Method and system for detecting a coil spring

Abstract

The invention relates to a method for testing a coil spring, in particular for use in a vehicle, comprising the steps of: S110 providing a gauge of constant diameter in the axial direction of the coil spring in a coil of the coil spring and at least partially abutting the gauge against the inner circumference of the coil spring; S120 providing a plurality of cross lines through the center of the gauge at a determined angular interval in the circumferential direction of the coil spring in a two-dimensional image; S130 determining the diameter of the coil of the coil spring at the angular position represented by each cross line in the two-dimensional image; S140 comparing the difference between the diameters of the coil at each two adjacent angular positions in the helical direction of the coil spring, respectively, with a threshold value; and S150 determining the starting angular position of the opening angle of the coil spring based on the comparison result. The testing efficiency of the coil spring can be improved by means of machine vision measurement technology.

Description

Technical Field

[0001] This invention relates to the field of spring testing, and more specifically to a method for testing helical springs. Furthermore, this invention also relates to a system for testing helical springs. Background Technology

[0002] Coil springs are used in vehicles, especially in chassis suspension systems. During the manufacturing, installation, and actual vehicle operation of coil springs, misalignment of the spring axis, misalignment of spring connection parts (such as spacers), or positional displacement within the vehicle may occur. This not only causes abnormal noises, disturbances, and even wear during vehicle operation, negatively impacting driving comfort, but can also damage the coil spring itself.

[0003] In existing manual inspection methods, it is difficult to find a measurement reference without using a three-dimensional gauge. While three-dimensional measurement technology can replace manual measurement for inspecting helical springs, the technology itself is expensive and increases the amount of data processing required.

[0004] Therefore, there is still a need to improve existing technologies to address at least some of the aforementioned problems. Summary of the Invention

[0005] Based on this, the present invention proposes an efficient solution that not only overcomes the shortcomings of existing technical solutions, but also enables complete and automated inspection in the production process without significantly increasing labor costs by leveraging machine vision measurement technology, thereby improving inspection efficiency.

[0006] According to a first aspect of the present invention, a method for testing a coil spring, particularly used in vehicles, is provided, wherein the method comprises: Step S110: Provide a gauge of constant diameter in the coil of the helical spring along the axial direction of the helical spring to be tested, and make the gauge at least partially abut against the inner circumference of the helical spring. Step S120: In the two-dimensional image, multiple intersecting lines passing through the center of the gauge are provided at defined angular intervals in the circumferential direction of the helical spring; Step S130: In the two-dimensional image, determine the diameter of the spring coil of the helical spring at the angular position represented by each intersecting line; Step S140: Compare the difference between the diameters of the spring coil at every two adjacent angular positions along the helical direction of the spring with a threshold value; and Step S150: Determine the starting angle position of the opening angle of the helical spring based on the comparison results.

[0007] The basic concept of this invention is to detect the starting angle position of the opening angle of a helical spring by means of a physical or virtual gauge in a two-dimensional image through machine vision, thereby achieving complete and automated inspection in the production process without significantly increasing labor costs, thus improving inspection efficiency.

[0008] Advantageous configurations of the technical solution of the present invention can be obtained from the following optional embodiments.

[0009] In an optional embodiment of the method according to the invention, the gauge is configured as a physical gauge or as a virtual gauge generated in a two-dimensional image.

[0010] In an optional embodiment of the method according to the present invention, the intersecting line is either a virtual intersecting line generated in a two-dimensional image or a physical engraving line preset on the gauge.

[0011] In an alternative embodiment of the method according to the invention, the threshold is adjusted in relation to the determined angular interval.

[0012] According to an optional embodiment of the method of the present invention, in step S110, in the two-dimensional image, the gauge is positioned at an initial position on the inner circumference of the spring coil at the upper or lower end of the helical spring as the 0-degree position and then at a 90-degree position along the helical direction of the helical spring to form a detection reference.

[0013] According to an optional embodiment of the method of the present invention, in step S140, if the difference between the diameter at the larger of the two angular positions and the diameter at the smaller of the two angular positions is greater than or equal to the threshold, then in step S150, the larger angular position is determined as the starting angular position of the opening angle of the helical spring.

