A method for straightening pipe parts

Abstract

The present invention discloses a method for straightening pipe parts, comprising the following steps: step 1, detecting data and obtaining the initial straightness of the inner hole of the pipe parts, the initial straightness of the outer circle of the pipe parts and the center coordinates of the detected section; step 2, establishing the relationship between the inner hole straightness and the outer circle straightness through the center coordinates of the section; step 3, calculating the correction angle range and the distance range after correction of the center coordinates of the outer circle section that meets the inner hole straightness; step 4, correcting the pipe parts and judging whether the correction is qualified; step 5, verification. The present invention optimizes the process flow as a whole, improves the straightening efficiency, shortens the production cycle time, and reduces the straightening cost.

Description

Technical Field

[0001] The invention relates to the technical field of straightening of pipe parts, and in particular to a method for straightening pipe parts. Background Art

[0002] Straightening machines are equipment used in the machinery industry to straighten pipe parts that are commonly used in the machinery industry due to thermal deformation during processing and deformation caused by external forces during transportation. The high or low straightening efficiency is one of the most important factors in evaluating the performance of the straightening machine. Generally, the straightening machine is divided into a detection process and a correction process during the entire straightening process. The detection process and the correction process are performed alternately to correct the pipe parts until the correction is qualified.

[0003] However, in the process of inspecting pipe parts, it is necessary to calibrate multiple sections of the inner hole of the pipe parts, and then inspect the multiple sections in turn. Only after all sections have been inspected, can the inner hole straightness be fitted and evaluated, and then the pipe parts are installed on a straightening machine for correction. After correction, it is necessary to inspect the corrected pipe parts again to obtain the corrected inner hole straightness and compare it with the inner hole straightness obtained for the first time. If they are consistent, the pipe parts are calibrated and qualified. If not, the pipe parts continue to be calibrated.

[0004] Therefore, during the straightening process, pipe parts need to be repeatedly inspected and corrected, which is not only cumbersome but also seriously affects the overall straightening efficiency. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a method for straightening pipe parts that can improve the straightening efficiency.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for straightening a pipe part comprises the following steps:

[0008] Step 1, detect data and obtain the initial straightness of the inner hole of the pipe parts and the initial straightness of the outer circle of the pipe parts and the center coordinates of the detected sections: calibrate multiple inner hole sections and outer circle sections for the inner hole and outer circle of the pipe parts respectively, the inner hole section and the outer circle section correspond to each other and are located in the same plane, and perform data detection on each inner hole section and outer circle section respectively, fit the corresponding inner hole section center coordinates through the data detected by each inner hole section, and use the straightness evaluation criteria to obtain the initial straightness of the inner hole from the center coordinates of all the inner hole sections; and fit the corresponding outer circle section center coordinates through the data detected by each outer circle section, and use the straightness evaluation criteria to obtain the initial straightness of the outer circle from the center coordinates of all the outer circle sections;

[0009] Step 2: Establish the relationship between the inner hole straightness and the outer circle straightness through the inner hole section center coordinates and the outer circle section center coordinates: Cut the same section according to the initial straightness of the inner hole and the initial straightness of the outer circle, take this section and take the ideal axis of the inner hole as the origin (0,0) to establish a global rectangular coordinate system. In the establishment of the global rectangular coordinate system, set the auxiliary coordinate point (ΔX, ΔY), set R as the maximum value allowed for the inner hole straightness, and in this section, set the inner hole section center coordinate qualified inclusion area that meets the inner hole straightness as X. 2 +Y 2 ≤R 2 ;

[0010] In this section, let the coordinates of the center of the inner hole section be (X1, Y1), let the coordinates of the center of the outer circle section be (X2, Y2), and let the auxiliary coordinates ΔX = X2-X1, ΔY = Y2-Y1. Since the coordinates of the center of the inner hole and the center of the outer circle are in translation relationship in this section during calibration, the qualified inclusion area of ​​the center of the outer circle section that meets the straightness of the inner hole in this section is (X-ΔX). 2 -(Y-ΔY) 2 ≤R 2 , convert the qualified inclusion area of ​​the inner hole section circle center coordinates that meet the inner hole straightness into the qualified inclusion area of ​​the outer circle section circle center coordinates that meet the inner hole straightness, and extend it to all sections and circle center coordinates, and thereby establish the relationship between the inner hole straightness and the outer circle straightness;

