Method for testing the adhesion of a quieting veil to a tire

Abstract

The application discloses a kind of mute cotton and tire adhesion performance test method, it is characterized in that, comprising the following steps: S1, in the state of no pressure, first mute cotton and second mute cotton are pasted in the interior of tire along the direction of motion of tire;Wherein, the length of first mute cotton is greater than the length of tire ground mark long axis;The length of second mute cotton is less than the length of tire ground mark long axis;S2, the interior of tire is pressurized, and first mute cotton and second mute cotton are adhered to the interior of tire;S3, after pressurization, tire is carried out load simulation road driving.Compared with prior art, the beneficial effects of the present application are: by analyzing various different factors that tire in driving process can produce the influence of mute cotton, and then design corresponding test mode, so that it can better judge the adhesion performance of mute cotton and tire.

Description

Technical Field

[0001] This invention belongs to the field of tire performance testing, specifically relating to a test method for the adhesion performance of noise-reducing foam to tires. Background Technology

[0002] Electric vehicles, due to their inherent characteristics, produce very low noise levels, thus requiring tires with significantly higher noise reduction performance than conventional gasoline-powered vehicles. Especially with the increasing market share of electric vehicles, major manufacturers have launched quiet tire products to meet market demands.

[0003] Currently, the installation method for sound-absorbing foam tires typically involves bonding multiple sections of sound-absorbing foam to the inner tread of the tire. However, the indoor testing methods for passenger car tire performance mainly rely on the GB4502-2016 standard, which does not include testing for the adhesion performance between the tire inner tread and the sound-absorbing foam. Therefore, related testing methods are still in the gaps in the field. Summary of the Invention

[0004] Details of one or more embodiments of the present invention are set forth in the following drawings and description to make other features, objects and advantages of the present application more readily apparent.

[0005] This invention provides a test method for the adhesion performance between sound-absorbing cotton and tires. By analyzing the influence of various factors on the sound-absorbing cotton during tire operation, a corresponding test method is designed to better determine the adhesion performance between the sound-absorbing cotton and tires.

[0006] This invention discloses a method for testing the adhesion performance of sound-absorbing cotton to tires, comprising the following steps:

[0007] S1. Under no-pressure conditions, the first and second sound-absorbing cotton are adhered to the inside of the tire along the tire's direction of movement; wherein, the length of the first sound-absorbing cotton is greater than the long axis of the tire contact patch; and the length of the second sound-absorbing cotton is less than the long axis of the tire contact patch.

[0008] S2. Perform staged inflation of the tire interior to make the first and second sound-absorbing cotton adhere to the tire interior.

[0009] S3. Perform load simulation road driving on the inflated tires.

[0010] In some implementations, the length of the major axis of the tire contact patch is calculated as follows:

[0011] L = 2 * R * sinα (Formula 1);

[0012] α=arccos((Ra) / R) (Formula 2);

[0013] a = k * b (Formula 3);

[0014] in,

[0015] L represents the length of the major axis of the tire contact patch, in millimeters;

[0016] R is the tire radius, in millimeters;

[0017] 'a' represents the tire deflection, in millimeters.

[0018] k is the tire sink rate, 0.2≦k≦0.3;

[0019] b represents the tire end face height, in millimeters;

[0020] The lengths of the first and second sound-absorbing foams are calculated as follows:

[0021] The length of the first silencing foam is L+2*c, in millimeters, and k=0.3;

[0022] The length of the second sound-silencing foam is L-2*c, in millimeters, and k = 0.2;

[0023] c represents the thickness of the sound-absorbing foam, in millimeters.

[0024] In some implementations, the staged pressurization method is as follows:

[0025] A1. Park immediately after inflating the tire to its first pressure;

[0026] A2. After inflating the tire to the second pressure, park for the second time;

[0027] A3. After inflating the tire to the third pressure, leave it for the third time.

[0028] A4. Adjust the tire pressure to the third pressure setting;

[0029] in,

[0030] The first pressure shall be no less than 20% and no more than 30% of the standard inflation pressure, and the first time shall be no less than 1 hour.

[0031] The second pressure shall be no less than 60% and no more than 80% of the standard inflation pressure, and the second time shall be no less than 2 hours.

[0032] The third pressure shall be no less than 120% of the standard inflation pressure and no more than the maximum sidewall inflation pressure (MAX PRESS), and the third time shall be no less than 20 hours.

