Modeling method for extracting tire profile diagram

Abstract

The invention provides a modeling method for extracting a tire profile diagram, which comprises the following steps of: scanning a tire by using 3D scanning equipment to obtain tire scanning models in various pressure states; fitting a rotating shaft of the tire scanning model by using three-dimensional software; creating a radial section of the tire contour passing through the rotating shaft, and extracting a section point cloud curve of the tire contour; transforming the rotation axis and the section point cloud curve into an absolute coordinate system of the three-dimensional software; and carrying out miscellaneous point deletion on the section point cloud curve to obtain a tire contour curve graph, and establishing an incidence relation between a real contour graph and a tire theoretical design drawing through a method of scanning a tire model and reversely fitting a tire contour by using three-dimensional software and then reversely fitting the contour. Data support and contour expansion and contraction trend judgment are provided for new product development, the contour design success rate is improved, the development period is shortened, and the development cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of tire design, and in particular to a modeling method for extracting a tire contour map. Background Art

[0002] Tires are not rigid objects. Their profile will change with the inflation pressure. The theoretical profile of the tire design (such as Figure 7 The actual profile of the tire under various air pressure conditions is different from the theoretical profile of the tire (as shown in the figure). Therefore, it is necessary to establish a database of the relationship between the theoretical profile and the actual profile of the tire to guide R&D personnel to determine the trend of profile changes and optimize profile design, and also to prepare for the research of simulation analysis and tire performance testing.

[0003] At present, conventional tire contour detection includes: circumference of the tire at the maximum turning diameter when inflated, tire running surface width, tire section width, etc. The current data cannot fully reflect the changing trend of tire contours and contour curve parameters under different air pressure conditions. With the refined research on tire performance, more accurate contour change trends, curve data and models are needed to support tire performance research. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies of the above-mentioned technology and provide a modeling method for extracting tire contour map.

[0005] To this end, the present invention provides a modeling method for extracting a tire contour map, comprising the following steps:

[0006] S1. Use 3D scanning equipment to scan the tire to obtain tire scanning models in various pressure states;

[0007] S2, using three-dimensional software to fit the rotation axis of the tire scanning model;

[0008] S3, creating a radial section of the tire profile passing through the rotary axis, and extracting a cross-sectional point cloud curve of the tire profile;

[0009] S4, transforming the rotation axis and the cross-sectional point cloud curve into the absolute coordinate system of the three-dimensional software;

[0010] S5. Deleting the clutter points of the cross-sectional point cloud curve to obtain a tire profile curve diagram.

[0011] Preferably, the tire scanning model includes tire scanning model 1 and tire scanning model 2, the tire scanning model 1 is in a non-inflated state without a rim installed, and the tire scanning model 2 is in multiple inflation states with a rim installed.

[0012] Preferably, the method for fitting the rotating axis by the tire scanning model 1 is to fit the circumferential air lines on both sides of the tire contour, fit two circles, and connect the centers of the two circles to obtain the rotating axis 1. The method for fitting the rotating axis by the tire scanning model 2 is to fit the ridges of the intersection of the two circumferential surfaces on both sides of the rim, fit two circles, and connect the centers of the two circles to obtain the rotating axis 2.

[0013] Preferably, a plurality of positioning target points are affixed to the tire, wherein the positioning target points are circle patches with a black background, and a white circle filled with fluorescent material is arranged at the center of the circle patches with a black background.

[0014] Preferably, the positioning target point is attached to a smooth surface of the tire 3 mm away from the tread groove, the spacing between the multiple positioning target points is 80-100 mm, and the multiple positioning target points are arranged in a grid shape.

[0015] Preferably, the rotation axis coincides with one of the axes of the absolute coordinate system.

[0016] Preferably, the miscellaneous points include tire hair, pore marks and points deviating from the main line tolerance range, and the main line tolerance range is ±0.2 mm.

[0017] Preferably, the tire profile curve diagram includes tire outer diameter, running surface width, running surface height, section width, sidewall height on the horizontal axis, crown arc, shoulder arc and sidewall arc.

[0018] Preferably, the diameter of the white circle is 3 mm or 6 mm.

[0019] The beneficial effects of the present invention are as follows: the present invention provides a modeling method for extracting a tire contour map, which has the following beneficial effects.