[0011] Step 3: Calculate the correction angle range and distance range of the center coordinates of the outer circle section that meet the straightness of the inner hole: According to step 2, take the center coordinates (X2, Y2) of the outer circle section as the origin and the straight line passing through (ΔX, ΔY) and (X2, Y2) in the global coordinate system as the X-axis to establish a local coordinate system;

[0012] When the coordinates of the center of the hole section in the global coordinate system (X1, Y1) are in the first and fourth quadrants in the global coordinate system, the coordinates of each point are converted in the local coordinate system: (X2, Y2) is converted to (O2, O2), (ΔX, ΔY) is converted to

[0013]

[0014] The equation of the qualified inclusion area of ​​the center coordinates of the outer circle section that meets the inner hole straightness is converted into In order to correct (O2, O2) to within the qualified inclusion area, the correction angle θ is:

[0015] At this time, the correction range β is:

[0016] When the coordinates of the center of the hole section in the global coordinate system (X1, Y1) are in the second and third quadrants in the global coordinate system, the coordinates of each point are converted in the local coordinate system: (X2, Y2) is converted to (02, 02), (ΔX, ΔY) is converted to The equation of the contained area of ​​the center coordinates of the outer circle section that meets the straightness of the inner hole is converted into In order to correct (02, 02) to the qualified inclusion area, the correction angle θ is:

[0017] At this time, the correction range β is:

[0018] In the local coordinate system, correct the length L of the tube parts:

[0019] When the coordinates of the center of the hole section in the global coordinate system (X1, Y1) are in the first and fourth quadrants in the global coordinate system, the equation group is established:

[0020]

[0021] Or when the coordinates of the center of the hole section in the global coordinate system (X1, Y1) are in the second and third quadrants in the global coordinate system, establish the equation group:

[0022]

[0023] Solve the coordinates of the two intersection points, then the minimum corrected length is the distance from (02, 02) to the first intersection point, and the maximum corrected length is the distance from (02, 02) to the second intersection point. After the correction angle is selected, the correction range is between the minimum distance and the maximum distance. Repeat the above equations and apply them to all cross sections to fit a new outer circle straightness and a qualified inner hole straightness.

[0024] Step 4, calibrate the pipe parts and judge whether the calibration is qualified: select the calibration angle by calculation and perform the calibration process on the pipe parts. After the calibration, fit the corresponding coordinates of the center of the outer circle section by detecting the outer circle section and evaluate the corrected outer circle straightness. Compare the corrected outer circle straightness with the new outer circle straightness in step 3. If the two are consistent, the calibration is qualified. Otherwise, repeat the calibration steps until the calibration is qualified and proceed to the next step.

[0025] Step 5, verification: inspect the inner hole section of the qualified pipe parts, fit the corresponding inner hole section center coordinates and evaluate the corrected inner hole straightness, compare the corrected inner hole straightness with the qualified inner hole straightness in step 3, if the two are consistent, it is verified that the pipe parts are qualified, otherwise, return to step 4.

[0026] Further, in step one, in step one, the straightness evaluation criteria include two end point connection method, least square method and minimum area inclusion method.

[0027] Furthermore, in step 1, the device for detecting the initial straightness of the outer circle adopts a contact or non-contact detection device.

[0028] Furthermore, in step one, the device for detecting the initial straightness of the inner hole adopts a contact or non-contact detection device.

[0029] Furthermore, in step 1, the initial straightness detection of the inner hole and the initial straightness detection of the outer circle are performed synchronously or asynchronously. The synchronous detection can shorten the detection time and improve the efficiency of straightening.

[0030] Furthermore, in step one, the data of each inner hole section detection is fitted with the corresponding inner hole section center coordinates using the least squares circle method, and the data of each outer circle section detection is fitted with the corresponding outer circle section center coordinates using the least squares circle method.

