阅读说明：本技术 一种汽车轮胎平点试验方法、数据处理方法和设备 (Automobile tire flat spot test method, data processing method and equipment ) 是由 张文清 吕剑 吴健 王杰 柯诗杭 于 2021-06-15 设计创作，主要内容包括：本发明属于轮胎检测领域,涉及一种汽车轮胎平点试验方法、数据处理方法和设备。该方法通过获得平点前高速均匀性和平点后的高速均匀性数据,然后可以通过再进行数据分析和计算获得平点数据,可以用来评估一条轮胎是否符合组件平点要求,也可用来帮助诊断车辆的振动问题。(The invention belongs to the field of tire detection, and relates to an automobile tire flat spot test method, a data processing method and data processing equipment. The method can be used for evaluating whether a tire meets the flat point requirement of a component or not and helping to diagnose the vibration problem of a vehicle by obtaining high-speed uniformity data before flat point and high-speed uniformity data after flat point and then obtaining flat point data through data analysis and calculation.)

1. A flat spot test method for automobile tires is characterized by comprising the following steps:

1) tire installation and parking: selecting high-precision rims meeting the standard specification, sequentially mounting the rims on a test tire, and stopping the tire at the ambient temperature of a test chamber for at least 3 hours;

2) tire imbalance measurement and balancing: mounting the parked tire and rim assembly on a tire high-speed uniformity testing machine for unbalance measurement; balancing and balancing the tire and rim assembly according to the unbalance measurement result until the static unbalance mass is reduced to be within 5 g;

3) low-speed uniformity measurement: marking a zero-degree reference mark on a tire, rim and wheel assembly, performing a low-speed uniformity test to obtain a high point position of an H1RFV, positioning a low point of the H1RFV by moving the high point position of the H1RFV by 180 degrees, and marking the low point position of the H1RFV on the tire;

4) high speed uniformity test before leveling: carrying out high-speed uniformity test, starting to achieve a steady-state test condition, continuously carrying out data acquisition, and taking the acquired data as initial high-speed uniformity data of the tire;

5) flat spot generation: placing the tire and rim assembly on a flat point loading system which reaches the test temperature within 10min, and keeping the tire and rim assembly loaded for a specified time under the test load and the test temperature, wherein the flat point ballast positions are as follows: h1RFV low point, the load control method is load control;

6) high-speed uniformity test after leveling: and (3) performing a high-speed uniformity test under the condition that the position of the valve is at a phase angle of 0, and the synchronous step 4), and taking the acquired data as high-speed uniformity data after the tire is flattened.

2. The flat spot test method for the automobile tire according to claim 1, wherein step 3) warms the tire for 1min under the following air pressure and load conditions at the tire rotating speed of 60r/min, and then performs the low-speed uniformity test:

sedan tires: the test air pressure is 210kPa, and the test load is the maximum load capacity multiplied by 70 percent;

light truck or commercial vehicle tire: the test air pressure is 350kPa, and the test load is the maximum load capacity multiplied by 70%.

3. The flat spot test method for the automobile tire according to claim 1, wherein the conditions of the high speed uniformity test in the step 4) are as follows:

sedan tires: the test air pressure is 210kPa, the test load is the maximum load capacity multiplied by 70 percent, and the test speed is 120 km/h;

light truck or commercial vehicle tire: the test air pressure is 350kPa, the test load is the maximum load capacity multiplied by 70 percent, and the test speed is 120 km/h.

4. The method for testing the flat spot of the automobile tire according to claim 3, wherein the step 4) is performed for 30 minutes starting when the steady state test condition is reached, the data acquisition should be performed at 30 second intervals, 8 circles of data are continuously acquired each time, and the 60 groups of data are used as the initial high speed uniformity data of the tire.

5. The flat spot testing method for automobile tires according to claim 1, characterized in that step 5) keeps loading the tire-rim assembly under the test load and the test temperature for the specified time as follows:

standard temperature test: the temperature 1 is 43.3 +/-3 ℃, and the time is 22 hours; the temperature 2 is 21 +/-3 ℃ for 2 hours;

and (3) normal temperature test: the temperature 1 is 21 +/-3 ℃ for 24 h.

