JP3096000B2 - Straightening method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a straightening method.

[0002]

2. Description of the Related Art Workpieces (eg, transmission shafts) that undergo heat treatment such as quenching and tempering are
In order to remove the strain generated during the heat treatment, the strain is removed by a strain remover. The strain removing machine previously stores the relationship between the strain amount and the indentation amount (= press amount) for each work to be corrected in a memory, and measures and stores the strain amount of the work put into the equipment. The press-in amount is determined from the data and the press is corrected. The above-described relationship between the amount of distortion and the amount of indentation is called a correction curve. When creating this curve (installation on the CPU), the target work is randomly trial-pressed and determined while observing the correction amount at that time. The optimum pushing amount is determined by experience.

[0003]

However, the conventional method of creating a correction curve has the following problems. The distortion area of the data used to create the correction curve (data on the relationship between the amount of distortion and the amount of indentation) is usually narrow (it cannot cover all the variations in the distortion area of the work), and it is corrected when the distortion amount of the work deviates from that area The accuracy of the pushing amount obtained from the curve is low. Since the pushing amount is determined based on experience and intuition, it is difficult to obtain a reliable correction curve. To increase the reliability of the correction curve, a large number of works and an enormous number of man-hours are required. An object of the present invention is that a correction curve used in distortion removal has a wide range of distortion amount and is created (without intuition or scrutiny) based on actual measurement data over the entire range (thus, a reliable curve). ) Is to provide a method for removing distortion.

[0004]

The present invention to achieve the above object is as follows. (1) A method for removing distortion, comprising: a step of creating a correction curve that gives a relationship between a distortion amount and a required indentation amount in distortion removal; and a step of removing distortion of a work according to the correction curve. The process of creating a work press
Until the sensor detects a crack in the work
Or, the condition is satisfied until the stroke monitoring range is exceeded.
The actual stroke at the time of addition is multiplied by the safety factor.
Determining the maximum indentation amount by pressing, dividing the maximum indentation amount into equal parts by a predetermined number, and setting the indentation amount at the division point as a trial indentation amount, and performing a press indentation with the trial indentation amount and correcting at that time. Measuring the amount and creating a correction curve based on the indentation amount from the trial indentation amount and the measured correction amount at that time. 2. The distortion removing method according to claim 1, wherein the step of creating the correction curve further includes a step of converting the correction curve based on the indentation amount into a correction curve based on the distortion amount. (3) The step of creating the correction curve further includes measuring a work distortion amount, performing a press trial using the indentation amount obtained from the distortion amount-based correction curve, and actually measuring the correction distortion amount at that time.
The distortion removal method according to (2), further comprising a correction step of correcting the correction curve based on the distortion amount so as to pass through the points of the trial depression amount and the correction distortion amount.

In the above method (1), the maximum indentation amount is determined, and a correction curve is created for the maximum indentation amount. Therefore, the distortion amount range of the correction curve is wide (it can cover the entire range in which the workpiece can be plastically bent). . In addition, the maximum amount of indentation is equally divided by a predetermined number at all division points, and the amount of distortion is measured by actually performing a press trial, and a correction curve is created based on the distortion amount. It will be.
In addition, the number of workpieces used for the correction curve is one used for determining the maximum indentation amount and at least one used for the press trial, that is, at least two in total. In the method (2), the correction curve based on the indentation amount is converted into a correction curve based on the distortion amount. The function of the straightening machine is to measure the strain amount of the work and determine the pushing amount according to the strain amount. In short, since the reference value is the amount of distortion, a correction curve actually obtained by the above conversion is obtained. In the method (3), the distortion is corrected using the distortion-based correction curve, and the data before the press trial is corrected using the measured data after the press trial.
Therefore, the correction curve based on the distortion amount is improved to have higher reliability as this correction is repeated.