[0031] Furthermore, in step 2, the ideal axis of the inner hole is the least square center line of the ideal tube part.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] 1. The present invention is a method for detecting and correcting the same type of pipe parts. First, the initial straightness of the inner hole and the initial straightness of the outer circle of a pipe part of the same type of pipe parts are obtained, and the same section is cut according to the initial straightness of the inner hole and the initial straightness of the outer circle. Under ideal conditions, the qualified inclusion area of ​​the inner hole straightness is obtained according to the formula, and then the qualified inclusion area of ​​the inner hole straightness is converted into the qualified inclusion area of ​​the outer circle straightness according to the formula according to the simultaneous translation of the inner hole section and the outer circle section during correction. This design is to initially establish a connection between the inner hole straightness and the outer circle straightness;

[0034] Then, by establishing a coordinate system, the correction angle of the center coordinates of the outer circle of the cross section and the corrected distance are calculated respectively. Then, a certain correction angle is specified for correction. After correction, the outer circle straightness is detected to obtain a qualified inner hole straightness. In the prior art, the outer circle straightness is a plurality of sensors arranged at intervals along the length direction of the pipe part. Therefore, the outer circle straightness is quickly obtained by detecting and processing data at one time by multiple sensors, so as to judge whether the pipe part is qualified. This method can improve the detection efficiency; finally, the inner hole straightness of the part is verified by directly detecting the inner hole straightness to verify the accuracy of its correction.

[0035] 2. The present invention optimizes the overall process flow, improves the straightening efficiency, shortens the production cycle time, reduces the straightening cost, and the inner hole detection and outer circle detection can be carried out simultaneously. Therefore, the equipment for outer hole detection and the equipment for outer circle detection can be carried out simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a flow chart of a method for straightening a pipe part. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0038] This example: See Figure 1 , a method for straightening a pipe part, comprising the following steps:

[0039] Step 1, detect data and obtain the initial straightness of the inner hole of the pipe parts and the initial straightness of the outer circle of the pipe parts and the center coordinates of the detected sections: calibrate multiple inner hole sections and outer circle sections for the inner hole and outer circle of the pipe parts respectively, the inner hole section and the outer circle section correspond to each other and are located in the same plane, and perform data detection on each inner hole section and outer circle section respectively, fit the corresponding inner hole section center coordinates through the data detected by each inner hole section, and use the straightness evaluation criteria to obtain the initial straightness of the inner hole from the center coordinates of all the inner hole sections; and fit the corresponding outer circle section center coordinates through the data detected by each outer circle section, and use the straightness evaluation criteria to obtain the initial straightness of the outer circle from the center coordinates of all the outer circle sections;

[0040] Step 2: Establish the relationship between the inner hole straightness and the outer circle straightness through the coordinates of the center of the inner hole section and the center of the outer circle section: Cut the same section according to the initial straightness of the inner hole and the initial straightness of the outer circle. Under ideal conditions, take this section and take the ideal axis of the inner hole as the origin (0,0) to establish a global rectangular coordinate system. In the establishment of the global rectangular coordinate system, set the auxiliary coordinate point (ΔX, ΔY), set R as the maximum value allowed for the inner hole straightness, and in this section, set the inner hole section center coordinate qualified inclusion area that meets the inner hole straightness as X. 2 +Y 2 ≤R 2 ;

[0041] In this section, let the coordinates of the center of the inner hole section be (X1, Y1), let the coordinates of the center of the outer circle section be (X2, Y2), and let the auxiliary coordinates ΔX = X2-X1, ΔY = Y2-Y1. Since the coordinates of the center of the inner hole and the center of the outer circle are in translation relationship in this section during calibration, the qualified inclusion area of ​​the center of the outer circle section that meets the straightness of the inner hole in this section is (X-ΔX). 2 -(Y-ΔY) 2 ≤R2 , convert the qualified inclusion area of ​​the inner hole section circle center coordinates that meet the inner hole straightness into the qualified inclusion area of ​​the outer circle section circle center coordinates that meet the inner hole straightness, and extend it to all sections and circle center coordinates, and thereby establish the relationship between the inner hole straightness and the outer circle straightness;