6. The flat spot test method for the automobile tire according to claim 1, wherein the step 1) of assembling the tire is to uniformly coat the tire bead or the tire bead seat of the rim or both with a lubricant, and the high-precision rims meeting the standard are selected and sequentially installed on the test tire.

7. A method for processing automobile tire flat spot test data comprises the following steps:

1) carrying out average value calculation on all data acquired by any one of claims 1-6 to obtain representative 1-circle data, and taking the high-speed uniformity before and after leveling as separate data sets;

2) decomposing the radial force and the longitudinal force of the tire by using a Fourier decomposition transformation formula so as to obtain the amplitude values and the phase angles of H1RFV and H2RFV, and H1TFV and H2 TFV;

3) using H1RFV and H2RFV of each stage after flat spot generation, H1TFV and H2TFV to respectively carry out vector difference calculation with H1RFV, H2RFV, H1TFV and H2TFV of each stage before flat spot generation to obtain time-based delta H1RFV, delta H2RFV, delta H1TFV and delta H2TFV, and using polar coordinates to map; fitting is performed by exponential function decay equation (1):

（1）

wherein A represents a permanent flat spot

A + B denotes the initial flat point, t = 0;

c represents the time constant t in min.

8. An electronic device comprising a processor, a memory, and a computer program stored on the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the method of claim 7.

9. A non-transitory computer-readable carrier medium storing program instructions, the computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the method of claim 7.

Technical Field

The invention belongs to the field of tire detection, and relates to an automobile tire flat spot test method, a data processing method and data processing equipment.

Background

Flat spots refer to the tendency of the tire to change in uniformity after a period of static loading. The flat spot of the tire consists of two parts: local deformation and eccentric global deformation. The amount of flattening and attenuation depends on many factors-tire structure, material creep characteristics, tire radial load, loading time and air pressure, tire temperature and ambient temperature, tire mileage, etc.

The tire has many components, almost all of which have nylon cords under the tread. The ground contact portion is flat rather than round when the tire is installed, as is the rest, and nylon may set into this flat condition when it is in this flat condition for a long time, or sometimes when transitioning from a warm tire to a cold tire.

The flat spot test is to measure the uniformity change caused by static loading of the tire under a certain temperature condition for a certain time. It quantifies the initial and permanent effects of the flat spot. Can be used to assess whether a tire meets the flat spot requirements of the assembly and can also be used to help diagnose vibration problems in the vehicle, and quantification of the flat spot of the tire is done by measuring the high speed uniformity force or radial out-of-roundness of the tire. In recent years, the competition of the vehicle industry is intensified, tires are used as important parts which are in direct contact with the ground, and the flat spot test of the tires is required by some domestic vehicle enterprises and joint venture vehicle enterprises.

The invention discloses an automatic high and low temperature loading device for a Flat Spot test of a tire (CN206223455U), and discloses an automatic high and low temperature loading device for a Flat Spot test of the tire. The invention discloses a flat spot forming method for restraining a vehicle tire, and discloses a flat spot restraining method and a flat spot restraining device for a tire of the invention patent (CN 102803635A).

At present, the domestic standard has no unified flat spot test method, and the invention aims to provide an automobile tire flat spot test program and a data analysis method.

Disclosure of Invention

In order to solve the above technical problems, the present application aims to provide an automobile tire flat spot test method, which can be used to evaluate whether a tire meets the flat spot requirement of a component or not and also can be used to help diagnose the vibration problem of a vehicle by obtaining high-speed uniformity data before and after the flat spot and then obtaining the flat spot data by performing data analysis and calculation.