[0006]

FIG. 1 shows the equipment and operation of the straightening method of the present invention. The work 1 is centered and supported by the left and right measurement centers 2 advanced with respect to the work 1 and rotated. The distortion of the work 1 is measured by the differential transformer 4 (the differential transformer is merely an example, and a linear gauge or the like can also be used) while the work 1 is rotated. The rotation of the work 1 is stopped with the bending direction directed toward the press cylinder 6. The left and right centers 2 are retracted from the work 1, and the work 1 is placed on the press work receiving table 3. The work 1 is pressed in while the press stroke is monitored by the differential transformer 4, and the distortion is corrected (distortion removal). The press is raised, the left and right centers 2 are moved forward with respect to the work 1, and the work 1 is centered and supported again. The press result is measured by the differential transformer 4, and the work 1 is rotated again to reduce the amount of distortion. measure. When the amount of distortion falls within the tolerance, the left and right centers 2 are retracted, and the process is terminated. If the amount of distortion exceeds the tolerance, the above operation is performed again. The above steps are performed both in the straightening step and in the step of obtaining the correction curve. The operation of the press is controlled by the press control unit 8, and the press control unit 8 is controlled by the CPU 7. A correction curve, which will be described later, is created and corrected by the CPU 7 and installed.
Activate Reference numeral 5 denotes an AE (acoustic emission) crack detection sensor used for a process for obtaining a correction curve and for monitoring a work crack during a strain removal cycle.

[0007] The straightening method according to the embodiment of the present invention comprises the steps of creating a correction curve that gives the relationship between the amount of strain and the required indentation amount in straightening, and performing the straightening of the workpiece in accordance with the corrected curve. . The process of creating the correction curve is shown in FIG.
Step 101 for determining the maximum indentation amount,
A step 102 in which the determined maximum pressing amount is equally divided by a predetermined number and the pressing amount at the dividing point is determined as a trial pressing amount to determine a trial pressing amount, and a press pressing is performed with each determined trial pressing amount, and each trial pressing is performed. Measuring the correction amount (distortion amount = horizontal axis of the correction curve), and creating a correction curve based on the indentation amount from the trial depression amount and the measured correction amount at that time;
including. The step of creating the correction curve may further include, as shown in FIG. 2, a step 104 of converting the correction curve based on the indentation amount into a correction curve based on the distortion amount. As shown in FIG. 2, in the process of creating a correction curve, the work distortion amount is further measured, and a press trial is performed on the work distortion amount with the indentation amount obtained from the distortion amount-based correction curve. A correction step 105 of actually measuring the distortion amount and correcting the correction curve based on the distortion amount so as to pass through the points of the trial indentation amount and the corrected distortion amount;
106 may be included.

In the step 101 for determining the maximum pushing amount,
As shown in FIG. 3, the work is pressed at a low speed in step 201, and the AE crack detection sensor 5 detects the work 1
Until a crack is detected (step 202) or exceeds the stroke (press machine stroke) monitoring range (step 203), an actual stroke (press machine stroke) at the time when the condition is detected is measured. A value obtained by multiplying the stroke by a safety coefficient (for example, 0.8) is determined as the maximum pushing amount (step 204).
If there are multiple indentation points, the maximum indentation amount of the other press points can be obtained by calculation by inputting the values of the total length of the work, the diameter of the work, the press position, and the position of the cradle, or try the press at each press point. Then, it is obtained by actual measurement in the same manner as described above.

In the step of determining the trial depression amount, as shown in FIG. 4, the maximum depression amount is equally divided by a predetermined number n, and the depression amount at the division point is defined as the trial depression amount. Predetermined number n
Is a positive integer and is an empirically determined value. In the following description, n = 5 as an example. When there are a plurality of press points, the press-in amount is determined for each press point. Specifically, when the maximum pushing amount is 5000 and n = 5, each pushing amount (1), (2), (3), (4),
(5) is 1000, 2000, 3000, 4000,
5000 (= maximum pushing amount).

