Method and device for correcting distortion of long workpiece

Abstract

To provide a novel method for correcting distortion of a long workpiece, which can correct the distortion of the long workpiece.SOLUTION: The method for correcting the distortion of a long workpiece includes the steps of: acquiring distortion amounts of the workpiece at a plurality of places in a longitudinal direction; calculating, through simulation, an elastic deformation amount of a straight reference bar when the reference bar is pressed to be elastically deformed at a given pressing position, a given reception position, and given load associated information; calculating a distortion residual amount when it is assumed that the workpiece is elastically deformed only by the elastic deformation amount on the basis of the distortion amount and the elastic deformation amount; and acquiring a pressing position and a reception position when the distortion residual amount is within a permissible range.SELECTED DRAWING: Figure 15

Description

[Technical field]

[0001] The present disclosure relates to a method and device for straightening a distortion of a long workpiece. [Background technology]

[0002] The following Patent Document 1 discloses a method for determining the position and amount of correction for bending. That is, first, the runout of a bar (workpiece) is measured at multiple positions in the longitudinal direction of the workpiece. Then, if the runout is larger than the correction standard, the amount of correction that minimizes the runout is determined at the position and phase where the runout is maximum.

[0003] Next, the predicted runout is compared with the runout target to determine whether the predicted runout is smaller than the runout target. If the predicted runout is smaller than the runout target, correction is performed. If the predicted runout is larger than the runout target, a correction amount is obtained that makes the partial bending zero at the position and phase where the partial bending is maximum. Correction is performed according to the correction amount.

[0004] In the determination method of Patent Document 1, the process of determining the correction amount that minimizes the shake at the position and phase where the shake is maximum is complicated. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2001-105028 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a method and device for correcting distortion of a long workpiece, which makes it possible to correct distortion of a long workpiece in a novel manner. [Means for solving the problem]

[0007] One embodiment of the present disclosure provides a method for correcting distortion of a long workpiece, the method including the steps of: acquiring distortion amounts at multiple locations in the longitudinal direction of the workpiece; calculating by simulation an amount of elastic deformation of a straight reference bar when the reference bar is elastically deformed by pressing at a given press position, a given receiving position, and given load-related information; calculating a remaining amount of distortion when it is assumed that the workpiece is elastically deformed by the elastic deformation amount based on the amount of distortion and the amount of elastic deformation; and acquiring the press position and the receiving position when the remaining amount of distortion is within an acceptable range.

[0008] This method provides a method for correcting distortion of a long workpiece, which makes it possible to correct distortion of the long workpiece in a novel manner.

[0009] One embodiment of the present disclosure provides a distortion correction device for a long workpiece that corrects distortion by pressing the long workpiece, the device comprising: a plurality of sensors that measure the amount of distortion of the workpiece at multiple locations in the longitudinal direction of the workpiece; a pressing member that is movable in the longitudinal direction of the workpiece and can press the workpiece at any position in the longitudinal direction of the workpiece; and a receiving member that is movable in the longitudinal direction of the workpiece and receives the workpiece when it is pressed, wherein the pressing position of the pressing member and the receiving position of the receiving member are set based on the press position and the receiving position obtained by the distortion correction method for a long workpiece, respectively.

[0010] With this configuration, an apparatus for correcting distortion of a long workpiece can be obtained, which is capable of correcting distortion of a long workpiece in a novel manner. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing an example of a long workpiece that is a target of a method for correcting distortion of a long workpiece according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3]FIG. 3 is a flowchart for explaining an outline of the first distortion correction processing. [Figure 4] FIG. 4 is a schematic diagram showing a schematic configuration of a distortion correction device. [Diagram 5] Figure 5 is a graph showing an example of position information detected by the fifth to seventh linear sensors relative to phase information detected by the rotational angle sensor, where Figure 5A is a graph for the fifth linear sensor Q5, Figure 5B is a graph for the sixth linear sensor Q6, and Figure 5C is a graph for the seventh linear sensor Q7. [Figure 6] Figure 6 is a graph to explain setting the phase θa at which the position information is maximum as 0° of the work phase in the linear sensor with the maximum PP value among multiple linear sensors, where Figure 6A is a graph for the fifth linear sensor Q5, Figure 6B is a graph for the sixth linear sensor Q6, and Figure 6C is a graph for the seventh linear sensor Q7. [Figure 7] Figure 7 is a graph to explain how the position of the point at which the position information is maximum in a graph showing position information versus phase information is plotted on polar coordinates using 1 / 2 the PP value and the work phase, where Figure 7A is a graph for the fifth linear sensor Q5, Figure 7B is a graph for the sixth linear sensor Q6, and Figure 7C is a graph for the seventh linear sensor Q7. [Figure 8] FIG. 8 is a graph to explain how the vertical axis component of a polar coordinate vector is calculated as the vertical distortion amount, and the horizontal axis component is calculated as the horizontal distortion amount, where FIG. 8A is a graph for the fifth linear sensor Q5, FIG. 8B is a graph for the sixth linear sensor Q6, and FIG. 8C is a graph for the seventh linear sensor Q7. [Figure 9] FIG. 9A is a line graph showing the amount of vertical strain versus the longitudinal position of the workpiece obtained from the amount of vertical strain for the fifth to seventh linear sensors Q5 to Q7, and FIG. 9B is a line graph showing the amount of lateral strain versus the longitudinal position of the workpiece obtained from the amount of lateral strain for the fifth to seventh linear sensors Q5 to Q7. [Figure 10]Figures 10A to 10D are schematic diagrams showing a state in which the rotation angle of the workpiece is such that the flat surface of the workpiece is parallel or perpendicular to the floor surface, and Figure 10E is a schematic diagram showing a state in which the rotation angle of the workpiece is such that the flat surface of the workpiece is oblique to the floor surface. [Figure 11] FIG. 11 is a schematic diagram for explaining how the rotation angle of the workpiece, in which the flat surface of the workpiece faces upward, is set to 0° in the workpiece phase. [Figure 12] Figure 12 is a graph showing an example of position information detected by the first to third linear sensors relative to phase information detected by the rotational angle sensor, where Figure 12A is a graph for the first linear sensor Q1, Figure 12B is a graph for the second linear sensor Q2, and Figure 12C is a graph for the third linear sensor Q3. [Figure 13] Figure 13 is a graph to explain setting the central phase θb ​​of the phase section treated as a missing value as 0° of the work phase, where Figure 13A is a graph for the first linear sensor Q1, Figure 13B is a graph for the second linear sensor Q2, and Figure 13C is a graph for the third linear sensor Q3. [Figure 14] FIG. 14 is a flowchart showing a detailed procedure of the longitudinal distortion correcting process in step S3 of FIG. [Figure 15] FIG. 15 is a flowchart showing a detailed procedure of the pressing condition searching process in step S14 of FIG. [Figure 16] FIG. 16 is a line graph showing an example of the amount of vertical strain for each linear sensor acquired in step S21 of FIG. [Figure 17] FIG. 17 is a schematic diagram showing a deflection model of a beam supported at both ends. [Figure 18] Curve K1 in Figure 18 is a graph showing the amount of post-press deformation of the reference bar based on the workpiece support, and curve K2 in Figure 18 is a graph showing the amount of post-press deformation of the reference bar based on both ends after conversion when the amount of post-press deformation of the reference bar based on the workpiece support shown by curve K1 is converted into the amount of post-press deformation based on both ends of the reference bar. [Figure 19]FIG. 19 is a graph for explaining a method for calculating the residual distortion amount after pressing a workpiece. [Figure 20] FIG. 20 is a graph showing an example of the relationship between the strain relief deformation amount DA and the press stroke amount PS. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] [Description of the embodiments of the present disclosure] One embodiment of the present disclosure provides a method for correcting distortion of a long workpiece, the method including the steps of: acquiring distortion amounts at multiple locations in the longitudinal direction of the workpiece; calculating by simulation an amount of elastic deformation of a straight reference bar when the reference bar is elastically deformed by pressing at a given press position, a given receiving position, and given load-related information; calculating a remaining amount of distortion when it is assumed that the workpiece is elastically deformed by the elastic deformation amount based on the amount of distortion and the amount of elastic deformation; and acquiring the press position and the receiving position when the remaining amount of distortion is within an acceptable range.