[0033] In some implementations, the method of simulating road driving under load is as follows:

[0034] Under the third pressure, the applied load force shall not be less than 140% and not greater than 160% of the maximum tire load;

[0035] The simulated speed is not less than 95 km / h and not more than 110 km / h;

[0036] The simulated driving time is 80-100 hours.

[0037] In some implementations, the first and second silencing foams are alternately arranged.

[0038] In some embodiments, there are two of each of the first and second sound-absorbing cotton, arranged in a cross-shaped staggered structure.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] 1. By combining the long axis length of the tire contact patch and the stress analysis of the sound-absorbing cotton, the lengths of the first and second sound-absorbing cotton are determined. When the length of the first sound-absorbing cotton is greater than the long axis length of the tire contact patch, the two ends of the first sound-absorbing cotton are subjected to the maximum instantaneous impact force and the maximum recovery deformation force, respectively, thus verifying the adhesion performance between the ends of the sound-absorbing cotton and the inner layer of the tire. When the length of the second sound-absorbing cotton is less than the long axis length of the tire contact patch, the second sound-absorbing cotton is not only located in the maximum deformation area, but also experiences the maximum normal stress and shear stress, making it prone to separation from the tire. This design can effectively verify the overall adhesion performance between the sound-absorbing cotton and the inner layer of the tire.

[0041] 2. Inflation is performed in stages to allow the sound-absorbing foam to better adapt to the circumferential stretching of the tire, thereby improving the accuracy of the test results.

[0042] 3. To infer the adhesion between the sound-absorbing foam and the inner layer of the tire under extreme conditions, we considered the two most critical factors: load and speed. We deduced the load range and speed range that have the greatest impact on it, and used this as the standard for simulation tests. This allows us to more effectively judge the adhesion performance between the sound-absorbing foam and the inner layer of the tire. Attached Figure Description

[0043] The accompanying drawings, which are provided to further illustrate the invention and constitute a part of this invention, are illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention.

[0044] Figure 1 This is a schematic diagram showing the distribution of the first and second sound-absorbing cotton of the present invention.

[0045] Figure 2 This is a schematic diagram showing the relationship between the long axis of the tire contact patch and the tire radius and tire sinkage of the present invention.

[0046] Figure 3 This is a schematic diagram of the force applied to the second sound-absorbing foam of the present invention.

[0047] Figure 4 This is a schematic diagram of the force applied to the first sound-absorbing cotton of the present invention.

[0048] Figure 5 The present invention relates to the surface structure of noise-reducing foam for tires of specification 235 / 45R18 when subjected to staged inflation at 60 kPa.

[0049] Figure 6 The present invention relates to the surface structure of noise-reducing foam for tires of specification 235 / 45R18 when subjected to staged inflation at 180 kPa.

[0050] Figure 7 The present invention relates to the surface structure of noise-reducing foam for tires of specification 235 / 45R18 when the tire is pressurized to 300 kPa in stages.

[0051] Figure 8 The surface structure of the noise-reducing cotton is provided for a tire specification of 235 / 45R18 when the instantaneous inflation pressure is 300 kPa.

[0052] Figure 9 The graph shows the variation of the maximum ground contact width (MW) during a load test on a tire with a load index of 89 according to the present invention.

[0053] Figure 10 The graph shows the variation of the maximum ground contact width (MW) during a load test on a tire with a load index of 94 according to the present invention.

[0054] Figure 11 The graph shows the variation of the maximum ground contact width (MW) during a load test on a tire with a load index of 97 according to the present invention.

[0055] Figure 12 The table shows the physical properties of five different types of sound-absorbing foam.

[0056] Figure 13 for Figure 11 Noise curves of five different types of sound-absorbing cotton in the frequency range of 190Hz to 240Hz at test speeds of 60km / h to 120km / h.

[0057] Attached image description: First silencing foam 1, Second silencing foam 2. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments provided by this invention without inventive effort are within the scope of protection of this invention.

[0059] Obviously, the accompanying drawings described below are merely some examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, modifications to design, manufacturing, or production based on the technical content disclosed in this invention are merely conventional technical means and should not be construed as insufficient disclosure of the present invention.

[0060] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention may be combined with other embodiments without conflict.

[0061] This invention discloses a method for testing the adhesion performance of sound-absorbing cotton to tires, comprising the following steps:

[0062] S1. Under no-pressure conditions, the first and second sound-absorbing cotton are adhered to the inside of the tire along the tire's direction of movement; wherein, the length of the first sound-absorbing cotton is greater than the long axis of the tire contact patch; and the length of the second sound-absorbing cotton is less than the long axis of the tire contact patch.

