A lofting and unfolding method for a tapered barrel structure
By using the perpendicular line and projection line of the cylinder centerline to determine the minor and major axes in the inclined cylinder structure, and combining this with the method of equally dividing the projection points, the complexity and accuracy problems of the inclined cylinder layout and development were solved, achieving efficient and accurate layout and development, and reducing production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CSSC HUANGPU WENCHONG SHIPBUILDING CO LTD
- Filing Date
- 2023-10-31
- Publication Date
- 2026-06-30
AI Technical Summary
The layout and unfolding process of the inclined cylinder is complex, lacks precision, is prone to errors, and increases production costs.
By creating the side view and normal section view of the cylinder, the minor axis and major axis of the inclined plane are determined using the perpendicular line and projection line of the cylinder's centerline. Combined with the unfolding method of equally divided projection points, the layout and unfolding process of the inclined cylinder is simplified.
It improves the accuracy and efficiency of layout and development of the inclined cylinder structure, simplifies the layout process, facilitates cylinder installation, and reduces production costs.
Smart Images
Figure CN117485508B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of shipbuilding technology, and in particular to a method for laying out and developing a sloping cylindrical structure. Background Technology
[0002] Ship structures are intricately interwoven, with some structures requiring an inclined distribution. When cylindrical structures are affected by the arrangement of related inclined structures, they will form slanted openings. Laying out and developing slanted cylindrical openings is quite difficult and requires high precision. The cylindrical openings must perfectly match the related connecting structures; otherwise, the cylindrical structure may be rendered unusable.
[0003] The previous layout and unfolding process was complicated, lacked versatility, was not accurate, and was prone to errors. Therefore, when laying out and unfolding, the unfolded parts often needed to be given extra allowance, and then trimmed into place during installation. This increased the difficulty of cylinder assembly, reduced work efficiency, and increased production costs. Summary of the Invention
[0004] The purpose of this invention is to provide a method for laying out and developing a slanted cylindrical structure, so as to effectively improve the accuracy and efficiency of laying out and developing the slanted cylindrical structure.
[0005] To achieve the above objectives, the present invention provides a method for laying out and developing a slanted cylindrical structure, comprising the following steps:
[0006] S1. Create the side view and normal section view of the cylinder. The center O of the cylinder in the side view and the center O1 of the cylinder in the normal section view are both located on the center line of the cylinder in the side view.
[0007] S2, in the side view, draw a perpendicular line from the center O of the cylinder to the center line of the cylinder. The perpendicular line intersects the outline of the inclined opening of the cylinder at points H and V. Connect points H and V to obtain line segment HV. Line segment HV is the minor axis projection line of the inclined plane.
[0008] S3, Project line segment HV along the center line of the cylinder onto the normal section diagram to obtain the short axis section projection line H1V1 on the normal section diagram, and obtain the long axis section projection line P1W1 perpendicular to the short axis section projection line on the normal section diagram;
[0009] S4. Project the long axis section projection line P1W1 along the center line of the cylinder to the side view to obtain the line segment PW that intersects with the contour line of the inclined opening. The line segment PW is the long axis projection line of the inclined opening plane.
[0010] S5. Draw a perpendicular line from point P to the center line of the cylinder and intersect the extension of the cylinder outline at point Q. Draw a perpendicular line from point W to the center line of the cylinder and intersect the cylinder outline at point T. Connect point Q and point T to obtain line segment QT.
[0011] S6. Divide the cylinder outline of the normal section view into several equal division points. Project each division point along the cylinder centerline onto line segment QT to obtain the corresponding equal division projection point. The projection point of point Q along the cylinder centerline on the normal section view is the first reference point. Draw the first reference line parallel to the cylinder centerline. The projection point of point Q on the first reference line is the second reference point.
[0012] S7. Select an equally divided projection point to make a second reference line perpendicular to the first reference line. The intersection of the second reference line and the first reference line is the center projection point. Measure the arc length of the arc between the equally divided point and the first reference point. With the center projection point as one end, cut a projection line segment of the same length as the arc length on the second reference line to obtain the unfolded point of the equally divided projection point.
[0013] S8. Repeat step S7 to obtain the development points of each equally divided projection point. Then, smoothly connect the second reference point to each development point to obtain the development line of the bevel contour line.