[0013] This method provides a method for correcting distortion of a long workpiece, which makes it possible to correct distortion of the long workpiece in a novel manner.

[0014] In one embodiment of the present disclosure, the method includes a step of correcting distortion of the workpiece by supporting the workpiece at the receiving position when the amount of remaining distortion is within an acceptable range, and pressing the workpiece at the pressing position when the amount of remaining distortion is within an acceptable range.

[0015] In one embodiment of the present disclosure, the method includes a step of acquiring the load-related information when the remaining distortion amount is within an acceptable range, a step of calculating a distortion relief deformation amount required to remove distortion from the workpiece from the load-related information, and a step of calculating a press stroke amount for obtaining the distortion relief deformation amount by plastic deformation.

[0016] In one embodiment of the present disclosure, the method includes the step of correcting distortion of the workpiece by supporting the workpiece at the receiving position when the remaining amount of distortion is within an acceptable range, and pressing the workpiece by the press stroke amount at the pressing position when the remaining amount of distortion is within an acceptable range.

[0017] In one embodiment of the present disclosure, the step of calculating the elastic deformation amount of the reference bar and the step of calculating the residual strain are repeatedly performed until the residual strain amount falls within an allowable range.

[0018] In one embodiment of the present disclosure, the strain amounts at multiple locations in the longitudinal direction of the workpiece are strain amounts based on both ends, where the strain amounts at both ends of the workpiece are zero, and in the process of calculating the elastic deformation amount of the reference bar, a given press position, a given receiving position, and given load-related information are used to calculate an elastic deformation amount based on a receiving position standard, where the elastic deformation amount at the receiving position of the reference bar is zero, and from the elastic deformation amount based on the receiving position standard, an elastic deformation amount based on both ends, where the elastic deformation amount at both ends of the reference bar is zero, is calculated, and the elastic deformation amount based on both ends is calculated as the elastic deformation amount of the reference bar.

[0019] One embodiment of the present disclosure provides a distortion correction device for a long workpiece that corrects distortion by pressing the long workpiece, the device comprising: a plurality of sensors that measure the amount of distortion of the workpiece at multiple locations in the longitudinal direction of the workpiece; a pressing member that is movable in the longitudinal direction of the workpiece and can press the workpiece at any position in the longitudinal direction of the workpiece; and a receiving member that is movable in the longitudinal direction of the workpiece and receives the workpiece when it is pressed, wherein the pressing position of the pressing member and the receiving position of the receiving member are set based on the press position and the receiving position obtained by the distortion correction method for a long workpiece, respectively.

[0020] With this configuration, an apparatus for correcting distortion of a long workpiece can be obtained, which is capable of correcting distortion of a long workpiece in a novel manner.

[0021] Detailed Description of the Embodiments of the Present Disclosure Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0022] [1] Specific examples of long workpieces Fig. 1 is a schematic diagram showing an example of a long workpiece to be subjected to a method for straightening a distortion of a long workpiece according to an embodiment of the present disclosure, Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1.

[0023] In this embodiment, the long workpiece (hereinafter referred to as "workpiece 1") is a rack shaft. The workpiece 1 has a first end 1a and a second end 1b. The workpiece 1 has a toothed portion 2 on which rack teeth 2a are formed, and a threaded portion 3 on which a male thread 3a is formed. The toothed portion 2 is formed on the first end 1a side of the workpiece 1, at a distance from the first end 1a in the longitudinal direction of the workpiece 1. The threaded portion 3 is formed on the second end 1b side of the workpiece 1 relative to the toothed portion 2, at a distance from the toothed portion 2 in the longitudinal direction of the workpiece 1.

