Methods, tooling and assembly structures for measuring the roundness of large cylindrical or cylindrical structures

Abstract

This application discloses a method, tooling, and assembly structure for measuring the roundness of large cylindrical or cylindrical structures, belonging to the field of industrial measurement technology. The measurement method includes: fixing multiple measuring toolings at corresponding positions at both ends of the workpiece; and determining the theoretical initial value R of the workpiece radius extension. 延长 Determine the coordinates of the predetermined points, such that the actual distance from each predetermined point to the center of the workpiece end circle is R. 延长 The method involves setting measurement lines and measuring the actual distance between each measurement line and the outer surface of the workpiece. The roundness of the workpiece is determined by its actual outer diameter. The measuring fixture includes a connected fastening assembly and a positioning assembly, with the positioning assembly equipped with a reflective plate for positioning predetermined points. The measuring assembly structure includes multiple measuring fixtures located at both ends of the workpiece. The measurement lines corresponding to the same equally spaced positions at both ends of the workpiece are parallel. This application measures the roundness of the outer surface of a large cylinder from the outside, significantly reducing the operational difficulty of the measurement, achieving higher measurement accuracy, and simplifying the measurement of the roundness of large cylinders.

Description

Technical Field

[0001] This application belongs to the field of industrial measurement technology, and in particular relates to methods, tooling and assembly structures for measuring the roundness of large cylindrical or cylindrical structures. Background Technology

[0002] Structural deformation of cylinders or spheres refers to the bending or twisting of the structure itself or under external forces, resulting in deformation. This deformation can be expressed as roundness, which can be evaluated by initial deflection. Different measurement methods can be used for cylinders and spheres of different sizes or shapes. In the shipbuilding industry, roundness measurement of large cylindrical structures is particularly important. Large cylindrical structures refer to those that are too large to be machined in a single operation; these structures are generally assembled from multiple pieces. For the roundness of large cylindrical structures, the following three methods are commonly used:

[0003] 1. Pole strut method

[0004] The strut method is one of the earliest and most commonly used methods for assessing the initial deflection of large cylindrical structures. First, a center point (close to the theoretical center) must be located within the cylindrical structure, and a steel wire is stretched taut through this center. The distances from each equally spaced point on the shell plate to the measurement center are measured using struts. If the cylindrical structure is separated by internal walls or platforms, preventing measurement from a single center, measurements are taken from other points at predetermined distances from the rib measurement center, and the distances are calculated using a center-shifting algorithm. Then, using these values, the initial deflection at each equally spaced point is calculated using the "standard algorithm" (a simplified least squares method).

[0005] 2. Laser roundness measurement method

[0006] With the development of modern shipbuilding technology, laser ranging equipment such as laser theodolites, laser collimators, laser levels, and laser total stations have been introduced into the shipbuilding industry, making the application of laser measurement technology in the shipbuilding field increasingly widespread. A laser roundness measurement method for measuring the roundness of cylindrical bodies has been proposed. This method uses a total station to measure the three-dimensional coordinates of the points to be measured on the cylindrical body, obtaining a three-dimensional spatial point cloud. The point cloud is then fitted to a plane, and the three-dimensional point coordinates are projected onto the fitted spatial plane. These projected points are then used to fit a circle, and finally, the initial deflection of the measured point is obtained by comparing the projected points with the fitted circle.

[0007] 3. Sample method

[0008] Before using the template method to measure the roundness of the cylinder, it is necessary to mark the positions of 32 equally divided points on the cylinder. Finally, the radial roundness deviation of the shell is measured with the help of the pre-made template tooling, and the initial deflection is calculated by the initial deflection calculation formula of the 32 equally divided points.

[0009] However, due to their large size, large cylinders are difficult to measure. Existing measurement methods generally involve measuring from inside the cylinder. For cylinders with internal obstructions or structures, stress release and deformation occur due to the internal structure. Therefore, it is necessary to measure the roundness of the cylinder. However, existing methods cannot directly measure from inside the cylinder, or the measurement operation is difficult and prone to inaccurate results. Summary of the Invention

[0010] This application aims to at least partially solve the technical problem of roundness measurement of large cylindrical bodies with internal obstructions or structures. To this end, this application provides a method, tooling, and assembly structure for measuring the roundness of large cylindrical or cylindrical structures. By ignoring the space occupied by the internal structure of the large cylindrical body, the roundness of the outer surface of the large cylindrical body is measured from the outside, which significantly reduces the difficulty of measurement, has higher measurement accuracy, and makes it easier and more intuitive to measure the roundness of large cylindrical bodies. Large cylindrical bodies include large cylindrical structures and large cylindrical structures, both of which are applicable to this application.

[0011] In a first aspect, embodiments of this application provide a method for measuring the roundness of a large cylindrical or cylindrical structure, wherein the workpiece to be measured is a cylindrical or cylindrical structure, and the measurement method includes:

[0012] Fix multiple measuring fixtures at corresponding positions at both ends of the workpiece;

[0013] Determine the initial theoretical value R for workpiece radius extension. 延长 R 延长 =R+r, where R is the theoretical outer diameter from the center O of the workpiece end to its outer surface, and r is the theoretical distance from the predetermined point of the measuring fixture to the outer surface of the workpiece.

