JP4158639B2 - Hemming method - Google Patents

Description

The present invention relates to a hemming method for bending an edge portion of a workpiece.

As a hemming processing method and a hemming processing apparatus for performing edge bending processing on an edge portion of a work, for example, there is one described in Patent Document 1 below.
JP 2001-286952 A

  By the way, in the hemming processing method and the hemming processing apparatus as described above, when a plurality of bending blades are arranged around the workpiece and edge bending processing is performed on the edge corresponding to each bending blade, Must abut against the corresponding edges simultaneously.

  However, even if each bending blade is set or adjusted in advance so that it contacts the corresponding edge at the same time, the bending edge may be touched by the influence of ambient temperature change, aging of the bending blade, or wear. The contact position may deviate from the position set or adjusted in advance.

  In such a case, the bending blades are not brought into contact with the workpiece edge portion at the same time, and are displaced from each other. Accurate edge bending is not possible.

  In particular, in body panel parts for automobiles, when the edge of the outer panel is edge-bent to overlap the periphery of the inner panel, the outer panel escapes and the relative position shifts from the inner panel. Quality degradation as a part occurs.

  In view of this, when the edge of the workpiece is bent using a plurality of bending blades, even if the position of the bending blade that contacts the workpiece edge deviates from a preset or adjusted position, The purpose is to perform edge bending with high accuracy by preventing the escape.

In order to achieve the above object, the present invention comprises a plurality of bending blades for bending the edges of the workpiece, and provided with servo motors for individually driving the bending blades, and driving all the servo motors. And determining whether the position of each bending blade moved toward the edge of the workpiece is a preset position with respect to the workpiece based on the amount of rotation of the servo motor. When the position of the blade is at a preset position with respect to the workpiece, the contact of each bending blade with the corresponding edge portion is detected by the torque of the servo motor, and the detected torque is predetermined. stop the servomotor exceeds the value, the torque of all the bending servo motor corresponding to the blade exceeds the predetermined value after every stop of the servo motor, the servo There a hemming working method for performing hemming and re driving over data.

According to the present invention, after the torque of the servo motor corresponding to all the bending blades are all greater than a predetermined value for the servo motors are stopped, a hemming and re driving a servo motor for driving each bending blade As a result, when the edge of the workpiece is bent using a plurality of bending blades, even if the position where the bending blade contacts the edge of the workpiece deviates from the preset or adjusted position, Each bending process for the corresponding edge of the bending blade can be started at the same time, so that the workpiece can be prevented from escaping and a highly accurate edge bending process can be performed.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a flowchart showing the operation of the hemming apparatus according to one embodiment of the present invention, and FIG. 2 is a perspective view showing the overall configuration of the hemming apparatus. This hemming processing apparatus is provided with processing units U1, U2, U3, U4 arranged in four directions around the work W, and each processing unit U1, U2, U3, U4 includes an edge (flange) of the work W. ) A pre-bending blade 1 that performs pre-bending on F and a main bending blade 3 that performs main bending after the pre-bending.

  Each processing unit U1, U2, U3, U4 is provided with a servo motor 5 as a driving means individually. Each servo motor 5 sequentially drives both the preliminary bending blade 1 and the main bending blade 3 in each of the processing units U1, U2, U3, U4.

  As a driving method of the pre-bending blade 1 and the main bending blade 3 by the servo motor 5, first, the pre-bending blade 1 is moved close to the workpiece W to perform the pre-bending process on the edge F, and then the pre-bending blade. 1 is moved backward from the workpiece W, and in this state, the main bending blade 3 is moved closer to the edge F of the workpiece W which has been subjected to the pre-bending process to perform the main bending process. The details of this driving method are described in the invention filed by the present applicant as Japanese Patent Application No. 2002-55806, and are therefore omitted here.