[0014] S9. Draw parallel lines parallel to the first baseline through both ends of the development line. Draw the outline segment of the shortest generatrix of the inclined cylinder on the parallel lines. The endpoint of the outline segment is the generatrix development point. Connect the two generatrix development points to complete the layout development diagram of the inclined cylinder.
[0015] Preferably, in step S3, the centerline of the cylinder in the side view intersects the normal section view at points X and Y, and the normal line passing through the center O1 and perpendicular to the centerline of the cylinder intersects the normal section view at points M1 and N1. Points X, Y, M1, and N1 are four quadrant points.
[0016] Project points H and V along the center line of the cylinder in the side view to the normal section view to obtain the projection point H1 corresponding to point H and the projection point V1 corresponding to point V. Point H1 is in the first quadrant and point V1 is in the third quadrant. Determine ∠XO1H1 as Z degrees. Rotate the straight line M1N1 counterclockwise by Z degrees with O1 as the center to obtain the projection line P1W1 of the major axis section.
[0017] Preferably, in step S4, points P1 and W1 are projected onto the side view along the center line of the cylinder to obtain points P and W, and points P and W are connected to obtain the major axis projection line PW passing through the center O.
[0018] Preferably, in step S6, when dividing the cylinder outline of the normal section view into equal parts, the first reference point is one of the division points.
[0019] Preferably, in step S6, there are a total of sixteen division points.
[0020] Preferably, in step S7, among the equidistant points, the arc between the two equidistant points on both sides of the first reference point is twice the arc length, and two unfolding points are obtained synchronously with the central projection point as the center.
[0021] Preferably, in step S9, the first length L1 of the first generatrix passing through point Q is measured on the cylinder outline, and a reference line segment of the first length L1 is cut off on the first reference line with the second reference point as the endpoint. The endpoint of the reference line segment is the first unfolding point. The second length L2 of the second generatrix passing through point T is measured on the cylinder outline, and the length of the outline segment is L2. The generatrix unfolding point and the first unfolding point are connected to complete the layout unfolding diagram of the oblique cylinder.
[0022] Compared with existing technologies, the layout and unfolding method of the inclined cylindrical structure of this invention has the following advantages: the inclined plane of the inclined cylindrical structure is an elliptical surface, and the minor axis of the elliptical surface is necessarily the diameter of the cylindrical structure and perpendicular to the center line of the cylindrical structure. By drawing a perpendicular line to the center line of the cylindrical structure, the minor axis projection line is obtained. The minor axis and the major axis of the elliptical surface are necessarily perpendicular to each other on the normal section, thus obtaining the major axis section projection line and the major axis projection line. Using the major axis projection line as a reference, the actual size line segment QT of the major axis is obtained. The inclined plane is unfolded by equally dividing the arc length of the contour of the inclined plane, and finally the layout and unfolding of the cylindrical structure is realized. This simplifies the unfolding method of the inclined cylindrical structure, and the unfolding method is simple and reliable. It realizes the accurate layout and unfolding of any inclined cylindrical structure, facilitates the installation of the cylindrical structure, and saves production costs. Attached Figure Description
[0023] Figure 1 These are the side view a) and normal section view b) of the inclined cylinder structure of the present invention, which are the layout and unfolding method of the inclined cylinder structure.
[0024] Figure 2 This is a schematic diagram illustrating the process of determining the major and minor axes in the layout and unfolding method of the oblique-mouth cylindrical structure of the present invention.
[0025] Figure 3 This is a schematic diagram of the equal division unfolding process of the layout unfolding method for the oblique-mouth cylindrical structure of the present invention;
[0026] Figure 4 This is a layout diagram of the oblique-mouthed cylindrical structure after it has been developed, according to the layout and development method of the oblique-mouthed cylindrical structure of the present invention. Detailed Implementation
[0027] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.
[0028] A preferred embodiment of the layout and development method for an oblique-mouth cylindrical structure of the present invention is as follows: Figures 1 to 4 As shown, the layout and development method of this inclined cylindrical structure includes the following steps:
[0029] S1. Create the side view and normal section view of the cylinder. The center O of the cylinder in the side view and the center O1 of the cylinder in the normal section view are both located on the center line of the cylinder in the side view.
[0030] S2, in the side view, draw a perpendicular line from the center O of the cylinder to the center line of the cylinder. The perpendicular line intersects the outline of the inclined opening of the cylinder at points H and V. Connect points H and V to obtain line segment HV. Line segment HV is the minor axis projection line of the inclined plane.