[0024] When the workpiece 1 is mounted on a vehicle as a rack shaft, the rack teeth 2a mesh with a pinion shaft that rotates in response to the rotation of a steering wheel, for example. The male screw 3a constitutes a part of a ball screw mechanism that is driven by an electric motor for assisting, for example.

[0025] The cross section of the workpiece 1 is substantially circular except for the teeth portion 2. The cross section of the teeth portion 2 is substantially D-shaped as shown in FIG. 2. That is, in the teeth portion 2, rack teeth 2a are formed on a flat surface 4. A back surface 4a of the flat surface 4 forms a part of a cylindrical surface centered on the central axis 5 of the workpiece 1.

[0026] After hardening (heat treatment) is performed on the tooth portion 2 side, a first distortion straightening process is performed. After the first distortion straightening process, hardening (heat treatment) is performed on the thread portion 3 side. After hardening is performed on the thread portion 3 side, a second distortion straightening process is performed.

[0027] The first distortion correction process and the second distortion correction process may differ in the number and positions of the measurement points of the distortion amount, but the correction process method is the same, so the first distortion correction process will be mainly described below. Note that the number and positions of the measurement points of the distortion amount may be the same or different between the first distortion correction process and the second distortion correction process.

[0028] [2] Overview of the first distortion correction process FIG. 3 is a flowchart for explaining an outline of the first distortion correction processing.

[0029] First, the amount of strain (deflection) for each phase is measured at multiple strain measurement positions in the longitudinal direction of the workpiece 1 (step S1). The amount of strain is the maximum amount of change in distance from the central axis 5a to the surface of the workpiece 1 when the workpiece 1 is rotated around the central axis 5a.

[0030] Next, the amount of longitudinal strain and the amount of lateral strain at each strain measurement position are calculated based on the amount of strain for each phase at each strain measurement position measured in step S1 (step S2).

[0031] Next, a longitudinal distortion correction process is performed to correct the longitudinal distortion (step S3).

[0032] Finally, a horizontal / longitudinal distortion correction process is performed to correct the horizontal distortion (step S4).

[0033] [3] Detailed explanation of steps S1 and S2 [3-1] Schematic configuration of the distortion correction device FIG. 4 is a schematic diagram showing a schematic configuration of a distortion correction device.

[0034] The distortion correction device 10 includes a support unit (not shown) for supporting the workpiece 1 so as to be rotatable about its central axis 5. The distortion correction device 10 also includes a workpiece rotation drive device (not shown) for rotating the workpiece 1 about its central axis 5.

[0035] The distortion correction device 10 also includes a plurality of linear sensors (position sensors) for measuring the amount of distortion of the workpiece 1 at a plurality of distortion measurement positions.

[0036] In this embodiment, in the first distortion correction process, (Q 1 )~(Q 5 Five linear sensors (Q 1 )~(Q 5 In this embodiment, in the second distortion correction process, Q 1 ~Q 8 Eight linear sensors Q 1 ~Q 8 is used.

[0037] Linear sensor (Q 1 ), (Q 2 ), (Q 3 ) and (Q 4 ) are linear sensor Q 1 , Q 2 , Q 3 and Q 4 Corresponding to the linear sensor (Q 5 ) is a linear sensor Q 7 The linear sensor Q used in the second distortion correction process corresponds to 1 ~Q 8 Among them, Linear Sensor Q 1 ~Q 4 and Q 7 The positions of the arrangement of the first distortion correction process (Q 1 )~(Q 5 ) may be located at the same position as or at a different position.

[0038] In this embodiment, the linear sensor Q 1 ~Q 3 ((Q 1 )~(Q 3 )) are arranged at a distance from the longitudinal direction of the toothed portion 2 of the workpiece 1. 4 ~Q 8 ((Q 4 ) and (Q 5)) is longitudinally spaced apart from the area of ​​the workpiece 1 between the toothing 2 and the second end 1b.

[0039] Each linear sensor Q 1 ~Q 8 ((Q 1 )~(Q 5 Each linear sensor Q may be of the contact type or of the non-contact type. 1 ~Q 8 ((Q 1 )~(Q 5 )) measures the distance from the reference position of the linear sensor to the surface of the workpiece 1 while the workpiece 1 is being rotated. In other words, each linear sensor Q 1 ~Q 8 ((Q 1 )~(Q 5 )) detects the position of the surface of the workpiece 1 while the workpiece 1 is being rotated.

[0040] Moreover, the distortion correction device 10 includes a rotation angle sensor 11 for detecting the rotation angle (phase) of the workpiece 1. The rotation angle sensor 11 may be, for example, a rotary encoder.

[0041] The distortion straightening device 10 also includes a pressing member 12 that is movable in the longitudinal direction of the workpiece 1 and can press the workpiece 1 at any position in the longitudinal direction of the workpiece 1. The pressing member 12 is raised and lowered by a hydraulic cylinder (not shown). The hydraulic cylinder is connected to a hydraulic unit (not shown), and the rod of the hydraulic cylinder is extended and contracted by the operation of the hydraulic unit. The pressing member 12 is moved in the longitudinal direction of the workpiece 1 by a pressing member moving mechanism (not shown) and a first driving device that drives the mechanism.

[0042] The distortion correction device 10 is movable in the longitudinal direction of the workpiece 1 and has two receiving members 13, 14 for receiving the workpiece 1 at two points when the workpiece 1 is pressed. In this embodiment, the distance between the two receiving members 13, 14 is constant. The distance between the two receiving members 13, 14 may be variable. The two receiving members 13, 14 are moved in the longitudinal direction of the workpiece 1 by a receiving member moving mechanism (not shown) and a second driving device that drives the mechanism.

