A method for calibrating the lower limit of the sewing stitch length of the weakened line of the seat cover

Abstract

The present invention relates to a method for calibrating the lower limit of the sewing needle distance of the weakened line of a seat cover, comprising the following steps: step 1, preliminary setting of the lower limit of the sewing needle distance of the weakened line of the seat cover; step 2, production of a first seat test sample; step 3, low temperature and low limit working condition side airbag detonation test; step 4, production of a second seat test sample; step 5, normal temperature and normal working condition side airbag detonation test, to obtain the calibration value of the lower limit of the sewing needle distance of the weakened line of the seat cover. The present invention can efficiently realize the calibration of the lower limit of the sewing needle distance of the weakened line of the seat cover.

Description

Technical Field

[0001] The invention relates to an automobile, and in particular to a method for calibrating a lower limit of sewing needle length of a weakened line of a seat cover. Background Art

[0002] With the development of society and the continuous progress of science and technology, people pay more and more attention to automobile safety. Among them, the requirements for occupant protection in GB20071 automobile side collision, occupant protection in C-NCAP and occupant safety index in C-IASI are getting higher and higher. The corresponding side collision requirements all include the performance requirements for the detonation of seat side airbags. It can be seen that seats play a pivotal role in side collision safety. The sewing stitch length requirements for the weakened lines of seat covers in the industry are general requirements, which are 50mm / 10 needles-60mm / 10 needles, and the range of sewing stitch lengths is relatively wide; because the sewing stitch length of the weakened lines of seat covers has an impact on the detonation of side airbags, in order to improve the safety dissipation of side collisions, it is necessary to more accurately calibrate the sewing stitch length of the weakened lines of seat covers, but there is no method for calibrating the sewing stitch length of the weakened lines of seat covers in the prior art. Summary of the invention

[0003] The purpose of the present invention is to provide a method for calibrating the lower limit of the sewing stitch length of the weakened line of the seat cover, so as to realize the calibration of the lower limit of the sewing stitch length of the point-explosion weakened line of the seat cover.

[0004] The method for calibrating the lower limit of the sewing stitch length of the weakened line of a seat cover according to the present invention comprises the following steps:

[0005] Step 1: Preliminary setting of the lower limit of the sewing stitch length of the seat cover weakening line.

[0006] Preliminarily set the initial value of the lower limit of the sewing stitch length of the weakened line of the seat cover;

[0007] Step 2: Production of the first seat test sample.

[0008] A first seat cover sample is manufactured based on an initial value of the lower limit of the sewing stitch length of the weakened line, and a side airbag equipped with a low-limit side airbag generator and the first seat cover sample are assembled to a vehicle seat to manufacture a first seat test sample;

[0009] Step 3: Low temperature and low limit working condition side airbag detonation test,

[0010] Using the first seat test sample prepared in step 2, a low temperature and low limit working condition side airbag detonation test is performed in an environment of -37°C to -33°C;

[0011] If the test result of the low temperature and low limit working condition side airbag detonation test does not meet the requirements, return to step 2, adjust the value of the lower limit of the sewing stitch length of the weakening line, and update the first seat test sample based on the adjusted lower limit of the sewing stitch length of the weakening line until the test result of the low temperature and low limit working condition side airbag detonation test meets the requirements;

[0012] If the test result of the low temperature and low limit working condition side airbag detonation test meets the requirements, the value of the lower limit of the sewing stitch length of the weakened line corresponding to the first seat cover sample in the test shall be recorded as the updated value of the lower limit of the sewing stitch length of the weakened line;

[0013] Step 4: Production of the second seat test sample.