[0014] Determine the coordinates of the center O of the circle, and combine them with R. 延长 Determine the coordinates of predetermined points on the surface of the measuring fixture, such that the actual distance R′ from the predetermined point of each measuring fixture to the center O is R′ = R′. 延长 ;

[0015] A taut measuring line is set between predetermined points at both ends of the workpiece. At the section of the workpiece to be measured, the actual distance r between each measuring line and the outer surface of the workpiece is measured. i 'Take measurements;

[0016] Through R 延长 With r i The difference between ′ and ′ determines the actual outer diameter R of the workpiece at the same cross-section to be measured. 实 By comparing R with multiple R 实 The difference between them determines the roundness of the workpiece.

[0017] The actual outer diameter of the workpiece at the same measured section is determined by the difference between the theoretical initial value of the workpiece radius extension and the actual distance from each measuring line to the outer surface of the workpiece. The roundness of the workpiece is then determined by comparing the differences between the theoretical outer diameter and multiple actual outer diameters.

[0018] Compared to existing methods that measure from the inside of large cylinders, which are unsuitable for situations where the internal space is occupied by the cylinder and cannot measure the roundness of the cylinder from the outside, this application ignores the space occupied by the internal structure of the large cylinder, avoiding the influence of the internal structure on the measurement. It extends the radius of the workpiece by using a measuring fixture to facilitate external measurement of the roundness of the outer surface of the large cylinder. By determining the coordinates of predetermined points on the measuring fixture and constructing a standard theoretical radius, the unknown actual radius of the cylinder is transformed into the distance between the outer surface of the workpiece and the measuring line. The outer diameter from the center to the outer surface of the workpiece is obtained through direct measurement, thus achieving roundness measurement. This significantly reduces the operational difficulty of the measurement. Because it directly uses coordinate values ​​for calculation, it avoids the error caused by directly measuring the radius R when the size is large, only affecting the actual distance r. i The outer diameter of the workpiece can be obtained by measurement, with high measurement accuracy. It is also more convenient to measure the roundness of large cylinders, and the measurement is more intuitive, which has great advantages. At the same time, this measurement method can also be applied to the measurement of large cylindrical structures.

[0019] In an optional implementation, the measuring fixture is fixed, including:

[0020] Divide the workpiece into i equal parts along the circumference, where i is an integer ≥ 2;

[0021] Fix the measuring fixture at the corresponding equidistant positions at both ends of the workpiece.

[0022] In an optional implementation, when determining the coordinates of the center O and the predetermined point:

[0023] Using measuring tools, establish a rectangular coordinate system o-xyz with the workpiece's axial direction or the direction parallel to the axial direction as the x-axis; ensure that the x-values ​​of the coordinates of each predetermined point at both ends of the workpiece are equal;

[0024] Determine the coordinates of the center O of the circle;

[0025] First, attach reflective sheets to the surfaces of each measuring fixture. Adjust the position of the reflective sheets and measure the coordinates of the marked points on the reflective sheets using a measuring tool, ensuring that the marked points on the reflective sheets satisfy the following condition in the coordinate system o-xyz: the actual distance R′ from the marked point to the center O is R. 延长 The coordinates of the predetermined point are determined as the coordinates of the marker point.

[0026] In an alternative implementation, when considering the radius r of the measuring line... 测量线 At that time, through R 延长 With r i ′、r测量线 The difference is used to determine the actual outer diameter R of the workpiece at the same cross-section to be measured. 实 .

[0027] In optional implementations, the methods for setting the measuring lines include:

[0028] The predetermined points are used as the drilling points, and holes are drilled at the drilling points of each measuring fixture.

[0029] Measuring lines are passed through the corresponding points to be drilled and fixed to keep each measuring line straight. The number of measuring lines is i. The corresponding points to be drilled are located on the measuring fixtures at the corresponding positions at both ends of the workpiece.

[0030] In an optional implementation, determining the roundness of the workpiece includes:

[0031] By calculating R and R 实 The difference between them determines the roundness;

[0032] Or via R 实 The percentage deviation from R determines the roundness.

[0033] Secondly, embodiments of this application provide a roundness measuring fixture for a large cylindrical or cylindrical structure, which is applied to the aforementioned roundness measuring method. The measuring fixture includes:

[0034] Fastening components are used to fix the workpiece to the end. The fastening components can be adjusted to fix the position on the circumference of the workpiece end.

[0035] The positioning component is connected to the fastening component. The positioning component is equipped with a reflective sheet, which is used to locate the position of a predetermined point.

[0036] Using the above-mentioned measuring fixture, it is easy to fix the workpiece at the end, so that the position of the fastening component can be adjusted in the measurement method to meet the position setting requirements; the positioning component can provide a mounting base for the reflector, which facilitates the positioning of the measuring tool at the predetermined point. In this way, the measuring fixture serves as the basis for measuring large cylinders from the outside, providing a measurement reference point, and making it easier to measure the roundness of large cylinders.

[0037] In an optional implementation, the fastening assembly includes:

[0038] Fasteners, fasteners having slots, the slots are used to hold the end of the workpiece;

[0039] Locking components are fasteners that are connected to the workpiece.