[0043] The distortion correction device 10 also includes an ECU (Electronic Control Unit) 15 as a control device. 1 ~Q 8 ((Q 1 )~(Q 5 ), the rotation angle sensor 11, the workpiece rotation drive device, the hydraulic unit, the first drive device, the second drive device, etc. are connected to an ECU 15.

[0044] [3-2] Details of the processing in step S1 In this embodiment, in the first distortion correction process, five linear sensors (Q 1 )~(Q 5 ) is used, but for the detailed description of the processing in steps S1 and S2, for convenience of explanation, eight linear sensors Q 1 ~Q 8 In the description of the processing in steps S1 and S2, eight linear sensors Q 1 ~Q 8 These are referred to as the first to eighth linear sensors from the side of one end 1a of the workpiece 1.

[0045] The ECU 15 rotates the workpiece 1 around the central axis 5. The ECU 15 detects the first to eighth linear sensors Q 1 ~Q 8 and phase information detected by the rotation angle sensor 11. This provides position information for each phase at the eight distortion measurement positions.

[0046] The ECU 15 calculates the difference between the maximum and minimum values ​​of the position information for each distortion measurement position (hereinafter referred to as the "PP value"). Since the PP value is equivalent to twice the value of the distortion amount, the ECU 15 essentially calculates the distortion amount.

[0047] [3-3] Details of the processing in step S2 ECU15 is the 1st to 8th linear sensors Q 1 ~Q 8 Then, the ECU 15 identifies the linear sensor with the maximum PP value among the first to third linear sensors Q. 1 ~Q 3 Determine whether it is one of the following.

[0048] The linear sensors with the largest PP value are the first to third linear sensors Q 1 ~Q 3 In other words, if the linear sensor with the largest PP value is not one of the 4th to 8th linear sensors Q 1 ~Q 8 If so, the ECU 15 calculates the amount of vertical runout and the amount of horizontal runout at each strain measurement position as follows.

[0049] Here, the linear sensor with the largest PP value is the sixth linear sensor Q. 6 For convenience of explanation, the case where all the linear sensors Q 1 ~Q 8 The strain measurement positions are not those corresponding to the 5th to 7th linear sensors Q 5 ~Q 7 A method for calculating the vertical shake amount and the horizontal shake amount of the distortion measurement position corresponding to the distortion measurement position will be described below.

[0050] FIG. 5 shows the relationship between the phase information detected by the rotation angle sensor 11 and the fifth to seventh linear sensors Q 5 ~Q 7 1 is a graph showing an example of position information detected by the

[0051] FIG. 5A shows the fifth linear sensor Q 55B shows a graph of the sixth linear sensor Q 6 5C shows a graph of the seventh linear sensor Q 7 4 shows a graph for

[0052] In this example, the fifth linear sensor Q 5 The PP value of the sixth linear sensor Q is 100 [μm]. 6 The PP value of the seventh linear sensor Q is 200 [μm]. 7 The PP value is 50 [μm].

[0053] As shown in FIG. 6, the ECU 15 detects the sixth linear sensor Q 6 The phase θa at which the phase information is maximum is set as the 0° work phase. 5 6B shows a graph of the sixth linear sensor Q 6 6C shows a graph of the seventh linear sensor Q 7 4 shows a graph for

[0054] And the ECU 15 detects each linear sensor Q 1 ~Q 8 The phase in the graph of the position information versus the phase information is converted into a work phase. The work phase is a phase used to determine the work rotation angle during pressing. The work rotation angle during pressing will be described later.

[0055] Next, the ECU 15 detects the linear sensor Q 1 ~Q 8 For each measurement, the point at which the position information is maximum in the graph showing the position information versus the phase information is plotted on the polar coordinates using half the PP value of that point and the workpiece phase of that point. 5 7B is a graph of the sixth linear sensor Q 6 7C is a graph of the seventh linear sensor Q 710 is a graph showing the amount of strain (strain vector) of the work 1 at each strain measurement position, expressed in polar coordinates (PP value / 2 [μm], work phase [degrees]).

[0056] In the example of Figure 7, linear sensor Q 5 The strain vector obtained from the detection value of the linear sensor Q is (50, 30°). 6 The strain vector obtained from the detection value of the linear sensor Q is (100,0°). 7 The distortion vector obtained from the detected values ​​is (25, 45°).

[0057] Next, the ECU 15 detects the linear sensor Q 1 ~Q 8 At each measurement (at each distortion measurement position), the vertical axis component of the distortion vector expressed in polar coordinates is calculated as the vertical distortion amount, and the horizontal axis component is calculated as the horizontal distortion amount. 5 8B is a graph of the sixth linear sensor Q 6 8C is a graph of the seventh linear sensor Q 7 3 is a graph of

[0058] The vertical strain amount is the amount of strain obtained by decomposing the strain vector in the 0° or 180° direction of the work phase. The horizontal strain amount is the amount of strain obtained by decomposing the strain vector in the 90° or 270° direction of the work phase. Therefore, the vertical strain amount and the horizontal strain amount can be positive or negative.

[0059] In the example of Figure 8, linear sensor Q 5 The vertical strain obtained from the detection value is 43 [μm] (= 50·COS30°), and the horizontal strain is 25 [μm] (= 50·COS60°). 6 The vertical strain obtained from the detection value is 100[μm](=100·COS0°), and the horizontal strain is 0[μm](=100·COS90°). 7 The vertical strain obtained from the detected values ​​is 17 [μm] (= 25·COS45°), and the horizontal strain is 17 [μm] (= 25·COS45°).

[0060] By plotting the amount of longitudinal strain at each strain measurement position in a two-dimensional space with the longitudinal position of the workpiece 1 on the horizontal axis and the amount of longitudinal strain on the vertical axis and connecting adjacent points with straight lines, a line graph of the amount of longitudinal strain versus the longitudinal position of the workpiece 1 is obtained. Furthermore, by plotting the amount of lateral strain at each strain measurement position in a two-dimensional space with the longitudinal position of the workpiece 1 on the horizontal axis and the amount of lateral strain on the vertical axis and connecting adjacent points with straight lines, a line graph of the amount of lateral strain versus the longitudinal position of the workpiece 1 is obtained.

