JP3701436B2 - Abutting misalignment correction method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for correcting the misalignment of an abutment, and in particular, to the longitudinal direction of the abutment caused by errors in both the up-and-down direction and the back-and-forth direction such as tilt errors of posts and link mechanisms and accumulated pitch errors of ball screws. The present invention relates to an abutting misalignment correction method and apparatus for correcting misalignment.
[0002]
[Prior art]
In general, in a bending machine, it is well known that a back gauge device is provided at the rear part thereof and a workpiece is positioned prior to bending.
[0003]
An example of the back gauge device in this case is shown in FIG.
[0004]
In FIG. 6, supporters 67 are provided on both sides of the lower table 69, and ball screws 68 pass through the supporters 67, and the ball screws 68 are directly connected to the X-axis motor Mx.
[0005]
A base 65 is screwed onto the ball screw 68, and a stretch 63 is attached to the base 65 via a post 64 so as to be movable in the vertical direction (Z-axis direction). An abutment 62 is mounted on 63 so as to be movable in the longitudinal direction (Y-axis direction).
[0006]
In this back gauge device, as a setup before positioning the workpiece W, first, the rotational speed of the X-axis motor Mx is detected and controlled by the encoder 66, whereby the base 65 screwed into the ball screw 68 is controlled. Determine the position in the front-rear direction (X-axis direction).
[0007]
Accordingly, the position of the abutment 62 attached to the base 65 via the post 64 and the stretch 63 is determined in the front-rear direction (X-axis direction).
[0008]
In this way, after setting up, as shown in FIG. 6, the workpiece W is positioned by contacting the abutment 62, and the distance L between the punch 60 and the center kc of the die composed of the die 61 is set. And bending the workpiece W.
[0009]
[Problems to be solved by the invention]
Conventionally, as described above, the rotational speed of the X-axis motor Mx is detected by the encoder 66 and controlled, so that the base 65 screwed into the ball screw 68 is moved in the front-rear direction (X-axis direction). The position is determined, thereby determining the position of the abutment 62 in the front-rear direction (X-axis direction).
[0010]
Therefore, if there is no error in the ball screw 68 or the like, no positional deviation occurs even if the abutment 62 moves in the front-rear direction, and the distance L between the abutment 62 and the mold center Kc is always constant.
[0011]
However, the ball screw 68 has a pitch error, and when the abutment 62 moves in the front-rear direction, the pitch error is accumulated.
[0012]
Further, since the supporter 67 is cantilevered with respect to the lower table 69 and the abutment 62 moves in the front-rear direction, an error that the supporter 67 bends and the post 64 tilts also occurs.
[0013]
As described above, an error occurs in the vertical direction due to the inclination of the post 64, and an error also occurs in the front-rear direction due to the accumulated pitch error of the ball screw 68. Therefore, an error occurs in both the vertical direction and the front-back direction.
[0014]
As a result, the distance L between the abutment 62 and the mold center Kc is not constant depending on the position of the abutment 62 in the vertical direction (Z-axis direction) and the front-rear direction (X-axis direction).
[0015]
The distance L of the abutment 62 with respect to the mold center Kc has the greatest influence on the flange dimension of the workpiece. As described above, the fact that the distance L is not constant means that a desired flange length cannot be obtained. As a result, the bending accuracy of the workpiece is lowered.
[0016]
The object of the present invention is to correct the position deviation of the abutment in the front-rear direction caused by errors in both the up-down direction and the front-rear direction such as the tilt error of the post and the link mechanism and the accumulated pitch error of the ball screw. An object of the present invention is to improve the bending accuracy of the workpiece by keeping the distance between the tool center and the mold center constant and obtaining a desired flange length.