  FIG. 3 is a block diagram of a control circuit that controls the operation of the servo motor 5 in the hemming apparatus described above. This control circuit includes a servo motor 5, a bending blade contact detecting means 7 for detecting that the bending blade (the preliminary bending blade 1 or the main bending blade 3) has contacted the corresponding edge F, and the bending blade. When the blade contact detection means 7 detects that the bending blade is in contact with the corresponding edge F, the servo motor 5 that drives the bending blade is stopped and all the bending blades correspond to the edge F. And a control means 9 for re-driving each servo motor 5 to perform hemming when each servo motor 5 stops.

  The bending blade contact detection means 7 detects that the bending blade has contacted the corresponding edge F when the torque (current value) of the servo motor 5 exceeds a predetermined value. .

  Next, based on the flowchart shown in FIG. 1, operation | movement of an above-described hemming processing apparatus is demonstrated. In the following description, the bending blade that detects the contact of the workpiece W with the edge F may be applied to either the preliminary bending blade 1 or the main bending blade 3.

  4 shows the torque (current value) of the servo motor 5, the moving speed of the bending blade, the position of the bending blade (the distance between the bending blade and the edge F with respect to time t in the operation process of the hemming apparatus. Are shown as waveforms.

  First, when hemming is started, the rotation operation of all the servo motors 5 in each of the processing units U1, U2, U3, U4 is started (step 101). Thereafter, it is determined whether or not the position of each bending blade that moves toward the edge F of the workpiece W by driving all the servo motors 5 is in a preset position (flange detection range) with respect to the workpiece W. (Steps 103, 105, 107). The determination of the position of the bending blade is performed by the control means 9 that receives this detection signal after the rotation amount of the servo motor 5 is detected by the bending blade contact detection means 7.

  Here, when the position of each bending blade is within the flange detection range, the torque of each servo motor 5 is detected by the bending blade contact detection means 7, and this torque is a predetermined value (torque T in FIG. The control means 9 determines whether or not (step 109). The servo motor 5 whose torque exceeds a predetermined value is stopped from driving (step 111).

  When the bending blade comes into contact with the edge F, the torque of the servo motor 5 increases. Therefore, when the increased motor torque exceeds a predetermined value, the bending blade contacts the edge F of the workpiece W. It is judged that it has touched.

  The operation of detecting whether or not the bending blade is in contact with the edge F starts at time t1 in FIG.

  Then, the control means 9 determines whether or not all the bending blades corresponding to the servo motors 5 are in contact with the edge F (step 113), and when all the bending blades are in contact with the edge F ( At this time, all servo motors 5 are stopped.) Bending is started at time t2 (step 115).

  The region (1) up to time t1 in FIG. 4 is a state where the bending blade is accelerated when moving closer to the workpiece W, and the region (2) is a constant speed when the bending blade moves closer to the workpiece W. It is a state.

  Subsequent region (3) from time t1 to time t3, which will be described in detail later with reference to FIG. 5, corresponds to the above-described detection operation and subsequent bending operation. The bending is performed by re-driving all the servo motors 5 in a stopped state and moving each bending blade closer to the edge F of the workpiece W.

  The state where the bending blade is closest to the workpiece W and the edge bending process is completed is held in the region (5) from time t3 to t4 (step 117), and then the servo motor 5 is reversed until time t5. The bending blade is returned to the original position by rotating (step 119).

  Here, the region (6) up to time t5 is a state where the bending blade is accelerated when moving away from the workpiece W, and the region (7) is a state where the bending blade is at a constant speed when moving away from the workpiece W. The region (8) is a state where the bending blade decelerates when moving away from the workpiece W.

  FIG. 5 shows in detail the detection operation when the bending blade contacts the edge F of the workpiece W as a torque waveform of the servo motor 5. That is, the servo motor 5 with the bending blade in contact with the workpiece W increases the motor torque at time t1, and then the moving speed of the bending blade in the approaching direction to the workpiece W is reduced in the region (9). In the subsequent area (10) until time t2, the drive of the servo motor 5 is stopped until the remaining last bending blade not yet in contact with the work W comes into contact with the work W. In FIG. 5, T represents the motor torque when the bending blade contacts the edge F of the workpiece W.