[0063] S2. Perform staged inflation of the tire interior to make the first and second sound-absorbing cotton adhere to the tire interior.

[0064] S3. Perform load simulation road driving on the inflated tires.

[0065] In some implementations, the length of the major axis of the tire contact patch is calculated as follows:

[0066] L = 2 * R * sinα (Formula 1);

[0067] α=arccos((Ra) / R) (Formula 2);

[0068] a = k * b (Formula 3);

[0069] in,

[0070] L represents the length of the major axis of the tire contact patch, in millimeters;

[0071] R is the tire radius, in millimeters;

[0072] 'a' represents the tire deflection, in millimeters.

[0073] k is the tire sink rate, 0.2≦k≦0.3;

[0074] b represents the tire end face height, in millimeters;

[0075] The lengths of the first and second sound-absorbing foams are calculated as follows:

[0076] The length of the first silencing foam is L+2*c, in millimeters, and k=0.3;

[0077] The length of the second sound-silencing foam is L-2*c, in millimeters, and k = 0.2;

[0078] c represents the thickness of the sound-absorbing foam, in millimeters.

[0079] In some implementations, the staged pressurization method is as follows:

[0080] A1. Park immediately after inflating the tire to its first pressure;

[0081] A2. After inflating the tire to the second pressure, park for the second time;

[0082] A3. After inflating the tire to the third pressure, leave it for the third time.

[0083] A4. Adjust the tire pressure to the third pressure setting;

[0084] in,

[0085] The first pressure shall be no less than 20% and no more than 30% of the standard inflation pressure, and the first time shall be no less than 1 hour.

[0086] The second pressure shall be no less than 60% and no more than 80% of the standard inflation pressure, and the second time shall be no less than 2 hours.

[0087] The third pressure shall be no less than 120% of the standard inflation pressure and no more than the maximum sidewall inflation pressure (MAX PRESS), and the third time shall be no less than 20 hours.

[0088] The inflation process is illustrated using a tire specification of 235 / 45R18 and a standard inflation pressure of 250 kPa as an example.

[0089] First, the tire was inflated to a pressure of 60 kPa and then left to stand for one hour. Since the sound-absorbing foam was attached to the tire in a non-inflated state, after the initial inflation, the tire's radial stretch was 3 mm compared to the tire mold diameter, with minimal crown deformation. Simultaneously, inflation applied a certain force to the sound-absorbing foam. Under 100x magnification microscopy, the surface of the sound-absorbing foam remained intact and undamaged. Figure 5 The circular structure is free of tears.

[0090] The advantages of this design are that it not only avoids tearing gaps in the contact area between the sound-absorbing foam and the tire due to excessive radial stretching of the tire, which could lead to errors in test results, but also that after the initial pressure holding, the sound-absorbing foam can better adapt to the circumferential stretching of the tire, improving the accuracy of test results.

[0091] Then, the tire was inflated a second time to a pressure of 180 kPa, and left to stand for a second time for 2 hours. After the second inflation, the tire's radial stretch was 7 mm compared to the diameter under the first pressure. Under 100x magnification microscopy, the surface of the sound-absorbing foam was found to be intact and undamaged. Figure 6 The circular structure is free of tears.

[0092] This design allows the sound-absorbing foam to further adapt to the circumferential stretching of the tire under high inflation pressure without being damaged.

[0093] Finally, the tire was inflated a third time, with the third pressure being the maximum sidewall pressure of 300 kPa, and the tire was left to stand for at least 20 hours. After the third inflation, compared to the diameter under the second pressure, the radial elongation of the tire was less than 1 mm, and the deformation of the tread area and the sound-absorbing foam was minimal. Under 100x magnification microscopy, the surface of the sound-absorbing foam was intact and undamaged. Figure 7 The circular structure is free of tears.

[0094] Compared to the staged pressurization method, Figure 8 The attached diagram shows the surface structure of the sound-absorbing foam when the instantaneous pressing pressure is 300 kPa. As can be seen from the diagram, the sound-absorbing foam exhibits a torn structure. Therefore, instantaneous pressing will damage the surface structure of the sound-absorbing foam.