[0040] In an optional implementation, the positioning component includes:

[0041] Positioning plate, the positioning plate is connected to the fastener, and the reflective sheet is attached to the surface of the positioning plate;

[0042] Reinforcing ribs connect the positioning plate and fasteners.

[0043] Thirdly, embodiments of this application provide a roundness measurement assembly structure for a large cylindrical or cylindrical structure, which employs the aforementioned roundness measurement fixture. The assembly structure includes:

[0044] Measuring fixtures and measuring lines are provided. Multiple measuring fixtures are placed at both ends of the workpiece, such that the multiple measuring fixtures are located at equally divided positions on the workpiece. The measuring lines corresponding to the same equally divided positions at both ends of the workpiece are parallel to each other, wherein the corresponding measuring lines are located between predetermined points of the measuring fixtures corresponding to the same equally divided positions at both ends of the workpiece.

[0045] By adopting the above-mentioned combined structure, multiple measuring fixtures can be combined into a whole system structure, providing measurement conditions for roundness measurement, facilitating measurement on the outer surface of the workpiece, and providing more outer diameter data by setting the equal positions of multiple measuring fixtures, reducing errors and improving the accuracy of measurement results. By transforming the measurement of the outer diameter of the workpiece into the measurement of the distance between the measuring line and the outer surface of the fixture, the measurement difficulty can be reduced, and the roundness measurement of any cross section to be measured can be realized.

[0046] As can be seen from the above technical solution, the beneficial effects of this application are as follows:

[0047] 1. This measurement method ignores the space occupied by the internal structure of large cylinders, avoiding the influence of the internal structure on the measurement. The workpiece radius is extended by using a measuring fixture to facilitate external measurement of the roundness of the outer surface of the large cylinder. By determining the coordinates of predetermined points on the measuring fixture, a standard theoretical radius is constructed. The unknown actual radius of the cylinder is transformed into the distance between the outer surface of the workpiece and the measuring line. The outer diameter from the center to the outer surface of the workpiece is obtained through direct measurement, thus achieving roundness measurement. This significantly reduces the operational difficulty of the measurement. Because coordinate values ​​are directly used for calculation, errors caused by directly measuring the radius R when the size is large are avoided; only the actual distance r is considered. i The outer diameter of the workpiece can be obtained by measurement, with high measurement accuracy. It is also more convenient to measure the roundness of large cylinders, and the measurement is more intuitive, which has great advantages. Large cylinders include large cylindrical structures and large cylindrical structures, both of which are applicable to this application.

[0048] 2. This measuring fixture can be easily fixed at the end of the workpiece, so that the position of the fastening components can be adjusted in the measurement method to meet the position setting requirements; through the positioning components, a mounting base for the reflector can be provided, which facilitates the positioning of the measuring tool at the predetermined point. In this way, the measuring fixture serves as the basis for measuring large cylinders from the outside, providing a measurement reference point, and making it easier to measure the roundness of large cylinders.

[0049] 3. This combined structure can integrate multiple measuring fixtures into a whole system structure, providing measurement conditions for roundness measurement, facilitating measurement on the outer surface of the workpiece. By setting the equal positions of multiple measuring fixtures, more outer diameter data can be provided, reducing errors and improving the accuracy of measurement results. By transforming the measurement of the outer diameter of the workpiece into the measurement of the distance between the measuring line and the outer surface of the fixture, the measurement difficulty can be reduced, and the roundness measurement of any cross section to be measured can be realized. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 The diagram illustrates the steps of an embodiment of a method for measuring the roundness of large cylindrical or cylindrical structures.

[0052] Figure 2 A schematic diagram illustrating an embodiment of a method for measuring the roundness of large cylindrical or cylindrical structures is shown.

[0053] Figure 3 An example of a method for measuring the roundness of a large cylindrical or cylindrical structure is shown in the front view.

[0054] Figure 4 An example of a method for measuring the roundness of a large cylindrical or cylindrical structure is shown in the front view.

[0055] Figure 5 A side view illustrating an embodiment of a method for measuring the roundness of a large cylindrical or cylindrical structure is shown.

[0056] Figure 6 A schematic diagram of an embodiment of a roundness measuring fixture for large cylindrical or cylindrical structures is shown.

[0057] Figure 7 A schematic diagram of an embodiment of a roundness measuring fixture for a large cylindrical or cylindrical structure with a reflective sheet is shown.

[0058] Figure 8A schematic diagram of an embodiment of a roundness measuring fixture for determining the drilling point of a large cylindrical or cylindrical structure is shown.

[0059] Figure 9 A side view schematic diagram of an embodiment of a roundness measuring fixture for a large cylindrical or cylindrical structure is shown.