[0061] FIG. 9A shows the sixth and seventh linear sensors Q 6 ~Q 7 FIG. 9B is a line graph showing the amount of longitudinal strain with respect to the longitudinal position of the workpiece 1, obtained from the amount of longitudinal strain with respect to the sixth to seventh linear sensors Q 6 ~Q 7 1 is a line graph showing the amount of lateral strain versus the longitudinal position of the workpiece 1, obtained from the amount of lateral strain versus the longitudinal position.

[0062] The linear sensors with the largest PP value are the first to third linear sensors Q 1 ~Q 3 If the present invention is one of the above, the ECU 15 calculates the amount of longitudinal strain and the amount of lateral strain at each strain measurement position as follows.

[0063] When pressing the tooth portion 2 of the work 1, as shown in Figures 10A to 10D, it is necessary to press the work 1 at a rotation angle (phase) where the flat surface 4 of the work 1 is parallel or perpendicular to the floor surface on which the distortion correction device 10 is installed. This is because, as shown in Figure 10E, if the tooth portion 2 of the work 1 is pressed at a rotation angle (phase) where the flat surface 4 of the work 1 is oblique to the floor surface, the work 1 will rotate.

[0064] Therefore, in this embodiment, the linear sensors with the largest PP value are the first to third linear sensors Q 1 ~Q 3 In the case where the workpiece 1 is one of the above, as shown in FIG. 11, the rotation angle at which the flat surface 4 of the workpiece 1 is parallel to the floor surface and faces upward is set to 0° of the workpiece phase.

[0065] Here, the linear sensor with the largest PP value is the second linear sensor Q. 2 For convenience of explanation, the case where all the linear sensors Q 1 ~Q 8 The strain measurement positions are not those corresponding to the first to third linear sensors Q 1 ~Q 3 A method for calculating the amount of vertical distortion and the amount of horizontal distortion at the distortion measurement position corresponding to the above will be described.

[0066] FIG. 12 shows the relationship between the phase information detected by the rotation angle sensor 11 and the first to third linear sensors Q 1 ~Q 3 FIG. 12A is a graph showing an example of position information detected by the first linear sensor Q. 1 12B is a graph of the second linear sensor Q 2 12C is a graph of the third linear sensor Q 3 3 is a graph of

[0067] In FIG. 12, the phase range surrounded by the dashed line 21 is the linear sensor Q 1 ~Q 3 This is the point where the position of the flat surface 4 of the tooth portion 2 is detected by the linear sensor Q. 1 ~Q 3 When the position of flat surface 4 is detected by linear sensor Q 1 ~Q 3 The position information output from the linear sensor Q is when the position of a surface other than the flat surface 4 of the workpiece 1 is being output. 1 ~Q 3 Therefore, in this embodiment, the linear sensor Q 1 ~Q 3 When the position information detected by the linear sensor Q is greater than a predetermined threshold A (A>0), 1 ~Q 3 The position information detected by is treated as a missing value with no value.

[0068] In this example, the first linear sensor Q 1 The PP value of the second linear sensor Q is 100 [μm]. 2 The PP value of the third linear sensor Q is 200 [μm]. 3 The PP value is 50 [μm].

[0069] As shown in FIG. 13, the ECU 15 sets the phase θb ​​at the center of the phase section treated as a missing value as 0° of the work phase. 1 ~Q 8 The phase in the graph of the position information versus the phase information is converted to the work phase.

[0070] FIG. 13A shows the first linear sensor Q 1 13B is a graph of the second linear sensor Q 2 13C is a graph of the third linear sensor Q 3 3 is a graph of

[0071] In the subsequent processing, the linear sensors with the largest PP values ​​are the 4th to 8th linear sensors Q 1 ~Q 8 Since the process is the same as the process when it is one of the above, the description thereof will be omitted (see FIGS. 7 to 9).

[0072] [4] Details of step S3 The process of step S3 will be described in detail below. In the detailed description of the process of step S3, an example will be described in which five linear sensors (Q1) to (Q5) shown in Fig. 4 as (Q1) to (Q5) are used. In the detailed description of the process of step S3, the five linear sensors (Q1) to (Q5) will be referred to as the first to fifth linear sensors from the one end 1a side of the workpiece 1.

[0073] FIG. 14 is a flowchart showing a detailed procedure of the longitudinal distortion correcting process in step S3 of FIG.

[0074] The maximum value among the absolute values of the vertical deflection amounts for each of the linear sensors (Q1) to (Q5) (for each strain measurement position) calculated in step S2 of FIG. 3 shall be referred to as the "initial maximum vertical strain amount Va". Also, let B (B > 0) be a predetermined threshold for vertical strain pass determination, and C (0 < B < C) be a predetermined threshold for vertical strain fail determination.

[0075] The ECU 15 determines whether the maximum vertical strain amount Va is less than the threshold B (Va < B), greater than the threshold C (Va > C), or within the range of B or more and C or less (B ≤ Va ≤ C) (step S11).

[0076] If Va < B, the ECU 15 determines that the vertical strain is qualified (step S12) and ends the vertical strain correction process.

[0077] If Va > C, the ECU 15 determines that the vertical strain is unqualified (step S13) and ends the vertical strain correction process. In this case, it may be determined that it is impossible to correct the strain of the workpiece 1, and the horizontal strain correction process in step S4 of FIG. 3 may not be performed.

[0078] If B ≤ Va ≤ C, the ECU 15 determines that it is possible to correct the strain of the workpiece 1 and proceeds to step S14. In step S14, the ECU 15 performs a press condition search process for obtaining press conditions suitable for efficiently reducing the vertical strain amount. The press conditions searched by the press condition search process are, in this embodiment, the press position, the workpiece receiving position, and the press stroke amount. In this embodiment, two receiving positions separated from each other by a predetermined interval are set as the workpiece receiving positions.