[0014] In an optional embodiment of the method according to the invention, the diameter of the gauge is adapted to the diameter of the spring coil at the upper or lower end of the helical spring.

[0015] In an alternative embodiment of the method according to the invention, the cross lines are provided at 45-degree angular intervals.

[0016] According to an optional embodiment of the method of the present invention, step S130 includes: Sub-step S131: Generate the extension line of each intersection line in the two-dimensional image; Sub-step S132: Determine the two intersection points of each extension line with the spring coil; Sub-step S133: Calculate the distance between the two intersection points as the diameter of the spring coil at the angular position represented by the intersecting lines.

[0017] According to an optional embodiment of the method of the present invention, in step S130, the inner diameter of the coil of the helical spring at the corresponding angular position is directly measured by manual or machine vision method, and the thickness of the coil at the corresponding angular position is added to the measured inner diameter to obtain the diameter of the helical spring at the corresponding angular position.

[0018] Alternatively, in step S130, the outer diameter of the coil of the helical spring at the corresponding angular position is directly measured manually or by machine vision, and the thickness of the coil at the corresponding angular position is subtracted from the measured outer diameter to obtain the diameter of the helical spring at the corresponding angular position.

[0019] According to a second aspect of the present invention, a system for detecting a helical spring is provided, the system being configured to perform the method according to one of the above embodiments, wherein the system comprises: An image detection module, configured to detect a two-dimensional image of the helical spring; An image processing module is configured to process the detected two-dimensional image to determine the starting angle position of the opening angle of the helical spring.

[0020] In one alternative embodiment of the system according to the invention, the system further includes a physical gauge configured to be inserted into the coil of the helical spring from the upper or lower end of the helical spring along the axial direction of the helical spring to be tested.

[0021] Further features of the invention will become apparent from the claims, drawings, and description of the figures. Features and combinations of features mentioned in the foregoing description, as well as features and combinations of features mentioned in the following description of the figures and / or shown only in the figures, can be used not only in the corresponding specified combinations, but also in other combinations without departing from the scope of the invention. Therefore, the following are also considered to be covered and disclosed by the invention: those not explicitly shown in the figures and not explicitly interpreted, but rather derived from and produced by combinations of separate features derived from the interpreted content. The following combinations of features are also considered to be disclosed: those that do not possess all the features of the originally drafted independent claims. Furthermore, the following combinations of features are considered to be disclosed, especially those exceeding or deviating from the feature combinations defined in the reference relationships of the claims. Attached Figure Description

[0022] The principles, features, and advantages of the invention will be better understood below by referring to the accompanying drawings. In the drawings: Figure 1 A schematic diagram of an embodiment of a system for detecting helical springs according to the present invention is shown; Figure 2 A schematic flowchart illustrating one embodiment of a method for detecting a helical spring according to the present invention is shown; Figure 3 Show Figure 2 The sub-step of step S130 of the method; and Figure 4 Show Figure 2 An illustrative application scenario of the method.

[0023] List of reference numerals 1 System 2. Coil spring 3. Cross lines 4. Extension line 11 Image Detection Module 12 Image Processing Module 13 Virtual or physical gauges 131 Center 100 methods S110-S150 Steps D diameter XY two-dimensional plane Detailed Implementation

[0024] To make the technical problems to be solved, the technical solutions, and the beneficial technical effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and several exemplary embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of protection of this invention.

[0025] In this specification, for convenience, terms such as "middle," "upper," "lower," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer" are used to indicate orientation or positional relationships in conjunction with the accompanying drawings. This is solely for the purpose of facilitating the description and simplification, and does not imply that the device or element referred to has a specific orientation, or is constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this disclosure. The positional relationships of the constituent elements may be appropriately varied depending on the direction in which each constituent element is described. Therefore, the use of terms not limited to those described in the specification may be appropriately replaced as needed.

[0026] Figure 1 A schematic diagram of an embodiment of a system 1 for detecting a helical spring 2 according to the present invention is shown.

[0027] The coil spring 2 can be a steel coil spring used in vehicles or a coil spring made of composite materials, such as fiber composite materials, for example, suspension springs. Due to manufacturing defects or long-term use, the axis of the coil spring 2 may become misaligned or non-concentric. This misalignment can cause the spring support to become misaligned or its installation position to change, resulting in abnormal noises during vehicle operation and affecting vehicle comfort. In addition, this misalignment can also cause damage to the coil spring 2 itself.