[0060] Reference numerals: 100, measuring fixture; 110, fastening assembly; 111, fastener; 111a, slot; 112, locking element; 120, positioning assembly; 121, positioning plate; 121a, drilling point; 122, reinforcing rib; 123, reflector; 200, cylinder; 300, base; 400, measuring line. Detailed Implementation

[0061] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0062] It should be noted that all directional indications in the embodiments of the present invention are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0063] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0064] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0065] This application is described below with reference to the accompanying drawings and specific embodiments:

[0066] Please refer to Figure 1 The first aspect of this application provides a method for measuring the roundness of a large cylindrical or cylindrical structure. The workpiece to be measured is a cylindrical structure 200, such as a medium-sized cylindrical structure 200 with a radius of about 3m. The internal structure of the cylindrical structure 200 has reinforcing ribs 122 or reinforcing ribs, making it inconvenient to measure directly from inside the cylindrical structure 200. The workpiece is placed on a base 300, which is fixed to the ground and serves as the support foundation for the workpiece. To facilitate position adjustment, rollers are also provided at the bottom of the base 300. The measurement method includes:

[0067] S1. Fix multiple measuring fixtures 100 at corresponding positions at both ends of the workpiece. The number of measuring fixtures 100 can be set according to measurement needs, such as 32, 16 at each end of the workpiece. The measuring fixtures 100 adopt general-purpose clamps, which are commonly used clamps in production and processing, such as vises. Other structures can also be used, as long as they can be fixed to the edges at both ends of a large cylinder, such as suction cups. Taking a double-jaw suction cup as an example, the top of the double-jaw suction cup has a connecting rod. The two suction cups of the double-jaw suction cup are connected by the connecting rod. Determine the installation position of the measuring fixtures 100 on the outer side of both ends of the fixture, and fix the double-jaw suction cup in the designed installation position.

[0068] S2. Determine predetermined points on the surface of the measuring fixture 100, such that the actual distance R′ from the predetermined point of each measuring fixture 100 to the center O of the workpiece end is R′=R 延长 The predetermined point is determined on the connecting rod. This can be done by direct measurement using measuring tools such as tape measures, rangefinders, total stations, or other optical measuring instruments. The workpiece end refers to one or both ends of the cylinder 200. The center O of the workpiece end can be determined by repeated measurements using existing methods for finding the center. For example, the center can be found through the axis of symmetry. After determining the center O, a support is used to mark the center position with a physical object. Alternatively, a suspension method can be used to suspend a lead wire from the highest point of the workpiece end and fix a heavy ball at the bottom of the lead wire. The ball is used to mark the center position. Then, a measuring tool is used to determine a point on the connecting rod of each double-claw suction cup as the predetermined point, such that the actual distance from the predetermined point to the center is equal to R. 延长 .

[0069] Among them, R 延长 =R+r,R 延长The initial theoretical value for extending the workpiece radius is determined by extending the workpiece radius. R is the theoretical outer diameter from the center O of the workpiece end to the outer surface of the workpiece, i.e., the outer diameter of the workpiece end when the workpiece end is a perfect circle. r is the theoretical distance from the predetermined point of the measuring fixture 100 to the outer surface of the workpiece, which is the design value. The actual value of this value will vary depending on the position of the measuring fixture 100.

[0070] This step S2 can be broken down into two steps: first, determine the theoretical initial value R for extending the workpiece radius. 延长 Next, determine the coordinates of the predetermined point. When determining the coordinates of the predetermined point, first determine the coordinates of the center O of the circle as a reference to facilitate the positioning of the predetermined point, and then combine this with the coordinates of R. 延长 Use measuring tools to repeatedly determine a point on the surface of the measuring fixture 100, ensuring that the distance between this point and the center O remains constant at R. 延长 That is, find a point on the connecting rod mentioned above as the predetermined point, and the actual distance of the predetermined point from the center O is R′=R 延长 Always ensure that R′ remains unchanged.

[0071] S3. A taut measuring line 400 is set between predetermined points at both ends of the workpiece. The predetermined points refer to the points on the measuring fixture 100 at both ends of the workpiece. Thus, there are two predetermined points at both ends of the measuring fixture 100. The measuring line 400 is set between these two predetermined points, keeping it on a straight line between the two points. The measuring line 400 can pass directly through the two predetermined points, or an existing measuring frame can be erected and the line pulled so that the two predetermined points are on the extension of the measuring line 400. To ensure measurement accuracy, holes can be drilled at the predetermined points, and the two ends of the measuring line 400 can pass through these two predetermined points, keeping the measuring line 400 taut. After tautness, the measuring line 400 is fixed to the measuring fixture 100, or fixed to the measuring frame. The measuring line 400 uses existing measuring wires, such as steel wire or synthetic fiber. At the cross-section to be measured on the workpiece, the actual distance r between each measuring line 400 and the outer surface of the workpiece is measured. i The section to be measured refers to the section of the workpiece that needs to be measured. It is generally a section perpendicular to the axial direction of the cylinder 200. This section to be measured can be determined as the section where the internal obstruction or connecting structure of the workpiece is located. This is because when structures such as reinforcing ribs 122 and stiffening ribs are set inside the workpiece, it is easy to cause deformation of the workpiece. Therefore, the above-mentioned section can be measured.

