KR102294792B1 - A testing apparatus for a tire - Google Patents

Abstract

The present invention relates to a method of testing lateral hydroplaning of a tire and, more specifically, to a method of testing lateral hydroplaning of a tire using a driving speed variation, a rotation radius change rate and a travel distance of a vehicle being driven. The method of testing lateral hydroplaning of a tire, which occurs when a vehicle is driven on a wet road surface of a predetermined section while maintaining a predetermined steering angle, includes the following steps of: calculating a lateral hydroplaning parameter by multiplying a driving speed variation, a rotation radius change rate and a travel distance of the vehicle being driven; and determining lateral hydroplaning of the tire by comparing the calculated lateral hydroplaning parameter to a reference value. Therefore, there can be an advantage of enabling a more intuitive test by testing and evaluating the lateral hydroplaning with a lateral acceleration value.

Description

Tire diaphragm phenomenon test method {A testing apparatus for a tire}

The present invention relates to a method for testing tire diaphragm phenomenon, and more particularly, to a method for testing tire diaphragm phenomenon using a change in the running speed of a traveling vehicle, a rate of change in a turning radius, and a mileage.

The drainage performance of tires is a very important part when driving in the rain.

In particular, aquaplaning is a part that must be considered when designing a tire because it can lead to a very fatal accident while driving a vehicle.

The aquaplaning phenomenon refers to a phenomenon in which the tire slips due to the tire's poor drainage performance.

That is, the water film phenomenon is expressed from the limit of the drainage performance of the tire.

In other words, the vehicle's tires lose grip by the water film on wet road surfaces, which can lead to a very dangerous situation.

It is designed to evaluate the drainage properties of tires against such aquaplaning, and is an essential inspection item in tire development.

Conventionally, in the tire aquaplaning experiment, the transverse aquaplaning was evaluated as a lateral acceleration for each speed as shown in FIGS. 1 and 2 .

The conventional hydrofilm phenomenon experiment was as follows.

That is, as shown in FIG. 1 , the lateral acceleration is measured when the vehicle is driven at a constant speed (eg, 50 km/h) to draw a curve having a predetermined radius through the water curtain section.

At this time, the depth of the water film in the meningeal section is 6 to 10 millimeters, and the length of the meningum section is between about 20 to 25 meters.

When this is arranged on the coordinates, the plane on which the test vehicle travels is set as a plane composed of the X and Y axes as shown in FIG. 2, and the intersection of the X and Y axes is the center of the turning radius.

The vehicle is driven to draw a constant curve while moving from the X-axis to the Y-axis, and the experiment is conducted in a state where there is no change in the steering angle while driving.

When one lateral acceleration measurement is finished, repeat it again, but experiment by changing only the vehicle speed.

In other words, this time, the lateral acceleration applied while driving is measured by changing the speed of the vehicle to 55 km/h under the same conditions.

Next, the experiment is performed again under the same conditions, but the lateral acceleration is measured by performing the experiment at a speed added 5 km/h to the speed of the vehicle in the previous experiment.

The lateral acceleration values for each vehicle traveling speed measured in this way are expressed in a graph as shown in FIG. 3 .

However, since the graph is not intuitive in discriminating the conventional diaphragm phenomenon, there is a problem in that it is difficult to understand the graph and the results of the diaphragm phenomenon other than experts.

US 207964 B1

The present invention to overcome the above problems of the prior art can be intuitively grasped by providing a test method that integrates the most important properties for the diaphragm phenomenon, such as speed change, rotation angle change, and rotation radius change, in a specific and three-dimensional way. Its purpose is to make

In the method for testing the diaphragm phenomenon of a tire that occurs when a driving vehicle drives on a wet road surface of a certain section while maintaining a predetermined steering angle, the driving speed change of the driving vehicle, the change rate of the turning radius of the driving vehicle, and the driving calculating a diaphragm parameter by multiplying all the mileage of the vehicle; determining the diaphragm phenomenon of the tire by comparing the calculated diaphragm parameter with a reference value; It includes a tire diaphragm test method comprising a.

In addition, the reference value includes a tire diaphragm phenomenon test method, characterized in that the driving distance of the driving vehicle is 25 m, the turning radius of the driving vehicle is 100 m, and the driving speed of the driving vehicle is 50 km/h.

In addition, the rate of change of the turning radius includes a tire diaphragm phenomenon test method, characterized in that the value obtained by dividing the actual turning radius of the driving vehicle by 100 m.

In addition, the thickness of the water film on the wet road surface is 6 mm or more and 10 mm or less.

In addition, the driving speed change of the driving vehicle, the change rate of the turning radius of the driving vehicle, and the mileage of the driving vehicle are obtained from a V-BOX instrument and GPS mounted on the driving vehicle. include

According to the present invention as described above, there are the following effects.

First, it has the advantage of enabling a more intuitive experiment by test-evaluating the diaphragm phenomenon with the value of lateral acceleration.

