JP2007000922A - Control method for transfer device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress flexural vibration of a beam of a transfer device without raising the flexural rigidity of the beam and without conducting feedback-control by a vibration sensor or the like. <P>SOLUTION: At a stop position C1 of a clamp stroke curve C for laterally moving the beam, a both-beam-end supporting part is additionally reciprocated in the moving direction before stopping for the time of a half period T/2 of flexural vibration of the beam, while synchronizing the reciprocating movement with the flexural vibration, which is generated by inertial force on stopping intermittent movement of the beam. Thereby, the flexural displacement of the central part of the beam is synchronized with the support position of the both ends of the beam, and flexural vibration of the beam of the transfer device is suppressed without raising the flexural rigidity of the beam and without conducting feedback-control by a vibration sensor or the like. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control method of a transfer device that sequentially conveys a workpiece formed by a forging press to a downstream mold.

  In a transfer device that sequentially conveys a workpiece formed by a forging press to a downstream mold, a pair of left and right end support beams extending in the workpiece conveyance direction provided with a workpiece gripping means are driven by a servo motor. Are moved intermittently in the transport direction, left-right direction, and up-down direction (see, for example, Patent Document 1).

  In such a transfer device, when the intermittent movement of the beam in the left-right direction or the up-down direction is stopped, the elongated beam bends and vibrates at its natural frequency due to inertial force, and the gripping of the workpiece by the gripping means becomes unstable. In some cases, the workpiece may be mishandled or the gripped workpiece may be dropped. When stopping the intermittent movement in the transport direction, since the rigidity of the beam is high in the transport direction, bending vibration does not occur.

  In order to suppress the vibration of the crossbar extending in the direction perpendicular to the workpiece conveying direction, the workpiece is formed on the sheet metal press and transferred to the downstream mold. A vibration sensor that detects the vibration of the crossbar is provided, and the drive of the crossbar by the servo motor is feedback-controlled based on the detection signal (see, for example, Patent Document 2).

JP 2003-290868 A JP 2001-71191 A

  In order to suppress the bending vibration of the beam in the transfer device that conveys the workpiece formed by the forging press described above, it is only necessary to increase the bending rigidity of the beam, but the weight of the beam increases and the cost of the beam itself is reduced. In addition, there is a problem that the cost of the support structure increases.

  In addition, like the crossbar of the transfer device for sheet metal press described in Patent Document 2, it is conceivable to provide a vibration sensor for detecting the vibration of the beam and feedback control the driving of the crossbar by the servo motor. In the feedback control of the vibration phenomenon, there is a possibility that the vibration is amplified due to a control delay due to the acceleration calculation time from the output of the vibration sensor or the response time of the actuator, and there is a problem that it is difficult to reliably suppress the vibration. Further, since a vibration sensor is required, the cost increases, and there is a problem that it takes time to set the vibration sensor every time the beam is replaced. Further, in the case of a hot forging press, since the beam for gripping the workpiece becomes high temperature, the life and reliability of the vibration sensor become a problem.

  Accordingly, an object of the present invention is to suppress the bending vibration of the beam of the transfer device without increasing the bending rigidity of the beam and without performing feedback control using a vibration sensor or the like.

  In order to solve the above-described problems, the present invention provides a pair of left and right end support beams extending in a workpiece conveyance direction provided with a workpiece gripping means formed by a forging press. In the control method of the transfer device that moves the workpiece sequentially to the downstream mold by intermittently moving in the direction, left and right direction and up and down direction, when stopping the intermittent movement of the beam in the left and right direction or up and down direction The beam is oscillated at its natural frequency by inertial force, and is oscillated for half a period of the bending vibration of the beam, and the both-end support portions of the beam are additionally reciprocated in the moving direction before the stop. The method of moving was adopted.

  That is, when stopping the intermittent movement of the beam in the left-right direction or the up-down direction, the beam is tuned to bend and vibrate at its natural frequency due to the inertial force. By additionally reciprocating the support portions at both ends in the direction of movement before stopping, the deflection vibration displacement at the center of the beam and the support positions at both ends of the beam are synchronized, without increasing the bending rigidity of the beam, and The beam bending vibration of the transfer device can be suppressed without performing feedback control using a vibration sensor or the like.

  By controlling the amount of one-way movement of the additional reciprocating movement of the both-end support part of the beam to a value equal to the amplitude of the beam center part due to the bending vibration, the bending vibration of the beam can be more effectively suppressed. .

