A CATIA-based parameterized modeling method for helical spring

Abstract

The present application belongs to the technical field of parameterized modeling of automobile coil springs, and particularly relates to a coil spring parameterized modeling method based on CATIA; first, the starting point and the ending point of the upper end ring of the spring are determined, then the starting point and the ending point of the lower end ring of the spring are determined, and finally the middle ring of the spring is drawn; finally, the spring skeleton line is obtained by combining commands, a circle is drawn at the ending point of the spring skeleton line, and then the spring 3D data is obtained by using the rib command, and the required spring model is realized by associating the formula parameters with the geometric parameters; the present application can meet the requirement of quickly creating a coil spring by using CATIA, is used for guiding the space arrangement and checking in the early stage of the suspension system design, and is suitable for all coil spring modeling based on CATIA.

Description

Technical Field

[0001] This invention belongs to the field of parametric modeling technology for automotive coil springs, specifically relating to a parametric modeling method for coil springs based on CATIA. Background Technology

[0002] Coil springs, as load-bearing components in automobiles, are essential key parts in the automotive industry. Their modeling has always been a bottleneck. CATIA's standard parts library does not include coil springs. Although standard coil springs can be downloaded from relevant websites or referenced from previous spring data models, these coil springs are all rigid parts, cannot deform, and their parameters cannot accurately adapt to vehicle model requirements. Furthermore, their upper and lower interfaces are not compatible with all soft pads, making them unusable for direct use and hindering motion simulation, thus posing challenges to kinematic analysis. Given the widespread use of coil springs, modeling them using traditional methods each time would be extremely labor-intensive and repetitive, resulting in significant time and effort losses. Summary of the Invention

[0003] To overcome the above problems, this invention provides a parametric modeling method for helical springs based on CATIA; to meet the need for rapid creation of helical springs using CATIA, it can be used to guide the early spatial layout and verification of suspension system design, and is applicable to all helical spring modeling based on CATIA.

[0004] A parametric modeling method for helical springs based on CATIA includes the following:

[0005] Step 1. Before drawing, set the characteristic parameters of the helical spring with geometric values ​​as modeling parameters to control the spring shape. The characteristic parameters that need to be set include wire diameter, upper coil inner diameter, number of upper coils, upper coil transition coil, spring mean diameter, spring design height or free height, total number of spring coils, lower coil lift, number of lower coils, number of lower coil transition coils, end position adjustment angle, and lower end reserved gap.

[0006] Step 2. Draw the upper coil of the spring.

[0007] Based on the stiffness and deformation of the upper pad, determine the plane where the upper end coil spring wire axis is located. Based on this plane, the inner diameter of the upper end coil plus the spring wire diameter is the diameter of the upper end coil spring wire axis. Then, adjust the angle parameters according to the number of upper end coils, the number of upper end coil transition coils, the spring middle diameter characteristics, and the end position. Use the connection curve command to obtain the upper end coil spring wire axis. At this time, the starting point and ending point of the upper end coil of the spring have been determined.

[0008] Step 3. Draw the lower coil of the spring.

[0009] Using the spiral curve command, the endpoint of the lower coil spring wire axis is obtained: where the axial distance of the spring wire center = the design height or free height of the spring - 2 * spring wire diameter, and the number of revolutions = the total number of spring coils - the number of transition coils of the upper coil. At this point, the lowest point of the spiral is the endpoint of the lower coil spring wire axis. Based on this point, according to the lower coil lift, the number of transition coils of the lower coil, the number of lower coils, and the lower reserved gap parameters, the lower coil spring wire axis is obtained using the connection curve command. At this point, the starting point and the ending point of the lower coil of the spring are determined.

[0010] Step 4. Draw the middle coil of the spring.

[0011] Based on the end point of the upper coil and the starting point of the lower coil, the axial height of the spring wire center of the working coil = the design height or free height of the spring - 2 * spring wire diameter - lower coil lift - lower reserved gap, and the number of revolutions = the total number of spring coils - the number of upper coil transition coils - the number of lower coil transition coils. At this time, the middle coil of the spring is completed.

[0012] Step 5. Based on the upper end ring, lower end ring, and middle ring of the spring, obtain the spring skeleton line by combining commands. Draw a circle at the end of the spring skeleton line with the diameter of the spring wire. Then use the rib command to obtain the 3D data of the spring.