[0014] A second seat cover sample is manufactured based on the updated value of the lower limit of the sewing stitch length of the weakened line, and a side airbag equipped with a conventional side airbag generator and the second seat cover sample are assembled to a vehicle seat to manufacture a second seat test sample;

[0015] Step 5: Normal temperature and normal working condition side airbag detonation test,

[0016] Using the second seat test sample prepared in step 4, conduct a normal temperature and normal working condition side airbag detonation test in an environment of 21° C. to 25° C.;

[0017] If the test result of the normal temperature conventional working condition side airbag detonation test does not meet the requirements, return to step 4, adjust the value of the lower limit of the sewing stitch length of the weakening line, and update the second seat test sample based on the adjusted lower limit of the sewing stitch length of the weakening line until the test result of the normal temperature conventional working condition side airbag detonation test meets the requirements;

[0018] If the test results of the side airbag detonation test under normal temperature and conventional working conditions meet the requirements, the value of the lower limit of the sewing stitch length of the weakened line corresponding to the second seat cover sample in this test shall be recorded as the calibration value of the lower limit of the sewing stitch length of the weakened line.

[0019] Optionally, the step one includes: dividing the seat cover weakening line into an initial sewing section, a main bursting section and a finishing sewing section which are arranged in sequence, and setting an initial value of the lower limit of the sewing stitch length of the main bursting section according to the sewing stitch length rule of 50mm / 10 stitches.

[0020] Optionally, in step three, the lower limit of the sewing stitch length of the weakening line is adjusted by increasing it by 0.2 mm / stitch each time.

[0021] Optionally, in step five, the lower limit of the sewing stitch length of the weakening line is adjusted by increasing the value by 0.2 mm / stitch each time.

[0022] Optionally, in step three, if the side airbag whitening moment of the low-temperature and low-limit operating condition side airbag detonation test meets the design requirements, the test results are judged to meet the requirements, otherwise the test results are judged to not meet the requirements.

[0023] Optionally, in step five, if the side airbag whitening moment of the side airbag detonation test under normal temperature and conventional operating conditions meets the design requirements, the test results are judged to meet the requirements, otherwise the test results are judged to not meet the requirements.

[0024] The present invention can efficiently realize the calibration of the lower limit of the sewing needle distance of the weakened line of the seat cover. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a flow chart of the method for calibrating the lower limit of the sewing stitch length of the seat cover weakening line described in the specific implementation manner;

[0026] Figure 2 is a segmented schematic diagram of the seat cover weakening line described in the specific implementation manner;

[0027] Figure 3 It is a schematic diagram of the sewing equipment identification point described in the specific implementation manner. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings.

[0029] like Figure 1 A method for calibrating the lower limit of the sewing stitch length of a seat cover weakening line shown in the figure comprises the following steps:

[0030] Step 1: Preliminary setting of the lower limit of the sewing stitch length of the seat cover weakening line

[0031] The initial value of the lower limit of the sewing stitch length of the weakened line of the seat cover is preliminarily set. Specifically, the weakened line of the seat cover is divided into an initial sewing section, a main blasting section and a finishing sewing section, which are set in sequence. The sewing stitch length of the initial sewing section and the finishing sewing section is smaller than that of the main blasting section. In specific implementation, the initial value of the lower limit of the sewing stitch length of the main blasting section can be set according to the sewing stitch length rule of 50mm / 10 stitches. During the detonation process of the side airbag, the main blasting section is mainly used to ensure the smooth deployment of the side airbag. Therefore, in actual implementation, the method for calibrating the lower limit of the sewing stitch length of the weakened line of the seat cover is usually to calibrate the lower limit of the sewing stitch length of the main blasting section, which can more accurately calibrate the lower limit of the sewing stitch length of the weakened line of the seat cover.

[0032] Taking a specific project as an example, Figure 2As shown in the figure, according to the seat cover design scheme and the side airbag deployment diagram, the total design length of the seat cover weakening line is determined to be L, the length of the initial sewing section ab is L1, the length of the main explosion section bc is L2, and the length of the final sewing section cd is L3. The sum of L1, L2 and L3 is equal to L. Figure 3 As shown in the figure, during the production process of the seat cover, the two points b and c on the seat cover should be used as sewing equipment identification points to facilitate accurate identification by the sewing equipment sensor. In the automotive industry, the design standard for sewing the weakened line of the seat cover is usually: the lower limit of the sewing needle distance of the weakened line is 50mm / 10 needles, and the upper limit of the sewing needle distance of the weakened line is 60mm / 10 needles; therefore, the initial value of the lower limit of the sewing needle distance of the main blasting section is set to 5mm / needle, and the upper and lower limits of the sewing tension are determined according to the appearance requirements of the seat cover and the type of decorative line to determine the preliminary parameters of the weakened line.