[0079] Next, the ECU 15 presses the workpiece 1 under the pressing conditions obtained in step S14 (step S15). Referring to FIG. 4, the receiving members 13 and 14 are arranged at the workpiece receiving positions obtained in step S14, and the pressing member 12 is arranged at the pressing position obtained in step S14. Then, the pressing member 12 is pushed in by the pressing stroke amount obtained in step S14. In this embodiment, the movement of the receiving members 13 and 14 and the pressing member 12 is performed automatically, but it may be performed manually.

[0080] At this time, the rotation angle of the workpiece 1 is set to the workpiece phase at which the absolute value of the longitudinal strain amount newly calculated for each strain measurement position is the maximum among 0° or 180° of the workpiece phase.

[0081] Next, the ECU 15 re-measures the strain amount for each strain measurement position (for each of the linear sensors (Q 1 ) to (Q 5 )) and calculates the longitudinal strain amount and the lateral strain amount for each strain measurement position (step S16). As a result, the longitudinal strain amount and the lateral strain amount for each strain measurement position are updated. The maximum value among the absolute values of the longitudinal strain amounts of the strain measurement positions calculated in step S16 is referred to as the "maximum longitudinal strain value Vb".

[0082] Next, the ECU 15 determines whether or not the maximum longitudinal strain value Vb is less than a predetermined threshold D (D > 0) (step S17). The threshold D may be the same value as the threshold B or a different value from the threshold B. If Vb ≥ D (step S17: NO), the ECU 15 returns to step S14.

[0083] In step S17, if it is determined that Vb < D (step S17: YES), the ECU 15 determines that the longitudinal strain is qualified (step S12) and ends the longitudinal strain correction process.

[0084] [5] Details of Step S14 FIG. 15 is a flowchart showing the detailed procedure of the pressing condition search process in step S14 of FIG. 14.

[0085] The ECU 15 acquires the amount of longitudinal strain for each strain measurement position (each of the linear sensors (Q1) to (Q5)) (step S21). When the process has moved from step S11 in FIG. 14 to step S14 (step S21 in FIG. 15), the ECU 15 acquires the amount of longitudinal strain for each strain measurement position calculated in step S2 in FIG. 3. When the process has moved from step S17 in FIG. 14 to step S14 (step S21 in FIG. 15), the ECU 15 acquires the amount of longitudinal strain for each strain measurement position calculated in step S16 in FIG. 14.

[0086] A broken line K0 in FIG. 16 is a broken line graph showing an example of the amount of longitudinal strain at each strain measurement position acquired in step S21.

[0087] Next, the ECU 15 calculates the amount of elastic deformation (post-press deformation) when the straight reference bar is pressed by simulation (step S22). In this embodiment, the post-press deformation is calculated using a mathematical model. In this embodiment, a deflection model of a beam supported at both ends is used as the mathematical model. The amount of elastic deformation when the reference bar is pressed may be calculated using CAE (Computer Aided Engineering).

[0088] FIG. 17 is a schematic diagram showing a deflection model of a beam supported at both ends.

[0089] One end of the beam (long member) before pressing that extends horizontally is set as the origin O, and in a coordinate system with x on the horizontal axis and y on the vertical axis, x is the distance from the origin O in the x direction. 2 The first workpiece receiving position is located at a distance of x from the origin O. 3 The second workpiece receiving position is located at a distance of x from the origin O. 1 Assume that a press load F is acting at a position distant from the target.

[0090] The definitions of the symbols in FIG. 17 are as follows:

[0091] x 1 : Press position (x-distance from the origin to the press position [μm]) x2 : First workpiece receiving position (x-distance from the origin to the first workpiece receiving position [μm]) x 3 : Second workpiece receiving position (x-direction distance from the origin to the second workpiece receiving position [μm]) θ 1 : Deflection angle of the part of the beam from one end to the first workpiece receiving position after pressing θ 2 : Deflection angle of the part of the beam from the second workpiece receiving position to the other end after pressing y: deformation amount after pressing [μm] F: Press load [N] The deformation amount (elastic deformation amount) y of the beam after pressing at a position a distance x away from the origin O in the x direction is expressed by the following equation (1).

[0092]

number

[0093] In formula (1), E is Young's modulus [N / μm 2 ] and Iz is the second moment of area [μm 4 ].

[0094] From equation (1), the press position x 1 , Workpiece receiving position x 2 ,x 3 and F / 6EIz[1 / μm -2 ], the deformation amount y after pressing for the x-direction position can be calculated. 1 , Workpiece receiving position x 2 ,x 3 and F / 6EIz are referred to as adjustment parameters. F / 6EIz is an example of "load-related information" in this disclosure.

[0095] Also, from equation (1), the workpiece receiving position x 2 ,x 3 It can be seen that the deformation amount y after pressing at the workpiece receiving position x becomes 0. 2 ,x 3The post-press deformation amount y of the long member calculated so that the post-press deformation amount y at the workpiece receiving position is 0 is referred to as the post-press deformation amount y based on the workpiece receiving position. On the other hand, the post-press deformation amount y of the long member calculated so that the post-press deformation amount y at both ends of the long member is 0 is referred to as the post-press deformation amount y based on the both ends.

[0096] The process of step S22 will now be described in detail.

[0097] First, the ECU 15 calculates the post-press deformation amount y of a straight reference bar having the same length as the workpiece 1 as a workpiece receiving reference, using the given adjustment parameters and the above-mentioned formula (1).

[0098] When the process proceeds from step S21 to step S22, the ECU 15 sets the initial value of the adjustment parameter (press position x 1 , Workpiece receiving position x 2 ,x 3 and the initial value of F / 6EIz) and equation (1), calculate the post-press deformation amount y of the workpiece receiving reference of the reference bar for each strain measurement position (the position of each linear sensor (Q1) to (Q5)).