In order to achieve the above purpose, the present application adopts the following technical solutions:

a flat spot test method for an automobile tire, the method comprising the steps of:

1) tire installation and parking: selecting high-precision rims meeting the standard specification, sequentially mounting the rims on a test tire, and stopping the tire at the ambient temperature of a test chamber for at least 3 hours;

2) tire imbalance measurement and balancing: mounting the parked tire and rim assembly on a tire high-speed uniformity testing machine for unbalance measurement; balancing and balancing the tire and rim assembly according to the unbalance measurement result until the static unbalance mass is reduced to be within 5 g;

3) low-speed uniformity measurement: marking a zero-degree reference mark on a tire, rim and wheel assembly, performing a low-speed uniformity test to obtain a high point position of an H1RFV, positioning a low point of the H1RFV by moving the high point position of the H1RFV by 180 degrees, and marking the low point position of the H1RFV on the tire;

4) high speed uniformity test before leveling: carrying out high-speed uniformity test, starting to achieve a steady-state test condition, continuously carrying out data acquisition, and taking the acquired data as initial high-speed uniformity data of the tire;

5) flat spot generation: placing the tire and rim assembly on a flat point loading system which reaches the test temperature within 10min, and keeping the tire and rim assembly loaded for a specified time under the test load and the test temperature, wherein the flat point ballast positions are as follows: h1RFV low point, the load control method is load control;

6) high-speed uniformity test after leveling: and (3) performing a high-speed uniformity test under the condition that the position of the valve is at a phase angle of 0, and the synchronous step 4), and taking the acquired data as high-speed uniformity data after the tire is flattened.

As a further improvement, the step 3) warms the tire for 1min under the following air pressure and load conditions under the condition that the tire rotating speed is 60r/min, and then performs a low-speed uniformity test:

sedan tires: the test air pressure is 210kPa, and the test load is the maximum load capacity multiplied by 70 percent;

light truck or commercial vehicle tire: the test air pressure is 350kPa, and the test load is the maximum load capacity multiplied by 70%.

As a further improvement, the conditions of the high-speed uniformity test in the step 4) are as follows:

sedan tires: the test air pressure is 210kPa, the test load is the maximum load capacity multiplied by 70 percent, and the test speed is 120 km/h;

light truck or commercial vehicle tire: the test air pressure is 350kPa, the test load is the maximum load capacity multiplied by 70 percent, and the test speed is 120 km/h.

As a further improvement, the step 4) starts when the steady-state test condition is reached, and continues to perform data acquisition for 30 minutes, the data acquisition should be performed at intervals of 30 seconds, 8 circles of data are continuously acquired each time, and the 60 groups of data are taken as the initial high-speed uniformity data of the tire.

As a further improvement, said step 5) keeps loading the tire-rim assembly at the test load and the test temperature for the specified time as follows:

standard temperature test: the temperature 1 is 43.3 +/-3 ℃, and the time is 22 hours; the temperature 2 is 21 +/-3 ℃ for 2 hours;

and (3) normal temperature test: the temperature 1 is 21 +/-3 ℃ for 24 h.

As a further improvement, when the tire is mounted in the step 1), a lubricant is uniformly coated on the tire bead or the tire bead seat of the rim or both, and high-precision rims meeting the standard are selected and sequentially mounted on the test tire.

Further, the application also discloses a method for processing the automobile tire flat spot test data, which comprises the following steps:

1) carrying out average calculation on all the collected data to obtain representative 1-circle data, and taking high-speed uniformity before and after leveling as independent data sets;

2) decomposing the radial force and the longitudinal force of the tire by using a Fourier decomposition transformation formula so as to obtain the amplitude values and the phase angles of H1RFV and H2RFV, and H1TFV and H2 TFV;

3) using H1RFV and H2RFV of each stage after flat spot generation, H1TFV and H2TFV to respectively carry out vector difference calculation with H1RFV, H2RFV, H1TFV and H2TFV of each stage before flat spot generation to obtain time-based delta H1RFV, delta H2RFV, delta H1TFV and delta H2TFV, and using polar coordinates to map; fitting is performed by exponential function decay equation (1):

Mag(U_corr)＝A+B×e^-ct (1)

wherein A represents a permanent flat spot

A + B represents an initial flat point, t ═ 0;

c represents the time constant t in min.

Further, the present application also discloses an electronic device comprising a processor, a memory and a computer program stored on the memory and executable on the processor, wherein the computer program implements the method when executed by the processor.