[0031] S3, Project line segment HV along the center line of the cylinder onto the normal section diagram to obtain the short axis section projection line H1V1 on the normal section diagram, and obtain the long axis section projection line P1W1 perpendicular to the short axis section projection line on the normal section diagram;
[0032] S4. Project the long axis section projection line P1W1 along the center line of the cylinder to the side view to obtain the line segment PW that intersects with the contour line of the inclined opening. The line segment PW is the long axis projection line of the inclined opening plane.
[0033] S5. Draw a perpendicular line from point P to the center line of the cylinder and intersect the extension of the cylinder outline at point Q. Draw a perpendicular line from point W to the center line of the cylinder and intersect the cylinder outline at point T. Connect point Q and point T to obtain line segment QT.
[0034] S6. Divide the cylinder outline of the normal section view into several equal division points. Project each division point along the cylinder centerline onto line segment QT to obtain the corresponding equal division projection point. The projection point of point Q along the cylinder centerline on the normal section view is the first reference point. Draw the first reference line parallel to the cylinder centerline. The projection point of point Q on the first reference line is the second reference point.
[0035] S7. Select an equally divided projection point to make a second reference line perpendicular to the first reference line. The intersection of the second reference line and the first reference line is the center projection point. Measure the arc length of the arc between the equally divided point and the first reference point. With the center projection point as one end, cut a projection line segment of the same length as the arc length on the second reference line to obtain the unfolded point of the equally divided projection point.
[0036] S8. Repeat step S7 to obtain the development points of each equally divided projection point. Then, smoothly connect the second reference point to each development point to obtain the development line of the bevel contour line.
[0037] S9. Draw parallel lines parallel to the first baseline through both ends of the development line. Draw the outline segment of the shortest generatrix of the inclined cylinder on the parallel lines. The endpoint of the outline segment is the generatrix development point. Connect the two generatrix development points to complete the layout development diagram of the inclined cylinder.
[0038] like Figure 1As shown, in step S1, the side view of the cylinder is a view along the diameter direction of the cylinder, and the normal section view is a view perpendicular to the center line of the cylinder. At this time, the inclined plane of the cylinder in the side view is elliptical, and the major and minor axes of the ellipse are unknown. The outline of the cylinder in the normal section view is circular, and the radius of the cylinder is R. When unfolding the inclined cylinder, it is necessary to obtain the major and minor axes of the inclined plane. The center O of the cylinder in the side view and the center ○1 of the cylinder in the normal section view are both located on the center line of the cylinder in the side view, which meets the requirements of mechanical drawing and facilitates subsequent projection needs.
[0039] In step S2, the inclined plane of the inclined cylinder is an elliptical surface. The minor axis of the elliptical surface must be the diameter of the cylinder and perpendicular to the center line of the inclined cylinder. By drawing a perpendicular line to the center line of the cylinder, the intersection of the perpendicular line and the outline of the inclined plane is the two ends of the minor axis, thus obtaining the minor axis projection line HV.
[0040] In step S3, since the oblique plane is an ellipse, the projections of its major and minor axes onto the normal section diagram must be perpendicular to each other. Projecting the minor axis projection line HV onto the normal section diagram yields the minor axis section projection line H1V1. Then, utilizing the perpendicular relationship between the minor and major axis section projection lines, the major axis section projection line P1W1 can be obtained. Using the relationship between the minor and major axes to obtain the major axis section projection line simplifies the acquisition of the major axis section projection line, facilitating its acquisition in step S4.
[0041] In step S4, the projection of the major axis section P1W1 along the center line of the cylinder intersects the oblique opening contour line at the endpoint of the major axis, thus obtaining the major axis projection line PW. The major axis projection line PW passes through the center O of the cylinder.
[0042] In step S5, when the inclined cylinder rotates around the center line of the cylinder, the movement trajectories of the two endpoints P and W of the major axis of the inclined plane are circular. This circle is perpendicular to the center line of the cylinder. Therefore, line segment QT is equivalent to the maximum size of the projection of the major axis of the inclined plane around the center line of the cylinder in the side view. That is, the length of line segment QT is the actual size of the major axis of the ellipse of the inclined plane. When the inclined cylinder rotates to this position, the elliptical surface of the inclined plane is completely projected onto line segment QT, and the entire minor axis is projected onto the center O. The length of the minor axis is the diameter of the cylinder structure.