[0028] like Figure 1 As shown, the system 1 schematically includes an image detection module 11 and an image processing module 12. The image detection module 11 is used to detect a two-dimensional image of the helical spring 2. Exemplarily, the image detection module 11 may include an industrial camera (e.g., a high-resolution CCD or CMOS camera), an optical lens (e.g., a double telecentric lens), and an illumination source (e.g., a backlight).

[0029] The image processing module 12 is connected to the image detection module 11 and is used to analyze and process the detected two-dimensional image to determine the starting angle position of the opening angle of the helical spring 2. The image processing module 12 can be a computer, industrial control computer, or embedded system with dedicated image processing software, and the image processing module 12 stores programs for performing corresponding analysis and processing.

[0030] In this application, the opening angle should be understood as a parameter characterizing the axial deviation or misalignment of the helical spring, and will be described in detail in the following embodiments. Therefore, the starting angular position of the opening angle can characterize at which angular position the deviation of the helical spring's axis in the two-dimensional plane begins to exceed the allowable value.

[0031] For example, the image processing module 12 can generate a virtual gauge 13 based on a two-dimensional image and add the virtual gauge 13 to the two-dimensional image of the helical spring 2.

[0032] Alternatively, system 1 may also include a physical gauge 13. This physical gauge 13 has a constant diameter and can be inserted from one end into the coil of the helical spring 2 along the axial direction of the helical spring 2 to form a reference during testing.

[0033] Figure 2 A schematic flowchart of one embodiment of a method 100 for testing a coil spring 2 according to the present invention is shown. The method 100 exemplarily includes steps S110 to S150 and can be used... Figure 1 The system 1 shown is used to execute this.

[0034] Below, refer to Figures 2 to 4 And also combined Figure 1 The method 100 is described in detail. Figure 2A schematic flowchart of one embodiment of a method 100 for detecting a helical spring 2 according to the present invention is shown. Figure 3 Show Figure 2 The sub-step of step S130 in method 100, Figure 4 Show Figure 2 The illustrative application scenario of method 100.

[0035] According to this embodiment, in step S110, a gauge 13 of constant diameter is provided in the spring coil of the helical spring 2 along the axial direction of the helical spring 2 to be tested, and the gauge 13 is at least partially abutted against the inner circumference of the helical spring 2.

[0036] As mentioned earlier, gauge 13 can be as follows: Figure 1 The physical gauge 13 shown can also be a virtual gauge 13 generated by the image processing module 12 in a two-dimensional image. For example, the diameter of the gauge 13 is adapted to the diameter of the spring coil at the upper or lower end of the helical spring 2 to ensure a good contact reference can be formed.

[0037] For example, before inspecting the two-dimensional image of the helical spring 2, the physical gauge 13 is manually placed against the inner circumference of the spring coil at the upper or lower end of the helical spring 2 at an initial position designated as the 0-degree position, and also against the spring coil at a 90-degree position along the helical direction of the helical spring 2. Alternatively, after inspecting the two-dimensional image of the helical spring 2, the virtual gauge 13 is placed against the inner circumference of the spring coil at the upper or lower end of the helical spring 2 at an initial position designated as the 0-degree position, and also against the virtual gauge 13 at a 90-degree position along the helical direction of the helical spring 2, thereby forming a clear inspection reference. In other words, by ensuring that the spring coil is in contact with the gauge 13 in both the 0-degree and 90-degree orthogonal directions, the relative positional relationship between the gauge 13 and the spring coil of the helical spring 2 can be accurately determined.

[0038] In step S120, in the two-dimensional image, multiple intersecting lines 3 passing through the center 131 of the gauge 13 are generated at defined angular intervals in the circumferential direction of the helical spring 2.

[0039] The cross line 3 can be a virtual cross line 3 generated by the image processing module 12 in a two-dimensional image, or it can be a physical scribing line preset on the physical gauge 13 when using the physical gauge 13.