[0095] When a tire reaches 120% of its standard inflation pressure but does not exceed the maximum sidewall inflation pressure (MAX PRESS), it is close to or has reached the maximum sidewall inflation pressure. Therefore, once this inflation pressure range is reached, its elongation is also close to or reaches its maximum value. Consequently, within this pressure range, the circumferential elongation of the sound-absorbing foam adhered to the inside of the tire is close to or reaches its maximum. Therefore, using the third pressure reading as the internal tire pressure for subsequent simulated road conditions provides a more accurate assessment of the sound-absorbing foam's limits.

[0096] In some implementations, the method of simulating road driving under load is as follows:

[0097] Under the third pressure, the applied load force shall not be less than 140% and not greater than 160% of the maximum tire load;

[0098] The simulated speed is not less than 95 km / h and not more than 110 km / h;

[0099] The simulated driving time is 80-100 hours.

[0100] As the load on the tire increases, the deformation of the tire crown against the ground gradually increases. However, once it reaches a certain level, due to the inherent limitations of the material itself, the rate of change of its deformation will gradually decrease.

[0101] To determine the limit range of tire deformation load conditions, several groups of tires with different load indices were selected for simulated load tests.

[0102] like Figure 9 Load tests were conducted on tires with a load index of 89. A load index of 89 corresponds to a maximum load capacity of 5684 N. By applying loads ranging from 1000 N to 10000 N to the tires, the maximum ground contact width (MW) showed the smallest rate of change within the range of 8000 N to 9000 N, at which point the load rate was 140% to 160%.

[0103] like Figure 10 Load tests were conducted on tires with a load index of 94. A load index of 94 corresponds to a maximum load capacity of 6566 N. By applying loads ranging from 1000 N to 11000 N to the tires, the maximum ground contact width (MW) showed the smallest rate of change within the range of 9000 N to 10500 N, at which point the load rate was 140% to 160%.

[0104] like Figure 11 Load tests were conducted on tires with a load index of 97. A load index of 97 corresponds to a maximum load capacity of 7154 N. By applying loads ranging from 1000 N to 12000 N to the tires, the maximum ground contact width (MW) showed the smallest rate of change within the range of 9000 N to 10500 N, at which point the load rate was 140% to 160%.

[0105] pass Figures 9-11 Load tests were conducted on tires with different load indices. The test curves revealed that the maximum contact patch width (MW) gradually increases with increasing load, with the smallest rate of change occurring within the 140%–160% load range, approaching its limit. Therefore, the applied load force should be no less than 140% and no more than 160% of the tire's maximum load.

[0106] In addition, the airflow inside the tire due to tire rotation speed must be considered. At high speeds, the air inside the tire exerts a strong impact on the sound-absorbing foam, generating noise. Therefore, by testing the noise generated by sound-absorbing foam of different materials at different speeds, it is possible to deduce the speed range at which the impact on the sound-absorbing foam is greater, thus making the limit test of the sound-absorbing foam more accurate.

[0107] like Figure 12 Five different types of sound-absorbing cotton were used, and the physical properties of the cotton were described, such as... Figure 13 The above five types of sound-absorbing foam have noise results in the frequency range of 190Hz to 240Hz at test speeds of 60km / h to 120km / h. As can be seen from the attached figure, the cavity noise reaches its maximum value when the tire speed reaches 100±5km / h, thus having the greatest impact on the sound-absorbing foam.

[0108] The following is a detailed description of one specific implementation method:

[0109] like Figure 1 As shown, two first sound-absorbing cotton 1s and two second sound-absorbing cotton 2s are glued inside the tire and arranged in an interlaced cross structure.

[0110] The length of the first sound-absorbing cotton is L + 2*c, and k = 0.3 is selected for calculation; the length of the second sound-absorbing cotton is L - 2*c, and k = 0.2 is selected for calculation; the conventional range of the tire sinking rate k is 0.2 ≤ k ≤ 0.3; since the first sound-absorbing cotton is mainly used to test the adhesion performance between the end of the sound-absorbing cotton and the inside of the tire, k is taken as the maximum value; since the second sound-absorbing cotton is mainly used to test the adhesion performance between the entire part of the sound-absorbing cotton and the inside of the tire, k is taken as the minimum value.

[0111] like Figure 3 and Figure 4 As shown, the length of the first sound-absorbing cotton 1 is greater than the long axis of the tire contact patch. The two ends of the first sound-absorbing cotton 1 are subjected to the maximum instantaneous impact force and the maximum recovery deformation force, respectively, thereby verifying the adhesion performance between the ends of the sound-absorbing cotton and the inner layer of the tire. When the length of the second sound-absorbing cotton 2 is less than the long axis of the tire contact patch, the second sound-absorbing cotton 2 is not only located in the maximum deformation area, but also experiences the maximum normal stress and shear stress, which makes it easy for the sound-absorbing cotton to separate from the tire. This design can effectively verify the adhesion performance between the sound-absorbing cotton as a whole and the inner layer of the tire.