[0033] Step 2: Preparation of the first seat test sample

[0034] Based on the preliminary parameters of the weakening line (including the initial value of the lower limit of the sewing stitch length of the main blasting section), the first seat cover sample is made, and the side airbag equipped with a low-limit side airbag generator and the first seat cover sample are assembled to the automobile seat to make the first seat test sample; in the specific implementation, the side airbag equipped with the low-limit side airbag generator is first assembled on the seat frame, and then the foam and the first seat cover sample are assembled to make the first seat test sample.

[0035] Step 3: Low temperature and low limit working condition side airbag detonation test

[0036] Using the first seat test sample prepared in step 2, a low-temperature low-limit working condition side airbag detonation test is performed in an environment of -37°C to -33°C; if the test result of the low-temperature low-limit working condition side airbag detonation test does not meet the requirements, return to step 2, adjust the value of the lower limit of the sewing needle distance of the main bursting section, and adjust the value of the lower limit of the sewing needle distance of the main bursting section by increasing it by 0.2mm / needle each time, and update the first seat test sample based on the adjusted lower limit of the sewing needle distance of the main bursting section until the test result of the low-temperature low-limit working condition side airbag detonation test meets the requirements; if the test result of the low-temperature low-limit working condition side airbag detonation test meets the requirements, record the value of the lower limit of the sewing needle distance of the main bursting section corresponding to the first seat cover sample in this test as the updated value of the lower limit of the sewing needle distance of the main bursting section;

[0037] Specifically, when judging whether the test result of the low temperature and low limit working condition side airbag detonation test meets the requirements, if the side airbag whitening moment of the low temperature and low limit working condition side airbag detonation test meets the design requirements, then the test result is judged to meet the requirements; if the side airbag whitening moment of the low temperature and low limit working condition side airbag detonation test does not meet the design requirements, then the test result is judged to not meet the requirements. In other embodiments, the indicators for judging whether the test result of the low temperature and low limit working condition side airbag detonation test meets the requirements may also include: whether the detonation splash meets the design requirements, and whether the side airbag deployment degree meets the design requirements.

[0038] Step 4: Preparation of the second seat test sample

[0039] A second seat cover sample is manufactured based on the updated value of the lower limit of the sewing stitch length of the main burst section, and a side airbag equipped with a conventional side airbag generator and the second seat cover sample are assembled to a vehicle seat to manufacture a second seat test sample;

[0040] Step 5: Side airbag detonation test under normal temperature and normal working conditions

[0041] Using the second seat test sample prepared in step 4, conduct a normal temperature and normal working condition side airbag detonation test in an environment of 21° C. to 25° C.;

[0042] If the test result of the normal temperature conventional working condition side airbag detonation test does not meet the requirements, return to step 4, adjust the value of the lower limit of the sewing needle distance of the main explosion section, and adjust the value of the lower limit of the sewing needle distance of the main explosion section by increasing it by 0.2 mm / needle each time, and update the second seat test sample based on the adjusted lower limit of the sewing needle distance of the main explosion section until the test result of the normal temperature conventional working condition side airbag detonation test meets the requirements;

[0043] If the test result of the normal temperature conventional working condition side airbag detonation test meets the requirements, the value of the lower limit of the sewing needle distance of the main bursting section corresponding to the second seat cover sample in this test shall be recorded as the calibration value of the lower limit of the sewing needle distance of the main bursting section;

[0044] Specifically, when determining whether the test result of the normal temperature and normal working condition side airbag detonation test meets the requirements, if the side airbag whitening moment of the normal temperature and normal working condition side airbag detonation test meets the design requirements, then the test result is determined to meet the requirements; if the side airbag whitening moment of the normal temperature and normal working condition side airbag detonation test does not meet the design requirements, then the test result is determined to not meet the requirements. In other embodiments, the indicators for determining whether the test result of the normal temperature and normal working condition side airbag detonation test meets the requirements may also include: whether the detonation splash meets the design requirements, and whether the side airbag deployment degree meets the design requirements.