[0099] A curve K1 in FIG. 18 is a line graph showing an example of the post-press deformation amount y of the workpiece receiving standard of the reference bar calculated in step S22.

[0100] Next, the ECU 15 converts the post-press deformation amount y of the reference bar based on the workpiece receiving standard into the post-press deformation amount y based on both ends of the reference bar.

[0101] This conversion is performed as follows. That is, a linear equation [y={(yb-ya) / xb}+ya] of a straight line connecting both ends (0,ya) and (xb,yb) of the graph of the post-press deformation amount y of the reference bar based on the workpiece support is created. Next, the value y of the linear equation at each position is subtracted from the post-press deformation amount y at the corresponding position of the reference bar based on the workpiece support. This results in the post-press deformation amount y based on both ends as shown by the curve K2 in FIG. 18.

[0102] When the process of step S22 is completed, the ECU 15 calculates the remaining amount of distortion (predicted value) of the workpiece 1 after pressing (step S23). Specifically, the ECU 15 adds the post-press deformation amount based on both ends of the reference bar at the corresponding position to the longitudinal strain amount at each strain measurement position of the work 1, and plots the added value at each strain measurement position in the coordinate space, as shown in Fig. 19. Then, the ECU 15 calculates the post-press residual strain amount for the longitudinal position of the work 1 by connecting the plotted points with straight lines.

[0103] In FIG. 19, the broken line K0 is a graph showing the amount of longitudinal strain at each position of the work 1, the broken line K2' is a graph showing the amount of deformation after pressing based on both ends of the reference bar, and the broken line K3 is a graph showing the amount of remaining strain after pressing of the work 1. However, the broken line K2' in FIG. 19 is a broken line graph created based on the curve K2 in FIG. 18. In other words, the amount of deformation after pressing at positions corresponding to each strain measurement position of the work 1 is extracted from the curve K2 in FIG. 18. The extracted amount of deformation after pressing at each strain measurement position is plotted in coordinate space. The broken line K2' is obtained by connecting the plotted points with straight lines.

[0104] Next, the ECU 15 calculates the sum of squares of the remaining amount of distortion after pressing at each distortion measurement position (step S24).

[0105] Linear sensor (Q 1 ), (Q 2 ), (Q 3 ), (Q 4 ) and (Q 5 ) The residual distortion after pressing at the corresponding distortion measurement positions is R 1 , R 2 , R 3 , R 4 and R 5 Then, the sum of squares U of the remaining strain at each strain measurement position after pressing is expressed by the following equation (2).

[0106]

number

[0107] Next, the ECU 15 determines whether the sum of squares U is less than a predetermined threshold value G (G>0) (step S25).

[0108] If the sum of squares U is equal to or larger than G (step S25: NO), the ECU 15 changes the adjustment parameters (step S26). Specifically, the ECU 15 adjusts the press position x so that the sum of squares U becomes the minimum value by using, for example, a GRG nonlinear (generalized reduced gradient method). 1 , Workpiece receiving position x 2 ,x 3 and F / 6EIz. Note that the ECU 15 may change the adjustment parameters by using a method other than the GRG nonlinear method so that the sum of squares U becomes the minimum value.

[0109] After that, the ECU 15 returns to step S22 and executes the processes from step S22 onward again. When moving from step S26 to step S22, the ECU 15 calculates the post-press deformation amount y based on the workpiece receiving reference for each strain measurement position using the adjustment parameters changed in step S26 and formula (1). Then, the post-press deformation amount y based on the workpiece receiving reference is converted into the post-press deformation amount y based on both ends.

[0110] In step S25, if it is determined that the sum of squares U is less than G (step S25: YES), ECU 15 converts the finally set F / 6EIz into the deformation amount required to remove the distortion of workpiece 1 (hereinafter referred to as "distortion removal deformation amount DA") (step S27).

[0111] x 1 ',x 2 ',x 3 ' and α are the final settings, x 1 , x 2 , x 3 and F / 6EIz, the ECU 15 calculates the finally set F / 6EIz (=α) [1 / μm -2In other words, the ECU 15 calculates the distortion correction deformation amount DA such that the sum of squares U is less than G.

[0112]

number

[0113] In the following, x in formula (1) is x 1 ≦x <x 3 The formula for y within the range is called the formula of interest. Formula (3) is derived from the formula of interest as follows. That is, first, 1 , x 2 , x 3 and F / 6EIz, respectively. 1 ',x 2 ',x 3 ' and α, and replace y and x in the calculation formula with DA and x, respectively. 1 '. Then, put an absolute value symbol on the entire right hand side of the resulting equation.

[0114] For example, the final position x 1 , x 2 and x 3 are 100,000 [μm], 0 [μm], and 200,000 [μm], respectively, the distortion correction deformation amount DA is expressed by the following equation (4).

[0115]

number

[0116] Next, the ECU 15 converts the distortion correction deformation amount DA into a press stroke amount PS to be obtained by plastic deformation (step S28).

[0117] Specifically, the ECU 15 converts the deformation change amount DA obtained in step S27 into the press stroke amount PS based on the relationship between the deformation amount DA and the press stroke amount PS, which is obtained in advance by an experiment. An example of the relationship between the deformation amount DA and the press stroke amount PS is shown in FIG.

[0118] When the process of step S28 is completed, the ECU 15 proceeds to step S4 in FIG. 3. The horizontal distortion correction process of step S4 in FIG. 3 is almost the same as the vertical distortion correction process of step S3 in FIG. 3, so detailed description will be omitted. In the horizontal distortion correction process of step S4 in FIG. 3, the horizontal distortion amount is used instead of the vertical distortion amount in the vertical distortion correction process of step S3 in FIG. 3, and thresholds A to E suitable for the horizontal distortion amount are used. In the process corresponding to step S15 in FIG. 14, the rotation angle of the workpiece 1 is set to the workpiece phase of 90° or 270° at which the absolute value of the horizontal distortion amount calculated most recently for each distortion measurement position is maximum. Other points are the same as the vertical distortion correction process.