[0013] Step 6. Replace the geometric values ​​of the feature parameters defined in Step 1 (spring modeling) with the values ​​of the corresponding feature parameters of the spring to be modeled. The spring will then become the required data model.

[0014] The parameter settings for the helical spring before drawing are as follows: wire diameter = 19.8mm, upper coil inner diameter = 64mm, number of upper coils = 0.625, upper coil transition coils = 1.25, spring mean diameter = 128.2mm, spring design height = 252mm, free height = 342.8mm, total number of spring coils = 6.36, lower coil lift = 21mm, lower coils = 0.75, lower coil transition coils = 1, end position adjustment angle = -20deg, lower end clearance = 4mm.

[0015] In step 1, the inner diameter of the upper coil of the spring is determined based on the size of the pad.

[0016] The method for modifying the numerical values ​​of the corresponding characteristic parameters of the spring in step 6 is as follows:

[0017] 6.1 After clicking the formula button in the toolbar, a pop-up window will appear. Click "New Type Parameter" to create a new feature parameter. Name the parameter the feature parameter to be associated and fill in the required value of the feature parameter in the length field. After clicking "OK", a new parameter will be added to the structure tree, in which the newly created feature parameter and its value will be displayed.

[0018] 6.2 In the structure tree, find the feature parameter whose value you want to modify, right-click on the feature parameter, and then modify the specific value of the corresponding feature parameter through formula editing.

[0019] The beneficial effects of this invention are:

[0020] This invention establishes a parametric model of helical springs based on CATIA. If a helical spring is needed, the target helical spring can be obtained by simply modifying the relevant parameters according to the upper and lower pads and the spring's requirements. Compared to traditional modeling methods, the CATIA-based parametric modeling method for helical springs can significantly improve work efficiency. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0022] Figure 1 A schematic diagram of the upper coil of the spring is drawn for this invention.

[0023] Figure 2 A schematic diagram of the lower end coil of the spring is shown for this invention.

[0024] Figure 3 A schematic diagram of another part of the lower end coil of the spring is shown for this invention.

[0025] Figure 4 A schematic diagram of another part of the spring's intermediate coil is shown for this invention.

[0026] Figure 5 A schematic diagram showing the combination of the upper end coil, the lower end coil, and the middle coil of the spring is provided for this invention.

[0027] Figure 6 A schematic diagram of the spring model is drawn for this invention.

[0028] Figure 7 This is a schematic diagram showing the relationship between the formula parameters and geometric parameters of this invention.

[0029] Figure 8 This is a schematic diagram showing the spring wire diameter after associating the formula parameters and geometric parameters of the present invention.

[0030] Figure 9 This is a schematic diagram of the modified geometric parameters in this invention.

[0031] Figure 10 This is another schematic diagram illustrating the modification of geometric parameters in this invention.

[0032] Figure 11 This is a schematic diagram of the pop-up window when modifying geometric parameters according to the present invention.

[0033] Figure 12 This is a schematic diagram showing the parameters in the structure tree of the present invention. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0035] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0037] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0038] Example 1

[0039] A parametric modeling method for helical springs based on CATIA includes the following:

[0040] The creation of 3D spring data consists of three main parts: the upper coil, the middle coil, and the lower coil. The detailed steps are as follows:

[0041] Step 1. Before drawing, assign set data, i.e., geometric values, to the characteristic parameters of the helical spring as modeling parameters to control the spring shape. The characteristic parameters that need to be set include the wire diameter, the inner diameter of the upper coil, the number of upper coils, the transition coil of the upper coil, the spring mean diameter, the spring design height (spring height under the overall vehicle design posture) or free height (free height is used to create spring data in a free state, and design height is used to create spring data in the design posture; this method can support the creation of spring models in any posture, and this embodiment takes the design posture as an example), the total number of spring coils, the lower coil lift, the number of lower coils, the number of lower coil transition coils, the end position adjustment angle, and the lower end reserved gap;

[0042] Step 2. Draw the upper coil of the spring.