Next, as shown in FIG. 5 and FIG. 6, press indentations are tried for each indentation amount (1), (2), (3), (4) and (5), and the correction amount (distortion) at that time is tried. Amount = horizontal axis of the correction curve) a, b, c, d, e (the correction amount detected by the differential transformer 4 is twice the amount bent by the press trial)
Is measured, and the trial indentation amounts (1), (2), (3),
(4), (5) and the measured correction amounts a, b, c, d,
A correction curve based on the indentation amount is created from e. Specifically, when the pressing amount (1) is 1000, the corrected amount a is 200, when the pressing amount (2) is 2000, the corrected amount b is 600, and when the pressing amount (3) is 3000, the corrected amount a is corrected. When the pressed amount (4) is 4000, the corrected amount d is 1200, when the pressed amount (5) is 5000, the corrected amount e is 1500, and so on. In creating a correction curve, the correction amount (distortion amount) is set on the horizontal axis, the indentation amount is set on the vertical axis, the measurement points are plotted on a graph, and those points are connected by a straight line to create a correction curve based on the indentation amount. I do.

In FIG. 5, in step 301, the trial depression amount (in the above example, 1000, 2000, 3000, 400
0, 5000). On the way, if the AE crack sensor 5 detects a crack in Step 302, the actual stroke at that time returns to Step 201 in FIG. 3 and a press trial is performed with a new work. If no crack is detected in step 302, the flow advances to step 304 to execute measurement at all measurement points (including the point of maximum indentation). When measurement at all measurement points is completed (step 304), the flow proceeds to step 303. The correction amounts (distortion amounts) a, b, c, d, and e at the respective measurement points are determined. Based on this, the correction curve of FIG. 6 is created. However, the minimum indentation amount is empirically set to 10% (changeable) of the maximum indentation amount (see FIG. 6), and that point is connected to the next point (point where the distortion amount is a).
The correction curve thus created is a correction curve based on the indentation amount (the indentation amount is equally divided). The distortion correction may be performed using this correction curve, or, as described below, the correction curve may be converted and corrected, and the distortion correction may be performed according to the correction curve.

Next, the correction curve based on the indentation amount (correction curve in FIG. 6) is converted into a correction curve based on the distortion amount (correction curve in FIG. 7). In this process, the section of the distortion amount (correction amount) 0 to e in the correction curve based on the indentation amount (the correction curve in FIG. 6) is divided into N equal parts (N is a maximum of about 10 empirically), and the point is set to 1 ,
2,... N. The correction amounts 1 to N are correction amounts n = n × e / N, where 1 pitch width = corrected amount e / N. Specifically, the correction amount (1): 150, the correction amount (2): 300, the correction amount (3): 450, the correction amount (4): 600, the correction amount (5): 750, and the correction amount (6). : 900, correction amount (7): 1050, correction amount (8): 1200, correction amount (9): 1350, correction amount (10): 1500.

As shown in FIG. 8, the method of calculating the indentation amount with respect to each correction amount (n) is as follows: the indentation at the correction amount n (n = 1, 2,... N) on the correction curve based on the indentation amount. Assuming that the amount is the indentation amount n, the indentation amount n = A × the correction amount n + B, where A: the slope of the indentation amount n on the indentation amount-based correction curve B: the tangent of the indentation amount n in the indentation amount-based correction curve In the above example, the indentation amounts 1 to 10 are as follows: 1: ((1000-500) / 200) × 150 + 500 = 875 2: ((2000-1000) / (600-200) )) × (300-200) + 1000 = 1250 3: ((2000-1000) / ( 600 -200)) × (450-200) + 1000 = 1625 4: ((2000-1000) / ( 600 -200)) × (600-200) + 1000 = 2000 5: ((3000-2000) / (800-600)) × (750-600) + 2000 = 2750 6: ((4000-3000) / (1200-800)) × ( 900-800) + 3000 = 3250 7: ((4000-3000) / (1200-800)) × (1050-800) + 3000 = 3625 8: ((4000-3000) / (1200-800)) × (1200-800) 800) + 3000 = 4000 9: ((5000-4000) / ( 1500-1200)) x (1350-1200) + 4000 = 4500 10: ((5000-4000) / (1500-1200)) x (1500-1200) + 4000 = 5000