[0020] By scanning the tire model and using 3D software to reverse fit the tire contour, and then by reverse fitting the contour, we can obtain the values ​​of the key design points of the tire contour, the contour curve change trend, the arc value of the contour curve, etc., which can accurately reflect the relationship between the real contour map and the theoretical design map under various tire pressure states, and establish a correlation relationship and design database between the real contour map and the tire theoretical design map, providing data support for the development of new products and the judgment of the contour expansion and contraction trend, improving the success rate of contour design, shortening the development cycle, and reducing development costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a flow chart of a tire profile extraction modeling method according to an embodiment of the present invention;

[0022] Figure 2 is a fitting diagram for positioning a target point in an embodiment of the present invention;

[0023] Figure 3 is a triangular mesh model diagram of a tire scanning model 2 in an embodiment of the present invention;

[0024] Figure 4 is a fitting reference diagram of the rotation axis of the tire scanning model 2 in an embodiment of the present invention;

[0025] Figure 5 is a fitting reference diagram of the rotation axis of the tire scanning model 1 in an embodiment of the present invention;

[0026] Figure 6 is a schematic diagram of a radial cross section and a radial coordinate system of a tire profile in an embodiment of the present invention;

[0027] Figure 7 is a schematic diagram of a theoretical tire profile in the background art;

[0028] Figure 8 is a real tire profile image after fitting using three-dimensional software in an embodiment of the present invention;

[0029] Fig. 9 is a tire profile diagram of 0Kpa and without a rim installed in an embodiment of the present invention;

[0030] Fig.10 is a tire profile diagram of 0Kpa and mounted rim in an embodiment of the present invention;

[0031] Fig.11 is a tire profile diagram of 18Kpa in an embodiment of the present invention;

[0032] Fig.12 It is a tire profile diagram of 180Kpa in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments to help understand the content of the present invention. The methods used in the present invention are all conventional methods unless otherwise specified; the raw materials and devices used are all conventional commercial products unless otherwise specified.

[0034] Example:

[0035] like Figures 1 to 12 As shown, the present invention provides a modeling method for extracting a tire contour map, comprising the following steps:

[0036] Step 1: Use a 3D scanning device to scan the tire to obtain tire scanning models in various pressure states, wherein the tire scanning models include tire scanning model 1 and tire scanning model 2, wherein the tire scanning model 1 is a model in a non-inflated state without a rim installed, and the tire scanning model 2 is a model in which a rim is installed in various inflated states, and the pressure values ​​of the various full states are 0 kPa, 18 kPa and 180 kPa respectively;

[0037] like Figure 2 As shown, first, a plurality of positioning target points are affixed to the tire. The positioning target points are black-bottom circle patches. A white circle filled with fluorescent material is arranged in the center of the black-bottom circle patch. The diameter of the white circle is 3mm or 6mm. The diameter of the white circle recognized by the 3D scanning device in this embodiment is preferably 6mm, but it is not limited to this diameter. The diameter of the white circle is determined according to the specific 3D scanning device. The positioning target point is affixed to the glossy position of the tire 3mm away from the groove to avoid covering the details of the tire. For semi-steel tires, because the tire is black and absorbs light too strongly, the grooves within 2mm in width are often ignored and not scanned. The target point can be affixed to the narrow groove. The spacing between the plurality of positioning target points is 80mm to 100mm, and the plurality of positioning target points are arranged in a mesh. For tires mounted with rims, a plurality of positioning target points are also affixed to the rims to facilitate scanning.

[0038] After the positioning target points are fitted, the handheld laser scanner is aimed at the positioning target points on the tire to scan, and the tire is identified and positioned according to the positioning target points. Then the handheld 3D scanner is used to scan the details of the tire to obtain the point cloud model of the tire, and the STL file can be output to convert it into a triangular mesh surface model, such as Figure 3 shown.

[0039] Step 2: Use 3D software to fit the rotation axis of the tire scanning model, the 3D software is UG;

[0040] When the scanning device scans the tire, a temporary coordinate system will be randomly established. When the scanned model is imported into the 3D software, the temporary coordinate system will not be recognized. Therefore, it is necessary to fit the rotation axis of the tire model as the axis of the scanning tire model coordinate system and the contour rotation axis.

[0041] like Figure 5 As shown, the method for fitting the rotation axis of the tire scanning model 1 is to fit the circumferential air lines on both sides of the tire contour, fit two circles, and connect the centers of the two circles to obtain the rotation axis 1; as shown Figure 4 As shown, the method of fitting the rotation axis of the second tire scanning model is to fit two circles along the ridges of the two intersecting surfaces of the circumference on both sides of the rim, and connect the centers of the two circles to obtain the second rotation axis.

[0042] Step 3: creating a radial section of the tire profile passing through the rotary axis, and extracting a cross-sectional point cloud curve of the tire profile;

[0043] like Figure 6As shown in the figure, after the rotation axis of the tire model is confirmed, a radial section of the tire passing through the rotation axis is created, and the point cloud curve of the triangular mesh surface model and the section is solved, that is, the tire contour point cloud curve. This point cloud curve cannot directly express the curve data.

[0044] The tire theoretical design profile diagram is the profile of the radial cross section of the tire, and a complete tire profile can be obtained by rotating 360 degrees around the rotation axis.