[0017]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides: (1) an arbitrary error in the front-rear direction of the abutment 5 based on a measured value obtained by measuring an error in a predetermined position in the front-rear direction of the abutment 5 for each predetermined position in the vertical direction Creating an error table 52A in which the error ε of the position X is associated with each predetermined position (lower limit, center, upper limit) in the vertical direction;
(2) above on the basis of the error table 52A created in step (1), the error ε of any position X in the longitudinal direction of the projecting those 5 for any position Z in the vertical direction of the abutment 5, the correction value C _X Creating a plurality of correction value tables 52B for each arbitrary position X in the front-rear direction of the abutment 5 ;
(3) From among the plurality of correction value tables 52B created in the step (2), the correction value table 52B corresponding to the target value L _X in the front-rear direction when the workpiece W is positioned is selected. Steps,
(4) Based on the correction value table 52B selected in step (3) above, the correction value d of the vertical position z1 in the longitudinal target value L _X of the abutment 5 is obtained, and the correction value d is calculated. A method for correcting the misalignment of the abutment, characterized by comprising the step of moving the abutment 5 in the front-rear direction according to the command value added to the target value L _X , and
An error at a predetermined position in the front-rear direction of the abutment 5 is created based on a measurement value measured for each predetermined position in the up-down direction, and an error ε at an arbitrary position X in the front-rear direction of the abutment 5 is determined as a predetermined position in the up-down direction. An error table 52A corresponding to each (lower limit, center, upper limit) ;
Are created based on said error table 52A, abutment 5 of the error ε of any position X in the longitudinal direction of the projecting those 5 for any position Z in the vertical direction, the correction value C _X and the abutment 5 in the longitudinal direction of the A plurality of correction value tables 52B for each arbitrary position X;
Among the plurality of correction value tables 52B, the correction value table 52B corresponding to the target value L _X in the front-rear direction of the abutment 5 when positioning the workpiece W is selected, and based on the selected correction value table 52B . A command value calculation means 51 for calculating a correction value d of the vertical position z1 of the abutment 5 in the longitudinal target value L _X and calculating a command value obtained by adding the correction value d to the target value L _X ; ,
A technical means called an abutting position deviation correction device is provided, which has an abutting control means 53 for moving the abutting 5 in the front-rear direction according to the command value.
[0018]
Therefore, according to the configuration of the present invention, the misalignment of the abutment in the front-rear direction caused by errors in both the vertical direction and the front-rear direction such as the tilt error of the post and the link mechanism and the accumulated pitch error of the ball screw is corrected. Thus, the distance L between the abutment 5 and the mold center kc is kept constant (FIG. 5C), and a desired flange length can be obtained, so that the bending accuracy of the workpiece can be improved. .
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described with reference to the accompanying drawings by embodiments.
FIG. 1 is a diagram showing an embodiment of the present invention.
[0020]
The apparatus shown in FIG. 1 includes an input unit 50, a control unit 51, a storage unit 52, an NC 53, and a processing unit 54.
[0021]
The input unit 50 is, for example, a keyboard, and includes a model of a bending machine used in the present invention, processing conditions such as a flange dimension of the workpiece W (FIG. 5C), and a correction method procedure according to the present invention (FIG. 2). ).
[0022]
The above machining conditions include the conditions for measuring the error ε (FIG. 3A) in the front-rear direction of the abutment 5 before machining the workpiece W (step 101 in FIG. 2).
For example, as measurement conditions, a predetermined position in the front-rear direction of the abutment 5 (for example, 100 mm, 200 mm,..., 500 mm in FIG. 3A) and a lower limit in the vertical direction at each of the predetermined front-rear positions. (For example, 50 mm), the center (for example, 115 mm), and the upper limit (for example, 180 mm).
[0023]
The control unit 51 is, for example, a CPU, calculates a command value for moving the abutment 5 (FIGS. 4 and 5) to a predetermined position based on the input signal S1 from the input unit 50, and the command A control signal S3 corresponding to the value is transmitted to the NC 53 at the next stage.
That is, the control unit 51 controls the back gauge device (FIG. 4) which is the processing unit 54 via the NC 53, and moves the abutment 5 in the front-rear direction and the up-down direction, thereby generating an error ε (FIG. 3A). ) And an error table 52A and a correction value table 52B (FIG. 1) are created, and a command value is calculated by adding the correction value d obtained by searching the corresponding correction value table 52B to the target value.