[0043] In steps S6 and S7, the cylinder outline of the normal section view is divided into equal parts. During unfolding, the arc distance between the division points is the radial distance between adjacent unfolded points of the oblique plane outline after unfolding, and the distance between the equally divided projection points along the cylinder centerline is the axial distance between adjacent unfolded points of the oblique plane outline after unfolding, thus obtaining each unfolded point. The more equal parts, the higher the accuracy of the unfolded outline.
[0044] In step S7, since point Q is the endpoint of the major axis, the second reference point is the center projection point of point Q, which is also the unfolded point of point Q, and the first reference line is the projection line of the center line of the inclined cylinder.
[0045] In step S9, after the oblique opening contour line of the oblique opening cylinder is unfolded, the unfolded line of the generatrix is a plane. The unfolded shape of the cylinder at the end away from the oblique opening is a straight line. The length of the shortest generatrix is the length of the plate at the two ends of the unfolded line after the oblique opening cylinder is unfolded, which is also the length of the contour line segment. The unfolded point of the generatrix after the shortest generatrix is unfolded coincides with the end of the contour line segment. The connection of the unfolded points of the generatrix is the layout unfolded diagram of the oblique opening cylinder.
[0046] The method for laying out and unfolding the inclined cylinder structure uses the projection line of the major axis as a reference to obtain the actual size line segment QT of the major axis. The inclined plane is unfolded by dividing the arc length of the contour of the inclined plane into equal parts, and finally the laying out and unfolding of the cylinder is realized. This method simplifies the unfolding method of the inclined cylinder, and the unfolding method is simple and reliable. It realizes the accurate laying out and unfolding of any inclined cylinder structure, which facilitates the installation of the cylinder and saves production costs.
[0047] Preferably, in step S3, the centerline of the cylinder in the side view intersects the normal section view at points X and Y, and the normal line passing through the center O1 and perpendicular to the centerline of the cylinder intersects the normal section view at points M1 and N1. Points X, Y, M1, and N1 are four quadrant points.
[0048] like Figure 2 As shown, points H and V are projected onto the normal section view along the center line of the cylinder in the side view, resulting in projection point H1 corresponding to point H and projection point V1 corresponding to point V. Point H1 is in the first quadrant and point V1 is in the third quadrant. ∠XO1H1 is determined to be Z degrees. The straight line M1N1 is rotated counterclockwise by Z degrees with O1 as the center to obtain the projection line P1W1 of the major axis section.
[0049] On the normal section diagram, the outline of the cylinder is divided into four quadrants by points X, Y, M1, and N1. Since the projection lines of the minor axis and major axis of the ellipse on the normal section are perpendicular to each other, the projection line of the major axis section can be obtained from the projection line of the minor axis section by means of the angle between the projection line of the major axis section and the horizontal and vertical axes, which simplifies the way to obtain the projection line of the major axis section.
[0050] In other embodiments, the perpendicular line to the projection line of the short axis section can also be drawn directly, and the corner point of the perpendicular line and the outline of the cylinder is the projection line P1W1 of the long axis section.
[0051] Preferably, in step S4, points P1 and W1 are projected onto the side view along the center line of the cylinder to obtain points P and W, and points P and W are connected to obtain the major axis projection line PW passing through the center O.
[0052] The endpoints P and W of the long axis projection line are obtained by projecting points P1 and W1 along the center line of the cylinder. The long axis projection line must be a straight line passing through the center O of the circle. The long axis projection line is obtained by determining the straight line by two points, which is a simple method.
[0053] Preferably, in step S6, when dividing the cylinder outline of the normal section view into equal parts, the first reference point is one of the division points.
[0054] The unfolded point after point Q is the endpoint of the lofted unfolded diagram. The first reference point is one of the equally divided points, which makes it easy to obtain the distance between each unfolded point and the second reference point, and also simplifies the method of equally divided points.
[0055] Preferably, in step S6, there are a total of sixteen division points.
[0056] Sixteen equal division points can divide the circular outline into a sufficient number of arcs, ensuring the accuracy of the lofted development diagram. In other embodiments, the number of division points can be increased or decreased depending on the radius of the cylinder.