Further, the present application also discloses a non-transitory computer-readable carrier medium storing program instructions, characterized in that the computer-readable storage medium stores thereon a computer program, which when executed by a processor implements the method.

By adopting the technical scheme, the method obtains high-speed uniformity data before and after the flat point, and then obtains the flat point data by carrying out data analysis and calculation, so that whether one tire meets the flat point requirement of the component can be evaluated, and the vibration problem of the vehicle can be diagnosed.

Drawings

Fig. 1 is a flow chart of a flat spot test of an automobile tire.

FIG. 2 is a 0 degree reference mark of the tire and rim combination.

Fig. 3 is a report of the flat spot test Δ H1RFV vs.

Fig. 4 is a tire flat spot test Δ H1TFV vs.

Detailed Description

The technical solution of the present invention is further described below by specific embodiments.

Two tires with specification 215/60R 1796H and the same pattern are selected as test tires, wherein one tire is a 1# tire, and the other tire is a 2# tire.

A high precision rim meeting the standards was mounted on a test tire # 1 and the tire was left to stand at ambient room temperature for at least 3 hours.

And after the parked tire and rim assembly is installed on a tire high-speed uniformity testing machine, carrying out unbalance measurement, and carrying out balance weight on the tire and rim assembly according to an unbalance measurement result until the static unbalance mass is reduced to be within 5 g.

The tire, rim and wheel assembly is marked with a 0 position as shown in fig. 2, the tire is warmed for 1min under the conditions of air pressure and load of table 1 under the condition of 60r/min of the tire rotating speed, then the low-speed uniformity test is carried out, the high point position of the H1RFV is obtained, the low point of the H1RFV is positioned by moving the high point position of the H1RFV by 180 degrees, and the low point position of the H1RFV is marked on the tire.

The high speed uniformity test was performed under the conditions shown in table 1, data acquisition was continued for 30 minutes, and data acquisition was performed at intervals of 30 seconds, with 8 rounds of data being continuously acquired each time, and the 60 sets of data were used as initial high speed uniformity data of the tire.

TABLE 1 high speed homogeneity test conditions

After the high-speed uniformity test is finished, the tire and rim assembly is placed on a flat point loading system which reaches the test temperature within 10min, the tire and rim assembly is loaded for a specified time under the test load and the standard test temperature (see table 2), and the flat point ballast positions are as follows: h1RFV low.

TABLE 2 Flat-point test temperature and ballast time

After flattening, the tire and rim assembly was mounted on a high speed uniformity machine within 10 minutes with the valve position at zero phase angle (fig. 1), and the high speed uniformity test was performed under the conditions of table 1, and these 60 sets of data were used as the high speed uniformity data after flattening. The test procedure of test tire # 1 was repeated for test tire # 2 to perform the flat spot test.

And (3) carrying out average value calculation on all 8 circles of data of the two tires obtained by the test to obtain representative 1 circle of data, and taking the high-speed uniformity before the flat point and the high-speed uniformity after the flat point as independent data sets. And (3) carrying out the decomposition of the radial force and the longitudinal force of the tire by using a Fourier decomposition transformation formula so as to obtain the amplitude magnitude and the phase angle of a radial force first harmonic (H1RFV) and a radial force second harmonic (H2RFV), and a longitudinal force first harmonic (H1TFV) and a longitudinal force second harmonic (H2 TFV).

Radial force first harmonic (H1RFV) and radial force second harmonic (H2RFV) of each stage after the flat spot is generated, the amplitude and the phase angle of longitudinal force first harmonic (H1TFV) and longitudinal force second harmonic (H2TFV) are respectively calculated with the amplitude and the phase angle of radial force first harmonic (H1RFV) and radial force second harmonic (H2RFV) of each stage before the flat spot, longitudinal force first harmonic (H1TFV) and longitudinal force second harmonic (H2TFV) to obtain time-based delta H1RFV, delta H2RFV, delta H1TFV and delta H2TFV, and the polar coordinates are used for drawing. Fitting calculation is carried out on the data of the two test tires through an exponential function decay formula (1). The test results are shown in fig. 3 and 4.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention, including any reference to the above-mentioned embodiments. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.