In addition, the control unit 51 controls the entire apparatus shown in FIG.
[0024]
The storage unit 52 stores an error table 52A and a plurality of correction value tables 52B, and the control unit 51 reads the corresponding correction value table 52B (signal S2) to correct the positional deviation of the abutment 5. The command value for calculating is calculated. In addition, the storage unit 52 temporarily stores the machining conditions and program input from the input unit 50.
[0025]
The NC 53 numerically controls the next processing unit 54 based on the control signal S 3 transmitted from the control unit 51.
[0026]
Specifically, the processing unit 54 is a back gauge device using, for example, a link mechanism B shown in FIG.
[0027]
FIG. 4 shows a case where the back gauge device is applied to a press brake, which is a bending machine, and is a perspective view seen from the rear of the press brake. The depth direction is the X-axis direction, the longitudinal direction is the Y-axis direction, The vertical direction is the Z-axis direction.
[0028]
The press brake of FIG. 4 has a lower table 2 arranged in parallel to the Y-axis direction. An upper table 1 is provided immediately above the lower table 2, and a punch (not shown) mounted on the upper table 1 is provided. The workpiece W (FIG. 5C) is bent by the cooperation of a die (not shown) mounted on the lower table 2.
[0029]
As shown in the figure, a back gauge device having a stretch D is provided at the rear of the press brake. The abutment 5 is movable in the Y-axis direction by a Y-axis motor My (not shown). Is attached (FIG. 5A).
[0030]
The stretch D connects the Z-axis drive mechanisms C at both ends, and the Z-axis drive mechanism C is supported by the X-axis drive mechanism A via the link mechanism B.
[0031]
The link mechanism B is formed by crossing the central portions of the links 3 and 4 and connecting them with pins 34. The link mechanism B is extendable in the Z-axis direction, and its lower end is pivoted to the X-axis drive mechanism A by hinges 9A and 10A. At the same time, its upper end is pivotally attached to the Z-axis drive mechanism C by hinges 15A and 16A.
[0032]
The X-axis drive mechanism A includes an X-axis motor Mx fixed to the lower table 2 via support members 18 and 6, a ball screw 8 coupled to the X-axis motor Mx, and a screw on the ball screw 8. The X-axis drive block 10 moves along the X-axis rail 7, and the X-axis driven block 9 moves along the X-axis rail 7 according to the movement of the X-axis drive block 10.
[0033]
Therefore, by controlling the NC 53 (control signal S4 in FIG. 1), the X-axis motor Mx is driven, and as shown in FIG. 5B, the link mechanism B is moved in the X-axis direction (arrow X1), The entire stretch D is moved in the X-axis direction, whereby the abutment 5 can also be moved in the X-axis direction.
[0034]
The Z-axis drive mechanism C includes a Z-axis motor Mz fixed to the support member 12, a ball screw 14 coupled to the Z-axis motor Mz, and a Z-axis rail 13 screwed into the ball screw 14. And a Z-axis fixed block 16 through which the ball screw 14 passes and is fixed to the support member 12.
[0035]
Therefore, the Z-axis motor Mz is driven under the control of the NC 53 (control signal S4 in FIG. 1), and as shown in FIG. 5C, the Z-axis drive block 15, the Z-axis fixed block 16, and the X-axis driven block 9 and the X-axis drive block 10 are moved closer to and away from each other (arrows X2 and X3), and the link mechanism B is expanded and contracted (arrow Z1) to move the entire stretch D in the Z-axis direction. It can be moved in the axial direction.
[0036]
Further, when the X-axis motor Mx is driven and the abutment 5 is moved in the front-rear direction, depending on both errors such as the inclination error of the link mechanism B and the accumulated pitch error of the ball screw 8, the position depends on the vertical direction (see FIG. 3 (A), FIG. 3 (B)), and the target value in the front-rear direction of the abutment 5 causes an error ε.
[0037]
Hereinafter, the operation of the present invention in such a back gauge device will be described with reference to FIGS.
[0038]
(1) Measurement of the error ε in the front-rear direction of the abutment 5.
