JP5836054B2 - Tire test method - Google Patents

Description

  The present invention relates to a tire test method and a tire test apparatus.

For example, when a vehicle such as an automobile passes over a pothole formed on the road surface, the tread portion of a tire mounted on the vehicle is connected to the road surface in the pothole, and the vehicle travels. If the front end portion located on the front side in the direction collides, the tire may be damaged such as deformation of the sidewall portion, pinch cut, or side cut.
Tire tests against such collisions are carried out by actual vehicle tests using vehicles, but there are problems such as time-consuming testing and damage to not only tires but also vehicles during collisions. Using a tire testing apparatus as shown in Patent Document 1 below, a tire in which the tread portion collides with the front end portion of the connection edge portion as described above is reproduced to easily test the tire. Test methods are being considered.

JP-A-6-273299

  However, in the conventional tire test method, no relationship with the actual vehicle test has been found, and it is difficult to accurately reproduce the tire in a collision state, and there is room for improvement in test accuracy. It was.

  This invention is made | formed in view of the situation mentioned above, The objective is to provide the tire test method which can test a tire with high precision and simply.

In order to solve the above problems, the present invention proposes the following means.
In the tire test method according to the present invention, in the actual vehicle test, the tread portion of the tire mounted on the vehicle passing over the pothole formed on the road surface is the connection edge portion connected to the road surface in the pothole. A tire in a collision state, which collides with a front end portion located on the front side in the traveling direction of the vehicle, is swung up around a tire support portion that supports the tire coaxially with a support shaft and a rotation shaft that extends in the support shaft direction. And a pendulum part that is supported so as to be able to be swung down and that collides with a tread part of a tire supported by the tire support part when the tip part is swung down from a state of being swung up around the rotation axis. A tire test method for reproducing and testing a tire using a tire test apparatus provided on the basis of a physical model obtained by modeling the actual vehicle test. Calculating an input energy the tread portion is input to the tire when impinging on the front end, on the basis of the input energy, and sets the potential energy of the pendulum part.

According to this invention, the input energy is calculated based on the physical model, and the potential energy of the pendulum part is set based on the input energy. Therefore, energy equivalent to the energy input in the actual vehicle test is input to the tire. Therefore, the tire in a collision state can be accurately reproduced and the tire can be tested with high accuracy.
Moreover, since it can implement using a tire testing apparatus, a tire can be tested simply.

  Further, as the physical model, a load applied downward to the suspension device of the vehicle, and a displacement amount by which a wheel shaft of a wheel with a tire is displaced by the suspension device being deformed by the load, , A load applied downward to the tire with the tire positioned on a flat surface, and a displacement in which the wheel shaft is displaced by the tire being deformed by the load. The relationship between the second physical model representing the relationship between the amount of tire and the amount of deformation of the tire, and the amount of deformation of the tire when the front end portion pushes the tread portion when the tread portion collides with the front end portion. A third physical model may be used.

  In this case, since the first physical model, the second physical model, and the third physical model are used as the physical model, the input energy can be calculated accurately and easily, and the tire can be calculated with higher accuracy. And it can be easily tested.

  Further, based on the physical model, the shape of the pothole, the approach speed of the vehicle when the tire enters the pothole, and the size of the tire, the tread portion is the front end in the actual vehicle test. The deformation amount and reaction force of the tire when it collides with the part may be calculated, and the input energy may be calculated based on these deformation amount and reaction force.

  In this case, since the input energy is calculated based on the deformation amount and reaction force of the tire, the input energy can be calculated more accurately and easily, and the tire can be tested more accurately and easily. can do.

  Further, a wheel in which the wheel shaft draws a deformation amount and a reaction force of the tire on a virtual plane along both the traveling direction and the vertical direction in the process in which the vehicle passes over the pothole in the actual vehicle test. You may calculate, calculating | requiring a locus | trajectory.

  In this case, since the deformation amount and reaction force of the tire are calculated while obtaining the wheel trajectory, the deformation amount and reaction force of the tire can be calculated accurately and simply, and the tire can be more reliably obtained. Highly accurate and simple testing.