[0042] Step 3: Calculate the correction angle range and distance range of the center coordinates of the outer circle section that meet the straightness of the inner hole: According to step 2, take the center coordinates (X2, Y2) of the outer circle section as the origin and the straight line passing through (ΔX, ΔY) and (X2, Y2) in the global coordinate system as the X-axis to establish a local coordinate system;

[0043] When the coordinates of the center of the hole section in the global coordinate system (X1, Y1) are in the first and fourth quadrants in the global coordinate system, the coordinates of each point are converted in the local coordinate system: (X2, Y2) is converted to (O2, O2), (ΔX, ΔY) is converted to

[0044]

[0045] The equation of the qualified inclusion area of ​​the center coordinates of the outer circle section that meets the inner hole straightness is converted into In order to correct (O2, O2) to within the qualified inclusion area, the correction angle θ is:

[0046] At this time, the correction range β is:

[0047] When the coordinates of the center of the hole section in the global coordinate system (X1, Y1) are in the second and third quadrants in the global coordinate system, the coordinates of each point are converted in the local coordinate system: (X2, Y2) is converted to (02, 02), (ΔX, ΔY) is converted to The equation of the contained area of ​​the center coordinates of the outer circle section that meets the straightness of the inner hole is converted into In order to correct (02, 02) to the qualified inclusion area, the correction angle θ is:

[0048] At this time, the correction range β is:

[0049] In the local coordinate system, correct the length L of the tube parts:

[0050] When the coordinates of the center of the hole section in the global coordinate system (X1, Y1) are in the first and fourth quadrants in the global coordinate system, the equation group is established:

[0051]

[0052] Or when the coordinates of the center of the hole section in the global coordinate system (X1, Y1) are in the second and third quadrants in the global coordinate system, establish the equation group:

[0053]

[0054] Solve the coordinates of the two intersection points, then the minimum corrected length is the distance from (02, 02) to the first intersection point, and the maximum corrected length is the distance from (02, 02) to the second intersection point. After the correction angle is selected, the correction range is between the minimum distance and the maximum distance. Repeat the above equations and apply them to all cross sections to fit a new outer circle straightness and a qualified inner hole straightness.

[0055] Step 4, calibrate the pipe parts and judge whether the calibration is qualified: select the calibration angle by calculation and perform the calibration process on the pipe parts. After the calibration, fit the corresponding coordinates of the center of the outer circle section by detecting the outer circle section and evaluate the corrected outer circle straightness. Compare the corrected outer circle straightness with the new outer circle straightness in step 3. If the two are consistent, the calibration is qualified. Otherwise, repeat the calibration steps until the calibration is qualified and proceed to the next step.

[0056] Step 5, verification: inspect the inner hole section of the qualified pipe parts, fit the corresponding inner hole section center coordinates and evaluate the corrected inner hole straightness, compare the corrected inner hole straightness with the qualified inner hole straightness in step 3, if the two are consistent, it is verified that the pipe parts are qualified, otherwise, return to step 4.

[0057] Preferably, in step one, the straightness evaluation criteria include two end point connection method, least square method and minimum area inclusion method.

[0058] Preferably, in step one, the device for detecting the initial straightness of the outer circle adopts a contact or non-contact detection device, which can adopt sensor detection, PSD detection, laser detection and machine vision detection, but is not limited to the above detection methods and can be applicable to all methods of measuring outer circle runout.

[0059] Preferably, in step 1, the initial straightness of the outer circle is detected by a sensor, but is not limited to the above detection method and can be applied to all methods of measuring outer circle runout.

[0060] Preferably, in step one, the device for detecting the initial straightness of the inner hole adopts a contact or non-contact detection device.

[0061] Preferably, the inner hole initial straightness detection and the outer circle initial straightness detection are performed synchronously or asynchronously. Synchronous detection can shorten the detection time and improve the efficiency of straightening.