[0112] Therefore, by using the above arrangement, the adhesion performance test of the ends of the sound-absorbing cotton and the whole can be completed in one test, and the two parts do not affect each other, thus improving the testing efficiency.

[0113] After the first and second sound-absorbing cotton 1 and the second sound-absorbing cotton 2 are bonded together, a three-stage inflation and waiting process is carried out. In the first stage, inflation at a relatively low pressure applies a certain force to the first and second sound-absorbing cotton 1 and the second sound-absorbing cotton 2, which improves their bonding effect and allows the sound-absorbing cotton to adapt to the stretching caused by the tire inflation process. In the second stage, inflation at a moderate pressure further adapts to the circumferential stretching of the tire under high inflation pressure. In the third stage, inflation at a relatively high pressure brings the circumferential stretching of the sound-absorbing cotton close to its limit, thereby improving the accuracy of subsequent testing.

[0114] After completing the above inflation and corresponding waiting process, under the pressure range of the third stage, the applied load force shall not be less than 140% and not more than 160% of the maximum tire load; the simulated speed shall not be less than 95 km / h and not more than 110 km / h; and the simulated driving time shall be 80-100 hours.

[0115] After completing the above experimental steps, neither the first sound-absorbing cotton 1 nor the second sound-absorbing cotton 2 separated from the inside of the tire, indicating that the adhesion performance between the sound-absorbing cotton and the tire is excellent. Since the above test steps combine many extreme ranges, the test results are more representative. The tire that passes the above test has more reliable and representative adhesion performance with the sound-absorbing cotton.

[0116] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for testing the adhesion performance of noise-reducing foam to tires, characterized in that, Includes the following steps: S1. Under no-pressure conditions, the first and second sound-absorbing cotton are adhered to the inside of the tire along the tire's direction of movement; wherein, the length of the first sound-absorbing cotton is greater than the long axis of the tire contact patch; and the length of the second sound-absorbing cotton is less than the long axis of the tire contact patch. S2. Perform staged inflation of the tire interior to make the first and second sound-absorbing cotton adhere to the tire interior. S3. Perform load simulation road driving on the inflated tires; The calculation method for the major axis length of the tire contact patch is as follows: L = 2 * R * sinα (Formula 1); α=arccos((Ra) / R) (Formula 2); a = k * b (Formula 3); in, L represents the length of the major axis of the tire contact patch, in millimeters; R is the tire radius, in millimeters; 'a' represents the tire deflection, in millimeters. k is the tire sink rate, 0.2≦k≦0.3; b represents the tire end face height, in millimeters; The lengths of the first and second sound-absorbing foams are calculated as follows: The length of the first sound-silencing foam is L+2*c, in millimeters; The length of the second sound-silencing foam is L-2*c, in millimeters; c represents the thickness of the sound-absorbing foam, in millimeters; The staged pressurization method is as follows: A1. Park immediately after inflating the tire to its first pressure; A2. After inflating the tire to the second pressure, park for the second time; A3. After inflating the tire to the third pressure, leave it for the third time. A4. Adjust the tire pressure to the third pressure setting; in, The first pressure shall be no less than 20% and no more than 30% of the standard inflation pressure, and the first time shall be no less than 1 hour. The second pressure shall be no less than 60% and no more than 80% of the standard inflation pressure, and the second time shall be no less than 2 hours. The third pressure shall be no less than 120% of the standard inflation pressure and no more than the maximum sidewall inflation pressure MAX PRESS, and the third time shall be no less than 20 hours.

2. The test method according to claim 1, characterized in that, When calculating the length of the first sound-absorbing foam, k=0.3; when calculating the length of the second sound-absorbing foam, k=0.

2.

3. The test method according to claim 1, characterized in that, The method for simulating road driving under load is as follows: Under the third pressure, the applied load force shall not be less than 140% and not greater than 160% of the tire's maximum load; The simulated speed is not less than 95 km / h and not more than 110 km / h; The simulated driving time is 80-100 hours.

4. The test method according to claim 1, characterized in that, The first and second silencing foams are alternately installed.

5. The test method according to claim 4, characterized in that, There are two of each of the first and second sound-absorbing foams, arranged in a cross-shaped staggered structure.

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