[0045] After obtaining the calibration value of the lower limit of the sewing stitch length of the main bursting section through step five, the calibration value of the lower limit of the sewing stitch length of the main bursting section can be used as the lower limit value of the sewing stitch length of the weakening line during the production of the seat cover, and the upper limit value of the sewing stitch length of the weakening line can be set to 6mm / needle. The weakening line of the seat cover can be designed according to the lower limit value and upper limit value of the sewing stitch length of the weakening line.

[0046] In the above-mentioned method for calibrating the lower limit of the sewing stitch length of the weakened line of the seat cover, a low-temperature and low-limit working condition side airbag detonation test is first carried out. If the side airbag can be deployed normally in the low-temperature and low-limit working condition side airbag detonation test, the side airbag can be deployed under other working conditions; then a normal temperature and conventional working condition side airbag detonation test is carried out. If the whitening moment of the side airbag meets the design requirements, the calibration value of the lower limit of the sewing stitch length can be determined. Experimental verification is carried out using other test working conditions. The calibration value of the lower limit of the sewing stitch length of the weakened line determined after the side airbag detonation test under the above two working conditions can successfully pass the verification of the side airbag detonation test under other test working conditions. In other words, the present invention reasonably selects the test working conditions and improves the efficiency of calibration.

[0047] When conducting a side airbag detonation test, you can refer to the equipment requirements in a universal seat side airbag static deployment test bench disclosed in the patent application with application number CN201922236783.4, install the seat test sample on the seat side airbag static deployment test bench, and conduct a side airbag detonation test.

[0048] The seat side airbag is composed of a gunpowder generator and an airbag. There are generally three types of gunpowder generators used for ignition tests, namely, conventional side airbag generators, high-limit side airbag generators and low-limit side airbag generators. The pressure curve of the high-limit side airbag generator is higher than the upper limit of the pressure curve of the conventional side airbag generator, and the pressure curve of the low-limit side airbag generator is lower than the lower limit of the pressure curve of the conventional side airbag generator.

[0049] The white-out time of the side airbag detonation refers to the moment when the airbag is quickly filled after the gunpowder is detonated and exposed from the seat cover. Each OEM will decompose the side airbag white-out time requirement into the system-level test according to the vehicle side impact calibration. The seat side airbag detonation test conditions are matrix tested according to the temperature and side airbag generator type. The temperature is divided into high temperature, normal temperature and low temperature, among which: the low temperature range is -37℃ to -33℃, including -37℃ and -33℃; the normal temperature range is 21℃ to 25℃, including 21℃ to 25℃; the high temperature range is 83℃ to 87℃, including 83℃ to 87℃.

[0050] High temperature, normal temperature and low temperature are respectively combined with conventional side airbag generators, high-limit side airbag generators and low-limit side airbag generators to form a variety of test conditions. In this application, only two of the test conditions are used to calibrate the lower limit of the sewing stitch length.

[0051] The method for calibrating the lower limit of the sewing stitch length of the weakened line of the seat cover proposed in this application is simple and reliable to operate, which is conducive to improving the one-time pass rate of the seat side airbag detonation, and is conducive to accurately designing production parameters, and helping to achieve the performance indicators of the seat side airbag detonation. This method also fills the gap in how the industry formulates the sewing stitch length of the weakened line of the seat cover, improves the robustness of the seat product design, avoids the risk of seat side airbag deployment failure caused by fluctuations in the seat cover production process, and reduces the incidence of after-sales problems of the whole vehicle.