Second, effective experiments are possible because the size of the diaphragm phenomenon can be estimated through the change in volume.

1 and 2 are a conventional diaphragm phenomenon test method
3 is a conventional diaphragm test graph
4 (a), 4 (b) are measuring instruments according to a preferred embodiment of the present invention
5 and 6 are conceptual diagrams of deriving a diaphragm phenomenon parameter according to a preferred embodiment of the present invention.
7 is a table of experimental results according to a preferred embodiment of the present invention;

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and will be described in detail in the detailed description. However, this is not intended to limit the present invention to a specific embodiment, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

In describing each figure, like reference numerals are used for like elements.

The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. The term “and/or” includes a combination of a plurality of related listed items or any of a plurality of related listed items.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. shouldn't

First, the terms used in the description are summarized.

The speed change amount (dv _n ) represents the speed without diaphragm phenomenon (v ₀ ) and the speed change amount value in the nth experiment.

The change in the turning radius (dr _n ) represents the value of the change in the turning radius in the nth experiment from the turning radius without diaphragm (R _{0 ).}

The rotation angle change amount (dθ _n ) represents the rotation angle change amount value in the nth experiment from the rotation angle without diaphragm phenomenon (θ _{0 ).}

On the other hand, dV _n represents the volume change value in the nth experiment.

Here, “n” represents the experimental order.

However, n=0 may indicate an experimental condition without diaphragm phenomenon.

In other words, when n = 0, it is the initial condition that the diaphragm phenomenon does not occur.

Meanwhile, the reference value in a preferred embodiment of the present invention means that the driving distance of the driving vehicle is 25 m, the turning radius of the driving vehicle is 100 m, the driving speed of the driving vehicle is 50 km/h, and the thickness of the water film on the wet road surface is 6 mm or more less than 10mm.

In addition, the rate of change of the turning radius is a value obtained by dividing the actual turning radius of the driving vehicle by 100 m.

The present invention uses the principle that the larger the diaphragm phenomenon of the vehicle, the larger the turning radius of the vehicle and the smaller the amount of change in the turning angle of the vehicle.

Also, under the same conditions, it is clear that the diaphragm phenomenon on the same wet road surface is more likely to occur as the vehicle speed increases.

The diaphragm phenomenon test and evaluation method in the present invention is intended to be expressed as a volume change by using the speed change amount, the turning radius change amount, and the turning angle change amount of a vehicle traveling on a wet road surface.

In other words, a method for testing the diaphragm phenomenon of a tire that occurs when a driving vehicle runs on a wet road surface of a certain section while maintaining a predetermined steering angle will be described.

That is, the diaphragm phenomenon test method according to a preferred embodiment of the present invention includes the steps of calculating the diaphragm phenomenon parameters by multiplying all of the driving speed change of the driving vehicle, the rate of change of the turning radius of the driving vehicle, and the driving distance of the driving vehicle; and comparing the diaphragm parameter with a reference value to determine the diaphragm phenomenon of the tire.

Meanwhile, as shown in FIG. 4 , a V-BOX measuring instrument and a GPS, which are equipment for measuring a vehicle's position and movement and speed, may be used in the test evaluation of the present invention.

That is, it is possible to measure the driving speed, driving distance, acceleration, lap time, and current vehicle location information of the vehicle based on the next-generation high-performance satellite reception technology using the V-BOX instrument and GPS.

In other words, it may be preferable to obtain the change in the driving speed of the driving vehicle, the rate of change of the turning radius of the driving vehicle, and the mileage of the driving vehicle from the V-BOX measuring instrument and GPS mounted on the driving vehicle.

The coordinate axis in FIG. 5 includes the X-axis and the Y-axis constituting the driving surface on which the vehicle travels, and includes the X-axis and the Y-axis and the speed axis V, respectively, perpendicular to each other.

The vehicle is set to travel on a plane composed of the X and Y axes, and the intersection of the X and Y axes is the center of the turning radius.

The vehicle is driven to draw a constant curve while moving from the X-axis to the Y-axis, but the experiment is conducted in a state where there is no change in the steering angle while driving.

In other words, the steering angle of the vehicle during the experiment is constant.

More specifically, in the initial condition, that is, under the condition of _n =0, dv n = 0, r ₀ = 100m, and dθ _n = 0.250 rad.

That is, when n = 0, the test vehicle is cruising along a driving path with a turning radius of 100 m, and passes on a wet road surface only while turning by 0.250 rad.

Whenever the experimental order is increased, the behavior of the vehicle is measured while only the vehicle speed is increased by a preset value while other variables are fixed.

That is, it is assumed that the diaphragm phenomenon increases as the experimental order increases to an integer as in n = 1, 2, 3.

In other words, it is considered that diaphragm occurs from n = 1.

In addition, it should be noted that as the number of trials increases, the driving speed of the vehicle is constantly increased by a preset value.

As an example, the vehicle traveling speed according to the increase in the experimental order may be set to increase by 5 km/h whenever the order is increased by 1.