[0072] S4, via R 延长 With r i The difference between ′ and ′ determines the actual outer diameter R of the workpiece at the same cross-section to be measured. 实 Let i represent the number of measuring fixtures 100 set at one end of the workpiece. The actual outer diameter of the workpiece at the same cross-section has i values, the number of which is determined by the number of measuring fixtures 100 set at one end of the workpiece. This allows for the measurement of R...实 Having i, R 实 The calculation is as follows:

[0073] R 实 =R 延长 -r i ′

[0074] Among them, R 实 R is the actual outer diameter of the workpiece. 延长 Let r be the initial theoretical value for extending the workpiece radius. i ′ represents the actual distance between each measuring line 400 and the outer surface of the workpiece, and i represents the number of the measuring line 400, which is also the number of the measuring fixture 100. This calculation method ignores the influence of the radius of the measuring line 400 on the measurement results. It is suitable for cases where the diameter of the measuring line 400 is small, such as 2mm. It is also suitable for cases where the workpiece is large and the size of the circular end of the workpiece differs greatly from the diameter of the measuring line 400.

[0075] By comparing R with multiple R 实 The difference between the two is used to determine the roundness of the workpiece. The roundness of the workpiece is determined using the existing calculation method, that is, based on the known outer diameter R of the workpiece. 实 By substituting the theoretical outer diameter R of the workpiece into existing calculation formulas or relevant formulas representing roundness, the roundness of the workpiece can be determined. For example, using: (R) 实max -R 实min ) / R 实max Roundness can also be calculated using other formulas for evaluating roundness.

[0076] In an optional embodiment, the workpiece to be measured is a cylindrical structure, such as a cylinder with a radius of about 3m, and the measuring fixture 100 is fixed on the outer periphery of the end of the cylinder, or a large cylindrical structure, such as a cylinder 200 with a radius of about 5m, and similarly, the measuring fixture 100 is fixed on the end of the cylinder 200.

[0077] This application ignores the space occupied by the internal structure of the large cylinder, avoiding the influence of the internal structure on the measurement. The radius of the workpiece is extended by the measuring fixture 100 to facilitate external measurement of the roundness of the outer surface of the large cylinder. By determining the coordinates of predetermined points on the measuring fixture 100, a standard theoretical radius is constructed. The unknown actual radius of the cylinder 200 is converted into the distance between the outer surface of the workpiece and the measuring line 400. The outer diameter from the center to the outer surface of the workpiece is obtained through direct measurement, thus achieving roundness measurement. This significantly reduces the operational difficulty of the measurement. Because the coordinate values ​​are directly used for calculation, errors caused by directly measuring the radius R when the size is large are avoided; only the actual distance r is considered. iThe outer diameter of the workpiece can be obtained by measurement, with high measurement accuracy. It is also more convenient to measure the roundness of large cylinders, and the measurement is more intuitive, which has great advantages. Large cylinders include large cylindrical structures and large cylindrical structures, both of which are applicable to this application.

[0078] In an optional embodiment, fixing the measuring fixture 100 in S1 includes:

[0079] Divide the workpiece into i equal parts along the circumference, where i is an integer greater than or equal to 2; along the axial direction parallel to the workpiece, divide the workpiece into equal parts around its circumference, such as 8, 20, 24, 32, 36, etc., as long as i is an integer. By setting the division, as much measurement data as possible can be provided, and the data can be distributed as widely as possible throughout the cylinder 200, thus enabling a more comprehensive and accurate measurement of the workpiece's roundness.

[0080] Fix the measuring fixture 100 at the corresponding equidistant positions at both ends of the workpiece. The equidistant points can be marked at both ends of the workpiece. Fix the measuring fixture 100 at the equidistant points and check whether the fixed positions of the measuring fixture 100 at both ends of the workpiece are aligned. If there is obvious misalignment, adjust it into place. The opposite positions of the two ends of the workpiece at the same equidistant position are the corresponding positions of the two ends of the workpiece. The above fixing method can be clamping, screw fixing or other fixing methods.

[0081] In an optional implementation, when determining the coordinates of the center O and the predetermined point in S2:

[0082] Using a measuring tool, a rectangular coordinate system o-xyz is established with the workpiece's axial direction or the direction parallel to the axial direction as the x-axis. This coordinate system is a virtual coordinate system, a three-dimensional coordinate system set in the measuring tool. The x-values ​​of the coordinates of each predetermined point at both ends of the workpiece are made equal. At the same end of the workpiece, all predetermined points of the measuring fixture 100 are located on the same vertical plane, and this plane is perpendicular to the x-axis. In this way, the x-axis coordinates of each predetermined point at the end of the workpiece are equal. The measurement of three-axis coordinates is transformed into the measurement of two axes, which reduces the measurement difficulty, simplifies the calculation, and improves the accuracy of measurement and calculation.

[0083] Determine the coordinates of the center O. The existing method for determining the coordinates of the center O can be direct measurement, or the end circle of the cylinder 200 can be simulated in the measuring tool, and then multiple points at the end of the cylinder 200 are measured in the coordinate system. The coordinates of the center O are then determined using the built-in fitting function of the measuring tool. When determining the coordinates of the predetermined points, reflective sheets 123 are first attached to the surface of each measuring fixture 100, with the reflective surface of the reflective sheet 123 facing the measuring tool. This setting of the reflective sheet 123 is used in conventional measurement methods. The surface of the reflective sheet 123 is marked with crosses or other symbols for easy measurement and observation. Keep the reflective sheet 123 attached to the measuring fixture 100 and adjust its position. During adjustment, the coordinates of the marked points of the reflective sheet 123 are measured using the measuring tool. The actual distance from the marked points of the reflective sheet 123 to the center O is fitted and calculated using the built-in calculation software of the measuring tool, ensuring that the actual distance R′ from the marked points of the reflective sheet 123 to the center O in the coordinate system o-xyz satisfies: 延长 The coordinates of the predetermined point are then used as the coordinates of the marker point. Using the aforementioned measuring tool to determine the coordinates allows for a faster and more accurate determination of the predetermined point coordinates, significantly improving measurement efficiency, especially when the workpiece is large.