[0062] Preferably, in step one, the data detected for each inner hole section are fitted with the corresponding coordinates of the center of the inner hole section using the least squares circle method, and the data detected for each outer circle section are fitted with the corresponding coordinates of the center of the outer circle section using the least squares circle method. The present invention is applicable to all straightness evaluation criteria, but is not limited to the least squares circle method, and other methods may be used for fitting.

[0063] Preferably, in step 2, the ideal axis of the inner hole is the least square center line of the ideal tube part.

[0064] The present invention is a method for detecting and correcting a pipe-like part. First, the initial straightness of the inner hole and the initial straightness of the outer circle of a pipe-like part of the pipe-like part are obtained, and the same section is cut according to the initial straightness of the inner hole and the initial straightness of the outer circle. Under an ideal state, a qualified inclusion area of ​​the inner hole straightness is obtained according to a formula. Then, according to the simultaneous translation of the inner hole section and the outer circle section during correction, the qualified inclusion area of ​​the inner hole straightness is converted into a qualified inclusion area of ​​the outer circle straightness according to a formula. This design is to establish a preliminary connection between the inner hole straightness and the outer circle straightness.

[0065] Then, by establishing a coordinate system, the correction angle of the center coordinates of the outer circle of the cross section and the corrected distance are calculated respectively. Then, a certain correction angle is specified for correction. After correction, the outer circle straightness is detected to obtain a qualified inner hole straightness. In the prior art, the outer circle straightness is a plurality of sensors arranged at intervals along the length direction of the pipe part. Therefore, the outer circle straightness is quickly obtained by detecting and processing data at one time by multiple sensors, so as to judge whether the pipe part is qualified. This method can improve the detection efficiency; finally, the inner hole straightness of the part is verified by directly detecting the inner hole straightness to verify the accuracy of its correction.