First, in step 101 of FIG. 2, the measurement of the error ε in the front-rear direction of the abutment 5 is measured.
[0039]
In this case, the X-axis motor Mx is first driven, the abutment 5 is stopped at a predetermined position in the front-rear direction (FIG. 3A), and in that state, the Z-axis motor Mz is then driven, The error ε in the front-rear direction is measured by stopping 5 at predetermined positions in the vertical direction.
For example, the abutment 5 is stopped at a predetermined position 100 mm (FIG. 3A) in the front-rear direction, and in that state, the Z-axis motor Mz is driven, and the abutment 5 is moved to a lower limit in the vertical direction (for example, 50 mm), The error ε is measured by stopping at the center (for example, 115 mm) and the upper limit (for example, 180 mm).
[0040]
The error ε in this case is an error ε with respect to the target value in the front-rear direction of the abutment 5. For example, if the target value is 100 mm and the measured value is 100.2 mm, the error ε is 0.2 mm. is there.
[0041]
In this manner, as shown in FIG. 3A, the error ε is measured for each of the lower limit, the center, and the upper limit in the vertical direction at a predetermined position 100 mm in the front-rear direction of the abutment 5 (marked with ●). Place).
[0042]
Next, for a predetermined position 200 mm in the front-rear direction of the abutment 5, the error ε is measured for each of the upper, lower, lower, middle, and upper limits (points marked with ●). In this way, the error ε is measured for each of the lower limit, the center, and the upper limit in the vertical direction at predetermined positions 300 mm, 400 mm, and 500 mm in the front-rear direction of the abutment 5 in succession (locations marked with ●). In the present embodiment, the error ε is measured at each of the three locations of the lower limit, the center, and the upper limit in the vertical direction. However, in order to increase the accuracy, it is preferable to increase the number of measurement locations.
[0043]
(2) Creation of error table 52A.
Next, in step 102, an error table 52A is created.
That is, three approximate curves P, Q, and R as shown in the figure are obtained by connecting the measured values (marked with ● in FIG. 3A) obtained in step 101 of the preceding stage with respect to the lower limit, center, and upper limit in the vertical direction. Is obtained. Therefore, by obtaining these three approximate curves P, Q, and R, the error ε with respect to the arbitrary position X in the front-rear direction of the abutment 5 is made to correspond to the lower limit, the center, and the upper limit that are predetermined positions in the vertical direction. The error table 52A is created.
The error table 52A is stored in the storage unit 52 (FIG. 1).
[0044]
(3) Creation of correction value table 52B.
Next, in step 103, a correction value table 52B is created.
[0045]
That is, as described above, the error table 52A created in step 102 is obtained by associating the error ε with respect to the arbitrary position X in the front-rear direction of the abutment 5 for each predetermined position in the vertical direction.
Therefore, the error at the arbitrary position Z in the vertical direction of the abutment 5, that is, the correction value C _X cannot be obtained only by the error table 52 </ b> A.
[0046]
Therefore, with respect to an arbitrary position X in the front-rear direction of the error table 52A, for example, L _X (FIG. 3A), the lower limit (50 mm), the center (115 mm), and the upper limit (180 mm) as predetermined positions in the vertical direction. Errors a, b, and c (locations marked with x in FIG. 3A) as correction values C _X , and predetermined vertical positions 50 mm, 115 mm, and 180 mm at this time as vertical positions Z Plotting is performed (FIG. 3B), and the plotted X marks are connected to obtain an approximate curve T shown in FIG. 3B. Therefore, by obtaining this approximate curve T, the correction value table 52B in which the correction value C _X in the front-rear direction with respect to the arbitrary position Z in the up-down direction of the abutment 5 is stored in the arbitrary position of the abutment 5 in the front-rear direction. It is created for L _X (FIG. 3B).
[0047]
Then, a plurality of correction value tables 52B are created over an arbitrary position X in the front-rear direction of the abutment 5, that is, over the entire length in the front-rear direction, and these are stored in the storage unit 52 (FIG. 1).
[0048]
(4) Operation from selection of the correction value table 52B to movement of the abutment 5
In step 104, the correction value table 52B is selected.