[0084] In an alternative implementation, in S4, when considering the radius r of the measuring line 400... 测量线 At this time, firstly, to obtain more accurate measurement values, and secondly, because the diameter of the measuring line 400 affects the measurement, the radius of the measuring line 400 needs to be included in the calculation, through R. 延长 With r i ′、r 测量线 The difference is used to determine the actual outer diameter R of the workpiece at the same cross-section to be measured. 实 There are i measurement lines 400 at the same cross-section to be measured. Measurements are performed on each measurement line 400 to obtain the outer diameter data of i points on the outer surface of the workpiece. The specific calculation formula is as follows:

[0085] R 实 =R 延长 -r i ′-r 测量线

[0086] Among them, R 实 R is the actual outer diameter of the workpiece. 延长 Let r be the initial theoretical value for extending the workpiece radius. i ′ represents the actual distance of each measuring line 400 from the outer surface of the workpiece, i is the number of the measuring line 400, which is also the number of the measuring fixture 100, and r 测量线 The radius of the measuring line is 400.

[0087] In an optional implementation, the measurement line 400 is set in S3 in the following ways:

[0088] The predetermined point is designated as the point to be drilled 121a. After the coordinates of the predetermined point are determined, the point to be drilled 121a is marked on the surface of the measuring fixture 100 by marking. Drilling is performed at the point to be drilled 121a of each measuring fixture 100. A hole penetrating the measuring fixture 100 is constructed at the position of the point to be drilled 121a. The point to be drilled 121a can be marked by a punch. If the punch applies a large force, a small hole can be directly drilled on the measuring fixture 100 as a hole, which also saves the drilling step.

[0089] Measuring lines 400 are passed through and fixed to the corresponding points to be drilled 121a. For example, a steel wire can be used to pass through the corresponding points to be drilled 121a and its ends can be spot-welded to the corresponding measuring fixtures 100 at both ends of the workpiece. Other fixing methods can also be used to fix the steel wire to the measuring fixtures 100, ensuring that each measuring line 400 remains taut. The number of measuring lines 400 is i. The corresponding points to be drilled 121a are located on the measuring fixtures 100 at the corresponding positions at both ends of the workpiece. This method of setting up the measuring lines 400 allows them to pass directly through predetermined points, ensuring that the distance between each point on the measuring line 400 and the corresponding center point on the workpiece axis remains constant at R. 延长 Using the measuring line 400 as a reference line facilitates the measurement of the outer diameter of the workpiece.

[0090] In an optional implementation, determining the roundness of the workpiece in step S4 includes:

[0091] By calculating R and R 实 The difference between the measured radius and the theoretical radius determines the roundness. Roundness can be calculated using existing methods. These methods require the following parameters: the difference between the measured radius and the theoretical radius, i.e., the theoretical outer diameter R from the center O of the workpiece end to the outer surface of the workpiece, and the actual outer diameter R of the workpiece. 实 The difference between them can also be expressed using the concept of deflection. Here, the deflection of the workpiece refers to the amount of deformation generated by the workpiece's own structure. The calculation is based on the difference. The above calculation process is the existing method and is omitted here.

[0092] In an optional implementation, determining the roundness of the workpiece in step S4 further includes:

[0093] Through R 实 The percentage deviation from radius R is used to determine roundness. This calculation method is also part of the existing calculation method. In the existing calculation method, the parameters that need to be known include the actual outer diameter R. 实 The degree of deviation from the theoretical outer diameter R from the center O to the outer surface of the workpiece; the roundness of the workpiece can be evaluated using the percentage of the above deviation. For example, when the above deviation is defined as ≤0.2%, the roundness of the workpiece meets the processing requirements. In an optional embodiment, the roundness of the workpiece can also be evaluated by the number of deviations. For example, when the workpiece is divided into i equal parts, the measured R... 实There are i values ​​in total. A deviation percentage is defined, and R values ​​that meet this percentage will be... 实 The number of items is used to define and evaluate roundness.