Moreover, the tire test apparatus according to the reference example of the present invention is a tire test apparatus used in the tire test method, wherein at least one of the tire support part and the pendulum part is relative to a tip part of the pendulum part. The camber angle of the tire is movably arranged so as to change.

  According to the present invention, when the tire test method is performed, the pendulum is moved in a state where the camber angle of the tire with respect to the tip portion of the pendulum portion is changed by moving at least one of the tire support portion and the pendulum portion. Since the front end of the tire can collide with the tread portion of the tire, the tire test method can be implemented in various modes.

  According to the present invention, a tire can be tested with high accuracy and simplicity.

It is a figure explaining the actual vehicle test reproduced by the tire test method concerning one embodiment of the present invention. It is a figure explaining the actual vehicle test reproduced by the tire test method concerning one embodiment of the present invention. It is a graph showing the relationship between indentation force and the amount of deformation in the 3rd physical model. It is a graph showing the wheel locus | trajectory which the wheel axis drew on the virtual plane. It is a graph showing the relationship between the position of the running direction of a wheel axis, and the reaction force of a tire. It is a graph showing the relationship between the deformation amount and reaction force of a tire. It is a side view of the tire testing apparatus used for the tire testing method concerning one embodiment of the present invention. It is a top view of the tire testing apparatus shown in FIG. It is a partial top view which shows the state which changed the camber angle in the tire test apparatus shown in FIG.

Hereinafter, a tire test method according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1 and FIG. 2, in the tire test method, in the actual vehicle test, the tread portion T1 of the tire T mounted on the vehicle (not shown) that passes over the pothole 12 formed on the road surface 11 is the pothole 12. In the connection edge portion 13 connected to the road surface 11, the tire T in a collision state that collides with the front end portion 14 located on the front side in the traveling direction A of the vehicle is reproduced using a tire test device 20 described later. The tire T is tested.

First, the test conditions of the actual vehicle test will be described.
As shown in FIG. 1, the road surface 11 extends along the horizontal direction, and the traveling direction A is one of the horizontal directions.

The pothole 12 has a shape shown below.
That is, among the wall surfaces defining the pothole 12, the front wall surface 12a located on the front side in the traveling direction A and facing the rear side, and the rear wall surface 12b located on the rear side in the traveling direction A and facing the front side are vertical. Extends along the direction.
In addition, the front end portion 14 of the connecting edge 13 in the pothole 12 faces the rear obliquely upper side in the traveling direction A and has a radius of curvature Rc in the longitudinal sectional view along the traveling direction A and the vertical direction. And it is in the shape of a curved surface smoothly connected to the front wall surface 12a and the road surface 11. Further, the rear end portion 15 located on the rear side in the traveling direction A among the connecting edges 13 is formed by directly connecting the upper end edge of the rear wall surface 12b to the road surface 11, and in the longitudinal sectional view, the traveling direction. It has a right-angled shape facing the front diagonally upper side of A.
The depth of the pothole 12 is “Height”, and the length of the pothole 12 along the traveling direction A is “Length”.

The outer diameter of the tire T is Rt.
Further, when the tire T enters the pothole 12, that is, the tread portion T1 of the tire T comes into contact with the rear end portion 15 of the connection edge portion 13, and the traveling of the wheel shaft W1 of the wheel W with the tire T mounted thereon is performed. The approach speed of the vehicle when the position in the direction A is equal to the position in the traveling direction A of the rear end portion 15 is Vv.

  Here, in the tire test method, first, based on a physical model that models the actual vehicle test, when the tread portion T1 of the tire T collides with the front end portion 14 of the connection edge 13 in the actual vehicle test, the tire T The input energy input to is calculated. In the present embodiment, as the physical model, a first physical model related to a vehicle suspension device (not shown) and a second physical model and a third physical model related to the tire T are used.

  The first physical model represents a relationship between a load applied downward to the suspension device of the vehicle and a displacement amount by which the wheel shaft W1 is displaced by the suspension device being deformed by the load. The first physical model is expressed by the following equation (1), where the load is load and the displacement is displacement.