  According to the control method of the transfer device of the present invention, when the intermittent movement of the beam in the left-right direction or the up-down direction is stopped, the beam is tuned to bend and vibrate at its natural frequency due to inertial force. During the half-cycle time, the beam support at both ends of the beam was additionally reciprocated in the direction of movement before stopping, so the bending vibration displacement at the center of the beam and the support position at both ends of the beam were synchronized, The beam bending vibration of the transfer device can be suppressed without increasing the beam bending rigidity and without performing feedback control using a vibration sensor or the like.

  By controlling the amount of one-way movement of the additional reciprocating movement of the beam both-end support part to a value equal to the amplitude of the beam center part due to the bending vibration, the bending vibration of the beam can be more effectively suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1A, 1B, and 2 show a transfer press for hot forging provided with a transfer device 1 to which a control method according to the present invention is applied. This transfer press is a crank type in which the ram 11 is raised and lowered by rotation of a crankshaft (not shown), and five sets of upper and lower molds Q1 to Q5 are arranged on the ram 11 and the base 12 from the upstream side to the downstream side. A pair of left and right beams 2 of the transfer device 1 that are arranged and extend from the upstream side to the downstream side sequentially convey the workpiece W0 supplied to the supply table 13 to the downstream molds Q1 to Q5, and sequentially turn the workpieces W1 to W1. Forged as W5.

  The pair of beams 2 are provided with six pairs of fingers 3 as gripping means for the workpieces W0 to W5, and the workpiece W5 formed by the most downstream upper and lower molds Q5 is placed on the discharge table 14 as a product. Discharged. Although illustration is omitted, each of the forged workpieces W1 to W5 is lifted from the lower molds Q1 to Q5 by a knockout pin and then held by the fingers 3 of the pair of beams 2.

  As shown in FIG. 3, the transfer device 1 includes servomotors 4a, 4b, and 4c that drive the pair of left and right beams 2 to move in the transport direction, the left and right directions, and the up and down directions, respectively. The forces are converted into reciprocating motions of the nuts 6a, 6b and 6c through the ball screws 5a, 5b and 5c, respectively, and transmitted to the beams 2. The drive of each servo motor 4a, 4b, 4c is controlled by a controller 10 that also controls the drive of the ram 11.

  Both ends of each beam 2 are supported by nuts 6b of ball screws 5b respectively connected to two servo motors 4b that drive in the left-right direction, and each ball screw 5b is supported on an upstream side and a downstream side. 7 is attached. Each support base 7 is provided on an elevating base 8 attached to a nut 6c of a ball screw 5c connected to two servo motors 4c driven in the vertical direction, and the upstream support base 7 is arranged in the transport direction. It is connected to a nut 6a of a ball screw 5a that is connected to one servo motor 4a that drives the servo motor 4a.

  Each of the servo motors 4a, 4b, 4c is driven by the controller 10, and as shown in FIG. 4, during one rotation of the crankshaft that moves the ram 11 up and down, the pair of beams 2 are fed to a feed stroke curve F, Along the clamp stroke curve C and the lift stroke curve L, it moves intermittently by one cycle in the transport direction, left-right direction, and up-down direction.

  As schematically shown in FIG. 5, the pair of beams 2 move from the standby state (P1) opened to the left and right at the middle ascending position in the transport direction so as to move backward and lower and approach the left and right. Then, the workpieces W0 to W5 are gripped by the fingers 3 (P2), and then moved forward in the transport direction (P3), and then the workpieces W0 to W5 gripped away from the left and right directions are released from the fingers 3 ( P4). Thereafter, the pair of beams 2 rise and retract and return to the standby state (P1). By repeating these operations, the workpieces W0 to W5 are sequentially conveyed to the molds Q1 to Q5 and the discharge table 14 on the downstream side one by one. In the stroke curve graph shown in FIG. 4, the positions corresponding to the phases of the strokes of the ram 11 are indicated by these states P1 to P4.