That is, when positioning the workpiece W, it is necessary to obtain, as a correction value, an error with respect to the target value in the front-rear direction of the abutment 5 as a setup before that. Therefore, in step 104, among the plurality of correction value tables 52B created in the previous step 103, the correction value table 52B corresponding to the target value in the front-rear direction of the abutment 5 when positioning the workpiece W. Select.
[0049]
Next, in step 105, a correction value is obtained based on the selected correction value table 52B.
For example, it is assumed that the selected correction value table 52B relates to the target value L _{X in} the front-rear direction of the abutment 5 (FIG. 3B).
[0050]
In this case, since the error ε, that is, the correction value C _X differs depending on the position of the abutment 5 in the vertical direction, a correction value d for the vertical position z1 of the abutment 5 at this time is obtained from the correction value table 52B ( FIG. 3 (B)).
[0051]
The relationship between the correction value table 52B and the back gauge device using the link mechanism B shown in FIG. 4 is as shown in FIG. In order to simplify the drawing, in the back gauge device of FIG. 3C, unlike FIG. 4, the X-axis motor Mx is at the rear of the X-axis drive mechanism A, and the Z-axis motor Mz is at the Z-axis drive mechanism C. It is arranged at the rear part.
For example, in FIG. 3C, the target value in the front-rear direction of the abutment 5 is set to 350 mm, the X-axis motor Mx is driven, and the abutment 5 is first stopped at the target value 350 mm in the front-rear direction. Suppose that the Z-axis motor Mz is driven to raise the abutment 5 while passing predetermined positions 50 mm, 115 mm, and 180 mm in the vertical direction.
[0052]
In this case, for a predetermined position 50 mm in the vertical direction, the error from the target value 350 mm in the front-rear direction is a, which is the correction value a to be obtained (FIG. 3B). For the position 115 mm, the error from the target value 350 mm in the front-rear direction is b, and this is the correction value b to be obtained (FIG. 3B). For a predetermined position 180 mm in the vertical direction, the front-rear direction The error with respect to the target value 350 mm is c, which is the correction value c to be obtained (FIG. 3B).
[0053]
In this way, when the correction value C _X in the front-rear direction when the abutment 5 reaches the arbitrary position z1 in the vertical direction (FIG. 3B) is obtained from the correction value table 52B, d is obtained. (FIG. 3B).
[0054]
Next, at step 106, the correction value d obtained at step 105 is added to the target value in the front-rear direction of the abutment 5 to calculate a command value. Next, in step 107, the control unit 51 transmits the command value to the NC 53, and the NC 53 converts it into a pulse train and inputs it to the X-axis motor Mx, and the X-axis motor Mx sends the link mechanism B to the command system. By moving in the X-axis direction to the value, both abutments 5 are moved in the X-axis direction.
[0055]
In this way, the abutment 5 can reach the target value while correcting the positional deviation in the front-rear direction.
[0056]
(5) Positioning and bending of the workpiece W As described above, when the abutment 5 reaches the target value, the workpiece W is abutted against the abutment 5 in step 108 (FIG. 5C). In step 109, the workpiece W is bent.
[0057]
If all machining is not completed in step 110 (NO), the process returns to step 104 for selecting the corresponding correction value table 52B as the next workpiece W positioning setup, and all machining is completed. (YES), the apparatus is stopped to end the work (END).
[0058]
In the present embodiment, the back gauge apparatus using the link mechanism B (FIG. 4) has been described with respect to the abutting misalignment correction method and apparatus.
[0059]
However, the present invention is not limited to this, and can be applied to the back gauge device using the post 64 (FIG. 6) and any other type of back gauge device. It goes without saying that
[0060]
【The invention's effect】
As described above, according to the present invention, a plurality of correction value tables are created based on the error table, and the correction value table corresponding to the target value in the front-rear direction of the bump is selected. The abutment is moved by a command value obtained by adding this correction value to the target value, and the abutting misalignment correction device is associated with a correction value for an arbitrary position in the vertical direction. A plurality of correction value tables, command value calculating means for calculating a command value obtained by adding the correction value obtained based on the corresponding correction value table to the target value, and moving the abutment in the front-rear direction by the command value Due to the configuration of the abutting control means, the misalignment of the abutting in the front-rear direction caused by errors in both the up-down direction and the front-rear direction such as the tilt error of the post and link mechanism and the accumulated pitch error of the ball screw can be corrected. By holds the distance between the abutting mold center constant as desired flange length is obtained became possible to achieve the technical effect of improving the bending accuracy of the workpiece.