  The first term on the right side of equation (1) represents a spring component, the second term represents a damping component, and Dv in equation (1) is when a preset load Lv is applied. , Cv is the damping coefficient, and Mv is the unsprung mass. Dv and Cv can be calculated, for example, by a preliminary test or simulation. In the present embodiment, the load Lv is equivalent to the wheel load.

  The second physical model includes a load applied downward to the tire T with the tire T positioned on a flat surface, and a displacement in which the wheel shaft W1 is displaced by the tire T being deformed by the load. Expresses the relationship between quantity. The second physical model is expressed by the following equation (2), where load is load and displacement is displacement.

  Dp in the equation (2) represents the amount of displacement when a preset load Lp is applied, and can be calculated, for example, by a preliminary test or simulation. In the present embodiment, the load Lp is the same as the load of the wheel, like the load Lv.

  As shown in FIG. 2, the third physical model includes a pushing force in which the front end portion 14 pushes the tread portion T1 when the tread portion T1 of the tire T collides with the front end portion 14 of the connection edge 13, and the tire T Represents the relationship between the deformation amount of

Here, when the tread portion T1 of the tire T collides with the front end portion 14 of the connection edge portion 13, first, the sidewall portion bulges and deforms toward the outside in the tire width direction while compressing the air in the tire T. After that, the tire T is in a side pinch state, and the sidewall portion is sandwiched between the rim flange of the wheel W and the front end portion 14 of the connection edge portion 13 and is compressed and deformed. As shown in the graph of FIG. 3, the relationship between the pushing force and the deformation amount in FIG. 3 is an air spring as a model until the tire T is in a side pinch state (the range of deformation shown in FIG. 3 is DC ₁ or less). After the tire T is in the side pinch state (the range where the deflection shown in FIG. 3 is larger than _DC1 ), rubber compression is used as a model.
Such a third physical model is represented by the following expression (3), where the pushing force is “thrust” and the deformation amount is “deflection”.

  The first term on the right side of the equation (3) represents the air spring component, the second term and the third term represent the rubber compression component, and among these second and third terms, the second term is A non-linear spring component is represented, and the third term represents a damping component. The second term is, for example, based on the Hattori-Takei equation, the pushing force for pushing the tread portion T1 of the tire T in the side pinch state, and the compression amount of the sidewall portion that is compressed and deformed by the pushing force. The spring constant representing the relationship is obtained by integrating the compression amount.

Further, (3) D _C1 in formula is a variation amount when the pushing force T _C1 immediately before the tire T is a side pinched state is applied, D _C2 is infinity in the tire T the size of the a value obtained by subtracting the D _C1 from deformation amount when the pushing force is applied, T _C2 is a spring component in the side pinched state of the tire T, C _C2, the attenuation coefficient in the side pinched state of the tire T It is. Note that a broken line BL shown in FIG. 3 represents deflection = D _C1 + D _C2 , and is an asymptotic line of the expression (3).
Note that D _C1 , T _C1 , D _C2 , T _C2, and C _C2 can be calculated by, for example, preliminary tests or simulations. For example, D _C1 is the rim diameter of the wheel W, the height of the rim flange, and the tire. It can be calculated based on the rubber thickness of the sidewall portion of T, the outer diameter of the tire T, and the like.

  When obtaining the input energy using the physical model as described above, first, these physical models, the shape of the pothole 12, and the vehicle entry speed Vv when the tire T enters the pothole 12 are used. Based on the dimensions of the tire T, the deformation amount and reaction force of the tire T when the tread portion T1 of the tire T collides with the front end portion 14 of the connection edge portion 13 in the actual vehicle test is calculated.

  At this time, as shown in the graph of FIG. 4, the deformation amount and the reaction force of the tire T are determined in the course of the vehicle passing over the pothole 12 in the actual vehicle test. The calculation is performed while obtaining the wheel locus L drawn on the virtual plane I along both directions. In the graph shown in FIG. 4, the horizontal axis represents the position of the wheel axis W1 in the traveling direction A, and the vertical axis represents the position of the wheel axis W1 in the vertical direction. The origin of the axis is the position (hereinafter referred to as the initial position) O of the wheel axis W1 when the tire T enters the pot hole 12 on the virtual plane I.