[0094] A second aspect of this application provides a roundness measuring fixture for a large cylindrical or cylindrical structure, which is applied to the roundness measuring method described above. The measuring fixture 100 includes a fastening component 110 and a positioning component 120. The fastening component 110 is used to fix the end of the workpiece to be measured. The fastening component 110 adopts a conventional parts clamp, similar to a clip structure. The fastening component 110 can clamp the edges at both ends of the workpiece. This fastening component 110 is for the case where the workpiece is a cylinder 200. The fastening component 110 can be adjusted and fixed on the circumference of the end of the workpiece. The positioning component 120 is connected to the fastening component 110. The positioning component 120 adopts a plate structure. In other embodiments, it can also adopt a block, rod, or other structure. The positioning component 120 is fixed to the fastening component 110 by welding, or it can be made into an integral structure. The positioning component 120 is provided with a reflective sheet 123. The reflective sheet 123 is used to position a predetermined point. The reflective sheet 123 is attached to the surface of the positioning component 120 by adhesive, which facilitates the adjustment and fixation of the reflective sheet 123. Using the above-mentioned measuring fixture 100, it is easy to fix the workpiece end, so that the position of the fastening component 110 can be adjusted in the measurement method to meet the position setting requirements; the positioning component 120 can provide the mounting base for the reflector 123, which facilitates the positioning of the measuring tool at the predetermined point. In this way, the measuring fixture 100 serves as the basis for measuring large cylinders from the outside, providing a measurement reference point, and making it easier to measure the roundness of large cylinders.

[0095] In an optional embodiment, the fastening assembly 110 includes a fastener 111 and a locking member 112. The fastener 111 has a slot 111a for engaging with the end of the workpiece. The shape of the slot 111a matches the shape of the edges at both ends of the cylinder 200, or one side of the slot 111a matches the outer edge of the cylinder 200, so that the inner side of the fastener 111 formed by the slot 111a can fit tightly against the outer periphery of the end of the cylinder 200. The fastener 111 also has a locking hole, which connects to the outer side of the fastener 111. Within the slot 111a, the locking hole is used to connect the locking element 112. The locking element 112 can be a screw, a snap-fit ​​structure, or other locking structures. The locking element 112 is connected to the fastener 111 through the locking hole. The fastener 111 is locked to the end of the cylinder 200 through the slot 111a, and the inner side of the fastener 111 is in close contact with the outer surface of the end of the cylinder 200. At this time, the locking hole is located inside the cylinder 200. The locking element 112 is tightened inside the cylinder 200, and the fastener 111 is fixed to the end of the workpiece through the locking element 112.

[0096] In an optional embodiment, the positioning component 120 includes a positioning plate 121 and a reinforcing rib 122. The positioning plate 121 is a plate structure and can be a triangular plate. In other embodiments, it can also be a quadrilateral, circular, or other regular-shaped plate. One side of the positioning plate 121 is vertically connected to the outside of the fastener 111. When the fastener 111 is installed at the end of the workpiece, the locking member 112 and the positioning plate 121 are located on the inner and outer sides of the cylinder 200, respectively. The connection between the positioning plate 121 and the fastener 111 can be fixed by welding or integral molding. The reflective sheet 123 is attached to the surface of the positioning plate 121. The reinforcing rib 122 is for reinforcing the measurement. The overall strength structure of the measuring tool 100 includes a reinforcing rib 122 made of a triangular plate, or other structural forms. One side of the reinforcing rib 122 is connected to the positioning plate 121, and the other side of the reinforcing rib 122 is connected to the fastener 111. After connection, the reinforcing rib 122 is vertically fixed in the middle of the positioning plate 121. This position of the reinforcing rib 122 can be used for positioning of a predetermined point. In this way, the point to be drilled 121a and the reinforcing rib 122 are on the same line, which makes it easy to determine the predetermined point. The connection between the reinforcing rib 122 and the positioning plate 121 can be by welding, or other connection methods, or the reinforcing rib 122 and the positioning plate 121 can be integrally formed.

[0097] A third aspect of this application provides a roundness measurement assembly structure for a large cylindrical or cylindrical structure. This assembly structure employs the aforementioned roundness measuring fixture 100. The assembly structure includes multiple measuring fixtures 100 and measuring lines 400. The number of measuring fixtures 100 is determined by the number of equal divisions of the workpiece, and this number = 2i. The measuring lines 400 are made of steel wire, but can also be made of other materials, such as synthetic fibers. The multiple measuring fixtures 100 are located at both ends of the workpiece. The fixing method of the measuring fixtures 100 at the ends of the workpiece is as described in the above embodiment, ensuring that the multiple measuring fixtures 100 are positioned at the equal divisions of the workpiece. At the same equidistant position at both ends of the cylindrical body, a measuring fixture 100 is set to form two corresponding measuring fixtures 100. The line connecting the holes on the corresponding measuring fixtures 100 is parallel to the axis of the workpiece, which facilitates the positioning of the measuring line 400. The measuring lines 400 at the same equidistant position at both ends of the workpiece are parallel to each other. That is, the measuring lines 400 connected to all the measuring fixtures 100 set on the workpiece are parallel to each other and parallel to the axis of the workpiece. The corresponding measuring lines 400 are located between predetermined points of the measuring fixtures 100 at the same equidistant position at both ends of the workpiece. The setting method is the same as the measuring fixtures 100 in the above embodiment.

[0098] By adopting the above-mentioned combined structure, multiple measuring fixtures 100 can be combined into a whole system structure, providing measurement conditions for roundness measurement, facilitating measurement on the outer surface of the workpiece. By setting the equal positions of multiple measuring fixtures 100, more outer diameter data can be provided, reducing errors and improving the accuracy of measurement results. By transforming the measurement of the outer diameter of the workpiece into the measurement of the distance between the measuring line 400 and the outer surface of the fixture, the measurement difficulty can be reduced, and the roundness measurement of any cross section to be measured can be realized.