  Then, the bending process is started after time t2 when all the bending blades abut against the corresponding edge F. The region (11) after time t2 is a state in which the approaching movement of the bending blade to the workpiece W is accelerated, and the region (12) is brought closer to the state in which the bending blade approaches the workpiece W at a constant speed. Including state.

  FIG. 6 shows the position of the bending blade corresponding to each servo motor 5 when there are three servo motors 5 as the vertical axis and the horizontal axis as time. According to this, the bending blade of the first servo motor contacts the workpiece W at time t11, the bending blade of the second servo motor contacts the workpiece W at time t12, and further the third servo motor at time t13. The bending blade is in contact with the workpiece W.

  When the bending blades of all three servo motors come into contact with the workpiece W at time t2, the servo motors 5 are simultaneously re-driven to move the bending blades closer to the workpiece W and start bending. Then, at time t3, the bending blade is positioned so as to be closest to the edge F of the workpiece W by a bending operation.

  According to the above-described embodiment of the present invention, when all the bending blades abut against the corresponding edge F of the workpiece W, the servo motor 5 that drives each bending blade is re-driven to perform hemming. Is going.

  Thus, when the edge F of the workpiece W is bent using a plurality of bending blades, the position at which the bending blade actually contacts the edge F of the workpiece W is deformed or formed by the temperature of the workpiece W, for example. Even if it is displaced from the preset or adjusted position due to changes in the relative relationship between the rotational position of the motor and the cutting edge position due to aging of the press machine mold or aging of the hemming machine, the bending edge is not attached to the workpiece W. By detecting the contact and temporarily stopping the servo motor 5, one of the bending blades adjacent to each other or the bending blades facing each other comes into contact with the work W first, from one direction received by the work W. Therefore, it is possible to perform edge bending with high accuracy by preventing the workpiece W from escaping.

  In particular, in body panel parts for automobiles, when the edge of the outer panel is edge-bent so as to overlap the periphery of the inner panel, the displacement of the relative position between the outer panel and the inner panel is prevented by preventing the outer panel from escaping. Can be prevented, and the quality of the body panel component is improved.

It is a flowchart which shows operation | movement of the hemming processing apparatus concerning one Embodiment of this invention. It is a perspective view which shows the whole structure of the hemming processing apparatus of FIG. FIG. 2 is a block diagram of a control circuit that controls the operation of a servo motor in the hemming apparatus of FIG. 1. It is a wave form diagram which shows the torque (current value) of the servomotor with respect to time, the moving speed of a bending blade, and the position of a bending blade in the operation | movement process in the hemming processing apparatus of FIG. It is a wave form diagram which shows the detail of the detection operation | movement in FIG. It is a wave form diagram which shows the position of the bending blade corresponding to each servomotor in case there are three servomotors.

Explanation of symbols

W Work F Edge 1 Preliminary bending blade (bending blade)
3 bending blades (bending blade)
5 Servo motor (drive means)
7 Bending blade contact detection means 9 Control means

Claims (1)

  Provided with a plurality of bending blades that bend the edges of the workpiece, and provided with servo motors that individually drive each of the bending blades, approaching the workpiece edge by driving all of the servo motors. It is determined by the amount of rotation of the servo motor whether the position of each moved bending blade is at a preset position with respect to the workpiece, and the position of each bending blade is preset with respect to the workpiece. The contact of each bending blade with the corresponding edge of each of the bending blades is detected by the torque of the servo motor, and the servo motor whose detected torque exceeds a predetermined value is stopped, After the servo motor torque corresponding to the bending blade exceeds the predetermined value and all of the servo motors are stopped, the servo motors are driven again to perform hemming. Hemming working method according to claim.

Images