[0057] In this embodiment, when dividing the normal cross-section of the cylinder into equal parts, the following points are obtained: M1, A1, B1, C1, D1, E1, F1, G1, N1, G2, F2, E2, D2, C2, B2, and A2. Among them, M1 and N1 are symmetrically arranged with center O1, A1 and A2 are symmetrically arranged with center O1, B1 and B2 are symmetrically arranged with center O1, C1 and C2 are symmetrically arranged with center O1, D1 and D2 are symmetrically arranged with center O1, E1 and E2 are symmetrically arranged with center O1, F1 and F2 are symmetrically arranged with center O1, and G1 and G2 are symmetrically arranged with center O1.
[0058] Project each of the equally divided points onto line segment QT along the center line of the cylinder to obtain the corresponding equally divided projection points: point A, point B, point C, point D, point E, point F, and point G. Among them, the equally divided projection point of point M1 is at point Q, and the equally divided projection point of point N1 is at point T.
[0059] Preferably, in step S7, among the equidistant points, the arc between the two equidistant points on both sides of the first reference point is twice the arc length, and two unfolding points are obtained synchronously with the central projection point as the center.
[0060] Two equally spaced points on either side of the first reference point are arranged symmetrically. Since the equally spaced projection points of the two equally spaced points coincide, the unfolded points are arranged symmetrically about the second reference line and are located on the same second reference line. Therefore, the two unfolded points are obtained by taking the arc between the two equally spaced points on either side of the first reference point as the quasi-synchronous point, which can improve the unfolding efficiency.
[0061] like Figure 3 As shown, in this embodiment, the center projection point M1 of Q is obtained on the first reference line. At each equally divided point of the normal section diagram, arcs A1M1A2, B1M1B2, C1M1C2, D1M1D2, E1M1E2, F1M1F2, G1M1G2, and a complete circle are obtained, with corresponding arc lengths of LA, LB, LC, LD, LE, LF, LG, and LN, respectively. On the second reference line, starting from the... Using the center projection point on a baseline as the center, intercept the corresponding arc length values: LA, LB, LC, LD, LE, LF, LG, LN, and you can obtain the various unfolded points: N1, G1, F1, E1, D1, C1, B1, A1, A2, B2, C2, D2, E2, F2, G2, and N1. Then, smoothly connect these unfolded points with point M1 in sequence to obtain the unfolded line of the bevel contour.
[0062] Preferably, in step S9, the first length L1 of the first generatrix passing through point Q is measured on the cylinder outline, and a reference line segment of the first length L1 is cut off on the first reference line with the second reference point as the endpoint. The endpoint of the reference line segment is the first unfolding point. The second length L2 of the second generatrix passing through point T is measured on the cylinder outline, and the length of the outline segment is L2. The generatrix unfolding point and the first unfolding point are connected to complete the layout unfolding diagram of the oblique cylinder.
[0063] like Figure 3 As shown, the first generatrix is the longest generatrix of the cylinder, and the second generatrix is the shortest generatrix of the cylinder. A length L1 is intercepted on the first baseline to obtain line segment M1S. Lines parallel to line segment M1S are drawn through point N1, and line segment N1S1 of length L2 is intercepted. This is the outline line segment. Connecting the two points S1 completes the layout and development of the inclined cylinder, resulting in the layout and development diagram, as shown. Figure 4 As shown.
[0064] In summary, this invention provides a method for laying out and developing a beveled cylindrical structure. The beveled plane of the cylindrical structure is an elliptical surface, and the minor axis of the elliptical surface is necessarily the diameter of the cylindrical structure and perpendicular to the center line of the cylindrical structure. By drawing a perpendicular line to the center line of the cylindrical structure, the minor axis projection line is obtained. The minor axis and major axis of the elliptical surface are necessarily perpendicular to each other on the normal section, thus obtaining the major axis section projection line and the major axis projection line. Using the major axis projection line as a reference, the actual size line segment QT of the major axis is obtained. The beveled plane is developed by equally dividing the arc length of the beveled plane contour, and finally the laying out and development of the cylindrical structure is achieved. This simplifies the development method of the beveled cylindrical structure, and the development method is simple and reliable. It realizes the accurate laying out and development of any beveled cylindrical structure, facilitates the installation of the cylindrical structure, and saves production costs.
[0065] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.