[0119] In this embodiment, the straight reference bar is set at a given press position x 1 , given receiving position x 2 ,x 3 The amount of elastic deformation of the reference bar when it is elastically deformed by pressing with a given F / 6EIz (load-related information) is calculated by simulation. Next, based on the amount of strain (longitudinal strain or lateral strain) and the amount of elastic deformation, the amount of remaining strain is calculated assuming that the work 1 is elastically deformed by the amount of elastic deformation. Then, the press position x where the amount of remaining strain (in this embodiment, the sum of the squares of the amount of remaining strain at each strain measurement position) falls within the allowable range is calculated. 1 and receiving position x 2 ,x 3 is obtained.

[0120] This makes it possible to determine the pressing position and receiving position suitable for correcting the distortion of the workpiece 1 without relying on the empirical knowledge of a skilled technician. This makes it possible to properly correct the distortion of the workpiece 1. This also makes it possible to correct the distortion of a long workpiece by a new method different from the method described in Patent Document 1.

[0121] Furthermore, by acquiring load-related information (F / 6EIz in this embodiment) when the remaining distortion amount is within the allowable range, it becomes possible to calculate the press load and press stroke amount suitable for correcting the distortion of the workpiece 1. This makes it possible to correct the distortion of the workpiece 1 more appropriately.

[0122] As mentioned above, the straight reference bar is placed at a given press position x 1 , given receiving position x 2 ,x 3 The amount of elastic deformation of the reference bar when it is pressed and elastically deformed at a given F / 6EIz (load-related information) may be calculated using a deflection model of a beam supported at both ends or using CAE, but it may also be calculated by other methods.

[0123] Furthermore, the number and arrangement positions of the linear sensors used in the first distortion correction process and the second distortion correction process can be set arbitrarily.

[0124] Furthermore, in the above-described embodiment, the workpiece 1 is a rack shaft, but the workpiece may be a member other than a rack shaft as long as it is an elongated member.

[0125] Although the embodiments of the present disclosure have been described in detail above, these are merely specific examples used to clarify the technical content of the present disclosure, and the present disclosure should not be interpreted as being limited to these specific examples, and the scope of the present disclosure is limited only by the appended claims. [Explanation of symbols]

[0126] Reference Signs List 1: Workpiece, 1a: First end, 1b: Second end, 2: Tooth portion, 2a: Rack teeth, 3: Thread portion, 3a: Male thread, 4: Flat surface, 4a: Back surface, 5: Central axis, 10: Distortion correction device, 11: Rotation angle sensor, 12: Pressing member, 13, 14: Receiving member, 15: ECU

Claims

1. A method for correcting distortion of a long workpiece, comprising the steps of: acquiring strain amounts at a plurality of locations in a longitudinal direction of the workpiece; A step of calculating, by simulation, an amount of elastic deformation of a straight reference bar when the reference bar is elastically deformed by pressing the reference bar at a given pressing position, a given receiving position, and given load-related information; calculating a residual strain amount when the workpiece is assumed to be elastically deformed by the elastic deformation amount based on the strain amount and the elastic deformation amount; and acquiring the pressing position and the receiving position when the residual distortion amount is within an allowable range.

2. The method for correcting distortion of a long workpiece as described in claim 1, further comprising the step of supporting the workpiece at the receiving position when the remaining distortion amount is within an acceptable range, and pressing the workpiece at the pressing position when the remaining distortion amount is within an acceptable range, thereby correcting distortion of the workpiece.

3. acquiring the load-related information when the residual distortion amount is within an allowable range; calculating a deformation amount for distortion relief required to remove distortion of the workpiece from the load-related information; The method for straightening a long workpiece according to claim 1 , further comprising a step of calculating a press stroke amount for obtaining the distortion correction deformation amount by plastic deformation.

4. 4. The method for correcting distortion of a long workpiece as described in claim 3, comprising the steps of supporting the workpiece at the receiving position when the remaining distortion amount is within an acceptable range, and pressing the workpiece by the press stroke amount at the pressing position when the remaining distortion amount is within an acceptable range, thereby correcting distortion of the workpiece.

5. A method for correcting distortion of a long workpiece according to any one of claims 1 to 4, wherein the step of calculating the elastic deformation amount of the reference bar and the step of calculating the remaining distortion amount are repeated until the remaining distortion amount falls within an allowable range.

6. The amount of distortion at a plurality of points in the longitudinal direction of the workpiece is a two-end reference amount of distortion in which the amount of distortion at both ends of the workpiece is zero, A method for correcting distortion of a long workpiece as described in claim 3, wherein in the process of calculating the elastic deformation amount of the reference bar, a given press position, a given receiving position, and given load-related information are used to calculate an elastic deformation amount based on a receiving position standard at which the elastic deformation amount of the receiving position of the reference bar is zero, and from the elastic deformation amount based on the receiving position standard, an elastic deformation amount based on both ends of the reference bar is zero is calculated, and the elastic deformation amount based on the both ends standard is calculated as the elastic deformation amount of the reference bar.

7. A long workpiece distortion correction device that corrects distortion by pressing a long workpiece, A plurality of sensors for measuring the amount of distortion of the workpiece at a plurality of points in a longitudinal direction of the workpiece; a pressing member that is movable in the longitudinal direction of the work and that can press the work at any position in the longitudinal direction of the work; a receiving member that is movable in the longitudinal direction of the workpiece and receives the workpiece when the workpiece is pressed; A distortion correction device for a long workpiece, wherein the pressing position of the pressing member and the receiving position of the receiving member are set based on the pressing position and the receiving position acquired in claim 1, respectively.

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