[0099] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," "optional example," or "optional implementation," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0100] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0101] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for measuring the roundness of a large cylindrical or cylindrical structure, wherein the workpiece to be measured is a cylindrical or cylindrical structure, characterized in that, include: Multiple measuring fixtures (100) are fixed at corresponding positions at both ends of the workpiece; Determine the initial theoretical value for workpiece radius extension R 延长 , R 延长 = R + r , R Let O be the theoretical outer diameter from the center O of the workpiece end to its outer surface. r The theoretical distance from the predetermined point of the measuring fixture (100) to the outer surface of the workpiece; Determine the coordinates of the center O of the circle, and combine them with... R 延长 The coordinates of predetermined points are determined on the surface of the measuring fixture (100), such that the actual distance between the predetermined points of each measuring fixture (100) and the center O is determined. R ′= R 延长 ; A taut measuring line (400) is set between predetermined points at both ends of the workpiece. At the section of the workpiece to be measured, the actual distance between each measuring line (400) and the outer surface of the workpiece is measured. r i 'Take measurements; pass R 延长 and r i The difference between the two values ​​determines the actual outer diameter of the workpiece at the same cross-section. R 实 By comparison R With multiple R 实 The differences between them determine the roundness of the workpiece; When the measuring fixture (100) is fixed, it includes: Workpiece along the circumference i equal parts, i It is an integer ≥ 2; Fix the measuring fixture (100) at the corresponding equal division positions at both ends of the workpiece; When determining the coordinates of the center O and the predetermined point: Using measuring tools, the workpiece's axial direction or direction parallel to the axial direction is taken as the reference. x Establish a rectangular coordinate system based on the axes. o-xyz ; to make the coordinates of each predetermined point at both ends of the workpiece x The values ​​are equal; Determine the coordinates of the center O of the circle; First, attach reflective sheets (123) to the surface of each measuring fixture (100), adjust the position of the reflective sheets (123), and measure the coordinates of the marked points on the reflective sheets (123) using measuring tools, so that the marked points on the reflective sheets (123) are aligned in the coordinate system. o-xyz The condition is satisfied that: the actual distance from the marker point to the center O of the circle is satisfied. R ′= R 延长 The coordinates of the predetermined point are determined as the coordinates of the marker point; The methods for setting the measuring line (400) include: The predetermined point is used as the drilling point, and drilling is performed at the drilling point of each measuring fixture (100); Measuring wires (400) are passed through the corresponding holes to be drilled and fixed in place, keeping each measuring wire (400) taut. The number of measuring wires (400) = i The corresponding punching points are located on the measuring fixtures (100) at the corresponding positions at both ends of the workpiece.

2. The method for measuring the roundness of a large cylindrical or cylindrical structure according to claim 1, characterized in that, When considering the radius of the measuring line (400) r 测量线 At that time, through R 延长 and r i ′、 r 测量线 The difference is used to determine the actual outer diameter of the workpiece at the same cross-section to be measured. R 实 .

3. The method for measuring the roundness of a large cylindrical or cylindrical structure according to claim 1, characterized in that, Determining the roundness of a workpiece includes: Through calculation R and R 实 The difference between them determines the roundness; Or through R 实 Deviation R The percentage is used to determine the roundness.

4. A roundness measuring fixture for a large cylindrical or cylindrical structure, characterized in that, The roundness measurement method according to any one of claims 1-3, wherein the measuring fixture comprises: A fastening assembly (110) is used to fix the workpiece to be tested at the end, and the fastening assembly (110) can be adjusted to fix the position on the circumference of the end of the workpiece. A positioning component (120) is connected to the fastening component (110). The positioning component (120) is provided with a reflective sheet (123) for positioning the position of the predetermined point.

5. The roundness measuring fixture for large cylindrical or cylindrical structures according to claim 4, characterized in that, The fastening assembly (110) includes: Fastener (111), the fastener (111) is provided with a slot (111a), the slot (111a) is used to lock into the end of the workpiece; A locking element (112) is connected to the fastener (111), and the fastener (111) is fixed to the workpiece by the locking element (112).

6. The roundness measuring fixture for large cylindrical or cylindrical structures according to claim 5, characterized in that, The positioning component (120) includes: A positioning plate (121) is connected to the fastener (111), and a reflective sheet (123) is attached to the surface of the positioning plate (121). A reinforcing rib (122) connects the positioning plate (121) and the fastener (111).

7. A roundness measurement assembly structure for a large cylindrical or cylindrical structure, characterized in that, The roundness measuring fixture according to any one of claims 4-6, wherein the combined structure comprises: The measuring fixture (100) and measuring line (400) are provided at both ends of the workpiece, such that the measuring fixture (100) is located at the same division position of the workpiece; the measuring lines (400) corresponding to the same division position at both ends of the workpiece are parallel, wherein the corresponding measuring lines (400) are located between predetermined points of the measuring fixture (100) corresponding to the same division position at both ends of the workpiece.

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