  The wheel locus L is obtained by calculating the position of the wheel axis W1 on the virtual plane I every time a minute time elapses from when the wheel axis W1 is located at the initial position O. At this time, the position of the wheel axis W1 on the virtual plane I after the lapse of the minute time is based on the position and speed of the wheel axis W1 on the imaginary plane I before the lapse of the minute time. The calculation is performed by calculating the acceleration of the wheel axis W1 and the speed of the wheel axis W1 after a minute time has elapsed. Note that the speed of the wheel shaft W1 located at the initial position O is calculated based on the approach speed Vv of the vehicle.

  Here, the acceleration of the wheel axis W1 before the minute time elapses is calculated based on the physical model and the equation of motion. In the present embodiment, the acceleration of the wheel axis W1 is determined when the tire T is in a free fall, when the tire T is located on a flat surface, and when the tread portion T1 of the tire T is connected to the edge of the pothole 12. The calculation is performed separately for the case where the vehicle collides with the 13 front end portions 14.

  When the tire T is free-falling, the acceleration in the traveling direction A is 0, and the acceleration in the vertical direction is calculated based on the following equation (4) obtained from the equation (1).

  In the equation (4), z represents the amount of vertical displacement of the wheel shaft W1 from the initial position O. When the wheel shaft W1 is positioned below the initial position O, a negative value is obtained. When the wheel axis W1 is positioned above the initial position O, a positive value is taken.

  Further, when the tire T is positioned on a flat surface, for example, when the tread portion T1 of the tire T is in contact with the bottom surface of the pothole 12, the acceleration in the traveling direction A is 0, and the acceleration in the vertical direction is It is calculated based on the following formula (5) obtained from the formula (1) and the formula (2).

  As shown in FIG. 2, when the tread portion T1 of the tire T collides with the front end portion 14 of the connecting edge portion 13 of the pothole 12, the acceleration in the traveling direction A is based on the following equation (6). And the acceleration in the vertical direction is calculated based on the following equation (7).

  In the equation (6), x represents the amount of displacement of the wheel shaft W1 in the traveling direction A from the initial position O, and the wheel shaft W1 is located in front of the traveling direction A from the initial position O. Sometimes, a positive value is taken, and a negative value is taken when the wheel axis W1 is located behind the traveling direction A from the initial position O.

  Further, Xc in the equation (6) is in the traveling direction A between the initial position O and the center of curvature 16 in the longitudinal sectional view of the front end portion 13 of the pothole 12, as shown in FIG. Zc in the equation (7) is a size along the vertical direction between the initial position O and the center of curvature 16, and the following equations (8) and (9) respectively. ) Is calculated based on the equation.

  Further, the deflection in the equations (6) and (7) represents the deformation amount of the tire T when the tread portion T1 of the tire T collides with the front end portion 14 of the connection edge portion 13 in the actual vehicle test. Calculated based on equation (10).

Further, “thrust” in the equations (6) and (7) represents the reaction force of the tire T when the tread portion T1 of the tire T collides with the front end portion 14 of the connection edge portion 13 in the actual vehicle test. Then, the relationship between the thrust and the deflection, the (3) based on the equation, Defleciton is following (11) in the case of _{D C1} below, the following equation (12) when Defleciton is greater than _{D C1} Calculated based on

  From the above, while obtaining the wheel locus L, the tire T when the tread portion T1 of the tire T collides with the front end portion 14 of the connection edge portion 13 in the actual vehicle test based on the equations (10) to (12). The deformation that is the deformation and the reaction that is the thrust are calculated.

  Thereafter, as in the graphs shown in FIGS. 5 and 6, the input energy is calculated based on the relationship between the deformation amount of the tire T and the reaction force. 5 represents the relationship between the position of the wheel shaft W1 in the traveling direction A and the reaction force of the tire T, and the graph shown in FIG. 6 shows the deformation amount and reaction force of the tire T. Represents a relationship. In the graph shown in FIG. 6, the size of the region 18 sandwiched between the graph line 17 and the horizontal axis represents the magnitude of the input energy, whereby the input energy is calculated.