[0043] In CATIA software, the plane containing the upper coil spring wire axis is determined based on the stiffness and deformation of the upper pad. Using this plane as a basis, the inner diameter of the upper coil plus the spring wire diameter is the upper coil spring wire axis diameter. Then, the angle parameters are adjusted according to the number of upper coils, the number of upper coil transition coils, the spring middle diameter characteristics, and the end position. The upper coil spring wire axis is obtained using the connection curve command. At this point, the start and end points of the upper coil of the spring are determined.

[0044] Step 3. Draw the lower coil of the spring.

[0045] Using the spiral curve command, the endpoint of the lower coil spring wire axis is obtained: where the axial distance of the spring wire center = the design height or free height of the spring - 2 * spring wire diameter, and the number of revolutions = the total number of spring coils - the number of transition coils of the upper coil. At this point, the lowest point of the spiral is the endpoint of the lower coil spring wire axis. Based on this point, according to the lower coil lift, the number of transition coils of the lower coil, the number of lower coils, and the lower reserved gap parameters, the lower coil spring wire axis is obtained using the connection curve command. At this point, the starting point and the ending point of the lower coil of the spring are determined.

[0046] Step 4. Draw the middle coil of the spring.

[0047] Based on the end point of the upper coil and the starting point of the lower coil, the axial height of the spring wire center of the working coil = the design height or free height of the spring - 2 * spring wire diameter - lower coil lift - lower reserved gap, and the number of revolutions = the total number of spring coils - the number of upper coil transition coils - the number of lower coil transition coils. At this time, the middle coil of the spring is completed.

[0048] Step 5. Based on the upper end ring, lower end ring, and middle ring of the spring, obtain the spring skeleton line by combining commands. Draw a circle at the end of the spring skeleton line with the diameter of the spring wire. Then use the rib command to obtain the 3D data of the spring.

[0049] Step 6. Replace the geometric values ​​of the arbitrarily defined feature parameters in Step 1 (spring modeling) with the values ​​of the corresponding feature parameters of the spring to be modeled. After this step is completed, the parametric model of the spring is finished. In this way, you can modify the parameters in the parameter table at will, and the spring will become the required data model.

[0050] The parameter settings for the helical spring before drawing are as follows: wire diameter = 19.8mm, upper coil inner diameter = 64mm, number of upper coils = 0.625, upper coil transition coils = 1.25, spring mean diameter = 128.2mm, spring design height = 252mm, free height = 342.8mm, total number of spring coils = 6.36, lower coil lift = 21mm, lower coils = 0.75, lower coil transition coils = 1, end position adjustment angle = -20deg, lower end clearance = 4mm.

[0051] In step 1, the inner diameter of the upper coil of the spring is determined based on the size of the pad.

[0052] The method for modifying the numerical values ​​of the corresponding characteristic parameters of the spring in step 6 is as follows:

[0053] 6.1 After clicking the formula button f(x) in the toolbar, a pop-up window will appear. Click "New Type Parameter" to create a new feature parameter. Name the parameter the feature parameter to be associated and fill in the required value of the feature parameter in the length column. After clicking "OK", a new parameter will be added to the structure tree, in which the newly created feature parameter and its value will be displayed.

[0054] 6.2 In the left-hand tree structure, find the feature parameter whose value you want to modify, right-click on the feature parameter, and then modify the specific value of the corresponding feature parameter through formula editing.

[0055] Example 2

[0056] The key parameters controlling the shape of a spring include wire diameter, inner diameter of the upper coil, number of upper coils, transition coil of the upper coil, mean diameter of the spring, design height, free height, total number of spring coils, lift of the lower coil, number of lower coils, number of transition coils of the lower coil, and adjustment angle of the end position. These parameters are directly related to the axle load of the vehicle, leverage ratio, spring stiffness, upper and lower pad data, and spring height.

[0057] Therefore, before performing parametric design of the spring, a set of data is attached to the characteristic parameters of the helical spring as modeling parameters to control the spring shape. The characteristic parameters selected in this paper are: "Wire Diameter" = 19.8mm, "Upper Coil Inner Diameter" = 64mm, "Number of Upper Coils" = 0.625, "Upper Coil Transition Coils" = 1.25, "Spring Mean Diameter" = 128.2mm, "Design Height" = 252mm, "Free Height" = 342.8mm, "Total Number of Spring Coils" = 6.36, "Lower Coil Lift" = 21mm, "Lower Coil Number of Lower Coils" = 0.75, "Lower Coil Transition Coils" = 1, "End Position Adjustment Angle" = -20deg, and "Lower End Reserved Clearance" = 4mm. Based on these characteristic parameters, the corresponding data model is drawn. At this time, the formula parameters have not yet been associated with the spring geometric parameters, so the "Parameters" and "Relationships" items are not present in the structure tree on the left side of the CATIA operation interface.