[0045] Step 4: transform the rotation axis and the cross-sectional point cloud curve into the absolute coordinate system of the three-dimensional software;

[0046] like Figure 6 As shown, through the three-dimensional software, the rotating axis of the fitting model is used as a reference, and the rotating axis and the tire contour point cloud curve are transformed into the three-dimensional software absolute coordinate system. The rotating axis coincides with one of the axes of the absolute coordinate system. In this embodiment, the rotating axis coincides with the Y-axis of the absolute coordinate system, and effective positioning is performed, thereby facilitating the output of the tire contour curve diagram. The output can be used as a measurement reference to read the contour value and measure the tire rotation diameter, etc., and it is also convenient for fitting the pattern.

[0047] Step 5: Delete the noise points of the cross-section point cloud curve to obtain a tire contour curve diagram.

[0048] The tire contour point cloud curve in the absolute coordinate system is removed after removing the noise points and the points that deviate from the main line tolerance range, and then the main line of the tire contour point cloud curve is fitted by the arc to obtain the tire contour. After conversion and mapping, the final tire contour curve is formed, as shown in Figures 8 to 12 shown.

[0049] The miscellaneous points include tire hair, pore marks and points that deviate from the main line tolerance range, and the main line tolerance range is ±0.2mm.

[0050] The tire profile curve diagram includes the following values: tire outer diameter OD, running surface width TDW, running surface height h, section width SW, sidewall height SH2 on the horizontal axis, crown arc R, shoulder arc SHR, and sidewall arc SR. The above values ​​can fully reflect the parameters of the profile curve and the changing trend of the tire profile, which is convenient for detailed research on tire performance.

[0051] like Figures 10 to 12 As shown, as the air pressure increases, the tire outer diameter OD value will increase and tend to be stable after increasing, and the section width SW will decrease and tend to be stable as the air pressure increases, providing effective data support for the subsequent tire profile design.

[0052] In the description of the present invention, it is necessary to understand that the terms "left", "right", "up", "down", "top", "bottom", "front", "back", "inside", "outside", "back", "middle", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0053] However, what is described above is only a specific embodiment of the present invention and should not be used to limit the scope of implementation of the present invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the scope of protection of the present invention should still fall within the scope covered by the claims of the present invention.

Claims

1. A modeling method for extracting a tire contour map, characterized in that: The steps include: S1. Use 3D scanning equipment to scan the tire to obtain tire scanning models in various pressure states; S2, using three-dimensional software to fit the rotation axis of the tire scanning model; S3, creating a radial section of the tire profile passing through the rotary axis, and extracting a cross-sectional point cloud curve of the tire profile; S4, transforming the rotation axis and the cross-sectional point cloud curve into the absolute coordinate system of the three-dimensional software; S5. Deleting the clutter points of the cross-sectional point cloud curve to obtain a tire profile curve diagram.

2. A modeling method for extracting a tire contour map according to claim 1, characterized in that: The tire scanning model includes tire scanning model 1 and tire scanning model 2. The tire scanning model 1 is in a non-inflated state without a rim installed, and the tire scanning model 2 is in multiple inflation states with a rim installed.

3. A modeling method for extracting a tire contour map according to claim 2, characterized in that: The method for fitting the rotating axis by the tire scanning model 1 is to fit the circumferential air lines on both sides of the tire contour, fit two circles, and connect the centers of the two circles to obtain the rotating axis 1. The method for fitting the rotating axis by the tire scanning model 2 is to fit the ridge lines intersecting the two surfaces of the circumference on both sides of the rim, fit two circles, and connect the centers of the two circles to obtain the rotating axis 2.

4. A modeling method for extracting a tire contour map according to claim 1, characterized in that: A plurality of positioning target points are affixed to the tire, wherein the positioning target points are circle patches with a black background, and a white circle filled with fluorescent material is arranged at the center of the circle patches with a black background.

5. A modeling method for extracting a tire contour map according to claim 4, characterized in that: The positioning target point is attached to the smooth surface of the tire 3 mm away from the tread groove, the spacing between the multiple positioning target points is 80 to 100 mm, and the multiple positioning target points are arranged in a grid shape.

6. A modeling method for extracting a tire contour map according to claim 1, characterized in that: The rotation axis coincides with one of the axes of the absolute coordinate system.

7. A modeling method for extracting a tire contour map according to claim 1, characterized in that: The miscellaneous points include tire hair, pore marks and points that deviate from the main line tolerance range, and the main line tolerance range is ±0.2mm.

8. The modeling method for extracting a tire contour map according to claim 1, characterized in that: The tire profile curve diagram includes tire outer diameter, running surface width, running surface height, section width, sidewall height on the horizontal axis, crown arc, shoulder arc and sidewall arc.

9. A modeling method for extracting a tire contour map according to claim 4, characterized in that: The diameter of the white circle is 3 mm or 6 mm.

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