[0066] The present invention optimizes the overall process flow, improves the straightening efficiency, shortens the production cycle time, reduces the straightening cost, and the inner hole detection and outer circle detection can be performed simultaneously. Therefore, the equipment for outer hole detection and the equipment for outer circle detection can be performed simultaneously.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A method for straightening a pipe part, characterized in that: The following steps are involved: Step 1, detect data and obtain the initial straightness of the inner hole of the pipe parts and the initial straightness of the outer circle of the pipe parts and the center coordinates of the detected sections: calibrate multiple inner hole sections and outer circle sections for the inner hole and outer circle of the pipe parts respectively, the inner hole section and the outer circle section correspond to each other and are located in the same plane, and perform data detection on each inner hole section and outer circle section respectively, fit the corresponding inner hole section center coordinates through the data detected by each inner hole section, and use the straightness evaluation criteria to obtain the initial straightness of the inner hole from the center coordinates of all the inner hole sections; and fit the corresponding outer circle section center coordinates through the data detected by each outer circle section, and use the straightness evaluation criteria to obtain the initial straightness of the outer circle from the center coordinates of all the outer circle sections; Step 2: Establish the relationship between the inner hole straightness and the outer circle straightness through the inner hole section center coordinates and the outer circle section center coordinates: Cut the same section according to the initial straightness of the inner hole and the initial straightness of the outer circle, take this section and take the ideal axis of the inner hole as the origin (0,0) to establish a global rectangular coordinate system. In the establishment of the global rectangular coordinate system, set the auxiliary coordinate point (ΔX, ΔY), set R as the maximum value allowed for the inner hole straightness, and in this section, set the inner hole section center coordinate qualified inclusion area that meets the inner hole straightness as X. 2 +Y 2 ≤R 2 ; In this section, let the coordinates of the center of the inner hole section be (X1, Y1), let the coordinates of the center of the outer circle section be (X2, Y2), and let the auxiliary coordinates ΔX = X2-X1, ΔY = Y2-Y1, and the qualified inclusion area of ​​the center coordinates of the outer circle section that meets the inner hole straightness is (X-ΔX) 2 -(Y-ΔY) 2 ≤R 2 , convert the qualified inclusion area of ​​the inner hole section circle center coordinates that meet the inner hole straightness into the qualified inclusion area of ​​the outer circle section circle center coordinates that meet the inner hole straightness, and extend it to all sections and circle center coordinates, and thereby establish the relationship between the inner hole straightness and the outer circle straightness; Step 3: Calculate the correction angle range and distance range of the center coordinates of the outer circle section that meet the straightness of the inner hole: According to step 2, take the center coordinates (X2, Y2) of the outer circle section as the origin and the straight line passing through (ΔX, ΔY) and (X2, Y2) in the global coordinate system as the X-axis to establish a local coordinate system; When the coordinates of the center of the hole section in the global coordinate system (X1, Y1) are in the first and fourth quadrants in the global coordinate system, the coordinates of each point are converted in the local coordinate system: (X2, Y2) is converted to (O2, O2), (ΔX, ΔY) is converted to The equation of the qualified inclusion area of ​​the center coordinates of the outer circle section that meets the inner hole straightness is converted into In order to correct (O2, O2) to within the qualified inclusion area, the correction angle θ is: At this time, the correction range β is: When the coordinates of the center of the hole section in the global coordinate system (X1, Y1) are in the second and third quadrants in the global coordinate system, the coordinates of each point are converted in the local coordinate system: (X2, Y2) is converted to (02, 02), (ΔX, ΔY) is converted to The equation of the contained area of ​​the center coordinates of the outer circle section that meets the straightness of the inner hole is converted into In order to correct (02, 02) to the qualified inclusion area, the correction angle θ is: At this time, the correction range β is: In the local coordinate system, correct the length L of the tube parts: When the coordinates of the center of the hole section in the global coordinate system (X1, Y1) are in the first and fourth quadrants in the global coordinate system, the equation group is established: Or when the coordinates of the center of the hole section in the global coordinate system (X1, Y1) are in the second and third quadrants in the global coordinate system, establish the equation group: Solve the coordinates of the two intersection points, then the minimum corrected length is the distance from (02, 02) to the first intersection point, and the maximum corrected length is the distance from (02, 02) to the second intersection point. After the correction angle is selected, the correction range is between the minimum distance and the maximum distance. Repeat the above equations and apply them to all cross sections to fit a new outer circle straightness and a qualified inner hole straightness. Step 4, calibrate the pipe parts and judge whether the calibration is qualified: select the calibration angle by calculation and perform the calibration process on the pipe parts. After the calibration, fit the corresponding coordinates of the center of the outer circle section by detecting the outer circle section and evaluate the corrected outer circle straightness. Compare the corrected outer circle straightness with the new outer circle straightness in step 3. If the two are consistent, the calibration is qualified. Otherwise, repeat the calibration steps until the calibration is qualified and proceed to the next step. Step 5, verification: inspect the inner hole section of the qualified pipe parts, fit the corresponding inner hole section center coordinates and evaluate the corrected inner hole straightness, compare the corrected inner hole straightness with the qualified inner hole straightness in step 3, if the two are consistent, it is verified that the pipe parts are qualified, otherwise, return to step 4.

2. A method for straightening a pipe part according to claim 1, characterized in that: In step 1, the straightness evaluation criteria include the two-terminal point connection method, the least square method and the minimum area inclusion method.

3. A method for straightening a pipe part according to claim 1, characterized in that: In step 1, the device for detecting the initial straightness of the outer circle adopts a contact or non-contact detection device.

4. A method for straightening a pipe part according to claim 1, characterized in that: In step 1, the device for detecting the initial straightness of the inner hole adopts a contact or non-contact detection device.

5. A method for straightening a pipe part according to claim 1, characterized in that: In step one, the inner hole initial straightness detection and the outer circle initial straightness detection are performed synchronously or asynchronously.

6. A method for straightening a pipe part according to claim 1, characterized in that: In step 1, the data of each inner hole section detection is fitted with the corresponding inner hole section center coordinates using the least squares circle method, and the data of each outer circle section detection is fitted with the corresponding outer circle section center coordinates using the least squares circle method.

7. A method for straightening a pipe part according to claim 1, characterized in that: In step 2, the ideal axis of the inner hole is the least square center line of the ideal tube part.

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