That is, the preset value may be 5 km/h.

Transverse film phenomenon is the greater the volume change amount (dv _n) proportional to the calculated volume change amount (dv _n) transverse film phenomenon is increased.

In this case, the calculated volume change (dv _n ) is the transverse water phenomenon parameter.

Here, it is possible to measure the _{amount of angular change (dθ n} ) and the amount of time change (dt _n ) in the nth experiment through a V-BOX instrument (hereinafter referred to as a measuring instrument).

The turning radius can be obtained from the following equation.

Rotation radius (r _n ) = Collecting _{speed (v n} ) X (Angular change amount (dθ _n )/Time change amount (dt _n ))

That is, the turning radius (r _n ) can be obtained from the velocity (v _n ) measured by the instrument, the time change (dt _n ), and the angular change amount (dθ) according to the position change.

On the other hand, _{assuming that the initial radius (r 0} ) of the test site is 100 m, the amount of change in the turning radius (dr _n ) is the value obtained by subtracting 100 m from the turning radius (r _{n ) in the nth experiment.}

That is, it is possible to derive the speed change (dv _n ) between the experimental speed (v _{n ) from the initial speed (v 0} ) without the diaphragm phenomenon, and to obtain both the turning radius change amount (dr _n ) and the rotation angle change amount (dθ _n ). and the volume change (dV _n ) can be calculated from them.

In FIG. 6 , the first volume change amount dV ₁ when n=1 is obtained as follows.

In other words, the volume change (dV _n ) can be obtained as follows.

dV ₁ = dv ₁ × r ₁ dθ ₁ ×dr ₁

On the other hand, the n-th volume change amount (dV _n ) at the n-th order is obtained as follows.

dV _n = dv _n × r _n dθ _n ×dr _n

As the volume change (dV) increases, the diaphragm phenomenon increases.

On the other hand, it should be noted that the value of _{r n} dθ _{n is constant at 25 meters.}

That is, the r _n dθ _n value means the distance value of 25 meters in which the experimental vehicle traveled through the water curtain section.

Regardless of the experimental order, only the volume change (dV) of the vehicle during the 25-meter water film section is considered.

In other words, the volume change amount (dV) is a value that can change according to the experimental order, but the value of r _n dθ _n does not change and is fixed.

More specifically, n=1,2,3… As shown in Fig. 7, the volume change table for the two types of tires A and B as the experimental order increases.

In the first experiment, tire A had a volume change (dVn) of 0.2, whereas that of tire B was 0.1.

Considering only this, it can be judged that the B-tire has better diaphragm than the A-tire.

However, as the number of experiments increases, the volume change (dVn) of the B tire exceeds the volume change (dVn) of the A tire from the 5th round.

That is, in the 5th experiment, the volume change of tire A was 42.7 while the volume change of tire B was 84.9.

Such a difference becomes larger as the order increases with the 6th and 7th experiments.

In the 7th experiment, the volume change of tire A was 320.4, while the volume change of tire B was 1255.8, showing a difference of about four times.

Therefore, as shown in FIG. 7 , from the results of the 7 tests in total, it can be determined that the A-tire is less prone to diaphragm than the B-tire, and thus is more favorable to the diaphragm.

In other words, it can be determined that the B tire has a larger volume change (dVn) than the A tire, and thus is vulnerable to the diaphragm phenomenon.

In other words, the table of FIG. 7 shows the results of comparing the diaphragm phenomenon when _{both the B tire and the A tire drive the same distance in the 25 m section, that is, the r n} dθ _{n value is 25 m.}

dv _{n :} diaphragmatic phenomenon parameter
_{dr n :} Change of turning radius
dv _{n :} speed change
dθ _{n :} Rotation angular change amount

Claims (5)

In the method for testing the diaphragm phenomenon of a tire that occurs when a driving vehicle drives on a wet road surface of a certain section while maintaining a predetermined steering angle,
calculating a diaphragm phenomenon parameter by multiplying the change in the running speed of the running vehicle, the rate of change in the turning radius of the running vehicle, and the running distance of the running vehicle;
determining the diaphragm phenomenon of the tire by comparing the calculated diaphragm parameter with a reference value; containing,
Tire diaphragm test method.
According to claim 1,
The reference value is characterized in that the traveling distance of the traveling vehicle is 25 m, the turning radius of the traveling vehicle is 100 m, and the traveling speed of the traveling vehicle is 50 km/h,
Tire diaphragm test method.
According to claim 1,
The turning radius change rate is characterized in that the value obtained by dividing the actual turning radius of the driving vehicle by 100m,
Tire diaphragm test method.
According to claim 1,
The thickness of the water film of the wet road surface is 6 mm or more and 10 mm or less,
Tire diaphragm test method.
According to claim 1,
The driving speed change of the driving vehicle, the rate of change of the turning radius of the driving vehicle, and the driving distance of the driving vehicle are obtained from a V-BOX measuring instrument and GPS mounted on the driving vehicle,
Tire diaphragm test method.

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