Claims

1. A method for calibrating the lower limit of the sewing stitch length of the weakened line of a seat cover, characterized in that: The following steps are involved: Step 1: Preliminary setting of the lower limit of the sewing stitch length of the seat cover weakening line. Preliminarily set the initial value of the lower limit of the sewing stitch length of the weakened line of the seat cover; Step 2: Production of the first seat test sample. A first seat cover sample is manufactured based on an initial value of the lower limit of the sewing stitch length of the weakened line, and a side airbag equipped with a low-limit side airbag generator and the first seat cover sample are assembled to a vehicle seat to manufacture a first seat test sample; Step 3: Low temperature and low limit working condition side airbag detonation test, Using the first seat test sample prepared in step 2, a low temperature and low limit working condition side airbag detonation test is performed in an environment of -37°C to -33°C; If the test result of the low temperature and low limit working condition side airbag detonation test does not meet the requirements, return to step 2, adjust the value of the lower limit of the sewing stitch length of the weakening line, and update the first seat test sample based on the adjusted lower limit of the sewing stitch length of the weakening line until the test result of the low temperature and low limit working condition side airbag detonation test meets the requirements; If the test result of the low temperature and low limit working condition side airbag detonation test meets the requirements, the value of the lower limit of the sewing stitch length of the weakened line corresponding to the first seat cover sample in the test shall be recorded as the updated value of the lower limit of the sewing stitch length of the weakened line; Step 4: Production of the second seat test sample. A second seat cover sample is manufactured based on the updated value of the lower limit of the sewing stitch length of the weakened line, and a side airbag equipped with a conventional side airbag generator and the second seat cover sample are assembled to a vehicle seat to manufacture a second seat test sample; Step 5: Normal temperature and normal working condition side airbag detonation test, Using the second seat test sample prepared in step 4, conduct a normal temperature and normal working condition side airbag detonation test in an environment of 21° C. to 25° C.; If the test result of the normal temperature conventional working condition side airbag detonation test does not meet the requirements, return to step 4, adjust the value of the lower limit of the sewing stitch length of the weakening line, and update the second seat test sample based on the adjusted lower limit of the sewing stitch length of the weakening line until the test result of the normal temperature conventional working condition side airbag detonation test meets the requirements; If the test result of the normal temperature conventional working condition side airbag detonation test meets the requirements, the value of the lower limit of the sewing stitch length of the weakened line corresponding to the second seat cover sample in this test shall be recorded as the calibration value of the lower limit of the sewing stitch length of the weakened line; In the step 3, if the side airbag whitening moment, the explosion splashes and the side airbag deployment degree of the low temperature and low limit working condition side airbag explosion test meet the design requirements, then the test result is judged to meet the requirements, otherwise, the test result is judged to not meet the requirements; In step five, if the side airbag whitening moment of the side airbag detonation test under normal temperature and conventional working conditions meets the design requirements, then the test result is judged to meet the requirements, otherwise, the test result is judged to not meet the requirements.

2. The method for calibrating the lower limit of the sewing stitch length of the seat cover weakening line according to claim 1, characterized in that: The step 1 comprises: dividing the seat cover weakening line into an initial sewing section, a main bursting section and a finishing sewing section which are arranged in sequence, and setting an initial value of the lower limit of the sewing stitch length of the main bursting section according to the sewing stitch length rule of 50 mm / 10 stitches.

3. The method for calibrating the lower limit of the sewing stitch length of the seat cover weakening line according to claim 1, characterized in that: In the step 3, the lower limit of the sewing stitch length of the weakened line is adjusted by increasing the value by 0.2 mm / stitch each time.

4. The method for calibrating the lower limit of the sewing stitch length of the seat cover weakening line according to claim 1, characterized in that: In the step 5, the lower limit of the sewing stitch length of the weakened line is adjusted by increasing the value by 0.2 mm / stitch each time.

Images