Next, correction of the correction curve based on the distortion amount (FIG. 2)
Steps 105 and 106) are performed. In this step, a pressing operation is performed using a correction curve based on the amount of strain, and measurement is performed each time pressing is performed, and correction calculation is performed. The selection of rotation measurement / stationary measurement is determined and set in advance for an object based on experience. Usually, stationary measurement is performed. In the distortion amount calculation method, in the case of static measurement, the amount of bending by press × 2 is a corrected amount. The correction is performed under the following conditions. The press-in amount is obtained from the correction curve in order from the correction amount 1, and a press trial is performed. As shown in FIG. 9, a press trial is performed with the pushing amount b obtained from the work deflection amount (distortion amount) a as a correction curve, and the correction curve is corrected from the correction amount c for the actual stroke. That is, in the left diagram of FIG. 9, it is assumed that the indentation amount of the distortion amount a is determined by the correction curve (determined as b), and when the press-in of b is tried, the distortion is corrected by c. The correction curve based on the amount of distortion is corrected so that the new correction curve passes through the point (actual measurement point) of the indentation amount b with respect to the correction amount c (FIG. 9).
To the right), while maintaining the overall slope ratio.

A specific example of the correction calculation method will be described below. The correction amount x and the correction amount x + 1 closest to c are selected. The distortion amount is c
Is determined from the correction curve, and is defined as p. Assuming that the press stroke in which the press was attempted is q, the correction amount s of the press-in amount is s = q-p. The curve is moved up and down by adding s to the pushing amount x and the pushing amount x + 1. The following calculation is performed to correct the pressing amount n in the part where n <x. Pressing amount n = pressing amount n + (s × (correction amount n / correction amount x)) The following calculation is performed to correct the pressing amount n in the part where n> x. Depression amount n = depression amount n + (s × ((correction amount N−correction amount n) / (correction amount N−correction amount x + 1))) where correction amount N: correction amount at the maximum depression amount

A specific example is as follows. It is assumed that the amount of strain before pressing = 650 and the amount of strain after pressing = 100. Prestroke = ((2750-2000) / (750-600)) x (650-600) +2000 = 2250 Position to be corrected (correction amount) = 650-100 = 550 (Push amount 3,
4) Prestroke when correction amount is 550 = ((2000
-1625) / (600-450)) x (550-450) +1625 = 1875 Correction amount = 2250-1875 = 375 Push amount 3 = 1625 + 375 = 2000 (vertical parallel movement) Push amount 4 = 2000 + 375 = 2375 (vertical parallel movement) For other pressing amounts, the correction amount is added according to the distance ratio from both ends of the position to be corrected. Pushing amount 2 = 1250 + (375 × (300/450 )) = 1500 Pushing amount 1 = 875 + (375 × (150/450 )) = 1000 Pushing amount 5 = 2750 + (375 × ((1500-750) / (1500- 600))) = 3062 Push amount 6 = 3250 + (375 × ((1500-900) / (1500-600))) = 3500 Push amount 7 = 3625 + (375 × ((1500-1050) / (1500-600) )) = 3812 Push amount 8 = 4000 + (375 × ((1500-1200) / (1500-600))) = 4125 Push amount 9 = 4500 + (375 × ((1500-1350) / (1500-600))) = 4562

The maximum pushing amount is fixed. The minimum pushing amount is fixed by using the value determined by the ratio to the maximum pushing amount according to the setting. Correction is performed for each measurement point, and the process is repeated a set number of times (number of workpieces). The number of repetitions is set to a minimum value to limit the minimum number, so that even if a press trial exceeding the set number is performed, it can be processed.

The operation of the method according to the embodiment of the present invention will be described. The maximum pushing amount is determined as the cracking pushing amount or the value obtained by multiplying the stroke monitoring range of the press machine by the safety factor, and a correction curve is created for it.Therefore, the distortion amount range of the correction curve is wide, Substantially covers the entire distortion range. Therefore, the distortion range of the work does not deviate from the distortion amount range of the correction curve, and there is no decrease in accuracy due to deviating from the distortion amount range. In addition, since the amount of distortion is actually measured by performing a press trial at all division points obtained by equally dividing the maximum indentation amount by a predetermined number and a correction curve is created based on the distortion amount, the correction curve does not depend on intuition or experience. Therefore, although there is a variation due to the data, no matter who does it, a correction curve with the same result is obtained, and the method is reproducible. In addition, the number of workpieces used for the correction curve is one used for determining the maximum indentation amount and at least one used for the press trial, that is, at least two in total.