[0040] The defined angular interval can be determined based on the detection accuracy. In one embodiment, the cross lines 3 are set at 45-degree angular intervals. Figure 4As shown, in a two-dimensional image (two-dimensional plane XY), starting from an angle position of 0 degrees, a cross line is generated every 45 degrees (as shown by the dashed line), thus forming 4 cross lines on the entire circumference (i.e., 0 degree / 180 degree cross line 3, 45 degree / 225 degree cross line 3, 90 degree / 270 degree cross line 3, and 135 degree / 315 degree cross line 3). Of course, other arbitrary angle intervals can also be set according to requirements, such as 30 degrees or 10 degrees.

[0041] To simplify the explanation, Figure 4 The diagram in Figure 3 schematically indicates only one cross line (90 degrees / 270 degrees).

[0042] In step S130, the diameter of the coil of the helical spring 2 at each angular position represented by the intersection line 3 is determined in the two-dimensional image. Since the coil of the helical spring 2 is in contact with the gauge 13 at both the 0-degree and 90-degree angular positions, the diameter of the coil of the helical spring 2 at each angular position represented by the intersection line 3 can be determined in a simplified manner starting from the 90-degree angular position.

[0043] According to one embodiment, such as Figure 3 As shown, step S130 may include sub-steps S131 to S133 for determining the diameter D.

[0044] In sub-step S131, extension lines of each intersection line 3 are generated in the two-dimensional image. These extension lines extend to both sides of the spring coil until they intersect with the edge of the spring coil.

[0045] In sub-step S132, determine the two intersection points of each extension line 4 with the spring coil.

[0046] In sub-step S133, the distance between the two intersection points is calculated. This distance represents the diameter D of the spring coil at that angular position.

[0047] In another embodiment, in step S130, the inner diameter of the coil of the helical spring 2 can be directly measured manually or by machine vision. Half the thickness of the coil at the corresponding position is added to both sides of the measured inner diameter, that is, one coil thickness is added, to determine the diameter D of the helical spring 2 at the corresponding angular position. Alternatively, the outer diameter of the coil of the helical spring 2 can be directly measured manually or by machine vision, and one coil thickness is subtracted from the measured outer diameter to determine the diameter D of the helical spring 2 at the corresponding angular position.

[0048] In step S140, after obtaining the diameter at each angular position, the difference between the diameters of the spring coil at each of two adjacent angular positions is compared with a threshold along the helical direction of the helical spring 2.

[0049] According to this embodiment, the threshold is adjusted in relation to a defined angular interval. In other words, if the defined angular interval is small, the threshold is adjusted to be smaller accordingly. For example, the threshold corresponding to an angular interval of 10 degrees is less than the threshold corresponding to an angular interval of 45 degrees.

[0050] Then, in step S150, the starting angle position of the opening angle of the helical spring 2 is determined based on the comparison result.

[0051] Specifically, in one embodiment, if the difference between the diameter at the larger angle position and the diameter at the smaller angle position is greater than or equal to a threshold, then the larger angle position is determined as the starting angle position of the opening angle of the helical spring 2.

[0052] exist Figure 4 In the example, the diameter D at two adjacent angular positions of 225 degrees is marked. 225° and the diameter D at 270 degrees 270° These two diameters are determined as described in the previous embodiments. If diameter D 270° With diameter D 225° If the difference is greater than or equal to the threshold, then the 270-degree angle position is determined as the starting angle position of the opening angle of the helical spring 2. Therefore, if the axis misalignment or non-concentricity of the helical spring 2 is detected, it can be determined that the helical spring 2 has a defect in the production process and should be removed from the product as a defective product.

[0053] According to one embodiment, in step S150, while determining the starting angle position of the opening angle, the starting angle position of the opening angle can be stored simultaneously. This allows for statistical analysis of the starting angle positions of the opening angles of each helical spring 2 during subsequent batch inspections, thereby identifying system detection offsets and / or further identifying potential defects or faults in the manufacturing apparatus or process of the helical springs.

[0054] For example, the above-described method 100 of the present invention can also be performed on the upper and / or lower contact surfaces of the helical spring 2 in contact with a solid, such as a vehicle component, and / or on the spring pad.