Next, based on the input energy, energy is input to the tire T using the tire test apparatus 20 shown in FIGS.
The tire test apparatus 20 is supported so as to be swingable up and down around a rotation axis O2 extending in the direction of the support shaft O1, and a tire support portion 21 that supports the tire T coaxially with the support shaft O1. And a pendulum portion 22 that collides with a tread portion T1 of the tire T supported by the tire support portion 21 when the tip end portion 22a is swung down from the state of being swung up around the axis O2.

The tire testing apparatus 20 is compliant with SAE J1981 Road hazard impact test for wheel and tire assemblies.
In the illustrated example, the support shaft O1 and the rotation shaft O2 are parallel to each other and extend along the horizontal direction, and both the shafts O1, O2 in a top view when viewed from the vertical direction. Are shifted from each other in a direction orthogonal to

The tire support portion 21 includes a base portion 24 fixed on an installation base 23 on which the tire testing apparatus 20 is installed, a side wall portion 25 erected on the base portion 24, and the support shaft on the side wall portion 25. And a mounting portion 26 that is disposed coaxially with O1 and on which the tire T is detachably mounted.
The pendulum part 22 includes a rod-like arm 27 having an arm axis O3 extending perpendicularly to the rotation axis O2, and a collision piece 28 provided at the tip of the arm 27.

The base end portion of the arm 27 is supported by a beam portion 30 installed between a plurality of support columns 29 erected on the installation table 23. The arm 27 may be adjustable in length along the direction of the arm axis O3.
The collision piece 28 constitutes the tip portion 22a of the pendulum portion 22 together with the tip portion of the arm 27, and is disposed on the swing-down side around the rotation axis O2 at the tip portion of the arm 27.

  The shape of the collision piece 28 can be set based on, for example, the shape of the front end portion 14 of the pot hole 12 in the actual vehicle test. In the present embodiment, the size of the collision piece 28 along the direction of the support axis O1 is the same regardless of the position around the rotation axis O2, and is larger than the tire width, for example. The tip edge 28a of the collision piece 28 extends linearly along the direction of the support axis O1.

  Here, at least one of the tire support portion 21 and the pendulum portion 22 is movably disposed so that the camber angle of the tire T with respect to the tip portion 22a of the pendulum portion 22 changes as shown in FIG. ing. In the present embodiment, the tire support portion 21 is disposed so as to be able to turn around a turning shaft (not shown) extending in the vertical direction, and when the tire support portion 21 turns around the turning shaft, the support shaft O1 is By turning around the turning axis in a horizontal plane, the camber angle of the tire T with respect to the collision piece 28 of the pendulum portion 22 is changed. In the illustrated example, the tire support 21 is detachably fixed to a guide member 31 disposed on the installation base 23 as shown in FIGS.

  When energy is input to the tire T using the tire test apparatus 20, the potential energy of the pendulum portion 22 is set based on the input energy. The potential energy of the pendulum part 22 can be adjusted based on, for example, the swing angle θ of the pendulum part 22, the weight of the pendulum part 22, the length of the arm 27 in the arm axis O3 direction, and the like. It is set so that when the 22 collision pieces 28 collide with the tread portion T1 of the tire T, energy equivalent to the input energy is input to the tire T.

  At this time, the collision piece 28 may collide with the tread portion T1 of the tire T in a state where the tire support portion 21 is turned and the camber angle of the tire T with respect to the collision piece 28 is changed. By changing the camber angle in this way, for example, the position of damage formed on the tire T in the collision state can be changed. The camber angle is preferably about 5 degrees, for example.

  And after inputting energy into the tire T using the tire test apparatus 20 as mentioned above, the presence or absence of the damage in the tire T is confirmed, and the test of the tire T is complete | finished.

As described above, according to the tire test method according to the present embodiment, the input energy is calculated based on the physical model, and the potential energy of the pendulum unit 22 is set based on the input energy. Energy equivalent to the input energy can be input to the tire T, and the tire T in the collision state can be accurately reproduced to test the tire T with high accuracy.
Moreover, since it can implement using the tire test apparatus 20, the tire T can be tested simply.