When the correction curve based on the indentation amount is converted into a correction curve based on the distortion amount, the following operation is further obtained. The function of the straightening machine is to measure the strain amount of the work and determine the pushing amount according to the strain amount. In short, since the reference value is the amount of distortion, the above-described conversion can approximate a correction curve (an actually corrected correction curve) from which the amount of indentation can be obtained with high reliability from the amount of distortion. When the correction curve is corrected, the following operation is further performed. Since the distortion is corrected using the distortion amount-based correction curve, and the data before the press trial is corrected using the actually measured data after the press trial, the reliability is improved. Moreover, the number of workpieces is at most 10 (not a fixed value)
Therefore, the number of steps is extremely small and the number of steps is small as compared with the related art.

[0020]

According to the distortion removing method of the present invention, the maximum indentation amount is determined, and the maximum indentation amount is equally divided by a predetermined number to determine the indentation amount. Since the correction curve is created on the basis of the actually measured data, the distortion amount range of the correction curve is wide, and it is possible to perform accurate distortion removal without depending on intuition. Further, it is possible to create a correction curve with a small number of works. According to the distortion removing method of the second aspect, since the correction curve is converted into the correction curve based on the distortion amount, the correction curve conforms to the actual distortion removal, and the correction curve can be easily corrected. According to the distortion removing method of the third aspect, the correction curve based on the distortion amount is corrected by the actually measured value, so that the correction curve has high accuracy, and the reliability of the distortion removal is improved. In addition, this correction can be performed with a small number of works.

[Brief description of the drawings]

FIG. 1 is a front view of an apparatus for performing a method according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a process of creating a correction curve in the method of the embodiment of the present invention.

FIG. 3 is a flowchart illustrating a maximum indentation amount determining step in the correction curve creating step in the method according to the embodiment of the present invention.

FIG. 4 is a graph showing a relationship between a maximum indentation amount and a trial indentation amount obtained by dividing the maximum indentation amount in a process of creating a correction curve in the method according to the embodiment of the present invention.

FIG. 5 is a flowchart showing a step of determining a correction amount for a press-in amount in a correction curve creation step in the method of the embodiment of the present invention.

FIG. 6 is a graph showing a correction curve based on the indentation amount created by the method of the embodiment of the present invention.

FIG. 7 is a graph showing the conversion from the correction curve based on the indentation amount to the correction curve based on the distortion amount in the method of the embodiment of the present invention.

FIG. 8 is a graph showing parameters for calculating the amount of depression for the correction amounts 1 to n on the correction curve based on the amount of depression in the method of the embodiment of the present invention.

FIG. 9 is a graph showing a process of correcting a correction curve based on a distortion amount in the method according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Work 2 Measurement center 3 Work rest for press 4 Differential transformer 5 AE crack detection sensor 6 Cylinder for press 7 CPU 8 Press control unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-199026 (JP, A) JP-B-52-34428 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21D 3/10

Claims (3)

(57) [Claims] 1. A distortion removing method comprising: a step of creating a correction curve that gives a relationship between a distortion amount and a required indentation amount in distortion removal; and a step of removing distortion of a work according to the correction curve. the step of creating a correction curve, the work
Pressing the sensor to detect cracks in the work
Up to or beyond the stroke monitoring range.
The safety factor was applied to the actual stroke when the condition was satisfied
A step of determining the maximum indentation amount as a value, a step of equally dividing the maximum indentation amount by a predetermined number, and setting the indentation amount at the division point to a trial indentation amount, and performing a press indentation with the trial indentation amount, and Measuring the amount of correction and creating a correction curve based on the amount of indentation from the amount of trial indentation and the amount of correction measured at that time. 2. The distortion removing method according to claim 1, wherein the step of creating the correction curve further includes a step of converting the correction curve based on the indentation amount into a correction curve based on the distortion amount. 3. The step of creating the correction curve further includes measuring a work distortion amount, performing a press trial with a pressing amount obtained from the distortion amount-based correction curve, and actually measuring a distortion correction amount at that time. 3. The method according to claim 2, further comprising the step of correcting the correction curve based on the distortion amount so as to pass through the points of the trial depression amount and the distortion correction amount.
The straightening method described.