[0055] The present invention provides a precise and rapid method to determine the initial angle position of the opening angle of a helical spring. A simplified measurement method enables real-time evaluation and sorting, and the recording of a series of measurement data to identify deviation drift. Furthermore, it allows for visual measurement without causing mechanical damage to the spring, and simplifies manual measurement using one-dimensional measuring tools. This solves the technical problems of existing technologies, such as the difficulty in locating measurement references without gauges or the need for expensive three-dimensional measuring equipment.

[0056] Other advantages and alternative embodiments of the invention will be apparent to those skilled in the art. Therefore, the invention is not, in its broader sense, limited to the specific details, representative structures, and exemplary embodiments shown and described. Rather, those skilled in the art can make various modifications and substitutions without departing from the basic spirit and scope of the invention.

Claims

1. A method (100) for testing a coil spring (2), said coil spring (2) particularly used in vehicles, wherein, The method (100) includes: Step S110: A gauge (13) of constant diameter is provided in the spring coil of the helical spring (2) along the axial direction of the helical spring (2) to be tested, and the gauge (13) is at least partially attached to the inner circumference of the helical spring (2); Step S120: In a two-dimensional image, multiple intersecting lines (3) are provided at defined angular intervals in the circumferential direction of the helical spring (2) through the center (131) of the gauge (13). Step S130: In the two-dimensional image, determine the diameter of the spring coil of the helical spring (2) at the angle position represented by each intersection line (3); Step S140: Compare the difference between the diameters of the spring coil at every two adjacent angular positions along the helical direction of the helical spring (2) with a threshold value; and Step S150: Determine the starting angle position of the opening angle of the helical spring (2) based on the comparison results.

2. The method (100) according to claim 1, wherein, The gauge (13) is constructed as a physical gauge (13) or as a virtual gauge (13) generated in a two-dimensional image; and / or The cross line (3) is a virtual cross line (3) generated in a two-dimensional image or a physical engraving (3) preset on the gauge (13); and / or The threshold is adjusted in relation to the determined angular interval.

3. The method (100) according to claim 1 or 2, wherein, In step S110, in the two-dimensional image, the gauge (13) is placed at the initial position on the inner circumference of the spring coil at the upper or lower end of the helical spring (2) as the 0-degree position and then placed at the 90-degree position along the helical direction of the helical spring (2) to form a detection reference.

4. The method (100) according to claim 1, wherein, In step S140, if the difference between the diameter at the larger angle position and the diameter at the smaller angle position is greater than or equal to the threshold, then in step S150, the larger angle position is determined as the starting angle position of the opening angle of the helical spring (2).

5. The method (100) according to claim 3, wherein, The diameter of the gauge (13) is adapted to the diameter of the spring coil at the upper or lower end of the helical spring (2).

6. The method (100) according to any one of claims 1 to 5, wherein, The cross lines (3) are provided at 45-degree angle intervals.

7. The method (100) according to any one of claims 1 to 6, wherein, Step S130 includes: Sub-step S131: Generate the extension line (4) of each intersection line (3) in the two-dimensional image; Sub-step S132: Determine the two intersection points of each extension line (4) with the spring coil; Sub-step S133: Calculate the distance between the two intersection points as the diameter of the spring coil at the angular position represented by the cross line (3).

8. The method (100) according to claim 1, wherein, In step S130, the inner diameter of the coil of the helical spring (2) at the corresponding angular position is directly measured manually or by machine vision, and the thickness of the coil at the corresponding angular position is added to the measured inner diameter to determine the diameter of the helical spring (2) at the corresponding angular position; or In step S130, the outer diameter of the coil of the helical spring (2) at the corresponding angular position is directly measured by manual or machine vision method, and the thickness of the coil at the corresponding angular position is subtracted from the measured outer diameter to obtain the diameter of the helical spring (2) at the corresponding angular position.

9. A system (1) for detecting a helical spring (2), said system (1) being configured to perform the method (100) according to any one of claims 1 to 8, wherein, The system (1) includes: Image detection module (11), the image detection module (11) is configured to detect a two-dimensional image of the helical spring (2); Image processing module (12) is configured to process the detected two-dimensional image to determine the starting angle position of the opening angle of the helical spring (2).

10. The system (1) according to claim 9, wherein, The system (1) further includes a physical gauge (13) configured to be inserted into the coil of the helical spring (2) from the upper or lower end of the helical spring (2) along the axial direction of the helical spring (2) to be tested.

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