  In addition, since the first physical model, the second physical model, and the third physical model are used as the physical model, the input energy can be calculated accurately and easily, and the tire T can be calculated with higher accuracy. And it can be easily tested.

  Further, since the input energy is calculated based on the deformation amount and reaction force of the tire T, the input energy can be calculated more accurately and easily, and the tire T can be more accurately and easily calculated. Can be tested.

  Further, since the deformation amount and reaction force of the tire T are calculated while obtaining the wheel locus L, the deformation amount and reaction force of the tire T can be calculated accurately and simply, and the tire T It is possible to test with higher accuracy and convenience more reliably.

  Moreover, according to the tire test apparatus 20 according to the present embodiment, when the tire test method is performed, the tip end portion 22a of the pendulum portion 22 is moved by moving at least one of the tire support portion 21 and the pendulum portion 22. Since the tip end portion 22a of the pendulum portion 22 can collide with the tread portion T1 of the tire T in a state where the camber angle of the tire T is changed, the tire test method can be carried out in various modes.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the tire support portion 21 turns around the turning axis, so that the camber angle of the tire T with respect to the collision piece 28 of the pendulum portion 22 is changed. The camber angle may be changed by moving the part 22.

  Furthermore, in the above-described embodiment, the tire test apparatus 20 is arranged such that at least one of the tire support portion 21 and the pendulum portion 22 is movably arranged so that the camber angle of the tire T with respect to the tip portion 22a of the pendulum portion 22 changes. However, the tire test method may be performed using a tire test apparatus that is not movably disposed and does not change the camber angle.

  In addition, it is possible to appropriately replace the constituent elements in the embodiment with known constituent elements without departing from the spirit of the present invention, and the above-described modified examples may be appropriately combined.

DESCRIPTION OF SYMBOLS 11 Road surface 12 Pothole 13 Connection edge part 14 Front end part 20 Tire test device 21 Tire support part 22 Pendulum part 22a Tip part O1 Support axis O2 Rotation axis I Virtual plane L Wheel locus T Tire T1 Tread part W Wheel W1 Wheel axis

Claims (4)

In an actual vehicle test, a tread portion of a tire attached to a vehicle passing over a pothole formed on a road surface is positioned on a front side in a traveling direction of the vehicle among connection edge portions connected to the road surface in the pothole. The tire in the collision state formed by colliding with the front end
A tire support for supporting the tire coaxially with the support shaft;
It is supported so that it can be swung up and down around the rotation axis extending in the direction of the support shaft, and the tip is supported by the tire support when swung down from the state of being swung up around the rotation axis. A pendulum that collides with the tread of the tire,
A tire test method for reproducing and testing a tire using a tire test apparatus comprising:
Based on a physical model obtained by modeling the actual vehicle test, the input energy input to the tire when the tread portion collides with the front end portion in the actual vehicle test is calculated, and the pendulum unit is calculated based on the input energy. A tire test method characterized by setting the potential energy of the tire. The tire test method according to claim 1,
As the physical model,
A first representing a relationship between a load applied downward to the suspension device of the vehicle and a displacement amount of a wheel shaft of a wheel on which a tire is mounted is displaced by the suspension device being deformed by the load. Physical model of
A second physical model representing a relationship between a load applied downward to the tire in a state where the tire is positioned on a flat surface and a displacement amount by which the wheel shaft is displaced by the tire being deformed by the load. When,
A third physical model representing a relationship between a pushing force with which the front end portion pushes the tread portion when the tread portion collides with the front end portion and a deformation amount of a tire is used. Tire test method. The tire test method according to claim 2,
Based on the physical model, the shape of the pothole, the approach speed of the vehicle when the tire enters the pothole, and the dimensions of the tire, the tread portion is located at the front end portion in the actual vehicle test. A tire test method, comprising: calculating a deformation amount and a reaction force of a tire at the time of collision, and calculating the input energy based on the deformation amount and the reaction force. The tire test method according to claim 3,
A wheel locus drawn by the wheel shaft on a virtual plane along both the traveling direction and the vertical direction in the process in which the vehicle passes over the pothole in the actual vehicle test. A tire test method characterized by calculating while obtaining.

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