[0061]
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention.
FIG. 2 is a flowchart for explaining the operation of the present invention.
FIG. 3 is a diagram illustrating a relationship between an error table and a correction value table according to the present invention.
FIG. 4 is a configuration diagram of a back gauge device used in the present invention.
FIG. 5 is an explanatory diagram of movement of an abutment according to the present invention.
FIG. 6 is an explanatory diagram of a conventional technique.
[Explanation of symbols]
50 Input unit 51 Control unit 52 Storage unit 53 NC
54 Processing section 52A Error table 52B Correction value table A Y-axis drive mechanism B Link mechanism C Z-axis drive mechanism D Stretch 1 Upper table 2 Lower table 3, 4 Link 5 Abutment 6, 12, 18 Support member 7 X-axis rail 8 , 14 Ball screw 9 X-axis driven block 10 X-axis drive block 13 Z-axis rail 15 Z-axis drive block 16 Z-axis fixed block Mx X-axis motor Mz Z-axis motor P Curve Q showing the change in error at the lower limit of the abutment 5 longitudinal curve L _X abutment 5 shows the change of the correction value by the vertical position of the curve T abutment 5 shows the change of error in the upper limit of the curve R abutment 5 shows the change of error in the middle of the 5 butting any position a, b, any vertical position C _X abutment 5 responsibility of the correction value Z abutment 5 for any position z1 vertical in the longitudinal direction of the correction value d abutment 5 c abutment 5 Correction value for the vertical position Z

Claims (3)

(1) Based on the measured value of the error in the predetermined position in the longitudinal direction of the abutment for each predetermined position in the vertical direction, the error in the arbitrary position in the longitudinal direction of the abutment is handled for each predetermined position in the vertical direction Creating a generated error table;
(2) above on the basis of the error table generated in step (1), the error of an arbitrary position in the longitudinal direction of the projecting those for any position in the vertical direction of the abutment, the correction value table as the correction value, the Creating a plurality for each arbitrary position in the front-rear direction of the abutment ;
(3) a step of selecting a correction value table corresponding to a target value in the front-rear direction of the abutment when positioning the workpiece from the plurality of correction value tables created in the step (2);
(4) Based on the correction value table selected in step (3) above, a command value obtained by calculating a correction value for the vertical position of the target value in the front-rear direction of the bump and adding the correction value to the target value A method for correcting the misalignment of the abutment comprising the step of moving the abutment in the front-rear direction. The error at the predetermined position in the front-rear direction of the abutment is created based on the measured value measured for each predetermined position in the up-down direction, and the error at the arbitrary position in the front-rear direction of the abutment is made to correspond to the predetermined position in the up-down direction. Error table ,
A plurality of correction values for each arbitrary position in the front-rear direction of the abutment, which is created based on the error table, and an error of the arbitrary position in the front-rear direction of the abutment relative to the arbitrary position in the up-down direction of the abutment is a correction value Table,
With selecting the correction value table corresponding to the target value of the longitudinal abutment when positioning the workpiece among of the plurality of correction value tables, the selected correction value Te - based on the table, projecting those Command value calculating means for calculating a correction value of the vertical position of the target value in the front-rear direction, and calculating a command value obtained by adding the correction value to the target value;
An abutting position deviation correcting device, comprising: abutting control means for moving the abutting in the front-rear direction according to the command value.   3. The abutting position according to claim 2, wherein the command value calculating means is constituted by a control unit, the abutting control means is constituted by an NC, and the plurality of correction value tables and error tables are respectively stored in a storage part. Deviation correction device.

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