[0058] (I) The drawing of 3D spring data mainly consists of three parts: the upper coil, the middle coil, and the lower coil. The detailed steps are as follows:

[0059] 1. Draw the upper coil of the spring.

[0060] Based on the stiffness and deformation of the upper pad, determine the plane containing the upper coil spring wire axis. Using this plane as a basis, determine the inner diameter of the upper coil according to the pad size (64mm in this example; the actual size depends on a reasonable match with the pad size). Therefore, the upper coil inner diameter + spring wire diameter = 83.8mm is the upper coil spring wire axis diameter. Then, based on the number of upper coils, the number of transition coils, and the spring's mean diameter characteristic parameters, use the connection curve command to obtain the upper coil spring wire axis. Figure 1 At this point, the starting and ending points of the upper coil of the spring have been determined;

[0061] 2. Draw the lower coil of the spring.

[0062] Using the spiral curve command, the endpoint of the lower coil wire axis of the spring is obtained, such as... Figure 2 The axial distance between the spring wire centers (i.e., the distance from the beginning of the working coil to the end of the lower coil below the upper coil, this distance is the axial distance between the spring wire centers) = spring height under the overall vehicle design posture - 2 * spring wire diameter, rotations = total number of spring coils - number of transition coils of the upper coil. At this point, the lowest point of the helix is ​​the endpoint of the lower coil spring wire axis. Based on this point, according to the lower coil lift, the number of transition coils of the lower coil, the number of lower coils, and the lower reserved gap parameters, the lower coil spring wire axis is obtained using the connection curve command, such as... Figure 3 At this point, the starting and ending points of the lower coil of the spring have been determined;

[0063] 3. Draw the middle coil of the spring.

[0064] Based on the end point of the upper coil and the starting point of the lower coil, such as Figure 4 The axial height of the spring wire center of the working spring coil = spring height under the overall vehicle design attitude - 2 * spring wire diameter - lower end coil lift - lower end reserved gap, and the number of revolutions = total number of spring coils - number of upper end coil transition coils - number of lower end coil transition coils. At this time, the middle spring coil is drawn.

[0065] 4. Based on the upper coil, lower coil, and middle coil of the spring, obtain the spring skeleton line by combining commands. Draw a circle at the end of the spring skeleton line with a diameter equal to the diameter of the spring wire, such as... Figure 5 Next, the rib command is used to obtain the 3D data of the spring. The data model is as follows: Figure 6 ;

[0066] (II) Relationship between Formula Parameters and Geometric Parameters

[0067] Since the steps for creating parameters in parametric modeling are identical and numerous, this article only uses one parameter—the wire diameter—as an example. Clicking the formula button f(x) in the toolbar will bring up a pop-up window as follows: Figure 7 As shown, after selecting the length, click "New Type Parameter" to create a new feature parameter and name it "Spring Wire Diameter," then fill in the parameter value—"Spring Wire Diameter"—19.8mm. After clicking "OK," a new parameter will appear in the structure tree, and the newly created feature parameter—"Spring Wire Diameter"—will be displayed. Figure 8 As shown;

[0068] like Figure 9 As shown, then find the geometric parameter to be associated with the feature parameter—spring wire diameter—in the left-hand structure tree. Here, "circle.6" defines the outline of rib "rib.3," and its diameter, i.e., the "spring wire diameter," is 19.8 mm. Right-click and select "diameter = 19.8," then proceed as follows... Figure 10 Click "Edit Formula" in the indicated path;

[0069] Then a pop-up window will appear as follows Figure 11 As shown, double-click "Spring Wire Diameter" to add it to the formula list. Since the formula "Spring Wire Diameter" matches the actual spring wire diameter (19.8mm), no further addition to the formula is needed; simply click "OK". At this point, a new "Relationship" item will appear in the structure tree, containing the function relationship information just created, such as... Figure 12 As shown.