  FIG. 6A shows an enlarged view of the vicinity of the stop position C1 of the clamp stroke curve C that moves each beam 2 shown in FIG. 4 in the left-right direction. The stop position C1 is synchronized with the flexural vibration generated by the inertial force as shown in FIG. 7A when stopping the intermittent movement of each beam 2, and the half cycle (T / During the time 2), an additional reciprocating movement is additionally provided for additionally reciprocating the support portions at both ends of the beam 2 in the moving direction before stopping. The one-way movement amount S of this additional reciprocating movement is controlled to a value equal to the amplitude of the central portion of the beam 2. Therefore, as shown in FIG. 7 (b), the bending vibration is suppressed when the both end support portions of the beam 2 move in the forward path by the movement amount S, and the bending vibration is suppressed as shown in FIG. 7 (c). In this state, the return path is moved to return to the original clamp stroke curve C. Although illustration is omitted, the same additional reciprocating movement is given also at the second stop position C2 of the clamp stroke curve C shown in FIG. 4 and the two stop positions L1 and L2 of the lift stroke curve L.

  FIG. 6B shows a modification of the additional reciprocating movement of the clamp stroke curve C shown in FIG. This modification differs only in that a time lag is provided for the length of one cycle T of the bending vibration of the beam 2 between the stop position C1 and the application start point of the additional reciprocating movement. Therefore, in this modification, the bending vibration of the beam 2 is suppressed from the second vibration.

  In the above-described embodiment, the one-way movement amount S of the additional reciprocation that suppresses the bending vibration of the beam is controlled to a value equal to the amplitude at the center of the beam, but the one-way movement amount S is different from the amplitude value. May be. However, the deflection vibration of the beam can be most effectively suppressed by controlling the one-way movement amount S to the amplitude at the center of the beam.

  As an example, the bending vibration of the beam 2 was measured when an additional reciprocation of the one-way movement amount S was applied at the two stop positions L1 and L2 of the lift stroke curve L shown in FIG. As a comparative example, the bending vibration of the beam 2 when these additional reciprocating movements were not given was also measured. The measurement of the bending vibration of the beam was performed by attaching an accelerometer to the center of the beam.

  FIGS. 8A and 8B show measurement results of the bending vibration of the beam in the example and the comparative example, respectively. In the embodiment shown in FIG. 8A, the vibration acceleration α generated when the beam is lowered and raised is greatly attenuated at each of the stop positions L1 and L2 to which additional reciprocation is given, and in the subsequent stop state. The bending vibration is remarkably suppressed. On the other hand, in the comparative example shown in FIG. 8B, the vibration acceleration α generated when the beam descends and ascends as it is at the stop positions L1 and L2, and gradually attenuates gradually in the subsequent stop state. ing. From these vibration measurement results, the control method of the transfer device according to the present invention, which gives additional reciprocation when the movement of the beam in the horizontal direction or vertical direction is stopped, can effectively suppress the bending vibration of the beam. I understand.

a is a longitudinal front view showing a transfer press to which a control method of a transfer device according to the present invention is applied, and b is a longitudinal front view showing an enlarged arrangement of molds of a. Cross-sectional plan view of FIG. 1 is an external perspective view of the transfer device of FIG. FIG. 3 is a graph showing a beam stroke curve of the transfer device of FIG. The top view which shows typically the state of the beam in each phase of the stroke curve of FIG. a is a graph showing an enlarged main portion of the stroke curve of FIG. 4, b is a graph showing a modification of a FIGS. 6A and 6B are plan views schematically showing beam states when the additional reciprocating movement of FIG. 6A is given. a and b are graphs showing measurement results of bending vibration of the beam in the example and the comparative example, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transfer apparatus 2 Beam 3 Finger 4a, 4b, 4c Servo motor 5a, 5b, 5c Ball screw 6a, 6b, 6c Nut 7 Support stand 8 Lifting stand 10 Controller 11 Ram 12 Base 13 Supply stand 14 Discharge stand Q1-Q5 Mold W0-W5 work

Claims (2)

  A pair of left and right support beams extending in the workpiece conveyance direction provided with a workpiece gripping means formed by a forging press are moved intermittently in the workpiece conveyance direction, left and right direction, and vertical direction by driving a servo motor. Then, in the control method of the transfer device that sequentially conveys the workpiece to the downstream mold, when the intermittent movement of the beam in the horizontal direction or the vertical direction is stopped, the beam is bent at its natural frequency by inertial force. A transfer device characterized in that, in synchronism with the vibration, the both-end support portions of the beam are additionally reciprocated in the movement direction before the stop for a half period of the flexural vibration of the beam. Control method.   2. The method of controlling a transfer device according to claim 1, wherein the one-way movement amount of the additional reciprocating movement of the both-end support part of the beam is controlled to a value equal to the amplitude of the beam center part due to the bending vibration.

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