in this embodiment, after the bending servo motor is stopped, the output torque of the feed servo motor is limited by the torque limiting function and attenuated to “0”.

When the output torque of the feed servo motor becomes “0”, the thrust of the ball screw 5 acting on the chuck 7 and the feed positioning device 8 is lost, and the bending occurring in the pipe 9, the chuck 7, the feed positioning device 8 and the like is lost. Since it is opened, the chuck 7 moves slightly forward (in the direction of the bending die 2) (final stop position G, see FIG. 5 (3)). For this reason, feed forward command pulses of a number (β) proportional to the amount of movement (distance g from the first stop position F to the final stop position G) are accumulated in the servo amplifier of the feed servo motor. Will be stacked on top.

Therefore, in the present embodiment, after the output torque of the feed servo motor is set to “0”, a predetermined time is set by the timer count up, and then the accumulated pulses (α + β) of the servo amplifier are read and are composed of the same number of pulses. A feed forward command (a number of feed forward command pulses proportional to the distance (f + g) from the final stop position G of the chuck 7 to the feed stop target position K (α + β)) is issued from the control device and is sent to the servo amplifier of the feed servo motor. It is designed to be entered.

Since the feed back / return command pulse stored in the deviation counter of the servo amplifier and the input feed forward command pulse are opposite to each other in the feed direction of the chuck 7, the feed back / back command pulse stored in the deviation counter is fed forward Subtracted by command pulse. Since the number of pulses coincides with each other, all the accumulated feed / reverse command pulses are subtracted (cancelled), and the accumulated pulses become “0”. As a result, power supply from the servo amplifier to the feed servo motor is stopped, and the feed servo motor is stopped. When the feed servo motor is stopped, the torque limit is released, the clamp 3 and the chuck 7 are opened, the pipe 9 is removed from the pipe bending apparatus 1, or only the clamp 3 is opened, and the next bending process is performed. Therefore, the pipe 9 is moved (positioning to the next feed start position is performed).

Also in this embodiment, as in the third embodiment, after the bending servo motor is stopped, when the torque limit function is used to limit the output torque of the feed servo motor and attenuate it to “0”, the torque output The method of dropping the process step by step is executed. As a result, the shock when the force is released can be reduced, and problems such as damage to the component parts and occurrence of problems due to loosening of the mounting bolts can be suitably avoided.

In this embodiment, since the machine origin B of the chuck 7 is set in front of the feed stop target position K (in the direction of the bending die 2), information on the feed stop target position K of the chuck 7 (distance k). ) Is obtained by the above equation 3, but when the machine origin B of the chuck 7 is set behind the feed start position S (in the direction opposite to the bending die 2), the feed stop target of the chuck 7 is set. Information on the position K (distance k) is obtained by the following equation.

(Formula 4)
k = s−v

1: Pipe bending machine,
2: Bending mold,
2a: Round part,
2b: straight part,
3: Clamp,
4: Pressure type,
5: Ball screw,
5a: shaft,
5b: slider,
7: Chuck,
8: Feed positioning device,
9: Pipe,
9a: tip side portion,
9b: bending portion,
9c: rear end side portion,
9d: rear end,
51: Pipe bending apparatus,
52: bending mold,
53: Clamp,
54: Pressure type,
55: Pressurizing force applying means,
56: Tensile resistance adding means,
57: Chuck,
B: Machine origin,
F: first stop position,
G: Final stop position,
J: Stop position,
K: stop target position,
S: Feed start position,
q: Set bending angle,
r: bending radius,
w: elongation,
y: amount of movement,

Claims

A bending die that performs bending by winding a pipe to be processed around the outer peripheral surface;
A chuck configured to grip a rear end of the pipe;
A feed positioning device configured to hold the chuck and be movable in an axial direction of a rear end portion of a pipe held by the chuck;
A feed servo motor,
A bending servo motor for supplying a rotational driving force to the bending mold;
The feed positioning device and the chuck can be moved in a predetermined direction by being connected to the feed positioning device and converting the output torque of the feed servo motor into the thrust of the slider in the axial direction of the shaft. A configured ball screw; and
And a control device for controlling the output torque of the feed servo motor.
A pipe bending method performed using the pipe bending apparatus according to claim 1,
When the chuck is in a free state, the minimum torque required to move the feed positioning device and chuck in the direction of the bending die is output from the feed servo motor to the ball screw. A no-load follow-up pipe bending method characterized by bending.
After the rotation of the bending mold is stopped, the torque limit function limits the output torque of the feed servo motor to attenuate it to 0, and after a predetermined time, reads the accumulated pulse of the feed servo motor. 3. The no-load following type pipe bending method according to claim 2, wherein a feed backward / reverse command comprising the same number of pulses is issued from the control device to cancel the accumulated pulses.
A pipe bending method performed using the pipe bending apparatus according to claim 1,
When the chuck is in a free state, the pressing force to be applied to the pipe during bending to the minimum torque required to move the feed positioning device and the chuck in the direction of the bending mold A pipe bending method using a pressing force method, wherein bending is performed by adding torque corresponding to the above and outputting torque from the feed servo motor to the ball screw.
After the rotation of the bending mold is stopped, the torque limit function limits the output torque of the feed servo motor to attenuate it to 0, and after a predetermined time, reads the accumulated pulse of the feed servo motor. The pipe bending method according to claim 4, wherein a feed backward / reverse command comprising the same number of pulses is issued from the control device to cancel the accumulated pulses.
6. The method according to claim 5, wherein when the output torque of the feed servo motor is limited and attenuated to 0, the required time is divided into at least two stages and the output torque is gradually reduced. Pipe bending method with pressure applied.
A pipe bending method performed using the pipe bending apparatus according to claim 1,
Set the feed stop target position of the chuck behind the feed start position,
When the controller issues a forward bending command to the bending servomotor, a bending process is performed by issuing a feed backward command to the feed servomotor to perform bending.
After the rotation of the bending mold is stopped, the torque limit function limits the output torque of the feed servo motor to attenuate it to 0, and after a predetermined time, reads the accumulated pulse of the feed servo motor. The pipe bending method according to claim 7, wherein a feed forward command including the same number of pulses is issued from the control device to cancel the accumulated pulses.
9. The method according to claim 8, wherein when the output torque of the feed servo motor is limited and attenuated to 0, the required time is divided into at least two stages and the output torque is reduced stepwise. A pipe bending method using a tensile resistance addition method.