[0070] The association between this parameter and the geometric constraint is now complete. Similarly, after associating all the above parameters with their corresponding geometric constraints, the association between the formula parameters and the spring geometric parameters is complete.

[0071] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the scope of protection of the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, any person skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention within the scope of the technology disclosed in the present invention. These simple modifications are all within the scope of protection of the present invention.

[0072] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0073] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A parametric modeling method for helical springs based on CATIA, characterized in that, Includes the following: Step 1. Before drawing, set the characteristic parameters of the helical spring with geometric values ​​as modeling parameters to control the spring shape. The characteristic parameters that need to be set include wire diameter, upper coil inner diameter, number of upper coils, upper coil transition coil, spring mean diameter, spring design height or free height, total number of spring coils, lower coil lift, number of lower coils, number of lower coil transition coils, end position adjustment angle, and lower end reserved gap. Step 2. Draw the upper coil of the spring. Based on the stiffness and deformation of the upper pad, determine the plane where the upper end coil spring wire axis is located. Based on this plane, the inner diameter of the upper end coil plus the spring wire diameter is the diameter of the upper end coil spring wire axis. Then, adjust the angle parameters according to the number of upper end coils, the number of upper end coil transition coils, the spring middle diameter characteristics, and the end position. Use the connection curve command to obtain the upper end coil spring wire axis. At this time, the starting point and ending point of the upper end coil of the spring have been determined. Step 3. Draw the lower coil of the spring. Using the spiral curve command, the endpoint of the lower coil spring wire axis is obtained: where the axial distance of the spring wire center = the design height or free height of the spring - 2 * spring wire diameter, and the number of revolutions = the total number of spring coils - the number of transition coils of the upper coil. At this point, the lowest point of the spiral is the endpoint of the lower coil spring wire axis. Based on this point, according to the lower coil lift, the number of transition coils of the lower coil, the number of lower coils, and the lower reserved gap parameters, the lower coil spring wire axis is obtained using the connection curve command. At this point, the starting point and the ending point of the lower coil of the spring are determined. Step 4. Draw the middle coil of the spring. Based on the end point of the upper coil and the starting point of the lower coil, the axial height of the spring wire center of the working coil = the design height or free height of the spring - 2 * spring wire diameter - lower coil lift - lower reserved gap, and the number of revolutions = the total number of spring coils - the number of upper coil transition coils - the number of lower coil transition coils. At this time, the middle coil of the spring is completed. Step 5. Based on the upper end ring, lower end ring, and middle ring of the spring, obtain the spring skeleton line by combining commands. Draw a circle at the end of the spring skeleton line with the diameter of the spring wire. Then use the rib command to obtain the 3D data of the spring. Step 6. Replace the geometric values ​​of the feature parameters defined in Step 1 (spring modeling) with the values ​​of the corresponding feature parameters of the spring to be modeled. The spring will then become the required data model.

2. The parametric modeling method for helical springs based on CATIA according to claim 1, characterized in that, The parameter settings for the helical spring before drawing are as follows: wire diameter = 19.8mm, upper coil inner diameter = 64mm, number of upper coils = 0.625, upper coil transition coils = 1.25, spring mean diameter = 128.2mm, spring design height = 252mm, free height = 342.8mm, total number of spring coils = 6.36, lower coil lift = 21mm, lower coils = 0.75, lower coil transition coils = 1, end position adjustment angle = -20deg, lower end clearance = 4mm.

3. The parametric modeling method for helical springs based on CATIA according to claim 1, characterized in that, In step 1, the inner diameter of the upper coil of the spring is determined based on the size of the pad.

4. The parametric modeling method for helical springs based on CATIA according to claim 1, characterized in that, The method for modifying the numerical values ​​of the corresponding characteristic parameters of the spring in step 6 is as follows: 6.1 After clicking the formula button in the toolbar, a pop-up window will appear. Click "New Type Parameter" to create a new feature parameter. Name the parameter the feature parameter to be associated and fill in the required value of the feature parameter in the length field. After clicking "OK", a new parameter will be added to the structure tree, in which the newly created feature parameter and its value will be displayed. 6.2 In the structure tree, find the feature parameter whose value you want to modify, right-click on the feature parameter, and then modify the specific value of the corresponding feature parameter through formula editing.

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