Claims
1. A method for laying out and developing a slanted cylindrical structure, characterized in that, Includes the following steps: S1. Create the side view and normal section view of the cylinder. The center O of the cylinder in the side view and the center O1 of the cylinder in the normal section view are both located on the center line of the cylinder in the side view. S2, in the side view, draw a perpendicular line from the center O of the cylinder to the center line of the cylinder. The perpendicular line intersects the outline of the inclined opening of the cylinder at points H and V. Connect points H and V to obtain line segment HV. Line segment HV is the minor axis projection line of the inclined plane. S3. Project line segment HV along the centerline of the cylinder onto the normal section diagram to obtain the minor axis projection line H1V1 on the normal section diagram, and obtain the major axis projection line P1W1 perpendicular to the minor axis projection line on the normal section diagram. The centerline of the cylinder in the side view intersects the normal section view at points X and Y. The normal line passing through the center O1 and perpendicular to the centerline of the cylinder intersects the normal section view at points M1 and N1. Points X, Y, M1, and N1 are points in four quadrants. Project points H and V along the center line of the cylinder in the side view to the normal section view to obtain the projection point H1 corresponding to point H and the projection point V1 corresponding to point V. Point H1 is in the first quadrant and point V1 is in the third quadrant. Determine ∠XO1H1 as Z degrees. Rotate the straight line M1N1 counterclockwise by Z degrees with O1 as the center to obtain the projection line P1W1 of the major axis section. S4. Project the long axis section projection line P1W1 along the center line of the cylinder to the side view to obtain the line segment PW that intersects with the contour line of the inclined opening. The line segment PW is the long axis projection line of the inclined opening plane. S5. Draw a perpendicular line from point P to the center line of the cylinder and intersect the extension of the cylinder outline at point Q. Draw a perpendicular line from point W to the center line of the cylinder and intersect the cylinder outline at point T. Connect point Q and point T to obtain line segment QT. S6. Divide the cylinder outline of the normal section view into several equal division points. Project each division point along the cylinder centerline onto line segment QT to obtain the corresponding equal division projection point. The projection point of point Q along the cylinder centerline on the normal section view is the first reference point. Draw the first reference line parallel to the cylinder centerline. The projection point of point Q on the first reference line is the second reference point. S7. Select an equally divided projection point to make a second reference line perpendicular to the first reference line. The intersection of the second reference line and the first reference line is the center projection point. Measure the arc length of the arc between the equally divided point and the first reference point. With the center projection point as one end, cut a projection line segment of the same length as the arc length on the second reference line to obtain the unfolded point of the equally divided projection point. S8. Repeat step S7 to obtain the development points of each equally divided projection point. Then, smoothly connect the second reference point to each development point to obtain the development line of the bevel contour line. S9. Draw parallel lines parallel to the first baseline at both ends of the development line. On these parallel lines, draw the outline segment of the shortest generatrix of the inclined cylinder. The endpoints of the outline segment are the generatrix development points. Connect the two generatrix development points to complete the lofting development diagram of the inclined cylinder. The length of the shortest generatrix is the length of the plate material at the endpoints of the development line after the inclined cylinder is developed. Measure the first length L1 of the first generatrix passing through point Q on the cylinder outline. On the first reference line, cut a reference line segment of the first length L1 with the second reference point as the endpoint. The endpoint of the reference line segment is the first development point. Measure the second length L2 of the second generatrix passing through point T on the cylinder outline. The length of the outline segment is L2. Connect the generatrix development point and the first development point to complete the layout development diagram of the oblique cylinder.
2. The method for laying out and developing the oblique-mouth cylindrical structure according to claim 1, characterized in that, In step S4, points P1 and W1 are projected onto the side view along the center line of the cylinder to obtain points P and W. Connecting points P and W yields the major axis projection line PW passing through the center O.
3. The method for laying out and developing the oblique-mouth cylindrical structure according to claim 1 or 2, characterized in that, In step S6, when dividing the cylinder outline of the normal section view into equal parts, the first reference point is one of the division points.
4. The method for laying out and developing the oblique-mouth cylindrical structure according to claim 3, characterized in that, In step S6, there are a total of sixteen division points.
5. The method for laying out and developing the oblique-mouth cylindrical structure according to claim 3, characterized in that, In step S7, among the equidistant points, the arc between the two equidistant points on both sides of the first reference point is twice the arc length, and two unfolding points are obtained synchronously with the central projection point as the center.